白腐菌Phlebia brevispora TMIC34596对林丹的酶促降解特性  

Enzymatic degradation of lindane by white rot fungus Phlebia brevispora TMIC34596

作　　者：肖鹏飞[1] 秦必达 王剑桥[2] 

机构地区：[1]东北林业大学林学院,哈尔滨150040 [2]静冈大学农学院

出　　处：《安全与环境学报》2014年第6期161-164,共4页Journal of Safety and Environment

基　　金：国家自然科学基金项目(41201307);教育部留学回国人员科研启动基金项目([2013]693);人社部留学人员科技活动择优资助项目

摘　　要：为了阐明白腐菌株Phlebia brevispora TMIC34596对有机氯杀虫剂林丹的酶促降解机理及规律,在实验室条件下,通过菌株的纯培养、超声波破碎和高速离心等过程,提取到胞内粗酶液和胞外粗酶液,并研究了胞内及胞外酶对林丹的降解特性、最佳降解条件及动力学参数等。结果表明,胞内酶起主要的降解催化作用,相同处理时间内对林丹的降解率是胞外酶的4~5倍。胞内酶降解林丹的酶促反应最适温度为35℃,最适p H值为5.0,最适条件下反应2 h后的林丹降解率为64.0%。胞内酶在25~40℃、p H值在4.0~6.5时能保持较高的降解活性,对林丹的降解率在50%以上。胞内酶降解林丹的米氏常数Km为1.30μmol/L,最大反应速率Vmax为1.18μmol/min,表明胞内酶对林丹有较强的亲和力,降解林丹速度较快。通过气相色谱-质谱分析,五氯环己醇和四氯环己二醇被鉴定为林丹的胞内酶代谢产物,表明胞内酶可通过连续的脱氯及羟基化作用将林丹转化为多羟基化产物,该途径不同于目前所报道的白腐菌对林丹的降解途径。The paper intends to study the enzymatic degradation of lindane by white rot fungus Phlebia brevispora TMIC34596. As is known, lindane is an organochlorine insecticide that was extensively used for controlling the agricultural pests in the past few decades in China. The principal reason for its successful removal and elimination of lindane from the contaminated environment is its capacity for microbial transformation and degradation. In order for lindane to effectively carry out the removing effect of the contaminants, it is necessary to study primarily the microbial enzymatic degradation through laboratory simulation. In so doing, we have done our experiments with Phlebia brevispora TMIC34596 for its effective function to degrade chlordane. And, for our experiments, we have also prepared the inner and extra-cell crude enzyme from the white rot fungus by way of pure culture, ultrasonic fragmentation and centrifuge separation. The results of our experiments show that lindane （20 μmol/L） can be removed at about 57.1% and 12.2% by intracellular crude enzyme and extraeellular crude enzyme during 2 h, respectively, indicating that the degrading enzyme produced from the said fungus is the intracellular one. The degradation activity of lindane by the intra- cellular enzyme has been found irffluenced by the pH value, tempera- ture, and the concentration of lindane. We have also found that the intracellular enzyme is able to keep the high degradation activity （ 〉 50 % ） of lindane when the pH ranges from 4.0 to 6.5, and that of temperature from 25 ~C to 40 ~C, which demonstrates that the de- grading enzyme enjoys broader pH and thermal stability. The optimal temperature and pH value for the intracellular enzymatic degradation of lindane should be 35℃ and 5.0. At the same time, the Michaelis-Mentn＇ s constant （Km） of the degrading enzyme is 1.30 vmoL/L and the maximal degradation rate （Vm^x） for the degradation of lindane by intracellular enzyme is 1.18 μmol/min. Thus, from the GC/MS analysis, it is

关 键 词：环境工程学 林丹 白腐菌 酶促降解 降解条件 

分 类 号：X592[环境科学与工程—环境工程]