Utilizing immobilized lipase for selective esterification in non-aqueous media: A strategy to enrich and purify conjugated linoleic acid isomers.

The specific recognition capability of Candida rugosa lipase presents a green approach for separating conjugated linoleic acid (CLA) isomers. However, its limited selectivity and poor operational stability have impeded its industrial applications. This study established a novel system based on mesoporous silica (MS)-immobilized lipase for selective esterification in a non-aqueous phase, enabling the efficient enrichment of CLA isomers. By functionalizing the MS surface and optimizing immobilization parameters, a lipase loading capacity of 89.61 ± 1.21 mg·g-1 was achieved. Subsequent optimization of the esterification conditions significantly enhanced the catalytic efficiency and selectivity of the immobilized lipase. A two-stage selective esterification process, with ethanol as the acyl acceptor, produced c9, t11-CLA with a relative purity of 87.05 % (33.02 % recovery) and t10, c12-CLA with a relative purity of 89.83 % (35.96 % recovery). This study provides a sustainable and scalable approach for the green production of high-value CLA isomers, with potential applications in functional foods and nutritional health products.