Overexpression of NADH-dependent fumarate reductase improves d-xylose fermentation in recombinant Saccharomyces cerevisiae

Laura Salusjärvi, Sanna Kaunisto, Sami Holmström, Maija-Leena Vehkomäki, Kari Koivuranta, Juha-Pekka Pitkänen, Laura Ruohonen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

10 Citations (Scopus)

Abstract

Deviation from optimal levels and ratios of redox cofactors NAD(H) and NADP(H) is common when microbes are metabolically engineered. The resulting redox imbalance often reduces the rate of substrate utilization as well as biomass and product formation. An example is the metabolism of d-xylose by recombinant Saccharomyces cerevisiae strains expressing xylose reductase and xylitol dehydrogenase encoding genes from Scheffersomyces stipitis. This pathway requires both NADPH and NAD+. The effect of overexpressing the glycosomal NADH-dependent fumarate reductase (FRD) of Trypanosoma brucei in d-xylose-utilizing S. cerevisiae alone and together with an endogenous, cytosol directed NADH-kinase (POS5?17) was studied as one possible solution to overcome this imbalance. Expression of FRD and FRD + POS5?17 resulted in 60 and 23 % increase in ethanol yield, respectively, on d-xylose under anaerobic conditions. At the same time, xylitol yield decreased in the FRD strain suggesting an improvement in redox balance. We show that fumarate reductase of T. brucei can provide an important source of NAD+ in yeast under anaerobic conditions, and can be useful for metabolic engineering strategies where the redox cofactors need to be balanced. The effects of FRD and NADH-kinase on aerobic and anaerobic d-xylose and d-glucose metabolism are discussed.
Original languageEnglish
Pages (from-to)1383-1392
Number of pages9
JournalJournal of industrial microbiology and biotechnology
Volume40
Issue number12
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

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Keywords

  • Fumarate reductase
  • NADH-kinase
  • Saccharomyces cerevisiae
  • NADH
  • NADPH
  • d-Xylose
  • metabolic engineering
  • d-Xylose fermentation

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