Anaerobic biodegradation and detoxification of chloroacetamide herbicides by a novel Proteiniclasticum sediminis BAD-10T
Anaerobic biodegradation and detoxification of chloroacetamide herbicides by a novel Proteiniclasticum sediminis BAD-10T
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DOI：
10.1016/j.envres.2022.112859
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发表时间：
2022-02-10
影响因子：
8.3
通讯作者：
He, Jian
中科院分区：
文献类型：
--
作者：
Liu, Junwei;Bao, Yixuan;He, Jian
氯乙酰胺除草剂（CAAHs）是目前广泛应用于农业杂草防治的重要除草剂。然而，它们的大量应用对环境造成了严重污染，对生物具有毒性。CAAHs易进入底土、湿地沉积物、地下水等缺氧环境，主要被厌氧生物降解。目前还没有关于CAAHs纯分离物厌氧降解及厌氧代谢物毒性的研究。本研究对厌氧分离物BAD-10(T)对CAAHs的厌氧降解动力学和代谢物及其毒性进行了研究。菌株BAD-10(T)可降解甲草胺、乙草胺、异草胺、丁草胺、甲草胺和异草胺，其降解动力学符合拟一级动力学方程。n -烷氧烷基的长度对CAAHs的降解速率有显著影响，n -烷氧烷基越短，降解速率越高。在乙草胺的降解过程中，鉴定出4种代谢物：2-乙基-6-甲基-N-（乙氧基甲基）-乙酰苯胺（EMEMA）、N-（2-甲基-6-乙基苯基）-乙酰胺（MEPA）、N-2-乙基苯基乙酰胺和2-乙基-N-羧基苯胺，并提出了乙草胺的厌氧分解代谢途径。EMEMA和EMPA对斑马鱼、拟南芥和椭球小球藻的毒性明显低于乙草胺，说明菌株BAD-10(T)对乙草胺的厌氧降解是一个解毒过程。本研究揭示了CAAHs的厌氧降解动力学和分解代谢途径，并强调了沉积蛋白质体BAD-10(T)在CAAHs残留污染环境的生物修复中的潜在应用前景。
Chloroacetamide herbicides (CAAHs) are important herbicides that were widely used to control agricultural weeds. However, their mass applications have seriously contaminated environment, and they are toxic to living beings. CAAHs are easy to enter anoxic environments such as subsoil, wetland sediment, and groundwater, where CAAHs are mainly degraded by anaerobic organisms. To date, there are no research on the anaerobic degradation of CAAHs by pure isolate and toxicity of anaerobic metabolites of CAAHs. In this study, the anaerobic degradation kinetics and metabolites of CAAHs by an anaerobic isolate BAD-10(T) and the toxicity of anaerobic metabolites were studied. Isolate BAD-10(T) could degrade alachlor, acetochlor, propisochlor, butachlor, pretilachlor and metolachlor with the degradation kinetics fitting the pseudo-first-order kinetics equation. The degradation rates of CAAHs were significantly affected by the length of N-alkoxyalkyl groups, the shorter the N-alkoxyalkyl groups, the higher the degradation rates. Four metabolites 2-ethyl-6-methyl-N-(ethoxymethyl)-acetanilide (EMEMA), N-(2-methyl-6-ethylphenyl)-acetamide (MEPA), N-2-ethylphenyl acetamide and 2-ethyl -N-carboxyl aniline were identified during acetochlor degradation, and an anaerobic catabolic pathway of acetochlor was proposed. The toxicity of EMEMA and EMPA for zebrafish, Arabidopsis and Chlorella ellipsoidea were obviously lower than that of acetochlor, indicating that the anaerobic degradation of acetochlor by isolate BAD-10(T) is a detoxification process. The work reveals the anaerobic degradation kinetics and catabolic pathway of CAAHs and highlights a potential application of Proteiniclasticum sediminis BAD-10(T) for bioremediation of CAAHs residue contaminated environment.