Quantitative Metabolomics and Its Application in Metabolic Engineering of Microbial Cell Factories Exemplified by the Baker’s Yeast

The baker’s yeast Saccharomyces cerevisiae and its beneficial properties have been recognized very early by human beings. It has been used in the making of alcoholic beverages, bread and cake long before the term biotechnology has been coined. In addition to its great importance in food industry S. cerevisiae strains are nowadays applied in many other fields for example in the production of bio-fuels from corn or sugar containing crops, in the biosorption of heavy-metals from sewage, in pharmaceuticals or in the production of precursor compounds for the synthesis of pharmaceuticals or fine chemicals. As a consequence S. cerevisiae developed to one of the most important and best investigated microbial cell factories for the industrial (white) biotechnology. Furthermore S. cerevisiae is an important model organism used to elucidate the underlying molecular mechanistic principles that are involved in complex diseases (cancer or diabetes) and metabolic disorders (Castrillo and Oliver 2005; Castrillo and Oliver 2006; Nielsen and Jewett 2008). Other important features of S. cerevisiae that led to its multifaceted applicability in industry and R&D constitute its GRAS (generally recognized as safe) status and that cells are very easy to cultivate and are readily available.