Aspergillus niger (fungus): It produces citric acid which is employed in dyeing, inks, medicines, flavoring, and preservation of food.
Clostridium butylicum (bacterium): It produces butyric acid which is used to make rancid butter.
Cyclosporin A: It is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum.
Statins: These are produced by the yeast Monascus purpureus. Statins have been commercialized as blood-cholesterol lowering agents. It acts competitively inhibiting the enzyme responsible for the synthesis of cholesterol.