Sustainable Exploitation of Wine Lees as Yeast Extract Supplement for Application in Food Industry and Its Effect on the Growth and Fermentative Ability of Lactiplantibacillus plantarum and Saccharomyces cerevisiae

Wine lees, the residue left behind after racking or bottling of wine, are predominantly composed of dead yeast cells, ethanol, phenolic compounds, and tartrates. Yeast extract (i.e., commercial yeast extract), a highly nutritious powder derived from commercially cultivated yeast biomass, is commonly used in nutrient media as a nitrogen source. In the context of by-product valorization, wine lees could potentially be used to produce a substitute for commercial yeast extract (CYE). In our study we investigated the growth and fermentative ability of two major winemaking microorganisms, Lactiplantibacillus plantarum and Saccharomyces cerevisiae, in culture media containing a wine lees yeast extract (WLYE) and a CYE. The effects of yeast extract type, concentration, and initial cell concentration (y0) on key kinetic parameters—maximum specific growth rate (μmax), lag phase duration (λ), and maximum cell concentration (ymax)—were evaluated. For L. plantarum, the results showed that using a WLYE led to similar kinetic parameters to those obtained with a CYE, with λ being unaffected by y0 in samples containing a WLYE. For S. cerevisiae, simultaneous addition of both yeast extracts led to increased μmax values (up to 0.136 h−1) compared to individually added yeast extracts, although this negatively affected λ and ymax. Current research on wine lees is mainly focused on using them as a substrate to produce valuable metabolites through fermentation, overlooking the potential industrial applications of the nutrient-rich autolysate. The findings of this study appear promising for the holistic valorization of wine lees, contributing towards the concepts of sustainability and circular economy.