Detalle de: Valorization of orange peel waste through a sourdough-inspired backslopping fermentation process and assessment of the biotechnological potential of associated microorganisms

Orange peel waste (OPW), a major by-product of the citrus industry, represents a sustainable source of bioactive compounds and fermentable substrates. In this study, OPW was valorized through solid-state fermentation (SSF) using a sourdough-inspired backslopping approach and Lactiplantibacillus plantarum as starter culture. The process promoted lactic acid production, reaching up to 5–6% (d.b.), with L. plantarum dominating the bacterial population, while endogenous yeasts contributed to ethanol formation at later fermentation stages. Volatile organic compounds (VOCs) analysis revealed a selective reconfiguration of the aromatic profile, characterized by the depletion of aldehydes and terpene modulation. Notably, terpenes remained the dominant fraction throughout fermentation, indicating that the process primarily modulated their relative abundance and degree of transformation rather than inducing extensive degradation of the citrus matrix. These results highlight the key role of microbial metabolic activity in shaping aroma development. In addition, non- Saccharomyces yeasts isolated from OPW, particularly Meyerozyma guilliermondii , showed the ability to ferment relevant sugars and promote the formation of aroma-active compounds, especially esters. This highlights the potential of OPW not only as a fermentation substrate but also as a source of promising non- Saccharomyces candidates for bakery applications. Overall, this study demonstrates a sustainable strategy for OPW valorization through SSF, generating fermented ingredients and identifying microbial resources with potential technological interest for future bakery applications, thereby contributing to circular economy approaches.