Bacillus cereus HY-4对有机磷农药毒死蜱的降解特性

Degradation Characteristics of Bacillus cereus HY-4 to Organic Phosphorus Pesticide Chlorpyrifos

目的:明确一株蜡状芽孢杆菌(Bacillus cereus HY-4)对毒死蜱的降解特性。方法:采用UV全波长扫描、灵敏度和添加回收率测定等建立了毒死蜱的定量检测方法,以及通过定量添加毒死蜱和降解菌的方法研究了菌株HY-4对毒死蜱的降解特性。结果:毒死蜱的最佳测定波长为292.0 nm,经验证该检测方法的线性相关性、灵敏度、准确度和变异系数均符合菌株降解毒死蜱残留检测的要求。降解菌HY-4对50.0mg/L毒死蜱的降解率在摇培36 h时达到最高,适量添加葡萄糖能够促进降解菌的生长和毒死蜱的降解,葡萄糖添加量为0.5%时对50.0 mg/L毒死蜱的降解率达最高为88.0%;毒死蜱初始浓度对降解率也有较大影响,毒死蜱初始浓度为50.0 mg/L时降解率达最高为89.6%,然而当毒死蜱初始浓度继续升高时,菌株对毒死蜱的降解率下降,毒死蜱初始浓度为200.0 mg/L时,降解率下降至59.3%。结论:降解菌HY-4对毒死蜱的降解能力较强,在毒死蜱污染水体等的微生物降解方面应用价值较大。

Objective： To explore the degradation characteristics of Bacillus cereus HY-4 to chlorpyrifos. Methods：The UV quantitative method was established by UV scan,sensitivity test and recovery rate measurement. Furthermore,the characteristics of biodegradation were quantified by adding chlorpyrifos and degrading bacteria together to mineral medium and analyzing chlorpyrifos residue at a definite time. Results： It showed that the suitable ultraviolet absorption band was selected as λ = 292. 0 nm and the linear regression equation between the absorbance and chlorpyrifos concentration was y = 0. 0176 x-0. 003（ R2= 0. 999 4）,the minimum detection concentration of chlorpyrifos was 0. 20 mg/L,the percentage accuracy of the analysis method was from 95. 3 % to107. 0 %,the coefficient of variation was between 3. 5 % and 4. 2 %. Therefore,the sensitivity and coefficient of variation could meet the requirements of the detection of chlorpyrifos residue. The degradation curve indicated that the degradation rate of chlorpyrifos reached maximum at 36 h,degradation of chlorpyrifos was accompanied by the proliferation of bacteria. Adding a certain concentration of glucose could promote the growth of bacteriaand degradation rate of chlorpyrifos,it can be speculated that the addition of a certain concentration of glucose could make rapid growth of bacteria and shorten the lag phase of chlorpyrifos degradation. The degradation rate of chlorpyrifos reached 88. 0 % as the glucose concentration was 0. 5 %. The initial concentration of chlorpyrifos had great effect on the degradation rate and the degradation rate achieved 89. 6 % as the initial concentration of chlorpyrifos reached 50. 0 mg/L. However,when chlorpyrifos concentrations continuing to increase,the degradation rate of chlorpyrifos began to decline,the degradation rate reduced to 59. 3 % as the concentration reached 200 mg/L. Conclusion： The ability of the strain on degradation of chlorpyrifos was excellent and had great application value on the microbial degradation of chlorpyrifos in polluted area.