WO2020100598A1 - Method for producing aqueous polyhydroxyalkanoate dispersion - Google Patents

Method for producing aqueous polyhydroxyalkanoate dispersion Download PDF

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WO2020100598A1
WO2020100598A1 PCT/JP2019/042634 JP2019042634W WO2020100598A1 WO 2020100598 A1 WO2020100598 A1 WO 2020100598A1 JP 2019042634 W JP2019042634 W JP 2019042634W WO 2020100598 A1 WO2020100598 A1 WO 2020100598A1
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pha
aqueous dispersion
polyhydroxyalkanoate
producing
weight
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PCT/JP2019/042634
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French (fr)
Japanese (ja)
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省二郎 大隅
彰仁 熊見
崇吉 長谷川
隼人 前田
郁弥 迫
智哉 西中
松村　邦彦
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株式会社カネカ
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/26—Polyalkenes
    • B01D71/262—Polypropylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/04—Tubular membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/26—Polyalkenes
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
    • C12P7/00—Preparation of oxygen-containing organic compounds
    • C12P7/62—Carboxylic acid esters

Definitions

  • the present invention relates to a method for producing a polyhydroxyalkanoate aqueous dispersion having a concentration step by membrane separation.
  • Polyhydroxyalkanoate (hereinafter also referred to as PHA) is a thermoplastic polyester that is produced and accumulated as an energy storage substance in cells of many microbial species, and has biodegradability.
  • PHA Polyhydroxyalkanoate
  • non-petroleum-derived plastics are attracting attention due to increasing environmental awareness.
  • biodegradable plastics such as PHA, which are taken into the natural material cycle and whose decomposition products are not harmful, are receiving attention, and their practical application is earnestly desired.
  • PHA produced and accumulated by microorganisms in the cells is expected to have little adverse effect on the ecosystem because it is incorporated into the carbon cycle process in nature.
  • PHA is produced by a culture step of accumulating PHA in bacterial cells, a separation and purification step of recovering PHA from the bacterial cells, and a PHA drying step. Since the PHA aqueous dispersion obtained by the separation and purification process contains a large amount of water, it takes a long time and a large amount of energy is consumed in performing the drying process. As a method of reducing the time and energy required for drying, there is a method of concentrating the PHA aqueous dispersion after the separation and purification step. Examples of the method for concentrating the PHA aqueous dispersion include a method by centrifugation and a method by evaporation.
  • a cross-flow membrane separation method has been studied as a method capable of solving the above-mentioned problems when using a centrifugal separation method or an evaporation method (for example, see Patent Document 1).
  • Permeation flux and pressure loss become problems when the membrane separation process is used industrially. In industrial production, a high permeation flux is required to secure productivity. On the other hand, since high pressure deteriorates the membrane, operation at low pressure is required for long-term use of the membrane.
  • Patent Document 1 discloses a method including a step of subjecting a PHA suspension to tangential filtration, and a ceramic membrane or polymer membrane having an average pore size of 0.05 to 10 ⁇ m, preferably 0.2 to 5 ⁇ m. Is disclosed.
  • Patent Document 1 causes a significant decrease in permeation flux due to blockage of PHA particles, and a sharp increase in pressure due to an increase in viscosity of the PHA aqueous dispersion. It has been found that due to such a large increase, the PHA aqueous dispersion may not be concentrated to a high concentration of 50% by weight or more while maintaining a high permeation flux and a low pressure.
  • an object of the present invention is to provide a method for producing a PHA water dispersion liquid, which can obtain a concentrated PHA water dispersion liquid having a solid content concentration of more than 50% by weight, without significantly reducing the permeation flux and the pressure. To provide.
  • the present inventors have completed the present invention as a result of intensive studies for solving the above-mentioned problems.
  • the present invention provides the inventions according to the following [1] to [6], for example.
  • a method for producing an aqueous dispersion of polyhydroxyalkanoate wherein an aqueous dispersion of polyhydroxyalkanoate having a median diameter of polyhydroxyalkanoate particles of 1 to 5 ⁇ m and a solid content concentration of less than 50% by weight is used.
  • a process for producing an aqueous dispersion of polyhydroxyalkanoate which comprises the step of feeding the solution into a tubular membrane having a diameter of 4 to 10 mm and an average pore diameter of 0.05 to 0.5 ⁇ m to concentrate the solid content concentration to 50% by weight or more.
  • the PHA aqueous dispersion can be concentrated to a high concentration exceeding 50% by weight with high productivity by membrane separation.
  • the energy and time required for drying the PHA can be significantly reduced.
  • by lowering the pressure applied to the film it is possible to extend the life of the film.
  • 5 is a graph showing the solid content concentration of the PHA aqueous dispersion and the pressure loss of the membrane measured in Example 1 and Comparative Example 1.
  • 5 is a graph showing the solid content concentration of the PHA aqueous dispersion and the permeation flux of the membrane measured in Example 2 and Comparative Example 2. It is the schematic of the apparatus used for the concentration of the PHA aqueous dispersion in an Example.
  • the method for producing a PHA aqueous dispersion according to the present invention is a method for producing a PHA aqueous dispersion, which comprises the following step (a) of concentrating the PHA aqueous dispersion as an essential step.
  • the filtration method carried out by feeding the liquid into the tubular membrane in the step (a) is a cross flow method (a method in which the flow directions of the liquid to be filtered and the filtrate are orthogonal to each other), a dead end method (the liquid to be filtered and the filtrate).
  • the cross-flow method is preferable from the viewpoint of suppressing flow path clogging by PHA particles.
  • the PHA aqueous dispersion to be concentrated in step (a) of the method for producing a PHA aqueous dispersion of the present invention is an aqueous dispersion in which PHA particles are dispersed in water, and as described above, the median diameter of PHA particles is Is 1 to 5 ⁇ m and the solid content concentration is less than 50% by weight.
  • aqueous dispersion for example, a PHA obtained by producing PHA by a PHA-producing microorganism, and then chemically and / or physically and / or biologically treating the microorganism (PHA-containing bacterium) in water. It may be an aqueous dispersion. That is, the step (a) may be a step performed after culturing a PHA-producing microorganism (production of PHA) and separating and purifying PHA from the microorganism.
  • a method of solubilizing with a chemical such as an acid, an alkali, a surfactant, an organic solvent, or a cell wall synthesis inhibitor is preferable.
  • a chemical such as an acid, an alkali, a surfactant, an organic solvent, or a cell wall synthesis inhibitor.
  • a physical treatment for example, conventionally known French press, high-pressure homogenizer, X-press, ball mill, colloid mill, DYNO mill, ultrasonic homogenizer, fluid shear force, solid shear force, or grinding can be used.
  • a solution method is preferred.
  • a method using an enzyme such as lysozyme, pectinase, cellulase, thymolyase, and alcalase, and a crushing method of an autolysis method utilizing the action of protease or esterase contained in the cell itself are preferable.
  • the culture of PHA-producing microorganisms can be carried out according to a known or commonly used method and is not particularly limited. For example, it can be carried out by the method described in International Publication No. 2010/116681.
  • PHA contained in the PHA aqueous dispersion produced by the present invention has the following general formula (1): [-CHR-CH 2 -CO-O-] (1) (In the formula, R is an alkyl group represented by C n H 2n + 1 , and n is an integer of 1 or more and 15 or less.) It is preferable that it is at least one or more PHA containing the repeating unit shown by.
  • the PHA preferably contains the repeating unit represented by the general formula (1) in an amount of 50 mol% or more of all repeating units, and may further contain other repeating structures. In particular, it is more preferable that the repeating unit represented by the general formula (1) is contained in an amount of 70 mol% or more based on all the repeating units, and further preferably 80 mol% or more.
  • PHA examples include poly (3-hydroxybutyrate) (PHB), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and [poly (3-hydroxybutyrate-co- 3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly (3-hydroxybutyrate-co- 4-hydroxybutyrate) (P3HB4HB), poly (3-hydroxybutyrate-co-3-hydroxyoctanoate), poly (3-hydroxybutyrate-co-3-hydroxyoctadecanoate), poly (3 -Hydroxybutyrate-co-3-hydroxy-4-methylvalerate) (P3HB3H4MV) and the like.
  • PHB, PHBV, P3HB3HV3HH, PHBH, and P3HB4HB are particularly preferable because they are relatively easily industrially produced.
  • the average composition ratio of the repeating structural unit is 80 to 99 mol% from the viewpoint of the balance between flexibility and strength of PHA. Is preferred.
  • the PHA aqueous dispersion produced by the present invention may have one PHA alone or may have two or more PHA in combination.
  • the median diameter of PHA particles in the PHA aqueous dispersion to be concentrated in the step (a) is 1 to 5 ⁇ m, preferably 2 to 5 ⁇ m.
  • the median diameter is measured by the laser diffraction method.
  • the median diameter of PHA particles in the PHA aqueous dispersion can be adjusted by controlling the culture time, for example, when PHA is produced by culturing PHA-producing bacteria. For example, if the culture time is lengthened, the median diameter tends to increase.
  • the solid content concentration of the PHA aqueous dispersion to be concentrated in the step (a) is less than 50% by weight, and from the viewpoint of more effectively enjoying the effect of the present invention, preferably less than 45% by weight, more preferably It is less than 40% by weight, more preferably less than 35% by weight.
  • the lower limit of the solid content concentration is not particularly limited, but from the viewpoint of ensuring productivity, it is preferably 18% by weight or more, more preferably 20% by weight or more, and further preferably 25% by weight or more.
  • the PHA water dispersion liquid to be concentrated in the step (a) may contain water and other components other than PHA particles.
  • Other components include solvents other than water (for example, alcohols such as methanol, ethanol and ethylene glycol; ethers such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether), dispersants (for example, polyvinyl alcohol (PVA), Water-soluble polymers such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, polymethacrylic acid, sodium polymethacrylate, etc., surfactants (eg sodium dodecyl sulfate) , Anionic surfactants such as sodium dodecylbenzenesulfonate, sodium cholate, sodium deoxycholate and sodium oleate; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyalkylene alkyl ethers
  • Step (a) is a step of feeding the PHA aqueous dispersion into the tubular membrane (that is, filtering the PHA aqueous dispersion through the tubular membrane) and concentrating the aqueous dispersion.
  • the filtration using the tubular membrane is preferably filtration by a cross flow method (cross flow filtration).
  • Cross-flow filtration is a filtration method in which the treatment liquid has a relative velocity in the horizontal direction with respect to the membrane surface.
  • the average pore size of the tubular membrane which is the filtration membrane used in step (a), is 0.05 to 0.5 ⁇ m, more preferably 0.1 to 0.3 ⁇ m. If the average pore size of the tubular membrane is less than 0.05 ⁇ m, the permeation flux becomes low, and the membrane area required for industrial use becomes large, which increases costs and is not preferable. On the other hand, when the average pore diameter exceeds 0.5 ⁇ m, PHA particles enter the pores, the permeation flux is significantly reduced, and as a result, the required membrane area increases. Furthermore, it is not preferable because it becomes difficult to regenerate the film by washing and the cost increases in industrial use.
  • the average pore size of the tubular membrane is determined by the removal rate of inorganic particles whose average particle size is known.
  • the method for measuring the average pore diameter of a tubular membrane having an average pore diameter of 0.2 ⁇ m is as follows. Water was added to silica particles having an average particle diameter of 0.1 ⁇ m, and an aqueous dispersion of silica particles (test solution) at 200 mg / L was continuously introduced into the tubular membrane by a cross flow method with an inlet pressure of 0.03 MPa and a liquid temperature of room temperature. By passing the solution, the aqueous dispersion of silica particles is concentrated three times. Further, the same operation is performed on silica particles having an average particle diameter of 0.3 ⁇ m.
  • Removal rate (%) (1- (turbidity of filtrate / (turbidity of test liquid + turbidity of concentrated liquid) / 2)) ⁇ 100. If the removal rate of silica particles having an average particle size of 0.1 ⁇ m is 50% or less and the removal rate of silica particles having an average particle size of 0.3 ⁇ m is 95% or more, the average pore size of the tubular membrane is determined to be 0.2 ⁇ m.
  • the inner diameter of the tubular membrane is 4 to 10 mm, preferably 4 to 7 mm. If the inner diameter is less than 4 mm, the PHA aqueous dispersion whose viscosity has increased due to concentration tends to be clogged in the tubular membrane, making concentration impossible, which is not preferable. On the other hand, when the inner diameter exceeds 10 mm, the linear velocity applied to the film surface (the surface of the PHA particle layer formed on the film surface) decreases, so the force for peeling the PHA particle layer deposited on the film surface becomes weak and The PHA particle layer formed in the above becomes thick and the permeation flux becomes small, that is, the concentration time tends to increase. In addition, the number of membrane modules required increases, and the cost increases in industrial use, which is not preferable.
  • the inner diameter of the tubular membrane means the inner diameter of the circular hollow cross section of the tubular membrane.
  • the material of the tubular membrane (filtration membrane) is not particularly limited, but for example, polypropylene, fluororesin (eg, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene / propylene hexafluoride copolymer) Polymer, ethylene / tetrafluoroethylene copolymer, etc.), cellulose ester (eg, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, etc.), polysulfone resin (eg, polysulfone, polyether sulfone, etc.), poly Resins such as acrylonitrile and polyimide; porous ceramics such as alumina, mullite, zirconia, and cordierite; and inorganic materials such as porous bodies made of porous sintered metal such as stainless steel.
  • fluororesin eg, polytetrafluoroethylene, polyviny
  • step (a) the PHA aqueous dispersion is concentrated by passing it through the tubular membrane.
  • the filtration operation using the tubular membrane can be carried out by a known or common procedure.
  • the number of times the liquid is passed through the tubular membrane is not particularly limited, and usually, the PHA aqueous dispersion is concentrated by allowing the water to gradually permeate out of the tubular membrane by circulating the water inside the tubular membrane many times.
  • the transmembrane pressure difference when supplying the PHA aqueous dispersion to the tubular membrane is not particularly limited, but is preferably 0.001 to 0.1 MPa, and more preferably 0.01 to 0.1 MPa.
  • the transmembrane pressure difference is less than 0.001 MPa, the propulsive force required for filtration is insufficient and filtration is not performed, which is not preferable.
  • the transmembrane pressure difference exceeds 0.1 MPa, deterioration of the membrane due to the pressure tends to occur, which is not preferable.
  • the linear velocity at the time of concentrating the PHA aqueous dispersion is not particularly limited, but is preferably 1 to 5 m / s, more preferably 1.5 to 4 m / s, and further preferably Is 2 to 4 m / s.
  • the tubular film is made of resin (for example, polypropylene)
  • the upper limit of the linear velocity is preferably 3 m / s or less from the viewpoint of durability.
  • the pressure loss when concentrating the PHA aqueous dispersion is not particularly limited, but the pressure loss when concentrating the solid content concentration to 50% by weight is preferably 0.1 MPa or less, more preferably 0.05 MPa or less. Is. When it exceeds 0.1 MPa, the pressure tends to cause deterioration of the film, which is not preferable.
  • the permeation flux at the time of concentrating the PHA aqueous dispersion is not particularly limited, but the permeation flux at the time of concentrating the solid content concentration to 50% by weight is preferably 10 kg / m 2 ⁇ h or more, and more preferably Is 20 kg / m 2 ⁇ h or more. If it is less than 10 kg / m 2 ⁇ h, a large membrane area is required for industrial use, and the cost increases, which is not preferable.
  • a concentrated PHA aqueous dispersion is obtained.
  • the solid content concentration of the PHA aqueous dispersion obtained in step (a) is 50% by weight or more, preferably 52% by weight or more, more preferably 54% by weight or more.
  • the upper limit is not particularly limited, but from the viewpoint of securing the fluidity of the PHA aqueous dispersion, it is preferably 65% by weight or less, more preferably 60% by weight or less.
  • the method for producing a PHA water dispersion according to the present invention includes an additive (for example, the above-mentioned other components to the PHA water dispersion obtained in the step (a) other than the step (a). Component, etc.), a step of removing a part of water, etc.) may be included. Further, before the step (a), a step of culturing a PHA-producing bacterium, a step of obtaining a PHA aqueous dispersion from PHA-containing microbial cells obtained by the culturing (for example, a step of performing the above-mentioned separation and purification treatment, etc. ) May be included.
  • an additive for example, the above-mentioned other components to the PHA water dispersion obtained in the step (a) other than the step (a). Component, etc.
  • a step of removing a part of water, etc. may be included.
  • a step of culturing a PHA-producing bacterium a step
  • the PHA aqueous dispersion obtained by the method for producing a PHA aqueous dispersion of the present invention can be used as a raw material for various molded products such as films and coatings.
  • a solid PHA can be obtained by drying and removing water.
  • Example 1 The Ralstonia eutropha KNK-005 strain was cultured by the method described in Example 1 of WO 2010/116681 and contained poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).
  • a cell culture solution was prepared.
  • the bacterial cell culture solution obtained above was sterilized by heating and stirring at an internal temperature of 60 to 80 ° C. for 20 minutes.
  • 0.2% by weight of sodium dodecyl sulfate was added to the sterilized cell culture solution obtained above.
  • an aqueous sodium hydroxide solution was added to adjust the pH to 11.0, and then the mixture was kept at 50 ° C. for 1 hour.
  • high-pressure crushing was performed using a high-pressure crusher (high-pressure homogenizer model PA2K type manufactured by Niro Soavi Co., Ltd.) at a pressure of 450 to 550 kgf / cm 2 .
  • An equal amount of distilled water was added to the crushed liquid obtained after high-pressure crushing. After centrifuging this, the supernatant was removed and concentrated twice.
  • the same amount of sodium hydroxide aqueous solution (pH 11) as the removed supernatant was added and centrifuged, and after removing the supernatant, water was added again to suspend.
  • PHBH aqueous dispersion having a median diameter of PHBH particles of 2 ⁇ m and a solid content concentration of 18% by weight (PHBH particle content: 180 g / L) was obtained.
  • the solution was circulated and supplied (delivered) at / s for concentration.
  • the PHA aqueous dispersion is concentrated by removing the filtrate from the tubular membrane 1 outside the system.
  • the pressure loss during concentration and the solid content concentration of the PHA aqueous dispersion after concentration were measured, and the results are shown in FIG. 1 together with the result of Comparative Example 1.
  • Example 1 the pressure loss was not significantly increased, the pressure loss could be 50 kPa or less, and the concentration to the solid content concentration of 50% by weight or more could be achieved while maintaining the low pressure.
  • the pressure loss was calculated by measuring the inlet pressure and the outlet pressure using pressure gauges 5 and 5 ′ installed at the inlet and the outlet of the tubular membrane 1 of FIG. 3, and subtracting the outlet pressure from the inlet pressure.
  • Pressure loss (inlet pressure)-(outlet pressure)
  • the solid content concentration was calculated by the following formula after measuring the weight of the PHA aqueous dispersion and then measuring the weight of PHA after removing water from the PHA aqueous dispersion.
  • Solid content concentration (wt%) (PHA weight) / (PHA aqueous dispersion weight) ⁇ 100
  • Example 1 The median diameter of PHBH particles was 2 ⁇ m in the same manner as in Example 1 except that the amount of water added last was changed using the cell culture solution obtained in the same manner as in Example 1.
  • the PHBH aqueous dispersion was placed in the tank 3, and circulated and supplied (liquid transfer) to a polypropylene hollow fiber membrane (MICRODYN R MD020CP2N) having an average pore diameter of 0.2 ⁇ m and an inner diameter of 1.8 mm at a linear velocity of 2 m / s, Concentration was carried out.
  • MICRODYN R MD020CP2N polypropylene hollow fiber membrane having an average pore diameter of 0.2 ⁇ m and an inner diameter of 1.8 mm at a linear velocity of 2 m / s
  • Example 2 Using the bacterial cell culture solution obtained by the same method as in Example 1, the median diameter of PHBH particles was 2 ⁇ m and the solid content concentration was 18% by weight (the content of PHBH particles was the same as in Example 1). : 180 g / L) to obtain a PHBH aqueous dispersion.
  • the PHBH aqueous dispersion is charged into a tank 3, and is circulated and supplied (liquid transfer) at a linear velocity of 2 m / s to a polypropylene tubular membrane (MICRODYN R MD020TP2N) having an average pore diameter of 0.2 ⁇ m and an inner diameter of 5.5 mm, and concentrated. was carried out.
  • MICRODYN R MD020TP2N polypropylene tubular membrane having an average pore diameter of 0.2 ⁇ m and an inner diameter of 5.5 mm
  • Example 2 The permeation flux at the time of concentration and the solid content concentration of the PHA aqueous dispersion after concentration were measured, and the results are shown together with the result of Comparative Example 2 in FIG. From this, in Example 2, it was possible to achieve concentration to a solid content concentration of 50% by weight or more while maintaining the permeation flux at 10 kg / m 2 ⁇ h or more.
  • the permeation flux was calculated by measuring the permeation liquid (PHA water dispersion liquid) for 1 minute and dividing it by the membrane area. Further, the solid content concentration was calculated by the above-described method and formula.
  • Example 2 The median diameter of PHBH particles was 2 ⁇ m in the same manner as in Example 1 except that the amount of water added last was changed using the cell culture solution obtained in the same manner as in Example 1.
  • a PHBH aqueous dispersion having a solid content concentration of 10% by weight (PHBH particle content: 100 g / L) was obtained.
  • Put the PHBH aqueous dispersion tank 3, and an average pore diameter 1.0 .mu.m, circulated and supplied into a polyethylene tubular film having an inner diameter of 5mm (SEPRODYN R SE020TP1N) at a linear velocity of 2m / s (liquid feed), carried out concentrated did.

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Abstract

A method for producing an aqueous polyhydroxyalkanoate dispersion, the method including a step in which an aqueous polyhydroxyalkanoate dispersion containing polyhydroxyalkanoate particles with a median diameter of 1-5 μm and having a solid concentration less than 50 wt% is sent into a tubular membrane having an inner diameter of 4-10 mm and an average pore diameter of 0.05-0.5 μm to heighten the solid concentration to 50 wt% or greater.

Description

ポリヒドロキシアルカノエート水分散液の製造方法Method for producing polyhydroxyalkanoate aqueous dispersion
　本発明は、膜分離による濃縮工程を有するポリヒドロキシアルカノエート水分散液の製造方法に関する。 The present invention relates to a method for producing a polyhydroxyalkanoate aqueous dispersion having a concentration step by membrane separation.
　ポリヒドロキシアルカノエート（以下、ＰＨＡともいう）は、多くの微生物種の細胞にエネルギー蓄積物質として生成、蓄積される熱可塑性ポリエステルであり、生分解性を有している。現在、環境への意識の高まりから非石油由来のプラスチックが着目されている。中でも、自然界の物質循環に取り込まれ分解生成物が有害とならないＰＨＡの様な生分解性プラスチックが注目されており、その実用化が切望されている。特に、微生物が菌体内で生成蓄積するＰＨＡは、自然界の炭素循環プロセスに取り込まれることから生態系への悪影響が小さいと予想されている。 Polyhydroxyalkanoate (hereinafter also referred to as PHA) is a thermoplastic polyester that is produced and accumulated as an energy storage substance in cells of many microbial species, and has biodegradability. At present, non-petroleum-derived plastics are attracting attention due to increasing environmental awareness. Of these, biodegradable plastics such as PHA, which are taken into the natural material cycle and whose decomposition products are not harmful, are receiving attention, and their practical application is earnestly desired. In particular, PHA produced and accumulated by microorganisms in the cells is expected to have little adverse effect on the ecosystem because it is incorporated into the carbon cycle process in nature.
　ＰＨＡは、概して、菌体にＰＨＡを蓄積する培養工程に続いて、菌体からＰＨＡを回収する分離精製工程、ＰＨＡの乾燥工程により製造される。分離精製工程によって得られるＰＨＡ水分散液は大量の水を含んでいるため、乾燥工程の実施において、長い時間を必要とし、大量のエネルギーを消費する。乾燥に必要な時間やエネルギーを軽減させる方法として、分離精製工程後にＰＨＡ水分散液を濃縮する方法がある。ＰＨＡ水分散液を濃縮する方法としては、例えば、遠心分離による方法や蒸発による方法等が挙げられる。しかし、前者の遠心分離による方法においては、ＰＨＡ水分散液を高濃度まで濃縮できない、連続運転が困難である等の課題があった。一方、後者の蒸発による方法では、高温をかけることによりＰＨＡの分子量が大きく低下する課題があった。 Generally, PHA is produced by a culture step of accumulating PHA in bacterial cells, a separation and purification step of recovering PHA from the bacterial cells, and a PHA drying step. Since the PHA aqueous dispersion obtained by the separation and purification process contains a large amount of water, it takes a long time and a large amount of energy is consumed in performing the drying process. As a method of reducing the time and energy required for drying, there is a method of concentrating the PHA aqueous dispersion after the separation and purification step. Examples of the method for concentrating the PHA aqueous dispersion include a method by centrifugation and a method by evaporation. However, in the former method by centrifugation, there are problems that the PHA aqueous dispersion cannot be concentrated to a high concentration, continuous operation is difficult, and the like. On the other hand, in the latter method by evaporation, there is a problem that the molecular weight of PHA is significantly reduced by applying a high temperature.
　遠心分離法や蒸発法を使用した場合の上述の課題を解決し得る方法として、クロスフロー式の膜分離法が検討されてきた（例えば、特許文献１参照）。膜分離プロセスを特に工業的に利用する場合、透過流束や圧力損失が課題となる。工業的な生産においては生産性確保のため、高い透過流束が必要となる。一方、高い圧力は膜を劣化させることから、膜を長期的に使用するためには低い圧力での運転が求められる。 A cross-flow membrane separation method has been studied as a method capable of solving the above-mentioned problems when using a centrifugal separation method or an evaporation method (for example, see Patent Document 1). Permeation flux and pressure loss become problems when the membrane separation process is used industrially. In industrial production, a high permeation flux is required to secure productivity. On the other hand, since high pressure deteriorates the membrane, operation at low pressure is required for long-term use of the membrane.
特表２０１６－５２４９２６号公報Japanese Patent Publication No. 2016-524926
　特許文献１には、ＰＨＡ懸濁液をタンジェンシャルろ過に掛ける工程を含む方法が開示されており、０．０５～１０μｍ、好ましくは０．２～５μｍの平均孔寸法を持つセラミック膜又はポリマー膜を使用することが開示されている。 Patent Document 1 discloses a method including a step of subjecting a PHA suspension to tangential filtration, and a ceramic membrane or polymer membrane having an average pore size of 0.05 to 10 μm, preferably 0.2 to 5 μm. Is disclosed.
　しかしながら、本発明者らは検討の結果、特許文献１に開示された方法では、ＰＨＡ粒子の閉塞による透過流束の大幅な低下が生じたり、また、ＰＨＡ水分散液の粘度上昇による圧力の急激な増大により、高い透過流束及び低い圧力を維持したままＰＨＡ水分散液を５０重量％以上という高濃度には濃縮できない場合があることがわかった。 However, as a result of investigations by the present inventors, the method disclosed in Patent Document 1 causes a significant decrease in permeation flux due to blockage of PHA particles, and a sharp increase in pressure due to an increase in viscosity of the PHA aqueous dispersion. It has been found that due to such a large increase, the PHA aqueous dispersion may not be concentrated to a high concentration of 50% by weight or more while maintaining a high permeation flux and a low pressure.
　したがって、本発明の目的は、透過流束の大幅な低下や圧力の大幅な増大なく、固形分濃度が５０重量％を超える濃厚なＰＨＡ水分散液を得ることができるＰＨＡ水分散液の製造方法を提供することにある。 Therefore, an object of the present invention is to provide a method for producing a PHA water dispersion liquid, which can obtain a concentrated PHA water dispersion liquid having a solid content concentration of more than 50% by weight, without significantly reducing the permeation flux and the pressure. To provide.
　本発明者らは、前述の課題解決のために鋭意検討を行った結果、本発明を完成するに至った。 The present inventors have completed the present invention as a result of intensive studies for solving the above-mentioned problems.
　すなわち本発明は、例えば、下記［１］～［６］に係る発明を提供する。 That is, the present invention provides the inventions according to the following [1] to [6], for example.
［１］ポリヒドロキシアルカノエート水分散液の製造方法であって、ポリヒドロキシアルカノエート粒子のメディアン径が１～５μｍであり固形分濃度が５０重量％未満のポリヒドロキシアルカノエート水分散液を、内径４～１０ｍｍ、平均細孔径０．０５～０．５μｍの管状膜内に送液して固形分濃度を５０重量％以上に濃縮する工程を含む、ポリヒドロキシアルカノエート水分散液の製造方法。 [1] A method for producing an aqueous dispersion of polyhydroxyalkanoate, wherein an aqueous dispersion of polyhydroxyalkanoate having a median diameter of polyhydroxyalkanoate particles of 1 to 5 μm and a solid content concentration of less than 50% by weight is used. A process for producing an aqueous dispersion of polyhydroxyalkanoate, which comprises the step of feeding the solution into a tubular membrane having a diameter of 4 to 10 mm and an average pore diameter of 0.05 to 0.5 μm to concentrate the solid content concentration to 50% by weight or more.
［２］前記管状膜内に送液して濃縮する前のポリヒドロキシアルカノエート水分散液の固形分濃度が４５重量％未満である、［１］に記載のポリヒドロキシアルカノエート水分散液の製造方法。 [2] Production of the polyhydroxyalkanoate aqueous dispersion according to [1], wherein the solid content concentration of the polyhydroxyalkanoate aqueous dispersion before being fed into the tubular membrane and concentrated is less than 45% by weight. Method.
［３］前記管状膜内に送液して濃縮する前のポリヒドロキシアルカノエート水分散液の固形分濃度が４０重量％未満である、［１］に記載のポリヒドロキシアルカノエート水分散液の製造方法。 [3] Production of the polyhydroxyalkanoate aqueous dispersion according to [1], wherein the solid content concentration of the polyhydroxyalkanoate aqueous dispersion before being fed into the tubular membrane and concentrated is less than 40% by weight. Method.
［４］前記管状膜内に送液するポリヒドロキシアルカノエート水分散液の線速度が１～３ｍ／ｓである、［１］～［３］のいずれか１つに記載のポリヒドロキシアルカノエート水分散液の製造方法。 [4] The polyhydroxyalkanoate water according to any one of [1] to [3], wherein the linear velocity of the polyhydroxyalkanoate aqueous dispersion liquid fed into the tubular membrane is 1 to 3 m / s. Dispersion manufacturing method.
［５］前記工程の前に、ポリヒドロキシアルカノエート生産菌の培養により得られたポリヒドロキシアルカノエート含有菌体からポリヒドロキシアルカノエート水分散液を得る工程をさらに含む、［１］～［４］のいずれか１つに記載のポリヒドロキシアルカノエート水分散液の製造方法。 [5] [1] to [4] further comprising a step of obtaining an aqueous dispersion of polyhydroxyalkanoate from the polyhydroxyalkanoate-containing cells obtained by culturing the polyhydroxyalkanoate-producing bacterium before the above step. The method for producing the polyhydroxyalkanoate aqueous dispersion according to any one of 1.
［６］前記管状膜がポリプロピレン製の管状膜である、［１］～［５］のいずれか１つに記載のポリヒドロキシアルカノエート水分散液の製造方法。 [6] The method for producing an aqueous dispersion of polyhydroxyalkanoate according to any one of [1] to [5], wherein the tubular membrane is a polypropylene tubular membrane.
　本発明によれば、膜分離により、高い生産性でＰＨＡ水分散液を５０重量％を超える高濃度まで濃縮することができる。結果、ＰＨＡの乾燥に要するエネルギーや時間を大幅に削減できる。また、膜にかかる圧力を下げることにより、膜の長寿命化が達成できる。 According to the present invention, the PHA aqueous dispersion can be concentrated to a high concentration exceeding 50% by weight with high productivity by membrane separation. As a result, the energy and time required for drying the PHA can be significantly reduced. Further, by lowering the pressure applied to the film, it is possible to extend the life of the film.
実施例１及び比較例１において測定したＰＨＡ水分散液の固形分濃度と膜の圧力損失を示すグラフである。5 is a graph showing the solid content concentration of the PHA aqueous dispersion and the pressure loss of the membrane measured in Example 1 and Comparative Example 1. 実施例２及び比較例２において測定したＰＨＡ水分散液の固形分濃度と膜の透過流束を示すグラフである。5 is a graph showing the solid content concentration of the PHA aqueous dispersion and the permeation flux of the membrane measured in Example 2 and Comparative Example 2. 実施例においてＰＨＡ水分散液の濃縮に使用した装置の概略図である。It is the schematic of the apparatus used for the concentration of the PHA aqueous dispersion in an Example.
　以下、本発明について詳細に説明するが、本発明は以下の態様に限定されるものではない。 The present invention will be described in detail below, but the present invention is not limited to the following modes.
　＜ＰＨＡ水分散液の製造方法＞
　本発明に係るＰＨＡ水分散液の製造方法は、ＰＨＡ水分散液を濃縮する下記の工程（ａ）を必須の工程として含む、ＰＨＡ水分散液の製造方法である。
　工程（ａ）：ＰＨＡ粒子のメディアン径が１～５μｍであり固形分濃度が５０重量％未満のＰＨＡ水分散液を、管状膜内に送液して、その固形分濃度を５０重量％以上に濃縮する工程 <Method for producing PHA aqueous dispersion>
The method for producing a PHA aqueous dispersion according to the present invention is a method for producing a PHA aqueous dispersion, which comprises the following step (a) of concentrating the PHA aqueous dispersion as an essential step.
Step (a): A PHA aqueous dispersion having a median diameter of PHA particles of 1 to 5 μm and a solid content concentration of less than 50% by weight is fed into a tubular membrane to increase the solid content concentration to 50% by weight or more. Concentrating process
　工程（ａ）における管状膜内に送液して実施するろ過の方式は、クロスフロー方式（被ろ過液とろ液との流れの方向が直交する方式）、デッドエンド方式（被ろ過液とろ液との流れの方向が同じ方式）のいずれであってもよいが、ＰＨＡ粒子による流路閉塞抑制の観点で、クロスフロー方式が好ましい。 The filtration method carried out by feeding the liquid into the tubular membrane in the step (a) is a cross flow method (a method in which the flow directions of the liquid to be filtered and the filtrate are orthogonal to each other), a dead end method (the liquid to be filtered and the filtrate). However, the cross-flow method is preferable from the viewpoint of suppressing flow path clogging by PHA particles.
　本発明のＰＨＡ水分散液の製造方法の工程（ａ）において濃縮する対象であるＰＨＡ水分散液は、水にＰＨＡ粒子が分散した水分散液であり、上述のように、ＰＨＡ粒子のメディアン径が１～５μｍであり固形分濃度が５０重量％未満であるものであればよい。当該水分散液としては、例えば、ＰＨＡ生産微生物によってＰＨＡを産生させた後、当該微生物（ＰＨＡ含有菌体）を水中で化学的及び／又は物理的、及び／又は生物的処理して得られるＰＨＡ水分散液であってもよい。すなわち、工程（ａ）は、ＰＨＡ生産微生物の培養（ＰＨＡの産生）、当該微生物からのＰＨＡの分離精製処理の後に実施される工程であってもよい。 The PHA aqueous dispersion to be concentrated in step (a) of the method for producing a PHA aqueous dispersion of the present invention is an aqueous dispersion in which PHA particles are dispersed in water, and as described above, the median diameter of PHA particles is Is 1 to 5 μm and the solid content concentration is less than 50% by weight. As the aqueous dispersion, for example, a PHA obtained by producing PHA by a PHA-producing microorganism, and then chemically and / or physically and / or biologically treating the microorganism (PHA-containing bacterium) in water. It may be an aqueous dispersion. That is, the step (a) may be a step performed after culturing a PHA-producing microorganism (production of PHA) and separating and purifying PHA from the microorganism.
　上述の化学的処理としては、例えば、酸やアルカリ、界面活性剤、有機溶剤、細胞壁合成阻害剤などの薬剤を用いて可溶化する方法が好ましい。物理的処理としては、例えば、従来公知のフレンチプレスや高圧ホモジナイザー、Ｘ－プレス、ボールミル、コロイドミル、ＤＹＮＯミル、超音波ホモジナイザー等の、流体せん断力や固体せん断力、磨砕を利用して可溶化する方法が好ましい。生物的処理としては、リゾチーム、ペクチナーゼ、セルラーゼ、チモリアーゼ、アルカラーゼなどの酵素を用いる方法や、細胞自身に含まれるプロテアーゼやエステラーゼなどの作用を利用する自己消化法の破砕法等が好ましい。 As the above-mentioned chemical treatment, for example, a method of solubilizing with a chemical such as an acid, an alkali, a surfactant, an organic solvent, or a cell wall synthesis inhibitor is preferable. As the physical treatment, for example, conventionally known French press, high-pressure homogenizer, X-press, ball mill, colloid mill, DYNO mill, ultrasonic homogenizer, fluid shear force, solid shear force, or grinding can be used. A solution method is preferred. As the biological treatment, a method using an enzyme such as lysozyme, pectinase, cellulase, thymolyase, and alcalase, and a crushing method of an autolysis method utilizing the action of protease or esterase contained in the cell itself are preferable.
　ＰＨＡ産生微生物の培養（ＰＨＡの産生）は、公知乃至慣用の方法に従って実施することができ、特に限定されないが、例えば、国際公開第２０１０／１１６６８１号に記載の方法により実施することができる。 The culture of PHA-producing microorganisms (production of PHA) can be carried out according to a known or commonly used method and is not particularly limited. For example, it can be carried out by the method described in International Publication No. 2010/116681.
　本発明により製造するＰＨＡ水分散液に含まれるＰＨＡは、下記一般式（１）
［－ＣＨＲ－ＣＨ２－ＣＯ－Ｏ－］　　　　　（１）
（式中、ＲはＣｎＨ２ｎ＋１で表されるアルキル基で、ｎは１以上１５以下の整数である。）
で示される繰り返し単位を含む少なくとも１種以上のＰＨＡであることが好ましい。 PHA contained in the PHA aqueous dispersion produced by the present invention has the following general formula (1):
[-CHR-CH 2 -CO-O-] (1)
(In the formula, R is an alkyl group represented by C n H 2n + 1 , and n is an integer of 1 or more and 15 or less.)
It is preferable that it is at least one or more PHA containing the repeating unit shown by.
　上記ＰＨＡは、前記一般式（１）で示される繰り返し単位を、全繰り返し単位の５０モル％以上含むものであることが好ましく、さらにその他の繰り返し構造を含んでいてもよい。特に、一般式（１）で示される繰り返し単位を、全繰り返し単位の７０モル％以上含むものであることがより好ましく、さらに好ましくは８０モル％以上である。 The PHA preferably contains the repeating unit represented by the general formula (1) in an amount of 50 mol% or more of all repeating units, and may further contain other repeating structures. In particular, it is more preferable that the repeating unit represented by the general formula (1) is contained in an amount of 70 mol% or more based on all the repeating units, and further preferably 80 mol% or more.
　上記ＰＨＡとしては、例えば、ポリ（３－ヒドロキシブチレート）（ＰＨＢ）、ポリ（３－ヒドロキシブチレート－ｃｏ－３－ヒドロキシバレレート）（ＰＨＢＶ）、〔ポリ（３－ヒドロキシブチレート－ｃｏ－３-ヒドロキシバレレート－ｃｏ－３-ヒドロキシヘキサノエート）（Ｐ３ＨＢ３ＨＶ３ＨＨ）、ポリ（３－ヒドロキシブチレート－ｃｏ－３－ヒドロキシヘキサノエート）（ＰＨＢＨ）、ポリ（３－ヒドロキシブチレート－ｃｏ－４－ヒドロキシブチレート）（Ｐ３ＨＢ４ＨＢ）、ポリ（３－ヒドロキシブチレート－ｃｏ－３－ヒドロキシオクタノエート）、ポリ（３－ヒドロキシブチレート－ｃｏ－３－ヒドロキシオクタデカノエート）、ポリ（３－ヒドロキシブチレート－ｃｏ－３－ヒドロキシ－４－メチルバレレート）（Ｐ３ＨＢ３Ｈ４ＭＶ）等が挙げられる。中でも特に、工業的生産が比較的容易であることから、ＰＨＢ、ＰＨＢＶ、Ｐ３ＨＢ３ＨＶ３ＨＨ、ＰＨＢＨ、Ｐ３ＨＢ４ＨＢが好ましい。 Examples of the PHA include poly (3-hydroxybutyrate) (PHB), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and [poly (3-hydroxybutyrate-co- 3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly (3-hydroxybutyrate-co- 4-hydroxybutyrate) (P3HB4HB), poly (3-hydroxybutyrate-co-3-hydroxyoctanoate), poly (3-hydroxybutyrate-co-3-hydroxyoctadecanoate), poly (3 -Hydroxybutyrate-co-3-hydroxy-4-methylvalerate) (P3HB3H4MV) and the like. Of these, PHB, PHBV, P3HB3HV3HH, PHBH, and P3HB4HB are particularly preferable because they are relatively easily industrially produced.
　上記ＰＨＡとして、３－ヒドロキシブチレートの繰り返し構造単位を有するものを用いる場合、当該繰り返し構造単位の平均組成比は、ＰＨＡの柔軟性と強度のバランスの観点から、８０～９９モル％であることが好ましい。 When the PHA having a repeating structural unit of 3-hydroxybutyrate is used, the average composition ratio of the repeating structural unit is 80 to 99 mol% from the viewpoint of the balance between flexibility and strength of PHA. Is preferred.
　本発明で製造するＰＨＡ水分散液は、ＰＨＡとして一種を単独で有するものであってもよいし、二種以上を組み合わせて有するものであってもよい。 The PHA aqueous dispersion produced by the present invention may have one PHA alone or may have two or more PHA in combination.
　工程（ａ）における濃縮対象としてのＰＨＡ水分散液におけるＰＨＡ粒子のメディアン径は、１～５μｍであり、好ましくは２～５μｍである。なお、メディアン径は、レーザー回折法により測定される。なお、ＰＨＡ水分散液におけるＰＨＡ粒子のメディアン径は、例えば、ＰＨＡをＰＨＡ生産菌の培養により製造する場合には、その培養時間を制御することにより調整できる。例えば、培養時間を長くすれば、メディアン径も大きくなる傾向がある。 The median diameter of PHA particles in the PHA aqueous dispersion to be concentrated in the step (a) is 1 to 5 μm, preferably 2 to 5 μm. The median diameter is measured by the laser diffraction method. The median diameter of PHA particles in the PHA aqueous dispersion can be adjusted by controlling the culture time, for example, when PHA is produced by culturing PHA-producing bacteria. For example, if the culture time is lengthened, the median diameter tends to increase.
　工程（ａ）における濃縮対象としてのＰＨＡ水分散液の固形分濃度は、５０重量％未満であり、本発明の効果をより効果的に享受する観点で、好ましくは４５重量％未満、より好ましくは４０重量％未満、さらに好ましくは３５重量％未満である。固形分濃度の下限は特に限定されないが、生産性確保の観点で、１８重量％以上が好ましく、より好ましくは２０重量％以上、さらに好ましくは２５重量％以上である。 The solid content concentration of the PHA aqueous dispersion to be concentrated in the step (a) is less than 50% by weight, and from the viewpoint of more effectively enjoying the effect of the present invention, preferably less than 45% by weight, more preferably It is less than 40% by weight, more preferably less than 35% by weight. The lower limit of the solid content concentration is not particularly limited, but from the viewpoint of ensuring productivity, it is preferably 18% by weight or more, more preferably 20% by weight or more, and further preferably 25% by weight or more.
　工程（ａ）における濃縮対象としてのＰＨＡ水分散液は、水及びＰＨＡ粒子以外のその他の成分を含んでいてもよい。その他の成分としては、水以外の溶媒（例えば、メタノール、エタノール、エチレングリコール等のアルコール類；エチレングリコールモノメチルエーテル、エチレングリコールジメチルエーテル等のエーテル類等）、分散剤（例えば、ポリビニルアルコール（ＰＶＡ）、メチルセルロース、エチルセルロース、ヒドロキシメチルセルロース、ヒドロキシエチルセルロース、ポリアクリル酸、ポリアクリル酸ナトリウム、ポリアクリル酸カリウム、ポリメタクリル酸、ポリメタクリル酸ナトリウム等の水溶性高分子等）、界面活性剤（例えば、ドデシル硫酸ナトリウム、ドデシルベンゼンスルホン酸ナトリウム、コール酸ナトリウム、デオキシコール酸ナトリウム及びオレイン酸ナトリウム等の陰イオン界面活性剤；ポリオキシエチレンアルキルエーテルやポリオキシアルキレンアルキルエーテル等の非イオン界面活性剤）、防腐剤（例えば、過酸化水素、ソルビン酸カリウム、安息香酸ナトリウム、ヒノキチオール、パラベン等）等が挙げられる。その他の成分の含有量は適宜選択可能である。 The PHA water dispersion liquid to be concentrated in the step (a) may contain water and other components other than PHA particles. Other components include solvents other than water (for example, alcohols such as methanol, ethanol and ethylene glycol; ethers such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether), dispersants (for example, polyvinyl alcohol (PVA), Water-soluble polymers such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, polymethacrylic acid, sodium polymethacrylate, etc., surfactants (eg sodium dodecyl sulfate) , Anionic surfactants such as sodium dodecylbenzenesulfonate, sodium cholate, sodium deoxycholate and sodium oleate; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyalkylene alkyl ethers), preservatives ( For example, hydrogen peroxide, potassium sorbate, sodium benzoate, hinokitiol, paraben, etc.) and the like can be mentioned. The contents of other components can be appropriately selected.
　［工程（ａ）]
　工程（ａ）は、ＰＨＡ水分散液を管状膜内に送液して（即ち、ＰＨＡ水分散液を管状膜でろ過して）、当該水分散液を濃縮する工程である。管状膜を用いたろ過は、クロスフロー方式によるろ過（クロスフローろ過）であることが好ましい。クロスフローろ過とは、膜面と水平方向に処理液が相対速度を持つ濾過方式のことである。 [Step (a)]
Step (a) is a step of feeding the PHA aqueous dispersion into the tubular membrane (that is, filtering the PHA aqueous dispersion through the tubular membrane) and concentrating the aqueous dispersion. The filtration using the tubular membrane is preferably filtration by a cross flow method (cross flow filtration). Cross-flow filtration is a filtration method in which the treatment liquid has a relative velocity in the horizontal direction with respect to the membrane surface.
　工程（ａ）において使用される濾過膜である管状膜の平均細孔径は、０．０５～０.５μｍであり、より好ましくは０．１～０．３μｍである。管状膜の平均細孔径が０．０５μｍ未満の場合、透過流束が低くなり、工業的に使用する場合は必要な膜面積が大きくなるため、コストが増大し、好ましくない。一方、平均細孔径が０．５μｍを超える場合、ＰＨＡ粒子が細孔内に入り込み、透過流束が大幅に下がり、結果として必要な膜面積が増大する。更には、洗浄等での膜再生が困難になり、工業的に使用する場合はコストが増大するため、好ましくない。 The average pore size of the tubular membrane, which is the filtration membrane used in step (a), is 0.05 to 0.5 μm, more preferably 0.1 to 0.3 μm. If the average pore size of the tubular membrane is less than 0.05 μm, the permeation flux becomes low, and the membrane area required for industrial use becomes large, which increases costs and is not preferable. On the other hand, when the average pore diameter exceeds 0.5 μm, PHA particles enter the pores, the permeation flux is significantly reduced, and as a result, the required membrane area increases. Furthermore, it is not preferable because it becomes difficult to regenerate the film by washing and the cost increases in industrial use.
　管状膜の平均細孔径は、平均粒子径が既知の無機粒子の除去率により決定される。例えば、平均細孔径が０．２μｍの管状膜の平均細孔径測定法は以下のとおりである。平均粒子径０．１μｍのシリカ粒子に水を加え、２００ｍｇ／Ｌとしたシリカ粒子水分散液（試験液）を入口圧力０．０３ＭＰａ、液温を室温として、クロスフロー方式で管状膜内へ連続通液させることによって、シリカ粒子水分散液を３倍濃縮する。また、平均粒子径０．３μｍのシリカ粒子についても、同様の操作を行う。試験液の濁度と、３倍濃縮に達した時の濾過液と濃縮液それぞれの濁度を濁度計により測定し、次の式で除去率を算出する。除去率（％）＝（１－（濾過液濁度／（試験液濁度＋濃縮液濁度）／２））×１００。平均粒子径０．１μｍのシリカ粒子除去率が５０％以下、平均粒子径０．３μｍのシリカ粒子除去率が９５％以上であれば、管状膜の平均細孔径を０．２μｍと決定する。 The average pore size of the tubular membrane is determined by the removal rate of inorganic particles whose average particle size is known. For example, the method for measuring the average pore diameter of a tubular membrane having an average pore diameter of 0.2 μm is as follows. Water was added to silica particles having an average particle diameter of 0.1 μm, and an aqueous dispersion of silica particles (test solution) at 200 mg / L was continuously introduced into the tubular membrane by a cross flow method with an inlet pressure of 0.03 MPa and a liquid temperature of room temperature. By passing the solution, the aqueous dispersion of silica particles is concentrated three times. Further, the same operation is performed on silica particles having an average particle diameter of 0.3 μm. The turbidity of the test solution and the turbidity of each of the filtered solution and the concentrated solution when the concentration reaches 3 times are measured with a turbidimeter, and the removal rate is calculated by the following formula. Removal rate (%) = (1- (turbidity of filtrate / (turbidity of test liquid + turbidity of concentrated liquid) / 2)) × 100. If the removal rate of silica particles having an average particle size of 0.1 μm is 50% or less and the removal rate of silica particles having an average particle size of 0.3 μm is 95% or more, the average pore size of the tubular membrane is determined to be 0.2 μm.
　上記管状膜の内径は、４～１０ｍｍであり、好ましくは４～７ｍｍである。内径が４ｍｍ未満であると、濃縮により粘度が増大したＰＨＡ水分散液が管状膜内で閉塞し、濃縮が不可となる傾向があり、好ましくない。一方、内径が１０ｍｍを超えると、膜表面（膜表面に形成されるＰＨＡ粒子層表面）にかかる線速が小さくなるため、膜表面に堆積したＰＨＡ粒子層を剥離する力が弱くなり、膜上に形成されるＰＨＡ粒子層が厚くなってしまい透過流束が小さくなる、つまり、濃縮にかかる時間が増大する傾向がある。また、必要な膜モジュール数が増え、工業的に使用する場合はコストが増大するため、好ましくない。
　尚、管状膜の内径とは、管状膜の円形中空断面の内側の直径を意味する。 The inner diameter of the tubular membrane is 4 to 10 mm, preferably 4 to 7 mm. If the inner diameter is less than 4 mm, the PHA aqueous dispersion whose viscosity has increased due to concentration tends to be clogged in the tubular membrane, making concentration impossible, which is not preferable. On the other hand, when the inner diameter exceeds 10 mm, the linear velocity applied to the film surface (the surface of the PHA particle layer formed on the film surface) decreases, so the force for peeling the PHA particle layer deposited on the film surface becomes weak and The PHA particle layer formed in the above becomes thick and the permeation flux becomes small, that is, the concentration time tends to increase. In addition, the number of membrane modules required increases, and the cost increases in industrial use, which is not preferable.
The inner diameter of the tubular membrane means the inner diameter of the circular hollow cross section of the tubular membrane.
　上記管状膜（濾過膜）の材質は、特に限定されないが、例えば、ポリプロピレン、フッ素系樹脂（例えば、ポリテトラフルオロエチレン、ポリフッ化ビニリデン、ポリフッ化ビニル、四フッ化エチレン・六フッ化プロピレン共重合体、エチレン・四フッ化エチレン共重合体等）、セルロースエステル（例えば、セルロースアセテート、セルロースアセテートプロピオネート、セルロースアセテートブチレート等）、ポリスルホン系樹脂（例えば、ポリスルホン、ポリエーテルスルホン等）、ポリアクリロニトリル、ポリイミド等の樹脂；アルミナ、ムライト、ジルコニア、コージライト等の多孔質セラミックスや、ステンレス鋼等の多孔質焼結金属からなる多孔質体等の無機材料等が挙げられる。 The material of the tubular membrane (filtration membrane) is not particularly limited, but for example, polypropylene, fluororesin (eg, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene / propylene hexafluoride copolymer) Polymer, ethylene / tetrafluoroethylene copolymer, etc.), cellulose ester (eg, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, etc.), polysulfone resin (eg, polysulfone, polyether sulfone, etc.), poly Resins such as acrylonitrile and polyimide; porous ceramics such as alumina, mullite, zirconia, and cordierite; and inorganic materials such as porous bodies made of porous sintered metal such as stainless steel.
　工程（ａ）では、ＰＨＡ水分散液を管状膜内に通液することによって濃縮する。当該管状膜を用いたろ過操作は、公知乃至慣用の手順で実施できる。管状膜内に通液する回数は特に限定されず、通常は、管状膜内を何度も循環させることによって徐々に水を管状膜外に透過させて、ＰＨＡ水分散液を濃縮する。 In step (a), the PHA aqueous dispersion is concentrated by passing it through the tubular membrane. The filtration operation using the tubular membrane can be carried out by a known or common procedure. The number of times the liquid is passed through the tubular membrane is not particularly limited, and usually, the PHA aqueous dispersion is concentrated by allowing the water to gradually permeate out of the tubular membrane by circulating the water inside the tubular membrane many times.
　ＰＨＡ水分散液を管状膜に供給する場合の膜間差圧は、特に限定されないが、０．００１～０．１ＭＰａが好ましく、より好ましくは０．０１～０．１ＭＰａである。膜間差圧が０．００１ＭＰａ未満の場合、濾過に必要な推進力が不足して、濾過が行われないため、好ましくない。一方、膜間差圧が０．１ＭＰａを超える場合、圧力による膜の劣化が起こりやすい傾向があるため、好ましくない。 The transmembrane pressure difference when supplying the PHA aqueous dispersion to the tubular membrane is not particularly limited, but is preferably 0.001 to 0.1 MPa, and more preferably 0.01 to 0.1 MPa. When the transmembrane pressure difference is less than 0.001 MPa, the propulsive force required for filtration is insufficient and filtration is not performed, which is not preferable. On the other hand, when the transmembrane pressure difference exceeds 0.1 MPa, deterioration of the membrane due to the pressure tends to occur, which is not preferable.
　ＰＨＡ水分散液を濃縮するときの線速度（管状膜内に通液する線速度）は、特に限定されないが、１～５ｍ／ｓが好ましく、より好ましくは１．５～４ｍ／ｓ、さらに好ましくは２～４ｍ／ｓである。１ｍ／ｓ未満の場合、ＰＨＡによる流路閉塞が発生するため、濃縮が困難になり、好ましくない。一方、５ｍ／ｓを超える場合、せん断による膜の劣化を引き起こす傾向があるため、好ましくない。なお、管状膜が樹脂製（例えば、ポリプロピレン製）の場合には、耐久性の観点で、線速度の上限は３ｍ／ｓ以下とすることが好ましい。 The linear velocity at the time of concentrating the PHA aqueous dispersion (the linear velocity passing through the tubular membrane) is not particularly limited, but is preferably 1 to 5 m / s, more preferably 1.5 to 4 m / s, and further preferably Is 2 to 4 m / s. When it is less than 1 m / s, the flow path is blocked by PHA, which makes concentration difficult, which is not preferable. On the other hand, if it exceeds 5 m / s, it tends to cause deterioration of the film due to shearing, which is not preferable. When the tubular film is made of resin (for example, polypropylene), the upper limit of the linear velocity is preferably 3 m / s or less from the viewpoint of durability.
　ＰＨＡ水分散液を濃縮するときの圧力損失は、特に限定されないが、固形分濃度を５０重量％に濃縮した際の圧力損失が０．１ＭＰａ以下であることが好ましく、より好ましくは０．０５ＭＰａ以下である。０．１ＭＰａを超える場合、圧力による膜の劣化を引き起こす傾向があるため、好ましくない。 The pressure loss when concentrating the PHA aqueous dispersion is not particularly limited, but the pressure loss when concentrating the solid content concentration to 50% by weight is preferably 0.1 MPa or less, more preferably 0.05 MPa or less. Is. When it exceeds 0.1 MPa, the pressure tends to cause deterioration of the film, which is not preferable.
　ＰＨＡ水分散液を濃縮するときの透過流束は、特に限定されないが、固形分濃度を５０重量％に濃縮した際の透過流束が１０ｋｇ／ｍ２・ｈ以上となることが好ましく、より好ましくは２０ｋｇ／ｍ２・ｈ以上である。１０ｋｇ／ｍ２・ｈ未満の場合、工業的に利用するためには広大な膜面積を要し、コストが増大するため、好ましくない。 The permeation flux at the time of concentrating the PHA aqueous dispersion is not particularly limited, but the permeation flux at the time of concentrating the solid content concentration to 50% by weight is preferably 10 kg / m 2 · h or more, and more preferably Is 20 kg / m 2 · h or more. If it is less than 10 kg / m 2 · h, a large membrane area is required for industrial use, and the cost increases, which is not preferable.
　工程（ａ）を経て、濃縮されたＰＨＡ水分散液が得られる。工程（ａ）で得られるＰＨＡ水分散液の固形分濃度は５０重量％以上であり、好ましくは５２重量％以上、より好ましくは５４重量％以上である。上限は特に限定されないが、ＰＨＡ水分散液の流動性確保の観点で、６５重量％以下が好ましく、より好ましくは６０重量％以下である。 After the step (a), a concentrated PHA aqueous dispersion is obtained. The solid content concentration of the PHA aqueous dispersion obtained in step (a) is 50% by weight or more, preferably 52% by weight or more, more preferably 54% by weight or more. The upper limit is not particularly limited, but from the viewpoint of securing the fluidity of the PHA aqueous dispersion, it is preferably 65% by weight or less, more preferably 60% by weight or less.
　本発明のＰＨＡ水分散液の製造方法は、上述のように、工程（ａ）以外の他の工程（例えば、工程（ａ）により得られたＰＨＡ水分散液に添加剤（例えば、上述のその他の成分等）を添加する工程、水の一部を除去する工程等）を含んでいてもよい。また、工程（ａ）の前に、ＰＨＡ生産菌を培養する工程や、当該培養により得られたＰＨＡ含有菌体からＰＨＡ水分散液を得る工程（例えば、上述の分離精製処理を実施する工程等）を含んでいてもよい。 As described above, the method for producing a PHA water dispersion according to the present invention includes an additive (for example, the above-mentioned other components to the PHA water dispersion obtained in the step (a) other than the step (a). Component, etc.), a step of removing a part of water, etc.) may be included. Further, before the step (a), a step of culturing a PHA-producing bacterium, a step of obtaining a PHA aqueous dispersion from PHA-containing microbial cells obtained by the culturing (for example, a step of performing the above-mentioned separation and purification treatment, etc. ) May be included.
　本発明のＰＨＡ水分散液の製造方法により得られるＰＨＡ水分散液は、例えば、フィルムやコーティング等の各種成形体の原料として使用することができる。また、乾燥させて水を除去することにより、固体状のＰＨＡを得ることもできる。 The PHA aqueous dispersion obtained by the method for producing a PHA aqueous dispersion of the present invention can be used as a raw material for various molded products such as films and coatings. In addition, a solid PHA can be obtained by drying and removing water.
　以下、実施例により本発明をより具体的に説明するが、本発明はこれらの実施例により限定されるものではない。 Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.
　（ＰＨＡ水分散液の固形分濃度測定法）
　重量を測定したＰＨＡ水分散液を１４０℃で加熱し、水分を蒸発させ、その減少重量を測定することで、ＰＨＡ水分散液の固形分濃度を求めた。 (Method for measuring solid content concentration of PHA aqueous dispersion)
The weight-measured PHA aqueous dispersion was heated at 140 ° C. to evaporate water, and the weight reduction was measured to determine the solid content concentration of the PHA water dispersion.
　（実施例１）
　国際公開第２０１０／１１６６８１号の実施例１に記載の方法でラルストニア・ユートロファＫＮＫ－００５株を培養し、ポリ（３－ヒドロキシブチレート－コ－３－ヒドロキシヘキサノエート）（ＰＨＢＨ）を含有する菌体培養液を作製した。次に、上記で得られた菌体培養液を内温６０～８０℃で２０分間加熱・攪拌処理し、滅菌処理を行った。上記で得られた滅菌済みの菌体培養液に対して、０.２重量％のドデシル硫酸ナトリウムを添加した。さらに、ｐＨが１１.０になるように水酸化ナトリウム水溶液を添加した後、５０℃で１時間保温した。その後、高圧破砕機（ニロソアビ社製高圧ホモジナイザーモデルＰＡ２Ｋ型）を用いて、４５０～５５０ｋｇｆ／ｃｍ２の圧力で高圧破砕を行った。上記で得られた高圧破砕後の破砕液に対して等量の蒸留水を添加した。これを遠心分離した後、上清を除去して２倍濃縮した。この濃縮したＰＨＡ水懸濁液に、除去した上清と同量の水酸化ナトリウム水溶液（ｐＨ１１）を添加して遠心分離し、上清を除去してから再度水を添加して懸濁させ、０.２重量％のドデシル硫酸ナトリウムと、ＰＨＡの１／１００重量のプロテアーゼ（ノボザイム社、エスペラーゼ）を添加し、ｐＨ１０で５０℃に保持したまま、２時間攪拌した。その後、遠心分離により上清を除去して４倍濃縮した。さらに水を添加することで、ＰＨＢＨ粒子のメディアン径が２μｍであり、固形分濃度が１８重量％（ＰＨＢＨ粒子の含有量：１８０ｇ／Ｌ）であるＰＨＢＨ水分散液を得た。 (Example 1)
The Ralstonia eutropha KNK-005 strain was cultured by the method described in Example 1 of WO 2010/116681 and contained poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). A cell culture solution was prepared. Next, the bacterial cell culture solution obtained above was sterilized by heating and stirring at an internal temperature of 60 to 80 ° C. for 20 minutes. 0.2% by weight of sodium dodecyl sulfate was added to the sterilized cell culture solution obtained above. Further, an aqueous sodium hydroxide solution was added to adjust the pH to 11.0, and then the mixture was kept at 50 ° C. for 1 hour. Then, high-pressure crushing was performed using a high-pressure crusher (high-pressure homogenizer model PA2K type manufactured by Niro Soavi Co., Ltd.) at a pressure of 450 to 550 kgf / cm 2 . An equal amount of distilled water was added to the crushed liquid obtained after high-pressure crushing. After centrifuging this, the supernatant was removed and concentrated twice. To this concentrated PHA water suspension, the same amount of sodium hydroxide aqueous solution (pH 11) as the removed supernatant was added and centrifuged, and after removing the supernatant, water was added again to suspend. 0.2 wt% sodium dodecyl sulfate and 1/100 wt PHA protease (Novozymes, Esperase) were added, and the mixture was stirred for 2 hours while maintaining at pH 10 at 50 ° C. Then, the supernatant was removed by centrifugation and the solution was concentrated 4 times. By further adding water, a PHBH aqueous dispersion having a median diameter of PHBH particles of 2 μm and a solid content concentration of 18% by weight (PHBH particle content: 180 g / L) was obtained.
　前記ＰＨＢＨ水分散液をタンク３に投入し、図３に概略図を示す装置を用いて、平均細孔径０．２μｍ、内径５．５ｍｍのポリプロピレン製の管状膜（ＭＩＣＲＯＤＹＮＲ　ＭＤ０２０ＴＰ２Ｎ）に線速度２ｍ／ｓで循環供給（送液）し、濃縮を実施した。図３に示すように、ろ液を管状膜１から系外に除くことによってＰＨＡ水分散液が濃縮される。濃縮時の圧力損失、及び、濃縮後のＰＨＡ水分散液の固形分濃度を測定し、それらの結果を比較例１の結果と併せて図１に示す。これより、実施例１では、圧力損失の大幅な増大がなく、圧力損失を５０ｋＰａ以下とすることができ、低い圧力を維持したまま固形分濃度５０重量％以上への濃縮を達成できた。
　尚、圧力損失は、図３の管状膜１の入口および出口に設置された圧力計５、５’を用いて入口圧と出口圧を測定し、入口圧から出口圧を減じて算出した。
圧力損失＝（入口圧）―（出口圧）
　また、固形分濃度は、ＰＨＡ水分散液の重量を測定後、そのＰＨＡ水分散液から水分を除去した後のＰＨＡの重量を測定し、下記式により算出した。
　固形分濃度（重量％）＝（ＰＨＡ重量）／（ＰＨＡ水分散液重量）×１００ The charged with PHBH aqueous dispersion tank 3, by using the apparatus schematically showing in FIG. 3, an average pore diameter 0.2 [mu] m, polypropylene tubular membrane having an inner diameter of 5.5mm (MICRODYN R MD020TP2N) to the linear velocity 2m The solution was circulated and supplied (delivered) at / s for concentration. As shown in FIG. 3, the PHA aqueous dispersion is concentrated by removing the filtrate from the tubular membrane 1 outside the system. The pressure loss during concentration and the solid content concentration of the PHA aqueous dispersion after concentration were measured, and the results are shown in FIG. 1 together with the result of Comparative Example 1. From this, in Example 1, the pressure loss was not significantly increased, the pressure loss could be 50 kPa or less, and the concentration to the solid content concentration of 50% by weight or more could be achieved while maintaining the low pressure.
The pressure loss was calculated by measuring the inlet pressure and the outlet pressure using pressure gauges 5 and 5 ′ installed at the inlet and the outlet of the tubular membrane 1 of FIG. 3, and subtracting the outlet pressure from the inlet pressure.
Pressure loss = (inlet pressure)-(outlet pressure)
The solid content concentration was calculated by the following formula after measuring the weight of the PHA aqueous dispersion and then measuring the weight of PHA after removing water from the PHA aqueous dispersion.
Solid content concentration (wt%) = (PHA weight) / (PHA aqueous dispersion weight) × 100
　（比較例１）
　実施例１と同様の方法で得られた菌体培養液を用いて、最後に添加する水の量を変更したこと以外は実施例１と同様にして、ＰＨＢＨ粒子のメディアン径が２μｍであり、固形分濃度が１６重量％（ＰＨＢＨ粒子の含有量：１６０ｇ／Ｌ）であるＰＨＢＨ水分散液を得た。当該ＰＨＢＨ水分散液をタンク３に投入し、平均細孔径０．２μｍ、内径１．８ｍｍのポリプロピレン製の中空糸膜（ＭＩＣＲＯＤＹＮＲ　ＭＤ０２０ＣＰ２Ｎ）に線速度２ｍ／ｓで循環供給（送液）し、濃縮を実施した。濃縮時の圧力損失、及び、濃縮後のＰＨＡ水分散液の固形分濃度を測定し、それらの結果を図１に示す。比較例１では、圧力損失が増大し、５０ｋＰａを超過したため、低い圧力を維持しながら固形分濃度５０重量％以上への濃縮を達成できなかった。 (Comparative Example 1)
The median diameter of PHBH particles was 2 μm in the same manner as in Example 1 except that the amount of water added last was changed using the cell culture solution obtained in the same manner as in Example 1. A PHBH aqueous dispersion having a solid content concentration of 16% by weight (PHBH particle content: 160 g / L) was obtained. The PHBH aqueous dispersion was placed in the tank 3, and circulated and supplied (liquid transfer) to a polypropylene hollow fiber membrane (MICRODYN R MD020CP2N) having an average pore diameter of 0.2 μm and an inner diameter of 1.8 mm at a linear velocity of 2 m / s, Concentration was carried out. The pressure loss during concentration and the solid content concentration of the PHA aqueous dispersion after concentration were measured, and the results are shown in FIG. In Comparative Example 1, the pressure loss increased and exceeded 50 kPa, so that it was not possible to achieve concentration to a solid content concentration of 50% by weight or more while maintaining a low pressure.
　（実施例２）
　実施例１と同様の方法で得られた菌体培養液を用いて、実施例１と同様にして、ＰＨＢＨ粒子のメディアン径が２μｍであり、固形分濃度が１８重量％（ＰＨＢＨ粒子の含有量：１８０ｇ／Ｌ）であるＰＨＢＨ水分散液を得た。当該ＰＨＢＨ水分散液をタンク３に投入し、平均細孔径０．２μｍ、内径５．５ｍｍのポリプロピレン製の管状膜（ＭＩＣＲＯＤＹＮＲ　ＭＤ０２０ＴＰ２Ｎ）に線速度２ｍ／ｓで循環供給（送液）し、濃縮を実施した。濃縮時の透過流束、及び、濃縮後のＰＨＡ水分散液の固形分濃度を測定し、それらの結果を比較例２の結果と併せて図２に示す。これより、実施例２では、透過流束を１０ｋｇ／ｍ２・ｈ以上で維持したまま、固形分濃度５０重量％以上への濃縮を達成できた。
　尚、透過流束は、透過液（ＰＨＡ水分散液）を１分間測量し、膜面積で除することにより算出した。また、固形分濃度は、前述した方法及び式により算出した。 (Example 2)
Using the bacterial cell culture solution obtained by the same method as in Example 1, the median diameter of PHBH particles was 2 μm and the solid content concentration was 18% by weight (the content of PHBH particles was the same as in Example 1). : 180 g / L) to obtain a PHBH aqueous dispersion. The PHBH aqueous dispersion is charged into a tank 3, and is circulated and supplied (liquid transfer) at a linear velocity of 2 m / s to a polypropylene tubular membrane (MICRODYN R MD020TP2N) having an average pore diameter of 0.2 μm and an inner diameter of 5.5 mm, and concentrated. Was carried out. The permeation flux at the time of concentration and the solid content concentration of the PHA aqueous dispersion after concentration were measured, and the results are shown together with the result of Comparative Example 2 in FIG. From this, in Example 2, it was possible to achieve concentration to a solid content concentration of 50% by weight or more while maintaining the permeation flux at 10 kg / m 2 · h or more.
The permeation flux was calculated by measuring the permeation liquid (PHA water dispersion liquid) for 1 minute and dividing it by the membrane area. Further, the solid content concentration was calculated by the above-described method and formula.
　（比較例２）
　実施例１と同様の方法で得られた菌体培養液を用いて、最後に添加する水の量を変更したこと以外は実施例１と同様にして、ＰＨＢＨ粒子のメディアン径が２μｍであり、固形分濃度が１０重量％（ＰＨＢＨ粒子の含有量：１００ｇ／Ｌ）であるＰＨＢＨ水分散液を得た。当該ＰＨＢＨ水分散液をタンク３に投入し、平均細孔径１．０μｍ、内径５ｍｍのポリエチレン製の管状膜（ＳＥＰＲＯＤＹＮＲ　ＳＥ０２０ＴＰ１Ｎ）に線速度２ｍ／ｓで循環供給（送液）し、濃縮を実施した。濃縮時の透過流束、及び、濃縮後のＰＨＡ水分散液の固形分濃度を測定し、それらの結果を図２に示す。比較例２では、透過流束が大幅に低下し、固形分濃度２０重量％を超えた時点で１０ｋｇ／ｍ２・ｈ未満になったため、透過流束を１０ｋｇ／ｍ２・ｈ以上で維持しながら固形分濃度５０重量％以上への濃縮を達成できなかった。 (Comparative example 2)
The median diameter of PHBH particles was 2 μm in the same manner as in Example 1 except that the amount of water added last was changed using the cell culture solution obtained in the same manner as in Example 1. A PHBH aqueous dispersion having a solid content concentration of 10% by weight (PHBH particle content: 100 g / L) was obtained. Put the PHBH aqueous dispersion tank 3, and an average pore diameter 1.0 .mu.m, circulated and supplied into a polyethylene tubular film having an inner diameter of 5mm (SEPRODYN R SE020TP1N) at a linear velocity of 2m / s (liquid feed), carried out concentrated did. The permeation flux at the time of concentration and the solid content concentration of the PHA aqueous dispersion after concentration were measured, and the results are shown in FIG. In Comparative Example 2, the permeation flux was significantly reduced and became less than 10 kg / m 2 · h when the solid content concentration exceeded 20% by weight. Therefore, the permeation flux was maintained at 10 kg / m 2 · h or more. However, concentration to a solid content concentration of 50% by weight or more could not be achieved.
１　　管状膜
２　　ポンプ
３　　タンク（ＰＨＡ水分散液が入ったタンク）
４　　攪拌機
５、５’　　圧力計
  1 Tubular membrane 2 Pump 3 Tank (PHA water dispersion liquid tank)
4 Stirrer 5, 5 'Pressure gauge

Claims (6)

  1. 　ポリヒドロキシアルカノエート水分散液の製造方法であって、ポリヒドロキシアルカノエート粒子のメディアン径が１～５μｍであり固形分濃度が５０重量％未満のポリヒドロキシアルカノエート水分散液を、内径４～１０ｍｍ、平均細孔径０．０５～０．５μｍの管状膜内に送液して固形分濃度を５０重量％以上に濃縮する工程を含む、ポリヒドロキシアルカノエート水分散液の製造方法。 A method for producing an aqueous dispersion of polyhydroxyalkanoate, wherein an aqueous dispersion of polyhydroxyalkanoate having a median diameter of polyhydroxyalkanoate particles of 1 to 5 μm and a solid content concentration of less than 50% by weight has an inner diameter of 4 to 10 mm. A method for producing an aqueous dispersion of polyhydroxyalkanoate, which comprises the step of feeding the solution into a tubular membrane having an average pore size of 0.05 to 0.5 μm to concentrate the solid content concentration to 50% by weight or more.
  2. 　前記管状膜内に送液して濃縮する前のポリヒドロキシアルカノエート水分散液の固形分濃度が４５重量％未満である、請求項１に記載のポリヒドロキシアルカノエート水分散液の製造方法。 The method for producing a polyhydroxyalkanoate aqueous dispersion according to claim 1, wherein the polyhydroxyalkanoate aqueous dispersion has a solid content concentration of less than 45% by weight before being fed into the tubular membrane and concentrated.
  3. 　前記管状膜内に送液して濃縮する前のポリヒドロキシアルカノエート水分散液の固形分濃度が４０重量％未満である、請求項１に記載のポリヒドロキシアルカノエート水分散液の製造方法。 The method for producing a polyhydroxyalkanoate aqueous dispersion according to claim 1, wherein the polyhydroxyalkanoate aqueous dispersion has a solid content concentration of less than 40% by weight before being sent to the tubular membrane for concentration.
  4. 　前記管状膜内に送液するポリヒドロキシアルカノエート水分散液の線速度が１～３ｍ／ｓである、請求項１～３のいずれか１項に記載のポリヒドロキシアルカノエート水分散液の製造方法。 The method for producing an aqueous polyhydroxyalkanoate dispersion according to any one of claims 1 to 3, wherein the linear velocity of the aqueous polyhydroxyalkanoate dispersion sent into the tubular membrane is 1 to 3 m / s. ..
  5. 　前記工程の前に、ポリヒドロキシアルカノエート生産菌の培養により得られたポリヒドロキシアルカノエート含有菌体からポリヒドロキシアルカノエート水分散液を得る工程をさらに含む、請求項１～４のいずれか１項に記載のポリヒドロキシアルカノエート水分散液の製造方法。 5. The method according to claim 1, further comprising a step of obtaining an aqueous dispersion of polyhydroxyalkanoate from the polyhydroxyalkanoate-containing bacterium obtained by culturing the polyhydroxyalkanoate-producing bacterium before the step. The method for producing an aqueous dispersion of polyhydroxyalkanoate according to 1.
  6. 　前記管状膜がポリプロピレン製の管状膜である、請求項１～５のいずれか１項に記載のポリヒドロキシアルカノエート水分散液の製造方法。
          The method for producing an aqueous polyhydroxyalkanoate dispersion according to any one of claims 1 to 5, wherein the tubular membrane is a polypropylene tubular membrane.
PCT/JP2019/042634 2018-11-12 2019-10-30 Method for producing aqueous polyhydroxyalkanoate dispersion WO2020100598A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021079750A1 (en) * 2019-10-25 2021-04-29 株式会社カネカ Method for producing aqueous polymer dispersion

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005161113A (en) * 2003-11-28 2005-06-23 Yuasa Corp Membrane separator
JP2008086991A (en) * 2006-09-07 2008-04-17 Nikko Co Circulation type method and apparatus for treating human waste
WO2010067541A1 (en) * 2008-12-09 2010-06-17 株式会社カネカ Method for producing poly-3-hydroxyalkanoate
JP2016524926A (en) * 2013-07-30 2016-08-22 ビオ オン ソシエタ ペル アチオニ Method for recovering and purifying polyhydroxyalkanoates from cell cultures

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005161113A (en) * 2003-11-28 2005-06-23 Yuasa Corp Membrane separator
JP2008086991A (en) * 2006-09-07 2008-04-17 Nikko Co Circulation type method and apparatus for treating human waste
WO2010067541A1 (en) * 2008-12-09 2010-06-17 株式会社カネカ Method for producing poly-3-hydroxyalkanoate
JP2016524926A (en) * 2013-07-30 2016-08-22 ビオ オン ソシエタ ペル アチオニ Method for recovering and purifying polyhydroxyalkanoates from cell cultures

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
LENNTECH B.V.: "The art to clear Solutions", MICRODYN NADIR, 29 August 2017 (2017-08-29), pages 1 - 36, XP055707228, Retrieved from the Internet <URL:https://web.archive.org/web/20170829003335/https://www.lenntech.com/Data-sheets/Microdyn-Product-catalogue-L.pdf> [retrieved on 20200107] *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021079750A1 (en) * 2019-10-25 2021-04-29 株式会社カネカ Method for producing aqueous polymer dispersion

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