caa a22 4500 606212027 CHVBK 20210128101041.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s10295-015-1614-9 doi (NATIONALLICENCE)springer-10.1007/s10295-015-1614-9 Deletion of hxk1 gene results in derepression of xylose utilization in Scheffersomyces stipitis [Elektronische Daten] [Mehdi Dashtban, Xin Wen, Paramjit Bajwa, Chi-Yip Ho, Hung Lee] A major problem in fermenting xylose in lignocellulosic substrates is the presence of glucose and mannose which inhibit xylose utilization. Previous studies showed that catabolite repression in some yeasts is associated with hexokinases and that deletion of one of these gene(s) could result in derepressed mutant strain(s). In this study, the hxk1 encoding hexokinase 1 in Scheffersomyces stipitis was disrupted. The ∆hxk1 SS6 strain retained the ability to utilize the main hexoses and pentoses commonly found in lignocellulosic hydrolysates as efficiently as the wild-type (WT) strain. SS6 also fermented the dominant sugars to ethanol; however, on xylose, the ∆hxk1 strain produced more xylitol and less ethanol than the WT. On mixed sugars, as expected the WT utilized glucose ahead of xylose and xylose utilization did not commence until all the glucose was consumed. In contrast, the ∆hxk1 mutant showed derepression in that it started to utilize xylose even when considerable glucose (about 1.72%, w/v) remained in the medium. Similarly, mannose did not repress xylose utilization by the ∆hxk1 mutant and xylose and mannose were simultaneously utilized. The results are of interest in efforts to engineer yeast strains capable of efficiently utilizing glucose and xylose simultaneously for lignocellulosic biomass conversion. Society for Industrial Microbiology and Biotechnology, 2015 Glucose repression nationallicence Hexokinase nationallicence Lignocellulose nationallicence Pentose-fermenting nationallicence Yeast nationallicence Dashtban Mehdi School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut Wen Xin School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut Bajwa Paramjit School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut Ho Chi-Yip Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, M5G 1X5, Toronto, ON, Canada aut Lee Hung School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut Journal of Industrial Microbiology & Biotechnology Springer Berlin Heidelberg 42/6(2015-06-01), 889-896 1367-5435 42:6<889 2015 42 10295 https://doi.org/10.1007/s10295-015-1614-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10295-015-1614-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Dashtban Mehdi School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut NATIONALLICENCE 700 1- Wen Xin School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut NATIONALLICENCE 700 1- Bajwa Paramjit School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut NATIONALLICENCE 700 1- Ho Chi-Yip Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, M5G 1X5, Toronto, ON, Canada aut NATIONALLICENCE 700 1- Lee Hung School of Environmental Sciences, University of Guelph, N1G 2W1, Guelph, ON, Canada aut NATIONALLICENCE 773 0- Journal of Industrial Microbiology & Biotechnology Springer Berlin Heidelberg 42/6(2015-06-01), 889-896 1367-5435 42:6<889 2015 42 10295