The widely used antibiotic obtained from a blue-green mould is Penicillin. It is produced by the Penicillium fungus, which is a type of blue-green mould. Penicillin was discovered by Scottish biologist and pharmacologist Alexander Fleming in 1928. It was the first antibiotic to be discovered and has since become one of the most widely used antibiotics in the world. Penicillin is effective against a wide range of bacterial infections and has saved countless lives since its discovery.