Method and device for separating artificially synthesized starch reaction liquid

Abstract

The invention relates to a separation method of an artificially synthesized starch reaction liquid, which comprises the following steps: (1) separating and filtering the artificially synthesized starch reaction liquid through at least one stage of membrane, intercepting artificially synthesized starch, permeating other components in the reaction liquid, and stirring at the interception side in the membrane separation and filtering to respectively obtain a concentrated liquid and a permeate liquid; and (2) carrying out post-treatment on the concentrated solution to obtain the artificially synthesized starch, and carrying out post-treatment on the permeate to obtain an enzyme concentrated solution. The concentration of the artificially synthesized starch is realized through membrane separation, new impurities are not introduced, small molecular impurities such as enzyme, monosaccharide and salt are removed, and the effective purification of the starch is realized. Meanwhile, the separation process is mild, the activity of the enzyme is not damaged, and recovery and cyclic utilization of the enzyme are facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of artificial synthetic starch separation, and particularly relates to a separation method and device for artificial synthetic starch reaction liquid. BACKGROUND

[0002] Starch is the main source of energy for human beings and is also an important industrial raw material. Chinese scientists have realized the de novo synthesis of carbon dioxide into starch, which makes the traditional starch production mode based on agricultural planting expected to be transformed into an industrial workshop production mode.

[0003] The synthesis of starch from a six-carbon sugar under the catalysis of various enzyme catalysts is the last step in the reaction path from carbon dioxide to artificial starch, and the artificial synthetic starch reaction system for the enzyme-catalyzed synthesis of starch from a six-carbon sugar is a liquid phase system, which is referred to as artificial synthetic starch reaction liquid hereinafter. At present, the concentration of starch in the artificial synthetic starch reaction liquid is generally less than 2 g / L, which is difficult to directly purify or dry to prepare starch products.

[0004] Natural starch is derived from plants, and generally uses grains, fruits, roots, or tubers, etc. of plants as raw materials. In the production process of natural starch, the removal of bran and other large-particle impurities from the slurry obtained by crushing and grinding plants involves the separation of impurities and the purification and separation of starch and protein. The removal of bran and other large-particle impurities from the slurry generally adopts screen filtration, which retains the bran and other millimeter-level impurities, and allows the starch to pass through the liquid. For example, CN120204810A discloses a starch slurry dewatering system, and the separation of starch and protein generally uses centrifugation or hydrocyclone separation, in which the protein is condensed to form gluten, and the separation of starch and gluten is realized, and then the starch and gluten products are obtained by drying. For example, Yuan Chao et al. in the study of wheat starch separation method (Grain Processing, 2005, 48-50) centrifuged the concentrated wheat slurry at 3300 r / min for 8 min, and the upper layer of the precipitate in the centrifuge tube was gluten, the middle layer was gluten mixed with starch, and the lower layer was relatively pure starch. CN120324994A discloses a wheat protein and starch separation device, which comprises a centrifugal auxiliary rotating mechanism and a plurality of groups of slurry filter pressing mechanisms arranged on the centrifugal auxiliary rotating mechanism. In the device, the slurry is subjected to centrifugal motion in the process of continuous pressurization, which is equivalent to combining filter pressing with centrifugation, and cannot avoid the condensation of protein.

[0005] The inventors found that the artificial starch reaction solution is composed of micron artificial starch, macromolecular enzyme catalyst, small molecule salt and water, which is different from the plant broken and ground slurry solution and does not contain millimeter particles. The method for separating and removing the bran and other impurities from the plant broken and ground slurry solution by intercepting the millimeter particles is not applicable to the separation and concentration of the micron starch in the artificial starch reaction solution. On the other hand, the activity of the enzyme is the prerequisite for realizing the recycling of the enzyme catalyst, and the method for separating and removing the natural starch from the protein by utilizing the denaturation of the protein is difficult to ensure the activity of the enzyme and is not applicable to the separation and concentration of the starch from the artificial starch reaction solution.

[0006] In summary, the sieve filtration method in the prior art cannot meet the separation requirement of the micron starch, and the centrifugal liquid separation method may damage the activity of the enzyme catalyst and cause the enzyme catalyst to be unable to be recycled. Therefore, how to realize the separation and concentration of the artificial starch in the artificial starch reaction solution and retain the activity of the macromolecular enzyme catalyst to ensure the recycling of the enzyme catalyst has become a problem to be solved at present. SUMMARY

[0007] To solve the above technical problems, the artificial starch in the artificial starch reaction solution is intercepted by the membrane separation, and the water, enzyme and small molecules and other impurities are allowed to pass through, so as to realize the separation and concentration of the artificial starch in the artificial starch reaction solution and support the large-scale production of the artificial starch.

[0008] To achieve the above purpose, the technical scheme of the present application is as follows:

[0009] In a first aspect, the present application provides a separation method of an artificial starch reaction solution, which comprises:

[0010] (1) filtering the artificial starch reaction solution through at least one membrane separation, the artificial starch is intercepted, and the remaining components in the reaction solution pass through, the membrane separation is stirred on the interception side, and a concentrated solution and a permeate are obtained respectively;

[0011] (2) the concentrated solution is treated to obtain the artificial starch, and the permeate is treated to obtain an enzyme concentrate.

[0012] The present application realizes the concentration of the artificial starch by the membrane separation, can not introduce new impurities, removes the small molecule impurities such as monosaccharide and salt, realizes the concentration and purification of the starch, and the separation process is mild and does not damage the activity of the enzyme catalyst, which is helpful to the recovery and recycling of the enzyme.

[0013] The following is a preferred technical scheme of the present application, but is not a limitation on the technical scheme provided by the present application. The following preferred technical scheme can better achieve and realize the purpose and beneficial effects of the present application.

[0014] The separation method of the present application is suitable for artificial synthetic starch reaction liquid with low starch concentration and small particle size, solves the problem of difficult direct purification and drying of low-concentration starch, supports the purification and drying of artificial synthetic starch, and realizes the large-scale production of artificial synthetic starch products.

[0015] As a preferred technical solution of the present application, the separation method further comprises freezing the artificial starch reaction liquid, thawing, and then performing membrane separation filtration.

[0016] Preferably, the freezing temperature is -80~-10℃, for example, it can be -80℃, -60℃, -40℃, -20℃, -15℃ or -10℃, etc.

[0017] Preferably, the freezing time is ≥4h, for example, it can be 4h, 6h, 8h, 10h, 12h or 15h, etc.

[0018] The present application can further promote the separation of starch and its combined enzyme, reduce the residual enzyme content in the concentrated liquid, and improve the recycling rate of the enzyme by freezing the artificial starch reaction liquid, thawing, and then performing membrane separation filtration.

[0019] Preferably, the pH value of the artificial synthetic starch reaction liquid is adjusted to 8~10 before membrane separation filtration, for example, it can be 8, 8.5, 9, 9.5, 9.8 or 10, etc.

[0020] Preferably, the pH value adjusting agent comprises a sodium carbonate solution.

[0021] Preferably, the concentration of the sodium carbonate solution is 100g / L.

[0022] The present application can further improve the membrane separation efficiency and ensure the enzyme activity by adjusting the pH of the reaction liquid.

[0023] As a preferred technical solution of the present application, the membrane separation filtration is cross-flow filtration, and the retentate liquid flows from top to bottom.

[0024] Preferably, the membrane separation filtration is stirred on the retentate side.

[0025] The present application reduces the membrane flux decline caused by filter cake accumulation on the membrane surface by stirring, and improves the filtration rate.

[0026] Preferably, the membrane pore size of the membrane separation filtration is 0.1~50μm, for example, it can be 0.1μm, 5μm, 20μm, 35μm, 45μm or 50μm, etc.

[0027] Preferably, when the membrane separation filtration is multi-stage membrane separation filtration, the membrane pore size gradually decreases at each stage.

[0028] The application improves the filtering efficiency by step-by-step filtering, avoids excessive pressure drop caused by single small aperture filtering, and reduces the filtering rate.

[0029] Preferably, the pressure difference of the membrane separation filtering is 0.1-0.15 MPa, for example, it can be 0.1 MPa, 0.11 MPa, 0.12 MPa, 0.14 MPa, 0.145 MPa or 0.15 MPa, etc.

[0030] Preferably, the temperature of the membrane separation filtering is 20-35 ℃, for example, it can be 20 ℃, 25 ℃, 28 ℃, 32 ℃, 34 ℃ or 35 ℃, etc.

[0031] As a preferred technical solution of the application, when the filtering flux decreases by 20-40%, the membrane separation filtering is performed by forward flushing and / or back flushing.

[0032] Preferably, the flushing liquid of the flushing includes any one or a combination of at least two of tap water, deionized water, sodium hydroxide solution or sodium carbonate solution.

[0033] Preferably, the pH of the sodium hydroxide solution or the sodium carbonate solution is 10-11, for example, it can be 10, 10.2, 10.5, 10.8, 10.9 or 11, etc.

[0034] The application effectively removes the micron-sized starch residues, macromolecular enzyme catalyst agglomerates and small-molecule salt deposits attached to the membrane surface by flushing. When a neutral flushing liquid such as tap water or deionized water is used, the loose pollutants on the membrane surface can be stripped under mild conditions, avoiding damage to the membrane structure and enzyme activity. When sodium hydroxide solution or sodium carbonate solution is selected, part of the stubborn deposited salt in the membrane pores can be dissolved, and at the same time, slight hydrolysis of the residual starch occurs. The activity of the enzyme catalyst is not damaged during the flushing process, further dredging the membrane pore channel, reducing the irreversible damage of the membrane module caused by long-term blockage, and prolonging the service life of the membrane.

[0035] Preferably, the post-treatment of the concentrated solution includes washing, dewatering and drying performed in sequence.

[0036] Preferably, the washing is performed synchronously with the membrane separation filtering or after the membrane separation filtering.

[0037] Preferably, the washing includes adding a washing liquid, stirring, and then performing membrane separation filtering until the washing through liquid volume is greater than or equal to the washing liquid volume, to complete one washing.

[0038] Preferably, the washing is repeated for 1-3 times, for example, it can be 1 time, 2 times or 3 times, etc.

[0039] Preferably, the stirring is performed for 5-10 minutes, for example, 5 minutes, 6 minutes, 7.5 minutes, 9 minutes, 9.5 minutes, or 10 minutes, etc.

[0040] Preferably, the washing liquid of the washing comprises one or a combination of at least two of deionized water, an aqueous EDTA solution, an aqueous urea solution, an aqueous SDS solution, or an aqueous sodium hydroxide solution, etc.

[0041] Preferably, the volume of the washing liquid is 0.25-1.5 times the volume of the artificial synthetic starch reaction liquid, for example, 0.25 times, 0.5 times, 1 times, 1.2 times, 1.4 times, or 1.5 times, etc.

[0042] As a preferred technical solution of the present application, the permeate and the washing liquid are separated by ultrafiltration to separate enzymes and small molecular impurities in the permeate, obtaining an enzyme concentrate.

[0043] Preferably, the filter membrane for ultrafiltration separation has a molecular weight cut-off range of 20-50 kDa, for example, 20 kDa, 25 kDa, 30 kDa, 40 kDa, 45 kDa, or 50 kDa, etc.

[0044] The dehydration described in the present application can use the commonly used dehydration method in the art, for example, centrifugation, hydrocyclone separation, or filter pressing, etc., which are not further limited herein.

[0045] The drying described in the present application can use the commonly used drying method in the art, for example, fluidized bed drying, which is not further limited herein.

[0046] In a second aspect, the present application provides a separation device for the separation method described in the first aspect, the separation device comprising at least one microfiltration device and an ultrafiltration device, the feed inlet of the microfiltration device being injected with the artificial synthetic starch reaction liquid, the outlet of the microfiltration device obtaining the concentrate and the permeate, respectively, the permeate being injected into the ultrafiltration device to obtain the enzyme concentrate, and the microfiltration device comprising an external pressure membrane separation concentration device or an internal pressure membrane separation concentration device.

[0047] As a preferred technical solution of the present application, when the microfiltration device is a multi-stage microfiltration device, the microfiltration devices are connected in series, and the permeate of the upper stage microfiltration device is injected into the feed inlet of the lower stage microfiltration device.

[0048] As a preferred technical solution of the present application, the internal pressure membrane separation concentration device and the internal pressure membrane separation concentration device both comprise a stirring device, and the stirring device is arranged on the cut-off side.

[0049] Preferably, the inner pressure type membrane separation concentration device comprises a shell, a membrane assembly and a stirring device, the membrane assembly and the shell are sealingly connected to form a permeate cavity inside the membrane assembly and a concentrated liquid cavity outside the membrane assembly, the permeate cavity is provided with a permeate outlet, a backwash liquid inlet and a vacuum suction port, the permeate outlet can serve as a backwash liquid outlet, the shell of the concentrated liquid cavity is provided with an artificial synthetic starch reaction liquid inlet, a pressurizing port and a concentrated liquid outlet, the artificial synthetic starch reaction liquid inlet can serve as a forward flushing liquid inlet, the concentrated liquid outlet can serve as a forward flushing liquid outlet, the concentrated liquid cavity is internally provided with a pressure sensor, and the stirring device comprises a stirring paddle and a motor.

[0050] Preferably, the outer pressure type membrane separation concentration device comprises a shell, a membrane assembly and a stirring device, the membrane assembly and the shell are sealingly connected to form a concentrated liquid cavity inside the membrane assembly and a permeate cavity outside the membrane assembly, the permeate cavity is provided with a permeate outlet, a backwash liquid inlet and a vacuum suction port, the permeate outlet can serve as a backwash liquid outlet, the shell of the concentrated liquid cavity is provided with an artificial synthetic starch reaction liquid inlet, a pressurizing port and a concentrated liquid outlet, the artificial synthetic starch reaction liquid inlet can serve as a forward flushing liquid inlet, the concentrated liquid outlet can serve as a forward flushing liquid outlet, the concentrated liquid cavity is internally provided with a pressure sensor, and the stirring device comprises a stirring paddle and a motor.

[0051] Preferably, the distance between the tip of the stirring paddle of the stirring device and the membrane surface is not greater than 1.5 cm, for example, it can be 0.2 cm, 0.4 cm, 0.6 cm, 0.8 cm, 1 cm or 1.5 cm, etc.

[0052] Preferably, the stirring paddle blade comprises a blade with a cross-sectional area near the membrane surface smaller than that near the stirring shaft.

[0053] Preferably, the stirring paddle blade further comprises a wavy blade, and the wavy blade is arranged parallel to the membrane surface.

[0054] In the present application, when the distance between the tip of the stirring paddle and the membrane surface is not greater than 1.5 cm, the starch particles gathered near the membrane surface can settle in time without being closely combined with the membrane. Further, through the special shape design of the stirring paddle, small eddies are formed between the tip of the paddle and the membrane surface, so that the starch gathers and settles near the membrane surface without being attached to the membrane, so that the filtration flux remains basically stable.

[0055] The stirring paddle blade in the present application can be made of stainless steel, enamel, polytetrafluoroethylene, nylon or silicone, etc., and is preferably made of polytetrafluoroethylene, nylon or silicone, etc. which have certain elasticity and soft texture.

[0056] Preferably, the membrane assembly in the microfiltration device comprises any one of a roll-type membrane, a hollow fiber type membrane or a tubular membrane, and is preferably a hollow fiber type membrane and a tubular membrane.

[0057] Preferably, the filter membrane material of the membrane assembly comprises any one of stainless steel filter membrane, ceramic filter membrane or organic filter membrane.

[0058] Preferably, the membrane with a pore size of ≥5 μm adopts stainless steel filter membrane or ceramic membrane, and the filter membrane with a pore size of <5 μm adopts any one of PVDF, PES, PS or MCE.

[0059] Compared with the prior art, the present application has at least the following beneficial effects:

[0060] (1) The separation method provided by the present application can be applied to the separation of artificial synthetic starch reaction liquid, can realize the concentration and separation of low-concentration small-particle-size starch, the concentration multiple can reach 2-20, the concentration yield of starch can reach 70-92%, no new impurities are introduced, the enzyme in the reaction liquid can be recovered, the activity of the enzyme is not damaged, and the circulation of the enzyme is facilitated;

[0061] (2) The separation device provided by the present application can realize efficient separation, realize gradient fractional concentration of starch particles, reduce energy consumption, improve separation efficiency, and dynamically filter to improve the stability of membrane flux in the use process of membrane separation. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 is a separation method flow chart of the artificial synthetic starch reaction liquid provided by embodiment 1 of the present application;

[0063] Figure 2 is a structure diagram of an external pressure type membrane separation and concentration device adopted in some embodiments of the present application;

[0064] Figure 3 is a structure diagram of an internal pressure type membrane separation and concentration device adopted in some embodiments of the present application;

[0065] Figure 4 is a structure diagram of an internal pressure type membrane separation and concentration device adopted in comparative example 1 of the present application;

[0066] In the figure, 1 is a membrane separation and concentration device shell, 2 is a membrane assembly, 3 is a stirring paddle, 4 is a motor, 5 is a feed liquid / positive washing liquid inlet, 6 is a concentrated liquid / positive washing liquid outlet, 7 is a permeate liquid / backwashing liquid outlet, 8 is a backwashing liquid inlet, 9 is a pressurizing port, 10 is a vacuumizing port, 11 is a pressure sensor. DETAILED DESCRIPTION

[0067] In order to facilitate the understanding of the present application, the present application lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0068] Example 1

[0069] This embodiment provides a method for separating a reaction solution of artificially synthesized starch, such as... Figure 1 As shown, the separation method includes:

[0070] (1) Freeze 25L of synthetic starch reaction solution at -20℃ for about 24 hours, thaw and adjust the pH to 9, then pour it into the feed tank. Connect the feed tank's outlet pipe to the feed tank using a primary pump. Figure 2 The feed inlet pipe of the external pressure membrane separation and concentration device (stage 1) shown is connected to the reaction solution. The starch concentration in the reaction solution is 1.53 g / L, the BSA equivalent concentration of the enzyme is approximately 0.88 g / L, the glucose equivalent concentration of the monosaccharide is approximately 0.81 g / L, and the phosphate concentration is approximately 0.04 mol / L. The membrane separation and concentration device is divided into four stages. The membrane module of the stage 1 is a stainless steel membrane tube (total membrane area 0.1 m²). 2 (50 μm pore size), the secondary unit membrane module is a stainless steel membrane tube (total membrane area 0.2 m²). 2 (10 μm pore size), the third-stage membrane module is a PVDF membrane tube (total membrane area 0.4 m²). 2 (1 μm pore size), the fourth-stage membrane module is a PVDF membrane tube (total membrane area 0.6 m²). 2 (0.1 μm pore size) The membrane tubes at each stage are uniformly distributed radially and circumferentially; the secondary pump connects the permeate outlet of the primary unit to the feed inlet of the secondary unit, the tertiary pump connects the permeate outlet of the secondary unit to the feed inlet of the tertiary unit, and the quaternary pump connects the permeate outlet of the tertiary unit to the feed inlet of the quaternary unit. Each stage of the unit is equipped with... Figure 2The stirring paddle is shown; the pressure of each stage of the separation and concentration device is set to 0.1 MPa, the stirring is started, the filtration is performed at a temperature of 25°C, after 3 hours of filtration, the stirring is stopped, the pump is turned off, the pressure is released, and the microfiltration is stopped; the concentrated liquid of each stage is added to deionized water, after 10 minutes of stirring, the washing is started, when the volume of the permeate is not less than the volume of the washing liquid, the stirring is stopped, the pump is turned off, the washing is stopped, and the operation is repeated 3 times; the concentrated liquid of each stage is obtained: the volume of the first stage concentrated liquid is about 0.25 L, the starch concentration is 15.1 g / L, the starch concentration multiple is 9.87, the concentration yield is 9.87%, and the product yield is 9.15%; the volume of the second stage concentrated liquid is 0.67 L, the starch concentration is 17.79 g / L, the starch concentration multiple is 11.63, the concentration yield is 31.16%, and the product yield is 28.67%; the volume of the third stage concentrated liquid is 0.77 L, the starch concentration is 19.47 g / L, the starch concentration multiple is 12.73, the concentration yield is 39.19%, and the product yield is 35.77%; the volume of the fourth stage concentrated liquid is 0.83 L, the starch concentration is 7.65 g / L, the starch concentration multiple is 4.61, the concentration yield is 16.60%, and the product yield is 14.96%; the total starch concentration yield is about 96.82%, and the total starch product yield is about 88.55%; the volume of the permeate of the fourth stage device is about 22.50 L, the BSA equivalent concentration of the enzyme in the permeate is about 0.72 g / L, and the recovery rate of the enzyme is about 73.63%;

[0071] (2) The concentrated liquid of each stage is centrifuged and dried to obtain the starch product, the total mass of the starch product is 33.87 g, the starch product yield is 88.55%, the permeate is subjected to ultrafiltration to obtain an enzyme concentrated liquid, the ultrafiltration filter membrane is a PVDF ultrafiltration membrane with a molecular weight of 30 kDA, and the BSA equivalent concentration of the enzyme in the enzyme concentrated liquid is 2.95 g / L.

[0072] Example 2

[0073] The present embodiment provides a separation method for an artificial synthetic starch reaction liquid, the separation method comprising:

[0074] The 10 L artificial synthetic starch reaction liquid is frozen at -20°C for about 24 hours, and after thawing and adjusting the pH to 9, it is poured into a feed liquid tank, connected to an external pressure type membrane separation and concentration device through a feed liquid inlet pipe, and pumped into the external pressure type membrane separation and concentration device through a feed liquid inlet pipe Figure 2 The starch concentration in the reaction liquid is 1.53 g / L, the BSA equivalent concentration of the enzyme is about 0.88 g / L, the glucose equivalent concentration of monosaccharide is about 0.81 g / L, and the phosphate concentration is about 0.04 mol / L, the membrane assembly of the external pressure type membrane separation and concentration device is a PVDF membrane tube, the total membrane area is 0.3 m 2 , the pore size is 0.22 μm, the membrane tube is uniformly distributed along the circumference, and the stirring paddle is Figure 2The stirring paddle is shown, the pressure of the separation and concentration device is set to 0.1 MPa, the stirring is started, the filtration is carried out at a temperature of 25℃, every time the filtration flux decreases by 30%, backwash for 5 min, after filtration for 4 h, stop stirring, close the pump, depressurize, stop microfiltration; the membrane separation and concentration liquid is added to the washing material liquid tank, the stirring is started and the washing liquid is added, after stirring for 5 min, the pump of the washing membrane separation device is started, when the volume of the permeate is not less than the volume of the washing liquid, stop stirring, close the pump, stop washing, repeat the operation for 3 times; the volume of the concentrated liquid is 0.72 L, the starch concentration in the concentrated liquid is 19.76 g / L, the glucose equivalent concentration of monosaccharide is about 0.1 g / L, the phosphate concentration is about 0.03 mol / L, the starch concentration multiple is 12.92, the starch concentration yield is 92.99%, the monosaccharide removal rate is about 99.11%, and the phosphate removal rate is 94.60%; the volume of the permeate is 9.18 L, the BSA equivalent concentration of the enzyme in the permeate is 0.65 g / L, and the recovery rate of the enzyme is 67.80%;

[0075] (2) The washed starch slurry is centrifuged to remove water, and the starch product is obtained by drying at 60℃, the mass of the starch product is 12.76 g, and the yield of the starch product is about 83.39%, the permeate is subjected to ultrafiltration to obtain an enzyme concentrate, the ultrafiltration filter membrane is a PVDF ultrafiltration membrane with a molecular weight of 30kDA, and the BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.54 g / L.

[0076] Example 3

[0077] The present embodiment provides a separation method for an artificial synthetic starch reaction liquid, the separation method comprising:

[0078] (1) 10 L of artificial synthetic starch reaction liquid is adjusted to a pH of 9 and poured into a material liquid tank, and connected to the material liquid inlet pipe of an external pressure type membrane separation and concentration device through a delivery pump Figure 2 The starch concentration in the reaction liquid is 1.95 g / L, the BSA equivalent concentration of the enzyme is 0.82 g / L, and the glucose equivalent concentration of monosaccharide is 0.77 g / L, the membrane assembly of the external pressure type membrane separation and concentration device is 6 PVDF membrane tubes, the total membrane area is 0.3 m 2, the membrane tubes are uniformly distributed along the radial and circumferential directions, the stirring paddle is a wave-shaped stirring paddle, the pressure of the separation and concentration device is set to 0.1 MPa, the stirring is started, the filtration is carried out at a temperature of 25°C, after 3 hours of filtration, the stirring is stopped, the pump is turned off, the pressure is released, and the microfiltration is stopped, a concentrated liquid with a volume of 2.37 L is obtained, the starch concentration in the concentrated liquid is 6.68 g / L, the starch concentration multiple is 3.43, and the starch yield is 81.19%; the glucose equivalent concentration of monosaccharide in the concentrated liquid is 0.11 g / L, the monosaccharide removal rate is 96.84%, the volume of the permeate is 7.53 L, the BSA equivalent concentration of the enzyme in the permeate is 0.46 g / L, and the enzyme recovery rate is 42.24%;

[0079] (2) The concentrated liquid is subjected to centrifugation and drying to obtain a starch product, the mass of the starch product is 13.93 g, and the starch product yield is 71.44%; the permeate is subjected to ultrafiltration to obtain an enzyme concentrate, the ultrafiltration membrane is a PVDF ultrafiltration membrane with a molecular weight cut-off of 30 kDA, and the BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.12 g / L.

[0080] Example 4

[0081] The present embodiment provides a separation method for an artificial synthetic starch reaction liquid, and the separation method comprises the following steps:

[0082] (1) 10 L of artificial synthetic starch reaction liquid is adjusted to a pH of 9 and then poured into a feed liquid tank, and then connected to a feed liquid inlet 5 of an external pressure type membrane separation and concentration device as shown in Figure 2 , the starch concentration in the reaction liquid is 1.95 g / L, the BSA equivalent concentration of the enzyme is 0.82 g / L, and the glucose equivalent concentration of monosaccharide is 0.77 g / L, the membrane assembly 2 of the external pressure type membrane separation and concentration device is 6 PVDF membrane tubes, the total membrane area is 0.3 m 2 , the pore size is 0.22 μm, the membrane tubes are uniformly distributed along the radial and circumferential directions, the stirring paddle 3 is a wave-shaped stirring paddle, the minimum distance between the stirring paddle and the membrane surface is less than 1 cm, the pressure of the separation and concentration device is set to 0.1 MPa, the stirring is started, the filtration is carried out at a temperature of 25°C, after 3 hours of filtration, the stirring is stopped, the pump is turned off, the pressure is released, and the microfiltration is stopped, a concentrated liquid with a volume of 3.21 L is obtained, the starch concentration in the concentrated liquid is 4.56 g / L, the starch concentration multiple is 2.34, and the starch yield is 75.06%; the glucose equivalent concentration of monosaccharide in the concentrated liquid is 0.09 g / L, the monosaccharide removal rate is 96.24%, the volume of the permeate is 6.69 L, the BSA equivalent concentration of the enzyme in the permeate is 0.48 g / L, and the enzyme recovery rate is 39.16%;

[0083] (2) The concentrated liquid is centrifuged and dried to obtain starch product with a starch product mass of 13.31g and a starch product yield of 68.26%. The permeate is ultrafiltered to obtain enzyme concentrate with a 30kDA PVDF ultrafiltration membrane and the enzyme BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.16g / L.

[0084] Example 5

[0085] This embodiment provides a method for separating a synthetic starch reaction solution, the separation method comprising:

[0086] (1) After adjusting the pH of 10L of synthetic starch reaction solution to 9, pour it into the feed tank and then transfer it to the feed tank via a transfer pump. Figure 2 The feed inlet pipe of the external pressure membrane separation and concentration device shown is connected. The starch concentration in the reaction solution is 1.95 g / L, the BSA equivalent concentration of the enzyme is 0.82 g / L, and the glucose equivalent concentration of the monosaccharide is 0.77 g / L. The membrane module of the external pressure membrane separation and concentration device is a PVDF membrane tube with a total membrane area of ​​0.3 m². 2 The pore size is 0.22 μm, the membrane tubes are uniformly distributed radially and circumferentially, and the stirring impeller is... Figure 2 The stirring paddle shown was used. The pressure of the separation and concentration device was set to 0.1 MPa. Stirring was started, and filtration was performed at 25°C. After filtration for 3 hours, stirring was stopped, the pump was turned off, the pressure was released, and microfiltration was stopped. The volume of the concentrated liquid obtained was 2.23 L, the starch concentration in the concentrated liquid was 7.31 g / L, the starch concentration factor was approximately 3.75, and the starch recovery rate was 83.65%. The glucose equivalent concentration of monosaccharides in the concentrated liquid was 0.08 g / L, the monosaccharide removal rate was 97.68%, the permeate volume was 7.67 L, the BSA equivalent concentration of enzymes in the permeate was 0.49 g / L, and the enzyme recovery rate was 45.83%.

[0087] (2) The concentrated liquid is centrifuged and dried to obtain starch product with a mass of 14.69 g and a starch product yield of 75.33%. The permeate is ultrafiltered to obtain enzyme concentrate with a 30 kDa PVDF ultrafiltration membrane and the enzyme BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.11 g / L.

[0088] Example 6

[0089] This embodiment provides a method for separating a synthetic starch reaction solution, the separation method comprising:

[0090] (1) After adjusting the pH of 10L of synthetic starch reaction solution to 9, pour it into the feed tank and then transfer it to the feed pump. Figure 2The starch concentration in the reaction solution is 1.95 g / L, the BSA equivalent concentration of the enzyme is 0.82 g / L, and the glucose equivalent concentration of the monosaccharide is 0.77 g / L. The membrane assembly of the external pressure type membrane separation and concentration device is a PVDF membrane tube, the total membrane area is 0.3 m 2 , the pore size is 0.22 μm, the membrane tube is uniformly distributed along the radial and circumferential directions, the stirring paddle is Figure 2 , the pressure of the separation and concentration device is set to 0.1 MPa, the stirring is started, the filtration is carried out at a temperature of 25℃, after 3h of filtration, the stirring is stopped, the pump is turned off, the pressure is released, and the microfiltration is stopped. The concentrated liquid volume is 2.17 L, the starch concentration in the concentrated liquid is 7.71 g / L, the starch concentration multiple is about 3.95, and the starch yield is about 85.80%; the glucose equivalent concentration of the monosaccharide in the concentrated liquid is about 0.07 g / L, the monosaccharide removal rate is about 98.03%, the permeate volume is about 7.73 L, the BSA equivalent concentration of the enzyme in the permeate is about 0.54 g / L, and the enzyme recovery rate is about 50.90%;

[0091] (2) The concentrated liquid is centrifuged and dried to obtain a starch product, the mass of the starch product is 14.87g, and the starch product yield is 76.26%. The permeate is subjected to ultrafiltration to obtain an enzyme concentrate, the ultrafiltration filter membrane is a 30kDA PVDF ultrafiltration membrane, and the BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.16g / L.

[0092] Example 7

[0093] The present embodiment provides a separation method for an artificial synthetic starch reaction solution, which comprises:

[0094] (1) After adjusting the pH of 10L artificial synthetic starch reaction solution to 9, pour it into the feed liquid tank, connect it to the feed liquid inlet pipe of the external pressure type membrane separation and concentration device shown in Figure 2 , the starch concentration in the reaction solution is 1.95 g / L, the BSA equivalent concentration of the enzyme is 0.82 g / L, and the glucose equivalent concentration of the monosaccharide is about 0.77 g / L. The membrane assembly of the external pressure type membrane separation and concentration device is a PVDF membrane tube, the total membrane area is 0.3 m 2 , the pore size is 0.22 μm, the membrane tube is uniformly distributed along the radial and circumferential directions, the stirring paddle is Figure 2The stirring paddle shown in the figure, the pressure of the separation and concentration device is set to 0.1 MPa, the stirring is started, the filtration is carried out at a temperature of 25℃, after 4h of filtration, the stirring is stopped, the pump is turned off, the pressure is released, the microfiltration is stopped, the concentrated liquid volume is 1.31 L, the starch concentration in the concentrated liquid is 13.47 g / L, the starch concentration multiple is about 6.91, and the starch yield is about 90.49%; the glucose equivalent concentration of monosaccharide in the concentrated liquid is about 0.05 g / L, the monosaccharide removal rate is about 99.15%, the permeate volume is about 8.59 L, the BSA equivalent concentration of the enzyme in the permeate is about 0.53 g / L, and the enzyme recovery rate is about 49.48%;

[0095] (2) The concentrated liquid is subjected to centrifugation and drying to obtain a starch product, the mass of the starch product is 16.06 g, and the starch product yield is 82.35%; the permeate is subjected to ultrafiltration to obtain an enzyme concentrate, the ultrafiltration filter membrane is a PVDF ultrafiltration membrane with a molecular weight of 30 kDA, and the BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.09 g / L.

[0096] Example 8

[0097] The present embodiment provides a separation method of an artificial synthetic starch reaction liquid, the separation method comprising:

[0098] (1) 10 L of the artificial synthetic starch reaction liquid is adjusted to a pH of 9, and then poured into a feed liquid tank, and connected to an external pressure type membrane separation and concentration device through a delivery pump Figure 2 The starch concentration in the reaction liquid is 1.65 g / L, the BSA equivalent concentration of the enzyme is 0.95 g / L, and the glucose equivalent concentration of monosaccharide is about 0.53 g / L, the membrane assembly of the external pressure type membrane separation and concentration device is a PVDF membrane tube, the total membrane area is 0.3 m 2 , the pore size is 0.22 μm, the membrane tube is uniformly distributed along the radial direction and the circumferential direction, the stirring paddle is Figure 3 The pressure of the separation and concentration device is set to 0.1 MPa, the stirring is started, the filtration is carried out at a temperature of 25℃, after 3h of filtration, the deionized water is backwashed for 5 min, the filtration is continued for 1h, the stirring is stopped, the pump is turned off, the pressure is released, the microfiltration is stopped, the concentrated liquid volume is 0.91 L, the starch concentration in the concentrated liquid is 16.53 g / L, the starch concentration multiple is about 10.02, and the starch yield is about 91.16%; the glucose equivalent concentration of monosaccharide in the concentrated liquid is about 0.05 g / L, the monosaccharide removal rate is about 99.14%, the permeate volume is about 8.99 L, the BSA equivalent concentration of the enzyme in the permeate is about 0.55 g / L, and the enzyme recovery rate is about 52.04%;

[0099] (2) The concentrated liquid is centrifuged and dried to obtain starch product with a mass of 13.84g and a starch product yield of 83.88%. The permeate is ultrafiltered to obtain enzyme concentrate with a 30kDA PVDF ultrafiltration membrane and the enzyme concentration of BSA equivalent in the enzyme concentrate is 2.25g / L.

[0100] Example 9

[0101] This embodiment provides a method for separating a synthetic starch reaction solution, the separation method comprising:

[0102] (1) After adjusting the pH of 25L of synthetic starch reaction solution to 9, pour it into the feed tank and then transfer it to the feed pump. Figure 3 The feed inlet pipe of the internal pressure membrane separation and concentration device shown is connected. The starch concentration in the reaction solution is 1.25 g / L, the BSA equivalent concentration of the enzyme is 0.87 g / L, and the glucose equivalent concentration of the monosaccharide is approximately 0.71 g / L. The membrane module of the internal pressure membrane separation and concentration device is a PVDF membrane with a total membrane area of ​​0.3 m². 2 The pore size is 0.22 μm, and the stirring paddle is... Figure 4 The stirring paddle shown was used. The pressure of the separation and concentration device was set to 0.1 MPa. Stirring was started, and filtration was performed at 25°C. Backwashing was performed for 5 minutes whenever the filtration flux decreased by 40%. After 11 hours of filtration, stirring was stopped, the pump was turned off, pressure was released, and microfiltration was stopped. The volume of the concentrated liquid obtained was 1.12 L. The starch concentration in the concentrated liquid was 25.01 g / L, the starch concentration factor was approximately 20.01, and the starch yield was approximately 89.63%. The glucose equivalent concentration of monosaccharides in the concentrated liquid was approximately 0.06 g / L, the monosaccharide removal rate was approximately 99.62%, the permeate volume was approximately 23.78 L, the BSA equivalent concentration of enzymes in the permeate was approximately 0.53 g / L, and the enzyme recovery rate was approximately 57.94%.

[0103] (2) The concentrated liquid is centrifuged and dried to obtain starch product with a starch product mass of 25.83g and a starch product yield of 82.66%. The permeate is ultrafiltered to obtain enzyme concentrate with a 30kDA PVDF ultrafiltration membrane and the BSA equivalent concentration of enzyme in the enzyme concentrate is 2.11g / L.

[0104] Example 10

[0105] This embodiment provides a method for separating the reaction solution of artificially synthesized starch. The separation method is the same as that in Example 1, except that the freezing and thawing steps of the reaction solution are not performed.

[0106] The obtained concentrated liquid of each stage has a volume of about 0.27 L, a starch concentration of 14.3 g / L, a starch concentration ratio of 9.35, a concentration yield of 10.09%, and a product yield of 9.44%; the concentrated liquid of the second stage has a volume of 0.71 L, a starch concentration of 16.69 g / L, a starch concentration ratio of 10.91, a concentration yield of 30.98%, and a product yield of 28.52%; the concentrated liquid of the third stage has a volume of 0.81 L, a starch concentration of 18.12 g / L, a starch concentration ratio of 11.84, a concentration yield of 38.37%, and a product yield of 35.30%; the concentrated liquid of the fourth stage has a volume of 0.92 L, a starch concentration of 6.46 g / L, a starch concentration ratio of 4.22, a concentration yield of 15.54%, and a product yield of 14.35%; the total starch concentration yield is about 94.98%, and the total starch product yield is about 87.61%; the volume of the permeate of the fourth stage device is about 22.50 L, the BSA equivalent concentration of the enzyme in the permeate is about 0.58 g / L, and the recovery rate of the enzyme is about 59.32%;

[0107] The concentrated liquid of each stage is subjected to centrifugation and drying to obtain a starch product, the total mass of the starch product is 33.51 g, and the starch product yield is 87.61%; the permeate is subjected to ultrafiltration to obtain an enzyme concentrate, the ultrafiltration filter membrane is a PVDF ultrafiltration membrane with a molecular weight of 30 kDA, and the BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.32 g / L.

[0108] Example 11

[0109] The separation method of the artificial synthetic starch reaction liquid provided in this example is the same as that in Example 2, except that the distance between the stirring paddle tip of the membrane separation and concentration device and the membrane surface is 2 cm.

[0110] The obtained concentrated liquid has a volume of 2.1 L, a starch concentration of 5.81 g / L, a starch concentration ratio of about 3.80, and a starch yield of about 79.74%; the glucose equivalent concentration of monosaccharides in the concentrated liquid is about 0.12 g / L, the monosaccharide removal rate is about 96.88%, the volume of the permeate is about 7.9 L, the BSA equivalent concentration of the enzyme in the permeate is about 0.54 g / L, and the recovery rate of the enzyme is about 48.48%;

[0111] The concentrated liquid is subjected to centrifugation and drying to obtain a starch product, the mass of the starch product is 10.86 g, and the starch product yield is 70.98%; the permeate is subjected to ultrafiltration to obtain an enzyme concentrate, the ultrafiltration filter membrane is a PVDF ultrafiltration membrane with a molecular weight of 30 kDA, and the BSA equivalent concentration of the enzyme in the enzyme concentrate is 2.13 g / L.

[0112] Comparative Example 1

[0113] The separation method of the artificial synthetic starch reaction liquid provided in this comparative example is the same as that in Example 2, except that the distance between the stirring paddle tip of the membrane separation and concentration device and the membrane surface is 2 cm.​ The internal pressure type conventional membrane separation device shown is used for separation, no stirring device is arranged in the device, and the rest is the same as that in Example 2;

[0114] The volume of the concentrated liquid is 3.9 L, the starch concentration in the concentrated liquid is 2.57 g / L, the starch concentration multiple is about 1.68, and the starch yield is about 65.51%; the glucose equivalent concentration of monosaccharide in the concentrated liquid is about 0.15 g / L, the monosaccharide removal rate is about 92.78%, the volume of the permeate is about 6.1 L, the BSA equivalent concentration of the enzyme in the permeate is about 0.47 g / L, and the enzyme recovery rate is about 32.58%;

[0115] The concentrated liquid is subjected to centrifugation and drying to obtain a starch product, the mass of the starch product is 8.52 g, and the starch product yield is 55.69%; the permeate is subjected to ultrafiltration to obtain an enzyme concentrated liquid, the ultrafiltration filter membrane is a PVDF ultrafiltration membrane with a molecular weight of 30 kDA, and the BSA equivalent concentration of the enzyme in the enzyme concentrated liquid is 1.89 g / L.

[0116] Test method

[0117] The starch concentration is determined by an oxidase method, the enzyme concentration is determined by a Coomassie brilliant blue method, the monosaccharide concentration is determined by a high performance liquid chromatography (HPLC) method, an amino column (4.6 mm*250 mm, 5 μm) is selected as a chromatographic column, a mobile phase is acetonitrile-water (volume ratio 70:30), a flow rate is 1.0 mL / min, a column temperature is 30 DEG C, and a differential refractive index detector is used for detection; sample liquid is filtered through a 0.22 μm filter membrane and then is injected, and an external standard method is used to calculate the glucose equivalent concentration of monosaccharide. The phosphate concentration is determined by a molybdenum-antimony anti-spectrophotometric method.

[0118] (1) It can be seen from Examples 1 to 9 that, by optimizing the process conditions and the multi-stage membrane separation process, the technical effects of efficient starch concentration, deep removal of monosaccharide and phosphate, and effective recovery of enzyme can be achieved, wherein when the pH is adjusted to 9 and the multi-stage membrane separation is used, the starch concentration multiple can be increased to more than 9.35, the monosaccharide removal rate can be more than 98%, and the enzyme recovery rate is maintained between 39% and 68%, which significantly optimizes the separation efficiency.

[0119] (2) It can be seen from Examples 1 and 10, and Examples 2 and 11 that, by further freezing and thawing and setting the distance between the stirring paddle and the membrane surface, better separation effects can be achieved. In Examples 1 and 2, freezing and thawing are used, and compared with Examples 3 to 10 which do not perform freezing and thawing, the removal efficiency of monosaccharide and phosphate is improved while the total starch yield is maintained; compared with the setting of the distance between the stirring paddle and the membrane surface of 2 cm in Example 11, the distance between the stirring paddle and the membrane surface in Example 2 is optimized, which effectively reduces the membrane surface pollution, improves the filtration flux and the starch yield.

[0120] (3) As can be seen from Example 2 and Comparative Example 1, the present application can obtain the technical effects of higher starch concentration multiple, starch yield and monosaccharide removal rate by providing the stirring device in the membrane separation and concentration device, while when the stirring device is not used, it cannot realize efficient mass transfer on the membrane surface, leading to intensified membrane pollution, decreased filtration flux, and thus reduced starch yield and poor monosaccharide removal rate. In Example 2, due to the presence of the stirring device, the starch concentration multiple is 12.92, the yield is 92.99%, and the monosaccharide removal rate is 99.11%, while in Comparative Example 1, due to the lack of stirring, it is difficult to maintain stable separation efficiency, and the key indicators are significantly inferior to those of Example 2.

[0121] In summary, by reasonably selecting the type of membrane separation device, optimizing the membrane module parameters and process conditions, providing the stirring device and the supporting pretreatment / backwashing steps, and simultaneously using 30kDA PVDF ultrafiltration membrane to recover the enzyme, the present application realizes efficient separation and purification of starch in the artificial synthetic starch reaction solution, deep removal of monosaccharide and phosphate, and effective recovery of enzyme, and has the technical effects of high separation efficiency, high product purity and strong process stability, providing a reliable scheme for the industrialization of artificial synthetic starch separation.

[0122] The applicant declares that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by any person skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for separating a synthetic starch reaction solution, characterized in that, The separation method includes: (1) The synthetic starch reaction solution is filtered through at least one membrane separation filter, where the synthetic starch is retained and the remaining components in the reaction solution permeate. The membrane separation filter is stirred on the retention side to obtain a concentrated solution and a permeate solution respectively. (2) The concentrate is post-processed to obtain the artificially synthesized starch, and the permeate is post-processed to obtain the enzyme concentrate.

2. The separation method according to claim 1, characterized in that, The separation method further includes freezing the artificial starch reaction solution, thawing it, and then performing membrane separation filtration. Preferably, the freezing temperature is -80 to -10°C; Preferably, the freezing time is ≥4 hours.

3. The separation method according to claim 1 or 2, characterized in that, Before membrane separation and filtration of the artificially synthesized starch reaction liquid, the pH value is adjusted to 8-10; Preferably, the pH adjusting agent includes a sodium carbonate solution.

4. The separation method according to any one of claims 1 to 3, characterized in that, The membrane separation filtration is a cross-flow filtration, in which the intercepted side liquid flows from top to bottom; Preferably, the membrane pore size of the membrane separation filter is 0.1~50μm; Preferably, in the multi-stage membrane separation filtration, the pore size of each stage of the membrane decreases progressively. Preferably, the pressure difference of the membrane separation filtration is 0.1~0.15 MPa; Preferably, the temperature of the membrane separation filtration is 20~35 ℃.

5. The separation method according to any one of claims 1 to 4, characterized in that, When the filtration flux of the membrane separation filtration decreases by 20-40%, forward flushing and / or back flushing are performed. Preferably, the post-treatment of the concentrate includes washing, dehydration and drying performed sequentially; Preferably, the washing process includes adding a washing solution and stirring, followed by membrane separation and filtration until the volume of the washing permeate is greater than or equal to the volume of the washing solution, thus completing one washing cycle. Preferably, the washing is repeated 1 to 3 times; Preferably, the stirring is performed for 5 to 10 minutes; Preferably, the washing solution includes one or a combination of at least two of the following: deionized water, EDTA aqueous solution, urea aqueous solution, SDS aqueous solution, or sodium hydroxide aqueous solution; Preferably, the volume of the washing liquid is 0.25 to 1.5 times that of the synthetic starch reaction solution.

6. The separation method according to any one of claims 1 to 5, characterized in that, The permeate and washing solution are separated by ultrafiltration to separate the enzyme and small molecule impurities in the permeate, resulting in an enzyme concentrate. Preferably, the ultrafiltration membrane is an aqueous membrane with a molecular weight cutoff range of 20~50kDa.

7. A separation apparatus for use in the separation method according to any one of claims 1 to 6, characterized in that, The separation device includes at least one microfiltration device and one ultrafiltration device. The artificially synthesized starch reaction solution is injected into the inlet of the microfiltration device, and the concentrated solution and permeate are obtained from the outlet of the microfiltration device. The permeate is injected into the ultrafiltration device to obtain an enzyme concentrate. The microfiltration device includes an external pressure membrane separation and concentration device or an internal pressure membrane separation and concentration device.

8. The separation device according to claim 7, characterized in that, When the microfiltration device is a multi-stage microfiltration device, the microfiltration devices at each stage are connected in series, and the permeate of the previous stage microfiltration device is injected into the feed inlet of the next stage microfiltration device.

9. The separation device according to claim 7 or 8, characterized in that, Both the external pressure membrane separation and concentration device and the internal pressure membrane separation and concentration device include a stirring device, which is located on the retention side; Preferably, the distance between the tip of the stirring paddle and the film surface of the stirring device is no more than 1.5 cm; Preferably, the impeller blades include blades with a structure in which the cross-sectional area near the film surface is smaller than the cross-sectional area near the stirring shaft. Preferably, the stirring paddle blades further include wavy blades, which are arranged parallel to the membrane surface.

10. The separation apparatus according to any one of claims 7 to 9, characterized in that, The membrane module in the microfiltration device includes any one of spiral wound membrane, hollow fiber membrane, or tubular membrane, preferably a hollow fiber membrane or a tubular membrane. Preferably, the filter membrane material of the membrane module includes any one of stainless steel filter membrane, ceramic filter membrane, or organic filter membrane; Preferably, the filter membrane material with a pore size ≥ 5 μm is a stainless steel filter membrane or a ceramic filter membrane, and the filter membrane material with a pore size < 5 μm is any one of PVDF, PES, PS or MCE.

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