Abstract: A bacterial strain (Q2), which could utilize quinoline as the sole sources of carbon, nitrogen and energy, was isolated from the soil contaminated by petroleum at the wastewater treating plant of a petrochemical refinery. Biodegradation experiments showed that this strain could degrade 500 mg/L of quinoline in growth medium completely within 32 h. The optimum degradation temperature, initial pH of growth medium and rotary speed of shaker for Q2 utilizing quinoline was 30 ℃, pH 8—10 and 100—200 r/min, respectively. The initial concentration of quinoline had great impact on the degradation by Q2, and this degradation process agreed with zero order kinetics equation when the initial concentration of quinoline in the range of 195—796 mg/L. During the biodegradation, the color of the medium changed from yellow to pink, and brown finally. FT-IR analysis exhibited that the degradation of quinoline was probably followed 8-hydroxycoumarin metabolic pathway, and that the nitrogen atom of heterocyclic compound was released as ammonium into the growth medium.

Key words: quinoline , biodegradation , kinetics , FT-IR, metabolic pathway