Wine industry residues for biotechnological production of xylitol

Abstract

Xylitol is a naturally occurring sugar alcohol with a wide range of applications in food, pharmaceutical, and cosmetic industries. It is currently manufactured on a large scale by several companies through the chemical hydrogenation of xylose. The integration of xylose derived from waste stream feedstocks for biotechnological production of xylitol can positively contribute to achieve sustainable development. Wine producing industry annually generates large volumes of by-products and residues that contain high carbohydrate content. In this work, vine pruning residues and grape must were evaluated as feedstocks for xylitol production, using a recombinant Saccharomyces cerevisiae industrial strain [1]. Using grape must as cosubstrate for the bioconversion, the yeast strain directly converted xylose to xylitol, with efficiency similar to reactions that used pure glucose and fructose. Additionally, the capability of the engineered strain to convert D-xylose from pretreated vine pruning residue was also demonstrated. The utilization of both surplus grape must and vine pruning residues, for xylitol production in a multi-feedstock valorization approach, can address the disposal problems of wine producing industry and decrease the overall cost of the process, contributing to economic and environmental sustainability.