Two-stage anaerobic digestion and trace metals (TM) supplementation are promising techniques to improve biogas production. Fe 2+ and Ni 2+ can improve process stability since they are part of the cofactors of enzymes and microorganisms’ growth. This work attempted to evaluate the effect of Fe 2+ and Ni 2+ addition on H 2 -rich biogas production from organic solid waste and the CH 4 -rich biogas production from the acidogenic e...

Summary The saprophyte Pseudomonas aeruginosa is a versatile opportunistic pathogen causing infections in immunocompromised individuals. To facilitate its adaptation to a large variety of niches, this bacterium exploits population density‐dependent gene regulation systems called quorum sensing (QS). In P. aeruginosa , three distinct but interrelated QS systems ( las , rhl and pqs ) regulate the production of many survival and...

Summary High‐affinity hydrogen ( H 2 )‐oxidizing bacteria possessing group 5 [ NiFe ]‐hydrogenase genes are important contributors to atmospheric H 2 uptake in soil environments. Although previous studies reported the occurrence of a significant H 2 uptake activity in vegetation, there has been no report on the identification and diversity of the responsible microorganisms. Here, we show the existence of plant‐associated bacte...

Summary Uptake of molecular hydrogen (H 2 ) by soil is a biological reaction responsible for ∼80% of the global loss of atmospheric H 2 . Indirect evidence obtained over the last decades suggests that free soil hydrogenases with an unusually high affinity for H 2 are carrying out the reaction. This assumption has recently been challenged by the isolation of Streptomyces sp. PCB7, displaying the high‐affinity H 2 uptake activit...