From Waste to Resource: The Development of a Sustainable Bacterial Culture Medium from Wine Lees and Toxicity Evaluation in the Zebrafish Model

Wine lees (WL) are one of the main byproducts generated during winemaking and are usually disposed of in landfills or incorporated into the soil as an organic amendment; nevertheless, these practices can have negative environmental impacts. Reusing agro-industrial byproducts is a key step toward more sustainable production cycles, and WL represent a promising alternative for formulating culture media for the production of lactic acid bacteria (LAB) biomass, microorganisms widely used in the food and wine industries. In this work, we aim to evaluate the ecotoxicity of WL using a bioassay with zebrafish (Danio rerio) embryos and to analyze their potential as a source of nitrogen and growth factors for the production of UNQLp 11 Lactiplantibacillus plantarum strain biomass in whey permeate. Trials conducted with zebrafish showed that embryos exposed to WL exhibited increased mortality in a concentration-dependent response and the appearance of sublethal effects, such as alterations in embryonic development. Regarding WL biotechnological application, the results obtained confirm that the growth of Lpb. plantarum depends largely on the composition of the culture medium. Whey permeate media (WP) without supplementation showed nutritional limitations, reflected in lower cell counts. While supplementation with WL significantly improved bacterial growth, in some cases reaching values comparable to those obtained with MRS. The results demonstrated that WL can act as an efficient nutrient source, with the potential to replace commercial yeast extract in Lpb. plantarum culture media.