What organism is penicillin derived from?

Answer: Penicillin G (also called benzylpenicillin) was discovered by accident in 1928. Alexander Fleming, a Scottish physician-scientist was growing a type of bacteria called Staphylococcus Aureus on an uncovered petri dish when it became contaminated with mold spores.

Penicillium mold naturally produces the antibiotic penicillin.