Old Yeasts

Yeast-based biotechnology traditionally regards the empirical production of fermented drinks and leavened bread, processes which surprisingly keep posing challenges and fuelling research. But yeasts nowadays also provide amenable cell factories, producing bulk and fine chemicals and molecules, and are increasingly used as tools in processes as diverse as food preservation or bioremediation. Importantly, yeasts are excellent models of cell and molecular biology for higher eukaryotes, including humans, contributing with key discoveries to understand processes and diseases. All taken, yeast-related business is worth billions, critically contributing to the economical welfare of many differently developed countries. This book provides some insights into aspects of yeast science and biotechnology less frequently addressed in the literature but nonetheless decisive to improve knowledge and, accordingly, boost up yeast-based innovation.

This volume scopes several aspects of non-conventional yeast research prepared by the leading specialists in the field. An introduction on taxonomy and systematics enhances the reader’s knowledge on yeasts beyond established ones such as Saccharomyces cerevisiae. Biotechnological approaches that involve fungal utilization of unusual substrates, production of biofuels and useful chemicals as citric acid, glutathione or erythritol are discussed. Further, strategies for metabolic engineering based on knowledge on regulation of gene expression as well as sensing and signaling pathways are presented. The book targets researchers and advanced students working in Microbiology, Microbial Biotechnology and Biochemistry.

It is well established that certain strains of yeasts are suitable for transforming grape sugars into alcohol, while other yeast strains are not suitable for grape fermentations. Recent progress has clearly demonstrated that the sensory profile of a wine is characteristic of each vine cultivated, and the quality and technological characteristics of the final product varies considerably due to the strains which have performed and/or dominated the fermentation process. Because of their technological properties, wine yeast strains differ significantly in their fermentation performance and in their contribution to the final bouquet and quality of wine, such as useful enzymatic activities and production of secondary compounds related both to wine organoleptic quality and human health. The wine industry is greatly interested in wine yeast strains with a range of specialized properties, but as the expression of these properties differs with the type and style of wine to be made, the actual trend is in the use of selected strains, which are more appropriate to optimize grape quality. Additionally, wine quality can be influenced by the potential growth and activity of undesirable yeast species, considered spoilage yeasts, which cause sluggish and stuck fermentation and detrimental taste and aroma in the wine.

This volume and its companion, Volume 350, are specifically designed to meet the needs of graduate students and postdoctoral students as well as researchers, by providing all the up-to-date methods necessary to study genes in yeast. Procedures are included that enable newcomers to set up a yeast laboratory and to master basic manipulations. Relevant background and reference information given for procedures can be used as a guide to developing protocols in a number of disciplines. Specific topics addressed in this book include cytology, biochemistry, cell fractionation, and cell biology.

The yeasts are a phylogenetically diverse group of fungi characterized by unicellular growth. Yeasts have been used for bread making and brewing beverages for millennia, and have become increasingly important in biotechnology for production of fuel alcohol, organic acids, enzymes, and various pharmacologically important chemicals. Other species are serious human, animal, and plant pathogens. Since publication of the 3rd edition of this book in 1984, numerous new species and genera have been described, many because of the application of new molecular biological methods. Molecular comparisons have now provided a phylogenetic distinction between the yeasts and other fungi, some of which have a unicellular growth phase. This book is the most definitive treatment of taxonomy and systematics of yeasts available and has been prepared by an international team of experts and is directed at taxonomists, ecologists, mycologists, microbiologists, clinicians, molecular geneticists, and biotechnologists.