The effects of some types of mold on infection had been noticed many times over the course of history (see: History of <answer>penicillin</answer>). In 1928, Alexander Fleming noticed the same effect in a Petri dish, where a number of disease-causing bacteria were killed by a fungus of the genus Penicillium. Fleming postulated that the effect is mediated by an antibacterial compound he named <answer>penicillin</answer>, and that its antibacterial properties could be exploited for chemotherapy. He initially characterized some of its biological properties, and attempted to use a crude preparation to treat some infections, but he was unable to pursue its further development without the aid of trained chemists.
What mold did Fleming notice had antibacterial properties?
penicillin