Basic Microbiology
Philip A. Geis in Cosmetic Microbiology, 2020
Facultative anaerobes have evolved mechanisms to produce ATP (although in smaller amounts) by breaking down sugars when O2 is absent. Collectively referred to as fermentation, these mechanisms produce ATP along with a number of interesting byproducts depending on the species. Many of these byproducts are important commercially. The mechanisms of fermentation are categorized based on the major acid or alcohol byproducts that are produced. Homolactic fermentation—Produces lactic acid exclusively as a byproduct of fermentation.Heterolactic fermentation—Produces lactic acid in addition to ethanol and CO2.Alcoholic fermentation—In this mechanism, ethanol is the primary byproduct in addition to CO2.Mixed acid fermentation—Produces multiple byproducts including acetic acid, lactic acid, succinic acid, and formic acids as well as ethanol.Butanediol fermentation—In this mechanism, butanediol and ethanol are produced in large amounts along with lactic acid.
Therapeutic Properties of Fermented Foods and Beverages
Megh R. Goyal, Preeti Birwal, Durgesh Nandini Chauhan in Herbs, Spices, and Medicinal Plants for Human Gastrointestinal Disorders, 2023
There are numerous substrates and microorganisms involved in fermentation. However, the process of fermentation can be classified on the major end-product produced, such as: lactic acid fermentation, alcoholic fermentation, alkali fermentation and acetic acid fermentation. Lactic acid fermentation is carried out in the fermented milk and milk products, meat sausage, gundruk, sinki, etc., by lactic acid bacteria (LAB), where lactose is converted to lactic acid. Similarly, alcohol fermentation is carried out in cereal - based alcoholic beverages (such as: toddy and kanji) by yeast with production of ethanol from sugars. Whereas, acetic acid bacteria convert ethanol into acetic acid in certain soybean fermented products during acetic acid fermentation; and alkaline fermentation is carried out under alkaline conditions in certain soybean products.7
The Potential of Microbial Mediated Fermentation Products of Herbal Material in Anti-Aging Cosmetics
Namrita Lall in Medicinal Plants for Cosmetics, Health and Diseases, 2022
In alcohol fermentation, the glycolysis pathway produces pyruvate molecules, which are broken down into alcohol and carbon dioxide molecules by microorganisms such as yeast in the production of wine and beer. Alcoholic fermentation is divided into primary and secondary fermentation. In brief, for primary fermentation, microorganisms rapidly metabolize raw ingredients converting carbohydrates into alcohols and acids. Secondary fermentation, on the other hand, may last up to several days or weeks. In this time, the available carbohydrates become diminished and the products of fermentation, acids and alcohols accumulate. This results in microorganism death due to a significant drop in the pH and alcohol accumulation. In the instance of alcoholic beverage production, this fermentation product will be distilled to purify and concentrate the alcohol (Doelle, 1975; Anal, 2019).
A review of phage mediated antibacterial applications
Published in Alexandria Journal of Medicine, 2021
Kenneth Ssekatawa, Denis K. Byarugaba, Charles D. Kato, Eddie M. Wampande, Francis Ejobi, Robert Tweyongyere, Jesca L. Nakavuma
Lactic acid bacteria (LAB) are by far the commonest bacterial contaminants of biofuel production facilities and are believed to hamper the ethanol fermentation process hence limiting ethanol production. Ethanol fermentation presents an environment of high ethanol concentration, low pH, and low oxygen concentration thereby favoring the growth of Lactobacillus sp which are well adapted to survive under such conditions. Currently, there is no appropriate strategy to combat ethanol loss due to LAB contamination as all possible measures have limitations [91]. Contrary to that, the four experimental studies which employed phages and endolysins to control LAB growth during ethanol fermentation analyzed in this review demonstrated eye-catching bacterial growth suppression outcomes with mean efficacy of 91.6%. Most importantly, phage and endolysins mediated ethanol fermentation facility decontamination restored normal ethanol yield without losing their viability [37,92]. Because of the promising results, to eliminate the use of antibiotics for decontamination in the ethanol fermentation business, phages and endolysins should be considered as alternatives.
Fermented foods, the gut and mental health: a mechanistic overview with implications for depression and anxiety
Published in Nutritional Neuroscience, 2020
Hajara Aslam, Jessica Green, Felice N. Jacka, Fiona Collier, Michael Berk, Julie Pasco, Samantha L. Dawson
The fermentation of foods begins with the introduction of bacteria or yeast to initiate the fermentation process24 (see Fig. 1.). The microbes then transform an initial food substrate into a complex end-product that is biochemically and physiologically different to the initial substrate.25 Fermentation is a slow, anaerobic exothermic reaction whereby organic molecules are broken down into simple molecules by microbial enzymes.26 The two main types of fermenting processes are alcoholic and lactic acid fermentation.27,28 The production of lactic acid from glucose27 can be further subdivided to homolactic and heterolactic fermentation, depending on the pathways hexoses (monosaccharides with six carbon atoms) are metabolized.29 In homolactic fermentation, the pyruvate molecule is catabolized to lactic acid, and in heterolactic fermentation a mixture of other, non-lactic acid, by-products are generated.30 The microbes that undertake lactic acid fermentation are termed lactic acid bacteria (LAB). The LAB group includes genera such as Lactobacillus, Streptococcus, Enterococcus, Lactococcus, Bifidobacterium, and Leuconostoc.31 LAB are used to produce various products such as cheese, butter, yogurt, kefir, sauerkraut, pickles, fermented fruits and vegetables, soy sauce, sourdough bread, and fermented cereals.32 Alcoholic fermentation is heterolactic and involves the action of yeast, Saccharomyces, on the food substrate. In the absence of oxygen, the yeast and bacteria transform sugars into ethanol and CO2. This process is central to the manufacturing of bread, beer and wine.33
From Food for Survival to Food for Personalized Optimal Health: A Historical Perspective of How Food and Nutrition Gave Rise to Nutrigenomics
Published in Journal of the American College of Nutrition, 2019
This is a fine evolutionary biology example illustrating how two cultures separated by thousands of miles developed two distinct strategies in dealing with the poor potable water quality. To deal with the problem of lack of potable water, in the Occident, alcoholic fermentation produced alcoholic beverages safe to drink water-wise, while in the Orient, to deal with the same problem of non-potable water, a culture evolved centered around boiling water to brew tea because of the presence of a mutation in a gene that would not favor ethanol metabolism.
Related Knowledge Centers
- Biological Process
- Carbon Dioxide
- Ethanol
- Fructose
- Glucose
- Oxygen
- Sucrose
- Yeast
- Sugar
- Adenosine Triphosphate