Growth-rate dependency of de novo resveratrol production in chemostat cultures of an engineered Saccharomyces cerevisiae strain

Introduction: Saccharomyces cerevisiae has become a popular host for production of non-native compounds. The metabolic pathways involved generally require a net input of energy. To maximize the ATP yield on sugar in S. cerevisiae, industrial cultivation is typically performed in aerobic, sugar-limited fed-batch reactors which, due to constraints...

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...

Reverse engineering of industrially relevant phenotypes in yeast: An integrated approach

Reverse engineering is the study of discovering the structure, function and operation of a device or system with the express aim to reconstruct its key functionalities. This principle is applied to many disciplines, from military, through computer engineering, to health, but also in metabolic engineering. In this context, reverse metabolic...

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...

Carbon dioxide fixation by Calvin-Cycle enzymes improves ethanol yield in yeast

Background Redox-cofactor balancing constrains product yields in anaerobic fermentation processes. This challenge is exemplified by the formation of glycerol as major by-product in yeast-based bioethanol production, which is a direct consequence of the need to reoxidize excess NADH and causes a loss of conversion efficiency. Enabling the use of...

De novo production of the flavonoid naringenin in engineered Saccharomyces cerevisiae

Background Flavonoids comprise a large family of secondary plant metabolic intermediates that exhibit a wide variety of antioxidant and human health-related properties. Plant production of flavonoids is limited by the low productivity and the complexity of the recovered flavonoids. Thus to overcome these limitations, metabolic engineering of...

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...

Metabolic engineering of ?-oxidation in Penicillium chrysogenum for improved semi-synthetic cephalosporin biosynthesis

Industrial production of semi-synthetic cephalosporins by Penicillium chrysogenum requires supplementation of the growth media with the side-chain precursor adipic acid. In glucose-limited chemostat cultures of P. chrysogenum, up to 88% of the consumed adipic acid was not recovered in cephalosporin-related products, but used as an additional...

Functional characterization of the oxaloacetase encoding gene and elimination of oxalate formation in the β-lactam producer Penicillium chrysogenum

Penicillium chrysogenum is widely used as an industrial antibiotic producer, in particular in the synthesis of ß-lactam antibiotics such as penicillins and cephalosporins. In industrial processes, oxalic acid formation leads to reduced product yields. Moreover, precipitation of calcium oxalate complicates product recovery. We observed oxalate...

Metabolic engineering of Saccharomyces cerevisiae for C4-dicarboxylic acid production

Biotechnological production of chemicals from renewable feedstocks offers a sustainable alternative to petrochemistry. Understanding of the biology of microorganisms and plants is increasing at an unprecedented rate and tools with which these organisms can be engineered for industrial application are becoming ever more powerful. However,...

Cytosolic NADPH balancing in Penicillium chrysogenum cultivated on mixtures of glucose and ethanol

The in vivo flux through the oxidative branch of the pentose phosphate pathway (oxPPP) in Penicillium chrysogenum was determined during growth in glucose/ethanol carbon-limited chemostat cultures, at the same growth rate. Non-stationary 13C flux analysis was used to measure the oxPPP flux. A nearly constant oxPPP flux was found for all glucose...

Comparative transcriptomics and proteomics of p-hydroxybenzoate producing Pseudomonas putida S12: Novel responses and implications for strain improvement

A transcriptomics and proteomics approach was employed to study the expression changes associated with p-hydroxybenzoate production by the engineered Pseudomonas putida strain S12pa1B1. To establish p-hydroxybenzoate production, phenylalanine-tyrosine ammonia lyase (pal/tal) was introduced to connect the tyrosine biosynthetic and p-coumarate...

Transcriptomics and quantitative physiology of ß-lactam producing Penicillium chrysogenum

With an over 1000-fold improvement in specific productivity since its discovery, penicillin is one of the very successful examples of industrial biotechnology. Although classical strain improvement programmes have been a major contributor to this success, the wish for a more rational approach towards improvements has driven the work described in...

Development and application of 13C-labeling techniques: Analyzing the pentose phosphate pathway of Penicillium chrysogenum

The 13C-labeling technique is a powerful characterization tool within the field of metabolic engineering aimed at determining intracellular steady state fluxes. The provided metabolic snapshots enable researchers to better understand and predict the phenotypic behavior of a micro-organism as a result of genetic alterations and/or different...

Engineering of redox metabolism in yeast: New strategies for improved glycerol production

Abstract not available

Engineering of Saccharomyces cerevisiae for the production of fuel ethanol from xylose

For various reasons mankind is looking for alternatives for fossil fuels. One of these alternatives is ethanol made from plant biomass. However, the plant material when broken down by hydrolysis into its sugar monomers contains a significant amount of xylose, a 5-carbon-sugar or pentose. Contrary to the sugars with 6 carbon atoms (hexoses) wild...