Synergistic enhancement of lipase catalysis via co-immobilization and chitosan-assisted crosslinking: a streamlined approach for EPA/DHA enrichment in fish oil

Efficient immobilized lipase systems are essential for industrial lipid modification, yet the combined effects of enzyme loading, support properties, and post-immobilization stabilization on catalytic performance remain underexplored. In this study, Thermomyces lanuginosus lipase (TLL), Candida antarctica lipase B (CalB), and their mixture (T + C) were respectively immobilized on two structurally distinct commercial supports (A & B)—differing in hydrophobicity, surface area, and pore size—at varied loading densities. Adsorption followed monolayer kinetics, with support B enabling higher enzyme up to 44.1 mg/g wet for T + C. Co-immobilized T + C systems exhibited enhanced catalytic activity compared to individual lipases, particularly in esterification and transesterification, benefiting from the complementary substrate specificities of TLL and CalB. Chemical crosslinking with chitosan and glutaraldehyde significantly reduced lipase desorption and improved thermal stability. The optimized system Cr-B-T + C-M (crosslinked support B-TLL + CalB with medium enzyme loading) efficiently catalyzed fish oil transesterification at 60 °C for 18 h, increasing the EPA + DHA content from 30.5% to 54.8%. All immobilized lipases retained over 80% of their initial catalytic activity after three reuses (60 °C and 18 h). These results highlight the synergistic benefits of co-immobilization and crosslinking on tailored supports, offering a versatile strategy for developing stable and efficient lipase biocatalysts for high-value lipid processing.