A solid state fungal fermentation-based strategy for the hydrolysis of wheat straw

•A solid state fungal fermentation strategy converting wheat straw to hydrolysate.•A biological pre-treatment of wheat straw by culturing A. niger on wheat straw.•24.0±1.76U/g cellulase was produced using wheat straw as the main substrate.•The fungal extract was used to hydrolyze the fermented wheat straw.•19% higher hydrolysis efficiency using freshly-prepared fungal extract than Ctec2. This paper reports a solid-state fungal fermentation-based pre-treatment strategy to convert wheat straw into a fermentable hydrolysate. Aspergillus niger was firstly cultured on wheat straw for production of cellulolytic enzymes and then the wheat straw was hydrolyzed by the enzyme solution into a fermentable hydrolysate. The optimum moisture content and three wheat straw modification methods were explored to improve cellulase production. At a moisture content of 89.5%, 10.2±0.13U/g cellulase activity was obtained using dilute acid modified wheat straw. The addition of yeast extract (0.5% w/v) and minerals significantly improved the cellulase production, to 24.0±1.76U/g. The hydrolysis of the fermented wheat straw using the fungal culture filtrate or commercial cellulase Ctec2 was performed, resulting in 4.34 and 3.13g/L glucose respectively. It indicated that the fungal filtrate harvested from the fungal fermentation of wheat straw contained a more suitable enzyme mixture than the commercial cellulase.