Production of xylanases from brewery spent grain and subsequent application into the spent solid residue after treatment with renewable ionic liquids for the production of sugars-containing solutions

This article develops a three-steps biorefining process for the complete fractionation of brewery spent grain (BSG). First, BSG was used as substrate for solid-state fermentations in horizontal drum bioreactors with different amounts of Aspergillus brasiliensis to produce enzymatic cocktails, mainly xylanases. Second, the spent solid residue recovered under the lower inoculum concentration was treated with the cholinium glycinate ionic liquids (ILs) to obtain a carbohydrate-rich material with lower lignin content. Pretreatment with ILs has been postulated to improve the enzymatic saccharification of lignocellulosic biomass to achieve higher amounts of sugars. In addition, scanning electron microscopy allowed visualizing somemicrofibrils and pores, that could facilitate the diffusion of enzymes inside the lignocellulosic matrix. Finally, the enzymatic cocktail, containing mainly xylanases, was successfully applied to achieve saccharification values of 54.37 ± 2.34% for xylan. The results improved those obtained using commercial enzyme preparations Ultraflo L® and Shearzyme® 500 L, showing the clear benefits of the whole integrated process proposed.Graphical abstract

Source: Process Biochemistry - June 12, 2019 Category: Biochemistry Source Type: research