TEMPERATURE AND NUTRITIONAL REQUIREMENTS OF THERMOASCUS AURANTIACUS

The ascospores of Thermoascus aurantiacus were studied to determine their thermoduricity, temperature requirements for ascospore production and germination, and nutritional requirements for germination. Cardinal temperatures for growth were also ascertained. These ascospores were very thermoduric, germinating after a 2 h exposure to 85°C. The cardinal temperatures for growth were: minimum 30°C, optimum 47.5-52.5°C, maximum 60°C. Maximum ascospore production occurred between 7-8 days at temperatures between 35-40°C. The spores germinated in distilled water, but percent germination greatly increased when any of the nutrients tested were added.