# US 11,299,850 B2 · Converting lignocellulosic biomass to glucose using a low temperature sulfur dioxide pretreatment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,299,850 B2 - Document ID: US11299850B2 - Status: Granted - Kind: B2 - Application number: 16/761,180 - Filed: 2018-11-09 - Published: 2020-11-12 - Granted: 2022-04-12 - Earliest claimed: 2017-11-09 - Assignees: Iogen Corporation - Applicants: Iogen Corporation - Inventors: Brian Foody; Jeffrey S. Tolan; Daniel G. MacDonald; Kristin Martens; Natacha Leduc; Douglas A. MacKenzie - Web page: https://patentgrep.com/patent/US11299850B2 ## CPC - D21C 1/04: with acid reacting compounds - C08H 8/00: Macromolecular compounds derived from lignocellulosic materials {(pretreatment thereof B27N)} - C12P 7/10: substrate containing cellulosic material - C12P 19/02: Monosaccharides (2-ketogulonic acid C12P7/60) - C12P 19/14: produced by the action of a carbohydrase {(EC 3.2.x)}, e.g. by alpha-amylase {, e.g. by cellulase, hemicellulase} - D21C 3/06: sulfur dioxide; sulfurous acid; bisulfites {sulfites} - D21C 5/005: {Treatment of cellulose-containing material with microorganisms or enzymes} - C12P 2201/00: Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis - Y02E 50/10: Biofuels, e.g. bio-diesel - D21C: PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR - C08H: DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS (polysaccharides C08B; natural rubber C08C; natural resins or their derivatives C09F; bituminous materials C10) - C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)} - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A process for converting lignocellulosic biomass to glucose or ethanol includes subjecting the lignocellulosic biomass to a SO2 pretreatment within the temperature range 110° C.-150° C. Good glucose yields have been achieved when the SO2 pretreatment is conducted for more than 90 minutes and when the total amount of SO2 available is greater than 20 wt % based on dry weight of lignocellulosic biomass. ## Claims ### Claim 1 A method for converting lignocellulosic biomass to glucose comprising: pretreating the lignocellulosic biomass to provide a pretreated material, said pretreating comprising subjecting the lignocellulosic biomass to a SO2 pretreatment, said SO2 pretreatment comprising heating said lignocellulosic biomass with at least one of sulfur dioxide and sulfurous acid, said heating conducted between 110° C. and 150° C. for more than 90 minutes, said SO2 pretreatment conducted with a total amount of sulfur dioxide greater than 20 wt % based on dry weight of lignocellulosic biomass; and hydrolyzing at least 60% of the cellulose in the pretreated material to glucose, said hydrolyzing including adding enzyme to at least a solid fraction of the pretreated material, said enzyme including a cellulase. ### Claim 2 (depends on 1) The method according to claim 1, wherein said hydrolyzing provides a cellulose conversion of at least 80% within 72 hours. ### Claim 3 (depends on 2) The method according to claim 2, wherein said pretreating does not include heating the lignocellulosic biomass above 150° C. ### Claim 4 (depends on 2) The method according to claim 2, wherein said heating is conducted above 120° C. for more than 100 minutes. ### Claim 5 (depends on 4) The method according to claim 4, wherein said heating is conducted for more than 120 minutes. ### Claim 6 (depends on 5) The method according to claim 5, wherein said heating is conducted for more than 180 minutes. ### Claim 7 (depends on 2) The method according to claim 2, wherein said heating is conducted between 125° C. and 135° C. ### Claim 8 (depends on 1) The method according to claim 1, wherein the total amount of sulfur dioxide is greater than 25 wt % based on dry weight of lignocellulosic biomass. ### Claim 9 (depends on 1) The method according to claim 1, wherein the total amount of sulfur dioxide is greater than 30 wt % based on dry weight of lignocellulosic biomass. ### Claim 10 (depends on 1) The method according to claim 1, wherein the total amount of sulfur dioxide is greater than 40 wt % based on dry weight of lignocellulosic biomass. ### Claim 11 A method for converting lignocellulosic biomass to glucose comprising: pretreating the lignocellulosic biomass to provide a pretreated material, said pretreating comprising subjecting the lignocellulosic biomass to a SO2 pretreatment, said SO2 pretreatment comprising heating said lignocellulosic biomass with at least one of sulfur dioxide and sulfurous acid, said heating conducted between 110° C. and 150° C. for more than 90 minutes; and hydrolyzing at least 60% of the cellulose in the pretreated material to glucose, said hydrolyzing including adding enzyme to at least a solid fraction of the pretreated material, said enzyme including a cellulase, wherein said SO2 pretreatment is conducted with a total amount of sulfur dioxide greater than 70 wt % based on dry weight of lignocellulosic biomass. ### Claim 12 (depends on 6) The method according to claim 6, wherein the total amount of sulfur dioxide is between 20 wt % and 60 wt % based on dry weight of lignocellulosic biomass. ### Claim 13 (depends on 2) The method according to claim 2, wherein the lignocellulosic biomass comprises at least one of wheat straw and sugar cane bagasse. ### Claim 14 (depends on 2) The method according claim 2, wherein said adding enzyme comprises adding cellulase at a dosage of less than about 12 milligrams protein per gram of cellulose. ### Claim 15 (depends on 2) The method according to claim 2, wherein the total amount of sulfur dioxide is sufficient to provide an initial pH less than 1.25. ### Claim 16 (depends on 2) The method according to claim 2, wherein the total amount of sulfur dioxide is sufficient to provide an initial pH less than 1. ### Claim 17 A method for converting lignocellulosic biomass to glucose comprising: pretreating the lignocellulosic biomass to provide a pretreated material, said pretreating comprising subjecting the lignocellulosic biomass to a SO2 pretreatment, said SO2 pretreatment comprising heating said lignocellulosic biomass with at least one of sulfur dioxide and sulfurous acid, said heating conducted between 110° C. and 150° C. for more than 90 minutes, said SO2 pretreatment conducted with a total amount of sulfur dioxide greater than 20 wt % based on dry weight of lignocellulosic biomass; and hydrolyzing at least 60% of the cellulose in the pretreated material to glucose, said hydrolyzing including adding enzyme to at least a solid fraction of the pretreated material, said enzyme including a cellulase, wherein said hydrolyzing provides a cellulose conversion of at least 80% within 72 hours, and wherein said pretreating is conducted in the absence of added alkali. ### Claim 18 A method for converting lignocellulosic biomass to glucose comprising: pretreating the lignocellulosic biomass to provide a pretreated material, said pretreating comprising subjecting the lignocellulosic biomass to a SO2 ; pretreatment, said SO2 pretreatment comprising heating said lignocellulosic biomass with at least one of sulfur dioxide and sulfurous acid, said heating conducted between 110° C. and 150° C. for more than 90 minutes, said SO2 pretreatment conducted with a total amount of sulfur dioxide greater than 20 wt % based on dry weight of lignocellulosic biomass; and hydrolyzing at least 60% of the cellulose in the pretreated material to glucose, said hydrolyzing including adding enzyme to at least a solid fraction of the pretreated material, said enzyme including a cellulase, wherein said hydrolyzing provides a cellulose conversion of at least 80% within 72 hours, and wherein said pretreating is conducted in the absence of added organic solvent. ### Claim 19 (depends on 2) The method according to claim 2, wherein pretreating the lignocellulosic biomass to provide a pretreated material comprises pretreating lignocellulosic biomass having a consistency between 10 wt % and 40 wt %. ### Claim 20 (depends on 2) The method according to claim 2, comprising: subjecting the pretreated material to a solid/liquid separation that provides a liquid fraction and the solid fraction, and washing the solid fraction prior to said hydrolyzing. ### Claim 21 A process for the production of an alcohol from lignocellulosic biomass, said process comprising: feeding the lignocellulosic biomass into a pretreatment reactor; pretreating the lignocellulosic biomass in the pretreatment reactor to provide a pretreated material, said pretreating comprising heating the lignocellulosic biomass with at least one of sulfur dioxide and sulfurous acid between 110° C. and 150° C. for more than 100 minutes, where a total amount of sulfur dioxide is greater than 20 wt % based on dry weight of lignocellulosic biomass, where alkali is added in an amount in the range from 0 to 0.5 wt % based on dry weight of incoming lignocellulosic biomass and organic solvent is added in an amount in the range from 0 to 5 wt % based on dry weight of incoming lignocellulosic biomass; hydrolyzing at least 60% of the cellulose in the lignocellulosic biomass to glucose, said hydrolyzing including adding cellulase; fermenting the glucose to produce the alcohol; and recovering the alcohol.