Intermediary Metabolite Concentrations in Xylulose- and Glucose-Fermenting
            <i>Saccharomyces cerevisiae</i>
            Cells

Senac, Thomas; Hahn‐Hägerdal, Bärbel

doi:10.1128/aem.56.1.120-126.1990

Cited by 70 publications

(30 citation statements)

References 27 publications

(28 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The maximum speci¢c growth rate on xylulose increased upon TAL overproduction, supporting the hypothesis that TAL activity limits pentose metabolism in S. cerevisiae [1,9,13]. Overproduction of TAL increased the aerobic growth on solid xylose media of a XYL1/XYL2-expressing strain [9] as measured by visual inspection of cell mass after 3 days.…”

Section: Discussionsupporting

confidence: 68%

“…Flux modelling has shown that the £ux through the reaction catalysed by RPE is very low in anaerobic xylose fermenting S. cerevisiae TMB3001 [12]. The nonoxidative PPP intermediate sedoheptulose 7-phosphate accumulates both in xylose-fermenting [1] and in xylulosefermenting [13] S. cerevisiae, suggesting insu⁄cient transaldolase activity. Overexpression of transaldolase leads to faster aerobic growth on xylose [9], but not to faster xylose fermentation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The non-oxidative pentose phosphate pathway controls the fermentation rate of xylulose but not of xylose in TMB3001

Johansson

Hahn‐Hägerdal

2002

FEMS Yeast Research

View full text Add to dashboard Cite

Saccharomyces cerevisiae is able to ferment xylose, when engineered with the enzymes xylose reductase (XYL1) and xylitol dehydrogenase (XYL2). However, xylose fermentation is one to two orders of magnitude slower than glucose fermentation. S. cerevisiae has been proposed to have an insufficient capacity of the non-oxidative pentose phosphate pathway (PPP) for rapid xylose fermentation. Strains overproducing the non-oxidative PPP enzymes ribulose 5-phosphate epimerase (EC 5.1.3.1), ribose 5-phosphate ketol isomerase (EC 5.3.1.6), transaldolase (EC 2.2.1.2) and transketolase (EC 2.2.1.1), as well as all four enzymes simultaneously, were compared with respect to xylose and xylulose fermentation with their xylose-fermenting predecessor S. cerevisiae TMB3001, expressing XYL1, XYL2 and only overexpressing XKS1 (xylulokinase). The level of overproduction in S. cerevisiae TMB3026, overproducing all four non-oxidative PPP enzymes, ranged between 4 and 23 times the level in TMB3001. Overproduction of the non-oxidative PPP enzymes did not influence the xylose fermentation rate in either batch cultures of 50 g l(-1) xylose or chemostat cultures of 20 g l(-1) glucose and 20 g l(-1) xylose. The low specific growth rate on xylose was also unaffected. The results suggest that neither of the non-oxidative PPP enzymes has any significant control of the xylose fermentation rate in S. cerevisiae TMB3001. However, the specific growth rate on xylulose increased from 0.02-0.03 for TMB3001 to 0.12 for the strain overproducing only transaldolase (TAL1) and to 0.23 for TMB3026, suggesting that overproducing all four enzymes has a synergistic effect. TMB3026 consumed xylulose about two times faster than TMB30001 in batch culture of 50 g l(-1) xylulose. The results indicate that growth on xylulose and the xylulose fermentation rate are partly controlled by the non-oxidative PPP, whereas control of the xylose fermentation rate is situated upstream of xylulokinase, in xylose transport, in xylose reductase, and/or in the xylitol dehydrogenase.

show abstract

Section: Discussionsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

The non-oxidative pentose phosphate pathway controls the fermentation rate of xylulose but not of xylose in TMB3001

Johansson

Hahn‐Hägerdal

2002

FEMS Yeast Research

View full text Add to dashboard Cite

show abstract

“…The low xylose fermentation rate in recombinant S. cerevisiae has been suggested to result from transport limitation [24] and from an insu⁄cient PPP £ux [25]. In this investigation we conclude that also the XR activity partly controls the xylose consumption rate.…”

Section: Discussionmentioning

confidence: 52%

Effect of enhanced xylose reductase activity on xylose consumption and product distribution in xylose-fermenting recombinant

Jeppsson

Träff

Johansson

et al. 2003

FEMS Yeast Research

View full text Add to dashboard Cite

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 (zwfl Delta) and TMB3261 (PGK1-XYL1, zwf1 Delta), 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.

show abstract

“…This means that in S. cerevisiae other factors like activities of other enzymes may be limiting, e.g. transaldolase, as sedoheptulose 7-phosphate has been shown to accumulate in D-xylulose fermentation [20].…”

Section: The Expression Of Xylulokinase Had No E¡ect On the Growth Ramentioning

confidence: 99%

The role of xylulokinase in Saccharomyces cerevisiae xylulose catabolism

Richard¹

2000

FEMS Microbiology Letters

View full text Add to dashboard Cite

Many yeast species have growth rates on D-xylulose of 25^130% of those on glucose, but for Saccharomyces cerevisiae this ratio is only about 6%. The xylulokinase reaction has been proposed to be the rate-limiting step in the D-xylulose fermentation with S. cerevisiae. Overexpression of xylulokinase encoding XKS1 stimulated growth on D-xylulose in a S. cerevisiae strain to about 20% of the growth rate on glucose and deletion of the gene prevented growth on D-xylulose and D-xylulose metabolism. We have partially purified the xylulokinase and characterised its kinetic properties. It is reversible and will also accept D-ribulose as a substrate. ß

show abstract

Intermediary Metabolite Concentrations in Xylulose- and Glucose-Fermenting Saccharomyces cerevisiae Cells

Cited by 70 publications

References 27 publications

The non-oxidative pentose phosphate pathway controls the fermentation rate of xylulose but not of xylose in TMB3001

The non-oxidative pentose phosphate pathway controls the fermentation rate of xylulose but not of xylose in TMB3001

Effect of enhanced xylose reductase activity on xylose consumption and product distribution in xylose-fermenting recombinant

The role of xylulokinase in Saccharomyces cerevisiae xylulose catabolism

Contact Info

Product

Resources

About