The Change of Glycolytic Intermediates in myo-Inositol-Deficient Saccharomyces carlsbergensis

Abstract

The changes of metabolites in the culture medium, the intracellular concentrations of glycolytic intermediates in the actively fermenting yeast cells and the related enzyme activities were studied to establish a possible mechanism of acetoin accumulation in Saccharomyces carlsbergensis due to myo-inositol deficiency.
During the cultivation of the yeast for five days, the amounts of acetaldehyde and pyruvic acid were found to be low compared with that of acetoin but siginficantly large amount of acetaldehyde was detected in the myo-inositol deficieient culure medium.
Specific activity of alcohol dehydrogenase extracted from the myc-inositol deficient yeasts cultured for 24 hours, was higher than that from the normal ones and more ethanol was found in the deficient cell extract when glucose was used as the substrate. Though the activity of pyruvate decarboxylase of the deficient yeasts was low, they produced 2-3 times as much acetaldehyde and 10-18 times as much acetoin as the normal yeasts by fermentation of glucose for 15 or 30 minutes. The accumulation of acetaldehyde is considred to be a main cause for the abnormal acetoin production in the deficient Saccharomyces carlsbergensis.