Biodegradation of Butachlor by Rhodococcus sp. Strain B1 and Purification of Its Hydrolase (ChlH) Responsible for N-Dealkylation of Chloroacetamide Herbicides

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• 作者：Hong-Ming Liu ; Li Cao ; Peng Lu ; Haiyan Ni ; Yun-Xiang Li ; Xin Yan ; Qing Hong ; Shun-Peng Li
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2012
• 出版时间：December 19, 2012
• 年：2012
• 卷：60
• 期：50
• 页码：12238-12244
• 全文大小：275K
• 年卷期：v.60,no.50(December 19, 2012)
• ISSN：1520-5118

文摘

Rhodococcus sp. strain B1 could degrade 100 mg/L butachlor within 5 days. Butachlor was first hydrolyzed by strain B1 through N-dealkylation, which resulted in the production of butoxymethanol and 2-chloro-N-(2,6-dimethylphenyl)acetamide. Butoxymethanol could be further degraded and utilized as the carbon source for the growth of strain B1, whereas 2-chloro-N-(2,6-dimethylphenyl)acetamide could not be degraded further. The hydrolase designated ChlH, responsible for the N-dealkylation of the side chain of butachlor, was purified 185.1-fold to homogeneity with 16.1% recovery. The optimal pH and temperature of ChlH were observed to be 7.0鈥?.5 and 30 掳C, respectively. This enzyme was also able to catalyze the N-dealkylation of other chloroacetamide herbicides; the catalytic efficiency followed the order alachlor > acetochlor >butachlor > pretilachlor, which indicated that the alkyl chain length influenced the N-dealkylation of the chloroacetamide herbicides. This is the first report on the biodegradation of chloroacetamide herbicides at the enzyme level.

Keywords:

butachlor; biodegradation; Rhodococcus sp. B1; protein purification; N-dealkylation