Activated Carbon Functionalization for Lipase Immobilization: Characterization, Hydrolytic Activity, and Ethyl Lactate Synthesis

This study aimed to evaluate the effect of different surface modifications of activated carbon: genipin (GAC), iminodiacetic acid associated with metal particles (MAC), and the combination of genipin with metal particles (GMAC). For the immobilization of two lipases (porcine pancreatic lipase - PPL and Candida rugosa lipase - CRL). In addition, the applicability of the resulting biocatalysts was investigated using ethyl lactate synthesis as a model esterification reaction (40 °C/4 h, with a 1:3 molar ratio of lactic acid to ethanol). All adsorbents showed immobilization yield higher than 87%, with metalized activated carbons exhibiting the highest hydrolytic activities for both immobilized enzymes (48.1 U for PPL and 51.6 U for CRL). The immobilized derivatives achieved ethyl lactate conversions above 90% for both enzymes, with PPL GMAC reaching 94.2%, comparable to the native enzyme (94.9%). Moreover, the derivatives-maintained ester conversions above 80% after five consecutive reaction cycles under organic reaction conditions (GMAC 85.8% for PPL; GMAC 88.1% for CRL), indicating that the immobilization strategy effectively reduced enzyme desorption while preserving catalytic activity. Therefore, the synthesized derivatives demonstrated potential as reusable biocatalysts for the production of industrially important ester compounds, contributing to the development of more sustainable biotechnological processes.