What other products are obtained from the fermentation of carbohydrates to produce ethanol?

This post was last edited by cl6119 on 2011-7-27 at 14:14. You are using the Synchronous Saccharification Fermentation process (SSF). It depends on what kind of fungus you use. With ordinary yeast, one can only utilize 6C sugars such as fructose and glucose, but not 5C sugars such as xylose ； The fermentation rate of good ethanol is 92% of the theoretical value. A passage from the book discusses the composition of the fermented mature broth. This broth is a complex mixture, and its components depend to a large extent on the type of raw materials used as well as the production processes employed. Taking a fermented mature mash made from corn flour as an example, its composition is generally as follows: about 80% (W) water, about 6% (W) dry matter, and 8%–12% (V) ethanol and volatile impurities. The fermentation broth always contains a certain amount of CO2, with its concentration ranging from 1 to 1.5 g/L ； The fermentation broth is acidic, with a pH value of 4–5. Non-volatile impurities: The non-volatile impurities in corn starch fermentation broth mainly include yeast cells, insoluble starch, and other insoluble substances such as short fibers present in corn starch. In addition, there are also unfermented residual sugars, dextrins, residual proteins, inorganic salts, glycerol, succinic acid, lactic acid, and other non-volatile metabolic products of microorganisms. Non-volatile impurities in the mature mash are relatively easy to remove; these impurities, along with most of the water in the mash, are discharged at the bottom of the mash tower. This discharged mixture is known as alcohol lees, or simply lees. The alcohol leachate produced by liquid fermentation is in large quantities and has a high organic content; if discharged directly without treatment, not only are these organic substances wasted, but it also easily leads to environmental pollution. In recent years, with the expansion of the alcohol industry and technological advancements, significant progress has been made in the comprehensive utilization of alcohol distillers’ residues: most grain-based distillers’ residues are used to produce protein feed ； Potato distillers’ grains are processed using biogas fermentation ； Molasses and distillers’ grains are used to make compound fertilizers. Volatile impurities: Volatile impurities mainly include fusel oils, aldehydes, acids, and esters, etc. Their types and concentrations depend on the raw materials and the manufacturing process. Methanol mainly comes from the decomposition of pectin in the raw materials ； Isopentanol, isobutanol, and n-propanol are the main components of fusel oils; they are products of the fermentation process, and their concentration can range from 0.3% to 0.5% (V) of the total alcohol content ； Aldehydes are mainly acetaldehyde; the acetaldehyde content in fermented alcohol broths produced from molasses is relatively high, accounting for about 0.05% (V) of the total alcohol content ； Acetic acid, butyric acid, propionic acid, lactic acid, and valeric acid are primarily produced by contaminants during the fermentation process, and their concentration can account for 0.005% to 0.1% (V) of the total alcohol content ； The esters mainly include ethyl acetate, ethyl formate, methyl acetate, and ethyl isobutyrate, with a content of about 0.05% (W) of ethanol.

Look it up online, ah; I really don’t know