Biomass-sourced succinic acid as well as preparation method and application thereof

Abstract

The invention provides biomass-sourced succinic acid as well as a preparation method and application thereof. The biomass-sourced succinic acid comprises succinic acid, iron ions, chloride ions, sulfate ions and phosphate ions. The mass content of iron ions in the succinic acid derived from the biomass is 0.01-5 ppm, the mass content of chloride ions in the succinic acid derived from the biomass is 0.1-15 ppm, and the mass content of sulfate ions in the succinic acid derived from the biomass is 0.1-100 ppm; the mass content of the phosphate ions is 0.1 to 200 ppm. The biomass-derived succinic acid provided by the invention contains inorganic ions with a specific content, the succinic acid is high in purity and low in inorganic salt content, and the inorganic salt content is obviously lower than the index requirement of GB / T34686-2017 on superior succinic acid. The biomass-derived succinic acid is used for preparing the PBS resin, so that the PBS resin has higher mechanical properties and aging resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of biochemistry, and particularly relates to succinic acid derived from biomass, a preparation method thereof, and an application thereof. Background Art

[0002] Succinic acid, also known as amber acid, is an excellent platform compound. Bio-based succinic acid is listed by the United States as one of the 12 most valuable platform compounds in the future, and has a wide range of uses in the fields of chemical engineering, materials, medicine, and food. It is a raw material for the biodegradable material PBS (polybutylene succinate). There are mainly two production methods for succinic acid. One is the traditional chemical synthesis method, and the other is the new microbial fermentation method. The traditional chemical synthesis method is affected by the price of petroleum, and the cost remains high. At the same time, its manufacturing process does not meet the strategic goal of carbon reduction in today's society. The microbial fermentation method uses renewable biomass resources as raw materials, and the production process is green and resource-saving, and has attracted much attention in the industry in recent years.

[0003] The production process of preparing succinic acid by the microbial fermentation method includes two stages. The first stage is to ferment with specific microorganisms to obtain a succinic acid fermentation broth, and the second stage is to treat the succinic acid fermentation broth by some physical and chemical methods to separate the target product succinic acid from these impurities and extract it from the fermentation broth. For example, CN106316836A discloses a method for preparing succinic acid, and the steps are as follows: (1) culturing by the microbial fermentation method to obtain a sodium succinate fermentation broth; (2) adjusting the pH value of the fermentation broth containing succinic acid to 5.5 - 6.5, then performing solid-liquid separation on the succinic acid fermentation broth and removing part of the protein and pigment to obtain a clarified fermentation broth, concentrating and crystallizing the fermentation broth, then dissolving the crystals, decolorizing the dissolved liquid with activated carbon, acidifying, crystallizing, and drying the obtained decolorized fermentation broth to finally obtain succinic acid.

[0004] Currently, the production of succinic acid by the microbial fermentation method is mainly carried out under neutral conditions. Due to the continuous production of the product succinic acid, the pH value of the system continuously decreases, which is not conducive to the growth of the strain and causes a decrease in the carbon source utilization rate. In order to maintain the pH value stability of the fermentation system, alkaline substances such as ammonia water and sodium hydroxide are added for neutralization during the fermentation process to convert succinic acid into succinate. The succinate needs to be acidified with acid again in the purification stage. This process not only consumes a large amount of acid and alkali, but also generates more impurity inorganic salts. Therefore, a large amount of inorganic salt impurities are generated in succinic acid due to the introduction of fermentation nutrients and acid and alkali, which are difficult to handle, mainly including Fe 2+ , Cl - , SO4 2- , PO4 3-etc. The currently disclosed succinic acid production process cannot effectively remove inorganic salt impurities in the system. Therefore, it is difficult to obtain succinic acid with high purity and low inorganic salt content, which in turn leads to insufficient mechanical properties and anti-aging properties of the PBS resin prepared therefrom.

[0005] Therefore, how to obtain bio-based succinic acid with high purity and low inorganic salt content is an urgent problem to be solved in this field. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a succinic acid derived from biomass, its preparation method and application. The succinic acid derived from biomass contains specific contents of iron ions, chloride ions, sulfate ions and phosphate ions, and has the characteristics of high purity of succinic acid and low inorganic salt content, so that the PBS resin prepared therefrom has excellent anti-aging properties and mechanical properties.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a succinic acid derived from biomass, which includes succinic acid (pure substance), iron ions, chloride ions, sulfate ions and phosphate ions; the mass content of iron ions in the succinic acid derived from biomass is 0.01 - 5 ppm, the mass content of chloride ions is 0.1 - 15 ppm, the mass content of sulfate ions is 0.1 - 100 ppm, and the mass content of phosphate ions is 0.1 - 200 ppm.

[0009] The succinic acid derived from biomass provided by the present invention contains specific contents of iron ions, chloride ions, sulfate ions and phosphate ions, has high purity of succinic acid and low inorganic salt content, and the inorganic salt content is significantly lower than the index requirements for first-class succinic acid in GB / T 34686 - 2017. The succinic acid derived from biomass is used to prepare PBS resin, which can make the PBS resin have better anti-aging properties and higher mechanical properties.

[0010] The iron ions in the present invention include Fe 2+ and Fe 3+ , and the iron ions in the succinic acid derived from biomass are mainly Fe 2+ .

[0011] Specifically, the iron ions (Fe 2+ and Fe 3+) has a mass content of 0.01 - 5 ppm. For example, it can be 0.015 ppm, 0.02 ppm, 0.03 ppm, 0.05 ppm, 0.08 ppm, 0.1 ppm, 0.3 ppm, 0.5 ppm, 0.8 ppm, 1 ppm, 1.5 ppm, 2 ppm, 2.5 ppm, 3 ppm, 3.5 ppm, 4 ppm or 4.5 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range. Further preferably, it is 0.1 - 3 ppm, and more preferably 1 - 2.5 ppm.

[0012] The mass content of chloride ions (Cl - ) in the succinic acid from biomass sources is 0.1 - 15 ppm. For example, it can be 0.15 ppm, 0.2 ppm, 0.3 ppm, 0.5 ppm, 0.8 ppm, 1 ppm, 1.5 ppm, 2 ppm, 2.5 ppm, 3 ppm, 3.5 ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, 10 ppm, 11 ppm, 12 ppm, 13 ppm or 14 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range. Further preferably, it is 0.5 - 14.5 ppm, and more preferably 4 - 14 ppm.

[0013] The mass content of sulfate ions (SO4 2- ) in the succinic acid from biomass sources is 0.1 - 100 ppm. For example, it can be 0.15 ppm, 0.3 ppm, 0.5 ppm, 1 ppm, 2 ppm, 5 ppm, 8 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, 65 ppm, 70 ppm, 75 ppm, 80 ppm, 85 ppm, 88 ppm, 90 ppm, 92 ppm, 95 ppm or 98 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range. Further preferably, it is 10 - 95 ppm, and more preferably 60 - 90 ppm.

[0014] The mass content of phosphate ions (PO4 3-) has a mass content of 0.1 - 200 ppm, for example, it can be 0.2 ppm, 0.5 ppm, 1 ppm, 2 ppm, 5 ppm, 8 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 80 ppm, 100 ppm, 120 ppm, 150 ppm, 180 ppm or 190 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range. Further preferably, it is 50 - 190 ppm, and more preferably 120 - 180 ppm.

[0015] In the present invention, "ppm" represents parts per million, and 1 ppm represents one in a million.

[0016] Exemplarily, the content of iron ions in the succinic acid from biomass sources can be tested by the methods in GB / T34686 - 2017 and GB / T 9739 - 2006; the content of chloride ions can be tested by the methods in GB / T 34686 - 2017 and GB / T9729 - 2007; the content of sulfate ions can be tested by the methods in GB / T 34686 - 2017; the content of phosphate ions can be tested by the methods in GB / T9727 - 2007.

[0017] It should be noted that the tests for the mass contents of iron ions, chloride ions, sulfate ions and phosphate ions in the succinic acid from biomass sources are not limited to the methods listed above.

[0018] Preferably, the mass percentage content (purity) of succinic acid in the succinic acid from biomass sources is ≥99.7%, for example, it can be 99.72%, 99.75%, 99.78%, 99.8%, 99.82%, 99.85%, 99.88%, 99.9%, 99.92%, 99.93%, 99.94%, 99.95%, 99.96%, 99.97%, 99.98%, 99.99% or 99.999%, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range. Further preferably, it is ≥99.75%.

[0019] Preferably, the succinic acid from biomass sources further includes water and / or heavy metals.

[0020] Preferably, the mass content of water in the succinic acid derived from biomass is 0.01 - 2000 ppm, for example, it can be 0.05 ppm, 0.1 ppm, 0.5 ppm, 1 ppm, 5 ppm, 10 ppm, 20 ppm, 30 ppm, 50 ppm, 80 ppm, 100 ppm, 200 ppm, 300 ppm, 500 ppm, 800 ppm, 1000 ppm, 1200 ppm, 1500 ppm or 1800 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.1 - 700 ppm.

[0021] In the present invention, the heavy metal refers to a metal with a density > 4.5 g / cm 3 , such as Pb.

[0022] Preferably, the mass content of heavy metals in the succinic acid derived from biomass is 0.01 - 10 ppm, for example, it can be 0.02 ppm, 0.03 ppm, 0.05 ppm, 0.08 ppm, 0.1 ppm, 0.2 ppm, 0.5 ppm, 0.8 ppm, 1 ppm, 2 ppm, 3 ppm, 3.5 ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm or 9 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.02 - 0.3 ppm.

[0023] Preferably, the content of ignition residue of the succinic acid derived from biomass is 1 - 200 ppm, for example, it can be 1.5 ppm, 2 ppm, 5 ppm, 8 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 80 ppm, 100 ppm, 120 ppm, 150 ppm, 180 ppm or 190 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 10 - 130 ppm.

[0024] Exemplarily, the mass percentage content (purity), water content, heavy metal content, ignition residue content, etc. of the succinic acid derived from biomass can be tested and obtained by the method in GB / T 34686 - 2017. The water content can also be tested by the method of heat loss on ignition.

[0025] It should be noted that the testing of the water content and heavy metal content of the succinic acid derived from biomass is not limited to the methods listed above.

[0026] Second aspect, the present invention provides a method for preparing succinic acid from biomass as described in the first aspect, and the preparation method includes the following steps:

[0027] Inoculate the seed liquid of the succinic acid-producing strain into a culture medium for fermentation to obtain a fermentation broth;

[0028] The fermentation broth is ultrafiltered to obtain a permeate;

[0029] Use an extractant to perform multi-stage forward cross-flow extraction on the permeate to obtain a succinic acid-loaded organic phase;

[0030] Use an anti-extractant to perform multi-stage reverse cross-flow extraction on the succinic acid-loaded organic phase to obtain an aqueous succinic acid solution;

[0031] The aqueous succinic acid solution is concentrated and crystallized to obtain the succinic acid from biomass.

[0032] The preparation method provided by the present invention uses renewable biomass resources as raw materials, obtains a fermentation broth containing succinic acid through fermentation, and then designs a combined purification process including ultrafiltration, multi-stage forward cross-flow extraction, and multi-stage reverse cross-flow extraction, effectively reducing the content of impurities such as inorganic salts in the fermentation broth, and omitting steps such as the calcium salt method, ammonium salt method, ion exchange, decolorization, and electrodialysis used in traditional purification methods, avoiding the introduction of impurities, and obtaining high-quality succinic acid from biomass.

[0033] Preferably, the succinic acid-producing strain includes Escherichia coli, Actinobacillus succinogenes, or Anaerobiospirillum.

[0034] Preferably, the inoculation amount of the seed liquid is 1-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0035] In the present invention, the term "inoculation amount" refers to the volume percentage of the seed liquid relative to the culture medium.

[0036] Preferably, the pH value of the fermentation is 6.0-7.5, for example, it can be 6.2, 6.5, 6.6, 6.8, 7.0, 7.2, or 7.4, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0037] As a preferred technical solution of the present invention, an alkaline neutralizing agent is added to the system during the fermentation process to keep the pH value of the fermentation at 6.0-7.5.

[0038] Preferably, the alkaline neutralizing agent includes any one or a combination of at least two of sodium hydroxide, sodium carbonate, magnesium carbonate, magnesium chloride, calcium carbonate, and calcium chloride.

[0039] Preferably, the stirring speed of the fermentation is 100 - 600 r / min. For example, it can be 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, or 550 r / min, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0040] Preferably, the temperature of the fermentation is 30 - 40 °C. For example, it can be 31 °C, 32 °C, 33 °C, 34 °C, 35 °C, 36 °C, 37 °C, 38 °C, or 39 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0041] Preferably, the time of the fermentation is 20 - 70 h. For example, it can be 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 38 h, 40 h, 42 h, 45 h, 48 h, 50 h, 52 h, 55 h, 58 h, 60 h, 62 h, 65 h, or 68 h, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0042] Preferably, the fermentation includes aerobic fermentation and anaerobic fermentation carried out in sequence.

[0043] As a preferred technical solution of the present invention, aerobic fermentation is first carried out during the fermentation process. At this stage, the growth of the bacteria reaches the stationary phase, and then it enters the anaerobic fermentation stage to promote the efficient production of succinic acid and improve the yield of succinic acid.

[0044] Preferably, the dissolved oxygen content of the aerobic fermentation is 20% - 50%. For example, it can be 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, or 48%, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0045] In the present invention, the term "dissolved oxygen content" refers to the volume percentage of oxygen in the fermentation broth.

[0046] Preferably, the temperature of the aerobic fermentation is 33-40 °C, for example, it can be 34 °C, 35 °C, 36 °C, 37 °C, 38 °C or 39 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0047] Preferably, the stirring speed of the aerobic fermentation is 300-500 r / min, for example, it can be 320 r / min, 350 r / min, 380 r / min, 400 r / min, 420 r / min, 450 r / min or 480 r / min, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0048] Preferably, the time of the aerobic fermentation is 6-12 h, for example, it can be 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h or 11.5 h, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0049] Preferably, the dissolved oxygen content of the anaerobic fermentation is 0-0.5%, for example, it can be 0, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4% or 0.45%, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0050] Preferably, the temperature of the anaerobic fermentation is 30-40 °C, for example, it can be 31 °C, 32 °C, 33 °C, 34 °C, 35 °C, 36 °C, 37 °C, 38 °C or 39 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0051] Preferably, the stirring speed of the anaerobic fermentation is 200-300 r / min, for example, it can be 210 r / min, 220 r / min, 230 r / min, 240 r / min, 250 r / min, 260 r / min, 270 r / min, 280 r / min or 290 r / min, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0052] Preferably, the time of the anaerobic fermentation is 30 - 50 h, for example, it can be 32 h, 35 h, 36 h, 38 h, 40 h, 42 h, 45 h, 46 h or 48 h, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0053] In the present invention, the fermentation broth is ultrafiltered to remove thalli and insoluble solid impurities, and a permeate is obtained.

[0054] Preferably, the pore size of the ultrafiltration membrane used for the ultrafiltration is 20 - 80 nm, for example, it can be 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm or 75 nm, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0055] Preferably, the temperature of the ultrafiltration is 40 - 60 °C, for example, it can be 42 °C, 45 °C, 48 °C, 50 °C, 52 °C, 55 °C or 58 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0056] Preferably, the concentration multiple of the ultrafiltration is 10 - 40 times, for example, it can be 12 times, 15 times, 18 times, 20 times, 22 times, 25 times, 28 times, 30 times, 32 times, 35 times or 38 times, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0057] Preferably, the extractant includes a combination of a phosphoric acid ester complexing agent and a co - solvent.

[0058] Preferably, the phosphoric acid ester complexing agent has a structure shown in Formula I:

[0059]

[0060] In Formula I, R1 is selected from any one of C1 - C10 straight - chain or branched - chain alkyl groups;

[0061] In Formula I, R2 is selected from any one of H, C1 - C10 straight - chain or branched - chain alkyl groups;

[0062] In Formula I, R3 is selected from any one of C1 - C10 straight - chain or branched - chain alkyl groups, hydroxyl groups, C1 - C10 alkoxy groups.

[0063] Among them, the C1-C10 linear or branched alkyl groups can all be linear or branched alkyl groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10. Exemplarily, they include but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-methylbutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, neohexyl, 2-ethylhexyl, n-octyl, isooctyl, n-heptyl, n-nonyl, n-decyl, etc.

[0064] The C1-C10 alkoxy groups can all be linear or branched alkoxy groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10. Specific examples thereof can be monovalent groups obtained by connecting the above-mentioned examples of linear or branched alkyl groups with O.

[0065] Preferably, the phosphate complexing agent includes any one or a combination of at least two of diisooctyl phosphate, dimethylheptyl methylphosphonate, and mono(2-ethylhexyl) 2-ethylhexyl phosphate.

[0066] Preferably, the cosolvent includes alcohol solvents, and more preferably C6-C12 (such as C7, C8, C9, C10, or C11, etc.) alcohol solvents.

[0067] As a preferred technical solution of the present invention, in the multi-stage forward cross-flow extraction, a phosphate complexing agent having the structure shown in Formula I is used. The P=O group in its molecular structure belongs to a Lewis basic functional group, and the P=O bond has polarity, is stable in nature, has a large bond energy, and has strong complexing ability, and can complex with succinic acid (containing the Lewis acidic group -COOH). At the same time, an alcohol solvent is used as a cosolvent in the extractant, and it synergistically interacts with the phosphate complexing agent to form a mixed extractant system, significantly improving the effect of extracting succinic acid from the permeate.

[0068] Preferably, the cosolvent includes any one or a combination of at least two of n-heptanol, isooctanol, n-nonanol, and n-decanol.

[0069] Preferably, the volume ratio of the phosphate complexing agent to the cosolvent is 1:(0.1-10), and for example, it can be 1:0.2, 1:0.5, 1:0.8, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10, etc.

[0070] Preferably, the volume ratio of the extractant to the permeate is (2-7):1, and for example, it can be 2.5:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1, 5.5:1, 6:1, or 6.5:1, etc., and more preferably (3-5):1.

[0071] Preferably, the number of stages of the multi-stage forward cross-flow extraction is 2 - 5 stages, such as 3 stages, 4 stages, etc., and more preferably 2 - 3 stages.

[0072] Preferably, the temperature of the multi-stage forward cross-flow extraction is 20 - 60 °C. For example, it can be 22 °C, 25 °C, 28 °C, 30 °C, 32 °C, 35 °C, 38 °C, 40 °C, 42 °C, 45 °C, 48 °C, 50 °C, 52 °C, 55 °C or 58 °C, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list all the specific point values included in the range.

[0073] Preferably, the number of stages of the multi-stage counter-current cross-flow extraction is 2 - 6 stages, such as 3 stages, 4 stages or 5 stages, etc., and more preferably 3 - 5 stages.

[0074] Preferably, the stripping agent for the first-stage counter-current cross-flow extraction is water, and the stripping agents for the 2 - nth stage counter-current cross-flow extraction are alkaline salt aqueous solutions; n represents an integer from 3 to 5, such as 3, 4 or 5.

[0075] As a preferred technical solution of the present invention, in the multi-stage counter-current cross-flow extraction, water is used as the stripping agent in the first stage. As the stripping progresses, the succinic acid in the water increases and the pH of the system gradually decreases, thus affecting the solubility of succinic acid in water. Using an alkaline salt aqueous solution as the stripping agent for the second stage and subsequent stages can regulate the pH value of the solution, thereby increasing the solubility of succinic acid, promoting the stripping process, increasing the stripping yield, and obtaining succinic acid from the biomass with a lower inorganic salt content.

[0076] Preferably, the alkaline salt includes any one or a combination of at least two of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0077] Preferably, the mass percentage content of the alkaline salt in the alkaline salt aqueous solution is 5% - 12%. For example, it can be 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5% or 11%, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list all the specific point values included in the range.

[0078] Preferably, the volume ratio of the stripping agent to the succinic acid-loaded organic phase is (1.5 - 6):1. For example, it can be 2:1, 2.5:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1 or 5.5:1, etc., and more preferably (3 - 5):1.

[0079] Preferably, the temperature of the multi-stage counter-current extraction is 40-80°C, for example, it can be 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C or 78°C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0080] Preferably, the temperature of the concentration is 60-80°C, for example, it can be 62°C, 65°C, 68°C, 70°C, 72°C, 75°C or 78°C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0081] Preferably, the method of concentration includes evaporation concentration.

[0082] Preferably, the system pressure of the concentration is 10-40 kPa, for example, it can be 12 kPa, 15 kPa, 18 kPa, 20 kPa, 22 kPa, 25 kPa, 28 kPa, 30 kPa, 32 kPa, 35 kPa or 38 kPa, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0083] Preferably, the multiple of the concentration is 2-10 times, for example, it can be 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times or 9.5 times, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0084] Preferably, the temperature of the crystallization is 10-30°C, for example, it can be 12°C, 15°C, 18°C, 20°C, 22°C, 25°C or 28°C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0085] Preferably, the system pressure of the crystallization is 60-80 kPa, for example, it can be 62 kPa, 65 kPa, 68 kPa, 70 kPa, 72 kPa, 75 kPa or 78 kPa, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0086] Preferably, after the crystallization, it further includes the steps of centrifugal separation and drying.

[0087] Preferably, the drying temperature is 75 - 85°C, for example, it can be 76°C, 78°C, 80°C, 82°C or 84°C, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0088] Preferably, after the crystallization, it further includes the steps of redissolution and recrystallization.

[0089] Preferably, the solvent used for redissolution includes water.

[0090] Preferably, the redissolution temperature is 40 - 80°C, for example, it can be 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C or 78°C, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0091] Preferably, the system pressure for redissolution is 5 - 30 kPa, for example, it can be 6 kPa, 8 kPa, 10 kPa, 12 kPa, 15 kPa, 18 kPa, 20 kPa, 22 kPa, 25 kPa or 28 kPa, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0092] Preferably, the recrystallization temperature is 10 - 30°C, for example, it can be 12°C, 15°C, 18°C, 20°C, 22°C, 25°C or 28°C, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0093] Preferably, the system pressure for recrystallization is 60 - 80 kPa, for example, it can be 62 kPa, 65 kPa, 68 kPa, 70 kPa, 72 kPa, 75 kPa or 78 kPa, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0094] Preferably, after the recrystallization, it further includes the steps of centrifugal separation and drying.

[0095] In a preferred technical solution, the preparation method of the succinic acid from biomass includes the following steps:

[0096] (1) Inoculate the seed liquid of the succinic acid-producing strain into the culture medium for fermentation at an inoculation amount of 1 - 10% to obtain a fermentation broth;

[0097] The pH value of the fermentation is 6.0 - 7.5, including aerobic fermentation and anaerobic fermentation carried out successively. The temperature of the aerobic fermentation is 33 - 40°C, the dissolved oxygen content is 20% - 50%, the stirring speed is 300 - 500 r / min, and the time is 6 - 12 h; the temperature of the anaerobic fermentation is 30 - 40°C, the dissolved oxygen content is 0 - 0.5%, the stirring speed is 200 - 300 r / min, and the time is 30 - 50 h;

[0098] (2) Ultrafilter the fermentation broth. The pore size of the ultrafiltration membrane is 20 - 80 nm, the temperature is 40 - 60°C, and the concentration multiple is 10 - 40 times to obtain a permeate;

[0099] (3) Use an extractant to perform multi-stage forward cross-flow extraction on the permeate to obtain a succinic acid-loaded organic phase;

[0100] The extractant includes a phosphoric acid ester complexing agent and a co-solvent with a volume ratio of 1:(0.1 - 10). The phosphoric acid ester complexing agent has the structure shown in Formula I, and the co-solvent is a C6 - C12 alcohol solvent; the volume ratio of the extractant to the permeate is (3 - 5):1;

[0101] The number of stages of the multi-stage forward cross-flow extraction is 2 - 3 stages, and the temperature is 20 - 60°C;

[0102] (4) Use a stripping agent to perform multi-stage reverse cross-flow extraction on the succinic acid-loaded organic phase to obtain an aqueous succinic acid solution;

[0103] The volume ratio of the stripping agent to the succinic acid-loaded organic phase is (3 - 5):1;

[0104] The number of stages of the multi-stage reverse cross-flow extraction is 3 - 5 stages, and the temperature is 40 - 80°C; the stripping agent for the first-stage reverse cross-flow extraction is water, and the stripping agent for the 2 - nth stage reverse cross-flow extraction is an alkaline salt aqueous solution. The mass percentage content of the alkaline salt in the alkaline salt aqueous solution is 5% - 12%; n represents an integer from 3 to 5;

[0105] (5) Concentrate, crystallize, perform first centrifugation, first drying, re-dissolve, re-crystallize, perform second centrifugation, and second drying on the aqueous succinic acid solution in sequence to obtain the biomass-derived succinic acid;

[0106] The temperature of the concentration is 60 - 80°C, the system pressure is 10 - 40 kPa, and the concentration multiple is 2 - 10 times;

[0107] The temperatures of the crystallization and re-crystallization are each independently 10 - 30°C, and the system pressures are each independently 60 - 80 kPa;

[0108] The temperature of the re-dissolution is 40 - 80°C, and the system pressure is 5 - 30 kPa;

[0109] The temperatures of the first drying and the second drying are each independently 75 - 85°C.

[0110] It should be noted that the preparation method of the succinic acid derived from biomass is not limited to the preparation method provided in the second aspect of the present invention. Those skilled in the art can also select other methods or routes to obtain the succinic acid derived from biomass proposed in the present invention. Exemplarily, the fermentation broth can be purified by a combination of methods such as ultrafiltration, multiple ion exchange, decolorization, electrodialysis, and multiple recrystallization to obtain succinic acid derived from biomass with a low impurity content.

[0111] In a third aspect, the present invention provides an application of the succinic acid derived from biomass as described in the first aspect in the preparation of polyesters.

[0112] Preferably, the polyester includes poly(butylene succinate) (PBS).

[0113] Preferably, the preparation method of the poly(butylene succinate) includes: subjecting the succinic acid derived from biomass provided in the first aspect to an esterification reaction with 1,4 - butanediol to obtain an esterified product; and subjecting the esterified product to a polycondensation reaction to obtain the poly(butylene succinate).

[0114] Preferably, the molar ratio of the succinic acid derived from biomass to 1,4 - butanediol is 1:(1.2 - 1.6), and can be, for example, 1:1.22, 1:1.25, 1:1.28, 1:1.3, 1:1.32, 1:1.35, 1:1.38, 1:1.4, 1:1.42, 1:1.45, 1:1.48, 1:1.5, 1:1.52, 1:1.55, or 1:1.58, etc.

[0115] Preferably, the temperature of the esterification reaction is 150 - 170°C, and can be, for example, 152°C, 154°C, 155°C, 156°C, 158°C, 170°C, 172°C, 174°C, 175°C, 176°C, or 178°C, etc.

[0116] Preferably, the time of the esterification reaction is 2 - 4 h, and can be, for example, 2.2 h, 2.5 h, 2.8 h, 3 h, 3.2 h, 3.5 h, or 3.8 h, etc.

[0117] Preferably, the polycondensation reaction is carried out in the presence of a catalyst and a branching agent.

[0118] Preferably, the catalyst includes a titanate catalyst, and more preferably includes any one or a combination of at least two of tetramethyl titanate, tetraethyl titanate, tetra - isopropyl titanate, tetra - n - butyl titanate, and tetra - isooctyl titanate.

[0119] Preferably, based on the total mass of succinic acid and 1,4-butanediol from the biomass source being 100%, the dosage of the catalyst is such that the mass of Ti element is 50 - 200 ppm, for example, it can be 60 ppm, 80 ppm, 100 ppm, 120 ppm, 140 ppm, 150 ppm, 160 ppm or 180 ppm, etc.

[0120] Preferably, the branching agent includes polyols (other polyols different from 1,4-butanediol), and more preferably includes any one or a combination of at least two of glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol, 2,2-dimethylolpropionic acid.

[0121] Preferably, based on the total mass of succinic acid and 1,4-butanediol from the biomass source being 100%, the dosage of the branching agent is such that the mass of hydroxyl group is 200 - 1000 ppm, for example, it can be 250 ppm, 300 ppm, 350 ppm, 400 ppm, 450 ppm, 500 ppm, 550 ppm, 600 ppm, 650 ppm, 700 ppm, 750 ppm, 800 ppm, 850 ppm, 900 ppm or 950 ppm, etc.

[0122] Preferably, the polycondensation reaction is carried out in the presence of a heat stabilizer.

[0123] Preferably, the heat stabilizer includes phosphate ester compounds, and more preferably includes any one or a combination of at least two of trimethyl phosphate, triethyl phosphate, isopropyl phosphate, n-butyl phosphate, isooctyl phosphate, triphenyl phosphate.

[0124] Preferably, based on the total mass of succinic acid and 1,4-butanediol from the biomass source being 100%, the dosage of the heat stabilizer is such that the mass of P element is 5 - 100 ppm, for example, it can be 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm or 90 ppm, etc.

[0125] Preferably, the polycondensation reaction includes a prepolymerization reaction and a final polymerization reaction carried out in sequence.

[0126] Preferably, the temperature of the prepolymerization reaction is 180 - 240 °C, for example, it can be 185 °C, 190 °C, 195 °C, 200 °C, 205 °C, 210 °C, 215 °C, 220 °C, 225 °C, 230 °C or 235 °C, etc.

[0127] Preferably, the pressure of the prepolymerization reaction is 1 - 5 kPa, for example, it can be 1.5 kPa, 2 kPa, 2.5 kPa, 3 kPa, 3.5 kPa, 4 kPa or 4.5 kPa, etc.

[0128] Preferably, the time of the prepolymerization reaction is 1 - 3 h, for example, it can be 1.2 h, 1.5 h, 1.8 h, 2 h, 2.2 h, 2.5 h, 2.8 h, etc.

[0129] Preferably, the temperature of the final polymerization reaction is 220 - 260 °C, for example, it can be 222 °C, 225 °C, 228 °C, 230 °C, 232 °C, 235 °C, 238 °C, 240 °C, 242 °C, 245 °C, 248 °C, 250 °C, 252 °C, 255 °C, 258 °C, etc.

[0130] Preferably, the pressure of the final polymerization reaction is 20 - 100 Pa, for example, it can be 25 Pa, 30 Pa, 35 Pa, 40 Pa, 45 Pa, 50 Pa, 55 Pa, 60 Pa, 65 Pa, 70 Pa, 75 Pa, 80 Pa, 85 Pa, 90 Pa, 95 Pa, etc.

[0131] Preferably, the time of the final polymerization reaction is 2 - 6 h, for example, it can be 2.2 h, 2.5 h, 2.8 h, 3 h, 3.2 h, 3.5 h, 3.8 h, 4 h, 4.2 h, 4.5 h, 4.8 h, 5 h, 5.2 h, 5.5 h, 5.8 h, etc.

[0132] Preferably, after the final polymerization reaction is completed, it further includes the step of extrusion granulation.

[0133] Compared with the prior art, the present invention has the following beneficial effects:

[0134] (1) The succinic acid from biomass sources provided by the present invention contains specific contents of iron ions, chloride ions, sulfate ions, and phosphate ions. The succinic acid has high purity and low inorganic salt content, and the inorganic salt content is significantly lower than the index requirements for first-class succinic acid in GB / T 34686 - 2017. The succinic acid from biomass sources is used to prepare PBS resin, which can endow the PBS resin with better anti-aging performance and higher mechanical properties.

[0135] (2) The succinic acid from biomass sources provided by the present invention is prepared from renewable biomass resources. A fermentation broth containing succinic acid is obtained through fermentation, and a combined purification process including ultrafiltration, multi-stage forward cross-flow extraction, and multi-stage reverse cross-flow extraction is designed to effectively reduce the content of impurities such as inorganic salts in the fermentation broth. Moreover, steps such as the calcium salt method, ammonium salt method, ion exchange, decolorization, and electrodialysis used in traditional purification methods are omitted, avoiding the introduction of impurities, and obtaining high-quality succinic acid from biomass sources. Detailed implementation manners

[0136] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0137] As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device containing the listed elements is not necessarily limited to those elements, but may also include other elements not expressly listed or elements inherent to such composition, step, method, article or device.

[0138] In the present invention, the features defined as "first", "second" may explicitly or implicitly include one or more of such features, which are used to distinguish and describe features, without order or importance. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0139] In the following specific embodiments of the present invention, each component for preparing the culture medium and various reagents for the purification treatment of the filtrate are commercially available chemicals; the specific information of some materials is as follows:

[0140] (1) Succinic acid-producing strains

[0141] Commercially available Escherichia coli and Actinobacillus succinogenes.

[0142] (2) Culture medium

[0143] Seed culture medium A1, the components are as follows: peptone 12 g / L, yeast extract 3 g / L, NaCl 5 g / L, and the solvent is water.

[0144] Seed culture medium A2, the components are as follows: glucose 10 g / L, yeast extract 10 g / L, corn steep liquor 5 g / L, NaHCO3 5 g / L, NaH2PO4 10 g / L, K2HPO4 2 g / L, and the solvent is water.

[0145] Fermentation medium B1, with the following components: glucose 25 g / L, citric acid 0.5 g / L, Na2HPO4·12H2O 5 g / L, KH2PO4 10 g / L, NH4Cl 0.3 g / L, (NH4)2SO4 0.5 g / L, MgSO4·7H2O 1 g / L, CaCl2·2H2O 5 mg / L, ZnSO4·7H2O 0.5 mg / L, CuCl2·2H2O 0.2 mg / L, MnSO4·H2O 2 mg / L, CoCl2·6H2O 2 mg / L, H3BO3 0.1 mg / L, Al2(SO4)3 2 mg / L, Na2MoO4·2H2O 0.5 mg / L, ferric citrate 20 mg / L, vitamin B1 20 mg / L, biotin 2 mg / L, magnesium carbonate basic 20 g / L, and the solvent is water.

[0146] Fermentation medium B2, with the following components: glucose 80 g / L, peptone 10 g / L, potassium dihydrogen phosphate 2 g / L, sodium bicarbonate 2 g / L, calcium chloride 0.2 g / L, magnesium chloride 0.2 g / L, and the solvent is water.

[0147] In the following specific embodiments of the present invention, the phosphate ester complexing agents, alcohol solvents, etc. involved are all commercially available chemicals.

[0148] In the following specific embodiments of the present invention, the test method for succinic acid derived from biomass is as follows:

[0149] (1) The content (purity), chloride ions, SO4 2- , heavy metals (calculated as Pb), and the content of ignition residue are tested and obtained by the method in Standard GB / T 34686-2017.

[0150] (2) The mass content of iron ions is tested and obtained by the method in Standard GB / T 9739-2006.

[0151] (3) The content of phosphate ions is tested and obtained by the method in GB / T 9727-2007.

[0152] Example 1

[0153] A succinic acid derived from biomass and its preparation method, the preparation method comprising the following steps:

[0154] (1) Seed liquid of Escherichia coli:

[0155] Inoculate a single colony of Escherichia coli strain on the plate into seed medium A1, and culture it in an incubator at 36 °C for 10 h to obtain the seed liquid;

[0156] (2) Preparation of fermentation broth:

[0157] Add the fermentation medium B1 into a 5 L fermenter, and inoculate the seed liquid obtained in step (1) into the fermentation medium B1 at an inoculation amount of 5% for fermentation. First, perform aerobic fermentation until the cell growth reaches the stationary phase. The temperature of the aerobic fermentation is 35°C, the dissolved oxygen content is 30%, the rotation speed is 300 r / min, and the time is 8 h. Then, perform anaerobic fermentation at a temperature of 37°C, a dissolved oxygen content of 0, and a rotation speed of 265 r / min. During the fermentation process, monitor the pH value and control the pH value at 6.2 by introducing sodium hydroxide solution (mass concentration: 5%). After 42 h of anaerobic fermentation, obtain the fermentation broth.

[0158] (3) Use a 30 nm pore size ultrafiltration membrane to ultrafilter the fermentation broth obtained in step (2). The temperature of the ultrafiltration is 45°C, and the concentration multiple is 35 times to obtain the permeate.

[0159] (4) Perform multi-stage forward cross-flow extraction on the permeate with an extractant. The extractant is a mixture of diisooctyl phosphate and n-heptanol, and the volume ratio of diisooctyl phosphate to n-heptanol is 1:10. The volume ratio of the extractant to the permeate is 5:1. The number of stages of the multi-stage forward cross-flow extraction is 2, and the temperature is 60°C to obtain the succinic acid-loaded organic phase.

[0160] (5) Perform multi-stage reverse cross-flow extraction on the succinic acid-loaded organic phase obtained in step (4) with a stripping agent. The volume ratio of the succinic acid-loaded organic phase to the stripping agent is 1:4. The temperature of the multi-stage reverse cross-flow extraction is 50°C, and the number of stages is 5. The stripping agent for the first stage is water, and the stripping agents for the 2nd - 5th stages are sodium carbonate aqueous solutions with a mass concentration of 5% to obtain the succinic acid aqueous solution.

[0161] (6) Evaporate and concentrate the succinic acid aqueous solution obtained in step (5) at a temperature of 80°C, a system pressure of 40 kPa, and a concentration multiple of 3 times.

[0162] After concentration, perform cooling crystallization at 10°C and a system pressure of 80 kPa, then perform centrifugal separation and drying at 80°C to obtain the crude crystals.

[0163] Redissolve the crude crystals in water at 60°C and a system pressure of 13 kPa, perform recrystallization at 15°C and a system pressure of 75 kPa, then perform centrifugal separation and drying at 80°C to obtain succinic acid from biomass sources, and its component information is shown in Table 1.

[0164] Example 2

[0165] A succinic acid from biomass sources and its preparation method. The preparation method includes the following steps:

[0166] (1) Seed liquid of Actinobacillus succinogenes

[0167] Inoculate a single colony of Actinobacillus succinogenes on the flat plate into the seed medium A2, and culture it in an incubator at 36 °C for 16 h to obtain a seed solution;

[0168] (2) Preparation of the fermentation broth:

[0169] Add the fermentation medium B2 into a 5 L fermenter, inoculate the seed solution obtained in step (1) into the fermentation medium B2 at an inoculation amount of 8% for fermentation. First, perform aerobic fermentation until the cell growth reaches the stationary phase. The temperature of the aerobic fermentation is 33 °C, the dissolved oxygen content is 35%, the rotation speed is 350 r / min, and the time is 12 h; then perform anaerobic fermentation at a temperature of 35 °C, a dissolved oxygen content of 0.05%, and a rotation speed of 250 r / min; monitor the pH value during the fermentation process, and control the pH value at 6.8 by introducing a sodium carbonate solution (mass concentration: 8%); after 36 h of anaerobic fermentation, obtain the fermentation broth;

[0170] (3) Ultrafilter the fermentation broth obtained in step (2) using a 50 nm pore size ultrafiltration membrane. The temperature of the ultrafiltration is 50 °C, and the concentration multiple is 25 times to obtain the permeate;

[0171] (4) Perform multi-stage forward cross-flow extraction on the permeate using an extractant. The extractant is a mixture of dimethylheptyl methylphosphonate and isooctanol, and the volume ratio of the two is 1:1; the volume ratio of the extractant to the permeate is 4:1; the number of stages of the multi-stage forward cross-flow extraction is 3, and the temperature is 40 °C to obtain the succinic acid-loaded organic phase;

[0172] (5) Perform multi-stage reverse cross-flow extraction on the succinic acid-loaded organic phase obtained in step (4) using a stripping agent. The volume ratio of the succinic acid-loaded organic phase to the stripping agent is 1:5. The temperature of the multi-stage reverse cross-flow extraction is 70 °C, and the number of stages is 4. The stripping agent for the first stage is water, and the stripping agents for the second to fourth stages are sodium carbonate aqueous solutions with a mass concentration of 8% to obtain a succinic acid aqueous solution;

[0173] (6) Evaporate and concentrate the succinic acid aqueous solution obtained in step (5) at a temperature of 70 °C, a system pressure of 25 kPa, and a concentration multiple of 5 times;

[0174] After concentration, perform cooling crystallization at 20 °C and a system pressure of 70 kPa, then perform centrifugal separation and drying at 85 °C to obtain crude crystals;

[0175] Redissolve the crude crystals in water at 75 °C and a system pressure of 25 kPa, perform recrystallization at 25 °C and a system pressure of 65 kPa, then perform centrifugal separation and drying at 85 °C to obtain succinic acid from biomass sources, and its component information is shown in Table 1.

[0176] Examples 3-6, Comparative Examples 1-4

[0177] Succinic acid derived from biomass and its preparation method. The specific parameters of the preparation method are shown in Table 1 and Table 2. Items not listed in Table 1 and Table 2 are the same as those in Example 1; the component information of the succinic acid derived from biomass is shown in Table 1 and Table 2.

[0178] Table 1

[0179]

[0180]

[0181]

[0182] Table 2

[0183]

[0184]

[0185]

[0186] The technical indicators of industrial succinic acid in GB / T 34686-2017 are as follows:

[0187]

[0188]

[0189] According to the data in Table 1 and Table 2, in the succinic acid derived from biomass provided by the present invention, the purity of succinic acid is ≥99.79%, the mass content of iron ions is controlled at 1-4.2 ppm, further preferably 1-2 ppm, the mass content of chloride ions is 6-14 ppm, the mass content of sulfate ions is 34-88 ppm, further preferably 75-88 ppm, the mass content of phosphate ions is 89-172 ppm, further preferably 128-172 ppm, the water content is ≤610 ppm, the heavy metal content is ≤0.2 ppm, and the ignition residue content is ≤100 ppm, making the inorganic salt content significantly lower than the index requirements of first-class succinic acid in GB / T 34686-2017. The succinic acid derived from biomass is used to prepare PBS resin, which can endow the PBS resin with better anti-aging performance and higher mechanical properties.

[0190] Furthermore, the present invention preferably adopts a fermentation mode combining aerobic fermentation and anaerobic fermentation, and designs a combined purification process including ultrafiltration, multi-stage forward cross-flow extraction, multi-stage reverse cross-flow extraction, concentration and crystallization. Combined with specific extractants and stripping agents, succinic acid derived from biomass with high purity and low inorganic salt content is obtained, eliminating steps such as calcium salt method, ammonium salt method, ion exchange, decolorization and electrodialysis used in traditional purification methods and avoiding the introduction of impurities.

[0191] The following are exemplary application examples of using the succinic acid derived from biomass of the present invention to prepare polybutylene succinate (PBS). In the following specific embodiments of the present invention, reagents whose preparation methods are not specified are all conventional commercially available chemicals.

[0192] Application Examples 1-9

[0193] The preparation method of PBS includes the following steps:

[0194] (1) Mix succinic acid derived from biomass (from Examples 1-9 respectively) with 1,4-butanediol (purity 99.7%, purchased from Liaoning Jinfafa Biomaterials Co., Ltd.) at a molar ratio of 1:1.2, and carry out an esterification reaction at 150 °C for 3 h to obtain an esterified product;

[0195] (2) Place the esterified product obtained in step (1), a catalyst (tetrabutyl titanate), a branching agent (glycerol) and a heat stabilizer (triethyl phosphate) in a reaction kettle. Based on the total mass of succinic acid and 1,4-butanediol being 100%, the amount of the catalyst is such that the mass of Ti element is 100 ppm, the amount of the branching agent is such that the mass of its hydroxyl group is 500 ppm, and the amount of the heat stabilizer is such that the mass of P element in it is 20 ppm; First, raise the temperature to 220 °C and carry out a prepolymerization reaction under the condition of 2 kPa for 2 h, and then raise the temperature to 240 °C and control the pressure at 80 Pa and continue the reaction for 2 h. The obtained polymerization product is extruded and pelletized to obtain the PBS.

[0196] Control Examples 1-4

[0197] The preparation method of PBS is only different from that of Application Example 1 in that the succinic acid of Comparative Examples 1-4 is used to replace the succinic acid from Example 1 of the present invention in Application Example 1, and the types, amounts and process steps of other materials are the same as those in Application Example 1 to obtain PBS.

[0198] The PBS prepared above was injection-molded into splines according to the method in Standard ISO 527-2-2012, and the tensile strength and elongation at break (before aging) were tested; then the splines were aged in an aging test chamber at 60 °C and 60% humidity for 10 days, and then the tensile strength and elongation at break of the aged PBS were tested according to the method in Standard ISO 527-2-2012, and the test condition was 50 mm / min; Tensile strength retention rate = 100% × tensile strength after aging / tensile strength before aging, Elongation at break retention rate = 100% × elongation at break after aging / elongation at break before aging, and the obtained data are shown in Table 3:

[0199] Table 3

[0200] Source of succinic acid Tensile strength retention rate (%) Elongation at break retention rate (%) Application Example 1 Example 1 76.2 54.4 Application Example 2 Example 2 74.6 52.2 Application Example 3 Example 3 78.5 55.5 Application Example 4 Example 4 75.0 53.8 Application Example 5 Example 5 74.4 54.4 Application Example 6 Example 6 75.9 55.1 Application Example 7 Example 7 72.2 50.2 Application Example 8 Example 8 71.5 50.5 Application Example 9 Example 9 73.0 51.9 Control Example 1 Comparative Example 1 70.2 46.5 Control Example 2 Comparative Example 2 69.5 45.5 Control Example 3 Comparative Example 3 68.1 44.4 Control Example 4 Comparative Example 4 70.8 48.0

[0201] According to the data in Table 3, it can be seen that the succinic acid of biomass origin provided by the present invention has lower impurity content and better performance indicators. When it is used to prepare PBS resin, the tensile strength retention rate of the PBS resin is ≥ 71.5%, further preferably ≥ 74.4%, the elongation at break retention rate is ≥ 50%, further preferably ≥ 52.2%. The improvement of the tensile strength retention rate and the elongation at break retention rate shows more excellent aging resistance and mechanical properties.

[0202] The content of inorganic ions in the succinic acid of Comparative Examples 1-4 is high, resulting in obvious attenuation of the tensile strength and elongation at break of the PBS resin prepared therefrom after aging, and insufficient aging resistance.

[0203] The applicant declares that the present invention uses the above-mentioned examples to illustrate the succinic acid of biomass origin and its preparation method and application of the present invention, but the present invention is not limited to the above-mentioned examples, that is, it does not mean that the present invention must rely on the above-mentioned examples to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. Succinic acid derived from biomass, characterized in that, The succinic acid of biomass origin includes succinic acid, iron ions, chloride ions, sulfate ions, and phosphate ions; the mass content of iron ions in the succinic acid of biomass origin is 0.01 - 5 ppm, the mass content of chloride ions is 0.1 - 15 ppm, the mass content of sulfate ions is 0.1 - 100 ppm, and the mass content of phosphate ions is 0.1 - 200 ppm.

2. The succinic acid derived from biomass according to claim 1, wherein The mass percentage of succinic acid in the succinic acid of biomass origin is ≥ 99.7%, preferably ≥ 99.75%.

3. The succinic acid derived from biomass according to claim 1, characterized in that, The succinic acid of biomass origin further includes water and / or heavy metals; Preferably, the mass content of water in the succinic acid of biomass origin is 0.01 - 2000 ppm; Preferably, the mass content of heavy metals in the succinic acid of biomass origin is 0.01 - 10 ppm; Preferably, the content of ignition residue of the succinic acid of biomass origin is 1 - 200 ppm.

4. A method for preparing succinic acid from biomass as described in any one of claims 1 - 3, characterized in that, The preparation method includes the following steps: Inoculate the seed liquid of succinic acid-producing strain into a culture medium for fermentation to obtain a fermentation broth; Ultrafilter the fermentation broth to obtain a permeate; Perform multi-stage forward cross-flow extraction on the permeate with an extractant to obtain a succinic acid-loaded organic phase; Perform multi-stage reverse cross-flow extraction on the succinic acid-loaded organic phase with a stripping agent to obtain an aqueous succinic acid solution; Concentrate and crystallize the aqueous succinic acid solution to obtain the succinic acid of biomass origin.

5. The preparation method according to claim 4, characterized in that, The succinic acid-producing strain includes Escherichia coli, Actinobacillus succinogenes, or Anaerobiospirillum; Preferably, the inoculation amount of the seed liquid is 1 - 10%; Preferably, the pH value of the fermentation is 6.0 - 7.5; Preferably, the stirring speed of the fermentation is 100 - 600 r / min; Preferably, the temperature of the fermentation is 30 - 40 °C, and the time is 20 - 70 h; Preferably, the fermentation includes aerobic fermentation and anaerobic fermentation carried out in sequence; Preferably, the temperature of the aerobic fermentation is 33 - 40 °C, the stirring speed is 300 - 500 r / min, and the time is 6 - 12 h; Preferably, the temperature of the anaerobic fermentation is 30 - 40 °C, the stirring speed is 200 - 300 r / min, and the time is 30 - 50 h.

6. The preparation method according to claim 4, characterized in that, The pore size of the ultrafiltration membrane used for ultrafiltration is 20 - 80 nm; Preferably, the temperature of the ultrafiltration is 40 - 60 °C; Preferably, the concentration multiple of the ultrafiltration is 10 - 40 times.

7. The preparation method according to claim 4, characterized in that, The extractant includes a combination of a phosphoric acid ester complexing agent and a cosolvent; Preferably, the phosphoric acid ester complexing agent has a structure shown in Formula I: Wherein, R1 is selected from any one of C1 - C10 straight-chain or branched-chain alkyl groups; R2 is selected from any one of H, C1 - C10 straight-chain or branched-chain alkyl groups; R3 is selected from any one of C1 - C10 straight-chain or branched-chain alkyl groups, hydroxyl groups, and C1 - C10 alkoxy groups; Preferably, the phosphoric acid ester complexing agent includes any one or a combination of at least two of diisooctyl phosphate, dimethylheptyl methylphosphonate, and mono(2-ethylhexyl) 2-ethylhexyl phosphate; Preferably, the cosolvent includes a C6-C12 alcohol solvent, more preferably any one or a combination of at least two of n-heptanol, isooctanol, n-nonanol, and n-decanol; Preferably, the volume ratio of the phosphate complexing agent to the cosolvent is 1:(0.1-10); Preferably, the volume ratio of the extractant to the permeate is (2-7):1, more preferably (3-5):1; Preferably, the number of stages of the multi-stage forward cross-flow extraction is 2-5 stages, more preferably 2-3 stages; Preferably, the temperature of the multi-stage forward cross-flow extraction is 20-60°C.

8. The preparation method according to claim 4, characterized in that, The number of stages of the multi-stage counter-current cross-flow extraction is 2-6 stages, preferably 3-5 stages; Preferably, the stripping agent for the first-stage counter-current cross-flow extraction is water, and the stripping agents for the 2-nth stage counter-current cross-flow extractions are alkaline salt aqueous solutions; n represents an integer from 3 to 5; Preferably, the alkaline salt includes any one or a combination of at least two of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate; Preferably, the mass percentage content of the alkaline salt in the alkaline salt aqueous solution is 5%-12%; Preferably, the volume ratio of the stripping agent to the succinic acid-loaded organic phase is (1.5-6):1, more preferably (3-5):1; Preferably, the temperature of the multi-stage counter-current cross-flow extraction is 40-80°C.

9. The preparation method according to claim 4, characterized in that The temperature of the concentration is 60-80°C, and the system pressure is 10-40 kPa; Preferably, the concentration multiple is 2-10 times; Preferably, the temperature of the crystallization is 10-30°C, and the system pressure is 60-80 kPa; Preferably, after the crystallization, there are also steps of redissolution and recrystallization; Preferably, the solvent used for the redissolution includes water; Preferably, the temperature of the recrystallization is 10-30°C, and the system pressure is 60-80 kPa.

10. Use of succinic acid derived from biomass according to any one of claims 1-3 in the preparation of a polyester; Preferably, the polyester includes polybutylene succinate.

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