1株壬基酚降解菌的分离鉴定及其降解特性研究

Isolation,Identification and Biodegradation Characteristics of A Bacterial Strain Able to Degrade Nonylphenol

从给水处理系统长期运行的颗粒活性炭上分离到1株可以以壬基酚(NP)为唯一碳源生长的好氧细菌F-10,利用Sherlock微生物鉴定系统(MIS)分析,初步鉴定为红球菌属中的红串红球菌.通过摇瓶实验考察了温度、pH、NP初始浓度、细菌投量、金属离子等因素对F-10降解NP性能的影响,得出最佳降解条件是温度30℃,pH值6.0,在该条件下,2%菌投量对1 mg/L NP去除率达到了62%,且降解过程满足一级动力学模型,速率常数(k)为0.086 5 d-1,半衰期(t1/2)为8.0 d;此外,菌的降解速率与NP的初始浓度关系不大,而与菌量呈正相关;增加溶液中NH4+、Mn2+、Mg2+、NaCl浓度或加入葡萄糖、醋酸钠和酵母膏等底物对菌降解NP均有促进作用;而Ca2+、Cu2+、Fe2+和磷酸盐的作用则相反;同时混合菌体系的降解性能要优于纯菌.

A bacteria strain F-10 was isolated from activated carbon, which was processed with sand filtered water from Songhua River for a long time, pre-oxidized with ozone, PPC and ferrate. The bacterial strain was capable of utilizing nonylphenol （NP） as sole carbon source and identified as Rhodococcus erythropolis with the Sherlock Microbial Identification System （MIS） from the MIDI Corporation. The optimal conditions for NP biodegradation in the shaking flasks were at 30℃ and pH 6.0. Under those conditions, NP at concentration of 1 mg/L was biodegraded by 62% with 2% of inoculum amount. The biodegradation reaction fitted well with first-order kinetic model, with a degradation rate constants （k） of 0.086 5 d^-1 and half-lives （t1/2） of 8.0 d. Aerobic degradation rate for NP was enhanced by increased level of NH4^＋ , Mn^2＋ , Mg^2＋ , and NaCl, and by addition of glucose, NaAc, and yeast extract as well as by reduced level of Ca^2＋ , Cu^2＋ , Fe^2＋, and phosphate, while no apparent effect of original NP concentration was observed. The combination of F-10 with other 27 bacterial strains which were also isolated from activated carbon expressed better biodegradation effectiveness.