Screening of perhydrolases to optimize glucose oxidase-perhydrolase-in situ chemical oxidation cascade reaction system and its application in melanin decolorization.

Abstract A novel glucose oxidase (GOD)-perhydrolase-in situ chemical oxidation (ISCO) cascade reaction system was designed, optimized, and verified the operation feasibility in this research. Among the determined four perhydrolases, acyltransferase from Mycobacterium smegmatis (MsAcT) displayed the highest specific activity for perhydrolysis reaction (76.4 U/mg) and the lowest Km value to hydrogen peroxide (13.9 mmol/L). GOD-MsAcT cascade reaction system also displayed high catalytic efficiency. Under the optimal parameters (50:1 activity unit ratio of GOD to MsAcT, pH 8.0, 50 mmol/L of β-D-glucose, and 15 mmol/L of glyceryl triacetate), the melanin decolorization rate using GOD-MsAcT-ISCO cascade reaction system reached 86.8%. Kinetics of GOD-MsAcT-ISCO cascade reaction system for melanin decolorization fitted the kinetic model of Boltzmann sigmoid. As a substitutive skin whitening technology, GOD-MsAcT-ISCO cascade reaction system displayed an excellent application prospect.