Research Information System
Journal of Microbiological Methods, vol.246, 2026 (SCI-Expanded, Scopus)
Abstract In this study, a thermostable lipase from Aspergillus oryzae (AOL) was immobilized on cotton cloth fibrils using a multilayer approach involving polyethyleneimine (PEI) and glutaraldehyde (GA). Prior to immobilization onto the support, PEI–lipase complexes were formed in solution, yielding a protein precipitation efficiency of 78% at an optimal PEI concentration of 5 mg/mL without adversely affecting enzyme activity. Cross-linking with 0.625% GA enhanced structural stability, allowing the immobilized lipase to remain firmly attached to the support after extensive washing. The immobilized biocatalyst exhibited significantly enhanced thermal stability compared to free enzyme, retaining over 70% of its initial activity after 60 min at 90 °C. Furthermore, storage studies at 4 °C demonstrated superior stability: the immobilized enzyme retained 77% of its activity after 28 days, while the free enzyme retained only 57%. In addition, the immobilized enzyme retained a high level of activity over repeated use cycles, demonstrating good reusability. Scanning electron microscopy (SEM) confirmed the successful and uniform distribution of enzyme aggregates on the cotton fibrils. Overall, this immobilization approach provides a simple and low-cost strategy to improve the thermal and storage stability of thermostable lipases, with potential applications in high temperature biocatalytic processes.