Immobilization of SMG1-F278N lipase onto a novel epoxy resin: Characterization and its application in synthesis of partial glycerides

Abstract

In this study, a mutant lipase of SMG1 from Malassezia globosa (SMG1-F278N) was immobilized directly from crude fermentation broth onto a novel epoxy resin (ECR8285). The obtained immobilized SMG1-F278N was characterized and its application in synthesis of partial glycerides was evaluated. The immobilization was best achieved by an initial buffer pH of 6.0, an ionic strength of 1.5mol/L and a lipase/support ratio of 20mg/g. Several analytical approaches such as Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy showed that SMG1-F278N was successfully immobilized onto ECR8285. Besides, the properties of immobilized SMG1-F278N were investigated and it was shown that immobilized SMG1-F278N improved their performance in wider ranges of pH and temperature. It was interesting that the thermostability of immobilized SMG1-F278N was improved significantly relative to the free SMG1-F278N. Moreover, the immobilized SMG1-F278N was employed to synthesis of partial glycerides [diacylglycerol (DAG), monoacylglycerol (MAG)] via esterification of oleic acids and glycerol. High yield (79%) of partial glycerides was obtained and it was observed that high substrate molar ratio of glycerol to oleic acids contributes to the conversion of oleic acids as well as the accumulation of MAG. The immobilized SMG1-F278N was quite stable and can be reused for 7 cycles without significant loss in activity (2%). The obtained results demonstrated that the immobilized SMG1-F278N is a prospective enzyme in oils and fats industry.