Open AccessThermodynamics of hydrogen metabolism in methanogenic cocultures degrading ethanol or lactate
Author(s) -
Seitz H.J.,
Schink B.,
Conrad R.
Publication year - 1988
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.1574-6968.1988.tb13918.x
Subject(s) - hydrogen , ethanol , desulfovibrio vulgaris , gibbs free energy , chemistry , desulfovibrio , hydrogenase , biochemistry , metabolism , nuclear chemistry , thermodynamics , bacteria , biology , organic chemistry , physics , sulfate , genetics
Pure cultures of Desulfovibrio vulgaris or Pelobacter acetylenicus do not grow with lactate or ethanol, respectively, under obligately proton‐ reducing conditions. However, a small part of these substrates was oxidized and molecular hydrogen was produced up to 4.2 and 3.2 kPa, respectively. During growth in syntrophic methanogenic cocultures with Methanospirillum hungatei as partner, maximum hydrogen partial pressures were significantly lower (0.7 to 2.5 kPa) than in the corresponding pure cultures. Calculation of Gibbs free energies for the prevailing culture conditions showed that H 2 partial pressures were kept in a range at which both, H 2 ‐producing and H 2 ‐consuming reactions, were thermodynamically permissive in pure as well as in syntrophic mixed cultures.