Effect of Aeration on the Cytochrome Systems of the Resting Cells of Brewers' Yeast

Abstract

BREWERS' yeasts have a lower respiration and, usually, a higher fermentation than bakers' yeasts. The absorption spectrum of their cytochrome differs from the typical four-banded spectrum of bakers' yeast¹ in showing only two distinct bands in the visible region². By increasing the oxygen supply during growth, their absorption spectrum was changed into that of ‘bakers’ yeasts'³. Similar changes have also been noticed in Aspergillus oryzæ⁴. Since all these experiments were conducted under the conditions which allow cell proliferation, it was naturally considered that the observed changes were due to a selection of certain cells, the multiplication of which was favoured by aeration.