How Lipase Works:
Lipase is an enzyme that causes lipolysis, which is the breaking down of the fat in the cheese, releasing free fatty acids in the process.
Triglycerides, which make up about 95 percept of our dietary fats, and which are present in milk, give an oily sensation in the mouth, but have little to no flavour. Lipase attaches itself to the fats in milk and breaks them down into fatty acids. Fatty acids, in most cases, have a chain of an even number of carbon atoms and can be long or short. It is the short chains that give us the strong and characteristic flavours in cheeses traditionally made with lipase, such as Romano and Parmesan.
For a more in depth study, and detailed scientific information on cheese we highly recommend "Fundamentals of Cheese Science" by Patrick F Fox, Timothy P Guinee, Timothy M Cogan, Paul L H McSweeney.
This book is ideal for anyone who really wants to understand the microbiology of cheese making.