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https://hdl.handle.net/1822/2983
Título: | Effect of enhanced xylose reductase activity on xylose consumption and product distribution in xylose-fermenting recombinant Saccharomyces cerevisiae |
Autor(es): | Jeppsson, Marie Träff, Karin Johansson, Björn Hahn-Hägerdal, Bärbel Gorwa-Grauslund, Marie F. |
Palavras-chave: | Xylose reductase Xylose fermentation Saccharomyces cerevisiae Glucose-6-phosphate dehydrogenase Xylitol Redox balance |
Data: | Abr-2003 |
Editora: | Elsevier 1 |
Revista: | FEMS Yeast Research |
Citação: | "FEMS Yeast Research". ISSN 1567-1356. 3:2 (2003) 167-175. |
Resumo(s): | Recombinant Saccharomyces cerevisiae TMB3001, harboring the Pichia stipitis genes XYL1 and XYL2 (xylose reductase and xylitol dehydrogenase, respectively) and the endogenous XKS1(xylulokinase), can convert xylose to ethanol. About 30% of the consumed xylose, however, is excreted as xylitol. Enhanced ethanol yield has previously been achieved by disrupting the ZWF1 gene, encoding glucose-6- phosphate dehydrogenase, but at the expense of the xylose consumption. This is probably the result of reduced NADPH-mediated xylose reduction. In the present study, we increased the xylose reductase (XR) activity 4^19 times in both TMB3001 and the ZWF1-disrupted strain TMB3255. The xylose consumption rate increased by 70% in TMB3001 under oxygen-limited conditions. In the ZWF1-disrupted background, the increase in XR activity fully restored the xylose consumption rate. Maximal specific growth rates on glucose were lower in the ZWF1-disrupted strains, and the increased XR activity also negatively affected the growth rate in these strains. Addition of methionine resulted in 70% and 50% enhanced maximal specific growth rates for TMB3255 (zwf1v) and TMB3261 (PGK1-XYL1, zwf1v), respectively. Enhanced XR activity did not have any negative effect on the maximal specific growth rate in the control strain. Enhanced glycerol yields were observed in the high-XR-activity strains. These are suggested to result from the observed reductase activity of the purified XR for dihydroxyacetone phosphate. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/2983 |
DOI: | 10.1016/S1567-1356(02)00186-1 |
ISSN: | 1567-1356 |
Versão da editora: | http://www.elsevier.com/wps/find/journaldescription.cws_home/621190/description#description |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | DBio - Artigos/Papers |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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Jeppsson 2003b.doc | 1,45 MB | Microsoft Word | Ver/Abrir |