Immobilization of lipase from yeast Candida rugosa using modified bentonite for production of cosmetic esters

Abstract

Natural and modified clays have gained enormous interest in the enzyme immobilization field due to their ability to enhance the stability of the enzyme. The main objective of this study was to produce cosmetic esters through immobilized lipase of Candida rugosa on supporting materials, e.g., bentonite and modified bentonite. Bentonite was successfully modified by cationic surfactant cetyltrimethylammonium bromide (CTAB). The supporting materials and immobilized lipase were characterized by a Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrometer (FTIR). Determination of catalytic activity of lipase was carried out under optimal conditions of pH 7.0 and 37 °C. Free lipase (FL), immobilized lipase on bentonite (IL on B), and immobilized lipase on modified bentonite (IL on MB) had activity of 16.18 ± 0.63, 2.36 ± 0.84, and 3.74 ± 0.37 U/g, respectively. The modified bentonite had higher lipase activity than the unmodified bentonite, even though the free lipase displayed the highest activity. However, immobilized lipase on modified bentonite exhibited better performance than free lipase in terms of pH and thermal stabilities. The immobilized lipase retained the relative enzyme activity at 59%, whereas that of free lipase decreased to 43%, indicating good keeping at RT after 10 days of storage time. In addition, the immobilized lipase showed high retained activity at 80%, while the free lipase showed only 64% at 4 °C. Therefore, both free lipase and IL on MB were selected as biocatalysts in the decyl oleate (wax ester) production, and the ester product was identified at a retention time of approximately 22 min using gas chromatography-mass spectrometry (GC-MS).