蜡状芽孢杆菌HY-1降解甲基对硫磷和毒死蜱的影响因素研究

采用富集驯化培养和紫外分光光度计定量的方法,从农药生产企业的废水处理系统中分离筛选出1株能够降解甲基对硫磷和毒死蜱的蜡状芽孢杆菌（Bacilluscereus）HY-1,并系统研究了影响其降解甲基对硫磷和毒死蜱的主要因素。研究表明,菌株HY-1能够利用甲基对硫磷和毒死蜱为唯一磷源降解农药。HY-1降解甲基对硫磷的适宜条件为：培养温度30～35℃,pH为6～8,甲基对硫磷初始浓度为10～50mg·L^-1,接种量20%（体积比,菌体密度：稀释到菌悬母液（OD600=3.0）的0.8～1倍）,添加葡萄糖不能促进菌株对甲基对硫磷的降解。HY-1降解毒死蜱的适宜条件为：葡萄糖浓度6g·L^-1,培养温度30～35℃,pH为7.0,毒死蜱初始浓度80～200mg·L^-1,接种量20%（体积比,菌体密度：稀释到菌悬母液（OD600=3.0）的0.8～1倍）。结果表明,HY-1菌株降解甲基对硫磷和毒死蜱的适宜条件相类似,只是降解所需的最适葡萄糖浓度和底物浓度不同。

Degradative Characteristics of Bacillus cereus HY-1 to Methyl-parathion and Chlorpyrifos

A bacterial strain, Bacillus cereus HY-1, was isolated from the treatment system of the pesticide enterprises and its degradative characteristics to methyl-parathion and chlorpyrifos were studied by using the methods of enrichment culturing and the ultraviolet spectrophotometer determination. The results showed that the bacteria could utilize the methyl-parathion or chlorpyrifos as the unique phosphorus source. The optimal conditions for degrading methyl-parathion were as follows：the temperature of 30～35 ℃, the initial pH of 6～8, the initial methyl-parathion concentration of 10～50 mg·L^-1 and the inoculation amount of 20% in the experimen（tv/v）. The results also indicated that the optimal conditions for degrading chlorpyrifos was similar as above, except the different concentration of glucose or the substrate concentration.