Study of the biochemical and kinetic properties of Candida antarctica lipase immobilized on magnetized poly(styrene-co-ethylene glycol dimethacrylate) and the development of a mathematical model for emollient ester synthesis.

The present study aimed to develop a biocatalyst through the immobilization of Candida antarctica lipase B (CALB) via physical adsorption onto magnetized poly(styrene-co-ethylene glycol dimethacrylate) (STY-EGDMA-M). Biochemical property characterization, apparent kinetic parameter determination, and thermal stability assessment were conducted using a methodology developed based on the hydrolysis of the ester methyl butyrate. The results demonstrated that immobilization expanded the enzyme's optimal pH range, with the best performance observed at pH 7.5 and 8, reaching approximately 730 U g⁻¹. Additionally, increasing the temperature to 55°C led to an enhancement in the biocatalyst's hydrolytic activity, achieving a maximum of 916.24 U g⁻¹. Kinetic parameter analysis yielded values of 321.38 ± 6.31 mM for Km and 4322.46± 75.73 U g⁻¹ for Vmax. Thermal stability tests were conducted at 55°C, revealing that 83% of the biocatalyst's initial activity was retained after 24 h of exposure. Furthermore, the biocatalyst's performance in the synthesis of emollient esters (butyl oleate, 2-ethylhexyl oleate, and octyl oleate) via solvent-free esterification was evaluated. The synthesis of emollient esters demonstrated conversions exceeding 55% for octyl oleate and 2-ethylhexyl oleate at 50 and 55°C, whereas the maximum conversion for butyl oleate was 42% at 55°C. Among the bioprocesses evaluated, the synthesis of octyl oleate was selected for kinetic modeling using the ping-pong bi-bi mechanism, with five different parameter arrangements constructed. The model with the lowest corrected Akaike information criterion (AIC_C = 129.649) was selected. The findings obtained in this work open new avenues for biotechnological applications, reinforcing the relevance of the biocatalyst as a promising tool for industrial processes and scientific research. Additionally, this study provides an alternative methodology for the biochemical characterization of immobilized lipases and employs mathematical modeling to enhance the kinetic understanding of enzymatic reactions conducted at different temperatures.