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).
- 出版日期2011-12
- 单位生物反应器工程国家重点实验室; 华东理工大学