A 13C comparative nuclear magnetic resonance study of organic solute production and excretion by the yeasts Hansenula anomala and Saccharomyces cerevisiae in saline media

Glycerol, arabitol and trehalose were the principle solutes detected in cellular extracts of Hansenula anomala, using natural-abundance 13C nuclear magnetic resonance spectroscopy. Only the two polyols accumulated in response to increased salinity, glycerol increase being far greater. Arabitol content also increased with culture age, independently of the presence or absence of salt and in line with the evolution of trehalose content. Glycerol retention potential was 15 times greater for Hansenula than for Saccharomyces cerevisiae. The former displayed the specific property of increasing this capacity in high salt concentrations. Under such conditions its growth was associated with a limited increase in glucose consumption per unit biomass, relative to S. cerevisiae, the salt-sensitive reference yeast. In addition, a polysaccharide, the chemical nature of which was not further characterized, was detected exclusively in the external medium of Hansenula growing in the presence of salt.