Upgrading Major Waste Streams Derived from the Biodiesel Industry and Olive Mills via Microbial Bioprocessing with Non-Conventional Yarrowia lipolytica Strains

This study reports the development of a bioprocess involving valorization biodiesel-derived glycerol as main carbon source for cell proliferation Yarrowia lipolytica strains and production metabolic compounds, i.e., citric acid (Cit), polyols, other bio-metabolites, substitution process tap water with olive mill wastewater (OMW) in batch fermentations, partial detoxification OMW (up to 31.1% decolorization). Increasing initial phenolics (Phen) OMW-glycerol blends led substantial Cit secretion. Maximum values, varying between 64.1–65.1 g/L, combined high yield (YCit/S = 0.682–0.690 g Cit/g sources) productivity (0.335–0.344 g/L/h) were achieved presence Phen 3 g/L. The notable accumulation endopolysaccharides (EPs) on produced biomass was determined when Y. LMBF Y-46 (51.9%) ACA-YC 5033 (61.5%) cultivated glycerol-based media. Blending various amounts negatively affected EPs polyols biosynthesis. ratio mannitol:arabitol:erythritol significantly (p < 0.05) by fermentation Erythritol major polyol absence (53.5–62.32%), while (with 1–3 g/L) promoted mannitol (54.5–76.6%). Nitrogen-limited conditions did not favor cellular lipids 16.6%). addressed sustainable management resource efficiency enabling bioconversion high-organic-load toxic waste streams into valuable products within circular bioeconomy approach.