Study of the cellulase enzyme system of some native cellulolytic bacteria for degradation of lignocellulosic wastes

Cellulolytic bacteria with cellulase enzyme system play an important role in decomposing lignocellulose wastes and accelerating the composting process. For this purpose, a study was carried out on some native cellulolytic bacteria isolated from different sources in Soil and Water Research Institute. Twenty eight isolates were selected based on morphological characteristics and cellololytic test, in specific medium (B.H.M). Spot cultivation on B.H.M medium and observation of halo diameter as the cellulolytic characteristics of the isolates led to the separation of 12 isolates. The maximum and minimum diameter of a clear zone around the colony of MAL and HSE isolates were 31 and 8 millimeters respectively. Also the maximum and minimum proportion of clear zone diameter to colony were observed in TER and CPL isolates. The activity of endoglucanase, exoglucanase and betaglucosaidase among 12 isolates showed that the least amount of endoglucanase was belong to SAD (0.17 U.ml-1) and the most one was NTL (2.55 U.ml-1) isolates. The maximum activity of betaglucosidase in NTT isolate was 0.31 U.ml-1 and the maximum exoglucanase enzyme activity was belong to HPN isolate (0.35 U.ml-1)and minimum was belong to BSB isolate (0.18 U.ml-1). Analysis of variance showed that the differences between the isolates with the highest and lowest triple cellulase activity was significant (especially endoglucanase (at one percent statistic level but was not significant between some isolates. There was a direct relation between cellulase activity and the enzyme compound. NTT isolate showed the highest activity of beta-glucosidase enzymes and it was the second and the third in terms of endoglucanase and exoglucanase production, respectively. It had the highest activity of three enzymes (3.21 unit) and identified and registered as Bacillus methyltrophicus.