Life on earth evolved in the absence of oxygen with inorganic gases as potential sources of carbon and energy. Among the alternative mechanisms for carbon dioxide (CO₂) fixation in the living world, only the reduction of CO₂ by the Wood-Ljungdahl pathway, which is used by acetogenic bacteria, complies with the two requirements to sustain life: conservation of energy and production of biomass. However, how energy is conserved in acetogenic bacteria has been an enigma since their discovery. In this Review, we discuss the latest progress on the biochemistry and genetics of the energy metabolism of model acetogens, elucidating how these bacteria couple CO₂ fixation to energy conservation.
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http://dx.doi.org/10.1038/nrmicro3365 | DOI Listing |
Biotechnol Bioeng
December 2024
Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark.
Acetogenic bacteria play an important role in various biotechnological processes, because of their chemolithoautotrophic metabolism converting carbon dioxide with molecular hydrogen (H) as electron donor into acetate. As the main factor limiting acetogenesis is often H, insights into the H consumption kinetics of acetogens are required to assess their potential in biotechnological processes. In this study, initial H consumption rates at a range of different initial H concentrations were measured for three different acetogens.
View Article and Find Full Text PDFFront Microbiol
December 2024
Institute of Microbiology, Leibniz University Hannover, Hannover, Germany.
Peatlands are invaluable but threatened ecosystems that store huge amounts of organic carbon globally and emit the greenhouse gasses carbon dioxide (CO) and methane (CH). Trophic interactions of microbial groups essential for methanogenesis are poorly understood in such systems, despite their importance. Thus, the present study aimed at unraveling trophic interactions between fermenters and methanogens in a nitrogen-limited, subarctic, pH-neutral fen.
View Article and Find Full Text PDFFEBS J
December 2024
Department of Functional and Evolutionary Ecology, University of Vienna, Austria.
Corrinoids are cobalt-containing tetrapyrroles. They include adenosylcobalamin (vitamin B) and cobamides that function as cofactors and coenzymes for methyl transfer, radical-dependent and redox reactions. Though cobamides are the most complex cofactors in nature, they are essential in the acetyl-CoA pathway, thought to be the most ancient CO-fixation pathway, where they perform a pterin-to-cobalt-to-nickel methyl transfer reaction catalyzed by the corrinoid iron-sulphur protein (CoFeS).
View Article and Find Full Text PDFmBio
December 2024
Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia.
Bioresour Technol
December 2024
Institute of Molecular Biology and Biotechnology of Prokaryotes, University of Ulm, Ulm, Germany. Electronic address:
Acetogens are a diverse group of anaerobic bacteria that are capable of carbon dioxide fixation and have for long fascinated scientists due to their unique metabolic prowess. Historically, acetogens have been recognized for their remarkable ability to grow and to produce acetate from different one-carbon sources, including carbon dioxide, carbon monoxide, formate, methanol, and methylated organic compounds. The key metabolic pathway in acetogens responsible for converting these one-carbon sources is ́the Wood-Ljungdahl pathway.
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