文献类型：期刊文献

英文题名：A New Nitrilase-Producing Strain Named Rhodobacter sphaeroides LHS-305: Biocatalytic Characterization and Substrate Specificity

作者：Yang, Chunsheng[1];Wang, Xuedong[1];Wei, Dongzhi[1]

机构：[1]E China Univ Sci & Technol, New World Inst Biotechnol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2011

卷号：165

期号：7-8

起止页码：1556

外文期刊名：APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY

收录：;EI(收录号：20114814562468);WOS:【SCI-EXPANDED(收录号:WOS:000297222900011)】；

基金：The work is supported by National Basic Research Program (973) of China (no. 2009CB724703).

语种：英文

外文关键词：Rhodobacter sphaeroides; Nitrilase; 3-Cyanopyidine; Nicotinic acid; Biocatalyst

摘要：The characteristics of the new nitrilase-producing strain Rhodobacter sphaeroides LHS-305 were investigated. By investigating several parameters influencing nitrilase production, the specific cell activity was ultimately increased from 24.5 to 75.0 mu mol g(-1) min(-1), and hereinto, the choice of inducer proved the most important factor. The aromatic nitriles (such as 3-cyanopyridine and benzonitrile) were found to be the most favorable substrates of the nitrilase by analyzing the substrate spectrum. It was speculated that the unsaturated carbon atom attached to the cyano group was crucial for this type of nitrilase. The value of apparent K (m), substrate inhibition constant, and product inhibition constant of the nitrilase against 3-cyanopyridine were 4.5 x 10(-2), 29.2, and 8.6 x 10(-3) mol L-1, respectively. When applied in nicotinic acid preparation, the nitrilase is able to hydrolyze 200 mmol L-1 3-cyanopyridine with 93% conversion rate in 13 h by 6.1 g L-1 cells (dry cell weight).