[Variability of the proteolytic activity in the thermotolerant actinomycete, Thermoactinomyces vulgaris].

: The thermophilic culture of Thermoactinomyces vulgaris PA-11-4a, like other actinomycetes, is characterized by a high variability. This strain produces protease. The property is maintained if spores are incubated in sterilized distilled water for 30 min after lyophilization and then inoculated onto a solid medium (Petri plates) in order to select small dark-coloured colonies. The activity of protease does not decrease if such colonies are grown on solid media during seven months at 4 degrees C.