Catalysis Letters, Vol.149, No.10, 2854-2863, 2019
Bioprocess Development for the Synthesis of 4-Aminophenylacetic Acid Using Nitrilase Activity of Whole Cells of Alcaligenes faecalis MTCC 12629
Nitrilases are important industrial enzymes to synthesize commercially useful acids from nitriles. In the present study, an aryl specific inducible nitrilase was produced from Alcaligenes faecalis MTCC 12629 which hydrolyzed 4-aminophenylacetonitrile to 4-aminophenylacetic acid. A bioprocess was developed to synthesize 4-aminophenylacetic acid from 4-aminophenylacetonitrile at 500ml scale under optimized reaction conditions. The maximum activity of nitrilase for biotransformation of 4-aminophenylacetonitrile was recorded in 50mM KH2PO4/K2HPO4 buffer of pH 7 at 45 degrees C. Operational stability of present enzyme was found at 45 degrees C for fed batch reaction. The bioprocess designed at 500ml scale included 17 U/ml catalyst amount, 50mM substrate addition after 30min in total five feedings for 150min at 45 degrees C. The approach of substrate feeding at lower amount resulted in accumulation of 175mM product in 500ml reaction after five feedings of substrate. The rate of product formation was found to be 2.5g/g(dcw)/h with the volumetric productivity of 26.6g/l. [GRAPHICS] .