五氯酚(PCP)高效降解菌Psendomonas sp.CS5的研究

STUDIES ON PSENDOMONAS SP. CS5 THAT DEGRADES HIGH CONCENTRATION OF PENTACHOROPHENOL *

从曾受五氯酚 (pentachlorophenol,简称PCP ,下同 )污染废水的活性污泥中 ,经驯化富集和分离筛选获得一株PCP降解菌 ,菌号为CS W 98 5 .在 2 4h内该菌降解w(PCP) =40 0× 10 -6达 90 %以上 .该菌短杆状 ,大小为0 .6～ 0 .8μm× 0 .9～ 1.2 μm ,无芽孢 ,一端生单鞭毛 ;革兰氏染色阴性 ,好氧 ,氧化酶阳性 ,接触酶阳性 ;最适生长温度为 2 8℃ ,最适生长pH为 6 .5～ 8.0 .根据以上结果将该菌归于假单胞菌属 (Pseadomonassp .) .该菌对c(Na Cl) =0 .2mol/L以上敏感 ;在pH 7.0～ 9.0、2 8℃和大生物量条件下能有效地降解高浓度PCP ;在该菌降解PCP时 ,添加某些营养物如牛肉膏、葡萄糖有利于PCP的降解 .在检测CS W 98 5菌脱氯酶基因 (pcpB基因 )时 ,分子杂交结果表明其与对照菌Sphingomonassp .RA2的pcpB基因有同源性 ;但PCR结果显示该基因与pcpB基因存在差异 .这表明CS W 98 5菌与Sphingomonassp .RA2有亲缘性关系但又不完全相同 .图 9表 4参

A pentachlorophenol degrading bacteria was isolated from sewage sludge containing PCP waste after enrichment. Main characteriseics of CS W 98 5 strain are Gram negative,single polar flagelled,oxidase and catalase positive.It was identified as Psendomonas sp. by morphological,physiological and biochemical characteristics.It could use PCP as sole source of carbon and energy. CS W 98 5 strain was able to degrade a higher concentration of PCP than previously reported PCP degrading bacteria. The degradation percentage was over 90% within 24 h. pH 6.5～8.0 and 28 ℃ were the optimum conditions for growth, while the optimum conditions for degradtion were 28 ℃,pH 7.0～9.0. The strain was very sentitive to sodium chloride. CS W 98 5 strain required multiple inoculations for effective degradation of PCP. It could also utilize 2,4,6 trichlorphenol, 2,3,4,6 tetrachlorphenol, and Cl OPA. Natrient amendmend affected PCP degradation.Induction could also increase PCP degrading rate. The PCP 4 monooxygenase gene( pcp B gene) was analyzed for this strain and Sphingomonas sp. RA2 by PCR and hybridization. The results of hybridization verified the similarity of PCP degrading genes of these strains, but the results of PCR showed the difference exiting between these two strains. Fig 9, Tab 4, Ref 10