An N₂-fixing bacterium, Ensifer meliloti CGMCC 7333, has been reported to degrade the cyano-containing neonicotinoid insecticides acetamiprid and thiacloprid using a nitrile hydratase (NHase). Here, the bioconversion of indole-3-acetonitrile (IAN) by E. meliloti, Escherichia coli overexpressing the NHase, and purified recombinant NHase was studied. E. meliloti converted IAN to the product indole-3-acetamide (IAM), and no nitrilase or amidase activities, or indole-3-acetic acid formation, were detected. Whole cells of E. meliloti converted IAN from the initial content of 6.41 to 0.06 mmol/L in 48 h. Meanwhile, forming 5.99 mmol/L IAM, the molar conversion of 94.4%. E. coli Rosetta overexpressing the NHase from E. meliloti produced 4.46 mmol/L IAM in 5 min, with a conversion rate of 91.1%. The purified NHase had a V_max for IAN conversion of 294.28 U/mg. Adding 2% and 10% (v/v) dichloromethane to 50 mmol/L sodium phosphate buffer containing 200 mg/L IAN increased the NHase activity by 26.8% and 11.5% respectively, while the addition of 20% hexane had no inhibitory effect on IAN bioconversion. E. meliloti shows high NHase activity without forming a byproduct carboxylic acid, and its tolerance of dichloromethane and hexane increases its potential for application in the green biosynthesis of high-value amide compounds.

中文翻译：

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N2固定细菌Ensifer meliloti CGMCC 7333及其表达大肠杆菌的腈水合酶对吲哚-3-乙腈的生物转化。

据报道，使用腈水合酶（NHase）固定N _2的细菌，Ensifer meliloti CGMCC 7333可以降解含氰基的新烟碱类杀虫剂乙酰胺和噻虫啉。在这里，研究了由大肠杆菌，过表达NHase的大肠杆菌对吲哚-3-乙腈（IAN）的生物转化，以及纯化的重组NHase。E. meliloti将IAN转化为产物吲哚-3-乙酰胺（IAM），未检测到腈水解酶或酰胺酶活性或吲哚-3-乙酸的形成。大肠杆菌的全细胞在48小时内将IAN从初始含量6.41转换为0.06 mmol / L。同时，形成5.99 mmol / L IAM，摩尔转化率为94.4％。大肠杆菌的Rosetta过表达来自腈水合酶E.根瘤菌产生4.46毫摩尔/ L IAM中5分钟，用91.1％的转化率。纯化的NHase的IAN转化的V _max为294.28 U / mg。向含有200 mg / L IAN的50 mmol / L磷酸钠缓冲液中添加2％和10％（v / v）二氯甲烷，可使NHase活性分别提高26.8％和11.5％，而添加20％己烷则无抑制作用。 IAN生物转化。苜蓿肠埃希氏菌显示出高的NHase活性而没有形成副产物羧酸，其对二氯甲烷和己烷的耐受性增加了其在绿色合成高价值酰胺化合物中的应用潜力。