Bioethanol production is from corn starch. In the corn-to-ethanol process, kernels of corn are ground into a mash and the starch is separated from other corn components. Enzymes are then added to break down the starch into simple sugars like glucose. Yeast is added to the mixture to begin fermentation, converting the sugars into alcohol. After fermentation, the alcohol molecules are s... https://articlescad.com/bioethanol-a-renewable-and-sustainable-fuel-source-358119.html