| dc.description.abstract | The aim of this research was to screen Indonesian proteolitic Streptomyces isolates and to characterize partially their proteases . Three isolates of Streptomyces which are: SLW 8-1, C1-3, and 45I -3 have been chosen in this experiment because of the large clear zone around the colony in NA media containing 1 %skim milk. Extracellular protease which have been produced, will be characterized further using NB media containing 1 %skim milk. The optimum time for harvesting crude extract protease of SLW 8-1 isolate is in the 7th day by the optimum activity in pH 9 and temperature of 80 ºC. The optimum time for harvesting crude extract protease of C1-3 isol ate is in the 7th day by the optimum activity in pH 9 and temperature of 40 ºC. The optimum time for harvesting crude extract protease from 45I-3 isolate is in the 4th day with the optimum activity in pH 7.5 and temperature 50º C. Extracellular prot ease of those three isolates were known have keratinolytic activities after tested by 1% chicken feather powder in their optimum pH and temperature. The three isolates have higher protease activity in hydrolyzing 1% chicken feather powder substrate comparing wit h hydrolyzing 1% casein. The increased of protease activity by using 1 % chicken feather powder for the three isolates are 67.40% (SLW 8-1), 345.41 % (C1-3), and 19.36 % (45I-3). | id |
