[Method for developing a controlled process. Study of the possible regulation of rifamycin B biosynthesis]. / Metod razrabotki upravliaemogo protsessa. Issledovanie vozmozhnosti reguliatsii biosinteza rifamitsina B.

A procedure for developing a controlled process for biosynthesis of secondary metabolites is described with reference to rifamycin B as an example. The response of the antibiotic producing culture to changed concentrations of the main nutrients in the initial medium was determined. Mathematical processing of the experimental findings with design of the experiment resulted in defining nutrients such as ammonium sulfate and cornsteep liquor useful for further development of the controlled process.

[A method for developing a controlled process. Development and execution of a program supplying culture medium components for rifamycin B biosynthesis]. / Metod razrabotki upravliaemogo protsessa. Raschet i realizatsiia programmy podpitok komponentami sredy pri biosinteze rifamitsina B.

The study provided data on the rate of consumption of the main nutrients by the rifamycin-producing culture in relation to their content in the initial medium. A program for feeding ammonium sulfate and cornsteep liquor and joint control of both the nutrients was developed and tested. The results of the testing confirmed the practicable precision of the feeding. The control of cornsteep liquor and ammonium sulfate concentrations with the program allowed to increase the yield of rifamycin B by 15 and 20%, respectively. The joint control increased the level of the required product by 25%.

[Study of the conditions for reproducing the processes of antibiotic biosynthesis. Determining the limiting stage of the process of mass transfer of oxygen]. / Issledovanie uslovii vosproizvodimosti protsessov biosinteza antibiotikov. Opredelenie limitiruiushchei stadii protsessa massoperedachi kisloroda.

A theoretical method for estimating limiting stage of oxygen mass transfer is proposed. The method is based on calculation and comparison of particular resistance of separate stages of mass transfer: mass transfer through the gas-liquid boundary, oxygen transport in the liquid phase, mass transfer through the liquid-cell boundary and oxygen consumption by microbial cells. With the proposed method, particular resistance was calculated and conditions for oxygen mass transfer were analyzed in the biosynthesis of sisomicin as an example. As a result the conditions for reproducibility of the process in apparatus of various size were determined.

[Study of the conditions for reproducing the processes of antibiotic biosynthesis. Calculating the process of sisomycin biosynthesis]. / Issledovanie uslovii vosproizvodimosti protsessov biosinteza antibiotikov. Masshtabirovanie protsessa biosinteza sizomitsina.

Conditions were experimentally studied for reproducing sisomicin biosynthesis by up-to-down scaling. It was shown that respiration intensity as a parameter of antibiotic biosynthesis scaling-down had certain limitations connected with multistage oxygen mass transfer. The parameter could be used only when the limiting stages of oxygen mass transfer coincided. It was confirmed experimentally that it was possible to apply the previously proposed theoretical method to estimation of the limiting stage of oxygen mass transfer.