# US 8,569,018 B2 · Simplified method for digestion of cellulosic biomass

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- Number: US 8,569,018 B2
- Document ID: US8569018B2
- Status: Granted
- Kind: B2
- Application number: 12/933,865
- Filed: 2009-03-31
- Published: 2011-01-27
- Granted: 2013-10-29
- Earliest claimed: 2008-04-01
- Assignees: Biomass Conversions, LLC
- Applicants: Seiji Hata
- Inventors: Seiji Hata
- Web page: https://patentgrep.com/patent/US8569018B2

## CPC

- C12P 7/10: substrate containing cellulosic material
- C08B 1/00: Preparatory treatment of cellulose for making derivatives thereof {, e.g. pre-treatment, pre-soaking, activation}
- C08H 8/00: Macromolecular compounds derived from lignocellulosic materials {(pretreatment thereof B27N)}
- 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}
- C13K 1/02: obtained by saccharification of cellulosic materials (manufacture of fodder A23K10/32)
- D21C 3/003: {with organic compounds (D21C3/20 and D21C3/222 take precedence)}
- D21C 9/1036: {Use of compounds accelerating or improving the efficiency of the processes}
- C12P 2201/00: Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
- Y02E 50/10: Biofuels, e.g. bio-diesel
- 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)}
- C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21)
- C08H: DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS (polysaccharides C08B; natural rubber C08C; natural resins or their derivatives C09F; bituminous materials C10)
- C13K: SACCHARIDES OBTAINED FROM NATURAL SOURCES OR BY HYDROLYSIS OF NATURALLY OCCURRING DISACCHARIDES, OLIGOSACCHARIDES OR POLYSACCHARIDES (chemically synthesised sugars or sugar derivatives C07H; polysaccharides, e.g. starch, derivatives thereof C08B; malt C12C; fermentation or enzyme-using processes for preparing compounds containing saccharide radicals C12P19/00; production of sucrose C13B)
- D21C: PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The inventive process converts cellulosic biomass into a gel-like state that is readily hydrolyzed by appropriate enzymes. First the biomass is mechanically reduced in size. The biomass is then mixed and kneaded with an aqueous solution of a hydrophilic polymer that acts as a conditioning agent or as a co-solvent. During mixing the cellulose (and hemicellulose) in the biomass swells and becomes hydrated forming a viscous gel-like material. The processed material can then be thinned through the addition of water whereupon hydrolytic enzymes are mixed into the material and rapid hydrolysis into free sugars takes place. Dextrins are effective hydrophilic polymers for conditioning biomass. Polyvinyl alcohol is a particularly effective conditioning agent for use with biomass when converted into a viscous gel by adding borate ions.

## Claims

### Claim 1

A process for converting cellulosic biomass into a readily hydrolyzable mixture comprising the steps of:
forming a polyvinyl alcohol gel by crosslinking an aqueous solution of polyvinyl alcohol;
combining cellulosic biomass particles with the crosslinked polyvinyl alcohol gel to form a gel-biomass mixture; and
mixing-kneading the gel-biomass mixture to convert the gel-biomass mixture into swelled and hydrated biomass in a gel-like state wherein the cellulose is amenable to enzymatic hydrolysis.

### Claim 2 (depends on 1)

The process of claim 1, wherein the polyvinyl alcohol gel is formed by adding borate ions to the aqueous solution of polyvinyl alcohol.

### Claim 3 (depends on 1)

The process of claim 1, wherein the biomass particles have average diameters of less than about 100 micrometers.

### Claim 4 (depends on 3)

The process of claim 3, wherein the biomass particles have average diameters of about 20-70 micrometers.

### Claim 5 (depends on 1)

The process according to claim 1 where liquefaction and saccharification enzymes are added to the swelled and hydrated biomass to liquefy and hydrolyze it into free sugars.

### Claim 6 (depends on 1)

The process of claim 1, further comprising a step of heating the gel-biomass mixture to at least about 70° C. during the step of mixing-kneading.

### Claim 7 (depends on 1)

The process of claim 1 wherein the biomass particles constitute about 40% by weight of the gel-biomass mixture.

### Claim 8 (depends on 1)

The process according to claim 1 further comprising a step of periodically adding water to reduce the viscosity of the gel-biomass mixture.

### Claim 9 (depends on 1)

The process according to claim 1 further comprising a step of periodically adding additional biomass particles to the gel-biomass mixture.