# US 5,346,817 A · Method for producing a microbial polyester

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- Number: US 5,346,817 A
- Document ID: US5346817A
- Status: Granted
- Kind: A
- Application number: 07/903,021
- Filed: 1992-06-23
- Granted: 1994-09-13
- Earliest claimed: 1991-06-24
- Assignees: Asahi Kasei Kogyo Kabushiki Kaisha
- Inventors: Minoru Akiyama; Yoshiharu Doi
- Web page: https://patentgrep.com/patent/US5346817A

## CPC

- C12N 1/205: Bacterial isolates
- C12P 7/625: Polyesters of hydroxy carboxylic acids
- C12R 2001/05: Alcaligenes
- Y10S 435/829: Alcaligenes
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)
- 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)}
- C12R: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES C12C - C12Q, RELATING TO MICROORGANISMS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

An improved method for producing a microbial polyester comprising 3-hydroxybutyrate monomer units is disclosed, in which a strain belonging to the genus Alcaligenes is cultured in a liquid medium containing a carbon source selected from specific long chain fatty acids and derivatives thereof. The produced microbial polyester is useful in plastics and polymers which are free from environmental pollution problems, and in implanting materials and drug carriers, recovery of which is not necessary.

## Claims

### Claim 1

A method for producing a microbial polyester comprising D-(-)-3-hydroxybutyrate monomer units, which comprises the steps of:
(1) providing a liquid medium containing at least one essential carbon source selected from the group consisting of fatty acids each having 10 to 22 carbon atoms and derivatives thereof;
(2) culturing a strain belonging to the species Alcaligenes lipolytica, said strain producing a microbial polyester comprising D-(-)-3-hydroxybutyrate monomer units and being negative to both a nitrate reduction and a denitrification reaction, in said liquid medium, thereby obtaining a cultured broth containing a microbial polyester comprising D-(-)-3-hydroxybutyrate monomer units; and
(3) isolating said microbial polyester from said cultured broth.

### Claim 2 (depends on 1)

The method according to claim 1, wherein said microbial polyester is a homopolymer of a D-(-)-3-hydroxybutyrate monomer or a copolymer of a D-(-)-3-hydroxybutyrate monomer and a D-(-)-3-hydroxyv-alerate monomer.

### Claim 3 (depends on 1)

The method according to claim 1, wherein each of said fatty acids has 11 to 18 carbon atoms.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the number of carbon atoms of each fatty acid is odd to thereby produce a copolymer of a D-(-)-3-hydroxybutyrate monomer and D-(-)-3-hydroxyvalerate monomer.

### Claim 5 (depends on 2)

The method according to claim 2, wherein the number of carbon atoms of each fatty acid is even.

### Claim 6 (depends on 5)

The method according to claim 5, wherein said liquid medium further contains at least one additional carbon source selected from the group consisting of compounds of the formula:
CH.sub.3 (CH.sub.2).sub.2n-1 X (I)
wherein X represents a group of the formula ##STR2## in which R represents a hydroxyl group, a methoxy group or an ethoxy group, or a group of the formula --CH.sub.2 --OR', in which R' represents a hydrogen atom, an acetyl group or a propionyl group, and n is an integer of from 1 to 4.

### Claim 7 (depends on 1)

The method according to claim 1, wherein said strain utilizes at least one member selected from the group consisting of a fatty acid, a fat and an oil each having at least 10 carbon atoms.