Rhodotorula glutinis

Genus/species (aliases): Rhodotorula glutinis (Cryptococcus glutinis; Cryptococcus bronchialis, Rhodotorula bronchialis ,Rhodotorula rubra, Saccharomyces glutinis, Saccharomyces roseus, Torulopsis glutinis)

 

Classification: Basidiomycete, anamorph

Morphology:

  • Cell: Reproduction by budding; ovoid to ellipsoidal or elongate; some strains produce pseudohyphae.
  • Colony: Malt agar: rapid growing, smooth, glistening or dull, sometimes.
  • roughened. Color- cream to pink, coral red, orange colonies.
  • Spore: some strains form asexual pigmented teliospores.
  • Zygote: NA
  • Ascus: NA
  • Liquid Growth: pink to orange colored ring and sediment.

Physiological Traits:

  • Fermentation: Absent
  • Assimilation: Glucose, Sucrose, Trehalose, Succinate; variable use of: Galactose, Maltose, Cellobiose, Sorbose, Melezitose, Raffinose, Starch, Arabinose, Ribose, Rhamnose, D-Xylose, Ribitol, Xylitol, Glucitol, Mannitol, Galactitol, Gluconate, Salicin, Arbutin, Lactate, Citrate, Ethanol; assimilates nitrate and nitrite; variable use of ethylamine, lysine and cadaverine as sole N source; variable for growth in vitamin-free medium, some strains require thiamin
  • Growth 37 C: variable
  • Growth Sensitivities: some strains resistant to cycloheximide; some strains able to grow in high NaCl and high glucose

R. glutinis secretes the enzyme alpha-L arabinofuranosidase. It prefers an initial pH of about 5.2, a temperature of 28C and is an aerobic yeast. Characteristic pink/red colonies are produced on SDA (Sabouraud’s Dextrose Agar) media. R. glutinis is unable to ferment carbohydrates but is able to scavenge nitrogenous compounds from its environment remarkably well.

Ecological Traits:

Found in air, soil, lakes, ocean water and dairy products

Distinguishing Features:

Closely related to Cryptococcus and Candida. Distinguished from Cryptococcus by its inability to assimilate inositol and fromCandida by pink to red colonies.

Role in wine:

R. glutinis is not properly classified as a wine-related yeast. It is  a common laboratory contaminant (likely because of its presence in air), and thus it is noted in some wine texts, but has no role in winemaking.

Sensitivities:

See Physiological traits

References:

  • Boulton, R. et al. 1996. Principles and Practices of Winemaking. Chapman and Hall, New York.
  • Lanzafame, M. 2001. Rhodotorula glutinis related meningitis. Journal of Clinical Microbiology. 39(1): 410-411.

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