Copolyester and process for producing the same

Claim 2

A copolyester comprising 3-hydroxybutyrate units and units selected from: (1) 3-hydroxyvalerate units and 5-hydroxyvalerate units; (2) 4-hydroxybutyrate units; and (3) 4-hydroxybutyrate units and 3-hydroxyvalerate units; the intrinsic viscosity of the copolyester when measured in chloroform at 30°C being from 0.4 to 10.0 dl/g.

Claim 3

A copolyester according to claim 1 which comprises from 2 to 50 mol% of 3-hydroxybutyrate units, from 3 to 95 mol% of 3-hydroxyvalerate units and from 3 to 90 mol% of 5-hydroxyvalerate units.

Claim 4

A copolyester according to claim 1 which comprises from 40 to 97 mol% of 3-hydroxybutyrate units and from 3 to 60 mol% of 4-hydroxybutyrate units.

Claim 5

A copolyester according to claim 1 which comprises from 10 to 90 mol% of 3-hydroxybutyrate units, from 3 to 60 mol% of 4-hydroxybutyrate units and from 5 to 87 mol% of 3-hydroxyvalerate units.

Claim 6

A process for producing a copolyester as defined in claim 1, which process comprises: propagating a microorganism having the ability to producing poly-3-hydroxybutyrate, and culturing the microorganism in a limited source of nitrogen and/or phosphorus and in the preence of a carbon source to form and accumulate the copolyester in the microorganism, the carbon source being selected from: (i) a compound of formula (I): (CH₂X¹CH₂CH₂CH₂COO)n¹Y¹      (I) wherein X¹ represents a hydroxyl group or a halogen atom, which may be identical or different to any other X¹ group if n¹ is greater than 1, n¹ represents an integer of from 1 to 4 and Y¹ represents a hydrogen atom or a uni- to tetravalent metal atom; (ii) a compound of formula (II): (CH₂X²CH₂CH₂COO)n²Y²      (II) wherein X² represents a hydroxyl group or a halogen atom, which may be identical or different to any other X² group if n² is greater than 1, n² represents an integer of from 1 to 4 and Y² represents a hydrogen atom or a uni- to tetravalent metal atom; (iii) a compound of formula (II) as defined above and a compound of formula (III): (CH₂X³CHX⁴CH₂CH₂COO)n³Y³      (III) wherein X³ represents a hydrogen atom, a halogen atom or a hydroxyl group, which may be identical or different to any other X³ group if n³ is greater than 1, n³ represents an integer of from 1 to 4 and Y³ represents a hydrogen atom or a uni- to tetravalent metal atom; (iv) 1,4-butanediol; and (v) γ-butyrolactone.

Claim 7

A process according to claim 5 wherein the copolyester is as defined in claim 2 and the carbon source is a compound of formula (I).

Claim 8

A process according to claim 5 wherein the copolyester is as defined in claim 3 and the carbon source is a compound of formula (II), 1,4-butanediol or γ-butyrolactone.

Claim 9

A process according to claim 5 wherein the copolyester is as defined in claim 4 and the carbon source is a compound of formula (II) and a compound of formula (III).

Claim 10

A process according to any one of claims 5 to 8 wherein the microorganism belongs to the genus Alcaligenes .

Claim 11

A process according to claim 9 wherein the microorganism is Alcaligenes faecalis , Alcaligenes ruhlandii , Alcaligenes latus , Alcaligenes aquamarinus or Alcaligenes eutrophs .