Print Email Facebook Twitter Laboratory evolution for forced glucose-xylose co-consumption enables identification of mutations that improve mixed-sugar fermentation by xylose-fermenting Saccharomyces cerevisiae Title Laboratory evolution for forced glucose-xylose co-consumption enables identification of mutations that improve mixed-sugar fermentation by xylose-fermenting Saccharomyces cerevisiae Author Papapetridis, I. (TU Delft BT/Industriele Microbiologie) Verhoeven, M.D. (TU Delft BT/Industriele Microbiologie) Wiersma, S.J. (TU Delft BT/Industriele Microbiologie) Goudriaan, M. van Maris, A.J.A. (TU Delft BT/Industriele Microbiologie) Pronk, J.T. (TU Delft BT/Biotechnologie) Department BT/Biotechnologie Date 2018 Abstract Simultaneous fermentation of glucose and xylose can contribute to improved productivity and robustness of yeast-based processes for bioethanol production from lignocellulosic hydrolysates. This study explores a novel laboratory evolution strategy for identifying mutations that contribute to simultaneous utilisation of these sugars in batch cultures of Saccharomyces cerevisiae. To force simultaneous utilisation of xylose and glucose, the genes encoding glucose-6-phosphate isomerase (PGI1) and ribulose-5-phosphate epimerase (RPE1) were deleted in a xylose-isomerase-based xylose-fermenting strain with a modified oxidative pentose-phosphate pathway. Laboratory evolution of this strain in serial batch cultures on glucose–xylose mixtures yielded mutants that rapidly co-consumed the two sugars. Whole-genome sequencing of evolved strains identified mutations in HXK2, RSP5 and GAL83, whose introduction into a non-evolved xylose-fermenting S. cerevisiae strain improved co-consumption of xylose and glucose under aerobic and anaerobic conditions. Combined deletion of HXK2 and introduction of a GAL83G673T allele yielded a strain with a 2.5-fold higher xylose and glucose co-consumption ratio than its xylose-fermenting parental strain. These two modifications decreased the time required for full sugar conversion in anaerobic bioreactor batch cultures, grown on 20 g L−1 glucose and 10 g L−1 xylose, by over 24 h. This study demonstrates that laboratory evolution and genome resequencing of microbial strains engineered for forced co-consumption is a powerful approach for studying and improving simultaneous conversion of mixed substrates. Subject biofuelsyeastindustrial biotechnologyRedox engineeringfermentationpentoses To reference this document use: http://resolver.tudelft.nl/uuid:bc4c39d6-3c8b-437a-8709-eb3b9a47170b DOI https://doi.org/10.1093/femsyr/foy056 ISSN 1567-1356 Source FEMS Yeast Research, 18 (6) Part of collection Institutional Repository Document type journal article Rights © 2018 I. Papapetridis, M.D. Verhoeven, S.J. Wiersma, M. Goudriaan, A.J.A. van Maris, J.T. Pronk Files PDF foy075.pdf 1.46 MB Close viewer /islandora/object/uuid:bc4c39d6-3c8b-437a-8709-eb3b9a47170b/datastream/OBJ/view