Metabolic division of labor drives synergistic production of biomass, lipid and α-tocopherol in Euglena gracilis-Chlorella pyrenoidosa co-cultures.

Microalgal co-culture is a promising strategy to enhance biomass and high-value metabolite production, yet the underlying metabolic coordination remains to be fully elucidated. This study developed a synergistic co-culture system using Euglena gracilis (EG) and Chlorella pyrenoidosa (CP) to maximize biomass, lipid, and α-tocopherol yields. Under an optimized inoculation ratio of EG:CP = 3:7 in TAP medium, the co-culture achieved a biomass concentration of 1.23 g/L, lipid productivity of 163.7 mg/L/d, and α-tocopherol yield of 1976.28 μg/L, corresponding to 1.18-1.52-fold, 1.58-2.81-fold, and 2.13-9.90-fold increases relative to monoculture systems. The system produced a lipid profile enriched in polyunsaturated fatty acids (76.81%), specifically linolenic acid (C18:3, 56.47%). Notably, the logarithmic growth phase was reduced by 50% (3 days), significantly enhancing cultivation efficiency. Multi-omics analysis revealed a clear metabolic division of labor, wherein EG primarily enhanced light-harvesting capacity and antioxidative metabolite secretion, while CP intensified electron transport activity, enhanced carbon fixation capacity, and released lipid-associated metabolites, collectively driving process intensification in terms of biomass and lipid productivity. Moreover, exogenous α-lipoic acid supplementation further amplified biomass accumulation (1.34 g/L), lipid productivity (182.4 mg/L/d), and α-tocopherol production (2320.48 μg/L). These findings demonstrate that metabolic cooperation in microalgal consortia can significantly improve bioresource recovery, offering a scalable strategy for high-efficiency microalgal biorefineries.