[Effect of the producer type on the nature of antibiotic fermentation]. / Vliianie tipa produtsenta na kharakter fermentatsii antibiotikov.

Fermentation processes in production of bacitracin, a polypeptide antibiotic by Bacillus licheniformis, and oleandomycin, a macrolide antibiotic by Streptomyces antibioticus, were studied comparatively. It was shown that the antibiotic-producing actinomycete was characterized by a prolonged phase of growth retardation. The highest efficiency of the control actions was observed at the beginning of the fermentation. They were aimed at intensifying the substrate usage during the growth phase and activation of cell metabolism. Controlled cultivation of the Bacillus representative was based on its capacity of achieving the maximum growth rate possible under the certain conditions. Therefore, an increase in the quantity of the synthesized antibiotic was due, under such conditions, to inhibition of the culture growth by various means including lower mass exchange intensity.

[Application of a method of material-energy balance for controlling the process of microbiological synthesis of riboxin]. / Primenenie metoda material'no-énergeticheskogo balansa dlia upravleniia protsessom mikrobiologicheskogo sinteza riboksina.

Possible control of riboxin biosynthesis on the basis of the information provided with the method of material-energy balance was studied. Correspondence of the cultivation conditions to the directed biosynthesis was established by comparing the experimental values of the respiration coefficient delta CO2/delta O2, the coefficient of constructive and energy metabolism conjugate Cc/e and the ratio of the consumed amounts of glucose and ammonium nitrogen delta S/delta NH4+ with the theoretical values of these parameters. The control principle included changing of the process operation parameters for providing cultivation conditions approximating the experimental values of Cc/e, delta CO2/delta O2 and delta S/delta NH4+ to their theoretical values. It was shown possible to control directed aerobic growth of the culture by changing the aeration conditions. A decrease in the initial aeration rate promoted more rapid transition of the microbial population to the exponential growth phase and provided for a certain period cultivation conditions corresponding to the conditions of conjugate metabolism. It was found that the respiration coefficient could be used not only as a parameter reflecting one of the forms of the cell physiological activity manifestation but also as an optimization criterion in development of a controlled cultivation process.

[Assessment by the material and energy balance method of the directed biosynthesis of riboxin by altering the external culture conditions]. / Otsenka metodom material'no-énergeticheskogo balansa napravlennogo biosinteza riboksina pri izmenenii vneshnikh uslovii kul'tivirovaniia.

The effect of various agitation conditions on growth of the cell population of Bacillus subtilis and production of riboxin was studied. The physiological state of the culture was estimated by the relations for the respiration coefficient CO2/O2, the yield of the constructive metabolism products (X + P) by oxygen Yx + p/O2, the ratio of consumed glucose to ammonium nitrogen S/NH4+, the coefficient of the cell biosynthetic activity Yp/x and the parameter of the energetic efficiency of the substrate usage (eta). It was shown that the maximum biosynthetic activity was mainly defined by the culture state in the trophophase. The growth of the cell population in this case should proceed under conditions of conjugated aerobic metabolism. It was found that directed biosynthesis of riboxin could be provided by changing the cultivation conditions and estimation of the culture physiological state by the parameters of the material and energy balance.