Enzyme immobilization is a powerful strategy to enhance stability, reusability, and industrial applicability of biocatalysts. In the present study, lipase from Aspergillus carbonarius NRL369 was immobilized on polyethylene terephthalate (PET) beads and evaluated for its efficiency in transesterification reactions. This study introduces a new approach by demonstrating that transesterification can proceed efficiently under atypical conditions for lipase, including a heterogeneous reaction medium, and in exploring the enzyme's potential for ester synthesis. The influence of reaction time, acyl acceptor type and concentration, solvent medium, and operational stability was investigated. Iso-amyl alcohol and ethyl acetate emerged as the most effective acyl acceptors at 0.8 mmol/L, whereas methanol completely inhibited catalytic activity. Optimal activity was achieved after 90 minutes, particularly in hydrophobic solvents such as hexane and diethyl ether, while dimethylformamide and tert-butanol led to enzyme deactivation. The immobilized lipase demonstrated strong reusability, maintaining 85–89% of its initial activity after five cycles. These results highlight the potential of A. carbonarius NRL369 lipase as a high-performance and efficient biocatalyst for industrial transesterification processes, including biodiesel production and functional ester synthesis, where stability and solvent tolerance are critical for sustainable and scalable biocatalysis. The aim of this study was to optimize key reaction parameters affecting lipase-catalyzed transesterification using polyethylene terephthalate (PET) as an immobilization support.
Panajotova et al. (Mon,) studied this question.