Penicillin is an antibacterial agent, which has a broad spectrum effect on various bacteria. The antibacterial action is selective for group of organism mainly gram positive groups. Penicillin is produced by fungi of genus Penicllium notatum. The penicillin shows antibacterial action by rupturing the cell wall of growing bacterial cells.
Penicillin attacks the NAM (N-acetylmuramic acid)) and NAG (N-acetylglucosamine) of the cell wall. The cell wall acts as a barrier to maintain the osmotic balance of the cell. It contains four membered β-lactam rings fused to a five-membered thiazolidine ring.
The molecule skeleton suggests that it is derived from cysteine and valine. The biosynthesis of penicillin is critical since it is a secondary metabolite released during nutrient deficient condition.
During fermentation different analogues of penicillin are produced by changing the biosynthetic route mainly carboxylic acids. The structure of penicillin seems to have a presence of amino acids such as cysteine and valine. The amino acid has no role in the production of drug penicillin.