Metabolic engineering of Saccharomyces cerevisiae for bioconversion of d-xylose to d-xylonate

Mervi Toivari, Yvonne Nygård, Esa Pekka Kumpula, Maija Leena Vehkomäki, Mojca Benčina, Mari Valkonen, Hannu Maaheimo, Martina Andberg, Anu Koivula, Laura Ruohonen, Merja Penttilä, Marilyn G. Wiebe

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45 Citations (Scopus)

Abstract

An NAD +-dependent d-xylose dehydrogenase, XylB, from Caulobacter crescentus was expressed in Saccharomyces cerevisiae, resulting in production of 17±2g d-xylonate l -1 at 0.23gl -1h -1 from 23g d-xylose l -1 (with glucose and ethanol as co-substrates). d-Xylonate titre and production rate were increased and xylitol production decreased, compared to strains expressing genes encoding T. reesei or pig liver NADP +-dependent d-xylose dehydrogenases. d-Xylonate accumulated intracellularly to ~70mgg -1; xylitol to ~18mgg -1. The aldose reductase encoding gene GRE3 was deleted to reduce xylitol production. Cells expressing d-xylonolactone lactonase xylC from C. crescentus with xylB initially produced more extracellular d-xylonate than cells lacking xylC at both pH 5.5 and pH 3, and sustained higher production at pH 3. Cell vitality and viability decreased during d-xylonate production at pH 3.0. An industrial S. cerevisiae strain expressing xylB efficiently produced 43g d-xylonate l -1 from 49g d-xylose l -1.

Original languageEnglish
Pages (from-to)427-436
JournalMetabolic Engineering
Volume14
Issue number4
DOIs
Publication statusPublished - 1 Jul 2012
MoE publication typeA1 Journal article-refereed

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Keywords

  • Bioconversion
  • D-xylonic acid
  • D-xylose
  • D-xylose dehydrogenase
  • Saccharomyces cerevisiae

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