Method for production polyhydroxybutyric acid resin

Patent metadata

Field	Value
Publication number	US-12516154-B2
Application number	US-202217818379-A
Country	US
Kind code	B2
Filing date	Aug 9, 2022
Priority date	Mar 18, 2020
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

In one or more embodiments, the present invention relates to a method for producing a polyhydroxybutyrate-based resin. The method includes (a) disrupting or solubilizing microbial cells containing a polyhydroxybutyrate-based resin, and (b) separating the polyhydroxybutyrate-based resin from a composition obtained by the process (a). The process (a) and the process (b) use water with a calcium ion concentration of 4.5 mg/L or less. The water used in the process (a) and the process (b) is preferably obtained by subjecting wastewater that is discharged from the production process of the polyhydroxybutyrate-based resin to microbial anaerobic and aerobic treatments, subsequently pre-filtration by a membrane bioreactor process, and further filtration with a calcium ion removal membrane. This method provides the polyhydroxybutyrate-based resin with good color tone and high thermal stability.

First claim

The invention claimed is:

1 . A method for producing a polyhydroxybutyrate-based resin, comprising:
disrupting or solubilizing microbial cells comprising a polyhydroxybutyrate-based resin, thereby obtaining a composition comprising the polyhydroxybutyrate-based resin; then separating the polyhydroxybutyrate-based resin from the composition and discharging the remaining liquid waste as wastewater, subjecting the wastewater discharged from the composition to microbial anaerobic and aerobic treatment, pre-filtering the wastewater obtained from the microbial anaerobic and aerobic treating using a membrane bioreactor process, filtrating the pre-filtered wastewater with a calcium ion removal membrane, thereby obtaining water, and reusing the obtained water in the disrupting or solubilizing and the separating in the production of polyhydroxybutyrate-based resin, wherein the water has a calcium ion concentration of 4.5 mg/L or less, wherein the calcium ion removal membrane is at least one selected from the group consisting of a nanofiltration (NF) membrane and a reverse osmosis (RO) membrane, and wherein an MgSO 4 rejection rate of the NF membrane or the RO membrane at a temperature of 20° C. and under a pressure of 3000 kPa is from 60% to 100%.

2 . The method according to claim 1 , wherein the water used in the disrupting or solubilizing and the separating has a sodium ion concentration of 450 mg/L or less.

3 . The method according to claim 1 , wherein the disrupting or solubilizing comprises at least one treatment selected from the group consisting of a chemical treatment and a physical disruption treatment.

4 . The method according to claim 3 , wherein the chemical treatment uses at least one selected from the group consisting of an alkaline compound, a proteolytic enzyme, and a cell wall degrading enzyme.

5 . The method according to claim 3 , wherein the physical disruption treatment is performed after an alkaline compound, or an alkaline compound and a surfactant, is/are added to the microbial cells.

6 . The method according to claim 1 , wherein the polyhydroxybutyrate-based resin is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).

7 . The method according to claim 1 , wherein the polyhydroxybutyrate-based resin has a weight average molecular weight retention of at least 70% when heat-treated at 160° C. for 20 minutes.

8 . The method according to claim 1 , wherein when the polyhydroxybutyrate-based resin is press molded at 160° C. to form a sheet with a thickness of 5 mm, a yellow index (YI value) of the sheet is 20 or less.

9 . The method according to claim 1 , further comprising:
drying the separated polyhydroxybutyrate-based resin.

10 . The method according to claim 1 , wherein the MgSO 4 rejection rate of the NF membrane or the RO membrane at a temperature of 20° C. and under a pressure of 3000 kPa is from 70% to 100%.

11 . The method according to claim 1 , wherein the MgSO 4 rejection rate of the NF membrane or the RO membrane at a temperature of 20° C. and under a pressure of 3000 kPa is from 90% to 100%.

12 . The method according to claim 1 , wherein a transmembrane pressure difference of the NF membrane or the RO membrane during the filtering is from 0.4 MPa to 4.14 MPa.

13 . The method according to claim 1 , wherein a permeation rate of the NF membrane or the RO membrane during the filtering is from 0.01 L/min to 2,000 L/min.

14 . A method for producing a polyhydroxybutyrate-based resin, comprising:
disrupting or solubilizing microbial cells comprising a polyhydroxybutyrate-based resin; separating the polyhydroxybutyrate-based resin from the composition, drying the separated polyhydroxybutyrate-based resin, thereby producing the polyhydroxybutyrate-based resin, and discharging liquid waste as wastewater from the production of polyhydroxybutyrate-based resin, subjecting the wastewater discharged from the production of polyhydroxybutyrate-based resin to microbial anaerobic and aerobic treatment, pre-filtering the wastewater obtained from the microbial anaerobic and aerobic treating using a membrane bioreactor process, filtrating the pre-filtered wastewater with a calcium ion removal membrane, thereby obtaining water, and reusing the obtained water in the production of the polyhydroxybutyrate-based resin, wherein the water has a calcium ion concentration of 4.5 mg/L or less, wherein the calcium ion removal membrane is at least one selected from the group consisting of a nanofiltration (NF) membrane and a reverse osmosis (RO) membrane, and wherein an MgSO 4 rejection rate of the NF membrane or the RO membrane at a temperature of 20° C. and under a pressure of 3000 kPa is from 60% to 100%.

Assignees

• Kaneka Corp

Inventors

• Fukumoto Asuka
• Hirota Shogo
• Hirano Masaru

Classifications

• C08G63/06

  derived from hydroxycarboxylic acids · CPC title

• C02F2103/38

  Polymers · CPC title

• C02F2101/10

  Inorganic compounds · CPC title

• C02F1/44

  by dialysis, osmosis or reverse osmosis {(general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268)} · CPC title

• Y02W10/10

  Biological treatment of water, waste water, or sewage · CPC title