Production of cellulases and xylanases in solid-state fermentation by different strains of Aspergillus niger using sugarcane bagasse and brewery spent grain

Abstract

The objective of this study was to evaluate the effect of sugarcane bagasse (SCB) and brewery spent grain (BSG) on xylanase and cellulase enzymes production using different strains: Aspergillus niger CECT 2700, A. niger CECT 2915 and A. niger ITV-01 growing up in solid-state fermentation (SSF). Both lignocellulosic residues were previously subjected to three pretreatments: alkaline, boiling water, and autoclave. The maximum cellulase activity was 6.23 U/g of a dry substrate (gds) using A. niger CECT 2700 and BSG pretreated with boiling water. Further, the highest xylanase activity (1400.80 U/gds) was obtained using BSG pretreated in autoclave with A. niger CECT 2700 strain. Also, the highest cellulases and xylanases production was recorded on day 5 with a microbial load of 5 × 106 spores/gds. Finally, the enzymatic extract from A. niger CECT 2700 reached maximum saccharification in alkaline pretreated SCB of 68.52 and 78.66 % of glucan and xylan, respectively. This investigation showed the feasibility to obtain an enzymatic extract with xylanase and cellulase activity using low-cost substrates such as SCB and BSG.