Biological Sciences
Fermentation
Fermentation is a metabolic process that converts carbohydrates, such as sugars, into alcohol or organic acids using microorganisms like yeast or bacteria. It occurs in the absence of oxygen and is used in various applications, including the production of alcoholic beverages, bread, and certain dairy products. Fermentation is an important aspect of biotechnology and industrial microbiology.
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11 Key excerpts on "Fermentation"
- Martin B. B. Hocking(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
16 Fermentation AND OTHER MICROBIOLOGICAL PROCESSES Ale, man, ale's the stuff to drink For fellows whom it hurts to think. — Alfred E. Housman, 1896 16.1. GENERAL MICROBIOLOGICAL PRINCIPLES Strictly speaking, Fermentation is the process of anaerobic breakdown or fragmentation of organic compounds by the metabolic processes of micro-organisms. However, Fermentation processes can be considered generally to relate to the chemical changes of a substrate accomplished by selected micro-organisms or extracts of micro-organisms, to yield a useful product. This less specific definition includes microbiological processes carried out under anaer-obic (fermentative, or in the absence of air), aerobic (respiratory), and enzy-matic (via extracts) conditions. Historically, microbes of one kind or another have been used for centuries for the preparation of a variety of foods and beverages. Each Fermentation product probably arose from what was originally an accidental discovery, for example, grapes or grape juice fermenting on storage or mold growth on curds (milk solids). These were recognized as changes which increased the menu variety and the storage stability of the foodstuff, hence the appeal of the prod-ucts of these processes. It is easy to speculate, then, that each accidental dis-covery led to experiments aimed at being able to obtain the same change in the character of the food intentionally and at will. From probable early be-ginnings of this kind, yeasts have been used in the arts of wine, beer, and spirits production, as well as for the in situ production of the carbon dioxide used for leavening of bread and other bakery goods. Bacteria have been em-ployed for the preparation of a variety of cheeses, sauerkraut, and yogurt. Molds too, still have a significant utility in the preparation of certain cheeses. 501
eBook - ePubIntroductory Science of Alcoholic Beverages
Beer, Wine, and Spirits
- Masaru Kuno(Author)
- 2022(Publication Date)
- CRC Press(Publisher)
Chapter 1 FermentationDOI: 10.1201/9781003218418-1Introduction
From a biochemical standpoint, Fermentation is a metabolic process by which a microorganism converts a carbohydrate, such as a starch (a chain of sugar molecules) or a simple sugar, into an alcohol or a carboxylic acid. The two general categories of Fermentation we will be concerned with involve the conversion of sugar into ethanol and carbon dioxide (alcoholic Fermentation) or, alternatively, the conversion of these sugars into lactic acid (lactic acid Fermentation). The former is done by yeasts while the latter is conducted by bacteria such as Lactobacillus. Figure 1.1 is a picture of Lactobacillus bacteria taken using an electron microscope.Figure 1.1:Electron microscopy image of Lactobacillus.Although the actual chemistries are complicated and have many steps, Figure 1.2 conceptually summarizes the conversion of a sugar into its final alcoholic or lactic acid Fermentation products through a chemical intermediate called pyruvate. An introduction to chemical structures is provided below.Figure 1.2:Conceptual illustration of alcoholic and lactic acid Fermentation.What is the purpose of Fermentation?
Fermentation was historically used to preserve foods. Prior to the advent of refrigerators, one needed to keep meats and other foodstuffs safe to eat for prolonged periods of time. Lactic acid Fermentation made food more acidic by lowering its pH. The pH concept will be described in more detail in Chapter 4 . These acidic conditions, in turn, inhibited bacterial growth, which could spoil the food. Beyond this and without realizing it, people discovered that Fermentation could produce alcoholic beverages. This was something that people could enjoy and that ultimately became part of their daily lives. The text you are reading is therefore about such beverages and the chemistry behind their aromas and flavors as well as how they are made.Today, people recognize that Fermentation has other benefits. It helps with the digestion of certain foods. An example is soybean whose digestability improves with Fermentation. Fermentation also leads to an increase in the vitamin and overall nutrient content of foods. Flavors and aromas can likewise be enhanced.
eBook - ePub- Robert W. Hutkins(Author)
- 2018(Publication Date)
- Wiley-Blackwell(Publisher)
3 Metabolism and physiologyIf an alien visited Earth, they would take some note of humans, but probably spend most of their time trying to understand the dominant form of life on our planet – microorganisms like bacteria and viruses.Nathan Wolfe, Virologist (as quoted in National Geographic)Fermentation BASICS
For those students fresh from a general biochemistry course, they might recall that “Fermentation” was defined in their biochemistry text as something like “energy‐yielding reactions in which an organic molecule is the electron acceptor”. The definition might have also included wording about Fermentation being an anaerobic process and that the starting substrate is glucose or some other simple sugar. Thus, in the context of the lactic acid Fermentation, the pyruvic acid that is generated from glucose via the anaerobic or glycolytic pathway would serve as the electron acceptor to form lactic acid. Likewise, in the ethanolic pathway, acetaldehyde, formed by decarboxylation of pyruvate, is the electron recipient (forming ethanol). This biochemical definition is certainly true for many of the Fermentations that occur in foods. However, it is not totally adequate. For several fermented foods, important end‐products are produced via non‐fermentative pathways (as classically defined). For example, the malolactic Fermentation that is very important in wine making is really just a decarboxylation reaction that does not conform, strictly speaking, to the definition stated above. Nor does this definition apply in a range of other fermented foods, such as tempeh and koji. In these Fermentations, proteins and polysaccharides are degraded and metabolized by fungi, but without production of glycolytic end‐products. Therefore, in this book, we will not be confined to the classic, narrower definition of Fermentation. Rather, the term Fermentation will be used in a broader sense, accounting for the many metabolic and enzymatic processes that occur during the course of food Fermentations.
eBook - ePub- Peter F Stanbury, Allan Whitaker, Stephen J Hall, Peter F. Stanbury, Stephen J. Hall(Authors)
- 2016(Publication Date)
- Butterworth-Heinemann(Publisher)
The production of ethanol by the action of yeast on malt or fruit extracts has been carried out on a large scale for many years and was the first “industrial” process for the production of a microbial metabolite. Thus, industrial microbiologists have extended the term Fermentation to describe any process for the production of product by the mass culture of a microorganism. Brewing and the production of organic solvents may be described as Fermentation in both senses of the word but the description of an aerobic process as a Fermentation is obviously using the term in the broader, microbiological, context and it is in this sense that the term is used in this book.The range of Fermentation processes
There are five major groups of commercially important Fermentations:1. Those that produce microbial cells (or biomass) as the product.2. Those that produce microbial enzymes.3. Those that produce microbial metabolites.4. Those that produce recombinant products.5. Those that modify a compound that is added to the Fermentation—the transformation process.The historical development of these processes will be considered in a later section of this chapter, but it is first necessary to include a brief description of the five groups.Microbial biomass
The commercial production of microbial biomass may be divided into two major processes: the production of yeast to be used in the baking industry and the production of microbial cells to be used as human food or animal feed (single-cell protein). Bakers’ yeast has been produced on a large scale since early 1900s and yeast was produced as human food in Germany during the First World War. However, it was not until the 1960s that the production of microbial biomass as a source of food protein was explored to any great depth. As a result of this work, reviewed briefly in Chapter 2 , a few large-scale continuous processes for animal feed production were established in the 1970s. These processes were based on hydrocarbon feedstocks, which could not compete against other high protein animal feeds, resulting in their closure in the late 1980s (Sharp, 1989 ). However, the demise of the animal feed biomass Fermentation was balanced by ICI plc and Rank Hovis McDougal establishing a process for the production of fungal biomass for human food. This process was based on a more stable economic platform and has been a significant economic success (Wiebe, 2004
eBook - ePub- Davide Dionisi(Author)
- 2021(Publication Date)
- CRC Press(Publisher)
1 Introduction to Fermentation ProcessesDOI: 10.1201/9781003217275-1This chapter introduces the main concepts on Fermentation processes used in this book. Humans have been using Fermentation processes for thousands of years. There's evidence of the use of fermented alcoholic beverages in Neolithic China, and the Fermentation of milk to make yogurt was probably discovered even before then. Nowadays, industrial Fermentation processes are carried out at very large scales, for example, bioethanol is produced from starchy or sugary feedstocks using yeasts at rates of millions of cubic metres per year. Commercial-scale Fermentation processes need, therefore, to be designed and optimised taking into consideration their kinetics and stoichiometry, mass and energy balances and mass and heat transfer, which are the main focus of this book.1.1 Fermentation Processes and Microorganisms
In this book, we will use the term “Fermentation” in the broadest sense to indicate any reactions that involve the growth of living microorganisms. In a stricter sense, the term Fermentation is often used to indicate anaerobic reactions which produce a compound of interest in the liquid phase (e.g. alcoholic Fermentation), but in this book we will refer to both aerobic and anaerobic processes.Microorganisms (Figure 1.1 ) are unicellular (mostly) or multicellular organisms, in the order of micrometres in size, which grow (duplicate) on a carbon source and mineral nutrients.FIGURE 1.1Examples of microorganisms. Top left: Aspergillus niger conidia (van Leeuwen et al., 2013, Creative Commons license). Bar is 10 μm. Top right: Lactobacillus acidophilus (Bob Blaylock, CC BY-SA, https://creativecommons.org/licenses/by-sa/3.0 , https://commons.wikimedia.org/wiki/File:20101212_200110_LactobacillusAcidophilus.jpg ). Numbered ticks are 11 μm apart. Bottom left: Methanosarcina mazei (https://bacdive.dsmz.de/strain/7096 , Copyright Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH). Bottom right: Saccharomyces cerevisiae, SEM image (Mogana Das Murtey and Patchamuthu Ramasamy, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=52254246
eBook - PDF- M. Chandrasekaran(Author)
- 2012(Publication Date)
- CRC Press(Publisher)
Biotechnology can contribute to food processing through any of these components or through all of these. In all these applica-tions, Fermentation plays a crucial role in yielding products of supe-rior quality produced through environmentalfriendly technologies (Marwaha and Arora 2000). 9.2 Fundamental Principles The word “Fermentation” is derived from a Latin word meaning “to boil,” since the bubbling and foaming of early Fermentation beverages seemed closely akin to boiling. Even though Fermentation has been defined as an energy-regenerating process in which organic com-pounds act as both electron the donor and the acceptor, any bioprocess employing the action of microorganisms is generally considered to be Fermentation. The typical Fermentation process has various stages that offer opportunities for manipulating the requirements as and when needed. A judicious intervention in each of these stages is very much required for better performance of the Fermentation process meant for a specific food Fermentation. A detailed understanding of the various 206 VALORIZATION OF FOOD PROCESSING BY-PRODUCTS stages of the bioprocess can bring out the possibilities for upgradation of the process (Figure 9.1). The most important substrate utilized for Fermentation is carbohy-drate, which includes polysaccharides such as starch, cellulose, hemi-celluloses, and pectin; disaccharides such as sucrose and lactose and monosaccharides such as glucose, fructose, galactose, and xylose, besides proteins, lipids, and so on. Fermentation can also make use of natural raw materials and by-products of other industries such as corn steep liquor, molasses, starch waste, cassava waste, cellulosic waste, vegetable waste, and so on. The process may be batch, continuous, or fed-batch, aerobic or anaerobic, mono or dual, hetero or homo, and acidogenic or solventogenic in nature (Stanbury et al. 1995; Wolfe 2005).
eBook - ePubBiotechnological Progress and Beverage Consumption
Volume 19: The Science of Beverages
- Alexandru Grumezescu, Alina Maria Holban(Authors)
- 2019(Publication Date)
- Academic Press(Publisher)
Sugars are the most commonly used Fermentation substrates, and the most common products of fermentative bioprocessing of beverages are ethanol, lactic acid, propionic acid, butyric acid, or acetone (Lin et al., 2014 ; Navarrete-Bolaños et al., 2013 ; Ruijschop et al., 2008). Yeast is the most widely used microorganism that produces fermentative bioprocesses with alcohol production in beer, wine, and other alcoholic beverage technology (Marsit and Dequin, 2015 ; Varela, 2016 ; Stewart, 2016 ; Fleet, 2003 ; Swiegers and Pretorius, 2007 ; Pires et al., 2014 ; Rodda et al., 2013 ; Śliwińska et al., 2015). Fermentation is the main method of procuring energy in yeast and anaerobic bacteria, while carbohydrates are most often used in metabolism using two main metabolic pathways—Embden-Meyerhof-Parnas glycolysis and pentosophosphate pathway (Bar-Even et al., 2012 ; Kruger and von Schaewen, 2003). However, the metabolism of microorganisms is very complex, and besides the main pathways, there are many interconnected energy purchasing cycles. Even the same species of microorganisms can use one or more metabolic pathways in relation to the conditions they live in. The biotechnology of wine and beer production is based on alcoholic Fermentation, a complex process that takes place in a sequence of well-defined stages, leading to the formation of some intermediate products by the action of several enzyme systems specific to yeast Fermentation (Boulton and Quain, 2006)
eBook - ePub- Charles W. Bamforth, David J. Cook(Authors)
- 2019(Publication Date)
- Wiley-Blackwell(Publisher)
1 The Science Underpinning Food FermentationsUse the word ‘biotechnology’ nowadays and the vast majority of people will register an image of genetic alteration of organisms in the pursuit of new applications and products, many of them pharmaceutically relevant. Even the Merriam‐WebsterDictionary tells us that biotechnology is ‘biological science when applied especially in genetic engineering and recombinant DNA technology’. Fortunately the Oxford English Dictionary gives the rather more accurate definition as ‘the branch of technology concerned with modern forms of industrial production utilising living organisms, especially microorganisms, and their biological processes’.Accepting the truth of the second of these, then we can realise that biotechnology is far from being a modern concept. It harks back historically vastly longer than the traditional milepost for biotechnology, namely Watson and Crick's announcement in the Eagle pub in Cambridge (and later, more formally, in Nature) that they had found ‘the secret of life’.Eight thousand years ago our ancient forebears may have been, in their own way, no less convinced that they had hit upon the essence of existence when they made the first beers and breads. The first micro‐organism was not seen until draper Anton van Leeuwenhoek peered through his microscope in 1676 and neither were such agents firmly causally implicated in food production and spoilage until the pioneering work of Needham, Spallanzani and Pasteur and Bassi de Lodi in the eighteenth and nineteenth centuries.Without knowing the whys and wherefores, the dwellers in the Fertile Crescent were the first to make use of living organisms in Fermentation processes. They truly were the first biotechnologists. And so beer, bread, cheese, wine and most of the other foodstuffs being considered in this book come from the oldest of processes. In some cases these have not changed very much in the ensuing aeons.
eBook - ePub- Ghasem Najafpour(Author)
- 2015(Publication Date)
- Elsevier Science(Publisher)
Chapter 10Application of Fermentation Processes
Abstract
Carbohydrates obtained from grain, potato, or molasses are fermented by yeasts or bacteria to produce ethanol. Fermentation of sugar using Saccharomyces cerevisiae produces ethanol under anaerobic conditions. The batch Fermentation system is affected by high substrate and product inhibition. Glucose concentration has a major role in increasing the concentration of ethanol and cell growth rate in the Fermentation broth. Cell density, ethanol concentration, and glucose concentration are measured. Industrial grade sugars and molasses are used to produce bioethanol. Today, alcohol technologies are well developed using advance technology such as membrane bioreactors. The process is integrated Fermentation along with a pervaporation technique. Ethanol can also be produced from any organic wastes; Kluyveromyces marxianus is able to produce ethanol from cheese whey permeate. Feed stock from cellulose is hydrolyzed to fermentable sugar; then, in single or two-step Fermentation, ethanol is produced.Keywords
Analysis of mixed sugar; Biofuel; Cell dry weight; Continuous ethanol production; Ethanol Fermentation; Optical density; Refractive index; Yield of ethanolOutline10.1 Introduction 33010.2 Production of Ethanol by Fermentation 33010.3 Benefits from Bioethanol Fuel 33110.4 Stoichiometry of Biochemical Reaction 33110.5 Optical Cell Density 33210.6 Kinetics of Growth and Product Formation 33310.7 Preparation of Stock Culture 33410.8 Inoculum Preparation 33510.9 Inoculation of Seed Culture 33610.10 Analytical Method for Sugar Analysis 33710.10.1 Quantitative Analysis 33710.10.2 Analysis of Mixed Sugar by Ultraviolet 337Sample Preparation 33810.11 Analytical Method for Ethanol Analysis 33810.12 Refractive Index Determination 33810.13 Cell Dry Weight Measurements 33910.14 Yield Calculation 33910.15 Batch Fermentation Experiment 34010.16 Continuous Fermentation Experiment
eBook - PDF- Brian McNeil, Linda Harvey, Brian McNeil, Linda Harvey(Authors)
- 2008(Publication Date)
- Wiley(Publisher)
Since production of cells (or biomass) is covered under growth, here we consider other intracellular or extracellular products of Fermentation or biological activity. The energy required to drive the cell processes is the chemical energy of ATP or similar sub-stances. ATP and other energy currency compounds in the cell in most cases is provided either aerobically or anaerobically. Figure 7.9 is a schematic description of anaerobic and aerobic breakdown of carbon-and-energy substrates, and concomitant production of energy in the form of ATP and formation of various products. In aerobic cells, ATP is generated by the oxidation of substrate (usually a carbohydrate, the carbon and energy source) by molecular oxygen to CO 2 and water (oxidative phosphorylation). In anaerobic cells ATP (and other energy currency compounds) is generated by the degradation of substrate to simpler products such as ethanol, lactic acid, CO 2 and water, etc., which are excreted by the cell (substrate level phosphorylation). Biological Activity in Fermentation Systems 183 Other extracellular products include such compounds as: • exoenzymes (for breaking down substrates that cannot pass through the cell wall); • polysaccharides (for cell aggregation, avoidance of desiccation, binding metal ions, etc.); • special metabolites (e.g., antibiotics). There are substances produced in situations where the carbon substrate is in excess and other substrates, such as nitrogen or magnesium, are limiting. They include possible ‘energy storage’ compounds such as glycogen or lipids, etc., which are stored within the cell, or similar polysaccharides, etc., excreted by the cell. These products are considered by some to act as an ‘energy sink’; excess ATP is produced so as to use the limiting substrate more efficiently, and the formation of energy storage products then dissipates the chemical energy of the excess.
No longer available |Learn moreMastering Brewing Science
Quality and Production
- Matthew Farber, Roger Barth(Authors)
- 2019(Publication Date)
- Wiley(Publisher)
Mastering Brewing Science: Quality and Production, First Edition. Matthew Farber and Roger Barth. © 2019 John Wiley & Sons, Inc. Published 2019 by John Wiley & Sons, Inc. 255 After wort is made in the brewhouse, it is oxygenated and sent to a fermenter where yeast is added for Fermentation. This begins the cold side of the brew- ing process. It is often said that brewers make wort; yeast makes beer. The brewer’s job is to provide the yeast with the most favorable environment for making good beer. The process by which yeast converts the sugar in wort to ethanol and carbon dioxide is alcoholic Fermentation. Ethanol and carbon dioxide are primary flavor compounds in virtually every style of beer. Fermentation also yields many flavor‐active, minor products that can have a significant effect on the character of the beer, discussed further in Chapter 12. In this chapter, we will discuss the basic process of Fermentation, including the underlying chemistry. We will discuss Fermentation equipment and design, process monitoring and control, and best practices for yeast management in the brewery. 9.1 Fermentation PROCESS Yeast, when first pitched into wort, undergoes a classic microbiological growth curve consisting of a lag phase, an exponential phase or logarithmic (log) phase, a stationary phase, and finally, a decline phase. This growth curve Fermentation CHAPTER 9 256 Fermentation is demonstrated in Figure 9.1. In classic microbiological growth curves, these four phases represent the life cycle of microorganisms in a liquid culture. During the lag phase, the cell count does not change. During the logarithmic (log) or exponential phase, cell division occurs, resulting in a rapid increase in total cell count. During the stationary phase, the rate of cell division is the same as the rate of cell death; thus total cell count reaches a plateau. Finally, during the decline phase, cell death prevails, and the total cell count declines.
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