ISOLATION AND DISTRIBUTION OF STREPTOMYCES POPULATIONS WITH HEAT-RESISTANT COLLAGENOLYTIC ACTIVITY FROM 2 PROTEIN-RICH AREAS IN BULGARIAN SOILS

Two sites in Northeastern of Bulgaria were investigated as a source of Streptomyces populations to screen for production of heat-resistant c ollagenase. The distribution and diversity of collagenolytic activity in Streptomyces populations from protein-rich residue were studied. Co llagenolytic activity was found in 14% of the 350 tested strains. Poor collagenase producers generally dominated (70%). Highly active collag enase producers were rarely found (12%) and they were mainly from Albu s and Roseus groups. The isolated Streptomyces cultures developed a co nstitutive collagenase activity. Two promising, highly active, produce rs of heat-resistant collagenase were selected and identified as Strep tomyces candidus 91 and S. cremeus 3. The investigated Streptomyces co llagenases were active over a broad range of temperature (40-80 degree s C) and a narrow range of pH values (6.5-8.5), with optima at 40 degr ees C and pH 7.5.