Screening of hyperthermostable proteins from hyperthermophilic archaeon Palaeococcus pacificus DY20341T - Junxi Hu; Jing Zhang; Jiaju Xu; Xiang Zeng (Extremophiles, 2026)

Salinity and ionic composition drive prokaryotic community assembly in Tuolekule Lake, China - Liping Xu; Longteng Fang; Rehan Shayibas; Yiman Li; Reziyamu Wufuer; Shiyang Lu; Nan Wei; Dong Wang; Zhiwei Zhang (Extremophiles, 2026)

Correction: Cultivation and characterization of haloarchaea from Moroccan Atlantic solar salterns: insights into diversity and bioactive potential - Imane Charroud; Naima Boum’handi; Mohamed Alouani; Altaf El Blidi; Yannick Fleury; Mohamed Jebbar (Extremophiles, 2026)

L-asparaginase by filamentous fungi and yeasts from lichens and soils across maritime Antarctic islands - Averlane Vieira da Silva; Bárbara Emanuelle Fernandes Ferro; Vanessa Daiany Vieira Medeiros; Valdilene Canazart dos Santos; Maria Nicolle Pereira da Silva; Cledna Kaline dos Santos Duarte; Aline Cavalcanti de Queiroz; Magna Suzana Alexandre Moreira; Luiz Henrique Rosa; Alysson Wagner Fernandes Duarte (Extremophiles, 2026)

Rising from the fragments: a multi-factorial regulatory framework of DNA damage response in Deinococcus radiodurans - Narasimha Anaganti; Aman Kumar Ujaoney; Mahesh Kumar Padwal; Bhakti Basu (Extremophiles, 2026)

Elucidation of D-amino acid metabolic activity of ornithine decarboxylase from the hyperthermophile Thermotoga maritima - Kanon Nogawa; Tetsuya Miyamoto (Extremophiles, 2026)

Long-term heavy metal contamination altered the structure and function of microbial communities in agricultural soil - Hongling Liu; Yonghua Zhang; Keke Yang; Huan Li; Susu Cao; Yuanyuan Bao; Lu Feng; Li Zhang; Jingping Niu; Tian Tian (Extremophiles, 2026)

Decoding the cold: integrated secretome profiling reveals extracellular adaptation mechanisms in Glaciozyma antarctica - Shuhaila Mat-Sharani; Farahayu Khairuddin; Nik Yusnoraini Yusof; Norfarhan Mohd-Assaad; Abdul Munir Abdul Murad; Farah Diba Abu Bakar; Nor Muhammad Mahadi; Nurdiana Nordin; Shazilah Kamaruddin (Extremophiles, 2026)

Large-scale comparative genomics of chitin metabolism in extremely halophilic archaea from the Halobacteria class - A. S. Tulenkov; A. G. Elcheninov; D. Y. Sorokin (Extremophiles, 2026)

Consortium of Sulfobacillus thermosulfidooxidans and Alicyclobacillus ferrooxydans facilitate pyrite bioleaching - Chang Liu; Xiu-Tong Li; Yuqian Han; Wenxing Li; Yongqiang Gao; Chengying Jiang; Ying Liu; Yanning Zheng (Extremophiles, 2026)

Comparative metagenomic analysis of microbial communities: unravelling microbial communities from the great Rann of Kachchh and coastal saltpans, Gujarat, India - Rehnuma Ghori; Dineshram Ramadoss; Paul A. Ramsland; Ewan W. Blanch; Bharath Subramanyam Ammanabrolu (Extremophiles, 2026)

Proteome-wide mapping of cysteine persulfidation in deep-sea hyperthermophilic archaea - Ling Fu; Xuegong Li; Shaowei Liu; Yunhan Zhang; Jing Yang (Extremophiles, 2026)

Genomic and functional profiles of two Antarctic chitin-degrading Arthrobacter strains - Yesenia M. Santa-Cruz Vasquez; Luis Gabriel Cueva-Yesquen; Luiz Henrique Rosa; Alysson Wagner Fernandes Duarte; Valéria Maia de Oliveira (Extremophiles, 2026)
Chitin is the second most abundant polysaccharide in nature and constitutes a key structural component in the cell wall of fungi and invertebrate exoskeletons. Chitinases produced by Antarctic organisms have demonstrated high catalytic efficiency, being promising tools for sustainable biotechnological processes. Therefore, the objective of this study was to identify the genes responsible for chitin degradation in the genomes of two Antarctic Arthrobacter strains, as well as to evaluate their biotechnological potential. Whole-genome sequencing followed by phylogenomic analysis revealed that both strains 492 and 285 belong to the species Arthrobacter psychrochitiniphilus. Genome assembly and annotation confirmed the genetic potential for chitinase production, showing that both bacteria possess the gene encoding type C chitinase (Chi C) from the GH18 family. Genomic comparative analysis revealed that they possess a total of eleven genes related to glycoside hydrolases (GH) and carbohydrate-binding modules (CBM), highlighting GH13 and GH65. Arthrobacter psychrochitiniphilus 492 was classified as psychrophilic, while A. psychrochitiniphilus 285 was classified as mesophilic-psychrotolerant. The enzyme production by A. psychrochitiniphilus 285 was 19.9 U/L, in 96 h at 15 °C, and the chitinase showed activity against the Aspergillus sp. series nigri CBMAI 1846, indicating promising potential for the formulation of bioinoculants and sustainable agriculture.

Cultivation and characterization of haloarchaea from Moroccan Atlantic solar salterns: insights into diversity and bioactive potential - Imane Charroud; Naima Boum’handi; Mohamed Alouani; Altaf El Blidi; Yannick Fleury; Mohamed Jebbar (Extremophiles, 2026)

Fe-driven ROS mitigation in Leptolyngbya JSC-1: optimizing growth using response surface method - Sikandar Khan; Maryam Akhoundian; Pengcheng Fu (Extremophiles, 2026)

Extreme Arabian environments and their microbiomes: new frontiers for astrobiology and biosignature discovery - Júnia Schultz; Paula M. García-Martínez; Sharifah Altalhi; Nicholas Kontis; Alef dos Santos; Alexandre Soares Rosado (Extremophiles, 2026)

Optimization of cellulase production using Bacillus thuringiensis strain TS-04-A halophilic bacterium - Vaishnavi Balaji; Aparna Ganapathy Vilasam Sreekala; Vinod Kumar Nathan (Extremophiles, 2026)

Common capacity for far-red light photosynthesis in a canyon thermophilic freshwater system - Ivan J. Moreno; Alexander Bogdanov; Brian Palenik (Extremophiles, 2026)
Photosynthetic life is based on absorbing sunlight and turning it into biologically usable energy. In many cases however, canopy-like structures and cavern-like habitats in terrestrial environments can limit the intensity and alter the spectra of light. One acclimation to use filtered light in the near infrared range, typically between 700 and 800 nm is named far-red light photoacclimation or FaRLiP as in recent studies of cyanobacteria. Here we report the common capacity for FaRLiP in the dominant cyanobacterial genera in a canyon hot spring microbial mat ecosystem. We identified FaRLiP in the genomes of cyanobacterial isolates and the metagenomes of mat samples. We show using absorption spectroscopy and HPLC that under far red-light specific isolates show an increase in far red-light absorption and the presence of Chl f . Springs in narrow canyons are a microniche where FaRLiP seems highly ecologically advantageous.

Integration of ploidy, Orc1/Cdc6 homolog function, and lysine acetylation with phosphate limitation and UV stress responses of Haloferax volcanii - Daniel Gal; Colton Smith; Kelsey Cooper; Ricardo L. Couto-Rodríguez; Julie A. Maupin-Furlow (Extremophiles, 2026)

Isolation and characterization of anaerobic thermophilic bacterium Caldisericum insulae sp.nov., the second cultivated representative of the phylum Caldisericota - Nataliya M. Ratnikova; A. Y. Merkel; A. A. Novikov; A. I. Slobodkin (Extremophiles, 2026)

Halovenus anhuiensis sp. nov. and Natronomonas salinimetallica sp. nov., two extremely halophilic archaeon isolated from a salt mine - Ya-Ling Mao; Aodi Zhang; Tao Hong; Yue Ding; Jingfang Liu; Jing Hou; Heng-Lin Cui; Shaoxing Chen (Extremophiles, 2026)

Genomic insights into abiotic stress tolerance in polar lichen-associated Sphingomonas sp. PAMC26617 and Sphingomonas sp. PAMC26621 - Anamika Khanal; So-Ra Han; Jun Hyuck Lee; Tae-Jin Oh (Extremophiles, 2026)

Exploring Marinilactibacillus sp from Lake Urmia as a novel halophilic source of antibacterial bioactive compounds - Shabnam Golbouy Daghdari; Azam Jafari; Hussein Eisazadeh; Amir Tukmechi (Extremophiles, 2026)

In situ filtration reveals salinity-driven dynamics of prokaryotic and eukaryotic communities in the Yinggehai solar saltern - Zijia Wang; Jian Zhang; Shijie Bai (Extremophiles, 2026)

Diversity and composition of fungal communities in freshwater environments of the Fildes Region, Antarctica - Chao Dong; Jing Su; Li-Yan Yu; Tao Zhang (Extremophiles, 2026)

Ecological distribution and environmental preference of the deep-branching archaeal lineage in high-temperature hot springs of Central Kyushu, Japan - Kai Yoshitake; Keigo Mori; Jun-ichiro Ishibashi; Katsunori Yanagawa (Extremophiles, 2026)

Structural and functional annotation of Glaciozyma antarctica hypothetical proteins using integrated modeling pipelines - Fatin Izzati Abdul Hadi; Doris Huai Xia Quay; Nor Muhammad Mahadi; Mohd Firdaus-Raih; Su Datt Lam (Extremophiles, 2026)

Elucidating the mechanisms of anthracene and phenanthrene degradation by the halophile Vreelandella piezotolerant DM1 - Ramanathan Duraimurugan; Selvakumar Santhosh; Shahul Hameed Mohamed Hanifa; T. Nageswara Rao; Jayaraman Narenkumar; Zhen Fang; Sandhanasamy Devanesan; Mohammad Ahmad Wadaan; Aruliah Rajasekar; Rajaram Rajamohan (Extremophiles, 2026)

Antitumor potential of glutaminase- and urease-free L-asparaginase from Antarctic fungus Mortierella turficola - Grécia Antonella Nina Flores; Marahia Isabel Guevara Robayo; Luiz Henrique Rosa; Jorge Luis Maria Ruiz; Michel Rodrigo Zambrano Passarini (Extremophiles, 2025)

O-Acetyl-l-homoserine sulfhydrylase from Thermotoga maritima has five enzyme activities - Tetsuya Miyamoto; Kumiko Sakai-Kato (Extremophiles, 2025)

hEDTA and EDDS as sustainable and harmless alternatives to NTA as trace metal chelators in Methanothermobacter marburgensis cultivation - Fabian Schwarzmann; Elisa Hilts; Shubham Gurav; Franziska Steger; Simon K.-M. R. Rittmann; Christian Fink (Extremophiles, 2025)
The thermophilic methanogenic archaea Methanothermobacter spp. are applied as archaeal cell factories in industrial processes for methane production. Recently, secretion of commodity chemicals by M. marburgensis , such as amino acids, organic acids, or lipids has been observed. Together with the genetic tools available, genetically engineered cell factories for commodity chemical production from CO 2 can be developed. However, the toxicity of the commonly used trace metal chelator Nitrilotriacetic acid (NTA) for M. marburgensis blocks potential regulatory approval for human applications. Therefore, we identified EDDS and hEDTA as suitable non-toxic alternatives as metal chelators for M. marburgensis . While EDDS reduces the specific growth rate (µ) of M. marburgensis by 40%, hEDTA shows the same µ as with NTA usage. Additionally, hEDTA offers cost wise a sustainable economic alternative to NTA with 23 € m − 3 of growth medium compared to 13 € m − 3 with NTA. With hEDTA as a harmless alternative to NTA, we are one step closer to industrial sustainable commodity chemical production from CO 2 with M. marburgensis .

A culture-independent study of the structure, functions and methane oxidation activity of microbial communities of geothermal springs in Dagestan - A. I. Slobodkin; I. I. Rusanov; G. B. Slobodkina; N. A. Chernyh; A. R. Stroeva; A. Y. Merkel (Extremophiles, 2025)

Enzymatic potential of dairy microbes from high-altitude niches: emerging resource with industrial applications - Deepika Nag; Sneha; Tamanna; Dharam Singh (Extremophiles, 2025)

Elucidating the role of compatible solutes in growth protection and amelioration of oxidative stress in the thermophilic cyanobacterium Mastigocladus sp. TA-8 during temperature shifts - Sanjay Sharma; Sindhunath Chakraborty; Vandana Sindhu; Arun Kumar Mishra; Satya Shila Singh (Extremophiles, 2025)

Co-expression of environmental extremophilic genes strongly enhances Escherichia coli cross-protection to abiotic stress - Melany Yalibeth Loera; Carolina González de Figueras; Mercedes Sánchez-Costa; Pablo Martínez-Rodríguez; Salvador Mirete; María Lamprecht-Grandío; Silvia Díaz; José Eduardo González-Pastor; Jorge Díaz-Rullo (Extremophiles, 2025)

Metal–induced biofilm formation by radiation resistant bacteria Deinococcus radiodurans and Deinococcus indicus - André G. Gouveia; Amin Taoufiq; Wilson Antunes; Célia V. Romão (Extremophiles, 2025)

Metal tolerance and recovery mechanisms of Priestia sp. Mn7 under pH 1.5 - Chikara Takano; Kazunori Nakashima; Hideki Aoyagi; Takaaki Kojima; Satoru Kawasaki (Extremophiles, 2025)

Diversity of culturable fungi in Antarctic lakes and their potential for producing compounds of biotechnological interest - Láuren Machado Drumond de Souza; Júlia de Paula Muzetti Ribeiro; Debora Luiza Costa Barreto; Elisa Amorim Amâncio Teixeira; Camila Rodrigues de Carvalho; Juan Manuel Lirio; Silvia H. Coria; Peter Convey; Fábio Soares de Oliveira; Charles L. Cantrell; Stephen Oscar Duke; Carlos Augusto Rosa; et al. (Extremophiles, 2025)

Isolation, screening, and molecular identification of culturable halophilic bacteria with enzymatic and antimicrobial potential from the saline soils of Arzew salt lake, Algeria - Amina Meglali; Lotfi Ghellai; Taha Ahmed Benabbou (Extremophiles, 2025)

Halobacillus as source of natural products and enzyme factories - Andri Frediansyah; Dhea Sandra Fitriany (Extremophiles, 2025)

Actinomycetes from high altitude salt lake Tso-Kar of Ladakh offers bright prospects for antimycobacterial drug discovery especially for drug resistant mycobacteria - Ishfaq Ahmad Baba; Zubair Ahmad Wani; Mohamad Mosa Mubarak; Zahoor Ahmad (Extremophiles, 2025)

Structural insight into the unique substrate specificity of glutamate dehydrogenase from Saccharolobus solfataricus - Itsuki Okabe; Masashi Hirano; Taketo Ohmori; Minako Segawa; Kazunari Yoneda; Toshihisa Ohshima; Haruhiko Sakuraba (Extremophiles, 2025)

Idiomarina aminovorans sp. nov., a halophilic bacterium isolated from the Llamara salt pan in the Atacama Desert of northern Chile - Christian Hintersatz; Luis Antonio Rojas; Sean Ting-Shyang Wei; Sabine Kutschke; Angela Thewes; Falk Lehmann; Rohan Jain; Katrin Pollmann (Extremophiles, 2025)
The Atacama Desert, one of the most extreme environments on our planet, harbors a plethora of unique microbial communities adapted to the harsh conditions of the habitat. In this study, strain ATCH4 T , a novel Gram-stain-negative, curved rod-shaped bacterium, was isolated from the Llamara salt pan, located in the Atacama Desert in the north of Chile. ATCH4 T was capable of growth within a range of 3–12% (w/v) NaCl, 4–40 °C, and pH 6–9. Comparative 16S rRNA analysis placed the strain within the genus Idiomarina , with its closest related type species being I. loihiensis , I. ramblicola , and I. abyssalis . Genomic analysis revealed the presence of several genes linked to halophilicity as well as unique metabolic pathways, including the ability to synthesize C5 and C10–C20 isoprenoids, which may contribute to the isolate’s survival in hypersaline conditions. The observed isoprenoid biosynthesis pathways suggest potential applications in various biotechnological fields, including the production of biofuels, pharmaceuticals, and other valuable chemicals. Levels of DNA-DNA relatedness, average nucleotide identity, and several phenotypic and chemotaxonomic markers clearly indicate that strain ATCH4 T represents a novel species of the genus Idiomarina , for which the designation Idiomarina aminovorans sp. nov. (type strain ATCH4 T = DSM 114475 = LMG 32710) is proposed.

An ice inhabiting bdelloid rotifer from North America - Lydia M. Dimattia; Naim Saglam; Ralph Saunders; Daniel H. Shain (Extremophiles, 2025)
Bdelloid rotifers are major components of zooplankton worldwide and have been reported in glacier ice in both Northern and Southern Hemispheres. Curiously, no reports of psychrophilic bdelloids have surfaced in North America despite exhaustive surveys of other ice-dwelling invertebrates, e.g., glacier ice worms. This distribution gap may be partially explained by a predator-prey relationship between these two animals, but the current study suggests that ice worms and bdelloids can co-inhabit at least some glacial ecosystems over geological time. Here we report the first ice-inhabiting bdelloid rotifer from North America, collected from the northern aspect of Mt. Deception, WA, USA. Nuclear and mitochondrial genotyping identified sister-species relationships within a clade of Nordic ice-dwelling bdelloids, and close evolutionary relationships with Antarctic/New Zealand specimens. Intrapopulation genetic divergences suggest that bdelloids arrived in North America near the onset of the Pleistocene (2.58 myr BP), but their circumpolar dispersal capabilities and robustness (e.g., freeze-thaw tolerance, ability to propagate at elevated temperatures and under extreme laboratory conditions) cannot rule out multiple transoceanic dispersal events throughout the Quaternary.

Structural characteristics and immunomodulatory activity of an exopolysaccharide from Antarctic Pseudoalteromonas sp. LP6-12-2 - Dezhi Wang; Han Li; Yu Zhao; Bailin Cong; Pengying Zhang (Extremophiles, 2025)

Draft genome sequence and comparative genomic analysis of Halomonas salifodinae strain A2 isolated from the Zapotitlán Salinas Valley, Puebla, Mexico - Alberto León-Lemus; Martha Martínez-García; Nathalie Cabirol; Jorge E. Campos; Alejandro Monsalvo-Reyes (Extremophiles, 2025)
In this study, we report the draft genome sequence of strain A2. The genome size was 3.8 Mbp, the GC content was 67.4%, and it was predicted to contain 3520 protein-coding genes, 62 tRNA genes, 8 rRNA genes, and 4 snRNA genes. Phylogenetic analysis of the 16S rRNA gene in different databases suggests that strain A2 belongs to Halomonas salifodinae . Also, Multilocus Sequence Typing analysis confirms that A2 is closely related to H. salifodinae . Phylogenomic of the core genes and comparative genomic analysis using the Average Nucleotide Identity, digital DNA-DNA Hybridization, Average Amino acid Identity, the Percentage of Conserved Proteins values indicators, and the Genome Taxonomy Database indicates that strain A2 is identified as H. salifodinae and suggest that this species has a closer phylogenetic relationship with the genus Bisbaumannia than with Halomonas . The pangenomic analysis of A2 against 100 reference genomes of described Halomonas and another related genus shows 136,122 genes that comprise the pangenome with 317 core genes, 3457 shell genes, 132,332 accessory genome genes, and 691 unique genes. A2 has 261 signature genes that it shares only with Bisbaumannia and Halomonas salifodinae. For strain A2 we found 29 genes for secretion systems, 23 genes for Na + and K + ion transport, 6 Biosynthetic Gene Clusters groups, a total of 12 genomic islands, an 8.2 kb gene prophage region, 15 regions associated with CRISPR and one CAS-TypeIF cas gene cluster region, 12 genes of biotechnological importance, 38 unique genes essential for adaptability and biotechnological relevance, as well as, 35 genes for the synthesis of compatible solutes. Comparative genomics analysis shows that strain A2 has multiple unique genetic features that could be useful for biotechnological applications. The result of this study places the species Halomonas salifodinae in a very close relationship with the genus Bisbaumannia than with Halomonas , so its reclassification to the genus Bisbaumannia is proposed for future validation.

Natranaerobius thermophilus: an anaerobic, polyextremophilic microorganism with unique properties and adaptive mechanisms - Noha M. Mesbah (Extremophiles, 2025)

Phosphate solubilization by filamentous fungi from Antarctic lichens and sediments - Adriely Vital de Souza Silva; Averlane Vieira da Silva; Adeildo Júnior de Oliveira; Rafaela Ferreira da Silva Costa; Rodrigo Paidano Alves; Luiz Henrique Rosa; Valéria Maia de Oliveira; Marcela Eugênia da Silva Cáceres; Janice Gomes Cavalcante; Sabrina Barros Cavalcante; Michel Rodrigo Zambrano Passarini; Aline Cavalcanti de Queiroz; et al. (Extremophiles, 2025)

Identification and characterization of a novel halolysin from Halostella sp. PRR32 with two C-terminal extensions - Yu Jin; Juntao Ke; Yuling Hao; Aodi Zhang; Han Wu; Yue Ding; Shengda Zhao; Jing Han; Aimin Liu; Shaoxing Chen (Extremophiles, 2025)

Microbial adaptations to acidic, nutrient- and metal-rich lakes in Aotearoa New Zealand - Laura Biessy; Jack Sissons; Joseph Kanyi Kihika; Susanna A. Wood; John K. Pearman (Extremophiles, 2025)

A colorful new reporter system to evaluate gene expression in the archaeon Haloferax volcanii - Sofía D. Frecha; María I. Giménez; Roberto A. Paggi; Rosana E. De Castro; Micaela Cerletti (Extremophiles, 2025)

Editorial - Garo Antranikian (Extremophiles, 2025)

Prospecting the biotechnological potential of culturable halophilic bacteria isolated from Provadia salt deposit (Bulgaria) near the oldest salt production and urban complex in Europe - Kaloyan Berberov; Nikolina Atanasova; Gabriela Teodosiu-Beleuţă; Ivanka Boyadzieva (Extremophiles, 2025)

Screening and community succession and functional prediction of high-efficiency degradation microbial communities for rice straw at low-temperature - Qiqi Fan; Yu Zhang; Jie Lian; Dong Liang; Jiang Yu; Xiaofei Liu; Na Zhang (Extremophiles, 2025)

Energetic investigations of Acidianus ambivalens metabolism during anaerobic sulfur reduction and comparisons to aerobic sulfur oxidation - Chloé E. Hart; Drew Gorman-Lewis (Extremophiles, 2025)

Adapting to salinity: structural dynamics of the DNA polymerase III beta subunit in Salinibacter ruber - Aveepsa Sengupta; Dhrubajyoti Das; Anisha Debnath; Yusuf Akhter; Ashutosh Kumar (Extremophiles, 2025)

From genes to nanotubes: exploring the UV-resistome in the Andean extremophile Exiguobacterium sp. S17 - Fátima Silvina Galván; Daniel Gonzalo Alonso-Reyes; Virginia Helena Albarracín (Extremophiles, 2025)

DNA methylation confers epigenetic changes in cold-adapted microorganisms in response to cold stress - Xuying Bu; Xufeng Dou; Zhe Chen; Lan Liu; Yuxia Mei; Min Ren (Extremophiles, 2025)

Extremophilic and common fungi in acid brines and their halite - Kathleen C. Benison; John E. Hallsworth; Polona Zalar; Miha Glavina; Nina Gunde-Cimerman (Extremophiles, 2025)

ABC-type salt tolerance transporter genes are abundant and mutually shared among the microorganisms of the hypersaline Sambhar Lake - Srikanta Pal; Raju Biswas; Abhijit Sar; Arijit Misra; Somasri Dam; Bomba Dam (Extremophiles, 2025)

Halobellus marinus sp. nov., Halobellus ordinarius sp. nov., Halobaculum rarum sp. nov., and Halorarum halobium sp. nov., halophilic archaea isolated from marine solar salt and a saline lake - Ling-Rui Zhu; Chidiebele Nwankwo; Jing Hou; Heng-Lin Cui (Extremophiles, 2025)

Genomic highlights of the phylogenetically unique halophilic purple nonsulfur bacterium, Rhodothalassium salexigens - Michael T. Madigan; Kelly S. Bender; Mary N. Parenteau; Yukihiro Kimura; Zheng-Yu Wang-Otomo; W. Matthew Sattley (Extremophiles, 2025)
Rhodothalassium ( Rts. ) salexigens is a halophilic purple nonsulfur bacterium and the sole species in the genus Rhodothalassium , which is itself the sole genus in the family Rhodothalassiaceae and sole family in the order Rhodothalassiales (class Alphaproteobacteria ). The genome of this phylogenetically unique phototroph comprises 3.35 Mb and is highly chimeric, with nearly half of its genes originating from families other than the Rhodothalassiaceae , many of which lack phototrophic species. Photosynthesis genes in Rts. salexigens are not arranged in a typical photosynthesis gene cluster but are scattered across the genome, suggesting an origin from horizontal transfers. Despite an encoded RuBisCO, autotrophy has not been observed in Rts. salexigens , and enzymes that oxidize common inorganic electron donors are not encoded. Phospholipid biosynthesis in Rts. salexigens is restricted, and phosphoglycerolipids are the only phospholipids present in its intracytoplasmic membranes. Rts. salexigens fixes nitrogen using a Mo-containing nitrogenase and uses ammonia despite previous results that indicated it was a glutamate auxotroph. Glycine betaine is the sole osmolyte in Rts. salexigens , and enzymes are encoded that facilitate both its uptake and its biosynthesis from glycine. The genomic data also support chemotactic swimming motility, growth over a range of salinities, and the production of membrane-strengthening hopanoids.

Mechanism of decolorization and degradation of direct brown D3G by a halo-thermophilic consortium - Wenying Wang; Zuotao Zhang; Meichen Sun; Chenlai Li; Mengdi Yan; Chongyang Wang (Extremophiles, 2025)

Insights into the dynamics and evolution of Rummeliibacillus stabekisii prophages in extreme environments: from Antarctic soil to spacecraft floors - Caroline Martiniuc; Igor Taveira; Fernanda Abreu; Anderson S. Cabral; Rodolfo Paranhos; Lucy Seldin; Diogo Jurelevicius (Extremophiles, 2025)

Unraveling the effects of polyhydroxyalkanoates accumulation in Pseudomonas extremaustralis growth and survival under different pH conditions - María Gabriela Brito; Nancy I. López; Laura J. Raiger Iustman (Extremophiles, 2025)

Variations on a theme: non-canonical DUF3494 ice-binding proteins - James A. Raymond (Extremophiles, 2025)

Characterization of a family IV esterase from extremely halophilic archaeon Haloarcula japonica - Hiromichi Kato; Shota Ambai; Fumiya Ikeda; Koji Abe; Satoshi Nakamura; Rie Yatsunami (Extremophiles, 2025)
The novel esterase gene lipP1 , which encodes HjEstP1, was discovered in the genome of the extremely halophilic archaeon Haloarcula japonica . A homology search and sequence alignment revealed that HjEstP1 is a member of family IV esterases with conserved GXSXG and HGGG motifs. lipP1 was expressed in its parental strain, and recombinant HjEstP1 was purified and characterized. Optimal pH and temperature of HjEstP1 were 6.0 and > 60 °C, respectively. HjEstP1 showed higher activity with increasing NaCl concentration, and optimal NaCl concentration was > 4.5 M. Furthermore, HjEstP1 preferentially hydrolyzed p NP and glycerol esters with short chain fatty acids. To our knowledge, this is the first report of an esterase from an extremely halophilic archaeon obtained via homologous expression.

Biological treatment of methyl orange dye and textile wastewater using halo-alkaliphilic bacteria under highly alkaline conditions - Gunisha Wadhawan; Anshu Gupta (Extremophiles, 2025)

Lawrence I. (Larry) Hochstein a researcher dedicated to halophilic microorganisms of all types and environments - Russell H. Vreeland; Aharon Oren; Antonio Ventosa (Extremophiles, 2025)

Characterization of prokaryotic communities from Italian super-heated fumaroles - Alessia Rossi; Irene Barbagli; Claudia Vannini (Extremophiles, 2025)

Increase of ATP synthesis and amino acids absorption contributes to cold adaptation in Antarctic bacterium Poseidonibacter antarcticus SM1702T - Wen-Yue Xu; Sha-Sha Liu; Xiao-Han Guo; Peng Wang; Chun-Yang Li; Li Liao; Qi-Long Qin (Extremophiles, 2025)

Microbial and mineralogical characterization of the alkaline Chae Son hot spring, Northern Thailand - C. Sriaporn; S. Komonjinda; N. Klayposri; K. Phinyo; J. Pekkoh; S. Awiphan; T. Chanprom (Extremophiles, 2025)

Insights into the role of cyclopropane fatty acid synthase (CfaS) from extreme acidophile in bacterial defense against environmental acid stress - Wenbo Hu; Xingyu Huo; Tengfei Ma; Zhigang Li; Tianyou Yang; Hailin Yang; Shoushuai Feng (Extremophiles, 2025)

Genome-based classification of Halobellus rubicundus sp. nov., a novel extremely halophilic archaeon isolated from a Korean solar saltern - Chi Young Hwang; Eui-Sang Cho; In-Tae Cha; Ki-Eun Lee; Eun-Young Lee; Myung-Ji Seo (Extremophiles, 2024)

Sugar alcohol degradation in Archaea: uptake and degradation of mannitol and sorbitol in Haloarcula hispanica - Marius Ortjohann; Peter Schönheit (Extremophiles, 2024)
The halophilic archaeon Haloarcula hispanica utilizes the sugar alcohols mannitol and sorbitol as carbon and energy sources. Genes, enzymes, and transcriptional regulators involved in uptake and degradation of these sugar alcohols were identified by growth experiments with deletion mutants and enzyme characterization. It is shown that both mannitol and sorbitol are taken up via a single ABC transporter of the CUT1 transporter family. Then, mannitol and sorbitol are oxidized to fructose by two distinct dehydrogenases. Fructose is further phosphorylated to fructose-1-phosphate by a haloarchaeal ketohexokinase, providing the first evidence for a physiological function of ketohexokinase in prokaryotes. Finally, fructose-1-phosphate is phosphorylated via fructose-1-phosphate kinase to fructose-1,6-bisphosphate, which is cleaved to triosephosphates by a Class I fructose-1,6-bisphosphate aldolase. Two distinct transcriptional regulators, acting as activators, have been identified: an IclR-like regulator involved in activating genes for sugar alcohol uptake and oxidation to fructose, and a GfcR-like regulator that likely activates genes involved in the degradation of fructose to pyruvate. This is the first comprehensive analysis of a sugar alcohol degradation pathway in Archaea.

Genome‑based classification of the family Natrialbaceae and description of four novel halophilic archaea from three saline lakes and a saline-alkaline land - Xin-Yue Dong; Ya-Ling Mao; Qing-Ke Zhang; Ling-Rui Zhu; Jing Hou; Heng-Lin Cui (Extremophiles, 2024)

Diversity, distribution and phytotoxic and anti-Trypanosoma activities of cultivable fungi associated with Magellan sub-Antarctic strait and Maritime Antarctic macroalgae - Matheus Souto de Freitas; Camila Rodrigues de Carvalho; Franciane Maria Pellizzari; Andres Omar Mansilla; Johanna Marambio; Tânia Maria de Almeida Alves; Silvane Maria Fonseca Murta; Carlos Leomar Zani; Peter Convey; Luiz Henrique Rosa (Extremophiles, 2024)

Utilisation of acid-tolerant bacteria for base metal recovery under strongly acidic conditions - Chikara Takano; Kazunori Nakashima; Satoru Kawasaki; Hideki Aoyagi (Extremophiles, 2024)

Identification of a thermostable L-asparaginase from Pyrococcus yayanosii CH1 and its application in the reduction of acrylamide - Dawei Ni; Wei Xu; Wenli Zhang; Wanmeng Mu (Extremophiles, 2024)

Molecular diversity of green-colored microbial mats from hot springs of northern Japan - Yangtsho Gyaltshen; Yuu Ishii; Sophie Charvet; Eleanor Goetz; Shinichiro Maruyama; Eunsoo Kim (Extremophiles, 2024)

Molecular basis of hyper-thermostability in the thermophilic archaeal aldolase MfnB - Rosie M. A. Maddock; Carl O. Marsh; Samuel T. Johns; Lynden D. Rooms; Phillip W. Duke; Marc W. van der Kamp; James E. M. Stach; Paul R. Race (Extremophiles, 2024)
Methanogenic archaea are chemolithotrophic prokaryotes that can reduce carbon dioxide with hydrogen gas to form methane. These microorganisms make a significant contribution to the global carbon cycle, with methanogenic archaea from anoxic environments estimated to contribute > 500 million tons of global methane annually. Archaeal methanogenesis is dependent on the methanofurans; aminomethylfuran containing coenzymes that act as the primary C 1 acceptor molecule during carbon dioxide fixation. Although the biosynthetic pathway to the methanofurans has been elucidated, structural adaptations which confer thermotolerance to Mfn enzymes from extremophilic archaea are yet to be investigated. Here we focus on the methanofuran biosynthetic enzyme MfnB, which catalyses the condensation of two molecules of glyceralde-3-phosphate to form 4‑(hydroxymethyl)-2-furancarboxaldehyde-phosphate. In this study, MfnB enzymes from the hyperthermophile Methanocaldococcus jannaschii and the mesophile Methanococcus maripaludis have been recombinantly overexpressed and purified to homogeneity. Thermal unfolding studies, together with steady-state kinetic assays, demonstrate thermoadaptation in the M. jannaschii enzyme. Molecular dynamics simulations have been used to provide a structural explanation for the observed properties. These reveal a greater number of side chain interactions in the M. jannaschii enzyme, which may confer protection from heating effects by enforcing spatial residue constraints.

Multifunctionality of a low-specificity L-threonine aldolase from the hyperthermophile Thermotoga maritima - Tetsuya Miyamoto; Fugo Kobayashi; Konan Emori; Kumiko Sakai-Kato (Extremophiles, 2024)

Genomic signatures of cold adaptation in the family Colwelliaceae - Anais Gentilhomme; Charles Sweet; Gwenn M. M. Hennon; R. Eric Collins (Extremophiles, 2024)

Diversity of lichen mycobionts and photobionts and their relationships in the Ny-Ålesund region (Svalbard, High Arctic) - Xiufei Chen; Jianju Feng; Liyan Yu; Tao Zhang (Extremophiles, 2024)

The Tet-on system for controllable gene expression in the rock-inhabiting black fungus Knufia petricola - Eileen A. Erdmann; Antonia K. M. Brandhorst; Anna A. Gorbushina; Julia Schumacher (Extremophiles, 2024)
Knufia petricola is a black fungus that colonizes sun-exposed surfaces as extreme and oligotrophic environments. As ecologically important heterotrophs and biofilm-formers on human-made surfaces, black fungi form one of the most resistant groups of biodeteriorating organisms. Due to its moderate growth rate in axenic culture and available protocols for its transformation and CRISPR/Cas9-mediated genome editing, K. petricola is used for studying the morpho-physiological adaptations shared by extremophilic and extremotolerant black fungi. In this study, the bacteria-derived tetracycline (TET)-dependent promoter (Tet-on) system was implemented to enable controllable gene expression in K. petricola . The functionality i.e., the dose-dependent inducibility of TET-regulated constructs was investigated by using GFP fluorescence, pigment synthesis (melanin and carotenoids) and restored uracil prototrophy as reporters. The newly generated cloning vectors containing the Tet-on construct, and the validated sites in the K. petricola genome for color-selectable or neutral insertion of expression constructs complete the reverse genetics toolbox. One or multiple genes can be expressed on demand from different genomic loci or from a single construct by using 2A self-cleaving peptides, e.g., for localizing proteins and protein complexes in the K. petricola cell or for using K. petricola as host for the expression of heterologous genes.

Comparative analysis of cyanobacterial communities in gypsum outcrops: insights from sites in Israel and Poland - Kateřina Němečková; Jan Mareš; Filip Košek; Adam Culka; Jan Dudák; Veronika Tymlová; Jan Žemlička; Jan Jehlička (Extremophiles, 2024)

Development of a defined medium for the heterotrophic cultivation of Metallosphaera sedula - Viktor Laurin Sedlmayr; Maximilian Luger; Ernst Pittenauer; Martina Marchetti-Deschmann; Laura Kronlachner; Andreas Limbeck; Philipp Raunjak; Julian Quehenberger; Oliver Spadiut (Extremophiles, 2024)
The heterotrophic cultivation of extremophilic archaea still heavily relies on complex media. However, complex media are associated with unknown composition, high batch-to-batch variability, potential inhibiting and interfering components, as well as regulatory challenges, hampering advancements of extremophilic archaea in genetic engineering and bioprocessing. For Metallosphaera sedula , a widely studied organism for biomining and bioremediation and a potential production host for archaeal ether lipids, efforts to find defined cultivation conditions have still been unsuccessful. This study describes the development of a novel chemically defined growth medium for M. sedula . Initial experiments with commonly used complex casein-derived media sources deciphered Casamino Acids as the most suitable foundation for further development. The imitation of the amino acid composition of Casamino Acids in basal Brock medium delivered the first chemically defined medium. We could further simplify the medium to 5 amino acids based on the respective specific substrate uptake rates. This first defined cultivation medium for M. sedula allows advanced genetic engineering and more controlled bioprocess development approaches for this highly interesting archaeon.

RNase R vs. PNPase: selecting the best-suited exoribonuclease for environmental adaptation - Theetha L. Pavankumar (Extremophiles, 2024)

Effects of temperature, chloride and perchlorate salt concentration on the metabolic activity of Deinococcus radiodurans - Eftychia Symeonidou; Uffe Gråe Jørgensen; Morten Bo Madsen; Anders Priemé (Extremophiles, 2024)
The extremophile bacterium Deinococcus radiodurans is characterized by its ability to survive and sustain its activity at high levels of radiation and is considered an organism that might survive in extraterrestrial environments. In the present work, we studied the combined effects of temperature and chlorine-containing salts, with focus on perchlorate salts which have been detected at high concentrations in Martian regolith, on D. radiodura ns activity (CO 2 production rates) and viability after incubation in liquid cultures for up to 30 days. Reduced CO 2 production capacity and viability was observed at high perchlorate concentrations (up to 10% w/v) during incubation at 0 or 25 °C. Both the metabolic activity and viability were reduced as the perchlorate and chloride salt concentration increased and temperature decreased, and an interactive effect of temperature and salt concentration on the metabolic activity was found. These results indicate the ability of D. radiodurans to remain metabolically active and survive in low temperature environments rich in perchlorate.

Characterization of carotenoids extracted from Haloferax larsenii NCIM 5678 isolated from Pachpadra salt lake, Rajasthan - Pardeep Sheokand; Santosh Kumar Tiwari (Extremophiles, 2024)

Bioenergetic characterization of hyperthermophilic archaean Methanocaldococcus sp. FS406-22 - Addien C. Wray; Autum R. Downey; Andrea A. Nodal; Katherine K. Park; Drew Gorman-Lewis (Extremophiles, 2024)

Untangling the adaptive strategies of thermophilic bacterium Anoxybacillus rupiensis TPH1 under low temperature - Aditi Mishra; Sindhunath Chakraborty; Tameshwar Prasad Jaiswal; Samujjal Bhattacharjee; Shreya Kesarwani; Arun Kumar Mishra; Satya Shila Singh (Extremophiles, 2024)

Enzymes and biosurfactants of industrial interest produced by culturable fungi present in sediments of Boeckella Lake, Hope Bay, north-east Antarctic Peninsula - Elisa Amorim Amâncio Teixeira; Láuren Machado Drumond de Souza; Rosemary Vieira; Juan Manuel Lirio; Silvia Herminda Coria; Peter Convey; Carlos Augusto Rosa; Luiz Henrique Rosa (Extremophiles, 2024)

Mineralogical and microbial characterization of alkali hot spring microbial mats and deposits in Pong Dueat Pa Pae hot spring, Northern Thailand - C. Sriaporn; S. Komonjinda; S. Awiphan; S. Santitharangkun; C. Banjongprasert; M. Osathanunkul; B. Ramsiri (Extremophiles, 2024)

Halobacterium yunchengense sp. nov., Natronomonas amylolytica sp. nov., Halorientalis halophila sp. nov., Halobellus salinisoli sp. nov., halophilic archaea isolated from a saline lake and inland saline soil - Ling Cui; Yao Hu; Xin-Xin Li; Xue Ma; Mu Cheng; Shun Tan; Jing Hou; Heng-Lin Cui (Extremophiles, 2024)

Characterization and biological activities of a novel exopolysaccharide produced from Geobacillus thermodenitrificans HBB 111 strain - Mehmet Aytar; Gamze Başbülbül; Deniz Aktaş Uygun (Extremophiles, 2024)

Extremophiles in a changing world - D. A. Cowan; S. V. Albers; G. Antranikian; H. Atomi; B. Averhoff; M. Basen; A. J. M. Driessen; M. Jebbar; Z. Kelman; M. Kerou; J. Littlechild; V. Müller; et al. (Extremophiles, 2024)
Extremophiles and their products have been a major focus of research interest for over 40 years. Through this period, studies of these organisms have contributed hugely to many aspects of the fundamental and applied sciences, and to wider and more philosophical issues such as the origins of life and astrobiology. Our understanding of the cellular adaptations to extreme conditions (such as acid, temperature, pressure and more), of the mechanisms underpinning the stability of macromolecules, and of the subtleties, complexities and limits of fundamental biochemical processes has been informed by research on extremophiles. Extremophiles have also contributed numerous products and processes to the many fields of biotechnology, from diagnostics to bioremediation. Yet, after 40 years of dedicated research, there remains much to be discovered in this field. Fortunately, extremophiles remain an active and vibrant area of research. In the third decade of the twenty-first century, with decreasing global resources and a steadily increasing human population, the world’s attention has turned with increasing urgency to issues of sustainability. These global concerns were encapsulated and formalized by the United Nations with the adoption of the 2030 Agenda for Sustainable Development and the presentation of the seventeen Sustainable Development Goals (SDGs) in 2015. In the run-up to 2030, we consider the contributions that extremophiles have made, and will in the future make, to the SDGs.

Metagenomic profiling of halites from the Atacama Desert: an extreme environment with natural perchlorate does not promote high diversity of perchlorate reducing microorganisms - Santiago Cadena; Daniel Cerqueda-García; María Magdalena Uribe-Flores; Sandra I. Ramírez (Extremophiles, 2024)

Comparative molecular dynamics simulations provided insights into the mechanisms of cold-adaption of alginate lyases from the PL7 family - Fei Bian; Xiao-Yue Liang; Meng Wang; Zhong-Zhi Sun; Bin-Bin Xie (Extremophiles, 2024)

Fungal diversity present in snow sampled in summer in the north-west Antarctic Peninsula and the South Shetland Islands, Maritime Antarctica, assessed using metabarcoding - Graciéle Cunha Alves de Menezes; Fabyano A. C. Lopes; Karita C. R. Santos; Micheline C. Silva; Peter Convey; Paulo E. A. S. Câmara; Luiz H. Rosa (Extremophiles, 2024)

Genome-based classification of the family Haloferacaceae and description of five novel species of Halobaculum - Shun Tan; Ling-Rui Zhu; Qing-Ke Zhang; Xin-Yue Dong; Jing Hou; Heng-Lin Cui (Extremophiles, 2024)

Antarctic marine sediment as a source of filamentous fungi-derived antimicrobial and antitumor compounds of pharmaceutical interest - Karine Fernandes Camacho; Layssa de Melo Carlos; Suzan Prado Fernandes Bernal; Valéria M. de Oliveira; Jorge Luiz Maria Ruiz; Júlia Ronzella Ottoni; Rosemary Vieira; Arthur Neto; Luiz Henrique Rosa; Michel Rodrigo Zambrano Passarini (Extremophiles, 2024)

Diversity and enzymatic, biosurfactant and phytotoxic activities of culturable Ascomycota fungi present in marine sediments obtained near the South Shetland Islands, maritime Antarctica - Mayanne Karla da Silva; Débora Luiza Costa Barreto; Rosemary Vieira; Arthur Ayres Neto; Fábio Soares de Oliveira; Peter Convey; Carlos Augusto Rosa; Alysson Wagner Fernandes Duarte; Luiz Henrique Rosa (Extremophiles, 2024)

Astrobiological implications of the organic and inorganic cyanide utilization by a novel Antarctic hyperthermophilic Pyrococcus strain - Patricio A. Uribe-Redlich; Maximiliano J. Amenabar; Geraldine V. Dennett; Jenny M. Blamey (Extremophiles, 2024)

A novel alkane monooxygenase evolved from a broken piece of ribonucleotide reductase in Geobacillus kaustophilus HTA426 isolated from Mariana Trench - Tanasap Nithimethachoke; Chanita Boonmak; Masaaki Morikawa (Extremophiles, 2024)
We have accidentally found that a thermophilic Geobacillus kaustophilus HTA426 is capable of degrading alkanes although it has no alkane oxygenating enzyme genes. Our experimental results revealed that a putative ribonucleotide reductase small subunit Gk R2loxI (GK2771) gene encodes a novel heterodinuclear Mn–Fe alkane monooxygenase/hydroxylase. Gk R2loxI protein can perform two-electron oxidations similar to homonuclear diiron bacterial multicomponent soluble methane monooxygenases. This finding not only answers a long-standing question about the substrate of the R2lox protein clade, but also expands our understanding of the vast diversity and new evolutionary lineage of the bacterial alkane monooxygenase/hydroxylase family.

Physiological characterization of polyextremotolerant yeasts from cold environments of Patagonia - Rubí A. Duo Saito; Martín Moliné; Virginia de Garcia (Extremophiles, 2024)

In Memoriam: Mosè Rossi (1938–2023) - Marco Moracci; Beatrice Cobucci-Ponzano; Giuseppe Perugino; Garabed Antranikian (Extremophiles, 2024)

Biochemical and in silico structural characterization of a cold-active arginase from the psychrophilic yeast, Glaciozyma antarctica PI12 - Nik Yusnoraini Yusof; Doris Huai Xia Quay; Shazilah Kamaruddin; Mohd Anuar Jonet; Rosli Md Illias; Nor Muhammad Mahadi; Mohd Firdaus-Raih; Farah Diba Abu Bakar; Abdul Munir Abdul Murad (Extremophiles, 2024)

Unraveling the multiplicity of geranylgeranyl reductases in Archaea: potential roles in saturation of terpenoids - Alka Rao; Arnold J. M. Driessen (Extremophiles, 2024)
The enzymology of the key steps in the archaeal phospholipid biosynthetic pathway has been elucidated in recent years. In contrast, the complete biosynthetic pathways for proposed membrane regulators consisting of polyterpenes, such as carotenoids, respiratory quinones, and polyprenols remain unknown. Notably, the multiplicity of geranylgeranyl reductases (GGRs) in archaeal genomes has been correlated with the saturation of polyterpenes. Although GGRs, which are responsible for saturation of the isoprene chains of phospholipids, have been identified and studied in detail, there is little information regarding the structure and function of the paralogs. Here, we discuss the diversity of archaeal membrane-associated polyterpenes which is correlated with the genomic loci, structural and sequence-based analyses of GGR paralogs.

Correction: Limits to the three domains of life: lessons from community assembly along an Antarctic salinity gradient - Xiaoben Jiang; David J. Van Horn; Jordan G. Okie; Heather N. Buelow; Egbert Schwartz; Daniel R. Colman; Kelli L. Feeser; Cristina D. Takacs-Vesbach (Extremophiles, 2024)

Effects of small heat shock proteins from thermotolerant bacteria on the stress resistance of Escherichia coli to temperature, pH, and hyperosmolarity - Yu Sato; Kenji Okano; Kohsuke Honda (Extremophiles, 2024)
Small heat shock proteins (HSPs), such as HSP20, represent cellular thermal resistance mechanisms, to avoid protein aggregation at elevated temperatures. Recombinantly expressed HSP20s serve as a molecular tool for improving the tolerance of living cells to various physical and chemical stressors. Here, we aimed to heterologously express 18 HSP20s from 12 thermotolerant bacteria in Escherichia coli and evaluate their effects on various physical and chemical cellular stresses. Seventeen HSP20s were successfully expressed as soluble proteins. Recombinant E. coli cells were subjected to heat, cold, acidic, alkaline, and hyperosmolar stress to evaluate the effects of HSP20 proteins on stress resistance. Notably, the overexpression of 15 HSP20s enhanced the stress resistance of E. coli compared to that of the control strain . In particular, HSPs from Tepidimonas sediminis and Oceanithermus profundus improved the stress tolerance of E. coli under all tested conditions. In addition, E. coli harboring HSP20 from T. sediminis retained cell viability even after heat treatment at 52 °C for 5 days. To our knowledge, this is the first report of E. coli tolerance to prolonged (> 100 h) high-temperature stress. These findings indicate the potential of thermotolerant HSPs as molecular tools for improving stress tolerance in E. coli .

Efficient flocculation pretreatment of coal gasification wastewater by halophilic bacterium Halovibrio variabilis TG-5 - Xin Sun; Gangsheng Zhang; Yamin Shi; Daling Zhu; Lin Cheng (Extremophiles, 2024)

Genome-based taxonomy of genera Haloarcula and Halomicroarcula, and description of six novel species of Haloarcula - Xue Ma; Yao Hu; Xin-Xin Li; Shun Tan; Mu Cheng; Jing Hou; Heng-Lin Cui (Extremophiles, 2024)

Comparative genomics reveals probable adaptations for xylose use in Thermoanaerobacterium saccharolyticum - Mateus Bernabe Fiamenghi; Juliana Silveira Prodonoff; Guilherme Borelli; Marcelo Falsarella Carazzolle; Gonçalo Amarante Guimaraes Pereira; Juliana José (Extremophiles, 2024)

Metataxonomy of acid mine drainage microbiomes from the Santa Catarina Carboniferous Basin (Southern Brazil) - Estácio Jussie Odisi; Robert Cardoso de Freitas; Diego Serrasol do Amaral; Saulo Britto da Silva; Marcus Adonai Castro da Silva; William de Oliveira Sant Ana; André Oliveira de Souza Lima; Leonardo Rubi Rörig (Extremophiles, 2024)

Differential cellular localization of DNA gyrase and topoisomerase IB in response to DNA damage in Deinococcus radiodurans - Shruti Mishra; Himani Tewari; Reema Chaudhary; Hari S.Misra; Swathi Kota (Extremophiles, 2024)

Insights into the rapid metabolism of Geobacillus sp. LC300: unraveling metabolic requirements and optimal growth conditions - Emil Ljungqvist; Jeanett Daga-Quisbert; Antonius van Maris; Martin Gustavsson (Extremophiles, 2024)
This study investigated the metabolism of Geobacillus sp. LC300, a promising biorefinery host organism with high substrate utilization rates. A new defined medium was designed and tested that allows for exponential growth to elevated cell densities suitable for quantitative physiological studies. Screening of the metabolic requirements of G. sp. LC300 revealed prototrophy for all essential amino acids and most vitamins and only showed auxotrophy for vitamin B12 and biotin. The effect of temperature and pH on growth rate was investigated, adjusting the optimal growth temperature to several degrees lower than previously reported. Lastly, studies on carbon source utilization revealed a capability for fast growth on several common carbon sources, including monosaccharides, oligosaccharides, and polysaccharides, and the highest ever reported growth rate in defined medium on glucose (2.20 h −1 ) or glycerol (1.95 h −1 ). These findings provide a foundation for further exploration of G. sp. LC300's physiology and metabolic regulation, and its potential use in bioproduction processes.

Mining thermophiles for biotechnologically relevant enzymes: evaluating the potential of European and Caucasian hot springs - Christin Burkhardt; Leon Baruth; Neele Meyer-Heydecke; Barbara Klippel; Armine Margaryan; Ani Paloyan; Hovik H. Panosyan; Garabed Antranikian (Extremophiles, 2024)
The development of sustainable and environmentally friendly industrial processes is becoming very crucial and demanding for the rapid implementation of innovative bio-based technologies. Natural extreme environments harbor the potential for discovering and utilizing highly specific and efficient biocatalysts that are adapted to harsh conditions. This review focuses on extremophilic microorganisms and their enzymes (extremozymes) from various hot springs, shallow marine vents, and other geothermal habitats in Europe and the Caucasus region. These hot environments have been partially investigated and analyzed for microbial diversity and enzymology. Hotspots like Iceland, Italy, and the Azores harbor unique microorganisms, including bacteria and archaea. The latest results demonstrate a great potential for the discovery of new microbial species and unique enzymes that can be explored for the development of Circular Bioeconomy. Different screening approaches have been used to discover enzymes that are active at extremes of temperature (up 120 °C), pH (0.1 to 11), high salt concentration (up to 30%) as well as activity in the presence of solvents (up to 99%). The majority of published enzymes were revealed from bacterial or archaeal isolates by traditional activity-based screening techniques. However, the latest developments in molecular biology, bioinformatics, and genomics have revolutionized life science technologies. Post-genomic era has contributed to the discovery of millions of sequences coding for a huge number of biocatalysts. Both strategies, activity- and sequence-based screening approaches, are complementary and contribute to the discovery of unique enzymes that have not been extensively utilized so far.

Phosphonate consumers potentially contributing to methane production in Brazilian soda lakes - C. R. Carvalho; B. C. E. Souza; W. Bieluczyk; Y. B. Feitosa; E. Delbaje; P. B. Camargo; S. M. Tsai; Marli F. Fiore (Extremophiles, 2024)

Investigating non-fungal eukaryotic diversity in snow in the Antarctic Peninsula region using DNA metabarcoding - Paulo E. A. S. Câmara; Graciéle C. A. de Menezes; Fabyano A. C. Lopes; Thiago da Silva Paiva; Micheline Carvalho-Silva; Peter Convey; Eduardo T. Amorim; Luiz H. Rosa (Extremophiles, 2024)

Lignocellulolytic extremozymes and their biotechnological applications - Nikita Sharma; Aditi Agarwal; Ananya Bijoy; Sunidhi Pandit; Rakesh Kumar Sharma (Extremophiles, 2024)

Halorubrum hochsteinianum sp. nov., an ancient haloarchaeon from a natural experiment - Russell H. Vreeland; Ya-Ping Sun; Bei-Bei Wang; Jing Hou; Heng-Lin Cui (Extremophiles, 2024)

Disorder and amino acid composition in proteins: their potential role in the adaptation of extracellular pilins to the acidic media, where Acidithiobacillus thiooxidans grows - Edgar D. Páez-Pérez; Araceli Hernández-Sánchez; Elvia Alfaro-Saldaña; J. Viridiana García-Meza (Extremophiles, 2023)

Production of poly (3-hydroxybutyrate) and extracellular polymeric substances from glycerol by the acidophile Acidiphilium cryptum - Ernesto González; Camila Zuleta; Guiselle Zamora; Nataly Maturana; Belén Ponce; María Virginia Rivero; Alberto Rodríguez; Juan Pablo Soto; Felipe Scott; Álvaro Díaz-Barrera (Extremophiles, 2023)

Properties of the extracellular alkaline inulinase produced by haloalkaliphilic phototrophic bacteria Ectothiorodospirea mobilis - Levon Markosyan; Arevik Vardanyan (Extremophiles, 2023)

Pyrofollis japonicus gen. nov. sp. nov., a novel member of the family Pyrodictiaceae isolated from the Iheya North hydrothermal field - Urara Miyazaki; Masaru Sanari; Akihiro Tame; Masaaki Kitajima; Akihiro Okamoto; Shigeki Sawayama; Junichi Miyazaki; Ken Takai; Satoshi Nakagawa (Extremophiles, 2023)

Extremophilic microbial metabolism and radioactive waste disposal - Sarah Jane Butterworth; Franky Barton; Jonathan Richard Lloyd (Extremophiles, 2023)
Decades of nuclear activities have left a legacy of hazardous radioactive waste, which must be isolated from the biosphere for over 100,000 years. The preferred option for safe waste disposal is a deep subsurface geological disposal facility (GDF). Due to the very long geological timescales required, and the complexity of materials to be disposed of (including a wide range of nutrients and electron donors/acceptors) microbial activity will likely play a pivotal role in the safe operation of these mega-facilities. A GDF environment provides many metabolic challenges to microbes that may inhabit the facility, including high temperature, pressure, radiation, alkalinity, and salinity, depending on the specific disposal concept employed. However, as our understanding of the boundaries of life is continuously challenged and expanded by the discovery of novel extremophiles in Earth’s most inhospitable environments, it is becoming clear that microorganisms must be considered in GDF safety cases to ensure accurate predictions of long-term performance. This review explores extremophilic adaptations and how this knowledge can be applied to challenge our current assumptions on microbial activity in GDF environments. We conclude that regardless of concept, a GDF will consist of multiple extremes and it is of high importance to understand the limits of polyextremophiles under realistic environmental conditions.

Structure/function studies of the NAD+-dependent DNA ligase from the poly-extremophile Deinococcus radiodurans reveal importance of the BRCT domain for DNA binding - Andreia Fernandes; Adele Williamson; Pedro M. Matias; Elin Moe (Extremophiles, 2023)
Bacterial NAD + -dependent DNA ligases (LigAs) are enzymes involved in replication, recombination, and DNA-repair processes by catalyzing the formation of phosphodiester bonds in the backbone of DNA. These multidomain proteins exhibit four modular domains, that are highly conserved across species, with the BRCT (breast cancer type 1 C-terminus) domain on the C-terminus of the enzyme. In this study, we expressed and purified both recombinant full-length and a C-terminally truncated LigA from Deinococcus radiodurans (DrLigA and DrLigA∆BRCT) and characterized them using biochemical and X-ray crystallography techniques. Using seeds of DrLigA spherulites, we obtained ≤ 100 µm plate crystals of DrLigA∆BRCT. The crystal structure of the truncated protein was obtained at 3.4 Å resolution, revealing DrLigA∆BRCT in a non-adenylated state. Using molecular beacon-based activity assays, we demonstrated that DNA ligation via nick sealing remains unaffected in the truncated DrLigA∆BRCT. However, DNA-binding assays revealed a reduction in the affinity of DrLigA∆BRCT for dsDNA. Thus, we conclude that the flexible BRCT domain, while not critical for DNA nick-joining, plays a role in the DNA binding process, which may be a conserved function of the BRCT domain in LigA-type DNA ligases.

Genetic engineering of low-temperature polyhydroxyalkanoate production by Acidovorax sp. A1169, a psychrophile isolated from a subglacial outflow - Jakub Grzesiak; Jan Gawor; Małgorzata Marta Rogala; Xenie Kouřilová; Stanislav Obruča (Extremophiles, 2023)
In recent years, extremophilic microorganisms have been employed as producers of the microbial bioplastics polyhydroxyalkanoates (PHA), which are of great biotechnological value. Nevertheless, cold-loving or psychrophilic (cryophilic) bacteria have been neglected in this regard. Here, we present an investigation of the Arctic glacier-derived PHA producer Acidovorax sp. A1169. Biolog GEN III Microplates were used as a screening tool to identify the most suitable carbon substrate concerning PHA synthesis. The strain produced homopolymer poly(3-hydroxybutyrate) (PHB) most efficiently (2 g/L) at a temperature of 15 °C when supplied with fructose or mannitol as carbon sources with a substantial decrease of PHB biosynthesis at 17.5 °C. The PHB yield did not increase considerably or even decreased when carbon source concentration exceeded 10 g/L hinting that the strain is oligotrophic in nature. The strain was also capable of introducing 3-hydroxyvalerate (3HV) into the polymer structure, which is known to improve PHA thermoplastic properties. This is the first investigation providing insight into a PHA biosynthesis process by means of a true psychrophile, offering guidelines on polar-region bacteria cultivation, production of PHA and also on the methodology for genetic engineering of psychrophiles.

Vertical segregation and phylogenetic characterization of archaea and archaeal ammonia monooxygenase gene in the water column of the western Arctic Ocean - Puthiya Veettil Vipindas; Thajudeen Jabir; Siddarthan Venkatachalam; Eun Jin Yang; Anand Jain; Kottekkatu Padinchati Krishnan (Extremophiles, 2023)

Correction: Quantitative evaluation of endogenous reference genes for ddPCR under salt stress using a moderate halophile - Qinghua Xing; Noha M. Mesbah; Haisheng Wang; Jun Li; Baisuo Zhao (Extremophiles, 2023)

The genus Anoxybacillus: an emerging and versatile source of valuable biotechnological products - Deisiane Fernanda da Rosa; Alexandre José Macedo (Extremophiles, 2023)

Functional expression of an antimicrobial peptide, belonging to halocin C8 family, from Natrinema sp. RNS21 in Escherichia coli - Chang Ho Ri; Song Ryong Li; Chon Il Paek; Yu Sin Kim (Extremophiles, 2023)

Molecular evolution steered structural adaptations in the DNA polymerase III α subunit of halophilic bacterium Salinibacter ruber - Aveepsa Sengupta; Kunwali Das; Nidhi Jha; Yusuf Akhter; Ashutosh Kumar (Extremophiles, 2023)

Genomic basis for the unique phenotype of the alkaliphilic purple nonsulfur bacterium Rhodobaca bogoriensis - Michael T. Madigan; Kelly S. Bender; Sophia A. Sanguedolce; Mary N. Parenteau; Marisa H. Mayer; Yukihiro Kimura; Zheng-Yu Wang-Otomo; W. Matthew Sattley (Extremophiles, 2023)

Recombinant expression and characterization of a new laccase, bioinformatically identified, from the Antarctic thermophilic bacterium Geobacillus sp. ID17 - Rodrigo Cortés-Antiquera; Sebastián L. Márquez; Giannina Espina; Jorge Sánchez-SanMartín; Jenny M. Blamey (Extremophiles, 2023)

Survival of Icelandic airborne microbes towards simulated atmospheric stress factors - Aurélien Daussin; Pauline Vannier; Émilien Mater; Tina Šantl-Temkiv; Charles Cockell; Viggó Þór Marteinsson (Extremophiles, 2023)

Selection of Antarctic yeasts as gray mold biocontrol agents in strawberry - Eskálath Morganna Silva Ferreira; Gabriela Garmendia; Vívian Nicolau Gonçalves; Juliana Fonseca Moreira da Silva; Luiz Henrique Rosa; Silvana Vero; Raphael Sanzio Pimenta (Extremophiles, 2023)

Salinilacihabitans rarus gen. nov., sp. nov., Natrononativus amylolyticus gen. nov., sp. nov., Natronobeatus ordinarius gen. nov., sp. nov., and Halovivax gelatinilyticus sp. nov., halophilic archaea, isolated from a salt lake and soda lakes - Xin-Xin Li; Shun Tan; Mu Cheng; Yao Hu; Xue Ma; Jing Hou; Heng-Lin Cui (Extremophiles, 2023)

Identification and genome-wide analysis provide insights into the genetic diversity and biotechnological potentials of novel cold-adapted Acinetobacter strain - Hajra Kayani; Muhammad Asif Rasheed; Wadi B. Alonazi; Farrukh Jamil; Annam Hussain; ChangHui Yan; Raza Ahmed; Muhammad Ibrahim (Extremophiles, 2023)

Polyhydroxyalkanoate biosynthesis and optimisation of thermophilic Geobacillus stearothermophilus strain K4E3_SPR_NPP - Seema Prabhudev Rodge; Kundalik Shivaji Shende; Niranjan Prakashrao Patil (Extremophiles, 2023)

Improvement of duplex-specific nuclease salt tolerance by fusing DNA-binding domain of DNase from an extremely halotolerant bacterium Thioalkalivibrio sp. K90mix - Wenhao Hu; Jin Wang; Juan Li; Mengxia Yang; Zhixing Li; Xuning Zhang; Fang Wu; Yaqi Zhang; Zhidan Luo; Henghao Xu (Extremophiles, 2023)

Desulfatitalea alkaliphila sp. nov., an alkalipilic sulfate- and arsenate- reducing bacterium isolated from a terrestrial mud volcano - M. A. Khomyakova; A. Yu. Merkel; V. S. Segliuk; A. I. Slobodkin (Extremophiles, 2023)

Recombinant production, characterization and industrial application testing of a novel acidic exo/endo-chitinase from Rasamsonia emersonii - Kelly Dwyer; Ian S. Bentley; David A. Fitzpatrick; Aliabbas A. Saleh; Emma Tighe; Eibhilin McGleenan; Darragh Gaffney; Gary Walsh (Extremophiles, 2023)

Natrinema caseinilyticum sp. nov., Natrinema gelatinilyticum sp. nov., Natrinema marinum sp. nov., Natrinema zhouii sp. nov., extremely halophilic archaea isolated from marine environments and a salt mine - Yao Hu; Xue Ma; Xin-Xin Li; Shun Tan; Mu Cheng; Jing Hou; Heng-Lin Cui (Extremophiles, 2023)

Quantitative evaluation of endogenous reference genes for ddPCR under salt stress using a moderate halophile - Qinghua Xing; Noha M. Mesbah; Haisheng Wang; Jun Li; Baisuo Zhao (Extremophiles, 2023)

Halocatena marina sp. nov., a novel filamentous halophilic archaeon isolated from marine tidal flat and emended description of the genus Halocatena - Zhang-Ping Wu; Xi-Wen Zheng; Ya-Ping Sun; Bei-Bei Wang; Jing Hou; Heng-Lin Cui (Extremophiles, 2023)

Role of cell-substrate association during plant biomass solubilization by the extreme thermophile Caldicellulosiruptor bescii - Tunyaboon Laemthong; Ryan G. Bing; James R. Crosby; Mohamad J. H. Manesh; Michael W. W. Adams; Robert M. Kelly (Extremophiles, 2023)

Bacterial diversity of an acid mine drainage beside the Xichú River (Mexico) accessed by culture-dependent and culture-independent approaches - Elcia Margareth Souza Brito; Rémy Guyoneaud; César Augusto Caretta; Manon Joseph; Marisol Goñi-Urriza; Bernard Ollivier; Agnès Hirschler-Réa (Extremophiles, 2023)

Structural characterization and physicochemical properties of the exopolysaccharide produced by the moderately halophilic bacterium Chromohalobacter salexigens, strain 3EQS1 - Ibrahim M. Ibrahim; Yuliya P. Fedonenko; Elena N. Sigida; Maxim S. Kokoulin; Vyacheslav S. Grinev; Ivan G. Mokrushin; Gennady L. Burygin; Andrey M. Zakharevich; Alexander A. Shirokov; Svetlana A. Konnova (Extremophiles, 2023)

Post-dispersal astrobiological events: modelling macroevolutionary dynamics for lithopanspermia - Maico Stochero Fiedler; Milton de Souza Mendonça (Extremophiles, 2023)

Assessment of diversity of archaeal communities in Algerian chott - Imene Ikram Hassani; Inès Quadri; Archana Yadav; Sonia Bouchard; Didier Raoult; Hocine Hacène; Christelle Desnues (Extremophiles, 2023)

Biological role of the major AP (abasic site) endonuclease of an archaeon from geothermal environments - Rupal Jain; Dennis W. Grogan (Extremophiles, 2023)

A functionally uncharacterized type-2 malate/l-lactate dehydrogenase family protein from Thermus thermophilus HB8 catalyzes stereospecific reduction of 2-keto-3-deoxy-d-gluconate - Tetsu Shimizu; Akira Nakamura (Extremophiles, 2022)

Hyper-stimulation of Pyrococcus furiosus CRISPR DNA uptake by a self-transmissible plasmid - Elizabeth A. Watts; Sandra C. Garrett; Ryan J. Catchpole; Landon M. Clark; Brenton R. Graveley; Michael P. Terns (Extremophiles, 2022)

Rahnella sikkimica sp. nov., a novel cold-tolerant bacterium isolated from the glacier of Sikkim Himalaya with plant growth-promoting properties - Anil Kumar; Anne Le Flèche-Matéos; Rakshak Kumar; Fabienne Lomprez; Frédéric Fichenick; Dharam Singh; Patrick A. D. Grimont; Sanjay Kumar (Extremophiles, 2022)

Self-assembly of Aeropyrum pernix bacilliform virus 1 (APBV1) major capsid protein and its application as building blocks for nanomaterials - Yuka Sumikama; Atsushi Takashima; Tomohiro Mochizuki; Haruhiko Sakuraba; Toshihisa Ohshima; Shinji Sugihara; Shin-ichiro Suye; Takenori Satomura (Extremophiles, 2022)

Moorella sulfitireducens sp. nov., a thermophilic anaerobic bacterium isolated from a terrestrial thermal spring - Galina B. Slobodkina; A. Y. Merkel; A. A. Kuchierskaya; A. I. Slobodkin (Extremophiles, 2022)

Halorussus vallis sp. nov., Halorussus aquaticus sp. nov., Halorussus gelatinilyticus sp. nov., Halorussus limi sp. nov., Halorussus salilacus sp. nov., Halorussus salinisoli sp. nov.: six extremely halophilic archaea isolated from solar saltern, salt lake and saline soil - Xi-Wen Zheng; Zhang-Ping Wu; Ya-Ping Sun; Bei-Bei Wang; Jing Hou; Heng-Lin Cui (Extremophiles, 2022)

Electron transfer of extremophiles in bioelectrochemical systems - Miriam Edel; Laura-Alina Philipp; Jonas Lapp; Johannes Reiner; Johannes Gescher (Extremophiles, 2022)
The interaction of bacteria and archaea with electrodes is a relatively new research field which spans from fundamental to applied research and influences interdisciplinary research in the fields of microbiology, biochemistry, biotechnology as well as process engineering. Although a substantial understanding of electron transfer processes between microbes and anodes and between microbes and cathodes has been achieved in mesophilic organisms, the mechanisms used by microbes under extremophilic conditions are still in the early stages of discovery. Here, we review our current knowledge on the biochemical solutions that evolved for the interaction of extremophilic organisms with electrodes. To this end, the available knowledge on pure cultures of extremophilic microorganisms has been compiled and the study has been extended with the help of bioinformatic analyses on the potential distribution of different electron transfer mechanisms in extremophilic microorganisms.

Isotherm and kinetics modeling of biosorption and bioreduction of the Cr(VI) by Brachybacterium paraconglomeratum ER41 - Kaoutar Harboul; Imad Alouiz; Khalil Hammani; Abdenbi El-Karkouri (Extremophiles, 2022)

The catalytic and structural basis of archaeal glycerophospholipid biosynthesis - Niels A. W. de Kok; Arnold J. M. Driessen (Extremophiles, 2022)
Archaeal glycerophospholipids are the main constituents of the cytoplasmic membrane in the archaeal domain of life and fundamentally differ in chemical composition compared to bacterial phospholipids. They consist of isoprenyl chains ether-bonded to glycerol-1-phosphate. In contrast, bacterial glycerophospholipids are composed of fatty acyl chains ester-bonded to glycerol-3-phosphate. This largely domain-distinguishing feature has been termed the “lipid-divide”. The chemical composition of archaeal membranes contributes to the ability of archaea to survive and thrive in extreme environments. However, ether-bonded glycerophospholipids are not only limited to extremophiles and found also in mesophilic archaea. Resolving the structural basis of glycerophospholipid biosynthesis is a key objective to provide insights in the early evolution of membrane formation and to deepen our understanding of the molecular basis of extremophilicity. Many of the glycerophospholipid enzymes are either integral membrane proteins or membrane-associated, and hence are intrinsically difficult to study structurally. However, in recent years, the crystal structures of several key enzymes have been solved, while unresolved enzymatic steps in the archaeal glycerophospholipid biosynthetic pathway have been clarified providing further insights in the lipid-divide and the evolution of early life.

Role of carnitine in adaptation of Chromohalobacter salexigens DSM 3043 and its mutants to osmotic and temperature stress in defined medium - Xiang-Lin Meng; Xia Gao; Yuan-Ming Si; Li-Li Xu; Li-Zhong Guo; Wei-Dong Lu (Extremophiles, 2022)

Organic layer characteristics and microbial utilization of the biosulfur globules produced by haloalkaliphilic Thioalkalivibrio versutus D301 during biological desulfurization - Zhixia Liu; Maohua Yang; Tingzhen Mu; Jinlong Liu; Linxu Chen; Delu Miao; Jianmin Xing (Extremophiles, 2022)

Halorientalis salina sp. nov., Halorientalis marina sp. nov., Halorientalis litorea sp. nov.: three extremely halophilic archaea isolated from a salt lake and coarse sea salt - Bei-Bei Wang; Ya-Ping Sun; Zhang-Ping Wu; Xi-Wen Zheng; Jing Hou; Heng-Lin Cui (Extremophiles, 2022)

Genomic analysis of heavy metal-resistant Halobacterium salinarum isolated from Sfax solar saltern sediments - Houda Baati; Mariem Siala; Chafai Azri; Emna Ammar; Christopher Dunlap; Mohamed Trigui (Extremophiles, 2022)

Soil substrate culturing approaches recover diverse members of Actinomycetota from desert soils of Herring Island, East Antarctica - Nicole Benaud; Devan S. Chelliah; Sin Yin Wong; Belinda C. Ferrari (Extremophiles, 2022)
Antimicrobial resistance is an escalating health crisis requiring urgent action. Most antimicrobials are natural products (NPs) sourced from Actinomycetota , particularly the Streptomyces . Underexplored and extreme environments are predicted to harbour novel microorganisms with the capacity to synthesise unique metabolites. Herring Island is a barren and rocky cold desert in East Antarctica, remote from anthropogenic impact. We aimed to recover rare and cold-adapted NP-producing bacteria, by employing two culturing methods which mimic the natural environment: direct soil culturing and the soil substrate membrane system. First, we analysed 16S rRNA gene amplicon sequencing data from 18 Herring Island soils and selected the soil sample with the highest Actinomycetota relative abundance (78%) for culturing experiments. We isolated 166 strains across three phyla, including novel and rare strains, with 94% of strains belonging to the Actinomycetota . These strains encompassed thirty-five ‘species’ groups, 18 of which were composed of Streptomyces strains. We screened representative strains for genes which encode polyketide synthases and non-ribosomal peptide synthetases, indicating that 69% have the capacity to synthesise polyketide and non-ribosomal peptide NPs. Fourteen Streptomyces strains displayed antimicrobial activity against selected bacterial and yeast pathogens using an in situ assay. Our results confirm that the cold-adapted bacteria of the harsh East Antarctic deserts are worthy targets in the search for bioactive compounds.

Incomplete denitrification phenotypes in diverse Thermus species from diverse geothermal spring sediments and adjacent soils in southwest China - Chrisabelle C. Mefferd; Enmin Zhou; Cale O. Seymour; Noel A. Bernardo; Shreya Srivastava; Amanda J. Bengtson; Jian-Yu Jiao; Hailiang Dong; Wen-Jun Li; Brian P. Hedlund (Extremophiles, 2022)
A few members of the bacterial genus Thermus have been shown to be incomplete denitrifiers, terminating with nitrite (NO 2 − ) or nitrous oxide (N 2 O). However, the denitrification abilities of the genus as a whole remain poorly characterized. Here, we describe diverse denitrification phenotypes and genotypes of a collection of 24 strains representing ten species, all isolated from a variety of geothermal systems in China. Confirmed terminal products of nitrate reduction were nitrite or N 2 O, while nitric oxide (NO) was inferred as the terminal product in some strains. Most strains produced N 2 O; complete denitrification was not observed. Denitrification phenotypes were largely consistent with the presence of denitrification genes, and strains of the same species often had the same denitrification phenotypes and largely syntenous denitrification gene clusters. Genes for nirS and nirK coexisted in three Thermus brockianus and three Thermus oshimai genomes, which is a unique hallmark of some denitrifying Thermus strains and may be ecologically important. These results show that incomplete denitrification phenotypes are prominent, but variable, within and between Thermus species. The incomplete denitrification phenotypes described here suggest Thermus species may play important roles in consortial denitrification in high-temperature terrestrial biotopes where sufficient supply of oxidized inorganic nitrogen exists.

Strategies for anti-oxidative stress and anti-acid stress in bioleaching of LiCoO2 using an acidophilic microbial consortium - Dehong Liu; Hongjie Shi; Guanglin Chen; Xu Zhang; Tingyue Gu; Minglong Zhu; Wensong Tan (Extremophiles, 2022)

Asgard archaea in saline environments - Horia L. Banciu; Ionuț M. Gridan; Adrian V. Zety; Andreea Baricz (Extremophiles, 2022)

Halomonas faecis sp. nov., a halophilic bacterium isolated from human faeces - Zhu-Xiang Liu; Jin-Hua Chen; Ling-Ling Yang; Yu-Zhou Feng; Li-Ying Deng; Jian-Wu He; Shu-Kun Tang; Yi-Guang Chen (Extremophiles, 2022)

Evansella halocellulosilytica sp. nov., an alkali-halotolerant and cellulose-dissolving bacterium isolated from bauxite residue - Guo-Hong Liu; Manik Prabhu Narsing Rao; Qian-Qian Chen; Jian-Mei Che; Huai Shi; Bo Liu; Wen-Jun Li (Extremophiles, 2022)

Bacterial diversity and community structure in the rhizosphere of the halophyte Halocnemum strobilaceum in an Algerian arid saline soil - Sabrina Behairi; Nassima Baha; Mohamed Barakat; Philippe Ortet; Wafa Achouak; Thierry Heulin; Yahia Kaci (Extremophiles, 2022)

Simple sequence repeat insertion induced stability and potential ‘gain of function’ in the proteins of extremophilic bacteria - Sahil Mahfooz; Gauri Shankar; Jitendra Narayan; Pallavi Singh; Yusuf Akhter (Extremophiles, 2022)

Fungal diversity in a sediment core from climate change impacted Boeckella Lake, Hope Bay, north-eastern Antarctic Peninsula assessed using metabarcoding - Luiz Henrique Rosa; Mayara Baptistucci Ogaki; Juan Manuel Lirio; Rosemary Vieira; Silvia H. Coria; Otávio Henrique Bezerra Pinto; Micheline Carvalho-Silva; Peter Convey; Carlos Augusto Rosa; Paulo Eduardo Aguiar Saraiva Câmara (Extremophiles, 2022)

Limits to the three domains of life: lessons from community assembly along an Antarctic salinity gradient - Xiaoben Jiang; David J. Van Horn; Jordan G. Okie; Heather N. Buelow; Egbert Schwartz; Daniel R. Colman; Kelli L. Feeser; Cristina D. Takacs-Vesbach (Extremophiles, 2022)

Study of osmoadaptation mechanisms of halophilic Halomonas alkaliphila XH26 under salt stress by transcriptome and ectoine analysis - Tiantian Zhang; Xin Zhang; Yongzhen Li; Ning Yang; Lijuan Qiao; Zengqiang Miao; Jiangwa Xing; Derui Zhu (Extremophiles, 2022)

Desulfovulcanus ferrireducens gen. nov., sp. nov., a thermophilic autotrophic iron and sulfate-reducing bacterium from subseafloor basalt that grows on akaganéite and lepidocrocite minerals - Srishti Kashyap; Masroque Musa; Kaylee A. Neat; Deborah A. Leopo; James F. Holden (Extremophiles, 2022)
A deep-sea thermophilic bacterium, strain Ax17 T , was isolated from 25 °C hydrothermal fluid at Axial Seamount. It was obligately anaerobic and autotrophic, oxidized molecular hydrogen and formate, and reduced synthetic nanophase Fe(III) (oxyhydr)oxide minerals, sulfate, sulfite, thiosulfate, and elemental sulfur for growth. It produced up to 20 mM Fe 2+ when grown on ferrihydrite but < 5 mM Fe 2+ when grown on akaganéite, lepidocrocite, hematite, and goethite. It was a straight to curved rod that grew at temperatures ranging from 35 to 70 °C (optimum 65 °C) and a minimum doubling time of 7.1 h, in the presence of 1.5–6% NaCl (optimum 3%) and pH 5–9 (optimum 8.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain was 90–92% identical to other genera of the family Desulfonauticaceae in the phylum Pseudomonadota . The genome of Ax17 T was sequenced, which yielded 2,585,834 bp and contained 2407 protein-coding sequences. Based on overall genome relatedness index analyses and its unique phenotypic characteristics, strain Ax17 T is suggested to represent a novel genus and species, for which the name Desulfovulcanus ferrireducens is proposed. The type strain is Ax17 T (= DSM 111878 T = ATCC TSD-233 T ).

Anion-type modulates the effect of salt stress on saline lake bacteria - Bianka Csitári; Anna Bedics; Tamás Felföldi; Emil Boros; Hajnalka Nagy; István Máthé; Anna J. Székely (Extremophiles, 2022)
Beside sodium chloride, inland saline aquatic systems often contain other anions than chloride such as hydrogen carbonate and sulfate. Our understanding of the biological effects of salt composition diversity is limited; therefore, the aim of this study was to examine the effect of different anions on the growth of halophilic bacteria. Accordingly, the salt composition and concentration preference of 172 strains isolated from saline and soda lakes that differed in ionic composition was tested using media containing either carbonate, chloride or sulfate as anion in concentration values ranging from 0 to 0.40 mol/L. Differences in salt-type preference among bacterial strains were observed in relationship to the salt composition of the natural habitat they were isolated from indicating specific salt-type adaptation. Sodium carbonate represented the strongest selective force, while majority of strains was well-adapted to growth even at high concentrations of sodium sulfate. Salt preference was to some extent associated with taxonomy, although variations even within the same bacterial species were also identified. Our results suggest that the extent of the effect of dissolved salts in saline lakes is not limited to their concentration but the type of anion also substantially impacts the growth and survival of individual microorganisms.

tRNA modification profiles in obligate and moderate thermophilic bacilli - Hovik Panosyan; Franziska R. Traube; Caterina Brandmayr; Mirko Wagner; Thomas Carell (Extremophiles, 2022)
Transfer RNAs (tRNAs) are the most ancient RNA molecules in the cell, modification pattern of which is linked to phylogeny. The aim of this study was to determine the tRNA modification profiles of obligate ( Anoxybacillus, Geobacillus, Paragebacillus ) and moderate ( Bacillus, Brevibacillus, Ureibacillus , Paenibacillus ) thermophilic aerobic bacilli strains to find out its linkage to phylogenetic variations between species. LC-MS was applied for the quantification of modified nucleosides using both natural and isotopically labeled standards. The presence of m 2 A and m 7 G modifications at high levels was determined in all species. Relatively high level of i 6 A and m 5 C modification was observed for Paenibacillus and Ureibacillus , respectively. The lowest level of Cm modification was found in Bacillus. The modification ms 2 i 6 A and m 1 G were absent in Brevibacillus and Ureibacillus, respectively, while modifications Am and m 2 2 G were observed only for Ureibacillus . While both obligate and moderate thermophilic species contain Gm, m 1 G and ms 2 i 6 A modifications, large quantities of them (especially Gm and ms 2 i 6 A modification) were detected in obligate thermophilic ones ( Geobacillus, Paragebacillus and Anoxybacillus ). The collective set of modified tRNA bases is genus-specific and linked to the phylogeny of bacilli. In addition, the dataset could be applied to distinguish obligate thermophilic bacilli from moderate ones.

Microorganisms harbor keys to a circular bioeconomy making them useful tools in fighting plastic pollution and rising CO2 levels - Garabed Antranikian; Wolfgang R. Streit (Extremophiles, 2022)
The major global and man-made challenges of our time are the fossil fuel-driven climate change a global plastic pollution and rapidly emerging plant, human and animal infections. To meet the necessary global changes, a dramatic transformation must take place in science and society. This transformation will involve very intense and forward oriented industrial and basic research strongly focusing on (bio)technology and industrial bioprocesses developments towards engineering a zero-carbon sustainable bioeconomy. Within this transition microorganisms—and especially extremophiles—will play a significant and global role as technology drivers. They harbor the keys and blueprints to a sustainable biotechnology in their genomes. Within this article, we outline urgent and important areas of microbial research and technology advancements and that will ultimately make major contributions during the transition from a linear towards a circular bioeconomy.

Biome-specific distribution of Ni-containing carbon monoxide dehydrogenases - Masao Inoue; Kimiho Omae; Issei Nakamoto; Ryoma Kamikawa; Takashi Yoshida; Yoshihiko Sako (Extremophiles, 2022)
Ni-containing carbon monoxide dehydrogenase (Ni-CODH) plays an important role in the CO/CO 2 -based carbon and energy metabolism of microbiomes. Ni-CODH is classified into distinct phylogenetic clades, A–G, with possibly distinct cellular roles. However, the types of Ni-CODH clade used by organisms in different microbiomes are unknown. Here, we conducted a metagenomic survey of a protein database to determine the relationship between the phylogeny and biome distribution of Ni-CODHs. Clustering and phylogenetic analyses showed that the metagenome assembly-derived Ni-CODH sequences were distributed in ~ 60% Ni-CODH clusters and in all Ni-CODH clades. We also identified a novel Ni-CODH clade, clade H. Biome mapping on the Ni-CODH phylogenetic tree revealed that Ni-CODHs of almost all the clades were found in natural aquatic environmental and engineered samples, whereas those of specific subclades were found only in host-associated samples. These results are comparable with our finding that the diversity in the phylum-level taxonomy of host-associated Ni-CODH owners is statistically different from those of the other biomes. Our findings suggest that while Ni-CODH is a ubiquitous enzyme produced across diverse microbiomes, its distribution in each clade is biased and mainly affected by the distinct composition of microbiomes.

Prokaryotic diversity across a pH gradient in the “El Chichón” crater-lake: a naturally thermo-acidic environment - Irving Oswaldo Velázquez-Ríos; Reiner Rincón-Rosales; Federico Antonio Gutiérrez-Miceli; Rocio J. Alcántara-Hernández; Víctor Manuel Ruíz-Valdiviezo (Extremophiles, 2022)

The smallest space miners: principles of space biomining - Rosa Santomartino; Luis Zea; Charles S. Cockell (Extremophiles, 2022)
As we aim to expand human presence in space, we need to find viable approaches to achieve independence from terrestrial resources. Space biomining of the Moon, Mars and asteroids has been indicated as one of the promising approaches to achieve in-situ resource utilization by the main space agencies. Structural and expensive metals, essential mineral nutrients, water, oxygen and volatiles could be potentially extracted from extraterrestrial regolith and rocks using microbial-based biotechnologies. The use of bioleaching microorganisms could also be applied to space bioremediation, recycling of waste and to reinforce regenerative life support systems. However, the science around space biomining is still young. Relevant differences between terrestrial and extraterrestrial conditions exist, including the rock types and ores available for mining, and a direct application of established terrestrial biomining techniques may not be a possibility. It is, therefore, necessary to invest in terrestrial and space-based research of specific methods for space applications to learn the effects of space conditions on biomining and bioremediation, expand our knowledge on organotrophic and community-based bioleaching mechanisms, as well as on anaerobic biomining, and investigate the use of synthetic biology to overcome limitations posed by the space environments.

Haloprofundus salilacus sp. nov., Haloprofundus halobius sp. nov. and Haloprofundus salinisoli sp. nov.: three extremely halophilic archaea isolated from salt lake and saline soil - Si-Ya Li; Yu-Jie Xin; Chen-Xi Bao; Jing Hou; Heng-Lin Cui (Extremophiles, 2022)

Extremophile enzyme optimization for low temperature and high salinity are fundamentally incompatible - Luke Piszkin; Jeff Bowman (Extremophiles, 2022)

The monofunctional CO dehydrogenase CooS is essential for growth of Thermoanaerobacter kivui on carbon monoxide - Surbhi Jain; Alexander Katsyv; Mirko Basen; Volker Müller (Extremophiles, 2022)
Thermoanaerobacter kivui is a thermophilic acetogen that can grow on carbon monoxide as sole carbon and energy source. To identify the gene(s) involved in CO oxidation, the genome sequence was analyzed. Two genes potentially encoding CO dehydrogenases were identified. One, cooS , potentially encodes a monofunctional CO dehydrogenase, whereas another, acsA , potentially encodes the CODH component of the CODH/ACS complex. Both genes were cloned, a His-tag encoding sequence was added, and the proteins were produced from a plasmid in T. kivui . His-AcsA copurified by affinity chromatography with AcsB, the acetyl-CoA synthase of the CO dehydrogenase/acetyl CoA synthase complex. His-CooS copurified with CooF 1 , a small iron-sulfur center containing protein likely involved in electron transport. Both protein complexes had CO:ferredoxin oxidoreductase as well as CO:methyl viologen oxidoreductase activity, but the activity of CooSF 1 was 15-times and 231-times lower, respectively. To underline the importance of CooS, the gene was deleted in the CO-adapted strain. Interestingly, the ∆ cooS deletion mutant did not grow on CO anymore. These experiments clearly demonstrated that CooS is essential for growth of T. kivui on CO. This is in line with the hypothesis that CooS is the CO-oxidizing enzyme in cells growing on CO.

Metagenomic insights into Himalayan glacial and kettle lake sediments revealed microbial community structure, function, and stress adaptation strategies - Vijay Kumar; Subhash Kumar; Dharam Singh (Extremophiles, 2022)

Experimental study of proteome halophilicity using nanoDSF: a proof of concept - Lorenzo Carré; Éric Girard; Bruno Franzetti (Extremophiles, 2022)

Prokaryotic communities in the historic silver mine Reiche Zeche - Götz Haferburg; Tobias Krichler; Sabrina Hedrich (Extremophiles, 2022)
The research and education mine “Reiche Zeche” in Freiberg (Saxony, Germany) represents one of the most famous mining facilities reminiscent to the century-long history of silver production in the Ore Mountains. The mine was set up at the end of the fourteenth century and became part of the “Bergakademie Freiberg” in 1919. Galena, pyrite, sphalerite, arsenopyrite, and chalcopyrite are the most common minerals found in the mine. As acid mine drainage is generated from the dissolution of sulfidic ores, the microbial habitats within the adits and galleries are characterized by low pH and high concentrations of metal(loid)s. The community composition was investigated at locations characterized by biofilm formation and iron-rich bottom pools. Amplicon libraries were sequenced on a MiSeq instrument. The taxonomic survey yielded an unexpected diversity of 25 bacterial phyla including ten genera of iron-oxidizing taxa. The community composition in the snottites and biofilms only slightly differed from the communities found in acidic bottom pools regarding the diversity of iron oxidizers, the key players in most investigated habitats. Sequences of the Candidate Phyla Radiation as, e.g., Dojkabacteria and Eremiobacterota were found in almost all samples. Archaea of the classes Thermoplasmata and Nitrososphaeria were detected in some biofilm communities.

Correction to: Pentose degradation in archaea: Halorhabdus species degrade D-xylose, L-arabinose and D-ribose via bacterial-type pathways - Jan-Moritz Sutter; Ulrike Johnsen; Andreas Reinhardt; Peter Schönheit (Extremophiles, 2021)

Electron carriers involved in autotrophic and heterotrophic acetogenesis in the thermophilic bacterium Thermoanaerobacter kivui - Alexander Katsyv; Surbhi Jain; Mirko Basen; Volker Müller (Extremophiles, 2021)
Thermoanaerobacter kivui is an acetogenic model organism that reduces CO 2 with electrons derived from H 2 or CO, or from organic substrates in the Wood–Ljugdahl pathway (WLP). For the calculation of ATP yields, it is necessary to know the electron carriers involved in coupling of the oxidative and reductive parts of metabolism. Analyses of key catabolic oxidoreductases in cell-free extract (CFE) or with purified enzymes revealed the physiological electron carriers involved. The glyceraldehyde-3-phosphate dehydrogenase (GA3P-DH) assayed in CFE was NAD + -specific, NADP + was used with less than 4% and ferredoxin (Fd) was not used. The methylene-THF dehydrogenase was NADP + -specific, NAD + or Fd were not used. A Nfn-type transhydrogenase that catalyzes reduced Fd-dependent reduction of NADP + with NADH as electron donor was also identified in CFE. The electron carriers used by the potential electron-bifurcating hydrogenase (HydABC) could not be unambiguously determined in CFE for technical reasons. Therefore, the enzyme was produced homologously in T. kivui and purified by affinity chromatography. HydABC contained 33.9 ± 4.5 mol Fe/mol of protein and FMN; it reduced NADP + but not NAD + . The methylene-THF reductase (MetFV) was also produced homologously in T. kivui and purified by affinity chromatography. MetFV contained 7.2 ± 0.4 mol Fe/mol of protein and FMN; the complex did neither use NADPH nor NADH as reductant but only reduced Fd. In sum, these analysis allowed us to propose a scheme for entire electron flow and bioenergetics in T. kivui .

Fairy ring disease affects epiphytic algal assemblages associated with the moss Sanionia uncinata (Hedw.) Loeske (Bryophyta) on King George Island, Antarctica - Paulo E. A. S. Câmara; Pedro V. Eisenlohr; Lívia C. Coelho; Micheline Carvalho-Silva; Eduardo T. Amorim; Peter Convey; Otavio H. B. Pinto; Luiz Henrique Rosa (Extremophiles, 2021)

Antarctica as a reservoir of planetary analogue environments - Alessia Cassaro; Claudia Pacelli; Lorenzo Aureli; Ilaria Catanzaro; Patrick Leo; Silvano Onofri (Extremophiles, 2021)

Growth and photosynthesis acclimated response of the cyanobacterium Fischerella sp. FS 18 exposed to extreme conditions: alkaline pH, limited irradiance, and carbon dioxide concentration - Shadman Shokravi; Nadia Bahavar (Extremophiles, 2021)

Natural transformation in Gram-negative bacteria thriving in extreme environments: from genes and genomes to proteins, structures and regulation - Beate Averhoff; Lennart Kirchner; Katharina Pfefferle; Deniz Yaman (Extremophiles, 2021)
Extremophilic prokaryotes live under harsh environmental conditions which require far-reaching cellular adaptations. The acquisition of novel genetic information via natural transformation plays an important role in bacterial adaptation. This mode of DNA transfer permits the transfer of genetic information between microorganisms of distant evolutionary lineages and even between members of different domains. This phenomenon, known as horizontal gene transfer (HGT), significantly contributes to genome plasticity over evolutionary history and is a driving force for the spread of fitness-enhancing functions including virulence genes and antibiotic resistances. In particular, HGT has played an important role for adaptation of bacteria to extreme environments. Here, we present a survey of the natural transformation systems in bacteria that live under extreme conditions: the thermophile Thermus thermophilus and two desiccation-resistant members of the genus Acinetobacter such as Acinetobacter baylyi and Acinetobacter baumannii . The latter is an opportunistic pathogen and has become a world-wide threat in health-care institutions. We highlight conserved and unique features of the DNA transporter in Thermus and Acinetobacter and present tentative models of both systems. The structure and function of both DNA transporter are described and the mechanism of DNA uptake is discussed.

Halegenticoccus tardaugens sp. nov., an extremely halophilic archaeon isolated from a saline soil - Bing-Bing Liu; Nimaichand Salam; Shuang Cheng; Wen-qing Zhang; Yong-qing Zhou; Shu-xian Guo; Wen-Jun Li (Extremophiles, 2021)

Energy conservation under extreme energy limitation: the role of cytochromes and quinones in acetogenic bacteria - Florian P. Rosenbaum; Volker Müller (Extremophiles, 2021)
Acetogenic bacteria are a polyphyletic group of organisms that fix carbon dioxide under anaerobic, non-phototrophic conditions by reduction of two mol of CO 2 to acetyl-CoA via the Wood–Ljungdahl pathway. This pathway also allows for lithotrophic growth with H 2 as electron donor and this pathway is considered to be one of the oldest, if not the oldest metabolic pathway on Earth for CO 2 reduction, since it is coupled to the synthesis of ATP. How ATP is synthesized has been an enigma for decades, but in the last decade two ferredoxin-dependent respiratory chains were discovered. Those respiratory chains comprise of a cytochrome-free, ferredoxin-dependent respiratory enzyme complex, which is either the Rnf or Ech complex. However, it was discovered already 50 years ago that some acetogens contain cytochromes and quinones, but their role had only a shadowy existence. Here, we review the literature on the characterization of cytochromes and quinones in acetogens and present a hypothesis that they may function in electron transport chains in addition to Rnf and Ech.

Ecological succession of fungal and bacterial communities in Antarctic mosses affected by a fairy ring disease - Luiz Henrique Rosa; Lívia da Costa Coelho; Otávio Henrique Bezerra Pinto; Micheline Carvalho-Silva; Peter Convey; Carlos Augusto Rosa; Paulo E. A. S. Câmara (Extremophiles, 2021)

Transcriptomic responses of haloalkalitolerant bacterium Egicoccus halophilus EGI 80432T to highly alkaline stress - Dai-Di Chen; Manzoor Ahmad; Yong-Hong Liu; Shuang Wang; Bing-Bing Liu; Shu-Xian Guo; Hong-Chen Jiang; Wen-Sheng Shu; Wen-Jun Li (Extremophiles, 2021)