[Effect of partial pressure of solute oxygen on the intensity of respiration of cultures of antibiotic producers]. / Vliianie partsial'nogo davleniia rastvorennogo kisloroda na intensivnost' dykhaniia kul'tur-produtsentov antibiotikov.

It was shown possible to use feeding of hydrogen peroxide as a method for investigating the impact of dissolved oxygen concentrations on growth and development of microorganisms. The influence of pO2 on the respiration intensity was studied in penicillin- and erythromycin-producing cultures and it was found that dependence of the respiration intensity on pO2 had the form of a curve with saturation, at pO2 equal to zero the value of the culture respiration intensity being different from zero. A mathematical model accounting for the presence in the fermentation broth of microbial agglomerates with the average size depending on the agitation conditions is proposed for describing the relationships.

[Effect of dissolved carbon dioxide on the tetracycline biosynthesis process in an industrial fermenter]. / Issledovanie vliianiia rastvorennogo yglekislogo gaza na protsess biosinteza tetratsiklina v promyshlennom fermentatore.

The data on changes in the partial pressure of carbon dioxide (pCO2) dissolved in the fermentation broth in the course of biosynthesis of tetracycline made in a 63 m3 fermenter are presented. It is shown that pCO2 equal approximately to 2 cPa was optimal for tetracycline biosynthesis. The total carbonate concentration and pCO2 were estimated simultaneously in the process of tetracycline fermentation.

[Ambiguous relationship between the rates of biomass growth and metabolic product biosynthesis under conditions of multifactorial limitation and inhibition]. / Neodnoznachnost' sviazi mezhdu skorostiami rosta biomassa i biosinteza produktov metabolizma v usloviiakh mnogofaktornogo limitirovaniia i ingibirovaniia.

Theoretical analysis of the relationship between the rates of the biomass growth mu and biosynthesis of the metabolites q was performed, when the both kinetic characteristics depended not on one, but on two and more environmental factors. Apparently similar effects of the factors on the biomass growth and biosynthesis (limiting, inhibition or combined limiting-inhibition) at different values of the kinetic equation constants were studied. Examples of different character of the effects of one or both factors on the growth and biosynthesis are discussed. In all cases it was found that relationship q (mu) was uncertain. The relationship pattern was connected with the fact, by means of which the culture growth was controlled, while the absolute values of the kinetic characteristics depended on the value of the second unchangeable factor. When relationship q (mu) was obtained by means of correlation between the experimentally found values of q and mu at accidentally changed factors of the environment, the relationship form could be anyone and not connected with any regularities of the microbiological process. Setting up an equation for mathematical description of relationship q (mu) in such cases is not correct. The only exception is the process, in which biosynthesis is directly connected with the culture growth rate.

[Macrokinetic equations of pH effect on the growth of Actinomyces aureofaciens and biosynthesis of tetracycline]. / Makrokineticheskie upravleniia vliianiia pH na rost Act. aureofaciens i biosintez tetratsiklina

The effect of pH on the culture respiration rate at different concentrations of glucose in the medium was studied. It was found that the hydrogen ions showed their effect irrespective of the subsrate concentration in the medium. In this connection a type of macrokinetic equations of the effect of pH on the growth and antibiotic biosynthesis was chosen. The constants of the model were determined.

[Mathematical model of the effect of inorganic phosphorus on the tetracycline biosynthesis process]. / Matematicheskaia model' vliianiia neorganicheskogo fosfora na protsess biosinteza tetratsiklina

A special apparatus with continuous dosing of substrates to flasks was used for experiments on the effect of inorganic phosphorus concentrations on the growth process of Act. aureofaciens and tetracycline biosynthesis. The experimental data showed that the character of the orthophosphorus effect on the mycellium growth and antibiotic biosynthesis was different. The relations were described with macrokinetic equations of Mono and Andrus type.

[Effect of orthophosphate on the growth rate and biosynthesis of tetracycline by an Actinomyces aureofaciens culture]. / Vliianie ortofosfata na skorost' rosta i biosintez tetratsiklina kul'turoi Actinomyces aureofaciens

A low initial rate of the culture growth is an obligatory condition for intensive biosynthesis of tetracycline by Act. aureofaciens in batch fermentations. The mineral phosphorus concentration is a factor limiting the growth rate. Under conditions of model experiments, the maximum specific rate of the culture growth equaled to 0.07--0.08 hours-1 was observed in the presence of at least 40 gamma/ml of phosphorus: such a rate correlated with the mycelium productivity equaled to 0.40--0.42 gamma/mg/hour. Cultures growing at a rate of 0.02--0.03 hours-1 were most productive (4.8--4.2 gamma/mg/hour). Such a rate was attained at the phosphorus concentration of 25--30 gamma/ml.