来自恶臭假单胞菌的腈水解酶具有高效催化3氰基吡啶产烟酸的能力，对表达该酶的基因psn进行发酵和产酶条件优化，通过对C源、N源、磷酸盐、金属离子、温度、诱导剂浓度和诱导时间进行单因素考察，获得最适培养基条件（ g/L）：葡萄糖5、蛋白胨15、酵母粉5、（ NH4）2 SO45、K2 HPO424�5、KH2 PO45�76、MgSO40�48；最佳诱导条件：培养2�5 h后添加IPTG诱导，浓度0�2 mmol/L，诱导温度30℃。在该条件下培养，重组大肠杆菌的腈水解酶比酶活可达到45�67 U/mL，比优化前提高了2�26倍。在此基础上，于5 L发酵罐上进行C、N源的补料研究，获得最适分批补料策略，发现其腈水解酶活力可达到75�40 U/mL，是优化前的3�74倍。%Nitrilase from Pseudomonas putida exhibited high specificity toward 3-cyanopyridine and could be used for generating nicotinic acid�In order to optimize the fermentation conditions of recombination Escherichia coli for expression of psn gene, the influences of carbon source,nitrogen source,phosphorus, metal ions,temperature,IPTG concentration,time for induction of recombinant E�coli for expression of psn were optimized by single factor test�The optimum culture conditions for the production of nitrilase are as follows:glucose 5 g/L, tryptone 15 g/L, yeast extract 5 g/L, ( NH4 ) 2 SO4 5 g/L, K2 HPO4 24�5 g/L, KH2PO4 5�76 g/L,MgSO4 0�48 g/L�The optimal time point,concentration,temperature for induction with IPTG were at 2�5 h after inoculation,0�2 mmol/L and 30 ℃,respectively�The activity of nitrilase expressed in E�coli under the optimal fermentation conditions reached up to 45�67 U/mL, which was 2�26 times higher than the initial level�And the fed-batch fermentation strategy for producing nitrilase from recombination E�coli in 5 L fermentor was optimized�Under the optimized conditions of fed-batch fermentation,the specific activity reached 75�40 U/mL, which was 3�74 times higher than the initial level�
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