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 language | English |
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Pages (from-to) | 427-436 |
Journal | Metabolic Engineering |
Volume | 14 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Jul 2012 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Bioconversion
- D-xylonic acid
- D-xylose
- D-xylose dehydrogenase
- Saccharomyces cerevisiae