The invention relates to a process for treating lignocellulosic biomass by means of an acidic liquor in order to produce “second-generation” (2G) sugary liquors. These sugary liquors may be used to produce other products via a biochemical pathway (e.g. alcohols such as ethanol, butanol or other molecules, for example solvents such as acetone, etc.). This process comprises analysis of the liquid streams withdrawn during the process and adjustment of the composition of the impregnation liquor so as to keep the acidic power of said streams constant.

A process for converting lignocellulosic biomass to glucose or ethanol includes subjecting the lignocellulosic biomass to a SO.sub.2 pretreatment within the temperature range 110° C.-150° C. Good glucose yields have been achieved when the SO.sub.2 pretreatment is conducted for more than 90 minutes and when the total amount of SO.sub.2 available is greater than 20 wt % based on dry weight of lignocellulosic biomass.

A process for the production of cellulose, lignocellulosic sugars, lignosulfonate, and ethanol from lignocellulosic biomass. The process comprises steaming, pretreatment, chemical recovery, saccharification, and optionally fermentation. The pretreatment conditions use only sulfur dioxide and water, simultaneously resulting in high glucan conversion to glucose at low enzyme charges, high recovery of hemicellulose-derived monomeric sugars, high lignosulfonate yield, and the absence of lignin precipitates. High-yield production of ethanol through fermentation can be obtained using this process.

The invention is directed to compositions and processes concerning efficient downstream processing of products derived from organic acids pretreatment of plant materials.

The invention is directed to compositions and processes concerning efficient downstream processing of products derived from organic acids pretreatment of plant materials.

The invention is directed to compositions and processes concerning efficient downstream processing of products derived from organic acids pretreatment of plant materials.

The invention is directed to compositions and processes concerning efficient downstream processing of products derived from organic acids pretreatment of plant materials.

A process for producing an organic aliphatic product (such as butanol) from lignocellulosic biomass is provided, comprising: (a) fractionating lignocellulosic biomass in the presence of a solvent for lignin, a hydrolysis catalyst, and water, to produce a liquor containing hemicellulose, cellulose-rich solids, and lignin; (b) washing the cellulose-rich solids and separating the cellulose-rich solids from the liquor; (c) enzymatically hydrolyzing the cellulose-rich solids to generate a hydrolysate comprising glucose; (d) detoxifying the hydrolysate by neutralizing the hydrolysate, removing insoluble solids, and removing or oxidizing residual hydrolysis catalyst, thereby generating a purified hydrolysate; (e) fermenting the purified hydrolysate using a suitable microorganism to produce a dilute organic aliphatic product, wherein the microorganism is recycled with a membrane; (f) extracting the dilute organic aliphatic product into a water-immiscible extractant, to generate an intermediate material; and (g) distilling the intermediate material to generate a concentrated organic aliphatic product.

Some variations provide a method of enzymatically converting biomass-derived cellulose to glucose, comprising exposing the biomass-derived cellulose to (i) cellulase enzymes, to hydrolyze the cellulose to glucose; and (ii) an external sulfur-containing compound, to deter bacterial and/or yeast contamination during cellulose hydrolysis. In some embodiments, the sulfur-containing compound includes sulfur dioxide or lignosulfonates. When the sulfur-containing compound includes lignosulfonates, the lignosulfonates may also function as an enzyme surfactant to assist hydrolysis, in addition to deterring bacterial and/or yeast growth/contamination. This method may be applied to cellulose-rich solids obtained from the AVAP® fractionation process, the GREEN POWER+® pretreatment process, or any other source of cellulose-rich solids.

The present invention also provides for a method to deconstruct a biomass: the method comprising: (a) introducing a solvent to a biomass to dissolve at least part of solid biomass in the solvent, wherein the solvent comprises (i) a metal salt, and (ii) an ionic liquid (IL) or deep eutectic solvent (DES), or mixture thereof, to form a solubilized biomass mixture; (b) optionally introducing an enzyme and/or a microbe to the composition such that the enzyme and/or microbe produce a biofuel and/or chemical compound from the solubilized biomass; and, (c) optionally the biofuel and/or chemical compound is separated from the composition.