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The fermentation processes used in alcohol production is commonly maintained in low oxygen conditions, under a blanket of carbon dioxide, while growing yeast for biomass involves aerating the broth for maximized energy production. Despite the bactericidal effects of ethanol, acidifying effects of fermentation, and low oxygen conditions of ...
The Crabtree effect is a regulatory system whereby respiration is repressed by fermentation, except in low sugar conditions. [1] When Saccharomyces cerevisiae is grown below the sugar threshold and undergoes a respiration metabolism, the fermentation pathway is still fully expressed, [ 9 ] while the respiration pathway is only expressed ...
The Crabtree effect, named after the English biochemist Herbert Grace Crabtree, [1] describes the phenomenon whereby the yeast, Saccharomyces cerevisiae, produces ethanol (alcohol) in aerobic conditions at high external glucose concentrations rather than producing biomass via the tricarboxylic acid (TCA) cycle, the usual process occurring aerobically in most yeasts e.g. Kluyveromyces spp. [2 ...
Yeast fermentation of various carbohydrate products is also used to produce the ethanol that is added to gasoline. The dominant ethanol feedstock in warmer regions is sugarcane. [8] In temperate regions, corn or sugar beets are used. [8] [9] In the United States, the main feedstock for the production of ethanol is currently corn. [8]
Liebig believed that fermentation was largely a process of decomposition as a consequence of the exposure of yeast to air and water. [4] This theory was corroborated by Liebig's observation that other decomposing matter, such as rotten plant and animal parts, interacted with sugar in a similar manner as yeast.
Humans have used fermentation in production of food for 13,000 years. [5] Humans and their livestock have microbes in the gut that carry out fermentation, releasing products used by the host for energy. [6] Fermentation is used at an industrial level to produce commodity chemicals, such as ethanol and lactate.
The natural occurrence of fermentation means it was probably first observed long ago by humans. [3] The earliest uses of the word "fermentation" in relation to winemaking was in reference to the apparent "boiling" within the must that came from the anaerobic reaction of the yeast to the sugars in the grape juice and the release of carbon dioxide.
Lager yeast normally ferments at a temperature of approximately 5 °C (41 °F) or 278 k, where Saccharomyces cerevisiae becomes dormant. A variant yeast known as Saccharomyces cerevisiae var. diastaticus is a beer spoiler which can cause secondary fermentations in packaged products. [68]