Engineering and integration of pathways for anaerobic redox-cofactor balancing in yeast

The production of ethanol by the yeast Saccharomyces cerevisiae remains the process in industrial biotechnology with the largest product volume (ca. 100 million litres annually in 2022). Carbon losses occur due to the formation of biomass and glycerol, which can account for at least 8% of the product. Under anaerobic conditions, formation of...

Genome analysis and engineering of industrial lager brewing yeasts

Lager beer, also referred to as Pilsner, is the most popular alcoholic beverage in the world, with an annual consumption of almost 200 billion litres per year. To make lager beer, brewer’s wort is fermented with the yeast <i style="mso-bidi-font-style:normal"...

Novel genetic parts and cultivation strategies for yeast-based conversion of lignocellulosic feedstocks

The recent start-up of several full-scale ‘second generation’ ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae yeast strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. In contrast to the fermentation of hexose sugar-rich substrates, such as corn syrup or sugar...

Molecular responses of Saccharomyces cerevisiae to near-zero growth rates

Engineering precursor supply in Saccharomyces cerevisiae: New strategies for cytosolic acetyl-CoA formation

Metabolic engineering – the improvement and addition, by genetic modification, of industrially relevant properties of microorganisms with respect to catalysis, transport and regulatory functions – is a well-established method for development of more cost-effective and ‘green’ industrial processes. Rapid depletion of oil reserves and a growing...

Novel strategies for engineering redox metabolism in Saccharomyces cerevisiae

In its search to decrease the environmental impact of the production of materials and food, and for other socio-economic reasons, mankind has recently taken the first steps into a paradigm shift from a petrochemical-based society to a new, sustainable and to a significant extent bio-based society. In this new scenario, biomass derived from...

Towards fermentation of galacturonic acid-containing feedstocks with Saccharomyces cerevisiae

The ambition to reduce our current dependence on fossil transportation fuels has driven renewed interest in bioethanol. Pectin-rich feedstocks like sugar beet pulp and citrus peel, which are currently sold as cattle feed, are promising raw materials for the production of bioethanol. This thesis explores the challenges related to the fermentation...

Metabolic engineering of free-energy (ATP) conserving reactions in Saccharomyces cerevisiae

Metabolic engineering – the improvement of cellular activities by manipulation of enzymatic, transport and regulatory functions of the cell – has enabled the industrial production of a wide variety of biological molecules from renewable resources. Microbial production of fuels and chemicals thereby provides an alternative to oil-based production...

Physiology and robustness of Saccharomyces cerevisiae at near-zero specific growth rates