Debaromyces hansenii

Genus/species (aliases): Debaromyces hansenii (Candida fomata, anamorph; Saccharomyces hansenii, Torulaspora hansenii, Debaromyces tyrocola, Castellania castellanii

Classification: Ascomycetel, teleomorph

Morphology:

  • Cell: Spherical or short-ellipsoidal occurring singly, in pairs or short chains
  • Colony:
  • Malt agar: grayish white to yellow, soft, either shiny or dull, smooth, and may be wrinkled
  • WL: white colonies
  • Spore: Spherical and warty, generally one, occasionally two, spores per ascus
  • Zygote: Conjugation between mother cell and bud
  • Ascus: fusion of two cells through protuberances developed from cross walls
  • Liquid Growth: Sediments, rings, and smooth or wrinkled dry pellicle may form

 

Physiological Traits:

  • Fermentation: very weak or absent
  • Assimilation: Lactose, Galactose, Sucrose, Maltose, Mellibiose, Cellobiose, Trehalose, Raffinose, Soluble starch, D-Xylose, L-Arabinose, Ribitol, Mannitol, Succinate, Lactate, Citrate.  End products include β-glucosidases; no assimilation of nitrate; Variable use of other compounds as sole N source; No growth in vitamin-free medium, requires biotin
  • Growth: 37 and 40 C, none at 42 C and above
  • Growth Sensitivities: 10% NaCL: +; variable resistance to cycloheximide, high glucose and higher salt levels

Ecological Traits:

Widespread, isolated from the ocean, various cheeses, grape surfaces

Distinguishing Features:

Never strongly ferments glucose, high salinity tolerance (24%), frost resistant (cryotolerant).

Role in wine:

Normal grape/fermentation flora. Produces high levels of β-glucosidases, which creates more monoterpenol in the wine, affecting sensory results.  Sensory effects include higher terpenol flavors, especially linalool.

Sensitivities:

  • SO2: No
  • Sorbate­­­­­: unknown
  • DMDC: unknown
  • pH: No (unless extreme)
  • Acids: No
  • Ethanol: No
  • Anaerobiosis: yes
  • Heat : yes

References:

  • Kreger van Rij NJ, Veenhuis M. Electron microscopy of ascus formation in the yeast debaryomyces hansenii. 1975 J Gen Microbiol. (2):256–264.
  • Yanai, T.; Sato, M. Isolation and properties of β-glucosidase produced by Debaryomyces hansenii and its application in winemaking. 1999. Am. J. Enol. 50:3:231-235.