Imobilização de celulase comercial de Trichoderma reesei em nanopartículas magnéticas mistas visando a aplicação na hidrólise do bagaço de cana-de-açúcar

Abstract

Enzyme recycling techniques have been shown to be a great attraction in lowering the production costs of second generation bioethanol. The enzymatic recycle at the end of the biomass hydrolysis process should be conducted in a manner that ensures easy recovery of the biocatalyst and the maintenance of its catalytic efficiency and operational stability. In this scenario, the application of magnetic nanoparticles (MNPs) as support for enzyme immobilization has been extensily studied becaues of the following MNPs' carachteristics: rapid enzymatic recovery by the simple application of an external magnetic field; ability of loading large amounts of protein due to their high surface area; and low fabrication costs depending on the type of nanoparticle synthesis. In this work, the use of Ni-Zn mixed magnetic nanoparticles as a support of commercial cellulase immobilization of Trichoderma reesei was evaluated. The co-precipitation method was used to synthesize nanoferrites, and the surface functionalization was conducted in the presence of 3-aminopropyltriethoxylan. Once functionalized, the mixed magnetic nanoparticles were activated with glutaraldehyde (MNP-APTES-GA), allowing the immobilization to occur through covalent attachment of the enzyme in the support. Activated nanoparticles in the presence of 25% of glutaraldehyde obtained immobilization yield of about 85%, and immobilized enzyme activity of 6.71 U/g. Pre-treated sugarcane bagasse hydrolysis assays resulted in 15.6% conversion of celulose and hemicelulose to reducing sugars. Therefore, evaluating the immobilization parameters and the enzymatic hydrolysis results, it was demonstrated that T. reesei cellulase was covalently immobilized to mixed MNPs and that the proposed biocatalyst has a promising potential for application in lignocellulosic materials hydrolysis.