History of penicillin History of penicillin The history of penicillin follows a number of observations and discoveries of apparent evidence of antibiotic activity in molds before the modern isolation of the chemical penicillin in 1928. There are anecdotes about ancient societies using molds to treat infections, and in the following centuries many people observed the inhibition of bacterial growth by various molds. However, it is unknown if the species involved were "Penicillium" species or if the antimicrobial substances produced were penicillin. The Scottish physician Alexander Fleming was the first to suggest that a "Penicillium" mold must secrete an antibacterial substance, and the first
Penicillin lactose does not. The pH and the levels of nitrogen, lysine, phosphate, and oxygen of the batches must also be carefully controlled. The biotechnological method of directed evolution has been applied to produce by mutation a large number of "Penicillium" strains. These techniques include error-prone PCR, DNA shuffling, , and strand-overlap PCR. Semisynthetic penicillins are prepared starting from the penicillin nucleus 6-APA. Overall, there are three main and important steps to the biosynthesis of penicillin G (benzylpenicillin). Penicillin Penicillin (PCN or pen) is a group of antibiotics which include penicillin G (intravenous use), penicillin V (use by mouth), procaine penicillin,