非离子表面活性剂强化白腐菌及其粗酶液对有机氯农药的降解

Effects of nonionic surfactants on degradation of organochlorine pesticides by white rot fungus and its enzyme

有机氯农药曾在世界范围内被广泛用于农业害虫的防治,为利用表面活性剂增效修复技术去除环境中的有机氯农药污染,研究了3种非离子表面活性剂(Tween 80、Tween 20和Triton X-100)对4种典型有机氯农药(4,4’-DDT、狄氏剂、艾氏剂和七氯)在水相中的增溶作用,对白腐菌Phlebia acanthocystis TMIC34875生长的影响以及对该菌株、胞外及胞内酶降解有机氯农药的强化效果.增溶试验结果表明,3种非离子表面活性剂可明显增加各有机氯农药的水溶解度,其增溶能力大小顺序为Tween 80>Tween 20>Triton X-100.Tween 80在低浓度(0.05、0.1和0.2 gL-1)下会促进白腐菌在PDB培养基中的生长,使其生物量增加;而高浓度(0.5和1.0 gL-1)的Tween 80则对菌株的生长产生一定的抑制作用.在0.05-0.5 g L-1浓度范围内,Tween 80可强化菌株对有机氯农药的降解效果,且降解率随着Tween 80浓度的增加而增加.降解强化效果在Tween 80浓度为0.5 gL-1时达到最佳,4,4’-DDT、狄氏剂、艾氏剂和七氯的降解率相比对照分别提高了6.70%、6.37%、10.94%和7.21%.Tween 80同样可促进胞内酶和胞外酶对4种有机氯农药的降解,尤其是对胞外酶降解的强化作用,在1.0 gL-1的Tween 80溶液中,有机氯农药的降解率提高了10%左右.可见,在农药污染环境的生物修复技术中,应用Tween 80等非离子表面活性剂来提高修复效率是可行的.

In order to explore the enhancing effect of surfactants on biodegradation of organochlorine pesticides（OCPs）,this research investigated the effects of nonionic surfactants on solubilization of OCPs,the growth of white rot fungus Phlebia acanthocystis TMIC34875,and the biodegradation of OCPs by the fungus as well as its extracellular and intracellular enzymes.The results indicated that the solubility of OCPs in water could be greatly enhanced by the three nonionic surfactants,with the sequence of OCPs solubility enhancement as Tween〉 80 Tween20 〉Triton X-100.Among them Tween 80 of 0.05,0.1 and 0.2g L^-1 concentrations had positive effects on fungal growth,but that of higher concentrations（0.5 and 1.0 g L^-1 inhibited the fungal growth in PDB medium.Tween 80 could effectively increase the fungal degradation of OCPs at a concentration range of 0.05 to 0.5 g L^-1,with the degradation rate increasing with Tween 80 concentration.The enhancing effect was the greatest with Tween 80 concentration of 0.5 g L^-1,when the degradation efficiency was 6.70%,6.37%,10.94% and 7.21% for 4,4＇-DDT,dieldrin,aldrin and heptachlor,respectively,higher than that of the control culture.It was also found that Tween 80 could enhance the degradation of OCPs by extracellular or intracellular enzymes from P.acanthocystis TMIC34875,notably by about 10% with extracellular enzyme under 1.0 g L^-1 Tween 80.These results indicated that Tween 80 has considerable potential for the bioremediation of OCPs-polluted environments.