STUDIES ON THE INFLUENCE OF MINUTE AMOUNTS OF FATTY ACIDS IN BACTERIOLOGICAL CULTURE MEDIA ON BACTERIAL GROWTH (I)

GROWTH-ACCELERATING ACTION OF TRACE AMOUNTS OF FATTY ACIDS IN VITAMIN-FREE CASEIN ACID-HYDROLYSATE ON STREPTOCOCCUS HEMOLYTICUS STRAIN S-8

Abstract

1. The growth of a strain of Streptococcus hemolyticus in semisynthetic media was reduced by using a ether-treated acid-hydrolysate of vitamin-free casein (vitamin-free Casamino acids-Difco) as the nitrogen source, but growth was recovered by the addition of the ether-extract of this hydrolysate.
2. It was determined that vitamin-free Casamino acids (Difco) contains 0.01-0.001% of stearic acid.
3. Stearic acid exerted an accelerative effect on Streptococcus hemolyticus strain S-8, most remarkably, while palmitic and arachidic acids affected to some extent. No accelerative action was observed on oleic, linoleic and linolenic acid, but inhibitory action was exerted by all of them in higher concentrations.