Pathways for the degradation of MTBE and other fuel oxygenates by isolate PM1

To help characterize the pathways of MTBE degradation by PM1 (a strain of bacteria isolated from a compost biofilter at the Los Angeles County Joint Water Pollution Control Plant in Carson, CA), direct aqueous injection (DAI) GC/MS was used to determine the degradation products of MTBE, TAME, ETBE, di-isopropyl ether (DIPE), tert-amyl alcohol (TAA), and tert-butyl alcohol (TBA). The DAI technique allowed simultaneous quantification of reactants and products and monitoring of the reaction over a wide range of concentrations. TBA was an intermediate in the degradation pathways for MTBE and ETBE, and TAA was an intermediate in the degradation pathway for TAME. PM1 rapidly mineralized MTBE under favorable conditions (aerobic conditions and in the absence of more favorable substrates). The rates of degradation of TAME, ETBE, TBA by PM1 were of the same order of magnitude as the degradation rate for MTBE.