Effect of Glutaraldehyde Multipoint Covalent Treatments on Immobilized Lipase for Hydrolysis of Acidified Oil

Immobilized lipase is a green and sustainable catalyst for hydrolysis of acidified oil. Glutaraldehyde is widely used for lipase immobilization while the appropriate strategy optimizes the catalytic performance of lipase. In this research, lipase from Candida rugosa (CRL) was immobilized on spherical silica (SiO 2 ) by glutaraldehyde multipoint covalent treatments, including covalent binding method and adsorption-crosslinking method. The enzymatic stability properties and performance in hydrolysis of refined oil and acidified oil were studied. We confirmed that the residual activity decreased while the stability increased because of the influence on secondary structure of lipase after multipoint covalent treatments. In the comparison of different immobilization strategies in multipoint covalent treatment, SiO 2 -CRL (covalent binding method) showed lower loading capacity than SiO 2 -CRL (adsorption-crosslinking method), resulting in low activity. However, SiO 2 -CRL (covalent binding method) showed better reusability and stability. Immobilized lipase via covalent binding method was more potential in the application of catalytic hydrolysis of acidified oils.