# US 8,785,165 B2 · Single pH process for starch liquefaction and saccharification for high-density glucose syrups

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- Number: US 8,785,165 B2
- Document ID: US8785165B2
- Status: Granted
- Kind: B2
- Application number: 14/113,557
- Filed: 2012-04-27
- Published: 2014-03-27
- Granted: 2014-07-22
- Earliest claimed: 2011-04-29
- Assignees: Danisco US Inc.
- Applicants: Sung Ho Lee; Jayarama K. Shetty; Paula Johanna Maria Teunissen
- Inventors: Sung Ho Lee; Jayarama K. Shetty; Paula Johanna Maria Teunissen
- Web page: https://patentgrep.com/patent/US8785165B2

## CPC

- C12P 19/20: produced by the action of an exo-1,4 alpha-glucosidase, e.g. dextrose
- C12N 9/2428: {Glucan 1,4-alpha-glucosidase (3.2.1.3), i.e. glucoamylase}
- 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)}
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Embodiments of the present disclosure relate to a process for producing downstream products, such as high-density glucose syrups and high-glucose fermentation feedstock, from a starch-containing substrate without a pH adjustment before the saccharification step. The saccharification is effectively catalyzed by a glucoamylase at a pH in the range of 5.2 to 5.6.

## Claims

### Claim 1

A method of processing a starch comprising saccharification of a starch substrate to glucose in the presence of a glucoamylase without a pH adjustment, wherein saccharification is performed at pH 5.2 to 5.6 and at a temperature in the range of about 58° C. to about 62° C., wherein the glucoamylase is selected from the group consisting of a parent Humicola grisea glucoamylase (HgGA) comprising SEQ ID NO: 3 and a variant thereof, wherein the variant has at least 99% identity to the parent glucoamylase.

### Claim 2 (depends on 1)

The method of claim 1, wherein saccharification is performed in the presence of a pullulanase.

### Claim 3 (depends on 1)

The method of claim 1, wherein the variant glucoamylase has at least one amino acid modification compared to the parent glucoamylase.

### Claim 4 (depends on 1)

The method of claim 1, wherein the glucoamylase is HgGA having amino acid sequence of SEQ ID NO: 3.

### Claim 5 (depends on 1)

The method of claim 1, wherein the glucoamylase is produced in a Trichoderma reesei host cell.

### Claim 6 (depends on 1)

The method of claim 1, wherein the glucoamylase is added at a dose of at least about 0.15 GAU per gram of dry substance starch.

### Claim 7 (depends on 1)

The method of claim 1, wherein the glucoamylase is added at a dose of at least about 0.20 GAU per gram of dry substance starch.

### Claim 8 (depends on 1)

The method of claim 1, wherein saccharification is carried out at pH 5.35 to 5.5.

### Claim 9 (depends on 1)

The method of claim 1, wherein the starch substrate is liquefied starch.

### Claim 10 (depends on 1)

The method of claim 1, wherein saccharification achieves a DP1 concentration of at least 95% at about 70 hours.

### Claim 11 (depends on 1)

The method of claim 1, wherein the starch substrate is about 30% to about 50% dry solids (DS).

### Claim 12 (depends on 11)

The method of claim 11, wherein the starch substrate is about 30% to about 35% dry solids (DS).

### Claim 13 (depends on 1)

The method of claim 1, wherein the starch substrate is granular starch.

### Claim 14 (depends on 13)

The method of claim 13, wherein saccharification achieves a DP1 concentration of at least 95% at about 28 hours.

### Claim 15 (depends on 14)

The method of claim 14, wherein the starch solubility of the starch substrate is at least 90%.

### Claim 16 (depends on 13)

The method of claim 13, wherein saccharification achieves a DP1 concentration of at least 96% at about 50 hours.

### Claim 17 (depends on 16)

The method of claim 16, wherein the starch solubility of the starch substrate is at least 97%.

### Claim 18 (depends on 16)

The method of claim 16, wherein the higher sugar content is below 1%.

### Claim 19 (depends on 13)

The method of claim 13, wherein the starch substrate is about 28% dry solids (DS).