Towards elucidation of microbial community metabolic pathways: unravellingthe network of carbon sharing in a pollutant-degrading bacterial consortium by immunocapture and isotopic ratio mass spectrometry

Although much information on metabolic pathways within individual organisms is available, little is known about the pathways operating in natural comm unities in which extensive sharing of nutritional resources is the rule. In order to analyse such a consortium pathway, we have investigated the flow of 4-chlorosalicylate as carbon substrate within a simple chemostat microbi al community using C-13-labelled metabolites and isotopic ratio mass spectr ometric analysis of label enrichment in immunocaptured member populations o f the community. A complex pathway network of carbon sharing was thereby re vealed, involving two different metabolic routes, one of which is completel y novel and involves the toxic metabolite protoanemonin, The high stability of the community results, at least in part, from interdependencies based o n carbon sharing and the rapid removal of toxic metabolites.