The accumulation of polyols by the yeast Debaryomyces hansenii in response to water stress

Abstract

Growth of the yeast Debaryomyces hansenii in 1% (w/v) glucose medium containing NaCl or KCI resulted in the accumulation of glycerol during the exponential phase of growth and arabinitol during the stationary phase. Similar results were obtained during growth of the yeast in 12.5% (w/v) glucose, 25% glucose, 25% fructose, and 1% glucose plus 25% polyethylene glycol M.W.200 (PEG 200). The results indicate that the intracellular glycerol concentration increases concomitantly with the solute concentration of the growth medium, while the accumulation of arabinitol is less pronounced. Growth of the yeast in media containing meso-erythritol or D-mannitol as carbon sources without or with 1 M NaCl resulted in the pronounced inhibition of arabinitol accumulation because of the intracellular accumulation of the exogenous polyols. Mannitol accumulated primarily during the stationary phase, while erythritol accumulation occurred primarily during the exponential phase. The erythritol concentration attained very high levels during growth in media containing 1 M NaCl and effectively inhibited the accumulation of glycerol.