Novel Propagation Strategy of Saccharomyces cerevisiae for Enhanced Xylose Metabolism during Fermentation on Softwood Hydrolysate

An economically viable production of second-generation bioethanol by recombinant xylose-fermenting Saccharomyces cerevisiae requires higher xylose fermentation rates and improved glucose–xylose co-consumption. Moreover, S. recognises as a non-fermentable rather than fermentable carbon source, which might partly explain why is not fermented into ethanol efficiently glucose. This study proposes propagating on sources to enhance metabolism during fermentation. When compared yeast grown sucrose, cells propagated mix glycerol in shake flasks showed up 50% utilisation rate (in defined medium) double maximum rate, together with an C5/C6 co-consumption (on industrial softwood hydrolysate). Based these results, automated propagation protocol was developed, using fed-batch approach the respiratory quotient guide glycerol-containing feed. successfully produced 71.29 ± 0.91 g/L average productivity 1.03 0.05 g/L/h. These empirical findings provide basis for design simple, yet effective strategy be used industry increased efficiency.