Genus/species (aliases): Issatchenkia terricola (Pichia terricola, Saccharomyces terricolus)
Classification: Ascomycete, teleomorph
- Cell: Reproduces by budding; ovoidal to elongate in shape, occur singly or in pairs; simple pseudohyphae may be formed.
- Colony: Malt agar: Growth is butyrous with tannish cream oval colonies.
- Spore: Spheriodal spores with a roughened appearance due to protuberances from the cell wall.
- Zygote: Unconjugated diploid cell; isolates are typically heterothallic
- Ascus: Can be either conjugated or unconjugated. House one to four ascospores and are persistent. Two spores per ascus is most typical
- Liquid Growth: Dry, climbing pellicles formed that may be moderate to heavy depending upon the strain.
- Fermentation: Glucose
- Assimilation: Succinate, Citrate, Ethanol, Glycerol. No assimilation of nitrate; will use ethylamine, lysine and cadaverine as sole N source; no growth in vitamin-free medium, requires thiamin.
- Growth: 37, 40 C: variable
- Growth Sensitivities: Some strains resistant to high glucose; not resistant to cycloheximide.
Found in soils, sea water, spoiled fruit and fruit juices.
Diazonium Blue test yields positive results. Unlike many other Issatchenkia species I. terricola will not grow on vitamin free medium.
Role in wine:
Often acts as a spoilage yeast in fruit juices; can be part of grape juice native flora.
Sensitivities: See 'Physiological Traits" and is heat sensitive.
Chavan P., et al. Natural yeast flora of different varieties of grapes used for wine making in India. Food Microbiology 2009 Dec:26(8):801-8.