[Interdependence of mycelial dehydrogenase activity in Streptomyces aureofaciens and its capacity for tetracycline biosynthesis]. / Vzaimozavisimost' degidrogenaznoi aktivnosti mitseliia Streptomyces aureofaciens i ego sposobnosti k biosintezu tetratsiklina.

The maximum dehydrogenase (oxidation-reduction) activity of the vegetative inoculum of S. aureofaciens is the criterion of its availability for transfer to the fermentation medium. The activity is determined by the rate of the methylen blue reduction and the growth characteristics of the seed culture. A method for estimation of the mycelium amount in the medium containing insoluble solid particles is described. The method is based on the capacity of the tetracycline-producing organism for decoloration of methylen blue.

[Possibility of the spectral analysis of heterogeneous biological systems. The determination of the mycelium concentration of Actinomyces aureofaciens, a producer of tetracycline, cultured on a medium with corn meal]. / O vozmozhnosti spektral'nogo analiza geterogennykh biologicheskikh sistem. Opredelenie kontsentratsii mitseliia Actinomyces aureofaciens--produtsenta tetratsiklina, kul'tiviruemogo na srede s kukuruznoi mukoi.

A possibility of using spectroscopy of attenuated total reflection in the IR region for analysis of the heterogenic system consisting of the microorganisms and plant cells is discussed. The method of spectroscopy is proposed for estimating the mycelium concentration of Act. aureofaciens producing tetracycline in the presence of corn meal in the medium. The experimental data confirming this possibility are presented. The peculiar properties of the spectral analysis under these particular conditions are discussed. It is supposed that the method may be used for analysis of heterogenous systems including other microorganisms.

[Morphofunctional study of the development of Actinomyces aureofaciens under conditions of regulated and unregulated fermentation]. / Morfofunktional'noe izuchenie razvitiia Actinomyces aureofaciens v usloviiakh reguliruemoi i nereguliruemoi fermentatsii.

Actinomyces aureofaciens producing tetracycline and its inactive proactinomyces-like variant were studied by electron microscopy during their growth under conditions of regulated and non-regulated fermentation. The ultrastructure of the active variant changed: the cell wall and ribosomes underwent modification, amorphous electron-transparent structures appeared, and tubular membrane structures were formed. No changes were found in the inactive variant. When Act. aureofaciens grows in conditions of non-regulated fermentation, it shows rapid disintegration and autolysis; then, wide fragmented hyphae are formed. The morphology of these hyphae is similar to that of spore forming hyphae of the aerial mycelium. Viable hyphae exist for a long time if the active culture grows in conditions of regulated fermentation with periodic addition of nutrient substances. Amorphous electron-transparent structures, apparently of the antibiotic nature, are formed in the hyphae and liberated into the medium.

[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.

[Effect of dissolved carbon dioxide on tetracycline biosynthesis]. / Vlianie rastvorennogo uglekislogo gaza na biosintez tetratsiklina

The paper presents data on the effect of CO2 dissolved in the fermentation broth on biosynthesis of tetracycline. It was shown that there was optimal concentration of CO2 for the tetracyline-producing organism. As a result of the experiments the ranges of the optimal concentrations within 2 to 8 ml of CO2 per 100 ml of the fermentation broth 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.

[Regulation of tetracycline biosynthesis by controlling the growth of the producer]. / Reguliatsiia biosinteza tetratsiklina putem upravleniia rostom produtsenta

Regulation of the rate growth of Act. aureofaciens in batch fermentation by maintaining the concentrations of phosphorus, ammonium nitrogen, glucose and pH values at the levels favourable for intensive growth at the beginning of the process and after accumulation of the biomass at the levels optimal for retarded growth of the organism resulted in significant prolongation of the period of intensive antibiotic production, i.e. intensification of the fermentation process. Microscopic investigation of the organism development under conditions of regulated fermentation revealed the presence of significant amounts of free peripheral highly basophilic hyphae for a prolonged period of time. The hyphae possessed a capacity for growth and intensive metabolism unlike the control culture which was liable to early autolysis.

[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.