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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.
This definition distinguishes fermentation from aerobic respiration, where oxygen is the acceptor and types of anaerobic respiration, where an inorganic species is the acceptor. [citation needed] Fermentation had been defined differently in the past. In 1876, Louis Pasteur described it as "la vie sans air" (life without air). [7]
In yeast, pyruvate decarboxylase acts independently during anaerobic fermentation and releases the 2-carbon fragment as acetaldehyde plus carbon dioxide. Pyruvate decarboxylase creates the means of CO 2 elimination, which the cell dispels. The enzyme is also means to create ethanol, which is used as an antibiotic to eliminate competing ...
Chemical structures showing ethanol fermentation In beer, the metabolic waste products of yeast are a significant factor. In aerobic conditions, the yeast will use in the glycolysis the simple sugars obtained from the malting process , and convert pyruvate , the major organic product of glycolysis, into carbon dioxide and water via the cellular ...
Fermentation of glucose, the main product of cellulose hydrolyzate, to ethanol is an already established and efficient technique. However, conversion of xylose, the pentose sugar of hemicellulose hydrolyzate, is a limiting factor, especially in the presence of glucose.
Ethanol is the most commonly used biofuel and can be produced on large scale via fermentation. The maximum theoretical yield for the production of ethanol was achieved around 20 years. [14] [15] A plasmid that carried the pyruvate decarboxylase and alcohol dehydrogenase genes from the bacteria Z. mobilis was used by scientists.
Because fermentation produces ethanol, which has a lower density than water (gravity of 0.787 at 25°C [3]), the apparent attenuation overestimates the actual percentage of sugars consumed. [4]
The word's meaning became restricted to "spirit of wine" (the chemical known today as ethanol) in the 18th century and was extended to the class of substances so-called as "alcohols" in modern chemistry after 1850. [16] The term ethanol was invented in 1892, blending "ethane" with the "-ol" ending of "alcohol", which was generalized as a libfix ...