Comparative Study of the Extracellular Holocellulolytic Activity of Fusarium solani and Aspergillus sp. in Corn Stover

Abstract

Fungal holocellulases are interesting for their possible applications in the bioconversion of corn crop residues into molecules with technological significance. Holocellulase (xylanases and cellulases) production from Fusarium solani and Aspergillus sp. with corn stover as a carbon source was compared using a Box–Wilson design. The fungal holocellulase production was different in both fungi. For F. solani, the maximum endoxylanase and β-xylosidase activities were 14.15 U/mg and 0.75 U/mg at 84 h of fermentation on 350 g/L corn stover, while Aspergillus sp. was 5.90 U/mg and 0.03 U/mg, respectively, at 156 h and 1000 g/L corn stover. The production of holocellulases in both fungi was reduced with increasing carbon sources. The nitrogen source induced the holocellulases in Aspergillus sp., but not in F. solani. Interestingly, when verifying the optimal culture conditions, the production of endoxylanases by F. solani was higher when compared to the predicted value. With regard to the endoxylanase and β-xylosidase activities of Aspergillus sp., these were close to the predicted values. Based on the optimization model, F. solani and Aspergillus sp. produce an interesting holocellulolytic activity in a growth medium with corn stover as the only carbon source. The fermentation time and the amount of corn stover required to obtain maximum holocellulase production are possible advantages for Fusarium solani and Aspergillus sp., respectively.