Some biological effects of volatile metabolites from cultures of Saccharomyces cerevisiae Meyen ex Hansen.

The gas mixtures from cultures of Saccharomyces cerevisiue inhibited growth and sporulation of Aspergillus niger and germination of seeds of Lepidium sativum. In test conditions seven volatile organic metabolites in the culture gases were identified by gas-liquid chromatography (GLC) as acetaldehyde, ethyl acetate, ethanol, n-propanol, isobutanoi, and a mixture of isopentanols (I part 2-methyl-butan-1-01 to 2 parts 3-methyl-butan-1-01); changes in the concentrations of C 0 2 and O2 were also measured. Pure samples of each of these components were tested at the concentrations found in the culture gases in order to identify the inhibitory substances. Inhibition of growth of Aspergillus niger could be produced by these culture gas concentrations of acetaldehyde and of ethanol. Inhibition by this concentration of COz was just significant in these tests. The effect on sporulation could be produced by the COZY but not by these concentrations of any of the other identified components. The effect of Lepidium sativum seed germination could be produced by these culture gas concentrations of ethanol and of 3-methyl-butan-1-01 to a lesser extent. Slight effects were also observed with a lowered O2 concentration and with a raised C 0 2 concentration but not with the other constituents.