Determination of cellulolytic potentials of <i>Aspergillus</i> species isolated from central waste dump site of Nile University of Nigeria

Abstract

A large number of microorganisms are capable of degrading cellulose but only a few of these microorganisms produce significant quantities of enzymes capable of completely hydrolyzing cellulose. Fungi are the main cellulase-producing microorganisms. This study was aimed to determine the cellulolytic potentials of Aspergillus species isolated from the central waste dump site of Nile University of Nigeria. In this study, fungal species were isolated from soil samples obtained from waste dump site using pour plate technique. The isolates were characterized using cultural and morphological features as well as microscopic examination. Aspergillus flavus, Aspergillus niger, and Aspergillus terreus, which were isolated were further screened on carboxymethylcellulose agar for their ability to degrade cellulose. Screening of fungal isolates was performed by plate method. Cellulolytic fungi were evaluated after 5 days for the production of cellulolytic enzymes by staining with 1% Congo red. The diameter of clear zone on fungal plates, gave an approximate indication of cellulase activities. Aspergillus niger had a zone of clearing of 25.50 mm while Aspergillus flavus had 18.50 mm. Aspergillus terreus did not show any cellulolytic activity. Aspergillus niger had the highest occurrence rate of 50%. Aspergillus flavus and Aspergillus terreus both had 25% occurrence rate.