DOI: 10.36347/sajb.2014.v02i12.004

Pages: 863-870

A total of three Aspergillus species were isolated from decaying palm press cake. These organisms were screened on Dox medium for mannanase production. All three isolates grew on the medium, thus indicating that the organisms were able to utilise the locust bean gum present in the medium. The Aspergillus isolates were used to produce mannanase enzyme under submerged fermentation. Cocoyam powder was used as the sole carbon source in the Dox medium and it served as a substitute to locust bean gum. The final pH values of the three isolates were in the acidic range. Aspergillus tamari had a growth rate of 0.17g/ml, while the Aspergillus niger had a growth rate of 0.25g/ml. The Aspergillus niger crude enzyme solution had a higher protein content of 0.83mg/ml when compared to Aspergillus flavus (0.75mg/ml) and Aspergillus tamari (0.73mg/ml). Aspergillus niger also produced a higher amount of mannanase (0.3489U/ml), when compared to Aspergillus flavus (0.1830U/ml) and tamari (0.1546U/ml) respectively.