Biosurfactants production by solid state fermentation using Aureobasidium pullulans with sugarcane bagasse as a substrate: from biomass pretreatment to bioreactor design

Abstract

Biosurfactants are amphiphilic molecules that decrease the surface and interfacial tension by accumulating at immiscible interfaces. In addition, they are mainly synthesized by bacteria, filamentous fungi and yeast. The interest in biosurfactants in recent years is based on their low toxicity, high biodegradability, effectiveness at extreme temperatures, pH and salinity, higher foaming and possibility of production from agroindustrial byproducts. Biosurfactants obtained from yeasts have many potential applications, due to products with a Generally Regarded As Safe (GRAS) status is not toxic or pathogenic, allowing their use in different areas including food, pharmaceutical industries, cosmetics, fat degradation, detergent, secondary recovery of crude oil, pulp and paper, and oil spills managements. However, the high cost of the raw materials and the complex downstream processing are the main drawbacks to be addressed for the large scale production. Solid-State Fermentation (SSF), is a technology particularly suitable for this purpose and is commonly conducted using fungi of different genera. In this sense, studies will be carried out with Aureobasidium pullulans for the production of biosurfactant and scaled in solid state fermentation using pre-treated sugarcane bagasse. For this, a screening of hydrophilic and hydrophobic substrates will be performed to select the best inducer. Then, through the use of statistical tools, the influence of the inoculum size, particle size, pH and temperature will be evaluated in the production of biosurfactant in Erlenmeyer. After selecting the variables, the process will be optimized and the yeast growth profile will be determined in the optimized condition taking into account the yield of the biosurfactant, the pH and the biomass yield. Likewise, the biosurfactant produced will be extracted and characterized according to thin-layer chromatography, infrared spectroscopy and high-performance liquid chromatography. Subsequently, the biomolecule will be produced in a bioreactor designed for a capacity of 5 kg, where the influence of aeration and humidity in the process will be evaluated. The project intends to propose a scaling methodology for obtaining biosurfactant by Aureobasidium pullulans, for its subsequent applicability as an antimicrobial agent against phytopathogenic fungi. (AU)