Detection of Diazotrophy in the Acetylene-Fermenting Anaerobe Pelobacter sp. Strain SFB93.

摘要: Acetylene (C2H2) is a trace constituent of the present Earth's oxidizing atmosphere, reflecting mixture terrestrial and marine emissions from anthropogenic, biomass-burning, unidentified biogenic sources. Fermentation acetylene was serendipitously discovered during C2H2 block assays N2O reductase, Pelobacter acetylenicus shown to grow on via hydratase (AH). AH W-containing, catabolic, low-redox-potential enzyme that, unlike nitrogenase (N2ase), specific for acetylene. fermentation rare metabolic process that well characterized only in P. DSM3246 DSM3247 sp. strain SFB93. To better understand genetic controls activity, we sequenced genomes three acetylene-fermenting strains. Genome assembly annotation produced novel containing gene sequences AH, with two copies being In addition, all five compulsory genes iron-molybdenum N2ase were also genomes, indicating cooccurrence transformation pathways. Nitrogen fixation growth showed DSM3426 could ferment absence ammonium, but no ethylene produced. However, SFB93 degraded and, ethylene, an active N2ase. Diazotrophic observed under N2 not experimental incubated argon. exhibits nitrogen fixation, known biochemical mechanisms transformation. Our results indicate complex interactions between suggest evolutionary pathways these relic enzymes early Earth modern days.IMPORTANCE Here show single can carry out using transform These findings provide new insights into transformations adaptations nutrient (C N) energy acquisition by microorganisms. Enhanced understanding (i.e., extent, occurrence, rates) environments important use as potential biomarker extraterrestrial life degradation anthropogenic contaminants.