EN
In present paper the cellulolityc activity of soil strain Micromonospora rubra was investigated. The strain was incubated in Dubois medium amended with 1% filter paper, carboxymethyl- cellulose or microcrystalline Avicel cellulose as the single carbon source. The above cultures were incubated at 28"C on rotary shaker for 10 days. The biosynthesis of cellulolytic enzymes (FP-ase, CMC-ase) was determined using colorimetric method suggested by International Biochemical Committee. The activity of cellulolytic enzymes was measured in 2 days intervals in proper supernatants. The effect of pH on FP-ase and CMC-ase activity was determined using supernatant obtained by centrifugation of 10 days old culture of investigated Mi- cromonospora strain in medium amended with CMC. The investigated strain M. rubra was able to produce both FP-ase and CMC-ase. The intensity of above enzymes depended from kind of cellulosic substrate and incubation time of culture. The highest activity of both enzymes was obtained using CMC as a carbon source. The investigated M. rubra strain produced only trace amounts of FP-ase and CMC-ase in medium amended with filter paper. Optimum pH of both enzymes was 6.0.