[Dynamics of the changes in microelement composition (cations of iron, copper and arsenic) during the biosynthesis of nystatin]. / Dinamika izmeneniia mikroelementnogo sostava (kationov zheleza, medi, mysh'iaka) v protsesse biosinteza nistatina.

The dynamics of changes in the microelemental composition during cultivation of the nystatin-producing organisms and synthesis of the antibiotic was studied. The microelemental composition of the raw materials and media used for the cultivation was also studied. Interrelation between the dynamics of the changes in the microelemental composition and the main parameters of the process of the antibiotic production were analyzed. It was revealed that during the first stage of the culture development characterized by the maximum rate of the biomass accumulation the ions of ferrum, cuprum and arsenic were consumed along with consumption of the main nutrients (carbohydrates, nitrogen and phosphorus). During the second stage of the culture development i.e. after 36 hours the ferrum ions were liberated into the fermentation broth while the content of cuprum and arsenic continued to decrease though at a lower rate. Marked shifts in the specific rates of the changes in the contents of ferrum and cuprum ions in the fermentation broth were also observed at the beginning of the second phase of the culture development. It was shown possible to control the process of nystatin biosynthesis by the microelemental composition of the media for cultivation of the antibiotic-producing organism.

[Trace elements in raw materials and nutrient media for cultivation of antibiotic-producing organisms]. / Mikroélementy v syr'e i pitatel'nykh sredakh kul'tivirovaniia produtsentov antibiotikov.

The contents of microelements such as Fe, Cu, Zn and As in samples of raw materials including food grade ones used in preparation of nutrient media for cultivation of antibiotic-producing organism and water were determined spectrophotometrically with using complex forming organic reagents. An original procedure for the sample combustion in the assay was developed. The natural background levels of the microelements in the nutrient media used in manufacture of some antibiotics were estimated.