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赵卫松,徐莉,邱立红,郭庆港,鹿秀云,李社增,王培培,张晓云,马平.噻吩磺隆降解菌Staphylococcus sp.的分离及其降解特性与途径[J].环境科学学报,2017,37(2):585-595

Isolation and characterization of a thifensulfuron-methyl-degrading strain Staphylococcus sp. and the degradation pathways of TSM

基金项目：国家自然科学基金（No.31272085）；河北省自然科学基金（No.C2016301069）；河北省农林科学院博士基金项目（No.494-0701-YBN-K9UA）

摘要：采用富集培养技术从磺酰脲类除草剂污染土壤中筛选得到1株降解噻吩磺隆的细菌，命名为ZWS13.经形态特征和16S rRNA基因序列分析，初步鉴定为葡萄球菌属（Staphylococcus sp.）.采用HPLC研究了初始底物浓度、温度、接种量、pH等因素对菌株ZWS13降解噻吩磺隆的影响.结果表明，菌株ZWS13对噻吩磺隆的降解具有较广的底物浓度范围，在7 d内对初始浓度5.0~100.0 mg·L^-1噻吩磺隆的降解率达到60%以上；菌株ZWS13降解噻吩磺隆的较适pH为8.0，较适温度为40℃，较适接种量为1%；其中，菌株培养温度为40℃时，菌株在10 d内对50.0 mg·L^-1噻吩磺隆的降解率达到99%以上.降解谱测定结果表明，菌株对烟嘧磺隆、吡嘧磺隆和甲磺隆亦具有良好的降解效果.采用HPLC-MS分析确定了菌株对噻吩磺隆的5个降解产物，推测菌株对噻吩磺隆的降解途径主要为磺酰脲桥C-N键的断裂、脱甲基作用或脱酯作用的甲基丢失及三嗪环的开裂.研究表明，菌株ZWS13能够有效地降解噻吩磺隆，具有生物修复噻吩磺隆污染的潜力.

Abstract：A bacterial strain ZWS13, which could degrade thifensulfuron-methyl (TSM), was isolated from sulfonylurea herbicides contaminated soil by culture enrichment. Strain ZWS13 was identified as Staphylococcus sp., based on its morphology and 16S rRNA gene analysis. The effects of initial concentration of TSM, pH, temperature and inoculation size on degradation of TSM were investigated. TSM could be degraded over a broad range of its initial concentration. More than sixty percent of TSM could be degraded when its initial concentration were in the ranged from 5.0 to 100.0 mg·L^-1 after incubation for 7 days. The suitable degradation conditions for strain ZWS13 were under 40℃, pH 8.0, with 1% (V/V) of bacteria inoculation. More than 99% of TSM was degraded in the concentration of 50.0 mg·L^-1 at 40℃ after incubation for 10 days. Moreover, strain ZWS13 was capable of degrading nicosulfuron, pyrazosulfuron-ethyl and metsulfuron-methyl. Five degradation byproducts of TSM were identified by using HPLC-MS analysis. The degradation pathways might proceed via C-N bond cleavage of the sulfonylurea bridge, loss of -CH₃ from O-demethylation or de-esterification, and cleavage of the triazine ring. The results of present study indicated that strain ZWS13 could effectively degrade TSM and it has potential in bioremediation of soil contaminated by TSM.

Key words：biodegrdation thifensulfuron-methyl Staphylococcus sp. degradation characteristics degradation pathways