The Anaerobic Metabolism of Glucose and Fructose by Saccharomyces bailii

Publisher Website
Google Scholar
Abstract
Summary: In contrast to most yeasts, which ferment glucose more rapidly than fructose, Saccharomyces bailii ferments fructose first, then glucose. Thus, in a medium containing fructose and glucose, diauxic growth results. Cells of S. bailii that were grown on fructose were unable to ferment glucose when suspended in a glucose-containing buffer solution. Fructose-grown cells were cryptic for glucose fermentation but contained the enzymes for glucose metabolism. When suspended for 2 h in a growth medium containing glucose, fructose-grown cells acquired the ability to ferment glucose, due to the synthesis of a carrier protein. This induction was prevented by cycloheximide. In S. bailii, fructose was transported into the cells by a constitutive carrier system that was insensitive to uranyl ions. The inducible glucose carrier system was completely inhibited by 10−4 M-uranyl ions. If subsequent metabolism of hexoses was inhibited by iodoacetic acid, the uptake of hexoses could be measured by the increase in their intracellular concentrations. Fructose-grown cells took up only fructose whereas glucose-grown cells possessed an inducible glucose carrier and uptake of both glucose and fructose was observed. A model is proposed to explain the sequential fermentation of fructose and glucose in S. bailii.

This publication has 0 references indexed in Scilit: