Ethanol
Overview
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest used. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a solvent, a fuel, and starting material for Polyethylene from Ethanol. In common usage, it is often referred to simply as alcohol or spirits.
Ethanol Production
Ethanol is organically produced by fermentation in a variety of microorganisms including yeasts and bacteria. Ethanol fermentation is an art that has been employed for thousands of years and is of significant commercial and recreational value. Commodity ethanol is valued according to its purity while consumption ethanol is valued by creating a palatable beverage and their production processes have these emphasis. Fermentation requires a carbohydrate rich feedstock, a fermentative microorganism, and a chamber to protect from contamination and control conditions. Beers are filtered, while liquors and commodity ethanol is distilled to a higher purity.
Feedstocks
Carbohydrate rich plants containing either simple sugars or starch are ideal fermentation material. Saccharomyces prefers glucose but can also use other disaccharides and simple sugars.
Microorganisms
The yeast Saccharomyces cerevisiae (brewers yeast) is the most widely used ethanol fermenting microorganism. The bacterium Zymomonu mobilis is also used in its own or with yeast. It produces ethanol by the Entner–Doudoroff pathway near the theoretical limit and is under biotechnology study.
Fermentation chamber
An OSE fermentor is currently in research and development for production of ethanol, lactic and acetic acid.
Distillation
Ethanol is purified via distillation to either high purity for industrial use or a liquor spirits. Distillation equipment is well understood for purification of the (95%:5%) ethanol:water azeotrope and multiple online resources discuss their open construction. However for OSE's purposes higher purity (99%+) ethanol must eventually be rendered. Drying agents and vacuum distillation are two methods OSE should investigate to these ends.