[Antioxidant stabilization of the antifoaming agents used in the fermentation process].

Oils used as antifoaming agents in fermentation are subjected to oxidation to form various products, such as aldehydes, carboxylic acids, peroxides, etc. The negative effect of such products on biosynthesis of chlortetracycline by strains VUA 84 and Iz 22/VUPL of Str. aureofaciens was recorded. The level of the oil oxidation was characterized by the contents of peroxides and epihydrinaldehydes. The Kreiss qualitative test was modified for quantitative estimation of epihydrinalydehydes. The oil antifoaming agents characterized by the routine parameters used in determination of oil quality, such as acid number, saponification number and iodine number. In the control experiments lard and soybeen oil were oxidized by air at a temperature of 100 degrees C without an antioxidant (2,6-ditetrabutyl-4-methylphenol). The oil antifoaming agents such as soybeen oil and lard were tested in biosynthesis of chlortetracycline carried out in flasks and pilot plant 750 1 apparatus. Antioxidant 4K, an alkylphenol antioxidant, in a 2% concentration proved to be effective for prevention of oxidation and nontoxic for the culture.