As Florey observed in"too high a tribute cannot be paid to the enterprise and energy with which the American manufacturing firms tackled the large-scale production of the drug. Merck's pilot plant continued to produce several hundred liters of penicillin culture per week using both flasks and tray, and in December, Heatley joined the Merck research staff for several months, where he introduced the Oxford cup plate method of penicillin assay, which soon became a standard method industry-wide.
Later, the Peoria laboratory increased the yield of penicillin still further by the addition of penicillin precursors, such as phenylacetic acid, to the fermentation medium.
Department of Agriculture, participants included research directors Randolph T. In submerged culture fermentation, the mold is grown in large tanks in a constantly agitated and aerated mixture, rather than just on the surface of the medium.
This analysis can be extended by using rare cutting restriction enzymes, thus allowing determination of the chromosomal structure of a region of interest [ 29 ].
Most strikingly, the loss of one of these copies did not result in decreased penicillin production, thus indicating that the copy number is not responsible for high production in P2niaD All experiments were performed in triplicate from at least two independent isolates.
For Penicillium chrysogenum, the fungal producer of the beta-lactam antibiotic penicillin, many production strains carry multiple copies of the penicillin biosynthesis gene cluster.
Fleming asked C.