Two-stage dilute-acid and organic-solvent lignocellulosic pretreatment for enhanced bioprocessing

[Display omitted] •A two stage treatment to fractionate different components of biomass is proposed.•Process uses reduced enzyme loadings and results in increased hydrolysis rates.•Near complete conversion of glucan content is achieved with 2 stage process.•48h can be taken off the time of hydrolysis and reach similar conversions. A two stage pretreatment approach for biomass is developed in the current work in which dilute acid (DA) pretreatment is followed by a solvent based pretreatment (N-methyl morpholine N oxide – NMMO). When the combined pretreatment (DAWNT) is applied to sugarcane bagasse and corn stover, the rates of hydrolysis and overall yields (>90%) are seen to dramatically improve and under certain conditions 48h can be taken off the time of hydrolysis with the additional NMMO step to reach similar conversions. DAWNT shows a 2-fold increase in characteristic rates and also fractionates different components of biomass – DA treatment removes the hemicellulose while the remaining cellulose is broken down by enzymatic hydrolysis after NMMO treatment to simple sugars. The remaining residual solid is high purity lignin. Future work will focus on developing a full scale economic analysis of DAWNT for use in biomass fractionation.