Penicillin

Abstract

Phenylacetic acid, when added to surface cultures of Penicillium notatum NRR 1249.B21 and to submerged cultures of P. notatum NR 832 or P. chrysogenum NRRL 1951.B25, gave marked creases in total penicillin yield. Only in the presence of whole wheat bran in submerged culture was evidence obtained that phenylacetic acid had an effect on the type of penicillin produced. The toxicity of phenylacetic acid could be sufficiently overcome by raising the pH prior to inoculation or by adding the phenylacetic acid during the fermentation after the pH had risen above the critical level. The optimum conc. of phenylacetic acid was between 0.2 and 0.8 g. per liter of medium.