Open AccessEnzyme activities in and energetics of acetate metabolism by the mesophilic syntrophically acetate‐oxidizing anaerobe Clostridium ultunense
Author(s) -
Schnürer Anna,
Svensson Bo H,
Schink Bernhard
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb12664.x
Subject(s) - carbon monoxide dehydrogenase , chemistry , enzyme , acetate kinase , biochemistry , oxidizing agent , clostridium , metabolism , mesophile , dehydrogenase , methylene , organic chemistry , biology , bacteria , escherichia coli , carbon monoxide , catalysis , genetics , gene
The metabolism of the syntrophically acetate‐oxidizing Clostridium ultunense was investigated with cell extracts of the pure culture and the methanogenic triculture from which C. ultunense was isolated. Enzyme measurements indicated that: (1) the CO dehydrogenase (Wood) pathway was used both during acetate formation and during acetate oxidation; (2) methylene‐tetrahydrofolate reductase activity was not detected during acetate oxidation; (3) two different methylene‐tetrahydrofolate dehydrogenase enzymes were active, depending on the direction in which the Wood pathway was used. The hydrogen partial pressure in the headspace of a growing triculture varied between 1.6 and 6.8 Pa, indicating that C. ultunense and the methanogenic partner each get about −17 kJ per mol reaction in this syntrophic cooperation, thus operating at the lowermost range of energy to be exploited by a living organism.