# US 7,341,848 B2 · Isomaltose synthase-knockout microorganism belonging eumycota

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- Number: US 7,341,848 B2
- Document ID: US7341848B2
- Status: Granted
- Kind: B2
- Application number: 10/532,064
- Filed: 2003-10-20
- Published: 2006-10-19
- Granted: 2008-03-11
- Earliest claimed: 2002-10-23
- Assignees: Amano Enzyme Inc.
- Inventors: Kanako Suzuki; Norihiro Tsukagoshi
- Web page: https://patentgrep.com/patent/US7341848B2

## CPC

- C12N 9/2451: {acting on alpha-1,6-glucosidic bonds}
- C12N 9/2408: {acting on alpha -1,4-glucosidic bonds}
- C12N 15/80: for fungi
- C12Y 204/01139: Maltose synthase (2.4.1.139)
- C12Y 302/0102: Alpha-glucosidase (3.2.1.20)
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)
- C12Y: ENZYMES

## Abstract

It is intended to provide a host microorganism whereby the expression of a gene encoding a target protein can be effectively elevated in the case of transferring the gene. It is also intended to provide a transformant whereby a target protein can be produced at a high efficiency. It is further intended to provide a production process whereby a target protein can be produced at a high productivity. A microorganism which belongs to Eumycota and lacks the major isomaltose synthase. A gene encoding a target protein is transferred into the microorganism to give a transformant. Then the transformant is cultured under conditions allowing the expression of the transferred gene to thereby produce the protein.

## Claims

### Claim 1

A transformant obtained by introducing a foreign gene into a microorganism which belongs to Aspergillus which lacks an α-glucosidase B gene, wherein the foreign gene comprises a structural gene and a promoter promoting a transription of the structural gene, the promoter is a promoter whose transcription activity is induced by isomaltose, and the promoter is a promoter of α-amylase gene, glucoamylase gene, or α-gloucosidase gene of Aspergillus.

### Claim 2

A transformant obtained by introducing a foreign gene into Aspergillus nidulans which lacks an α-glucosidase B gene, wherein the foreign gene comprises a structural gene and a promoter promoting a transcription of the structural gene, the promoter is a promoter whose transcription activity is induced by isomaltose, and the promoter is a promoter of α-amylase gene, glucoamylase gene, or α-glucosidase gene of Aspergillus.

### Claim 3

A transformant obtained by introducing a foreign gene into a microorganism which belongs to Aspergillus which lacks an α-glucosidase B gene, wherein the foreign gene comprises a structural gene and a modified promoter obtained by inserting a first DNA fragment containing CCAATNNNNNN (first base sequence: SEQ ID NO: 1) and a second DNA fragment CGGNNNNNNNNNGG (second base sequence: SEQ ID NO: 2) into a promoter capable of functioning in Aspergillus, said modified promoter is a promoter whose transcription activity is induced by isomaltose.

### Claim 4 (depends on 1)

A method of producing proteins, the method comprising:
a step of culturing the transformant according to claim 1 under the conditions capable of allowing the foreign gene to express; and
a step of collecting the produced proteins.