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Multiâstage chemostat investigation of interspecies interactions in a hexanoateâcatabolizing microbial association isolated from anoxic landfill
- Coutts, D. A. P., Senior, E., Balba, M. T. M.
- Journal of applied microbiology 1987 v.62 no.3 pp. 251-260
- carbon dioxide, electrons, habitats, interspecific competition, landfills, metabolism, methane production, methanogens, models, oxidation
- Spatial separations of physicoâchemical environments (habitat domains) with maintenance of overlapping zones of influence (activity domains) with multiâstage chemostat models were used to facilitate examination of interspecies interactions within a hexanoateâcatabolizing microbial association isolated from anoxic landfill. Under a constant dilution rate regime, in the presence of 1.4 and 5 mmol/l influent sulphate, consolidation of the major metabolic events of hexanoate catabolism, sulphate reduction, acetogenesis and methanogenesis took place in the first vessel of a fiveâvessel array suggesting considerable overlap of activity domains or localization around the habitat domains. Evidence of partial competitive displacement was not apparent until 10 mmol/l of sulphate was used. Introduction of a nonâconstant dilution rate regime to a threeâvessel model, subjected to an influent sulphate concentration of 1.4 mmol/l, effected the displacement of the methanogenic species and, as a consequence, in the presence of sulphate limitation, CO2 reduction became the major sink for excess electrons generated from hexanoate oxidation. A hypothetical scheme of anaerobic hexanoate catabolism by the interacting microbial association was developed.