EXPERIMENTAL CONDITIONS AFFECTING YEAST GROWTH

Abstract

The growth‐regulating effects of fermentation temperature, medium composition, addition of ergosterol and introduction of trace amounts of oxygen have been studied for six yeasts. This investigation demonstrates some important experimental details which frequently impair the reproducibility of small‐scale fermentations. The necessity of a balanced composition of growth media and control of the content of ergosterol and of trace amounts of oxygen is stressed. Variations in the yield obtained in defined media, with added minimum amounts of essential growth factors only, were in the range of 30–100% of optimum growth. Commercial yeast extracts tested seemed not to contain any compounds with a stimulating effect similar to that of ergosterol. 1971 The Institute of Brewing & Distilling