[Express method of determining phenylacetic acid in the culture broth during the biosynthesis of benzylpenicillin]. / Ekspress-metod opredeleniia feniluksusnoi kisloty v kul'tural'noi zhidkosti pri biosinteze benzilpenitsillina.

Phenylacetate acid (PAA) is transferred by extraction from the fermentation broth filtrate into toluol. The extract is applied to a Silufol plate with an aluminium foil lining (silica gel sorbent, Czechoslovakia). Reference solutions of PAA are also applied to the same plate. The reference and test solutions are applied dropwise (spots of 5--6 x 10(-3)m in diameter). For PAA development the spots are sprayed with a freshly prepared saturated solution of potassium manganate in 6N H2SO4. PAA of the test samples is developed as a dull ring against grey background and that of the reference solution is developed as a circle. The amount of PAA in the spot is determined by using correlation between the spot area and the amount of PAA applied. One plate of 225 X 10(-4) m2 can be used for about 300 analyses. One analysis takes 300--600 seconds.

[Penicillin biosynthesis and amino acid metabolism in Penicillium chrysogenum in experiments with washed mycelium]. / Biosintez penitsillina i aminokislotnyi metabolizm u Penicillium chrysogenum v opytakh s otmytym mitseliem.

The study of the amino acid metabolism in Penicillium chrysogenum with the use of washed mycelium showed that the amount of the free intracellular amino acids significantly decreased during the process of penicillin production. Still, such a decrease did not cover the nitrogen requirements of the culture for the antibiotic synthesis and mobilization of the protein nitrogen took place. By the end of the process the amount of the protein nitrogen markedly decreased. At the same time alpha-amino nitrogen was absent in the fermentation broth filtrate. About 14 amino acids (including cysteine and valine) which participate in constriuction of the penicillin molecule nucleus were found in the amino acid poll. However, the amounts of cysteine and valine were not high and probably other free intracellular amino acids participated in their synthesis. It was shown that one of the limiting factors in the process of penicillin biosynthesis was synthesis of cysteine, a sulphur-containing amino acid which is one of the precursors of the antibiotic molecule nucleus.

[Study of the mycelial carbohydrates of Penicillium chrysogenum and of its inactive mutant]. / Issledovanie uglevodov mitseliia Penicillium chrysogenum i ego neaktivnogo mutanta

Metabolism of carbohydrates was studied in Penicillium chrysogenum 194 and in its inactive mutant growing on a defined medium, and also in the washed mycelium of these cultures. The percentage of nitrogen decreased in the mycelium of both strains with aging as a result of the accumulation of carbohydrate-containing substances dissolved in cold and hot hydrochloric acid. The rate of synthesis of these substances in the inactive mutant is higher than in the strain 194. The difference is especially pronounced in experiments with the washed mycelium. Carbohydrates dissolved in the hot acid are assimilated in largest amounts among carbohydrate-containing substances in the mycelium of the strain 194 growing in the conditions of starvation.