Extraction of Trehalose from Thermally-treated Bakers’ Yeast

Trehalose is a disaccharide of glucose mainly found in bakers’ yeast. We investigated the extraction conditions for trehalose from bakers’s yeast with an ethanol-water solution to increase the yield of trehalose from the yeast cells. A high extraction ratio of trehalose was obtained from thermally treated yeast, that is, from yeast cells treated by drying and heating, when compared with that from untreated raw yeast. This thermal had the effect of inactivating trehalase, which is a hydrolytic enzyme of trehalose, and accelerated the disruption of the yeast cells. These effects facilitated the extraction of trehalose within a short time at 25°C. When an ethanol-water solution of high concentration was used as the extraction solvent, the concentration of residual protein in the yeast extract was quite small. Especially in the case of dried yeast, the removal of protein from the yeast extract was not necessary for isolating and purifying trehalose after it had been extracted.