Parellel production of xylitol and ethanol

XYLITOL AND ETHANOL PRODUCTION FROM VARIOUS WINERY BY-PRODUCTS

Within the Project Biovino, the research group from the CEB-Universidade do Minho, has proposed an integrated approach for the valorization of diverse wastes resulting from winemaking processes through the biosynthesis of xylitol (37 g/L) and ethanol (50 g/L).

Using genetically modified Saccharomyces cerevisiae strains, the xylose-rich hemicellulosic fraction of hydrothermally pretreated vine shoots was converted into xylitol, and the cellulosic fraction was used to produce bioethanol. In addition, grape must, enriched in sugars, was efficiently used as a low-cost source for yeast propagation.

The production of xylitol was optimized, in a Simultaneous Saccharification and Fermentation (SSF) process configuration, by adjusting the inoculum size and enzyme loading.

Furthermore, a yeast strain displaying cellulases in the cell surface was applied for the production of bioethanol from the glucan-rich cellulosic fraction. With the addition of grape must and/or wine lees, high ethanol concentrations were reached, which are crucial for the economic feasibility of distillation.

This integrated multi-feedstock valorization provides a synergistic alternative for converting a range of winery wastes and by-products into biofuel and an added-value chemical while decreasing waste released to the environment.

Link to the journal article (open access): https://doi.org/10.1016/j.jenvman.2022.116623.

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