Method for producing polyhydroxyalkanoate and use of same

Patent metadata

Field	Value
Publication number	US-2023123797-A1
Application number	US-202117759876-A
Country	US
Kind code	A1
Filing date	Jan 19, 2021
Priority date	Feb 12, 2020
Publication date	Apr 20, 2023
Grant date	—

Abstract

A method for producing a polyhydroxyalkanoate, the method including: (a) preparing an aqueous polyhydroxyalkanoate suspension having a pH of not more than 5; (b) mixing the aqueous suspension obtained in (a) with a water-insoluble organic solvent having a specific gravity of more than 1.0 g/mL; (c) separating a mixed solution obtained in (b) into a water-insoluble organic solvent phase and an aqueous phase by centrifugal separation, and then removing the aqueous phase; and (d) heating the water-insoluble organic solvent phase obtained in (c), and then cooling the water-insoluble organic solvent phase to obtain a gelatinous polyhydroxyalkanoate.

First claim

1 . A method for producing a polyhydroxyalkanoate, comprising:
(a) preparing an aqueous polyhydroxyalkanoate suspension having a pH of not more than 5; (b) mixing the aqueous suspension obtained in (a) with a water-insoluble organic solvent having a specific gravity of more than 1.0 g/mL, thereby obtaining a mixed solution; (c) separating the mixed solution obtained in (b) into a water-insoluble organic solvent phase and an aqueous phase by centrifugal separation, and then removing the aqueous phase; and (d) heating the water-insoluble organic solvent phase obtained in (c), and then cooling the water-insoluble organic solvent phase to obtain a gelatinous polyhydroxyalkanoate.

2 . The method of claim 1 , further comprising:
(e) washing, with an organic solvent, the gelatinous polyhydroxyalkanoate obtained in (d), and then drying the gelatinous polyhydroxyalkanoate to obtain a polyhydroxyalkanoate aggregate.

3 . The method of claim 1 , wherein the separating in (c) includes separating the mixed solution into a polyhydroxyalkanoate phase A, a water-insoluble organic solvent main component phase, a polyhydroxyalkanoate phase B, and a water main component phase in this order from a bottom, and removing the polyhydroxyalkanoate phase B and the water main component phase.

4 . The method of claim 3 , wherein, in (c), a value expressed by the following Expression (1) is not less than 45%:
volume of polyhydroxyalkanoate phase A /(volume of polyhydroxyalkanoate phase A +volume of polyhydroxyalkanoate phase B )×100  (1).

5 . The method of claim 1 , wherein the water-insoluble organic solvent is at least one selected from the group consisting of triacetin, dimethyl carbonate, tripropionin, propylene glycol diacetate, and tributyrin.

6 . The method of claim 1 , wherein a heating temperature in (d) is 50° C. to 150° C.

7 . The method of claim 1 , wherein a cooling temperature in (d) is lower than 50° C.

8 . A polyhydroxyalkanoate aggregate comprising:
a polyhydroxyalkanoate; and a water-insoluble organic solvent having a specific gravity of more than 1.0 g/mL.

9 . The polyhydroxyalkanoate aggregate of claim 8 , wherein the water-insoluble organic solvent is at least one selected from the group consisting of triacetin, dimethyl carbonate, tripropionin, propylene glycol diacetate, and tributyrin.

10 . The method of claim 1 , wherein the aqueous polyhydroxyalkanoate suspension in (a) comprises an aqueous medium and at least one polyhydroxyalkanoate selected from the group consisting of poly(3-hydroxybutyrate) (P3HB), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), poly(3-hydroxybutyrate-co hydroxyvalerate) (P3HB3HV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB).

11 . The method of claim 1 , wherein the aqueous polyhydroxyalkanoate suspension in (a) has a pH of not more than 3.

12 . The method of claim 1 , wherein the aqueous polyhydroxyalkanoate suspension in (a) has a pH of 1.4 to 3.

13 . The method of claim 1 , wherein aqueous polyhydroxyalkanoate suspension in (a) comprises from 30% by weight to 65% by weight of a polyhydroxyalkanoate.

14 . The method of claim 4 , wherein the value expressed by the Expression (1) is not less than 50%.

15 . The method of claim 1 , wherein a heating temperature in (d) is 60° C. to 130° C.

16 . The method of claim 1 , wherein a cooling temperature in (d) is 30° C. or less.

17 . The method of claim 2 , wherein the organic solvent in (e) is selected from the group consisting of isopropanol, ethanol, tert-butanol, methanol, acetone, and hexane.

18 . The method of claim 2 , wherein the polyhydroxyalkanoate aggregate obtained in (e) has a maximum diameter of from 0.1 cm to 10 cm.

19 . The polyhydroxyalkanoate aggregate of claim 8 , wherein the polyhydroxyalkanoate aggregate has a maximum diameter of 0.1 cm to 10 cm.

20 . The polyhydroxyalkanoate aggregate of claim 8 , wherein the polyhydroxyalkanoate aggregate has a maximum diameter of 1.0 cm to 8.0 cm.

Assignees

• Kaneka Corp

Inventors

• Hirano Masaru

Classifications

• C08G63/89 Primary

  Recovery of the polymer · CPC title

• C08G63/78

  Preparation processes · CPC title

• C08G63/06

  derived from hydroxycarboxylic acids · CPC title

• C08J3/16

  by coagulating dispersions {(C08J3/122 takes precedence)} · CPC title