Isolation of cellulose-degrading bacteria from termites microcerotermes sp.

Abstract

The main problem of using cellulose as a feedstock for direct bio-hydrogen production by a fermentative microorganism is the inefficiency of the process, because the hydrogenase enzyme cannot access the internal surface of the cellulose and convert it to hydrogen. To solve this problem, the accessibility of the hydrogenase enzyme was increase by converting cellulose to glucose by using a cellulose enzyme, which is generated from bacteria, before the fementation process. In this research, cellulose-producing bacteria were isolated from higher termites, Microcerotermes sp. Three effective strains of Bacillus subtilis (A 002, F 018, and M 015) were identified and studied for the specific celulose activities--endogulcanase, exoglucanase, and β-glucosidase—at 37℃ and pH 7.2. The results showed that strain F 018 had the highest specific exoglucanase activity and β-glucosidase activity; and strain M 015 had the highest specific endoglucanase activity. In addition, all three strains were also tested for their tolerance to the presence of the ionic liquid, 1-butyl-3-methylimidazolium chloride, or [BM1M]C1, which was used to enhance the accessibility of the cellulase enzyme in the pretreatment step. All strains were able to tolerate the [BM1M]C1 in the rage of 0.1 to 1.0 vol%.