Chrysosporium keratinophilum IMI 338142 isolated from a waste site containing organopollutants was studied for its ability to produce extracellular proteases on glucose-gelatin medium. Fungus was observed to be a potent producer of such enzymes. Enzyme secretion was best at 15 days of incubation period at pH 8 and temperature 40 degrees C. Asparagine was repressive to protease expression. No relationship existed between the enzyme yield and increase in biomass. Exogenous sugars suppressed enzyme production in the descending order as follows: glucose > arabinose > maltose > mannose > fructose. The enzyme released showed the ability to decompose two keratin substrates tested. Buffalo skin was the most actively degraded substrate when exogenous glucose was absent. Presence of glucose suppressed both enzyme production and degradation of keratin. However, the rate of keratin degradation was independent of enzyme production.

The ability of Trichophyton simii HN 50, isolated from the Ghana Bird Sanctuary, Bharatpur, India, to produce extracellular keratinase was studied. Enzyme was produced on a keratin salt broth medium at pH7 and a temperature of 28 +/- 1 degree C. Enzyme secretion was best at 15 days of incubation. Asparagine and keratin were repressive to enzyme yield in comparison to gelatin. No relationship was observed between enzyme release and biomass sugars suppressed keratinase production in descending order as follows: glucose > mannose > maltose > arabinose > fructose. The enzyme showed ability to degrade all of the 3 keratin substrates. Buffalo skin was best degraded in the absence of glucose while chicken feathers were the least degraded in its presence.

Two soil isolates of Microsporum gypseum were studied for the production of extracellular proteases. Both the strains secreted protease on glucose-gelatin medium. The enzyme activity peaked on day 15 at 28°C. Asparagine repressed protease yield. Sugars caused catabolite repression of protease formation. Protease activities of both the isolates were significantly affected by incubation period, culture media and carbohydrates used. Both the strains grew on the skin bait and caused a gravimetrically measurable loss of the substrate. Despite less pronounced differences in the keratinase levels, great variations occured in the amount of keratin degraded by two isolates. Keratinase production as well as loss in substrate mass was better in glucose-lacking flasks than those containing the sugar. Although the rate of keratin degradation was independent of enzyme production, statistically positive correlations were recorded between loss in substrate mass: yielded dry mycelial weight and substrate degradation: keratinase levels.

Malbranchea gypsea IMI 338,168 isolated from the soils of Keoladeo National Park, Bharatpur was studied for its ability to produce exocellular proteases on glucose-gelatin medium at pH 7; 28 degrees C. The fungus was observed to be a potent producer of such enzymes. Protease production was optimal at 15 days of incubation. Asparagine was repressive to protease expression. No relationship existed between the amount of enzyme production and increase in biomass. Exogenous sugars suppressed enzyme production in descending order as follows: glucose > mannose > maltose > arabinose > fructose. The enzymes expressed showed the ability to degrade three keratinous substrates tested. Buffalo skin was the most actively degraded substrate when exogenous glucose was present, and was also the most resistant to degradation in the absence of glucose. The rate of keratin deterioration was independent of enzyme activity. Production of protease enzymes especially keratinases is ecologically important in a place like a National Park because such enzymes degrade keratinous detritus derived from mammals and birds. Accumulation of such materials can be a cause of pollution and can provide a breeding spot for various types of pathogens.