Research Product

Aquifer remediation has been conducted for three years by a purge and treat system utilizing granular activated carbon (GAC) filtration of the groundwater at a gas production facility contaminated with aromatic petroleum hydrocarbons: benzene, toluene, ethylbenzene, and xylenes (BTEX). Analyses have been made of groundwater and GAC particles for presence and metabolic diversity of microorganisms capable of degrading BTEX under aerobic and denitrifying conditions. Seven bacterial isolates were selected for detailed investigation. Determination of growth substrate profiles and also oxygen consumption profiles for toluene-induced cells indicated that catabolic diversity was significantly broader than the induction specificity used by the microorganisms for degradation of aromatic hydrocarbons. Pseudomonas pickettii PKO1 was selected as a model organism for genetic analysis of BTEX catabolism by such microorganisms. A 27 kilobase BamHI restriction endonuclease DNA fragment cloned from strain PKO1 and expressed in P. aeruginosa PAO1 allowed the latter strain to utilize benzene, toluene, phenol, and m-cresol under aerobic conditions and toluene and ethylbenzene under anaerobic, denitrifying conditions.