固定化降解菌Q5降解喹啉动力学

通过富集培养的方法从石油污染的土壤中筛选到1株以喹啉为唯一碳源和氮源的菌种Q5，鉴定为Lactobacillus fermentum。通过将菌种Q5固定在纳米SiO₂载体上制成固定化微生物，对其降解喹啉的效果及动力学进行研究。结果表明，菌株Q5经固定化后，对喹啉的降解能力大大增强，在500 mg/l浓度下，40h固定化Q5对底物降解率达96.6%，远高于未固定化Q5的降解率56.1%；对于高底物浓度，固定化Q5仍表现出理想的降解效果，初始底物浓度为1500 mg/l，反应70h后降解率为91.6%。对其降解喹啉的动力学的研究表明，在喹啉浓度为500 mg/l、1000 mg/l、1500 mg/l时，降解动力学方程遵循一级反应，降解速率常数随着喹啉初始浓度的升高而减小，当喹啉浓度为500 mg/l时，固定化Q5的降解速率常数为0.089 h-1，远高于未固定化Q5的降解速率常数0.034 h-1。

THE KINETICS OF IMMOBILIZED BACTERIA Q5 DEGRADING QUINOLINE

A bacteria strain Q5 which used quinoline as sole source of carbon and nitrogen was isolated from petroleum contaminated soil by enrichment and identified as Lactobacillus fermentum. The degrading effect and kinetics of it to quinoline were studied in this article by fixing it on nano- SiO2 carrier and making into immobilized microorganism. It was shown that the degrading ability of bacteria strain Q5 was enhanced drastically after immobilized. The degrading rate could reach 96.6% with Q5 immobilization after 40h reaction at 500 mg/l quinoline concentration, higher than the un-immobilized bacteria strain Q5 (56.1%), the degrading effect was also perfect (91.6% after 70h reaction) in high substrate concentration (1500 mg/l). The research of it degrading quinoline's kinetics was shown that the biodegradation followed the first-order model. The rate constant decreased with the increase of quinoline initial concentration at the concentration of 500, 1000, 1500 mg/l. When the concentration of quinoline was 500 mg/l, the degrading rate constant of immobilized Q5 was 0.089 h-1, which was higher than un-immobilized Q5 0.034 h-1.