Editing Yeast (section)

=== Industrial ethanol production ===
{{See also|Biofuel#Bioalcohols|label 1=Bioethanol}}

The ability of yeast to convert sugar into ethanol has been harnessed by the biotechnology industry to produce [[ethanol fuel]]. The process starts by milling a feedstock, such as [[sugar cane]], [[field corn]], or other [[cereal grain]]s, and then adding dilute [[sulfuric acid]], or fungal alpha [[amylase]] enzymes, to break down the starches into complex sugars. A glucoamylase is then added to break the complex sugars down into simple sugars. After this, yeasts are added to convert the simple sugars to ethanol, which is then distilled off to obtain ethanol up to 96% in purity.<ref name="USDE-2009"/>

''Saccharomyces'' yeasts have been [[genetically engineered]] to ferment [[xylose]], one of the major fermentable sugars present in [[Lignocellulosic biomass|cellulosic biomasses]], such as agriculture residues, paper wastes, and wood chips.<ref name="Brat-2009"/><ref name="Ho-1998"/> Such a development means ethanol can be efficiently produced from more inexpensive feedstocks, making [[cellulosic ethanol]] fuel a more competitively priced alternative to gasoline fuels.<ref name="Madhavan-2012"/>