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

Background: 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 of lipase. Objective: 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). Method: The oxone® salt in the presence of Ca2+ ions acts 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. Results: 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). Conclusion: 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%).