LAUSR

Brewers' spent grain (BSG) is produced worldwide in millions of tons during the beer brewing process. Due to its high content of structural carbohydrates, BSG is a promising material for being valorised in biorefineries. In this study three process routes for producing itaconate from BSG hydrolysates are presented using the previously engineered smut fungi UstilagomaydisMB215Δcyp3ΔPria1::Petef as whole-cell biocatalyst. Using a fermentation medium based on BSG hydrolysate a yield of 0.38gIta/gSugar and a productivity of 0.11gIta/(L·h) were achieved. The addition of detoxified hydrothermal supernatant to the fermentation medium did not result in improved performance parameters but resulted in a decreased yield (0.29gIta/gSugar) and productivity (0.053 gIta/(L·h)). Simultaneous saccharification and fermentation with hydrothermal pretreated BSG is possible, although at lower rate. In summary, the valorisation of BSG in fungal fermentations might complement the end-of-life options of this industrial side product.