A NOVEL KILLER YEAST EFFECTIVE ON SCHIZOSACCHAROMYCES-POMBE

To control the extent of deacidification in wine making, we screened K luyveromyces strains by their activity to kill the fission yeast Schiz osaccharomyces pombe. Among Kluyveromyces IFO strains tested, K. walti i IFO 1666T was shown to have the desired activity. The killer spectru m of this strain was different from those of the other known killer ye asts. The activity was found in the culture medium and was lost by pro tease treatment. The activity was associated with the precipitate obta ined by an increase of ammonium sulfate concentration. The toxin was l arger than 10,000 daltons as judged by ultrafiltration.