Immobilization of lipase on zeolite, silica, and silica-aluminas and its use in hydrolysis, esterification, and transesterification reactions

Abstract

Lipases have been immobilized on various supports to catalyze hydrolysis, esterification, and transesterification reactions efficiently. Among a broad range of materials, mesoporous silica has attracted attention thanks to its distinct characteristics and advantages, being widely used for biocatalysis applications. In this work, the lipase from Thermomyces lanuginosus (TLL) was immobilized on six different carriers: two zeolites HZSM-5 (SAR 25 and 280), mesoporous Si-MCM-41, and silica-aluminas Siral 10, 20, and 40. TLL was efficiently immobilized in Siral 20 (99.9 %) and Siral 40 (99.9 %) using 26 mg g⁻¹ of enzyme loading. Due to its more hydrophobic nature, Siral 40 was selected as the most suitable support for TLL immobilization using 5 mmol L⁻¹ of sodium phosphate buffer solution, pH 7, and rotational stirring as the optimum condition. The effect of protein concentration on the TLL immobilization was investigated, and the results adjusted well (R² > 0.99) on the Langmuir isotherm model. The Siral 40 presented a maximum adsorption capacity equal to 169 mg_protein g_support⁻¹. The heterogeneous biocatalyst (TLL-S40) was applied in biodiesel synthesis, olive oil hydrolysis, p-nitrophenyl-laurate hydrolysis, and ethyl oleate synthesis. The esterification reaction was successfully catalyzed by TLL-S40, leading to a conversion 2.6-fold higher than free TLL at 30 °C. The biocatalyst was reused for three operational cycles with a retention of 34 % of its initial conversion. The results show that Siral 40, a silica-alumina material, can potentially be employed in lipase immobilization for esterification reactions.