Abstract
d-Xylonate was produced from d-xylose using Kluyveromyces lactis strains which expressed the gene for NADP +-dependent d-xylose dehydrogenase from Trichoderma reesei (xyd1). Up to 19±2g d-xylonatel -1 was produced when K. lactis expressing xyd1 was grown on 10.5gd-galactosel -1 and 40g d-xylosel -1. Intracellular accumulation of d-xylonate (up to ~70mg [gbiomass] -1) was observed.d-Xylose was metabolised to d-xylonate, xylitol and biomass. Oxygen could be reduced to 6mmolO 2l -1h -1 without loss in titre or production rate, but metabolism of d-xylose and xylitol were more efficient when 12mmolO 2l -1h -1 were provided.d-Xylose uptake was not affected by deletion of either the d-xylose reductase (XYL1) or a putative xylitol dehydrogenase encoding gene (XYL2) in xyd1 expressing strains. K. lactis xyd1Δ XYL1 did not produce extracellular xylitol and produced more d-xylonate than the xyd1 strain containing the endogenous XYL1. K. lactis xyd1Δ. XYL2 produced high concentrations of xylitol and significantly less d-xylonate than the xyd1 strain with the endogenous XYL2.
Original language | English |
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Pages (from-to) | 383-391 |
Journal | Metabolic Engineering |
Volume | 13 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Jul 2011 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Aeration
- D-xylonic acid
- D-xylose
- D-xylose reductase
- K. lactis
- Xylitol dehydrogenase