| CPC C12N 15/52 (2013.01) [C12N 1/16 (2013.01); C12N 9/92 (2013.01); C12P 7/10 (2013.01); C12N 1/185 (2021.05); C12P 2203/00 (2013.01); C12R 2001/865 (2021.05); C12Y 503/01005 (2013.01)] | 7 Claims |
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1. A method for fermenting pentose sugar comprising culturing a microorganism in a culture medium comprising pentose sugar(s) under conditions in which the pentose sugar(s) can be metabolized, wherein the microorganism has been transformed with a single expression construct(s) for
i) the overexpression of native genes encoding xylulose kinase (XKS1), transaldolase (TAL1), transketolase 1 (TKL1) and transketolase 2 (TKL2) and
ii) the expression of a functional heterologous gene encoding a xylose isomerase (XI), wherein the xylose isomerase (XI) gene is encoded by a nucleic acid sequence having at least 95% sequence identify to SEQ ID No 21,
wherein the xylulose kinase (XKS1) is encoded by a nucleic acid sequence having at least 95% sequence identity to SEQ ID No 74, the transaldolase (TAL1) is encoded by a nucleic acid sequence having at least 95% sequence identity to SEQ ID No 77, the transketolase 1 (TKL1) is encoded by a nucleic acid sequence having at least 95% sequence identity to SEQ ID No 80 and the transketolase 2 (TKL2) is encoded by a nucleic acid sequence having at least 95% sequence identity to SEQ ID No 83,
wherein the xylose isomerase (XI) gene is under the control of a constitutive promoter of Saccharomyces cerevisiae;
wherein the pentose sugar is xylose; and
wherein the microorganism is a yeast of the species Saccharomyces cerevisiae.
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