Cloud point extraction of phenolics from sugarcane juice improves its usability as a carbon source in bioprocessing of lipids from Rhodosporidium kratochvilovae MTCC247

Abstract

Sugarcane juice (ScJ) is a natural and renewable reservoir of sucrose, which makes it a sustainable carbon source for fermentative production of microbial products. This study encompasses the production of an oleaginous yeast (OY), Rhodosporidium kratochvilovae MTCC247 on ScJ-based nutrient medium and optimization of the fermentation process. Initially, ScJ was clarified by cloud point extraction (CPE) of polyphenols using Box Behnken Design resulting in 90.88 % reduction in polyphenols. After individual optimization of fermentation parameters such as initial pH, incubation temperature, agitation speed, aeration ratio and inoculum size, suitability of clarified ScJ as a sole carbon source was established by incorporating it in a fermentation medium to produce OY. Using a rotatable central composite design, optimal concentrations of medium components were determined to achieve maximum biomass production of 23.13 ± 1.72 g/L and maximum lipid production of 7.15 ± 0.377 g/L. The dynamics of fatty acid pool in OY were studied throughout fermentation. For efficient lipid extraction, a combination of mechanical method (high-speed homogenization) and chemical methods (acid treatment) could recover 93.14 ± 12 % lipids. Thus, this study illustrates the potential of clarified ScJ as a sustainable carbon source in bioprocessing of lipids from OY.