The present study deal with hydrolysis of lactose by kluyveromyces fragilis that grown in Whey and synthetic medium and the effect of incubated temperature and pH on enzyme activity Lactase (ß-galactosidase) that hydrolyze lactose in whey milk and synthetic medium .Also the conversion of glucose that released from lactose hydrolysis by kluyveromyces fragilis into fructose via addition of glucose i...