African Journal of Biotechnology Vol. 2 (6), pp. 140–146, June 2003

Bacillus pumilus BpCRI 6, a promising candidate for cellulase production under conditions of catabolite repression

Kotchoni O.S.^1*†, Shonukan O.O.¹ and Gachomo W.E.²

¹Department of Microbiology, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.

²Institute for Plant Diseases, University of Bonn, Nussallee 9, D-53115 Germany.

*Corresponding author; Kotchoni O.S.,Tel: + 49-228-739581, Fax: + 49-228-732689, E-mail: kotchoni@uni-bonn.de

†Current Address: Department of Plant Molecular Biology, Institute of Botany, University of Bonn, Kirchallee 1, D-53115 Bonn, Germany.

Accepted 16 May 2003

Cellulose degrading organisms have been used for the conversion of cellulolytic materials into soluble sugars or solvents in several biotechnological and industrial applications. In this report, a mutant of Bacillus pumilus was obtained after chemical mutagenesis and screened for cellulase production. This mutant named BpCRI 6 was selected for its ability to produce cellulase under catabolite repression. Cellulase yield by BpCRI 6 was four times higher than that of the wild type under optimum growth conditions (pH 6.5, 25°C and Ca²⁺ 1mM). In shaking flask cultures, production of cellulase  by the wild type was completely repressed in the presence of 25 mM glucose, while BpCRI 6 strain still exhibited a residual cellulase production of 80 and 40% at 25 mM and 40 mM of glucose concentrations respectively. The mutant strain is stable and grows rapidly in liquid and solid media. Under conditions of catabolite repression (40 mM of glucose), the production of cellulase by this mutant is particularly significant when compared to Trichoderma reesei a well-known cellulase producer, which is under control of end-product inhibition. This is the first report of a successful catabolite repression insensitivity of cellulase production by a mutant of B. pumilus.