Integrating Electro-fermentation and Other Strategies to Enhance Xylitol Production From Sugarcane Hydrolysate by Saccharomyces Cerevisiae

Abstract Xylitol, a naturally occurring biomolecule, is utilized in various commercial applications, with its market expected to reach USD 1.7 billion by 2028. Large-scale commercial production typically involves rigorous chemical processes, making xylitol biosynthesis an attractive alternative. The GRAS yeast Saccharomyces cerevisiae emerges as an appealing host for this purpose due to its robustness and efficiency under industrial conditions. However, research on utilizing this yeast for xylitol production from biomass hydrolysates remains notably sparse. This study investigates various bioprocessing improvements to enhance xylitol production from sugarcane straw hydrolysate using recombinant S. cerevisiae strains FMYX and CENPX, derived from industrial and laboratory backgrounds, respectively. Strategies such as increased cell inoculum, nutrient supplementation, and electro-fermentation were employed to optimize xylose conversion in batch processes - a common industrial setup for this substrate. Adjusting the pitching rate increased xylitol productivity by up to 550%, while yeast extract and peptone (YP) supplementation resulted in a 42% increase in xylitol production by FMYX. Additionally, electro-fermentation at 1V boosted xylitol production by 37.4% for this strain. Notably, under very low cell inoculum conditions, YP supplementation led to an 870% increase in xylitol production by FMYX, matching the results achieved with a 25-fold cell inoculum or electro-fermentation. This research provides compelling evidence for a cost-effective alternative process for xylitol production, readily applicable on an industrial scale and leveraging existing industrial infrastructure. The integration of a bioelectric system in this context marks a novel approach towards sustainable xylitol biosynthesis using S. cerevisiae.