Yarrowia lipolytica as a powerful cell factory to treat saline industrial effluents: turning challenging waste into microbial oil via the carboxylate platform [DATASET]

Background: High-salinity organic residues remain largely unexploited in microbial bioprocesses due to their inhibitory effects on microbial growth. This study evaluates the feasibility of using industrial cured meat exudate, a nitrogen- and microelement-rich saline waste stream, as cultivation medium for microbial oil production by Yarrowia lipolytica. The individual effects of salinity and carbon-to-nitrogen ratio (C/N) were first investigated in defined media and subsequently validated using exudate-based media supplemented with glucose or short-chain fatty acids (SCFA). Results: In synthetic media, moderate NaCl concentrations (15–45 g/L) increased lipid accumulation by up to 40% during SCFA cultivation. Although higher salinity reduced growth and substrate uptake rates, complete SCFA consumption was achieved at NaCl concentrations up to 45 g/L within 70 h, while cells remained metabolically active even at 60 g/L NaCl. Lipid composition was primarily determined by the C/N ratio, whereas salinity exerted a secondary, condition-dependent effect. Cultivation in exudate-based medium required no external supplementation besides carbon source, reaching lipid titers of 1125 ± 29 mg/L at 10% (v/v) exudate dilution (30 g/L NaCl; C/N ≈ 100). Bioreactor cultivation under the same conditions increased productivity threefold to 25.9 mg/Lh, mainly through enhanced SCFA conversion. Lipids were dominated by C18 fatty acids, while odd-chain C17 fatty acids were enriched in exudate cultures due to precursor compounds naturally present. Conclusions: These results demonstrate the feasibility of converting saline food-processing residues into microbial oils, advancing sustainable carbon resources conversion through the valorization of underutilized industrial side streams through circular and water-efficient bioprocesses.