Influence of carbon source on production of a heat stable protease from Thermomonospora fusca YX

Summary Thermomonospora fusca YX produced a very active heat stable protease when incubated in media containing cellulose as the substrate. Cultures grown on Solka-floc generated the highest amount of protease whereas the protease was produced at significantly lower levels when T. fusca YX was grown on cellobiose or glucose. Negligible growth or protease production was observed when protein was used as a carbon source. The production of the protease did not appear to be constitutive. While rapid growth was observed on either cellobiose or glucose, protease levels were at least two to fourfold lower than for the T. fusca YX cultures grown on Solka-floc wich generated 33% less cell mass. Protease production was four times lower in cultures which employed casein hydrolysate (tryptone) or xylan as carbon sources than for cellulose.