Immobilization of Amano AK lipase from Pseudomonas fluorescens on novel silk microfiber using Oxone®: Parameter optimization for enzymatic assays and use in esterification of residual palm oil

Abstract

Biodiesel has been shown to be effectively produced by immobilized enzymatic catalysts. The selection of support material is a prominent factor for obtaining an efficient lipase. Silk fibroin (SF) is a natural polymer, produced by glands of some arthropods, especially by the Bombyx mor, attracting attention for immobilization lipase attention. This paper presents a novel method to obtain silk microfibers (SMF) from Oxone® salt in water, used as support for Amano AK lipase from Pseudomonas fluorescens in biodiesel production from deodorization distillate of palm oil (DDPO). The oxone® salt in the presence of Ca2+ ions act as a mineralizing agent in the peptide bonds present in silk fibroin, altering some of its physical and chemical properties, such as zeta potential, crystallinity, micro-morphology, infrared spectroscopic profile, and showing formation or absence of SF original connections. The modified support was tested as a support alternative for the immobilization of Amano AK lipase from Pseudomonas fluorescens. Enzyme activity values indicated that lipase immobilization on SMF was efficient as a heterogeneous catalyst in the esterification of DDPO (deodorization distillate palm oil). The effect of some reaction parameters, such as catalyst concentration, molar ratio, temperature, and reaction time, was studied to optimize the conditions for maximum conversion of DDPO (40.5%).