Biomass sorghum as a novel substrate in solid-state fermentation for the production of hemicellulases and cellulases by Aspergillus niger and A. fumigatus.

Abstract

We investigated the role of carbon and nitrogen sources in the production of cellulase and hemicellulase by Aspergillus strains. The strains Aspergillus niger SCBM1 and Aspergillus fumigatus SCBM6 were cultivated under solid-state fermentation (SSF), with biomass sorghum (BS) and wheat bran (WB) as lignocellulosic substrates, in different proportions, along with variable nitrogen sources. The best SSF condition for the induction of such enzymes was observed employing A. niger SCBM1 in BS supplemented with peptone; maximum production levels were achieved as follows: 72h of fermentation for xylanase and exoglucanase (300·07 and 30·64Ug-1 respectively), 120h for β-glucosidase and endoglucanase (54·90 and 41·47Ug-1 respectively) and 144h for β-xylosidase (64·88Ug-1 ). This work demonstrated the viability of the use of BS for the production of hemi- and cellulolytic enzymes; the high concentration of celluloses in BS could be associated with the significant production of cellulases, mainly exoglucanase. This is the first study which presents the promising use of biomass sorghum (genetically modified sorghum to increase its biomass content) as an alternative carbon source for the production of enzymes by SSF.