Intensification of the softwood-to-ethanol processes – design of efficient enzymatic hydrolysis combined with mild steam pretreatment

Exploitation of softwood for bioethanol production is currently inefficient due to its recalcitrance that necessitates harsh pretreatment conditions. This results in degradation of hemicellulose to inhibitory compounds and reduced process yields. Here we target to simultaneously optimize steam-pretreatment (STEX) and enzymatic hydrolysis. The STEX severity will be reduced to retain hemicelluloses in the solids, but maintaining minimal enzyme accessibility, analyzed by advanced imaging techniques. To overcome increased substrate recalcitrance, caused by the formation of lignin-carbohydrate (LC) linkages, we will identify and characterize accessory enzymes (glucoronoyl esterases, glucoronidases, etherases, and LPMOs) that can degrade LC and other bonds contributing to recalcitrance. By tailoring specific enzyme cocktails and establishing advanced designs of enzymatic hydrolysis, this project will contribute to the intensification of the softwood-to-ethanol processes.