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

摘要:

【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。

Abstract:

[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.