Anaerobic Biodegradation of Monoaromatic Compounds

Toluic acids degradation was studied under§methanogenic and sulfate-reducing conditions. All§toluic acid isomers were degraded under§sulfate-reducing conditions, with m-toluate§degradation occurring at the fastest rate. Benzoate,§isophthalate, and m-carboxybenzylsuccinate were§detected in m-toluate-degrading enrichments,§suggesting a fumarate addition mechanism for§m-toluate degraation.§ The metabolism of benzoate by Syntrophus§aciditrophicus in coculture with hydrogen-using§microorganisms was studied. Cyclohexane carboxylate,§cyclohex-1-ene carboxylate, pimelate, and glutarate§transiently accumulated during growth with benzoate.§S. aciditrophicus also metabolized benzoate in pure§culture in the absence of hydrogen-utilizing partners§or terminal-electron acceptors. § A novel protocol was developed to determine§whether the degradation of toluene under§sulfate-reducing conditions depends on interspecies§hydrogen transfer. Although the outcome of the§experiments failed to support the tested hypothesis,§the protocol will be useful to determine the role of§interspecies hydrogen transfer in the degradation of§different compounds in environmental samples.