Insertion sequences (IS) are drivers of bacterial diversification by facilitating recruitment and horizontal transfer of adaptive genes involving composite transposon structures, but their evolutionary role at the community level is rarely addressed. This study explores the dynamics of IS 1071 and the cargo of IS 1071 ‐associated putative composite transposons in the establishment of a pesticide‐degrading microbiome in an on‐f...

The negative diversity‐invasion relationship observed in microbial invasion studies is commonly explained by competition between the invader and resident populations. However, whether this relationship is affected by invader‐resident cooperative interactions is unknown. Using ecological and mathematical approaches, we examined the survival and functionality of Aminobacter niigataensis MSH1 to mineralize 2,6‐dichlorobenzamide (...

Summary IS 1071 , an insertion element that primarily flanks organic xenobiotic degradation genes in cultured isolates, is suggested to play a key role in the formation and distribution of bacterial catabolic pathway gene clusters. However, in environmental settings, the identity of the IS 1071 genetic cargo and its correspondence to the local selective conditions remain unknown. To respond, we developed a long‐range PCR appro...

Summary Variovorax sp. WDL1 mediates hydrolysis of the herbicide linuron into 3,4‐dichloroaniline (DCA) and N,O ‐dimethylhydroxylamine in a tripartite bacterial consortium with Comamonas testosteroni WDL7 and Hyphomicrobium sulfonivorans WDL6. Although strain WDL1 contains the dcaQTA1A2B operon for DCA oxidation, this conversion is mainly performed by WDL7. Phenotypic diversification observed in WDL1 cultures and scrutiny of t...

Summary Biostimulation is widely used to enhance reductive dechlorination of chlorinated ethenes in contaminated aquifers. However, the knowledge on corresponding biogeochemical responses is limited. In this study, glycerol was injected in an aquifer contaminated with cis ‐dichloroethene (cDCE), and geochemical and microbial shifts were followed for 265 days. Consistent with anoxic conditions and sulfate reduction after biosti...

Summary Carbofuran‐mineralizing strain Novosphingobium sp. KN65.2 produces the CfdJ enzyme that converts the N ‐methylcarbamate insecticide to carbofuran phenol. Purified CfdJ shows a remarkably low K M towards carbofuran. Together with the carbaryl hydrolase CehA of Rhizobium sp. strain AC100, CfdJ represents a new protein family with several uncharacterized bacterial members outside the proteobacteria. Although both enzymes...

Summary A series of long‐term Zn‐contaminated soils was sampled around a galvanized pylon. The potential nitrification rate (PNR) was unaffected by the soil total Zn concentrations up to 25 mmol Zn kg −1 whereas spiking the uncontaminated control soil with ZnCl 2 to identical total concentrations completely eliminated nitrification. The larger sensitivity of the PNR to spiked ZnCl 2 than to the Zn added in the field was equall...

Summary Mycobacterium is often isolated from polycyclic aromatic hydrocarbon (PAH)‐contaminated soil as degraders of PAHs. In model systems, Mycobacterium shows attachment to the PAH substrate source, which is considered to be a particular adaptation to low bioavailability as it results into increased substrate flux to the degraders. To examine whether PAH‐degrading Mycobacterium in real PAH‐contaminated soils, in analogy with...

Summary Sphingomonas is an organism of major interest for the degradation of organic contaminants in soils and other environments. A medium based on the aminoglycoside antibiotic streptomycin (Sm) was developed, which, together with the yellow pigmentation of Sphingomonas , facilitated the detection, recovery and quantification of culturable Sphingomonas from soils. All 29 previously described bacterial strains belonging to 17...

Summary Pseudomonas putida BN210, carrying the self‐ transferable clc ‐element encoding degradation of 3‐chlorobenzoate on the chromosome, was used as inoculum in different membrane biofilm reactors treating 3‐chlorobenzoate‐contaminated model wastewater. Analysis of the bacterial population in the effluent and in the biofilm showed the loss of BN210 beyond detection from the reactors and the appearance of several novel 3‐chlo...