Novel bi-functional thermostable chimeric enzyme for feasible xylo-oligosaccharides production from agro-industrial wastes

Abstract

Arabinoxylan is a sustainable source for xylo-oligosaccharide production, as agro-industrial wastes are an abundant and the industrial interest for these prebiotics is raising due to their bioactivities for food and cosmetics. However, enzyme production costs and thermostability still represent a drawback. The main enzymes required for hydrolysis are endoxylanase and arabinofuranosidase, where GH 10 endoxylanase presents great thermostability and activity, and GH 62 enzymes are the arabinofuranosidases with the highest specificity but poor thermoresistance. In this sense, the fusion of these enzymes can generate a more stable enzyme with multiple catalytic domains in a single batch. The present study designed a bifunctional enzyme combining a GH 10 endoxylanase and a GH 62 arabinofuranosidase to enhance activity and thermostability, thus increasing the feasibility of xylo-oligosaccharides production from wastes. The chimera showed superior specificity for arabinoxylan and halotolerance than the parental enzymes and higher efficiency than commercial cocktail. Thermostability improved especially for the arabinofuranosidase module, which increased 10 °C, enabling a process at higher temperatures and lower enzyme loads, which increases efficiency and decreases contamination. Calcium and manganese enhanced thermostability and activity. Xylobiose and xylotriose yields improved by 25%, and up to 7 g/L XOS was achieved from corn hull arabinoxylan hydrolysis.