Investigation of the cellulases production by Aspergillus niger NSPR002 in different cultivation conditions

Résumé

This study investigated the influence of different process parameters on cellulases production by Aspergillus niger NSPR002 under submerged fermentation. The selected fungal isolates coded Aspergillus niger NSPR001, A. niger NSPR002 and Fusarium vertilloides NSPR003 were screened for the production of cellulases by submerged cultivation in liquid mineral salt medium in which carboxymethylcellulose (CMC) had been added as the sole carbon source. Cultivation conditions investigated include variation of the carbon and nitrogen sources, pH, incubation temperature and time of incubation. All the tested fungal isolates proved to be producers of cellulases with differences in the rate of biosynthesis. Of all the fungal isolates screened, Aspergillus niger NSPR002 displayed the highest cellulases activity of 0.122μmol/min/mL. Several types of agricultural wastes (pawpaw peels, potato peels and cassava peels) were tested as substitutes of CMC in medium for cellulases production by Aspergillus niger NSPR002. Among tested agricultural byproducts, pawpaw peels at a concentration of 5% was found to be the most effective carbon source. Out of the organic nitrogen sources tested, locust beans meal was observed to yield maximum cellulases activity (0.361μmol/min/mL). The optimum pH, temperature and incubation time were 4.5, 32oC and 72 h, respectively.