Effect of media composition on the penicillin production.

The conventional penicillin fermentation medium is composed of corn steep liquor, glucose, lactose, minerals, oil, and precursor. The penicillin activity was not affected, due to the addition of carbonate 0-1% or whale oil 0.5% instead of 1%. Also the omission of cupric, magnesium, manganese, zinc sulphates, and acetic acid did not affect the penicillin activity, while the omission of ammonium nitrate and potassium dihydrogen phosphate decreased the penicillin activity in the medium. The penicillin activity of a medium containing 2% calcium superphosphate was higher than that of the control medium, containing 0.4% potassium dihydrogen phosphate and 1% calcium carbonate. Instead of adding the precursor twice, after 0 and 48 hrs, the addition of phenylacetamide in the amount of 0.2%, at the start, did not affect the activity, while addition of phenylacetic acid (0.2%), at the start, decreased the penicillin activity. The omission of the precursors in the medium decreased the penicillin activity measured microbiologically, however, 6-aminopenicillanic acid content was relatively higher as compared with that of the control medium, containing precursor. These results were confirmed, using iodometric assay and paper chromatographic analysis.