Epilactose biosynthesis using recombinant cellobiose 2-epimerase produced by Saccharomyces cerevisiae

Abstract

Cellobiose 2-epimerases are interesting enzymes that can catalyze the production of lactose-based prebiotics, namely, epilactose and lactulose, through a single substrate reaction with noteworthy yields. In this work, the GRAS yeast Saccharomyces cerevisiae was for the first time used as a host for the heterologous production of cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus. The enzyme showed an optimal temperature and an optimal pH of 80 °C and 7.5, respectively. Under these conditions, the time-course production of epilactose from lactose (50 g/L) was evaluated. The maximum yield and productivity obtained were 27\% and 9 g L1 h1, respectively. This epilactose yield represents the highest value obtained from the several approaches reported using cellobiose 2-epimerase from C. saccharolyticus. In conclusion, it was shown that the enzyme produced by S. cerevisiae is suitable for the production of epilactose-enriched prebiotic mixtures with potential applications in the food industry.