Role of oxygen in the induction of fermentation in the obligately psychrophilic yeast Leucosporidium stokesii.

Leucosporidium stokesii, an obligately psychrophilic yeast, metabolizes glucose during the initial stages of aerobic growth by aerobic respiration. During later stages of growth and in the presence of excess glucose and limiting oxygen the organism develops a fermentative-type metabolism. Rates of respiration on the other hand remain relatively constant. The change in metabolism occurs only at temperatures which support growth of the organism and does not occur at 25 degrees C. Resting cells prepared from young glucose-grown cultures can be induced to ferment glucose. The induction process occurs only in the presence of glucose and is inhibited by actidione.