CALCIUM IN FLOCCULENCE OF<i>SACCHAROMYCES CEREVISIAE</i>

Abstract

A quantitative method was adopted for measuring flocculation intensity of yeast photometrically. In three strongly flocculent strains of Saccharomyces cerevisiae examined with this method, flocculation intensity depended on ionic strength of the medium as well as on Ca concentration, and was maximum at about 0·01 ionic strength. At this optimum ionic strength, when free Ca concentration was varied in stabilized complexing systems, a transition occurred at about 10−8 m Ca between flocculent and nonflocculent states. At higher Ca concentrations, flocculation intensity was nearly constant. The observed transition is at much lower Ca levels than other effects noted in the literature.