Enzymatic synthesis of S-phenyl-l-cysteine from keratin hydrolysis industries wastewater with tryptophan synthase

An economical method for production of S-phenyl-l-cysteine from keratin acid hydrolysis wastewater (KHW) containing l-serine was developed by recombinant tryptophan synthase. This study provides us with an alternative KHW utilization strategy to synthesize S-phenyl-l-cysteine. Tryptophan synthase could efficiently convert l-serine contained in KHW to S-phenyl-l-cysteine at pH 9.0, 40 °C and Trion X-100 of 0.02%. In a scale up study, l-serine conversion rate reach 97.1% with a final S-phenyl-l-cysteine concentration of 38.6 g l−1.