Biodegradation of oxyethylated fatty alcohols by bacteria Microbacterium strain E19

Abstract

The Microbacterium sp. E19 (E19) has been isolated from soil contaminated with crude oil and is a candidate for surfactant enhanced remediation of hydrocarbon polluted soil. Oxyethylated alcohols (OA) are candidates for this process enhancement. The aim of this work was the investigation of biodegradation of a representative oxyethylated fatty alcohol (polydispersal surfactant C12E10(C12E10)) by E19 under static model conditions with the surfactant as a sole source of organic carbon. LC-MS was used for the identification of metabolites and determination of surfactant and metabolite concentrations. Apart from [M+NH4](+) ethoxylate 'fingerprints', [M+2NH4](++) 'fingerprints' (m/z=22) were used for the identification of particular species. Primary biodegradation of C12E10 by E19 is almost complete over 30 days of the test (97 percent). The major metabolites during the initial period of the test are homologs of oxyethylated alcohols ω-carboxylated in the oxyethylene chain and poly(ethylene glycols). 1/3 of the total C12Ex is metabolized along this pathway. Concentration of these metabolites is stable over the subsequent days of the test. Further biodegradation of C12Ex causes an enrichment of the residue with C12Ex homologs having a longer oxyethylene chain. However, intermediates of this process were not identified.