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Growth of the acetogenic bacterium Acetobacterium woodii by dismutation of acetaldehyde to acetate and ethanol
Author(s) -
Trifunović Dragan,
Berghaus Natalie,
Müller Volker
Publication year - 2020
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12811
Subject(s) - acetaldehyde , bacteria , chemistry , biochemistry , acetate kinase , metabolic pathway , alcohol dehydrogenase , enzyme , anaerobic bacteria , ethanol , carbon fixation , nad+ kinase , metabolism , bifunctional , biology , catalysis , escherichia coli , genetics , photosynthesis , gene
Summary Acetogenic bacteria are a group of strictly anaerobic bacteria that may have been first life forms on Earth since they employ an ancient pathway for CO 2 fixation into acetyl‐CoA that is coupled to the synthesis of ATP, the Wood–Ljungdahl pathway. Electrons for CO 2 reduction are derived from oxidation of H 2 or CO and thus, these bacteria can grow lithotrophically on gases present on early Earth. Among the organic molecules present on early Earth is acetaldehyde, a highly volatile C2 compound. Here, we demonstrate that the acetogenic model bacterium Acetobacterium woodii grows on acetaldehyde. Acetaldehyde is dismutated to ethanol and acetyl‐CoA, most likely by the bifunctional alcohol dehydrogenase AdhE. Acetyl‐CoA is converted to acetate by two subsequent enzymes, phosphotransacetylase and acetate kinase, accompanied by the synthesis of ATP by substrate‐level phosphorylation. Apparently, growth on acetaldehyde does not employ the Wood–Ljungdahl pathway. Our finding opens the possibility of a simple and ancient metabolic pathway with only three enzymes that allows for biomass (acetyl‐CoA) and ATP formation on early Earth.