一株喹啉降解菌的降解特性及代谢途径研究

从某石化厂污水处理站厂区内受石油污染的土壤中分离出1株能以喹啉为唯一碳源、氮源和能源生长代谢的菌株Q2。降解试验结果表明，Q2能将喹啉质量浓度为500 mg/L的培养液中的喹啉在32 h内完全去除，其降解喹啉的适宜温度为30 ℃、培养基初始pH值为8~10、摇床转速为100~200 r/min；喹啉浓度对Q2的降解有较大影响，喹啉质量浓度为195~796 mg/L时，Q2降解喹啉的过程符合零级动力学方程。生物降解过程中，培养液从黄色变为粉红色，最后呈棕色。红外光谱分析显示，Q2降解途径很可能为8-羟基香豆素途径，且杂环上氮原子以氨氮的形式释放。

BIODEGRADATION CHARACTERISTICS AND METABOLIC PATHWAY OF A STRAIN FOR QUINOLINE DEGRADATION

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.