两株喹啉降解菌代谢途径的分析

Metabolic pathway analysis of two quinoline-degrading bacterial strains.

从焦化废水处理系统中分离得到2株以喹啉为唯一碳源和氮源生长代谢的降解菌,经形态、生理生化特征及16S rRNA基因的序列分析初步鉴定为Pseudomonas sp.QG6和Rhodococcus sp.QL2.2株菌对喹啉均表现出良好的降解性能,当喹啉初始浓度为150mg/L时,均能在8h内降解完全.QG6对TOC去除率高于QL2.采用HPLC检测到2株菌的中间产物不尽相同,所有被检出的中间产物均比喹啉极性强.GC/MS鉴定结果显示,QG6的中间产物有2-羟基喹啉、8-羟基香豆素和2,3-二羟基苯丙酸,QL2的中间产物包括2-羟基喹啉、2,6-二羟基喹啉和8-羟基香豆素.探讨了降解喹啉的2条不同代谢途径.

Two degrading bacterial strains utilizing quinoline as sole carbon source and nitrogen source for growth and supersession were isolated from coking wastewater treatment system. Based on their morphology, physiological and biochemical characters, and sequence analysis of 16S rRNA genes, two bacterial strains were initially identified as Pseudomonas sp. QG6 and Rhodococcus sp, QL2, respectively. Both strains showed good biodegradability for quinoline. They could both degrade completely in 8h when quinoline initial concentration was 150mg/L. but in degrading process showed different color change, and on TOC removal efficiency strain QG6 was higher than strain QL2. HPLC analysis showed that the intermediates of quinoline degradation by two strains were different and the polarities of these intermediates were stronger than that of quinoline. GC/MS appraisal results showed that the intermediates oT Pseudomonas sp. QG6 had 2-hydroxyquinoline, 8-hydroxycoumarin, and 2, 3-dihydroxyphenylpropionic acid, whereas the intermediates of Rhodococcus sp. QL2 included 2-hydroxyquinoline, 2,6-dihydroxyquinoline, and 8-hydroxycoumarin At last, two different metabolic pathways of quinoline degradation were proposed.