Isolation, identification and characterization of four cellulolytic actinomycetes and their cellulases

Abstract

Four highly cellulolytic actinomycetous isolates namely SG₁, SG₂, SG₃ and SS1 were isolated from soil samples and provisionally identified as Streptomyces almquistii, S. caeruleus , S. hirsutus and S. endus, respectively. All the isolates showed heavy growth and liquefaction at 50?C and pH 6.5 in Winsteads medium having 1.2% of CMC. The isolates were allowed to grow in Winsteads medium having Asparagine as a nitrogen source with different carbon sources for the maximum production of cellulases. The extracellular protein of the culture supernatant ranged from 1.14 ?g /ml (SG₁) to 879.39 ?g /ml (SG₃). The reducing sugar level of the culture supernatant ranged from 0.76 ?g /ml (SG₂) to 558.33 ?g /ml (SG₁). The highest CMC-ase activity (1431.81U/ml) was found with the crude enzyme of the strain SG₃. The highest FP-ase activity (1087.11 U/ml) and Avicelase activity (1287.87U/ml) were found with the crude enzyme of SS₁. To detrermine the optimum nitrogen sources, the isolates were allowed to grow in Winsteads medium having saw dust for SG₁ and SG₃, dry leaf for SS₁ and SG₂ as a carbon source with different nitrogen sources for the maximum production of cellulases. The extracellular protein of the culture supernatant ranged from 35.50 ?g /ml (SG₁) to 328.62 ?g /ml (SS₁) and the reducing sugar level of the culture supernatant ranged from 3.79 ?g /ml (SG₁) to 114.39 ?g /ml (SG₃). However the highest CMC-ase activity (1353.78 U/ml), and FP-ase activity (215.90 U/ml) were found with the crude enzyme of the strain SG₂ and Avicelase activity (356.06U/ml) was found with the crude enzyme of the isolate SS1

DOI: http://dx.doi.org/10.3329/cujbs.v6i1-2.17241

The Chittagong Univ. J. B. Sci.,Vol. 6(1&2):159-173, 2011