Inhibition of Growth of Pellicle Forming Yeasts by a Killer Toxin Produced by a Debaryomyces hansenii KYT-1

Abstract

To prevent the growth of pellicle forming yeasts on fermented foods such as salted vegetables and miso, utilization of a killer toxin produced by a halotolerant killer yeast was investigated. The killer yeast KYT-1 was isolated from salted cucumber, and identified as Debaryomyces hansenii. The partially purified killer toxin produced by the strain retained its activity at temperatures below 15°C and at pH 3.0-5.5. To inhibit the growth of 1×10⁵/ml of each pellicle forming yeast, Hansenula anomala IFO 0569, D. hansenii IFO 0855 and D. hansenii S suspended in a seasoning solution for salted vegetable preparation, 1.8μg, 22μg and 7.4μg of the partially purified killer toxin was required, respectively.