炔草酯降解菌Sphingopyxis sp. WP68的分离鉴定与降解特性

【背景】炔草酯可以高效防除麦田恶性杂草,但炔草酯的生产和使用也对环境造成了破坏,对动物和人类健康造成了威胁。【目的】分离筛选炔草酯高效降解菌株,研究其降解特性,为炔草酯污染生物修复提供优良菌种资源。【方法】采集农药厂活性污泥样品,通过富集培养和含有炔草酯的LB培养基进行炔草酯降解菌株的分离,通过形态和生理生化特性以及16S rRNA基因序列分析确定其分类学地位,通过单因素试验从温度、pH、接种量和底物浓度等方面考察菌株对炔草酯的降解特性,并利用UPLC-MS分析降解产物。【结果】筛选出一株炔草酯高效降解菌株WP68,经鉴定为鞘氨醇盒菌(Sphingopyxis sp.),该菌株在37°C和pH值为8.0时,10 h内可将200 mg/L的炔草酯降解98.26%。利用UPLC-MS鉴定菌株WP68降解炔草酯的产物为炔草酸。确定了该菌株降解炔草酯的最适温度、pH值、接种量、底物浓度分别是37°C、8.0、5%、200mg/L。菌株WP68还能降解氰氟草酯和精喹禾灵。【结论】Sphingopyxis sp. WP68对炔草酯有较强的降解能力和较高耐受性,在炔草酯污染土壤修复中具有潜在的应用前景。

Isolation, identification and characterization of clodinafop-propargyl degrading Sphingopyxis sp. WP68

Background] Although clodinafop-propargyl (CP) can efficiently control malignant weeds in wheat field, the producing and using of CP cause damage to the environment, and pose a threat to the health of animal and human. Objective] We isolated an efficient CP-degrading bacterium and studied its degradation characteristics to provide microbial resource for bioremediation of CP pollution. Methods] The active sludge sample was collected from a pesticide factory. The CP-degrading bacterium was isolated by enrichment cultivation and Luria-Bertani (LB) medium containing CP, and identified by morphological, physiological characteristics and analysis of 16S rRNA gene sequence. Single factor experiments were used to evaluate the degradation characteristics including temperature, pH, inoculum, substrate concentration. The degradation product of CP was identified by UPLC-MS. Results] An efficient CP-degrading strain WP68 was isolated and identified as Sphingopyxis sp.. Strain WP68 was able to degrade 98.26% of 200 mg/L of CP within 10 h under the condition of 37 °C and pH value of 8.0. The optimal culture conditions for strain WP68 degrading CP were temperature 37 °C, pH 8.0, inoculum 5%, and substrate concentration 200 mg/L. The degradation product of CP was identified as clodinafop acid (CA) by UPLC-MS. Strain WP68 was also capable of degrading cyhalofop-butyl and quizalofop-p-ethyl. Conclusion] Based on the high efficient degradation ability and high CP-tolerance, Sphingopyxis sp. WP68 has the potential prospect in bioremediation of CP-contaminated soil.