Aerobic biodegradation of benzene, toluene and ethylbenzene in liquid medium by a bacterial consortium, isolated from non-history clay soil, and their interrelation effect

The present study was carried out in order to investigate the ability of is olated subsurface bacteria, from a non-history clay soil, to biodegrade the non-aqueous phase-liquids (NAPLs), monoaromatic hydrocarbons: benzene, tol uene and ethylbenzene. First stage of the study was focussed on stand-alone biodegradation of each contaminant under described conditions. Benzene (10 0, 260 and 500 mg/l) exposed to isolated soil bacteria for 14 days, was bio degraded 100, 70 and 50%, respectively, ethylbenzene (100, 260 and 500 mg/l ) at 85, 87 and 90%, respectively and toluene (100, 260 and 500 mg/l) revea led the lowest rate of 45, 50 and 52%. Toluene and ethylbenzene showed a di rect increase in biodegradation associated with increase in their concentra tion. The second stage was the biodegradation of benzene, toluene and ethyl benzene admixture tall three compounds at the very same concentrations, wlv ) in glucose absence and supplemented with Tween 80 (10 and 15 mg/l). The o verall biodegradation improved when contaminants were mixed together.