Rennets are milk coagulating enzymes. Marzyme is a vegetarian coagulant derived from Mucor Miehei. It is suitable for halal and kosher diets and is GM free. Animal Rennet comes directly from calves and is used in more traditional cheese types. It too is GM free. Both of the rennet milk coagulating enzymes, Vegetarian and Animal, can be used in a wide range of cheese types.