In Situ CALB Immobilization in Xerogel and Sonogel Employing TMOS as Silica Precursor and Polyethylene Glycol as Additive

The immobilization of enzymes, especially lipases, presents a significant challenge in contemporary biotechnology due to their wide-ranging application in industrial processes. Given the array of available techniques for enzyme immobilization, this study aimed to immobilize Candida antarctica B (CALB) lipase within silica xerogel and sonogel matrices obtained through the sol–gel technique. Polyethylene glycol (PEG) was incorporated as an additive, with tetramethylorthosilicate (TMOS) serving as the silica precursor. This study assessed the operational stability, storage stability, and thermal properties of the resulting supports. Results revealed that both sonogel and xerogel supports, supplemented with PEG, maintained storage stability above 50% throughout a 365-day period. Moreover, operational stability tests demonstrated that the xerogel support could be reused up to 21 times, while the sonogel support exhibited 10 reuses. Thermal analysis further highlighted a reduction in the deactivation constant and an elongation of the half-life time for both supports. These observations suggest that the supports effectively shield the enzyme from thermal inactivation. Overall, these findings underscore the potential utility of PEG-enhanced sonogel and xerogel supports in various industrial enzyme applications, providing valuable insights into their operational, storage, and thermal stability.