阿维菌素降解菌的分离鉴定及降解特性研究

[目的]分离阿维菌素降解菌为土壤农药污染修复提供理论依据和物质基础。[方法]从长期受阿维菌素污染的某制药厂沉淀池底泥中分离出了3株能高效降解阿维菌素的菌株,利用16S rDNA序列分析法对其进行鉴定,并对其降解特性进行研究,最后进行了土壤模拟降解试验。[结果]经鉴定,3株细菌分别为枯草芽孢杆菌、黏质沙雷氏菌和蜡样芽孢杆菌。枯草芽孢杆菌降解阿维菌素的最适pH值和温度分别为6.0和35 ℃,在装样量80 mL、细菌接种量0.1%(体积分数)、底物含量100 mg？L-1条件下降解速率最佳,添加0.2%的蔗糖和酵母浸液可促进阿维菌素的降解;黏质沙雷氏菌降解阿维菌素的最适pH值和温度分别为6.0和40 ℃,在装样量60 mL、细菌接种量0.05%、底物含量150 mg？L-1条件下降解速率最佳,添加0.2%的蔗糖和牛肉膏可促进阿维菌素的降解;蜡样芽孢杆菌降解阿维菌素的最适pH值和温度分别为6.0和40 ℃,在装样量120 mL、细菌接种量0.1%、底物含量150 mg？L-1条件下降解速率最佳,添加0.2%的淀粉和酵母浸液可促进阿维菌素的降解。试验结果还表明:添加少量Fe3+、Cu2+可显著提高阿维菌素的降解速率,其中以Cu2+最为明显。土壤模拟降解试验结果表明土壤中添加高效降解菌会显著加快阿维菌素的降解。[结论]试验所得3株菌株在土壤修复方面具有很好的应用前景。
[Objectives]The aim of the study is to isolate avermectin-degrading bacteria,for repairing the soil pesticide pollutants. [Methods]Three efficient degradation bacteria of avermectin(AVM)from the soils near a pharmaceutical factory were isolated and identified as Bacillus subtilis,Bacillus prodigiosus and Bacillus cereus,respectively by sequencing 16S rDNA. After that,the degradation characteristics were studied. [Results]The results showed that the optical conditions of B.subtilis for degrading AVM as follows:pH6,35 ℃,ventilatory capacity of 80 mL,bacterial load of 0.1% and substrate at concentration of 100 mg？L-1,and the degrading effect could be accelerated if sucrose and yeast extract of 0.2% were added. For B.prodigiosus,the best conditions were pH6,40 ℃,ventilatory capacity of 60 mL,bacterial load of 0.05% and substrate at concentration of 150 mg？L-1,while adding sucrose and beef extract of 0.2% can accelerate the degradation of AVM. B.cereus showed strong degradation ability under the conditions of pH6,40 ℃,ventilatory capacity of 120 mL,bacterial load of 0.1% and concentration of substrate at 150 mg？L-1 similarly,adding starch and yeast extract of 0.2% can accelerate the degradation of AVM. The degradation of AVM can be significantly improved by Fe3+ and Cu2+,especially Cu2+. The degradation of AVM was faster after adding these three efficient bacteria in the soil. [Conclusions]The results indicated that the three strains have a great potential for using to repair the soil