Biodegradation of diethyl phthalate in soil by a novel pathway

Biodegradation of diethyl phthalate (DEP) has been shown to occur as a seri es of sequential steps common to the degradation of all phthalates. Primary degradation of DEP to phthalic acid (PA) has been reported to involve the hydrolysis of each of the two diethyl chains of the phthalate to produce th e monoester monoethyl phthalate (MEP) and then PA. However, in soil co-cont aminated with DEP and MeOH, biodegradation of the phthalate to PA resulted in the formation of three compounds, in addition to MEP. These were charact erised by gas chromatography-electron ionisation mass spectrometry and nucl ear magnetic resonance as ethyl methyl phthalate, dimethyl phthalate and mo nomethyl phthalate, and indicated the existence of an alternative pathway f or the degradation of DEP in Soil co-contaminated with MeOH. Transesterific ation or demethylation were proposed as the mechanisms for the formation of the three compounds, although the 7:1 ratio of H2O to MeOH means that tran sesterification is unlikely. (C) 2000 Federation of European Microbiologica l Societies. Published by Elsevier Science B.V. All rights reserved.