Cellulase and Xylanase Production by Sugarcane Bagasse Mycobiota

Document Type : Original Research Articles.

Authors

1 Department of Botany and Microbiology, Faculty of Science, Assiut University, Assiut, Egypt

2 Moubasher Centre for Mycology, Assiut University, Egypt

Abstract

            Lignocelluloses of sugarcane represent a precious and cheap source for enzyme production by several fungal species. In the present study 25 samples of sugarcane bagasse were analyzed for their fungal content. The growing fungal strains were then screened for their abilities to produce cellulolytic and xylanolytic enzymes in solid and broth cultures. A total of 62 fungal species belonging to 31 genera were identified from the tested samples. The most prevalent genera were Aspergillus and Fusarium being isolated from 96% of the tested samples. Mucor, Penicillium and Talaromyces colonized 45% - 52% of bagasse samples.The most prevalent species were A. flavus, A. niger and F. oxysporum. Internal trans. Spacer (ITS) sequences of rDNA confirmed the identification of two new records (Ceratocystis adiposa, Phaeoacremonium viticola) in addition to Sarocladium kiliense, Stachybotrys chartarum and S. elegans. Cellulolytic activities were detected in solid cultures of 73.7% of fungal strains with the most active being Aspergillus tamarii, Exserohilum rostratum and S. chartarum. Xylanolytic activities were exhibited by59.8% of fungal strains and the active xylanase producers were A. niger, A. tamarii, A. tubingensis, C. adiposa and E. rostratum. Spectrophotometric measurements using dinitrosalicylic acid (DNS) reagents howed high cellulase concentration in broth cultures of S. chartarum followed by A. niger, C. adiposa and S. elegans (10.2- 52.0 IU/ml). The relative activity of fungal cellulase ranged from 0.2-1.7 IU/ml/min whereas the specific activity fluctuated between 2.471-14.590 IU/mg protein. Xylanase concentration, relative and specific activities were markedly high especially in cultures of A. niger (360.6 IU/ml, 32.0IU/ml/min. and 64.611 IU/mg protein, respectively).

Keywords

Main Subjects