Isolation and characterization of cellulolytic Bacillus licheniformis from compost
Eight cellulose degrading bacteria were isolated from compost and were identified as Bacillus licheniformis by 16S rRNA sequencing. Among the eight isolates, Bacillus licheniformis B4, B7 and B8 showed the highest cellulase activity. B. licheniformis B4 and B8 showed the maximum cellulase activity during the stationary phase of growth; but for B7, the maximum activity of cellulase was observed during the log phase. Reducing sugar released in the media, increased with increasing cellulase activity for all the three isolates. Significant correlation was observed between cellulase activity and protein content. The crude cellulase from B7 strain showed activity towards carboxymethyl cellulose and filter paper, but there was no detectable activity towards p-nitrophenyl- β-Dglucopyranoside (PNPG). The crude cellulase of B. licheniformis B7 exhibited maximum activity at 50°C and at pH 6 to 7.
Keywords: Bacillus licheniformis, 16S rRNA, cellulase, reducing sugar, compost, viscosity