Patent ID: 7649086

Claim:
An integrated method for the treatment of plant material, comprising: (a) in a first stage extraction process, contacting the plant material with an aqueous ethanol solution at a first elevated temperature and at a first elevated pressure for a period of time sufficient to produce treated plant material solids and a liquid mixture comprising ethanol, ethanol-soluble lignin and water; (b) separating the treated plant material solids from the liquid mixture; (c) recovering the ethanol-soluble lignin front the liquid mixture withdrawn from the first stage extraction process; (d) in a second stage extraction process, contacting the treated plant material solids separated from the first stage extraction process with water at a second elevated temperature and at a second elevated pressure for a period of time sufficient to solubilize hemicellulose sugars from the treated plant material and produce an aqueous product stream containing water soluble sugars and a resulting plant pulp material; and (e) separating the aqueous product stream containing water soluble sugars from the resulting plant pulp material.