Optimization of eco-friendly synthesis of emollient esters catalyzed by immobilized lipase on Accurel MP 1000

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Abstract Efficient and reusable biocatalytic systems are essential for advancing greener routes for high-value ester synthesis. This study aimed to optimize the enzymatic synthesis of dodecyl stearate using lipase from Candida rugosa immobilized on Accurel MP 1000 (CRL-AMP), integrating enzyme immobilization and statistical modeling. The immobilization was realized by the physical adsorption method through interfacial activation of the lipase with a protein loading of 6.5 mg g −1 . A Doehlert experimental design was employed to investigate the effects of reaction time, biocatalyst loading, and agitation speed, utilizing octadecanoic acid and dodecan-1-ol in heptane (1:1). The optimized conditions (14.58% w v −1 biocatalyst, 40 min, 212.5 rpm) led to a conversion of 80.32%, with a low relative error ( < 5%). The statistical model showed strong predictive capacity (R 2 = 0.9451) and non-significant lack-of-fit ( p > 0.05), validating the experimental design. Linear, quadratic, and interaction effects were statistically significant, with agitation speed and enzyme concentration having the greatest influence on conversion. Biocatalytic evaluation revealed a concentration-dependent behavior, with particle agglomeration and diffusional limitations observed at higher CRL-AMP loadings. Reusability tests showed that CRL-AMP retained 61.7% of its initial activity after seven cycles, demonstrating satisfactory operational stability. The loss of almost 40% of the enzyme activity occurred due to water accumulation and enzyme desorption from the support. The integration of immobilization and response surface methodology enabled the development of an efficient and reusable biocatalytic system. These findings support the application of CRL-AMP in the sustainable synthesis of long-chain esters for industrial purposes.

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