Abstract Metsulfuron methyl is typical sulfonylurea herbicides. The degradation of metsulfuron-methyl has aroused research interests because it was mobile in natural media, and raising environmental concerns about contamination of metsulfuron-methyl to surface water. However, conventional methods cannot remove these herbicides from water efficiently. This work proposed a rapid and efficient enzymatic degradation of metsulfuron-methyl by chloroperoxidase (CPO). The effect of reaction conditions, including pH, concentration of oxidant and enzyme, and degradation time on the degradation efficiency (η) were studied and accordingly optimized. The optimum η of 93.2% for 16.7 μmol·L−1 metsulfuron-methyl was achieved after 10 min at 25 °C and weakly acidic pH. The required CPO is only 0.06 μmol·L−1. The degraded products of metsulfuron-methyl were identified by HPLC-MS. The results indicated that metsulfuron-methyl molecule was decomposed, and five smaller molecular fragments were detected. Moreover, it was found that if this enzymatic degradation was combined with following activated sludge treatment, then, this bio-cascade treatment was more effective in removal of metsulfuron-methyl in wastewater than by activated sludge alone (which was used in most municipal sewage plant). The COD removal increased from 12.09% to 74.27%. Ecotoxicity tests of 72 h EC50 for degraded solution using a green alga, Chlorella pyrenoidosa, as eco-indicator demonstrated the enzymatic degraded products had lower eco-toxicity than metsulfuron-methyl itself. Application of this bio-cascade treatment to real water sample and artificial wastewater containing metsulfuron-methyl was effectively.

中文翻译：

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甲嘧磺隆快速高效酶促降解及生物级联处理去除

摘要 甲磺隆是典型的磺酰脲类除草剂。甲嘧磺隆的降解引起了研究兴趣，因为它在自然介质中是可移动的，并且引起了对甲磺隆对地表水污染的环境问题。然而，常规方法不能有效地从水中去除这些除草剂。这项工作提出了一种通过氯过氧化物酶 (CPO) 快速有效地酶促降解甲磺隆的方法。研究了反应条件，包括pH、氧化剂和酶的浓度以及降解时间对降解效率(η)的影响并相应地进行了优化。在 25 °C 和弱酸性 pH 条件下，10 分钟后，16.7 μmol·L-1 甲嘧磺隆的最佳 η 为 93.2%。所需的CPO仅为0.06 μmol·L-1。甲嘧磺隆降解产物经HPLC-MS鉴定。结果表明，甲嘧磺隆分子被分解，检测到五个较小的分子碎片。此外，发现如果这种酶促降解与后续的活性污泥处理相结合，那么这种生物级联处理比单独使用活性污泥（大多数城市污水处理厂使用的活性污泥）更有效地去除废水中的甲嘧磺隆。 ）。COD 去除率从 12.09% 增加到 74.27%。使用绿藻蛋白核小球藻作为生态指标的降解溶液 72 小时 EC50 的生态毒性测试表明，酶促降解产物的生态毒性低于甲基嘧磺隆本身。