一株溴氰菊酯降解菌的分离鉴定及其降解条件优化

【背景】拟除虫菊酯类农药的降解已成为食品安全和环境卫生领域的研究热点,而生物降解被认为是一种绿色高效的解决方法。【目的】从长期受拟除虫菊酯类农药污染的草莓根系土壤分离一株溴氰菊酯(deltamethrin,DM)降解菌,并优化其培养基及降解条件,从而提高DM降解菌的降解效率。【方法】采用富集驯化、分离纯化法筛选DM降解菌,通过形态学和生理生化特征,以及16S rRNA基因序列分析进行鉴定。通过Plackett-Burman因素筛选试验、最陡爬坡试验和Box-Behnken试验优化菌株降解条件。【结果】筛选获得一株DM降解菌LH-1-1,96h对DM(100mg/L)的降解率为53.43%,经鉴定为琼氏不动杆菌(Acinetobacter junii);通过优化后,在DM浓度75mg/L、胰蛋白胨3 g/L、pH值6.8、硫酸铵1.5 g/L、氯化铁0.01 g/L、接种量为5%(体积比)、菌龄12 h、培养温度30℃条件下,菌株LH-1-1对DM降解率达82.36%,较未优化前提高了28.93%。【结论】A. junii LH-1-1具有较高的DM降解能力,该菌可为生物修复受DM或拟除...

Isolation, identification and optimization of degradation conditions of a deltamethrin degrading strain

[Background] The degradation of pyrethroid pesticides is important for food safety and environmental health, and biodegradation is considered to be a green effective solution. [Objective] The strain with high ability to degrade deltamethrin (DM) was isolated from strawberry rhizosphere contaminated soil by pyrethroid pesticides for a long term, and the degradation rate of DM degrading strain was improved by optimizing the medium and degradation conditions. [Methods] DM degrading strain was screened by enrichment domestication, isolation, purification and identified by morphological, physio-biochemical, 16S rRNA sequence analysis. The degradation conditions were optimized by Plackett-Burman design, steepest ascent path design and Box-Behnken design. [Results] Strain LH-1-1 was identified as Acinetobacter junii, it could degrade 53.43% DM (100 mg/L) within 96 h in initial conditions. The optimized conditions were DM concentration 75 mg/L, tryptone 3 g/L, pH 6.8, (NH4)2SO4 1.5 g/L, FeCl3 0.01 g/L, inoculation biomass 5%, strain age 12 h, culture temperature 30 °C. The degradation rate of DM under these conditions reached 82.36% within 96 h, which was 28.93% higher than initial conditions. [Conclusion] A. junii LH-1-1, a highly efficient DM degrading strain, can be used as excellent microbial resources for bioremediation of environment polluted by DM or pyrethroid pesticides.