Characterization of the pretreatment liquor of biomass from the perennial grass, Eulaliopsis binata, for the production of dissolving pulp

To test a biorefinery concept, the non-wood biomass of Eulaliopsis binata was treated with dilute acid prior to dissolving pulp production at 160 °C for 30 min. The pretreatment liquor (PL) contained 42.04 g/L sugars, of which 81.46% was xylose and only 2.91% was glucose. Furfural and hydroxymethylfurfural in PL were 0.37% and 0.06%, respectively. Chemical or enzymatic hydrolysis of carbohydrates could be omitted when producing bioethanol with PL because 87.32% of the total sugars were in the form of monosaccharides. Membrane filtration with a molecular-weight cut-off of 100 Da was employed to concentrate the sugars and a concentration of 170.49 g/L was achieved. A method of zero release of the PL is proposed, which consists of ethanol production from the concentrated PL and recycling the permeate stream into the pretreatment process.