What molecules does amylase enzyme work on? I know that in the human body cellulose cannot be broken down by enzymes; however, I am confused as to which molecules amylase enzymes during fermentation. I also looked at < where it says that "All amylases are glycoside hydrolases and act on α-1,4-glycosidic bonds." so now I am confused. Does amylase work to break down starch into glucose exclusively? If not... Does amylase enzyme break down corn cob extract which contains xylans, cellulose, lignin and some sugar for fermentation? Does amylase enzyme break down corn stem which contains cellulose, hemicellulose and lignin for fermentation?

Your incomprehension is due to the fact that both starch and cellulose are polysaccharides.

As it is said in the wiki page. Amylase is active only on alpha linkage like starch or glycogen. If you want to break beta linkage like in cellulose you need a cellulase enzyme, which humans do not have.