蚯触圈源啶虫脒降解菌D35的分离鉴定及其降解条件优化

Isolation,identification,and optimization of degradation conditions of the acetamiprid-degrading strain D35 from drilosphere

【背景】啶虫脒等新烟碱类杀虫剂的残留易对非靶标生物造成伤害,投加高效降解细菌进行生物强化,可促进其快速降解。【目的】从蚯触圈中分离筛选啶虫脒降解菌并优化其降解条件,提高降解效率。【方法】制备蚯触圈基质富集筛选降解菌;通过生理生化特征和16S rRNA基因序列分析对其进行鉴定;利用单因素筛选、Plackett-Burman试验、最陡爬坡试验及Box-Behnken design试验优化菌株降解条件。【结果】分离得到1株啶虫脒降解菌D35,可在72 h内降解55.46%初始浓度为50 mg/L的啶虫脒,将其鉴定为一株假单胞菌(Pseudomonas sp.)。优化得到菌株降解啶虫脒的最佳环境条件为:胰蛋白胨10.19 g/L、温度为30℃、接种量为5.24%,pH 7.0、初始农药浓度50 mg/L,在此条件下72 h内菌株降解率为80.21%,较未优化前提高了24.75%。【结论】本研究对分离筛选新烟碱类杀虫剂降解菌的方法进行了探索,获得的菌株D35可高效降解啶虫脒,为快速消除环境中啶虫脒污染提供了新的微生物资源。

[Background]The residues of acetamiprid and other neonicotinoid insecticides have adverse effects on non-target beneficial organisms,and bacteria can promote the degradation of them.[Objective]To isolate acetamiprid-degrading strain from drilosphere and optimize the degradation conditions to improve the degradation rate.[Methods]The acetamiprid-degrading strain was isolated from drilosphere and identified based on 16S rRNA gene sequencing and physiological and biochemical characteristics.The degradation conditions were optimized by single factor test,Plackett-Burman design,steepest ascent path design,and Box-Behnken design.[Results]Strain D35 could degrade more than 55.46%of 50 mg/L acetamiprid within 72 h,and was identified as Pseudomonas sp.The optimized conditions were tryptone 10.19 g/L,30℃,inoculum size 5.24%,pH 7.0,and acetamiprid at initial concentration of 50 mg/L.The degradation rate of D35 under the optimized conditions hit 80.21%within 72 h,24.75%higher than that before the optimization.[Conclusion]We screened the neonicotinoids-degrading bacteria and strain D35 could efficiently degrade acetamiprid,which provided microbial resource for rapidly eliminating acetamiprid in the environment.