Extended fed-batch fermentation of a C5/C6 optimised yeast strain on wheat straw hydrolysate using an online refractive index sensor to measure the relative fermentation rate.

In the production of 2 generation ethanol, using Saccharomyces cerevisiae, the highest productivity obtained using C5/C6 fermenting yeast is in the co-fermentation phase, in which xylose and glucose are fermented simultaneously. Extending this phase in a fed-batch process increases the yield, rate and additionally reduces needed yeast amount for pitching. Extending this phase, as long as possible, would further enhance yield and economy of the process.

De novo biosynthesis of trans-cinnamic acid derivatives in Saccharomyces cerevisiae.

The production of natural aroma compounds is an expanding field within the branch of white biotechnology. Three aromatic compounds of interest are cinnamaldehyde, the typical cinnamon aroma that has applications in agriculture and medical sciences, as well as cinnamyl alcohol and hydrocinnamyl alcohol, which have applications in the cosmetic industry. Current production methods, which rely on extraction from plant materials or chemical synthesis, are associated with drawbacks regarding scalability, production time, and environmental impact.

Increased availability of NADH in metabolically engineered baker's yeast improves transaminase-oxidoreductase coupled asymmetric whole-cell bioconversion.

Background: Saccharomyces cerevisiae can be engineered to perform a multitude of different chemical reactions that are not programmed in its original genetic code. It has a large potential to function as whole-cell biocatalyst for one-pot multistep synthesis of various organic molecules, and it may thus serve as a powerful alternative or complement to traditional organic synthetic routes for new chemical entities (NCEs). However, although the selectivity in many cases is high, the catalytic activity is often low which results in low space-time-yields.

Exploring the potential of the glycerol-3-phosphate dehydrogenase 2 (GPD2) promoter for recombinant gene expression in .

A control point for keeping redox homeostasis in during fermentative growth is the dynamic regulation of transcription for the glycerol-3-phosphate dehydrogenase 2 () gene. In this study, the possibility to steer the activity of the promoter was investigated by placing it in strains with different ability to reoxidise NADH, and applying different environmental conditions. Flow cytometric analysis of reporter strains expressing green fluorescent protein () under the control of the promoter was used to determine the promoter activity at the single-cell level When placed in a strain background, the promoter displayed a 2-fold higher activity as compared to the strong constitutive glyceraldehyde-3-phosphate dehydrogenase ().

NADH-dependent biosensor in Saccharomyces cerevisiae: principle and validation at the single cell level.

A reporter system was constructed to measure perturbations in the NADH/NAD(+) co-factor balance in yeast, by using the green fluorescent protein gene under the control of the GPD2 promoter that is induced under conditions of excess of NADH. High fluorescence levels were obtained in a glycerol 3-phosphate dehydrogenase double deletion strain (gpd1Δgpd2Δ), which is deficient in the ability to regenerate NAD(+) via glycerol formation. The responsiveness of the reporter system to externally induced perturbations in NADH oxidation was also evaluated in the gpd1Δgpd2Δ strain background by addition of acetoin, as well as by introduction of a set of heterologous xylose reductases (XRs) having different selectivities for NADH.