[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%.

[Effect of various forms of inorganic nitrogen on the biosynthesis of rifamycin B]. / Vliianie razlichnykh form neorganicheskogo azota na biosintez rifamitsina B.

To study the influence of various forms of inorganic nitrogen on biosynthesis of rifamycin B, ammonium sulfate, ammonium nitrate, ammonium chloride and sodium nitrate were compared. It was shown possible to use mineral salts containing nitrogen in reduced or oxidized form as fermentation medium components. Sodium nitrate induced early alkalization of the fermentation broth, while ammonium nitrate and ammonium chloride induced its early oxidation. Moreover, the chlorine ions inhibited the antibiotic biosynthesis. All this impaired normal development of the culture. Only ammonium sulfate provided the pH levels of the fermentation broth normal for the antibiotic biosynthesis and the highest levels of the antibiotic production. The positive role of this salt was due to the presence of both the ammonium group and the sulfogroup in the fermentation medium, since addition of the sulfogroup contained in the sulfates or sulfuric acid resulted only in partial increase of the antibiotic yield.