Simultaneous expression of an arylacetonitrilase from Pseudomonas fluorescens and a (S)-oxynitrilase from Manihot esculenta in Pichia pastoris for the synthesis of (S)-mandelic acid

摘要: The arylacetonitrilase of Pseudomonas fluorescens EBC191 catalyzes the conversion (S)-mandelonitrile to (S)-mandelic acid and (S)-mandeloamide. This biotransformation is optimally performed under acidic pH values because rapidly decomposes neutral conditions. Therefore, gene encoding P. was integrated expressed control AOX1 promoter in methylotrophic yeast Pichia pastoris which supposed act as an acidotolerant expression system. These recombinant strains hydrolyzed (R,S)-mandelonitrile at ≥3 mandelic mandeloamide were more than previously constructed Escherichia coli whole cell catalysts synthesizing same nitrilase activity. Subsequently, simultaneously (S)-oxynitrilase Manihot esculenta each individual promoters order obtain a catalyst for synthesis from benzaldehyde cyanide. Resting cells converted conditions cyanide initially mandelonitrile immediately mandeloamide. chiral analysis products formed revealed high enantiomeric excess (S)-enantiomers.