摘要
A strain Pseudomonas sp.PP1 was isolated from activated sludge and characterized by morphological observation,biochemical and physiological identification as well as 16 S rRNA gene sequence analysis.It was a gram-negative,non-motile,rod-shaped with colonies which were white,opaque,small and wrinkled on solid quinoline-MSM.The strain was negative for catalase,gelatin liquefaction,M.R and V.P tests and was unable to reduce / restore nitrate.The 1406 bp 16 S rRNA gene fragment of PP1 was more than 99% identical to the Pseudomonas sp.Biodegradation of quinoline as single substrate was conducted in batch experiments at different temperatures( 15- 40 ℃) and p H values( 5- 10).The results indicate that the optimum conditions for the degradation of quinoline by PP1 were 30 ℃ and p H 7.Pseudomonas sp.PP1 was able to degrade 97.1%,95.4%,94.8%,63.6% and 40.4% quinoline when initial concentrations of quinoline were 50,100,200,300,and 400 mg / L,respectively,and lag phases were prolonged from 2 h to 10 h.The maximum degradation rate( q) was obtained at an initial quinoline concentration( S0) of about 100 mg/L with q of 0.082.The experimentally obtained q values at various initial S0 were fitted by Haldane model,Yano model,Aiba model,Edward model and Webb model,and the results demonstrated that Haldane model gives the best fit for strain PP1 with coefficient of determination,R2= 0.9124 and SDavg= 0.0113208.Five metabolic intermediates were identified by high performance liquid chromatograph( HPLC) and GC / MS.Finally,a possible pathway containing 5,6-dihydroxy-2-oxo-1,2-dihydroquinoline as an intermediate was proposed for the first time.
A strain Pseudomonas sp.PP1 was isolated from activated sludge and characterized by morphological observation,biochemical and physiological identification as well as 16 S rRNA gene sequence analysis.It was a gram-negative,non-motile,rod-shaped with colonies which were white,opaque,small and wrinkled on solid quinoline-MSM.The strain was negative for catalase,gelatin liquefaction,M.R and V.P tests and was unable to reduce / restore nitrate.The 1406 bp 16 S rRNA gene fragment of PP1 was more than 99% identical to the Pseudomonas sp.Biodegradation of quinoline as single substrate was conducted in batch experiments at different temperatures（ 15- 40 ℃） and p H values（ 5- 10）.The results indicate that the optimum conditions for the degradation of quinoline by PP1 were 30 ℃ and p H 7.Pseudomonas sp.PP1 was able to degrade 97.1%,95.4%,94.8%,63.6% and 40.4% quinoline when initial concentrations of quinoline were 50,100,200,300,and 400 mg / L,respectively,and lag phases were prolonged from 2 h to 10 h.The maximum degradation rate（ q） was obtained at an initial quinoline concentration（ S0） of about 100 mg/L with q of 0.082.The experimentally obtained q values at various initial S0 were fitted by Haldane model,Yano model,Aiba model,Edward model and Webb model,and the results demonstrated that Haldane model gives the best fit for strain PP1 with coefficient of determination,R^2= 0.9124 and SDavg= 0.0113208.Five metabolic intermediates were identified by high performance liquid chromatograph（ HPLC） and GC / MS.Finally,a possible pathway containing 5,6-dihydroxy-2-oxo-1,2-dihydroquinoline as an intermediate was proposed for the first time.
