腈水解酶活性真菌的筛选及其对氰基吡啶类化合物的转化

Screening of strains with nitrilase activity from fungi and the nitrile-hydrolyzing reactions on cyanopyridines

目的建立简便、快速的筛选方法,获得具有腈水解酶活性的真菌,并用筛选获得的菌株对氰基吡啶类化合物进行转化。方法建立了基于腈水解反应中体系pH变化为指示的微量比色筛选方法,应用筛选获得的睛水解酶活性菌对2-氰基吡啶、3-氰基吡啶、4-氰基吡啶、蓖麻碱4种化合物进行转化。结果应用微量比色筛选法从23株真菌中筛选获得一株具有腈水解酶活性的真菌As-pergillus niger 3.795;该菌株对4-氰基吡啶表现出较高活性,其全细胞转化4-氰基吡啶生成4-吡啶甲酸(异烟酸)转化率可达84%,且没有检测到副产物。

Objective To establish a rapid screening method of microorganisms with nitrilase activity from fungi and convert cyanopyridines using the strains obtained. Methods Based on the color change of an indicator due to the pH change during a nitrile-hydrolyzing reaction,a microplate colorimetric pH-responsive method was established for the screening of microorganisms with nitrilase activity. The obtained strain was used to transform 2-cyanopyridine, 3-cyanopyridine,4-cyanopyridine and ricinine. Results and Conclusions A screening among 23 strains of fungi using the microplate colorimetric method is performed, and Aspergillus niger 3.795 is found to have nitrilase activity. It shows high activity to 4-cyanopyridine and converted 4- cyanopyridine into pyridine-4-carboxylic acid（ isonicotinic acid）by whole cells with a conversion of 85%, no other byproduct is detected.