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Archaeoglobus fulgidus couples CO oxidation to sulfate reduction and acetogenesis with transient formate accumulation
Author(s) -
Henstra Anne M.,
Dijkema Cor,
Stams Alfons J. M.
Publication year - 2007
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2007.01306.x
Subject(s) - formate , thiosulfate , formate dehydrogenase , sulfate , sulfide , sulfur , chemistry , inorganic chemistry , acetogenesis , medicinal chemistry , biochemistry , nuclear chemistry , organic chemistry , catalysis , methane , anaerobic digestion
Summary The genome sequence of Archaeoglobus fulgidus VC16 encodes three CO dehydrogenase genes. Here we explore the capacity of A. fulgidus to use CO as growth substrate. Archaeoglobus fulgidus VC16 was successfully adapted to growth medium that contained sulfate and CO. In the presence of CO and sulfate the culture OD 660 increased to 0.41 and sulfide, carbon dioxide, acetate and formate were formed. Accumulation of formate was transient. Similar results, except that no sulfide was formed, were obtained when sulfate was omitted. Hydrogen was never detected. Under the conditions tested, the observed concentrations of acetate (18 mM) and formate (8.2 mM) were highest in cultures without sulfate. Proton NMR spectroscopy indicated that CO 2 , and not CO, is the precursor of formate and the methyl group of acetate. Methylviologen‐dependent formate dehydrogenase activity (1.4 μmol formate oxidized min −1 mg −1 ) was detected in cell‐free extracts and expected to have a role in formate reuptake. It is speculated that formate formation proceeds through hydrolysis of formyl‐methanofuran or formyl‐tetrahydromethanopterin. This study demonstrates that A. fulgidus can grow chemolithoautotrophically with CO as acetogen, and is not strictly dependent on the presence of sulfate, thiosulfate or other sulfur compounds as electron acceptor.