Genus/species (aliases): Cryptococcus laurentii; (Torulaspora laurentii; Torulopsis flavescens;Torulopsis flavescens;Cryptococcus flavescens; Rhodotorula laurentii; Torula flavescens; Torula laurentii);
Classification (ascomycete/basidiomycete): Basidiomycete
Morphology:
- Cell: Ovoid, 2-5 x 3-7 µm in size, encapsulated, budding yeast, gathering in chains of 3-4.
- Colony:
- Malt agar: Smooth, glossy, cream colored colonies, darkening to yellow-orange; In C. laurentii var. laurentii mycelium may grow, mostly below agar surface
- WL: Unknown
- Spore: In C. laurentii var. laurentii limited thick-walled ovoid – spherical chlamydospores formed, with hyphal growth in those that germinate. Less than 1% of spores germinate.
- Zygote: Teleomorph not identified
- Ascus: N/A (Basidiomcyete)
- Liquid Growth: flocculent
Physiological Traits:
Capable of degrading a large variety of plant structural compounds including xylanases, pectinases, cutinases, lipases, proteinases and laccases. Can also degrade hemicellulose into anionic extracellular polysaccharides.
Ecological Traits:
Found in most soils, especially arctic, prairie and tundra. Avian fecal matter is often a reservoir for the genus. It is a more dominant fungus on unripe grape berries and continues to be present when grapes are ripe (particularly in cooler climates).
Distinguishing Features:
Facultative alkaliphile; psychrophillic. Produces yeast killing factor.
Role in wine:
Can occur as native fungi on grape skin and also found in cellars and in corks; Rarely present in finished wine in significant quantities. In corks, it may be responsible for some odor/contamination problems; Recent studies indicate may be useful as a biocontrol method in vineyard management, particularly as regards to Botrytis cinerea – especially as it can degrade laccase.
Sensitivities:
- SO2: unknown
- Sorbate: unknown
- DMDC: unknown
- pH: unknown
- Acids: unknown
- Ethanol: Low tolerance
- Anaerobiosis: unknown
- Heat : Max is 30 degrees Celcius
References:
König H., G. Unden and J. Fröhlich. 2009. Biology of Microorganisms on Grapes, in Must, and in Wine. Springer, New York.