Some characteristics of a growth stimulant in corn steep liquor for Lactobacillus casei.

In a previous report by Kennedy and Speck (1955), it was shown that the addition of corn steep liquor to milk stimulated the growth of several species of lactic acid bacteria. Additional studies (Kennedy et al., 1955) have shown the stimulatory factor to be different from other stimulatory factors reported for the lactic acid organisms. These investigators also observed that corn steep appeared to shorten the lag growth phase of the lactic acid organisms. It has been reported by Malmgren and Heden (1947) that in microrganisms moderate amounts of nucleic acids have been formed by the end of the lag phase in growth, and in the logarithmic phase the nucleic acid content is at its maximum. Hoffman and Paveek (1952) observed that uridine, a compound found in corn steep, stimulated the early growth of Streptococcus faecalis. Since corn steep contains nucleic acids, the possibility eists that the stimulatory factor(s) is a nucleic acid derivative. By the use of paper chromatography, bioautography and qualitative analysis, a stimulatory substance has been isolated from corn steep which gave characteristics of a nucleoside. The results of these studies are reported in this paper.