标题：Rapid and efficient enzymatic degradation of metsulfuron-methyl and its removal by bio-cascade treatment
作者：Lu, Jing; Wang, Fengjiao; Li, Xuelian; Song, Yichao; Xiao, Ling; Wang, Yuebo; Jiang, Yucheng
作者机构：[Lu, Jing; Wang, Fengjiao; Li, Xuelian; Song, Yichao; Xiao, Ling; Jiang, Yucheng] Shaanxi Normal Univ, Sch Chem & Chem Engn, Key Lab Macromol Sci Shaa 更多
通讯作者：Wang, YB;Jiang, YC
通讯作者地址：[Wang, YB]Shandong Univ Technol, Sch Chem & Chem Engn, 266 Xincun West Rd, Zibo 255000, Shandong, Peoples R China;[Jiang, YC]Shaanxi Normal Univ, Sch 更多
关键词：Bio-cascade treatment; eco-toxicity evaluation; enzymatic degradation;; metsulfuron methyl; process optimization; products determination
摘要：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 (eta) were studied and accordingly optimized. The optimum eta of 93.2% for 16.7 mu mol center dot L-1 metsulfuron-methyl was achieved after 10 min at 25 degrees C and weakly acidic pH. The required CPO is only 0.06 mu mol center dot 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.