POLYHYDRIC ALCOHOL PRODUCTION BY OSMOPHILIC YEASTS: EFFECT OF OXYGEN TENSION AND INORGANIC PHOSPHATE CONCENTRATION

Abstract

A study was made of the effects of oxygen tension and inorganic phosphate concentration on the production of glycerol, arabitol, and ethanol by a strain of osmophilic yeast. Increasing the oxygen tension increased the yields of glycerol and arabitol and decreased the yield of ethanol, while increasing the concentration of inorganic phosphate had the opposite effect.The changes in yields of products with increasing phosphate concentration were most pronounced at a partial pressure of oxygen of 280 mm. of mercury. At lower oxygen tensions the yields of polyols were low and the yield of ethanol was high at all concentrations of phosphate, while at very high oxygen tensions the opposite effect was observed. When the ethanol yield was high, the respiratory quotient was also high. These results are discussed in relation to the oxidative phosphate-lack theory of the Pasteur effect.