阅读说明：本技术 利用色谱吸附法对聚羟基脂肪酸酯发酵液处理的方法和处理系统以及所得发酵废液的应用 (Method and system for treating polyhydroxyalkanoate fermentation liquor by using chromatographic adsorption method and application of obtained fermentation waste liquor ) 是由 佟毅 李义 郭元亨 田芳 李大勇 刘海军 彭超 陈博 杨凯 于 2020-04-29 设计创作，主要内容包括：本发明涉及聚羟基脂肪酸酯的制备领域,具体涉及利用色谱吸附法对聚羟基脂肪酸酯发酵液处理的方法和处理系统以及所得发酵废液的应用。该方法包括：将聚羟基脂肪酸酯的发酵液进行固液分离,得到菌体沉淀和发酵清液；然后将所述发酵清液在色谱柱中进行色谱吸附处理,得到处理后的发酵清液。本发明的方法和系统能够有效地降低PHA的生产成本,且发酵清液经处理回用后能够有效保障PHA发酵菌种的发酵效率和PHA得率。(The invention relates to the field of preparation of polyhydroxyalkanoate, in particular to a method and a system for treating polyhydroxyalkanoate fermentation liquor by using a chromatographic adsorption method and application of the obtained fermentation waste liquor. The method comprises the following steps: carrying out solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain thallus sediment and fermentation clear liquid; and then carrying out chromatographic adsorption treatment on the fermentation clear liquid in a chromatographic column to obtain the treated fermentation clear liquid. The method and the system can effectively reduce the production cost of PHA, and the fermentation efficiency and the PHA yield of PHA fermentation strains can be effectively guaranteed after the fermentation clear liquid is treated and recycled.)

1. A method for processing polyhydroxyalkanoate fermentation liquor, which is characterized by comprising the following steps: carrying out solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain thallus sediment and fermentation clear liquid; and then carrying out chromatographic adsorption treatment on the fermentation clear liquid in a chromatographic column to obtain the treated fermentation clear liquid.

2. The method of claim 1, wherein the chromatography column is one or more of a non-polar macroporous adsorbent resin chromatography column, a weakly polar macroporous adsorbent resin chromatography column, a strongly polar macroporous adsorbent resin chromatography column, and an ion exchange resin chromatography column.

3. The method of claim 2, wherein the chromatography column is an ion exchange resin chromatography column.

4. The method of claim 3, wherein the ion exchange resin chromatography column is an anion exchange chromatography column;

preferably, the anion exchange chromatography column is a strongly basic anion exchange chromatography column.

5. The method according to any one of claims 1 to 4, wherein the temperature of the chromatographic adsorption treatment is 0 to 40 ℃, and the flow speed of the fermentation liquor in the chromatographic column is 1 to 3 BV/h.

6. The method according to claim 1, wherein the solid-liquid separation conditions are such that the water content of the bacterial pellet is 40-90 wt%;

preferably, the solid-liquid separation comprises a first solid-liquid separation and a second solid-liquid separation, wherein the fermentation clear liquid comprises a liquid phase obtained by the first solid-liquid separation and a liquid phase obtained by the second solid-liquid separation;

more preferably, a disc-type centrifuge is used for the primary solid-liquid separation, and a belt type vacuum filter is used for the secondary solid-liquid separation;

further preferably, the method further comprises the step of performing third solid-liquid separation on the fermented clear liquid before performing chromatographic adsorption treatment on the fermented clear liquid, wherein the third solid-liquid separation is plate-frame filtration.

7. Use of a treated fermentation broth obtained by the treatment process of any one of claims 1-6 in fermentation of PHA.

8. A system for processing polyhydroxyalkanoate fermentation broth, the system comprising:

the solid-liquid separation unit is used for carrying out solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain thallus sediment and fermentation clear liquor;

and the chromatographic adsorption unit is used for receiving the fermentation clear liquid and carrying out chromatographic adsorption treatment on the fermentation clear liquid in a chromatographic column to obtain the treated fermentation clear liquid.

9. The system of claim 8, wherein the solid-liquid separation unit comprises a first solid-liquid separation zone for performing a first solid-liquid separation on the fermentation broth of polyhydroxyalkanoate to obtain a first fermentation supernatant and a first bacterial pellet; and a second solid-liquid separation zone, which is used for carrying out second solid-liquid separation on the first thallus precipitate to obtain a second fermentation clear liquid and a second thallus precipitate;

preferably, a disc-type centrifuge is arranged in the first solid-liquid separation zone, and a belt type vacuum filter is arranged in the second solid-liquid separation zone;

preferably, the first solid-liquid separation unit is further provided with a third solid-liquid separation zone for performing third solid-liquid separation on the fermented clear liquid before conveying the fermented clear liquid to the chromatographic adsorption unit, wherein a plate-and-frame filter is arranged in the third solid-liquid separation zone.

10. The method according to claim 8 or 9, wherein a chromatographic column is arranged in the chromatographic adsorption unit, and the chromatographic column is one or more of a non-polar macroporous adsorption resin chromatographic column, a weak-polar macroporous adsorption resin chromatographic column, a strong-polar macroporous adsorption resin chromatographic column and an ion exchange resin chromatographic column;

preferably, the chromatographic column is an ion exchange resin chromatographic column;

further preferably, the ion exchange resin chromatographic column is an anion exchange chromatographic column;

still further preferably, the anion exchange chromatography column is a strongly basic anion exchange chromatography column;

preferably, the system also comprises a polyhydroxyalkanoate fermentation unit which is connected with the chromatographic adsorption unit and is used for fermenting polyhydroxyalkanoate by using the treated fermentation clear liquid.

Technical Field

The invention relates to the field of preparation of polyhydroxyalkanoate, in particular to a method and a system for treating polyhydroxyalkanoate fermentation liquor by using a chromatographic adsorption method, and application of the obtained treated fermentation clear liquid in PHA fermentation.

Background

Polyhydroxyalkanoates (PHAs) are a generic name for a class of high molecular polyesters that are synthesized entirely by microorganisms. PHA is biodegradable and biocompatible and thus is considered as an environmentally friendly material, contributing to solving the increasingly serious problem of environmental pollution. Although the use of PHA can effectively avoid the environmental damage caused by petrochemical plastics, the production cost of such environment-friendly bioplastic is high, and the commercialization development of PHA is always limited by the high production cost, and researchers have been working on solving the problems of high substrate and sterilization costs, low yield, and the like, in order to reduce the cost.

The selection of high-quality and high-yield chassis bacteria which are not easy to be infected with bacteria is an effective method for improving quality and reducing cost, halophilic bacteria are high-yield strains with good properties and bred in recent years, and although the production cost of PHA is reduced to a certain extent, the fermentation process of the halophilic bacteria needs a high-concentration salt environment. The use of large amounts of inorganic salts leads, on the one hand, to high production costs, and, on the other hand, to the problem that the resulting high-salt waste water is disposed of at great cost.

Disclosure of Invention

The invention aims to overcome the defect of high PHA generation cost in the prior art, and provides a method and a system for treating polyhydroxyalkanoate fermentation liquor by using a chromatographic adsorption method and application of the obtained fermentation waste liquor.

The inventor of the invention finds in the research process that when the halophilic bacteria are used for PHA fermentation, if the inorganic salt added into PHA fermentation liquor can not be reused in the fermentation process, the cost of auxiliary materials is increased, and a large amount of high-salt wastewater is generated, thereby causing high wastewater treatment cost. Therefore, the recovery and utilization of inorganic salts in the fermentation broth has a crucial influence on the PHA industrialization, and if the produced high-salt wastewater is directly fermented and utilized repeatedly, the fermentation wastewater contains insoluble bacterial fragments, denatured proteins, cytotoxins, pigments and other substances which are difficult to be utilized, so that the system viscosity is increased, and the dissolved oxygen and mass transfer are deteriorated, thereby affecting the fermentation efficiency of the fermentation strains. Meanwhile, with the recycling of the fermentation waste liquid, the continuous accumulation of the substances can cause certain difficulty in subsequent separation, thereby reducing the yield and the purity of the PHA. The inventor of the invention further discovers in the research process that the generated high-salt wastewater is subjected to chromatographic adsorption treatment and then the high-salt wastewater treated in the way is recycled, so that the increase of the cost of auxiliary materials and the wastewater treatment cost in the fermentation process are reduced, the fermentation efficiency of fermentation strains can be effectively ensured, and the PHA yield is ensured.

Based on the above research results, the present invention provides a method for processing polyhydroxyalkanoate fermentation broth, comprising: carrying out solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain thallus sediment and fermentation clear liquid; and then carrying out chromatographic adsorption treatment on the fermentation clear liquid in a chromatographic column to obtain the treated fermentation clear liquid.

In a second aspect, the invention provides the use of the treated fermentation broth obtained by the treatment method as described above in PHA fermentation.

In a third aspect of the present invention, there is provided a system for treating a polyhydroxyalkanoate fermentation broth, the system comprising:

the solid-liquid separation unit is used for carrying out solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain thallus sediment and fermentation clear liquor;

and the chromatographic adsorption unit is used for receiving the fermentation clear liquid and carrying out chromatographic adsorption treatment on the fermentation clear liquid in a chromatographic column to obtain the treated fermentation clear liquid.

According to the method, most of organic impurities harmful to PHA fermentation thalli can be separated from the fermentation waste liquid by performing chromatographic adsorption separation treatment on the fermentation clear liquid, so that the treated fermentation waste liquid can be reused in the next batch of fermentation production, the auxiliary material cost can be reduced, the treatment amount of high-salt waste water can be reduced, the discharge of three wastes is reduced, and meanwhile, the chromatographic column can be repeatedly used after being regenerated, so that the method provided by the invention is a low-cost and high-efficiency treatment method. In addition, the invention can also effectively ensure the fermentation efficiency of the fermentation strain, thereby ensuring the PHA yield.

Under the preferable condition of the invention, the specific chromatographic separation medium and chromatographic separation conditions are selected, so that the production cost of PHA can be further reduced, and the fermentation efficiency and PHA yield of PHA fermentation strains can be guaranteed.

In the preferable situation of the invention, the PHA fermentation liquor is subjected to solid-liquid separation for three times, a disc-type centrifuge is used for the first solid-liquid separation, a belt-type vacuum filter is used for the second solid-liquid separation, and the obtained clear liquid is subjected to solid-liquid separation for the third time by using a plate-frame filter, so that the high-salinity wastewater can be effectively separated, and the production cost of PHA is further reduced.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In a first aspect, the present invention provides a method for treating a polyhydroxyalkanoate fermentation broth, the method comprising: carrying out solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain thallus sediment and fermentation clear liquid; and then carrying out chromatographic adsorption treatment on the fermentation clear liquid in a chromatographic column to obtain the treated fermentation clear liquid.

According to the invention, the chromatographic separation medium used in the chromatographic adsorption treatment can be various conventional chromatographic adsorption media, and for example, can be one or more of nonpolar macroporous adsorption resin, weak polar macroporous adsorption resin, strong polar macroporous adsorption resin and ion exchange resin. According to a particularly preferred embodiment of the invention, the chromatographic adsorption medium is an ion exchange resin, more preferably an anion exchange resin, e.g. a strongly basic anion exchange resin or a weakly basic anion exchange resin, e.g. LX-98, LSA-700 or LSA-700B, which are available from the new scientific and technical materials division ltd, west ann blue, dawn, further e.g. DA201A, DA201B, DA201M, 201, which are available from the water treatment engineering group ltd, Jiangsu Suqing, further e.g. D201, from the south resin ltd, university, housing.

The kind of the anion exchange resin is not particularly limited in the present invention, and may be various strongly basic anion exchange resins and/or weakly basic anion exchange resins known to those skilled in the art. The strongly basic anion exchange resin may be a strongly basic styrene-based anion exchange resin and/or a strongly basic phenylenediene-based anion exchange resin. The weak base anion exchange resin can be weak base styrene anion exchange resin and/or weak base phenylenediene anion exchange resin.

In the present invention, it is preferable that the anion exchange resin is a strongly basic anion exchange resin, for example, a strongly basic styrene-based anion exchange resin and/or a strongly basic phenylenediene-based anion exchange resin. Most preferably, the strong base anion exchange resin is D201, available from south major resins ltd, veranda city.

According to the invention, the chromatographic adsorption conditions can adopt conventional chromatographic adsorption conditions. Preferably, in order to further enhance the effect of the present invention, the temperature of the chromatographic adsorption treatment is 0 to 40 ℃, for example, 0 ℃, 5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃, more preferably 15 to 25 ℃, for example, 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃, 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃.

According to the invention, the flowing speed of the fermentation liquor in the chromatographic column can be selected in a wide range, preferably, in order to further improve the effect of the chromatographic adsorption treatment, the temperature of the chromatographic adsorption treatment is 0-40 ℃, and the flowing speed of the fermentation liquor in the chromatographic column is 1-3BV/h, such as 1BV/h, 1.5BV/h, 2BV/h, 2.5BV/h, 3BV/h, more preferably 1.5-2.5BV/h, such as 1.5BV/h, 1.6BV/h, 1.7BV/h, 1.8BV/h, 1.9BV/h, 2BV/h, 2.1BV/h, 2.2BV/h, 2.3BV/h, 2.4BV/h, 2.5 BV/h.

According to the present invention, the volume of the chromatography column may be a volume of a chromatography column conventional in the art, and preferably, the volume of the chromatography column is 5 to 100 ml.

According to the invention, the method of the invention may further comprise regenerating the column, which may be carried out using methods of column regeneration conventional in the art, which may include, for example, alkaline treatment and water washing. Specifically, the regeneration method may include: regenerating resin column with 2-4 wt% concentration sodium hydroxide solution in several times (2-5) the column volume at flow rate of 1-3BV/h and temperature of 15-25 deg.c. After the regeneration of the sodium hydroxide solution is finished, the pure water is eluted, and the pH value of the outlet solution is 6-8.

According to the present invention, the method of subjecting the fermentation broth of polyhydroxyalkanoate to solid-liquid separation can be performed according to the conventional operations in the art, however, the inventors of the present invention have found in their studies that the production cost of PHA can be further reduced when the solid-liquid separation includes a first solid-liquid separation and a second solid-liquid separation which are sequentially performed, more preferably, the first solid-liquid separation uses a disk-type centrifuge and the second solid-liquid separation uses a belt vacuum filter. It can be understood that, when the solid-liquid separation of the fermentation liquid of polyhydroxyalkanoate preferably includes the first solid-liquid separation and the second solid-liquid separation as described above, the fermentation supernatant includes a liquid phase obtained by the first solid-liquid separation and a liquid phase obtained by the second solid-liquid separation, that is, the first solid-liquid separation obtains a first fermentation supernatant and a first cell precipitate, the second solid-liquid separation separates the first cell precipitate again to obtain a second fermentation supernatant and a second cell precipitate, and then the first fermentation supernatant and the second fermentation supernatant are combined as the fermentation supernatant, and the second cell precipitate is subjected to the next treatment.

In the present invention, the conditions for solid-liquid separation of the fermentation liquid of polyhydroxyalkanoate are not particularly limited, and may be those conventionally used in the art, but the solid-liquid separation conditions are preferably such that the water content of the cell precipitate to be finally obtained is 40 to 90% by weight, more preferably 60 to 80% by weight. It is understood that when the solid-liquid separation includes only the first solid-liquid separation, the cell pellet is the first cell pellet as described above, and when the solid-liquid separation includes the first solid-liquid separation and the second solid-liquid separation, the cell pellet is the second cell pellet as described above.

According to a preferred embodiment of the present invention, the first solid-liquid separation is performed by using a disk-type centrifuge under such conditions that the water content of the first bacterial pellet obtained after the first solid-liquid separation is 70 to 85% by weight; and the second solid-liquid separation uses a belt type vacuum filter, and the separation condition ensures that the water content of the second thallus precipitate obtained after the second solid-liquid separation is 60-80 wt%.

According to the present invention, it is further preferred that the method further comprises subjecting the fermented clear liquid to a third solid-liquid separation before subjecting the fermented clear liquid to a chromatographic adsorption treatment in a chromatographic column, wherein the third solid-liquid separation is performed by plate-and-frame filtration using a plate-and-frame filter. The plate and frame filtration conditions preferably include: the pressure is 0.2-0.6MPa, and the filter cloth is 800 meshes and 1000 meshes.

In a second aspect, the invention also provides the use of the treated fermentation broth obtained by the treatment method as described above in PHA fermentation.

According to the invention, the treated fermentation broth is used as make-up water for the PHA fermentation medium.

Most of organic impurities harmful to PHA fermentation thalli are separated from the treated fermentation clear liquid obtained by the treatment method, so that the organic impurities can be reused in the preparation of a fermentation culture medium of the next batch, the auxiliary material cost can be reduced, the treatment amount of high-salinity wastewater can be reduced, and the discharge of three wastes can be reduced. In addition, the invention can also effectively ensure the fermentation efficiency of the fermentation strain, thereby ensuring the PHA yield.

According to the invention, the fermentation medium contains the treated fermentation broth obtained by the treatment method described above.

According to the present invention, urea, corn steep liquor, glucose, inorganic salts (at least one of sodium chloride, potassium chloride, sodium phosphate, sodium sulfate, potassium dihydrogen phosphate and magnesium sulfate; more preferably sodium chloride, magnesium sulfate and potassium dihydrogen phosphate) and trace elements may also be added to the fermentation medium as the case may be; preferably, the dosage of each substance is 20-80g/L of sodium chloride, 10-50g/L of glucose, 3-18g/L of corn steep liquor powder, 1.5-5g/L of urea, 0.1-1.5g/L of magnesium sulfate, 3-10g/L of potassium dihydrogen phosphate, 5-15mL/L of microelement mother liquor I and 1-5mL/L of microelement mother liquor II relative to 1L of fermentation medium. The trace elements I and II are described in patent CN 201010578858.8.

According to a particular application of the invention, a process for the fermentative preparation of PHA comprises: under the condition of fermentation and PHA production, inoculating PHA fermentation strains into the fermentation culture medium for fermentation, and carrying out solid-liquid separation on the fermentation liquid to obtain thallus precipitates; then, wall breaking is carried out on the thallus precipitate, and plate-frame filtration is carried out on the obtained wall-broken product to obtain the polyhydroxyalkanoate; wherein, the filter cloth of the plate-and-frame filtration is pre-coated with a polyhydroxy fatty acid ester layer.

According to the present invention, it is preferable that the average particle size of the polyhydroxyalkanoate pre-coated on the filter cloth is larger than the average particle size of the polyhydroxyalkanoate in the wall-broken product, which can further improve the recovery rate and purity of the obtained PHA product. In general, the particle size of the polyhydroxyalkanoate in the wall-broken product is 0.1-10 μm, preferably 0.3-5 μm. Preferably, the particle size of the polyhydroxyalkanoate pre-coated on the filter cloth is 1 to 200 μm, wherein the polyhydroxyalkanoate pre-coated on the filter cloth may be commercially available.

According to the present invention, the thickness of the polyhydroxyalkanoate layer can be selected within a wide range, and preferably, in order to further improve the purity of the resulting PHA product, the polyhydroxyalkanoate layer has a thickness of 1 to 30mm, preferably 8 to 12mm, and for example, may be 8mm, 9mm, 10mm, 11mm, or 12 mm.

According to the invention, the pore size of the filter cloth after pre-coating the polyhydroxyalkanoate layer is preferably 1-25 μm, preferably 2-10 μm, and may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm.

According to the present invention, the method of coating the polyhydroxyalkanoate layer on the filter cloth is not particularly limited, and for example, PHA may be mixed with water to prepare a suspension, and then coated on the filter cloth, and then dried to complete the coating of the polyhydroxyalkanoate layer.

According to the invention, the conditions of the plate-and-frame filtration preferably comprise: the temperature is 10-40 ℃, the pressure is 0.2-0.8MPa, and the time is 1-8 hours; more preferably: the temperature is 20-35 ℃, the pressure is 0.6-0.7MPa, and the time is 3-5 hours.

According to the present invention, the manner and conditions of the solid-liquid separation in the second aspect are not particularly limited, and the solid-liquid separation in the first aspect may be carried out as described above.

According to the present invention, it is preferable that the method of the present invention further comprises a step of washing the cell pellet before breaking the cell wall of the cell pellet. The washing can further remove impurities in the bacterial pellet, thereby further improving the purity of the PHA product. The cell pellet can be washed with a washing solution that is conventional in the art, such as water, physiological saline, and various buffers, for example, PBS buffer. The number of washing may be determined according to impurities contained in the cell pellet, and preferably, washing is performed 1 to 5 times.

According to the present invention, the method for breaking the cell wall may be a method for breaking the cell wall, which is conventional in the art, such as organic solvent extraction, physical mechanical disruption, surfactant method, enzymatic method, etc. However, the inventor of the invention finds that the organic solvent extraction method needs to add a third solvent component, and has the disadvantages of complex separation process and difficult solvent recovery; the mechanical crushing method has the problems of large energy consumption, uneven crushing, large amplification difficulty and the like; the surfactant method is somewhat toxic. Therefore, based on the above problems, the inventors of the present invention propose a cooking or enzymatic wall-breaking, more preferably a cooking wall-breaking, which not only solves the drawbacks of the existing wall-breaking methods, but also effectively improves the purity of the final PHA product.

According to the present invention, before the cell precipitation is subjected to cell wall breaking, the pH of the cell precipitation is preferably adjusted to a range suitable for the cell wall breaking agent, preferably 6 to 10, and more preferably 7 to 9.

According to the invention, the conditions for breaking the wall by the cooking method preferably comprise that the temperature is 60-200 ℃, the pressure is 0.1-0.3MPa, the stirring speed is 50-250rpm, and the time is 0.5-4 hours; more preferably, the temperature is 90 to 130 ℃ (90 ℃, 100 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃) and the pressure is 0.1 to 0.2MPa (0.1MPa, 0.12MPa, 0.14MPa, 0.16MPa, 0.18MPa, 0.2MPa), the stirring speed is 80 to 120rpm, and the time is 1 to 2.5 hours. Within the preferred range, the recovery rate and purity of the finally obtained PHA can be further improved.

According to the present invention, the enzyme used for the enzymatic wall-breaking may be a conventional enzyme that can be used for breaking the walls of the cells, and for example, may be at least one of lysozyme, protease and lipase.

According to the present invention, the method preferably further comprises a treatment of removing impurities and purifying the wall-broken product before the wall-broken product is subjected to plate-and-frame filtration. The inventor finds that after the thallus precipitation is subjected to wall breaking, the wall breaking product mainly comprises PHA, thallus cell walls and various intracellular components in various bacteria, and the PHA and the cell walls are basically insoluble in water. According to a preferred embodiment of the present invention, the wall-broken product is subjected to impurity removal by centrifugation under conditions such that the impurities such as cell walls are in the upper layer and PHA is in the lower layer. Thus, the upper layer contains not only most of insoluble impurities such as macromolecules but also all of soluble impurities, while the lower layer is mainly PHA insoluble matter. Wherein, the centrifugation is preferably performed by using a disk centrifuge.

More preferably, the method further comprises washing the PHA in the lower layer after the completion of the centrifugation. The washing is preferably water washing, and the degree of water washing is preferably 1 to 5 times until most impurities such as cell walls are separated out.

According to the invention, the method further comprises drying, e.g. spray drying, the polyhydroxyalkanoate.

According to the invention, the fermentation broth of the polyhydroxyalkanoate can be a fermentation broth of a microorganism which is conventional in the art and can be used for preparing polyhydroxyalkanoate, preferably, the microorganism is halophilic bacteria, for example, can be one of Halomonas, according to a preferred embodiment of the invention, the PHA zymogen is Halomonas (Halomonas sp.); more preferably, the PHA fermentation strain is Halomonas (Halomonas sp.) TD01 with the preservation number of CGMCC NO.4353(CN 201010578858.8).

According to the present invention, the PHA fermentation conditions may be those conventional in the art, for example, fresh seed broth is inoculated into the fermentation medium at an inoculum level of 5-20% by volume, and the fermentation system is fermented directly without sterilization. Controlling the temperature to be 33-37 ℃, controlling the initial dissolved oxygen to be more than 30%, controlling the dissolved oxygen by adjusting the rotating speed and the ventilation, controlling the rotating speed to be 400-; controlling the sugar concentration between 5 and 20g/L and the fermentation pH between 8 and 9 in the fermentation process, and fermenting for 40 to 60 hours.

In a third aspect, the present invention provides a system for processing polyhydroxyalkanoate fermentation broth, comprising:

the solid-liquid separation unit is used for carrying out solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain thallus sediment and fermentation clear liquor;

and the chromatographic adsorption unit is used for receiving the fermentation clear liquid and carrying out chromatographic adsorption treatment on the fermentation clear liquid in a chromatographic column to obtain the treated fermentation clear liquid.

Preferably, a chromatographic column is arranged in the chromatographic adsorption unit, and the chromatographic column is one or more of a non-polar macroporous adsorption resin chromatographic column, a weak-polar macroporous adsorption resin chromatographic column, a strong-polar macroporous adsorption resin chromatographic column and an ion exchange resin chromatographic column.

Preferably, the chromatographic column is an ion exchange resin chromatographic column.

Further preferably, the ion exchange resin chromatographic column is an anion exchange chromatographic column;

still further preferably, the anion exchange chromatography column is a strongly basic anion exchange chromatography column. Most preferably, D201, is available from south China resin, Inc. of Gallery.

Preferably, the solid-liquid separation unit comprises a first solid-liquid separation zone, and is used for performing first solid-liquid separation on the fermentation liquor of the polyhydroxyalkanoate to obtain a first fermentation clear liquid and a first thallus precipitate; and a second solid-liquid separation zone for carrying out second solid-liquid separation on the first thallus precipitate to obtain a second fermentation clear liquid and a second thallus precipitate.

Preferably, a disc-type centrifuge is arranged in the first solid-liquid separation zone, and a belt type vacuum filter is arranged in the second solid-liquid separation zone.

Preferably, the first solid-liquid separation unit is further provided with a third solid-liquid separation zone for performing third solid-liquid separation on the fermented clear liquid (including the first fermented clear liquid and the second fermented clear liquid) before conveying the fermented clear liquid to the chromatographic adsorption unit, wherein a plate-and-frame filter is arranged in the third solid-liquid separation zone.

Preferably, the system further comprises a chromatographic column regeneration unit, wherein the chromatographic column regeneration unit comprises an alkali treatment decolorization area and a water elution salt area and is used for carrying out alkali treatment decolorization and desalination treatment on the chromatographic column so as to regenerate the chromatographic column.

Preferably, the system also comprises a polyhydroxyalkanoate fermentation unit which is connected with the adsorption unit or the second solid-liquid separation unit and used for fermenting polyhydroxyalkanoate by using the treated fermentation clear liquid or the salt-containing fermentation waste liquid. Wherein the fermentation clear liquid or the salt-containing fermentation waste liquid is used as at least part of liquid preparation water of the polyhydroxyalkanoate fermentation culture medium.

Preferably, the system further comprises a polyhydroxyalkanoate extraction unit, wherein the polyhydroxyalkanoate extraction unit comprises a thallus crushing area and a PHA separation area.

Wherein a plate and frame filter is arranged in the PHA separation area, and a polyhydroxy fatty acid ester layer is pre-coated on filter cloth in the plate and frame filter.

Preferably, the thickness of the polyhydroxyalkanoate layer is 1 to 30 mm.

Preferably, the pore size of the filter cloth after pre-coating the polyhydroxyalkanoate layer is preferably 1 to 25 μm, preferably 2 to 10 μm.

Preferably, the PHA separation zone is also provided with an impurity removal zone so as to carry out pre-impurity removal on the wall-broken product. The impurity removing area is preferably provided with a disc type centrifugal separator.

Preferably, the cell disruption area is further provided with a cell-disruption agent supply device and/or a pressure heating device, so that the cell is subjected to cell disruption in the presence of a cell-disruption agent or a high temperature and high pressure.

The polyhydroxyalkanoate extraction unit further comprises a water washing area arranged on the upstream of the thallus crushing area, so that water washing and impurity removal are carried out before the thallus precipitate is crushed.

Preferably, the polyhydroxyalkanoate extraction unit further comprises a drying zone to dry the separated polyhydroxyalkanoate. The drying zone may be provided with a spray dryer.

Preferably, the system also comprises a PHA fermentation unit, and is connected with the chromatographic adsorption unit, and is used for receiving fermentation liquor treated by the chromatographic adsorption unit for the preparation of PHA fermentation medium.

The present invention will be described in detail below by way of examples. In the following examples:

the disk centrifuge is purchased from Nanjing Huasheng separation mechanical technology Limited, model DR 203;

the belt type vacuum filter is purchased from Huzhou nuclear energy-saving environment-friendly filtration technology Limited company, and has the model number DY-500;

the plate-and-frame filter is purchased from Hainin Yunfei filtration equipment Co., Ltd, model YF-100-1;

ion exchange resins of model LSA-700 and LSA-700B were purchased from New scientific and technological materials, Inc. in the West Anlan at late dawn;

the ion exchange resins with the model number of DA201B are purchased from Jiangsu Suqing water treatment engineering group, Inc.;

the ion exchange resin with the model D201 is purchased from south big resin Co., Tokuwa city;

the polyhydroxyalkanoate is purchased from blue crystal biotechnology limited, has a particle size of 1-50 μm, and is used for coating on the filter cloth of a plate-and-frame filter to form a polyhydroxyalkanoate layer;

reference to methods for detecting PHA recovery and purity (Engineering self-flocculation of Halomonas camphaniensis for wastepa procedure open and concentration);

OD of Halomonas biomass in fermentation broth₆₀₀The values are represented.

Fermentation strain

Halomonas sp TD01 with preservation number of CGMCC NO.4353(CN 201010578858.8).

Seed culture medium

5g/L of yeast powder, 10g/L of peptone and 60g/L of sodium chloride.

Initial fermentation medium

50g/L of sodium chloride, 50g/L of glucose, 15g/L of corn starch, 2g/L of urea, 0.2g/L of magnesium sulfate, 5g/L of monopotassium phosphate, 10mL/L of microelement mother liquor and 3mL/L of microelement mother liquor II. The microelement mother liquids I and II refer to the cited patent CN 201010578858.8.

Supplementary culture medium

The concentration of glucose is 600g/L, and the concentration of corn starch is 40 g/L.

Preparation of fermentation broth

This preparation example is illustrative of the preparation of a polyhydroxyalkanoate fermentation broth

Inoculating Halomonas into seed culture medium, performing primary activation culture at 37 deg.C and 200rpm, and culturing to OD₆₀₀Reaching about 4 to obtain first-grade seed liquid;

inoculating the primary seed solution into a seed culture medium with an inoculation amount of 10 vol%, performing secondary activation culture at 37 deg.C and 200rpm, and culturing to OD₆₀₀And obtaining a secondary seed liquid when the yield reaches about 4, and obtaining a fermented seed liquid.

Then inoculating the second-level seed liquid into the initial fermentation medium by the inoculation amount of 10 volume percent, and directly fermenting the fermentation system without sterilization. Controlling the temperature at 37 ℃, the rotating speed at 600-; during the fermentation process, the sugar concentration is controlled to be between 5 and 20g/L by feeding, the fermentation pH is controlled to be between 8 and 9 by NaOH, and the fermentation is carried out for 48 hours.