UWCScholar :: Browsing by Author "Maneveldt, Amber"

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Engineering robust yeast strains for the conversion of xylose derived from lignocellulosic biomass to xylitol
(University of the Western Cape, 2023) Maneveldt, Amber
To achieve a sustainable and economically viable 2G biofuels industry, biorefineries must coproduce high-value, low-volume bioproducts alongside high-volume, low-value cellulosic ethanol. This can be realised with the co-production of the low-calorie sugar substitute, xylitol which has a well-established market, as well as other chemicals. The construction of a xylitolproducing S. cerevisiae strain represents an economically feasible and environmentally friendly approach to xylitol production. Moreover, the exploitation of natural S. cerevisiae strain isolates as bioengineering hosts has the potential to be superior starting points due to their robustness towards process conditions. In this study, the xylitol-producing activities conferred to three natural isolate host strains via conventional and CRISPR-Cas9-mediated δintegration of three genes encoding a β-xylosidase, β-xylanase and xylose reductase (XR), was evaluated. The effect of over-expressed heterologous protein production on strain robustness and metabolism was also assayed. Our results revealed that the overexpressed XR failed to improve on the xylose reduction ability conferred to our strains, likely by their native GRE3 gene.