Aktivitas Selulolitik dan Karakterisasi Aktinomiset Asal Tanah Gambut

Abstract

In the peat soil, various groups of microorganism decomposing peat are present, including actinomycetes. Eighty isolates of actinomycetes were isolated from peat soil samples. Congo red clearing zone assay was used for qualitative observation of cellulolytic activity and it was found that 20 isolates showed positive results with clear zone around the colony. Cellulase production was assayed by measuring the amount of glucose liberated in μmol mL-1 min-1 by using the dinitrosalicylic acid assay method. Among the twenty isolates, the isolates 15 and 42 were found to have relatively higher cellulase enzyme activity both qualitatively and quantitatively compared with the others. Maximum production of cellulase by isolate 15 and 42 were detected on day-30 and day-15, respectively, and showed CMCase, Avicel, and FPase activities which indicated a synergy of endoglucanase and exoglucanase in the cellulase enzyme system of the tested isolates. Furthermore, morphological characteristics of 15 and 42 isolates were compared to other reference strains, belongs to Streptomyces species. The analysis of nucleotida of 16S rRNA showed that isolate 15 were closely related to the Streptomyces diastaticus with maximum identity 98% and isolate 42 were closely related to the Streptomyces exfoliatus with maximum identity 94%. Meanwhile phylogenetic analysis showed that isolate 15 homologous to isolate 42 with a bootstrap value of 100%. This study provided important basic information on potential cellulolytic from actinomycetes group.