Microbial degradation of benzene, toluene, ethylbenzene and xylene isomers(BTEX) contaminated groundwater in Korea

A mixed culture derived from a gasoline-contaminated aquifer in Korea was e nriched on toluene at 25 degreesC. A study was conducted to characterize th e substrate interaction of BTEX by toluene-enriched consortia and determine the effects of initial BTEX concentration on BTEX degradation. Substrate d egradation patterns in individual aromatics were found to differ significan tly from patterns for aromatics in mixtures. In the experiment of a single substrate, toluene was degraded fastest, followed by benzene, ethylbenzene, and the xylenes. In BTEX mixtures, degradation followed the order of tolue ne, ethylbenzene, benzene, and the xylenes. The studies conducting with tol uene-enriched consortia evaluated substrate interactions by the concurrent presence of multiple BTEX compounds and revealed a range of substrate inter action patterns including no interaction, stimulation, inhibition, and come tabolism. The simultaneous presence of benzene and toluene were degraded wi th a slight inhibitory effect on each other. Ethylbenzene was shown to be t he most potent inhibitor of BTEX degradation. p-xylene also inhibited the d egradation of benzene, toluene, and ethylbenzene, whereas the presence of e ither benzene or toluene enhanced the degradation of ethylbenzene and the x ylenes.