Development of respiration in yeast grown anaerobically on different carbon sources

Abstract

The weight of cells obtained when yeast was grown anaerobically was the same when anyone of 3 sugars (glucose, fructose, and galactose) was used as substrate. Yeast grown anaerobically in galactose retained its ability to respire. The activity of cytochromec oxidase in these cells was about 1/3 of that of the aerobic inoculum. In nongrowing cells, casein hydrolysate added to the medium caused the development of a more rapid respiration with time when galactose or glucose was the substrate but not when lactate, pyruvate, or ethanol was the substrate. Casein hydrolysate stimulated the consumption of galactose and the production of CO2 by yeast grown anaerobically on galactose. Yeast grown anaerobically on galactose could respire immediately on glucose, fructose, galactose, or pyruvate, but yeast grown anaerobically on fructose oxidized none of these substrates immediately but could adapt to oxidizing glucose or fructose.