Autotrophic carbon dioxide fixation via the Calvin-Benson-Bassham cycle by the denitrifying methanotroph "Candidatus Methylomirabilis oxyfera".

摘要: ABSTRACT Methane is an important greenhouse gas and the most abundant hydrocarbon in Earth9s atmosphere. Methanotrophic microorganisms can use methane as their sole energy source play a crucial role mitigation of emissions environment. “Candidatus Methylomirabilis oxyfera” recently described intra-aerobic methanotroph that assumed to nitric oxide generate internal oxygen oxidize via conventional aerobic pathway, including monooxygenase reaction. Previous genome analysis has suggested that, like verrucomicrobial methanotrophs, “Ca. encodes transcribes genes for Calvin-Benson-Bassham (CBB) cycle carbon assimilation. Here we provide multiple independent lines evidence autotrophic dioxide fixation by CBB cycle. The activity ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), key enzyme cycle, cell extracts from enrichment culture was shown account up 10% total oxidation activity. Labeling studies with whole cells batch incubations supplied either 13CH4 or [13C]bicarbonate revealed biomass lipids became significantly more enriched 13C after incubation 13C-labeled bicarbonate (and unlabeled methane) than bicarbonate), providing fixation. Besides this experimental approach, detailed genomic transcriptomic demonstrated operational oxyfera.” Altogether, these results show active plays major assimilation bacteria. Our suggest autotrophy might be widespread among methanotrophs previously implies methanotrophic community environment not necessarily 13C-depleted lipids.