The Biochemical Classification of Yeast Strains

Abstract

Examination by a bios-growth technique of 44 yeast cultures described as strains, vars. or races of Saccharomyces cerevisiae and S. carlsbergensis has shown that they may be further divided into 3 types: A[long dash]yeasts which give a crop that is low on the basal medium, is increased by thiamin, and further increased by vitamin B6; B[long dash]yeasts which give a crop that is high on the basal medium, is depressed by thiamin (not more than 50%), and is normal in the presence of thiamin and B6; C[long dash]yeasts which give a crop that is depressed more than half by thiamin but which give a high crop on addition of both thiamin and B6. A few cultures are described which, because of low crops on all media, can not be typed with certainty.