Lignocellulosic sugar management for xylitol and ethanol fermentation with multiple cell recycling by Kluyveromyces marxianus IIPE453

Optimum utilization of fermentable sugars from lignocellulosic biomass to deliver multiple products under biorefinery concept has been reported in this work. Alcohol fermentation has been carried out with multiple cell recycling of Kluyveromyces marxianus IIPE453. The yeast utilized xylose-rich fraction from acid and steam treated biomass for cell generation and xylitol production with an average yield of 0.315 ± 0.01 g/g while the entire glucose rich saccharified fraction had been fermented to ethanol with high productivity of 0.9 ± 0.08 g/L/h. A detailed insight into its genome illustrated the strain's complete set of genes associated with sugar transport and metabolism for high-temperature fermentation. A set flocculation proteins were identified that aided in high cell recovery in successive fermentation cycles to achieve alcohols with high productivity. We have brought biomass derived sugars, yeast cell biomass generation, and ethanol and xylitol fermentation in one platform and validated the overall material balance. 2 kg sugarcane bagasse yielded 193.4 g yeast cell, and with multiple times cell recycling generated 125.56 g xylitol and 289.2 g ethanol (366 mL).