Zymase products

Acetic Fermentation.—Acetic acid in addition to its occurrence in nature in the form of esters is produced on the large scale by the acid fermentation (oxidation) of the alcohol obtained as the result of fermenting fruit juices which contain sugar, especially apple juice or cider, and wine. When the sugar present in cider is fermented, dueTo the action of the enzyme zymase, alcohol is produced (p. 95). This alcohol is then oxidized through the activity of an aerobic bacterial organism Bacterium aceti, which is present naturally in the fruit juice. The product is acetic acid. 

A source of alcohol and alcoholic beverages. The starch of grains, potatoes, etc., is first hydrolyzed by natural sprouting, as in the preparation of barley malt, or by the addition of malt to it. The hydrolytic products, glucose and maltose, are then fermented by the addition of yeast, containing the enzymes, maltase, and zymase, and alcohol is thus produced. This has been fully discussed in the chapter on alcoholic fermentation, (p. 95). 

Many other suggestions have been made regarding the intermediate steps in the conversion of dextrose into alcohol and carbon-dioxide and the nature of the intermediate products. Buchner and Meisenheimer, B. (1905), 38 620, suggested that lactic acid is the first product of the action of zymase on dextrose since it is known that this acid is formed in muscle tissue by the oxidation of glycogen, which is a polydextrose. They added to this theory the assumption of a second enzyme, lactacidase, which carries on the decomposition of the lactic acid into ethyl alcohol and carbon dioxide cf. Bio. Z. (1922), 128 144 and 132 165. This suggestion was based on the observation that a concentrated solution of dextrose when treated with alkali yields about 3% of alcohol on exposure to sunlight. Under similar conditions a more dilute solution gives a 50% yield of lactic acid. 

Dextrose is fermented by the enzyme zymase, which is present in yeast the products are alcohol and carbon dioxide — C6H12O6 = 2C2H6O + 2CO2... 

Extensive research has been extended toward the fermentation of sucrose and giucose into ethanoi. As we saw in Section 1 6.1 2.d, invertase enzymes in yeast can convert sucrose into a mixture of giucose and fructose. An enzyme called zymase, also available in yeast, can then convert glucose into ethanol as part of the fermentation process, creating CO2 as a by-product. A variety of carbohydrate sources can be used in these fermentation steps, including corn, sugar beets, and sugar cane. 

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