Remaining acetamide in acetonitrile degradation using nitrile hydratase- and amidase-producing microorganisms
Remaining acetamide in acetonitrile degradation using nitrile hydratase- and amidase-producing microorganisms
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DOI：
10.1007/s00253-006-0738-2
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发表时间：
2007-03
影响因子：
5
通讯作者：
Erina Kohyama;Mizuho Dohi;Akihiro Yoshimura;Toyokazu Yoshida;T. Nagasawa
中科院分区：
文献类型：
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作者：
Erina Kohyama;Mizuho Dohi;Akihiro Yoshimura;Toyokazu Yoshida;T. Nagasawa
涉及腈水合酶和酰胺酶生产微生物的串联转化过程具有用于处理含乙腈废物的潜力。在该方法中，与由腈水合酶催化的乙腈水合步骤相比，由酰胺酶催化的乙酰胺水解步骤非常慢，并且少量乙酰胺残留在所得溶液中。本研究旨在提高乙酰胺水解步骤的效率。一种产酰胺酶的微生物，红球菌属（Rhodococcussp.）S13-4，新获得的，其使用能够快速降解乙酰胺。虽然仍然检测到残留的乙酰胺，但在使用Rhodococcussp.的乙酰胺水解反应之后，通过添加阳离子/阴离子混合离子交换树脂或氢氧化钙成功地减少了残留的乙酰胺。S13-4细胞。这一结果意味着乙酰胺水解和乙酰胺形成处于平衡状态。红球菌Rhodococcussp. S13-4细胞在高浓度乙酸铵下产生乙酰胺。从红球菌属Rhodococcussp. S13-4显示了乙酰胺形成活性（比活性为30.6U/mg蛋白）。这表明酰胺酶催化的酰胺形成可能导致乙腈转化过程中残留乙酰胺。
The tandem conversion process involving nitrile hydratase- and amidase-producing microorganisms has potential for use in the treatment of acetonitrile-containing wastes. In that process, the acetamide hydrolysis step catalyzed by amidase is very slow compared with the acetonitrile hydration step catalyzed by nitrile hydratase, and a small amount of acetamide remains in the resulting solution. This study aimed to improve the efficiency of the acetamide hydrolysis step. An amidase-producing microorganism,Rhodococcussp. S13-4, was newly obtained, whose use enabled rapid acetamide degradation. Though residual acetamide was still detected, it was successfully reduced by the addition of cation/anion mixed ion exchange resin or calcium hydroxide after the acetamide hydrolysis reaction usingRhodococcussp. S13-4 cells. This result implies that acetamide hydrolysis and acetamide formation are in equilibrium. The incubation ofRhodococcussp. S13-4 cells with high concentrations of ammonium acetate produced acetamide. The purified amidase fromRhodococcussp. S13-4 revealed the acetamide formation activity (specific activity of 30.6 U/mg protein). This suggests that the amidase-catalyzed amide formation may cause the remaining of acetamide in the acetonitrile conversion process.