Enzymes that breakdown disaccharides are located a. in the lumen of the small intestine.

Disaccharides need to be broken down into their component subunits (monosaccharides) before their absorption. The reaction that breaks them up is hydrolysis and it is done by enzymes- glucosidases. Glucosidases are located on the brush border of the small intestine, attached to the surface of the epithelial cells. After the catalyzation of these disaccharides, the epithelial cells take up the monosaccharides and transport them inside using ATP energy. From there they are transported into the bloodstream.