Assessment of lipase immobilization methods in microalgal biochar aiming its application in biodiesel synthesis

Abstract

The current project evaluates the use of Biochar obtained from microalgal biomass as a support for the immobilisation of lipases, focusing on verifying the potential of the biocatalyst in the synthesis of biodiesel. Initially, the microalgae will be grown in a modified Guillard f/2 medium in a photobioreactor of the bubble column type, and later, the biomass from the culture will be recovered by flocculation and filtration and submitted to the extraction process of the bioproducts of interest. The residual biomass intends to be transformed into biochar through the pyrolysis process, which is characterised by scanning electron microscopy (SEM) techniques, surface area analysis (BET) and infrared spectroscopy (FTIR). Afterwards, two methods of enzyme immobilisation, covalent bonding and physical adsorption, will be evaluated using different sources of lipases, such as Burkholderia cepacia (LBC), Thermomyces lanuginosus (Lipolase) and Pseudomonas fluorescens (Lipase AK). Therefore, the most efficient biocatalyst will be applied in transesterification reactions of babassu oil with ethanol to obtain ethyl esters (biodiesel). As a result of the reactions, the product will be purified and characterised according to the content of esters and viscosity. Furthermore, the operational stability of the catalytic system will be estimated using consecutive batches, in which the half-life of the biocatalyst will be calculated. This project will contribute to developing a new, viable, sustainable technology for obtaining biocatalysts that can replace conventional chemical catalysts. In addition, it will also allow the strengthening of this line of research in the Department of Chemical Engineering of the School of Engineering of Lorena of EEL/USP.