Production of penicillin

here is only one choice for the antibiotic production process: the synthesis of benzyl-
penicillin (penicillin G, originally known as ‘penicillin’). This, the most renowned antibi-
otic and the first one have been manufactured in bulk, is still universally prescribed.5
Although originally made by surface liquid culture, penicillin G is now produced by air-lift
fermentation under aerated conditions.
Penicillin G is not a typical fermentative antibiotic. It is made by a fungus, Penicillium
chrysogenum. The number of antibiotics from fungal sources is few, though they do include
penicillin G and V and cephalosporin C. These three antibiotics are the major starting mate-
rials for the semi-synthetic -lactam antibiotics. The systemic antifungal antibiotic griseo-
fulvine is also of fungal origin. Most antibiotics are produced by fermentation using
bacteria, including streptomycin and the tetracycline family among numerous others. The
manufacture of streptomycin from Streptomyces griseus will not be considered in this
experiment. Streptomycin is the next important antibiotic after penicillin G to be made
available to the clinician. It has played an important role in fighting tuberculosis All of the above processes are operated as batch fermentations, in which a volume of
sterile medium in a vessel is inoculated. The broth is fermented for a defined period. The
tank is then emptied and the products are separated to obtain the antibiotic. The vessel is
then recharged for batch operation with medium and the sequence repeated, as often as
required. Continuous fermentation is not common practice in the antibiotics industry. The
antibiotic concentration will rarely exceed 20 g- and may be as low as 0.5 g-