Acetogenesis and acetotrophy in a hexanoate‐catabolizing microbial association isolated from anoxic landfill

Metabolism of the key intermediates, acetate and hydrogen, in anaerobic hexanoate catabolism by an interacting microbial association isolated from a landfill was examined in the presence of sulphate. Hydrogen (the β‐oxidation product of hexanoate and butyrate), was competitively utilized by the component sulphate‐reducing bacteria whereas in the absence of sulphate an interaction between H 2 ‐utilizing acetogenic and methanogenic bacteria facilitated H 2 removal, with acetate catabolism restricted to methanogenic bacteria. A possible mechanism for energy conservation was suggested in which excess electrons were stored as acetate for subsequent usage as an energy source.