Biochemical Characterization of Candida rugosa Lipase Immobilized on Green Synthesized Gold Nanoparticles

Introduction: Lipases are one of the most essential enzymes in biological systems and industries. The use of free lipase is not cost-effective because of its low half-life. Enzyme immobilization on different supports leads to enhanced stability, reusability, ease of product separation, and low cost. Lipases have been immobilized on various organic and inorganic supports, but recently, nanoparticles have been used because of their high surface-to-volume unit. The present study aims to green synthesize gold nanoparticles, covalently immobilize lipase, and compare the biochemical characteristics of free and immobilized enzymes. Materials and Methods: After synthesis of the nanoparticles and immobilization of lipase, nanoparticles and enzyme immobilization were characterized and confirmed by SEM microscopy, Raman spectroscopy, and DLS. The biochemical characteristics, such as optimal pH and temperature, thermal stability, and storage stability of free and immobilized enzymes, were then determined. Results: The SEM results showed that the diameter of the synthesized nanoparticles was less than 50 nm. The Raman diagram of immobilized lipase showed two characterized peaks at 1468.44 cm-1 and 1639.61 cm-1 wavelength, confirming the immobilization process. Toward the free enzyme, the optimum pH of the immobilized enzyme shifted 0.5 units to the acidic range, whereas the optimum temperature did not change. Immobilized lipase showed higher thermal stability at 55 and 60 °C. Storage stability of the immobilized enzyme increased compared with the free enzyme. The immobilized enzyme could be used 10 times under optimum conditions. Conclusions: It appears that the immobilized lipase has improved characteristics for application in different industries.

Biochemical Characterization of Candida rugosa Lipase Immobilized on Green Synthesized Gold Nanoparticles Keywords:

Nanoparticle , Gold , Candida rugosa lipase , Covalent immobilization