 Different classes of enzymes were being used to digest these polymers.These digestive enzymes include proteases that digest proteins into amino acids, as well as glycoside hydrolases that digest polysaccharides into simple sugars known as monosaccharides

Microbes simply secrete digestive enzymes into their surroundings, while animals only secrete these enzymes from specialized cells in their guts, including the stomach and pancreas, and salivary glands.The amino acids or sugars released by these extracellular enzymes are then pumped into cells by active transport proteins.