一株苯乙烯高效降解菌的分离鉴定及降解特性研究

从某橡胶厂的活性污泥中筛选得到一株可高效降解苯乙烯的微生物菌株WJ,通过透射电镜(TEM)、生理生化试验、Biolog鉴定和16S rRNA基因的系统发育树建立等分析方法,鉴定该菌株为恶臭假单胞菌(Pseudomonas putida).通过环境单因素试验,确定该菌株WJ在温度30℃、pH值7.0的培养条件下具有良好的降解效果.通过不同初始浓度苯乙烯的降解及生长特性,确定该菌株的最大底物耐受浓度达到1500mg/L,且其生长动力学过程符合Haldane’s方程,相应动力学参数为: vmax=0.282h-1,Ks=23.57mg/L,Ki=1784.56mg/L.底物宽泛性试验表明,该菌株对苯系物(BTEX)、正己烯等与苯乙烯结构类似的碳氢化合物都具有良好的降解能力,表明其具备良好的底物宽泛性.该菌株对苯乙烯的氧化降解途径主要为乙烯基侧链的氧化.

Identification and characteristics of a Pseudomonas putida strain with the capable of efficiently degrade styrene.

A bacterium (strain WJ) capable of efficiently degrading styrene was isolated from the activated sludge of a rubber plant. According to its morphology, physiological-biochemical properties and its16S rRNA gene sequence analysis, the strain was identified as Pseudomonas putida. The single-factor test showed that the optimum temperature and pH for its growth and styrene-degradation were 30℃ and 7.0, respectively. Strain WJ could efficiently degrade various concentration of styrene, and the maximum tolerated concentration was 1500mg/L. Haldane's model could be fit to the kinetics data well and its degradation kinetics parameters listed as below: vmax=0.282h-1, Ks=23.57mg/L, Ki=1784.56mg/L. The strain WJ could biodegrade several hydrocarbons (such as BTEX, n-hexene), which were characterized with similar structures to that of styrene. Analysis of metabolic products showed that the main degradation pathway of styrene by strain WJ was the oxidation of oxyethylene chain.