Liquid / Liquid Separation of Lignocellulosic Biomass to Produce Sugar Syrups and Lignin Fractions

摘要

A process for production of C5 and C6 sugar enriched syrups from lignocellulosic biomass and fermentation products therefrom is described. A lignocellulosic biomass is treated with acetic acid with washing thereof with a C1-C2 acid-miscible organic solvent, (e.g., ethyl acetate). A soluble hemicellulose and lignin enriched fraction is obtained separately from a cellulose pulp enriched fraction and lignin is removed from the soluble hemicellulose fraction. The soluble hemicellulose and lignin enriched fraction is subjected to liquid/liquid separation to obtain an aqueous phase enriched in C5 sugars and C6 sugars and reduced in content of acetic acid. The syrup is suitable for fermentation. The process also produces fractions of organic-insoluble lignin, organic-soluble lignin, and acetate salts.

主权项

1. A method of processing lignocellulosic biomass, comprising:
a. contacting a lignocellulosic biomass with a first amount of acetic acid; b. heating the contacted lignocellulosic biomass to a temperature and for a time sufficient to hydrolytically release a first portion of hemicellulose and lignin, forming a hydrolysate liquid and an acylated lignocellulose cake; c. separating the acylated lignocellulosic cake from the hydrolysate liquid; d. contacting the acylated lignocellulose cake with a second amount of the acetic acid to wash hemicellulose and lignin from the acylated lignocellulosic cake and separating an acid wash liquid from the acid washed acylated lignocellulosic cake; e. contacting the acid washed acylated lignocellulose cake with a first amount of a C1-C2 acid-miscible organic solvent to wash the acetic acid, hemicellulose and lignin from the acid washed acylated lignocellulosic cake and recovering the C1-C2 acid-miscible solvent wash liquid separate from the solvent washed acylated lignocellulose cake; f. combining the solvent wash liquid with at least one of the hydrolysate and the acid wash liquid forming an acidic organic solvent extract; g. condensing the acidic organic solvent extract forming a concentrated hemicellulose and lignin aqueous phase enriched with hemicellulose and lignin; and, h. adding to the concentrated hemicellulose and lignin aqueous phase a second amount of the C1-C2 acid-miscible organic solvent sufficient to induce phase partitioning into a first phase comprising a washed heavy aqueous phase enriched in C5 and C6 sugars and organic-insoluble lignin and a second phase comprising an organic supernatant phase comprising organic-soluble lignin, acetate salts, C1-C2 acid-miscible solvent, and acetic acid.