[Effect of vitamins on the biosynthesis of nisin by a Streptococcus lactis culture].

Milk is the natural medium for Str. lactis, strain MSU. It is known that in winter and spring the growth and acid production by acidolactic streptococci are decreased. This is due, in particular, to the absence of vitamins in winter and spring milk. A number of vitamins present in complex natural products, such as tomato juice, milk and casein hydrolysates, beaf extract, etc. was studied with respect to their effect on the synthesis of nisin. The organic complexes had a positive effect on the growth of Str. lactis and the antibiotic biosynthesis. However, Str. lactis, strain MSU did not intensify the nisin synthesis on addition of vitamins to the spring skin milk. Possibly, lactis, strain MSU was of low sensitivity to the season of changes in milk.