Feasibility assessment of sugarcane-to-ethanol vinasse treated by oxidative processes as fungal culture medium

Abstract

The production of sugar-based ethanol from sugarcane generates vinasse as one of the by-products, which is characterized by its high organic load, sulfate and potassium and low nitrogen concentration. The chemical characterization of vinasse prevents it from being an efficient microbial culture medium for fungi, which, for instance, could produce high-value metabolites. There are, however, various techniques for pretreatment of the vinasse in order to reduce its microbial toxicity, such as those based on advanced oxidative processes, chemical precipitation and even some based on white-rot fungi, producers of laccase and manganese peroxidase. Mucor circinelloides is a fungal strain of industrial interest, due to its robustness and growth capacity in culture media with significant concentrations of inhibitory compounds. The zygomycete M. circinelloides is also capable of producing high concentrations of intracellular lipids, enzymes of industrial interest, such as lipases, high-value compounds, such as surfactants and pigments, and also fungal biomass with high protein content. The undergraduate researcher to be inserted to this project will be in charge of developing pre-treatment techniques of the sugarcane-to-ethanol vinasse using oxidative pathways, such as ozonization and chemical precipitation in order to adapt the vinasse as a growth medium for the fungus M. circinelloides. The researcher also will be responsible for performing chemical and physico-chemical characterization of vinasse, both in nature and post-treatment, aiming at the degradation of recalcitrant organic matter, inhibitory compounds (e.g.: phenol) and naturally inhibitory properties of vinasse, such as high concentration of minerals, which increase osmotic pressure in microorganisms. (AU)