Accumulation and Role of Trehalose in Torulaspora delbrueckii No.3110

We isolated an alcohol-fermenting yeast, Torulaspora delbrueckii No. 3110, which was more salttolerant than Saccharomyces cerevisiae IFO 0224 as measured by alcohol fermentation. Strain No. 3110 produced 5.5 wt% of ethanol in a medium containing 1M NaCl in 4 days, but strain IFO 0224 produced a mere 0.8%.Strain No. 3110 constitutively accumulated intracellular trehalose (10–17% of dry cell weight). A mutant, Tl, did not accumulate trehalose. Tl synthesized and assimilated less trehalose and was less salt-tolerant than No. 3110. These results suggest that metabolism of trehalose is important for the expression of salt tolerance.