Enhanced lignin-to-lipid bioconversion via glucose-assisted co-metabolism in newly isolated bacteria

Lignin-to-lipid bioconversion is a promising approach for producing biodiesel precursors from renewable biomass, but is limited by low conversion efficiency and the scarcity of efficient microbial strains. Here, three newly isolated bacterial strains (L77, L78, and L90) were evaluated for lipid production from dealkaline lignin and lignin-derived aromatic compounds. All strains showed better growth and lipid accumulation on lignin-derived aromatics than on polymeric lignin. Glucose-assisted co-metabolism markedly improved lignin degradation and lipid biosynthesis. The maximum lipid titers reached 373.3±17.0 mg/L for L77, 527.0±11.8 mg/L for L78, and 223.3±5.4 mg/L for L90, while the highest lipid content was obtained with L78 (65.3±2.7%). Fatty acid profiling showed that C16:0 and C18:0 were the dominant components, accounting for approximately 70% of total fatty acids, indicating favorable properties for biodiesel production. These results expand the diversity of bacterial resources for lignin valorization and demonstrate the potential of newly isolated strains for sustainable microbial lipid production.