Factors influencing the utilisation of L-malate by yeasts

The utilisation of L-malate and the effect of glucose concentration on malate utilisation under semi-anaerobic conditions were investigated in three yeasts unable to grow on malate as sole carbon source (Saccharomyces cerevisiae, Schizosaccharomyces malidevorans, Zygosaccharomyces bailii) and two yeasts able to utilise the TCA cycle intermediate as sole carbon source (Pichia stipitis and Pachysolen tannophilus). Utilisation of malate by both Schiz. malidevorans and Z. bailii was reduced at high and low levels of glucose. In the absence of glucose, P. stipitis and Pa. tannophilus utilised malate rapidly; however, their utilisation was drastically reduced in the presence of glucose, suggesting that malate utilisation is under catabolite repression.