The occurrence of killer characters in yeasts

Abstract

Strains of the genera Saccharomyces, Saccharomycodes, Schizosaccharomyces, Hanseniaspora, Kluyveromyces, Pichia, Kloeckera, and Torulopsis were examined for killer, sensitive, neutral, and killer–sensitive characteristics against a killer strain (NCYC738) and a sensitive strain (NYCC1006) of Saccharomyces cerevisiae. Thirty-one Saccharomyces cerevisiae strains out of 782 screened were able to kill the sensitive test strain; 707 appeared to be sensitive and 44 neutral. A high frequency of killer phenotypes (71.4%) was found in Hansenula anomala var. anomala strains. No killer strains were present in the remaining 17 species considered.