[Isolation, identification, and biodegradation characteristics of a quinoline-degrading bacterium]

A bacterial strain BW003, which could utilize quinoline as sole carbon, nitrogen and energy source, was isolated from the activated sludge in a coking wastewater treatment plant. According to the 16S rRNA gene sequence analysis, the strain was identified as Pseudomonas sp. Biodegradation experiments showed that the strain could degrade 192-911 mg/L of quinoline efficiently within 3-8 h, and the removal rates of quinoline were ranged from 96% to 98%. The optimum conditions for the degradation were 30 degrees C and pH 8. Metabolic products analysis revealed that at least 43% quinoline was first transformed into 2-hydroxyquinoline, 0.69% 2-hydroxyquinoline was then transformed into 2,8-dihydroxyquinoline, and subsequently into 8-hydroxycoumarin in the process of biodegradation. Additionally, at least 48% of nitrogen in quinoline was transformed into NH3-N directly and external carbon source could promote the nitrogen transformation, demonstrating that the quinoline and its metabolic products could be eliminated if controlling proper C/N ratio.