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Title: Growth of desulfovibrio in lactate or ethanol media low in sulfate in association with H/sub 2/-utilizing methanogenic bacteria

Journal Article · · Appl. Environ. Microbiol.; (United States)
OSTI ID:6631130

In the analysis of an ethanol-CO/sub 2/ enrichment of bacteria from an anaerobic sewage digestor, a strain tentatively identified as Desulfovibrio vulgaris and an H/sub 2/-utilizing methanogen resembling Methanobacterium formicicum were isolated, and they were shown to represent a synergistic association of two bacterial species similar to that previously found between S organism and Methanobacterium strain MOH isolated from Methanobacillus omelianskii. In low-sulfate media, the desulfovibrio produced acetate and H/sub 2/ from ethanol and acetate, H/sub 2/, and, presumably, CO/sub 2/ from lactate; but growth was slight and little of the energy source was catabolized unless the organism was combined with an H/sub 2/-utilizing methanogenic bacterium. The type strains of D. vulgaris and Desulfovibrio desulfuricans carried out the same type of synergistic growth with methanogens. In mixtures of desulfovibrio and strain MOH growing on ethanol, lactate, or pyruvate, diminution of methane produced was stoichiometric with the moles of sulfate added, and the desulfovibrios grew better with sulfate addition. The energetics of the synergistic associations and of the competition between the methanogenic system and sulfate-reducing system as sinks for electrons generated in the oxidation of organic materials such as ethanol, lactate, and acetate are discussed. It is suggested that lack of availability of H/sub 2/ for growth of methanogens is a major factor in suppression of methanogenesis by sulfate in natural ecosystems. The results with these known mixtures of bacteria suggest that hydrogenase-forming sulfate-reducing bacteria could be active in some methanogenic ecosystems that are low in sulfate.

Research Organization:
Univ. of Illinois, Urbana
OSTI ID:
6631130
Journal Information:
Appl. Environ. Microbiol.; (United States), Vol. 33:5
Country of Publication:
United States
Language:
English