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Ethanol fermentation, also called alcoholic fermentation, is a biological process which converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as by-products.
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.
The process may be likened to how yeast ferments sugars to produce ethanol for wine, beer, or fuel, but the organisms that carry out the ABE fermentation are strictly anaerobic (obligate anaerobes). The ABE fermentation produces solvents in a ratio of 3 parts acetone, 6 parts butanol to 1 part ethanol.
In biochemistry, fermentation theory refers to the historical study of models of natural fermentation processes, especially alcoholic and lactic acid fermentation. Notable contributors to the theory include Justus Von Liebig and Louis Pasteur , the latter of whom developed a purely microbial basis for the fermentation process based on his ...
Ethanol is a neutral molecule and the pH of a solution of ethanol in water is nearly 7.00. Ethanol can be quantitatively converted to its conjugate base, the ethoxide ion (CH 3 CH 2 O −), by reaction with an alkali metal such as sodium: [79] 2 CH 3 CH 2 OH + 2 Na → 2 CH 3 CH 2 ONa + H 2. or a very strong base such as sodium hydride: CH 3 CH ...
Grapes being trodden to extract the juice and made into wine in storage jars. Tomb of Nakht, 18th dynasty, Thebes, Ancient Egypt. Sourdough starter. In food processing, fermentation is the conversion of carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—without an oxidizing agent being used in the reaction.
Industrial fermentation is the intentional use of fermentation in manufacturing processes. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. [1]
The high concentration of lactic acid (the final product of fermentation) drives the equilibrium backwards (Le Chatelier's principle), decreasing the rate at which fermentation can occur and slowing down growth. Ethanol, into which lactic acid can be easily converted, is volatile and will readily escape, allowing the reaction to proceed easily.