Download or read book Improving Fructose Utilization in Wine Yeast Using Adaptive Evolution written by Tommaso Liccioli and published by . This book was released on 2010 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Saccharomyces cerevisiae is the most important micro organism involved in the production of fermented alcoholic beverages such as wine. Despite its fermentative capacity and production of desirable metabolites, grape juice represents a hostile environment for yeasts. Sometimes, adverse conditions reduce yeast biomass formation or catabolic capacity, which may lead to stuck or sluggish fermentation. These phenomena represent one of the most common problems during the wine production process and mean that winery throughput is reduced and residual sugar adds unwanted sweetness in dry wine styles while offering substrates for microbial spoilage. The scientific community has always been alert to the problems linked with fermentation, considering the vital role of this organism during the production process. For this reason research has focussed on developing a range of techniques for strain improvement. With the emergence of modern molecular genetics, the new methodologies of hybridization and genetic engineering have been used to isolate and create new yeast strains. However, their application in wine microbiology is not without complications, as genetically modified yeasts are not universally favoured for commercial use in the food industry. A recent development is the notion of using the natural capacity of a population of single celled organisms to adapt themselves to an environment imposing a specific stress. The technique is termed "adaptive evolution" or "directed evolution". In principle the process is simple: when a species is constricted to live and replicate under stressful conditions for many generations, some cells will present adaptive characteristics: i.e. "adaptive mutations" and outgrow the starting population. A key benefit of this technique is that it does not rely on direct manipulation at the level of DNA, and can be used to reproduce the stress conditions found in nature or in fermentation tanks. However, adaptive evolution is a technology that needs to be more fully explored and developed for its possible use in improving wine yeast strains. A possible improvement for wine yeasts targets their sugar catabolic capacity. The different affinity of S. cerevisiae for glucose and fructose is thought to be a cause of stuck or sluggish fermentations in the winemaking process. The possibility of obtaining a strain with improved fructose utilization using adaptive evolution is therefore the topic of this investigation. This thesis describes work that can be divided into four sections. The first part is the identification of a candidate strain from a selection of commercially available wine yeasts. The second part is aimed at evolving the candidate strain under a selective pressure. The third validates new methods for assessing the populations of candidate evolved yeast in order to isolate clones that can metabolize fructose more efficiently compared to the parental strain. The last part is focussed on a deeper investigation and comparison of a number of potentially evolved candidates with the parent. To identify a candidate strain for use in the adaptive evolution process, it was necessary to compare fermentative performances of commercially available strains. Fermentations for 20 strains were conducted in synthetic media, containing fructose as sole sugar or else an equivalent concentration of glucose and fructose. Particular attention was focussed on the rate of fructose consumption relative to glucose, and thus it was necessary to identify a methodology that was independent of sugar concentration, overall fermentation rate or duration. As such the value of the area under the fermentation curves determined by the composite trapezoid rule was utilised to compare glucose and fructose utilisation and hence define the fructophilicity of each strain screened. This approach allowed the most suitable candidate strain to be chosen for the application of adaptive evolution. Accordingly, strain AWRI 796 was cultured under fermentative conditions that elicited an appropriate selective pressure over some 350 generations. Samples of the population were collected every 50 generations for characterization of individual clones. The next stage of the project focussed on the identification of clones which showed improved fructose utilization compared to the parental strain. To define fermentative performance of a high number of isolates from the adaptive evolution experiment, it was necessary to develop screening methodologies. For this purpose fermentations in microtiter plates and automated colorimetric assays for determination of residual sugar were adopted. From 378 clones examined, four were identified to be faster consumers of fructose relative to the parent. Patterns of glucose utilisation in these clones were unchanged. The last stage of the study validated the improved fermentation ability of these novel phenotypes under winemaking related conditions in fermentations of 20 kg of red grapes. In these experiments two isolates again showed a significant reduction in the time required for completion of the fermentation. The results validate the approach used and the selective pressures applied as a means introducing specific improvements into wine yeast strains.

Download or read book Yeast Biotechnology 2 0 written by Ronnie G. Willaert and published by MDPI. This book was released on 2019-01-10 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Yeast Biotechnology 2.0" that was published in Fermentation

Download or read book Improving Wine Yeast for Fructose and Nitrogen Utilization written by Lesetja Moraba Legodi and published by . This book was released on 2008 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Novel Wine Yeast Strains Using Adaptive Evolution written by Colin Michael McBryde and published by . This book was released on 2006 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Yeasts in the Production of Wine written by Patrizia Romano and published by Springer Nature. This book was released on 2019-09-16 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Yeast Sugar Metabolism written by Friedrich K. Zimmermann and published by CRC Press. This book was released on 1997-03-10 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yeast Sugar Metabolism looks at the biomechanics, genetics, biotechnology and applications of yeast sugar. The yeast Saccharomyces cereisiae has played a central role in the evolution of microbiology biochemistry and genetics, in addition to its use of a technical microbe for the production of alcoholic beverages and leavening of dough.

Download or read book Functional and Comparative Genomics of Saccharomyces and non Saccharomyces Yeasts Potential for Industrial and Food Biotechnology written by Isabel Sá-Correia and published by Frontiers Media SA. This book was released on 2020-02-25 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1996, when the first Saccharomyces cerevisiae genome sequence was released, a wealth of genomic data has been made available for numerous S. cerevisiae strains, its close relatives, and non-conventional yeast species isolates of diverse origins. Several annotated genomes of interspecific hybrids, both within the Saccharomyces clade and outside, are now also available. This genomic information, together with functional genomics and genome engineering tools, is providing a holistic assessment of the complex cellular responses to environmental challenges, elucidating the processes underlying evolution, speciation, hybridization, domestication, and uncovering crucial aspects of yeasts´ physiological genomics to guide their biotechnological exploitation. S. cerevisiae has been used for millennia in the production of food and beverages and research over the last century and a half has generated a great deal of knowledge of this species. Despite all this, S. cerevisiae is not the best for all uses and many non-conventional yeast species have highly desirable traits that S. cerevisiae does not have. These include tolerance to different stresses (e.g. acetic acid tolerance in Zygosaccharomyces bailii, osmotolerance in Z. rouxii, and thermotolerance in Kluyveromyces marxianus and Ogataea (Hansenula) polymorpha), the capacity of assimilation of diverse carbon sources (e.g. high native capacity to metabolyze xylose and potential for the valorization of agroforest residues by Scheffersomyces (Pichia) stipites), as well as, high protein secretion, fermentation efficiency and production of desirable flavors, capacity to favor respiration over fermentation, high lipid biosynthesis and accumulation, and efficient production of chemicals other than ethanol amongst many. Several non-Saccharomyces species have already been developed as eukaryotic hosts and cell factories. Others are highly relevant as food spoilers or for desirable flavor producers. Therefore, non-conventional yeasts are now attracting increasing attention with their diversity and complexity being tackled by basic research for biotechnological applications. The interest in the exploitation of non-conventional yeasts is very high and a number of tools, such as cloning vectors, promoters, terminators, and efficient genome editing tools, have been developed to facilitate their genetic engineering. Functional and Comparative Genomics of non-conventional yeasts is elucidating the evolution of genome functions and metabolic and ecological diversity, relating their physiology to genomic features and opening the door to the application of metabolic engineering and synthetic biology to yeasts of biotechnological potential. We are entering the era of the non-conventional yeasts, increasing the exploitation of yeast biodiversity and metabolic capabilities in science and industry. In this collection the industrial properties of S. cerevisiae, in particular uses, are explored along with its closely related species and interspecific hybrids. This is followed by comparisons between S. cerevisiae and non-conventional yeasts in specific applications and then the properties of various non-conventional yeasts and their hybrids.

Download or read book Non conventional Yeasts from Basic Research to Application written by Andriy Sibirny and published by Springer. This book was released on 2019-08-12 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Advances in Grape and Wine Biotechnology written by Antonio Morata and published by BoD – Books on Demand. This book was released on 2019-09-04 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Grape and Wine Biotechnology is a collection of fifteen chapters that addresses different issues related to the technological and biotechnological management of vineyards and winemaking. It focuses on recent advances in the field of viticulture with interesting topics such as the development of a microvine model for research purposes, the mechanisms of cultivar adaptation and evolution in a climate change scenario, and the consequences of vine water deficit on yield components. Other topics include the metabolic profiling of different Saccharomyces and non-Saccharomyces yeast species and their contribution in modulating the sensory quality of wines produced in warm regions, the use of new natural and sustainable fining agents, and available physical methods to reduce alcohol content. This volume will be of great interest to researchers and vine or wine professionals.

Download or read book Wine Fermentation written by Harald Claus and published by MDPI. This book was released on 2019-03-28 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wineries are facing new challenges due to actual market demands for the creation of products exhibiting more particular flavors. In addition, climate change has lead to the requirement for grape varieties with specific features, such as convenient maturation times, enhanced tolerance towards dryness, osmotic stress, and resistance against plant-pathogens. The next generation of yeast starter cultures should produce wines with an appealing sensory profile and less alcohol. This Special Issue comprises actual studies addressing some of the problems and solutions for the environmental, technical, and consumer challenges of wine making today: Development of sophisticated mass spectroscopic methods enable the identification of the major metabolite spectrum of grapes/wine and deliver detailed insights in terroir and yeast-specific traits;Knowledge of the origin and reactions of reductive sulphur compounds facilitates the avoidance of unpleasant wine odors;Innovative physical–chemical treatments support effective and sustainable color extraction from red grape varieties;Enological enzymes from yeasts used directly or in the form of starter cultures are promising tools to increase the juice yields, color intensity, and aroma of wine;Natural and artificial Saccharomyces hybrids as well as collections of adapted wild isolates from various ecological niches will extend winemakers repertoire, allowing individual fermentations;Exact process control of wine fermentations by convenient computer programs will guarantee consistently high product quality.

Download or read book Yeast Stress Responses written by Stefan Hohmann and published by Springer Science & Business Media. This book was released on 2007-10-23 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: Every cell has developed mechanisms to respond to changes in its environment and to adapt its growth and metabolism to unfavorable conditions. The unicellular eukaryote yeast has long proven as a particularly useful model system for the analysis of cellular stress responses, and the completion of the yeast genome sequence has only added to its power This volume comprehensively reviews both the basic features of the yeast genral stress response and the specific adapations to different stress types (nutrient depletion, osmotic and heat shock as well as salt and oxidative stress). It includes the latest findings in the field and discusses the implications for the analysis of stress response mechanisms in higher eukaryotes as well.

Download or read book Concise Encyclopedia of Science and Technology of Wine written by V. K. Joshi and published by CRC Press. This book was released on 2021-07-21 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: When asking the question what is wine? there are various ways to answer. Wine is extolled as a food, a social lubricant, an antimicrobial and antioxidant, and a product of immense economic significance. But there is more to it than that. When did humans first start producing wine and what are its different varieties? Are wines nutritious or have any therapeutic values—do they have any role in health or are they simply intoxicating beverages? How are their qualities determined or marketed and how are these associated with tourism? Concise Encyclopedia of Science and Technology of Wine attempts to answer all these questions and more. This book reveals state-of-the-art technology of winemaking, describing various wine regions of the world and different cultivars used in winemaking. It examines microbiology, biochemistry, and engineering in the context of wine production. The sensory qualities of wine and brandy are explored, and the composition, nutritive and therapeutic values, and toxicity are summarized. Selected references at the end of each chapter provide ample opportunity for additional study. Key Features: Elaborates on the recent trends of control and modeling of wine and the techniques used in the production of different wines and brandies Focuses on the application of biotechnology, especially genetic engineering of yeast, bioreactor technological concepts, enzymology, microbiology, killer yeast, stuck and sluggish fermentation, etc. Illustrates the biochemical basis of wine production including malolactic fermentation Examines marketing, tourism, and the present status of the wine industry Concise Encyclopedia of Science and Technology of Wine contains the most comprehensive, yet still succinct, collection of information on the science and technology of winemaking. With 45 chapters contributed by leading experts in their fields, it is an indispensable treatise offering extensive details of the processes of winemaking. The book is an incomparable resource for oenologists, food scientists, biotechnologists, postharvest technologists, biochemists, fermentation technologists, nutritionists, chemical engineers, microbiologists, toxicologists, organic chemists, and the undergraduate and postgraduate students of these disciplines.

Download or read book Grapes and Wine written by Antonio Morata and published by BoD – Books on Demand. This book was released on 2022-06-15 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grape and Wine is a collective book composed of 18 chapters that address different issues related to the technological and biotechnological management of vineyards and winemaking. It focuses on recent advances, hot topics and recurrent problems in the wine industry and aims to be helpful for the wine sector. Topics covered include pest control, pesticide management, the use of innovative technologies and biotechnologies such as non-thermal processes, gene editing and use of non-Saccharomyces, the management of instabilities such as protein haze and off-flavors such as light struck or TCAs, the use of big data technologies, and many other key concepts that make this book a powerful reference in grape and wine production. The chapters have been written by experts from universities and research centers of 9 countries, thus representing knowledge, research and know-how of many regions worldwide.

Download or read book Metabolic and molecular adaptation of wine yeast at low temperature fermentation written by María López Malo and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biology of Microorganisms on Grapes in Must and in Wine written by Helmut König and published by Springer. This book was released on 2017-11-01 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of the book begins with the description of the diversity of wine-related microorganisms, followed by an outline of their primary and energy metabolism. Subsequently, important aspects of the secondary metabolism are dealt with, since these activities have an impact on wine quality and off-flavour formation. Then chapters about stimulating and inhibitory growth factors follow. This knowledge is helpful for the growth management of different microbial species. The next chapters focus on the application of the consolidated findings of molecular biology and regulation the functioning of regulatory cellular networks, leading to a better understanding of the phenotypic behaviour of the microbes in general and especially of the starter cultures as well as of stimulatory and inhibitory cell-cell interactions during wine making. In the last part of the book, a compilation of modern methods complete the understanding of microbial processes during the conversion of must to wine.This broad range of topics about the biology of the microbes involved in the vinification process could be provided in one book only because of the input of many experts from different wine-growing countries.

Download or read book Microbial Biotechnology Providing Bio based Components for the Food Industry written by Laurent Dufossé and published by Frontiers Media SA. This book was released on 2020-01-17 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbiota of Grapes Positive and Negative Role on Wine Quality written by Giuseppe Spano and published by Frontiers Media SA. This book was released on 2017-03-28 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: During spontaneous food/beverage fermentations, the microbiota associated with the raw material has a considerable importance: this microbial consortium evolves in reason of the nutrient content and of the physical, chemical, and biological determinants present in the food matrix, shaping fermentation dynamics with significant impacts on the ‘qualities’ of final productions. The selection from the indigenous micro-biodiversity of ‘virtuous’ ecotypes that coupled pro-technological and biotechnological aptitudes provide the basis for the formulation of ‘tailored’ starter cultures. In the fermenting food and beverage arena, the wine sector is generally characterized by the generation of a high added value. Together with a pronounced seasonality, this feature strongly contributes to the selection of a large group of starter cultures. In the last years, several studies contributed to describe the complexity of grapevine-associated microbiota using both culture-dependent and culture-independent approaches. The grape-associated microbial communities continuously change during the wine-making process, with different dominances that correspond to the main biotechnological steps that take place in wine. In order to simplify, following a time trend, four major dominances can be mainly considered: non-Saccharomyces, Saccharomyces, lactic acid bacteria (LAB), and spoilage microbes. The first two dominances come in succession during the alcoholic fermentation: the impact of Saccharomyces (that are responsible of key enological step of ethanol production) can be complemented/integrated by the contributions of compatible non-Saccharomyces strains. Lactic acid bacteria constitute the malolactic consortium responsible of malolactic fermentation, a microbial bioconversion often desired in wine (especially in red wine production). Finally, the fourth dominance, the undesired microbiota, represents a panel of microorganisms that, coupling spoilage potential to the resistance to the harsh conditions typical of wine environment, can cause important economic losses. In each of these four dominances a complex microbial biodiversity has been described. The studies on the enological significance of the micro-biodiversity connected with each of the four dominances highlighted the presence of a dichotomy: in each consortia there are species/strains that, in reason of their metabolisms, are able to improve wine ‘qualities’ (resource of interest in starter cultures design), and species/strains that with their metabolism are responsible of depreciation of wine. Articles describing new oenological impacts of yeasts and bacteria belonging to the four main categories above mentioned (non-Saccharomyces, Saccharomycetes, lactic acid bacteria, and spoilage microbes) are welcome. Moreover, in this Research Topic, we encourage mini-review submissions on topics of immediate interest in wine microbiology that link microbial biodiversity with positive/negative effects in wine.