[Properties of acylase preparations from an actinomycete culture].

A comparative study of some physico-chemical properties of high-purified preparations of extracellular penicillin-V-acylase and aminoacylase, isolated from the actinomycete Streptoverticillium No 62, revealed the difference in pH and temperature optima, in the sensitivity to the ionic composition of buffer solutions, in the enzyme stability during storage. As for the aminoacylase preparation, its thermostability was studied at different pH values, as well as the effect of specific compounds was tested. Similar to other fungal enzymes, the aminoacylase possesses a wide substrate specificity, and by its stereospecificity can be related to L-aminoacylases, while penicillin-V-acylase is a high-specific enzyme, active against phenoxymethylpenicillin.

[Isolation of a highly pure preparation of cephalexin amidase from bacteria of the genus Xanthomonas].

A procedure for highly purified cephalexin amidase of Xanthomonas was developed. It consists of preparation of a cell-free extract of the culture after cell disintegration, precipitation with ammonium sulfate, dissolution, concentration and elimination of ballast proteins, gel filtration on Sephadex G-25, sorption of ballast proteins on DEAE cellulose and chromatography on KM-cellulose. The enzyme yield is 45-55 per cent.

[Isolation and comparative characteristics of acylase preparations from various antinomycete cultures].

The procedure for isolation of acylases from the fermentation broth filtrates of 3 actinomycetous cultures was developed with a yield of 72-97 per cent and 11-19- fold purification of the preparations. Comparative study of substrate specificity of acylase preparations showed that all of them possessed 2 types of the activity, i.e.

[Acylase activity of groups of actinomycetes and bacteria].

The acylase activity of 113 actinomycetous strains and 71 bacterial strains was studied. A number of strains producing acylases, hydrolyzing phenoxymethylpenicillin was detected among the actinomycetous cultures and a number of strains producing acylases active against ampicillin and benzylpenicillin was detected among the bacterial cultures. These acylases may be used in production of semisynthetic beta-lactam antibiotics and their semiproducts.

[Microbiological transformation of cephalosporin C].

Bacteria and actinomycetes were screened for finding organisms that produced enzymes transforming cephalosporin C. Different bacteria were found to be capable for producing enzymes that degraded cephalosporin; actinomycetes possessed this capability to a lesser extent. The transformation of cephalosporin was catalyzed by beta-lactamase and acetyl esterase.

[Nitrogen metabolism characteristics of P. chrysogenum in relation to penicillin biosynthesis].

Quantitative correlation between the nitrogen level in the mycelium of P. chrysogenum and biosynthesis of penicillin was shown. With an increase in the nitrogen level of the mycelium, its productivity with respect to the formation of the antibiotic also increased.

[Characteristics of cephalosporin C biosynthesis on a synthetic medium].

The attitude of the cephalosporin C-producing organism to various sources of carbon and nitrogen was studied. Carbohydrates such as maltose, starch and sucrose and nitrogen sources such as mineral ((NH4)2SO4 + KNO3) and organic nitrogen (asparagine) may be successfully used for the culture growth and antibiotic biosynthesis. The use of the mineral nitrogen necessitates additional regulation of pH during the cultivation process.

[Penicillin biosynthesis and amino acid metabolism in Penicillium chrysogenum in experiments with washed mycelium].

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.

[Physiological role of fats in the process of penicillin biosynthesis].

The level of penicillin production in the presence of whale oil was shown to be higher. The stimulating effect of the oil was connected with accumulation of large biomass rather than with its specific effect on the biosynthesis. At the beginning of the process the oil eliminated the biomass accumulation lag-phase connected with beta-galactosidase repression by glucose.

[Preparation of extracellular ribonuclease form Actinomyces rimosus 994].

By sequential acid treatment, gel filtration and KM-cellulose sorption a 18--20-fold purified preparation of ribonuclease with a yield of 50--60% was obtained from the culture liquid filtrate of Actinomyces rimosus 994. The preparation had a high specific activity of 450,000--600,000 units/mg protein, contained 85--98% protein, insignificant amounts of carbohydrates and hydroxytetracycline, and no quantities of DNase, phosphomonoesterases, phosphodiesterase or proteases. In RNA degradation (preparation of the total yeast RNA of the Sigma Co.

[Penicillium chrysogenum mycelial productivity in the 1st phase of penicillin biosynthesis].

The course of the mycelium low productivity during the first phase of the usual two-stage process of penicillin biosynthesis was studied. It was found that the low productivity of the mycelium at the beginning of the fermentation process was probably associated with catabolic regression of the penicillin-producing system. The high specific growth rate registered in the experiments (0.

[Characteristics of fucidin biosynthesis by a Fusidium coccineum 257 A strain].

The physiological features of Fusidium coccineum, strain 257 A, an organism producing fusidin were studied. It was found that increased concentrations of the carbon sources in the medium stimulated production of fusidin, while an increase in the content of various forms of nitrogen differently affected the level of the antibiotic viosynthesis: high concentrations of the amino acid-peptide form of nitrogen of corn-steep liquor decreased, while the protein form of nitrogen was associated with consumption of the significant part of carbon in the medium for formation of the fungus mycelium. Therefore, the concentration of the easily mobilizing forms of nitrogen may be considered as a regulator of the growth process of F.

[Physico-chemical properties of 7-aminodesacetoxycephalosporanic acid].

7-Aminodesacetoxycephalosporanic acid (7-ADCA) of 99 per cent purity was prepared by enzymatic hydrolysis of 7-phenylacetamidodesacetoxycephalosporanic acid. Its isoelecti point was determined by the electrophoretic method. Potentiometric titration of zwitterion of 7-ADCA was performed and the constants of its ionization were calculated.

[The nucleases of oxytetracycline producing actinomycetes].

The activity of exocellular nucleases, especially RNase, differs among cultures producing oxytetracycline, and belonging or similar to Actinomyces rimosus, and cultures which are not related to this species. The activity of RNase therefore may be regarded as an additional taxonomic characteristic within the species Act. rimosus.

[Some characteristics of fucidin biosynthesis].

Some features of fusidin biosynthesis by 2 strains of Fusidium coccineum were studied proceeding from the peculiar properties of the antibiotic molecule structure. It was found that an increase in the levels of the carbon sources in the medium stimulated the biosynthesis of fusidin, while excessive concentrations of nitrogen especially in its inorganic and amino acidpeptide forms stimulated the organism growth and lowered the antibiotic activity levels. The concentration of nitrogen in the medium is considered as one of the possible control mechanisms in the processes of the fungus growth and biosynthesis of fusidin.

[Metabolites toxic for penicillin biosynthesis in P. chrysogenum fermentation].

Substances toxic for biosynthesis of penicillin accumulated in the medium at the end of the process during penicillin fermentation. Accumulation of such substances was associated with the mycelium autolysis. Addition of nutrient substances as soon as they are consumed prevented autolysis of the mycelium and accumulation of the toxic metabolites.

[Study of the mycelial carbohydrates of Penicillium chrysogenum and of its inactive mutant].

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.

[Biosynthesis of penicillin and the biphasal development of a P. chrysogenum culture].

The two-phase pattern of penicillin biosynthesis was observed only under definite cultivation conditions. When the conditions of the culture growth changed, the productivity curve also changed. The most high productivity levels on the glucose medium and the medium with glucose and lactose were noted at the beginning and in the middle of the process respectively.

[Carbon metabolism under conditions of regulated penicillin biosynthesis].

Carbon metabolism of P. chrysogenum under conditions of periodical addition of the nutrients was studied. It was found that a proper rate of the carbon source addition to the culture was of significant importance for intensive biosynthesis.