Cellulase-Producing Bacteria Isolated from Mufindi Paper Mill Industrial Effluent, Iringa Tanzania

Abstract

Effluent and effluent-contaminated soil samples collected from Mufindi Paper Mill Limited, Iringa Tanzania were investigated for the presence of cellulolytic bacteria. The components of cellulase are endoglucanase, exoglucanase and β-glucosidase and these are very important for complete hydrolysis of cellulose to glucose monomers. Isolates were grown on nutrient agar and screened for cellulolytic activity on carboxymethylcellulose (CMC) agar plates using Gram’s iodine solution. Cellulases activities; endoglucanase, exoglucanase and β-glucosidase were assayed using CMC, avicel and cellobiose substrates, respectively by dinitrosalicyclic acid method. Out of 17 cellulolytic isolates obtained, crude enzyme extracts of only five isolates expressed all cellulases activities, the highest activity being on cellobiose followed by CMC and least on avicel. The maximum endoglucanase (0.0701 ± 0.010 U/ml), exoglucanase (0.0081 ± 0.001 U/ml) and β-glucosidase (0.0738 ± 0.002 U/ml) activities from submerged fermentation culture were observed from isolate 8, 1 and 12, respectively. Based on 16S rRNA sequences analyses, three isolates were identified as Pararheinheimera mesophila, Bacillus cereus and Bacillus flexus. The other two isolates were identified as Bacillus megaterium.

Keywords: Cellulose; Endoglucanase; Exoglucanase; β-glucosidase; 16S rRNA