Conversion of sugar to alcohol

Prior to the breakthrough by E.Buchner s investigations, Berthelot had tried to demonstrate cell-free (and thus chemical or enzymatic nature of the) conversion of sugar to alcohol in the 1850 s, but indeed his approach could not be successful, as was obvious from Pasteur s clarification of the manifold somces of microbial infection, notably inoculation from the air. It was these findings which were a condition for Buchner s concept to exclude microorganisms (at least to an essential extent, as he was able to show) in his experiments. The progress in understanding and methods thus was necessaiy for the chemical approach, even if Pasteur opposed it himself... 

Fermentation The conversion of sugar to alcohol and carbon dioxide, performed by microbes. 

Fermentation Chemical conversion of sugar to alcohol or acids by the action of yeast or some kinds of bacteria or by muscle cells. 

Many other known and unknown changes of minor importance occur during the fermentation even when it is running its proper course. Coagulation of a portion of the albuminous and pecti-nous substance present may be mentioned as an example. However, the main changes have been indicated and the key to all is the conversion of sugar to alcohol. 

Of course the kind of land needed is quite different. Whereas solar energy can be harvested on the roofs of houses or in unfertile but sunny deserts, arable land is needed for biomass conversion of sugar or alcohol (at least wood should be able to grow). 

Catalysis is not a new phenomenon, but its intentional utilization by humans has begun only in this century. One of the first catalytic processes was probably the fermentation of fruits to obtain alcoholic beverages. Enzymes found in yeast were used as catalysts for the conversion of sugar into alcohol. In fact, ancient Sumerians described beer preparation on... 

Crushing—Maceration—Pressing Operations. Fundamental to making any type of wine is the conversion of sugar to ethyl alcohol by the enzymes present in living yeast cells according to the equation established by Gay-Lussac,... 

Ruthenium is especially effective for the conversion of sugars to polyhydroxy alcohols. The hydrogenation requires elevated temperatures and pressures. 

Fermentation, an original chemical process that was discovered in ancient times, led to the production of wine and beer. With relatively crude techniques, a simple enzyme contained in yeast was found to catalyze the conversion of sugar into alcohol. Control of the ingredients in the fermentation broth would impact the flavor of the alcohol, and the effectiveness of the conversion was controlled by the length of time the fermentation was allowed to proceed and the temperature of the reaction. 

In contrast with the well-known Embden-Meyerhof-Pamass glycolysis pathway for the conversion of hexose sugars to alcohol, the steps in conversion of ethanol to acetic acid remain in some doubt. Likely, ethanol is first oxidized to acetaldehyde and water (39). For further oxidation, two alternative routes are proposed more likely, hydration of the acetaldehyde gives CH2CH(OH)2, which is oxidized to acetic acid. An alternative is the Cannizzaro-type disproportionation of two molecules of acetaldehyde to one molecule of ethanol and one molecule of acetic acid. Jicetobacter... 

Starches. In the United States, all potable alcohol, most fermentation industrial alcohol, and most fuel alcohol is currendy made principally from grains com is the principal feedstock for fuel alcohol. Fermentation of starch from grain is somewhat more complex than fermentation of sugars because starch must first be converted to sugar and then to ethanol. This process was known to the ancient Egyptians and Mesopotamians who brewed beer almost 5000 years ago (202). The simplified equations for the conversion of starch to ethanol are... 

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