Conversion of Problematic Winery Waste into Valuable Substrate for Baker’s Yeast Production and Solid Biofuel: A Circular Economy Approach

Abstract

Research background. Wine production, regarded as a major sector in food industry, is often associated with the utilization of large amount of resources. Furthermore, wine making produces high quantity of grape pomace that is generally used for low value applications such as fertilizer and animal feed. The present research aims at exploring the possibility of improving the overall sustainability of traditional winemaking. Experimental approach. A zero waste process was developed. It includes the production of white wine and the substantial valorisation of grape pomace, which is transformed into solid biofuel, tartaric acid and concentrated grape extract as a feedstock for industrial baker’s yeast production. Results and conclusions. We estimate that a substantial renewable energy surplus of approx. 3 MJ/kg processed grapes could be achieved during this transformation. The suitability of grape extract as a potential substrate for industrial baker’s yeast production was assessed and the feasibility of its partial replacement of molasses (up to 30%) was demonstrated. Novelty and scientific contribution. We present a circular economy approach to the conversion of winery biowaste into high-value resources such as feedstock and solid biofuel.