Method for producing long-chain dicarboxylic acid and product

Abstract

The invention provides a method for producing long-chain dicarboxylic acid and a long-chain dicarboxylic acid product. The method comprises the following steps: inoculating a seed solution of a fermentation strain into a fermentation tank, wherein a fermentation substrate comprises any one or more of fatty acid and derivatives thereof, and alkane; according to the method, green raw materials such as fatty acid and derivatives thereof, plant-based alkane and the like are adopted as substrates to partially or completely replace fossil energy such as petroleum alkane and the like, the product is green long-chain binary acid, and the bio-based content can be regulated and controlled. And the fermentation method provided by the invention can still maintain relatively high yield and conversion rate.

Description

Technical Field

[0001] The invention belongs to the technical field of fermentation, and in particular relates to a method for producing long-chain dibasic acid and a long-chain dibasic acid product. Background Art

[0002] Long-chain dibasic acids are widely used in many fields due to the uniqueness of their molecular structure and reactivity. They can be used as raw materials to synthesize special nylon (polyamide), high-grade fragrances, high-grade hot-melt adhesives, cold-resistant plasticizers, high-grade lubricants, high-grade rust inhibitors, high-grade paints and coatings, etc.

[0003] Long-chain dibasic acids have important and extensive industrial uses, but they do not exist alone in nature, and their sources vary depending on the chain length. The synthesis methods include chemical synthesis and biological fermentation. The chemical synthesis method has the characteristics of complex process, harsh conditions, many steps, low yield, low purity, high cost, and pollution. The biological method usually uses the corresponding long-chain alkanes and their derivatives as substrates and uses tropical yeast to ferment and produce long-chain dibasic acids. Compared with the chemical synthesis method, it has a simple production process, mild conditions, specific reaction, high yield, low energy consumption, and simple extraction and purification process.

[0004] my country has been engaged in the research of long-chain dibasic acids for more than 40 years, mainly using petroleum-based alkanes as substrates. However, new plant-based resources such as fatty acids, fatty acid salts, and fatty acid esters can replace fossil raw materials such as petroleum-based alkanes, which is of great significance to the sustainable development of industrial processes. Summary of the invention

[0005] The present invention provides a method and product for producing long-chain dibasic acids. The method can use green and environmentally friendly fermentation substrates such as fatty acids and their derivatives such as fatty acid salts, fatty acid esters, etc. and plant-based alkanes to partially or completely replace fossil energy such as petroleum-based alkanes, and can maintain a high yield and conversion rate.

[0006] To achieve the above objectives, the first aspect of the present invention is to provide a method for producing long-chain dibasic acids, the method comprising: introducing the seed liquid of the fermentation strain into a fermentation tank, and the fermentation substrate comprises any one or more of fatty acids and their derivatives and alkanes.

[0007] In one embodiment, the chemical formula of the long-chain dibasic acid is HOOC(CH2)nCOOH, wherein n≥8, including any one of decanedioic acid, undecanedicarboxylic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedicarboxylic acid, hexadecanedioic acid, heptadecanedioic acid and octadecanedicarboxylic acid.

[0008] In one embodiment, the fatty acid derivatives include fatty acid esters and fatty acid salts.

[0009] In one embodiment, the fermentation substrate preferably includes at least one of fatty acid, fatty acid ester and fatty acid salt.

[0010] In one embodiment, the fermentation substrate includes alkanes and at least one of fatty acids, fatty acid esters, and fatty acid salts.

[0011] In one embodiment, the alkane is a petroleum-based alkane and / or a bio-based alkane.

[0012] In one embodiment, the fatty acid is a straight-chain monocarboxylic acid having 10 or more carbon atoms, and further a straight-chain monocarboxylic acid having 10 to 18 carbon atoms, including any one of decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid and octadecanoic acid.

[0013] In one embodiment, the fatty acid salt comprises any one of sodium salt, potassium salt, ammonium salt and calcium salt of fatty acid. The fatty acid has the same definition as above. Fatty acids mainly come from seeds of oil-rich tropical crops such as palm trees and coconut trees. This new type of renewable resource can replace fossil raw materials such as petroleum alkanes, which is of great significance to the sustainable development of industrial processes.

[0014] In one embodiment, the fatty acid ester includes any one of decanoate, undecanoate, laurate, tridecanoate, myristate, pentadecanoate, palmitate, heptadecanoate and octadecanoate. For example, methyl laurate, ethyl laurate, butyl laurate, methyl myristate, ethyl myristate, butyl myristate, methyl palmitate, ethyl palmitate, butyl palmitate, etc. Because fatty acid ester is liquid at room temperature, it has good dispersion effect and has characteristics similar to alkanes, and can replace the substrate alkanes used at this stage. Fatty acid ester mainly comes from the seeds of tropical crops rich in oil such as palm trees and coconut trees. This new renewable resource can replace fossil raw materials such as petroleum alkanes, which is of great significance to the sustainable development of industrial processes. Fatty acids have the same limitations as above.

[0015] In one embodiment, the alkane includes a straight-chain alkane having 10 or more carbon atoms, and further a straight-chain alkane having 10 to 18 carbon atoms, including any one of decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane and n-octadecane.

[0016] In one embodiment, the fermentation substrates are fatty acids and alkanes, and the mass ratio of fatty acids to alkanes is (0.1-25):15, further (1-20):15.

[0017] In one embodiment, the fermentation strain comprises Candida viswanathii, Candida albicans, Candida tropicalis, Candida sake or Yarrowia lipolytica.

[0018] In one embodiment, the seed solution is introduced into the fermentation tank at an inoculation rate of 10% to 50%. The percentage represents volume percentage (v / v).

[0019] The fermentation tank contains a fermentation medium, which includes a nitrogen source, a carbon source, a growth factor, an inorganic salt, and may also contain additives such as a defoaming agent.

[0020] In one embodiment, the fermentation medium includes the following components: 0% to 1.0% corn steep liquor, 2.0% to 6.0% glucose, 0% to 0.8% yeast extract, 0.4% to 1.0% potassium dihydrogen phosphate, 0.2% to 0.6% magnesium sulfate, 0.1% to 1% ammonium sulfate, and 0.2% to 0.8% potassium nitrate.

[0021] In one embodiment, the seed liquid of the fermentation strain is inoculated into a fermentation tank filled with fermentation medium.

[0022] In one embodiment, the optical density value OD of the seed solution of the fermentation strain when diluted 30 times is 620 It is 0.5~1.0.

[0023] In one embodiment, the method for preparing the seed solution comprises the following steps: activating the fermentation strain in a shake flask, and waiting for the optical density value OD of the shake flask seeds to be 30 times diluted. 620 When the optical density of the seed solution is 0.5 to 1.0, the seed is placed in a seed tank filled with a seed culture medium for seed culture until the optical density of the seed solution is OD 620 Reach 0.5~1.0.

[0024] The conditions for activation culture include: temperature of 27-35°C, shaking speed of 150-250 rpm, and time of 38-42 hours.

[0025] The conditions for seed culture include: temperature of 27-35°C, air volume of 0.2-0.8vvm, pressure of 0.05-0.20MPa, and dissolved oxygen of 5-50%.

[0026] The seed culture medium includes nitrogen source, carbon source, inorganic salts, growth factors and defoaming agents, etc. The carbon sources of the seed culture medium include glucose, maltose, sucrose, etc., the nitrogen sources include corn syrup, urea, yeast extract, potassium nitrate, ammonium sulfate, etc., the inorganic salts include potassium dihydrogen phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, potassium nitrate, sodium chloride, ferrous sulfate, magnesium sulfate, etc., and the nutritional factors include vitamin B1, vitamin B2, vitamin B5, biotin, etc.

[0027] In one embodiment, the seed culture medium includes the following components: 0.2% to 0.8% corn steep liquor, 0.5% to 3.5% sucrose, 0.2% to 0.8% urea, 0.1% to 1% yeast extract, 0.2% to 1.0% potassium dihydrogen phosphate, and 0.02% to 0.10% defoaming agent.

[0028] In one embodiment, the fermentation substrate is added before, simultaneously with or after the seed solution of the fermentation strain is introduced into the fermentation tank.

[0029] The fermentation substrate can be added or supplemented by one-time addition, batch addition or continuous flow addition.

[0030] In one embodiment, the seed solution of the fermentation strain is first introduced into the fermentation tank. 620 When diluted 30 times to 0.5-1.0, the fermentation substrate is added to start fermentation.

[0031] In one embodiment, during the fermentation process, the fermentation substrate is added to the fermentation system to maintain the viscosity of the fermentation system at an appropriate level, so that the strain maintains a high activity and acid production capacity.

[0032] In one embodiment, within T hours after the start of fermentation, the numerical relationship between the viscosity η of the fermentation system and the fermentation time t satisfies: η=a*e bt +c, wherein 135≤T≤165, 1.05≤a≤5.8, 0.02≤b≤0.045, 0≤c≤5.5, the unit of the viscosity η is mPa·s, and the unit of the fermentation time t is h. e is a natural constant, an infinite non-repeating decimal, and its value is approximately 2.718281828459045.

[0033] In one embodiment, the 145≤T≤155.

[0034] In one embodiment, 1.2≤a≤4.5.

[0035] In one embodiment, the 0.02≤b≤0.04.

[0036] In one embodiment, the 0.2≤c≤3.

[0037] In one embodiment, the fermentation substrate is added to the fermentation system within T hours after the start of fermentation.

[0038] In one embodiment, after 135 to 165 hours of fermentation, the addition of fermentation substrate is stopped.

[0039] In one embodiment, after 145 to 155 hours of fermentation, the addition of fermentation substrate is stopped.

[0040] After a certain period of fermentation, the addition of fermentation substrate is stopped, and the fermentation is continued using the remaining fermentation substrate in the fermentation system until the fermentation substrate is completely consumed or no long-chain dibasic acid is produced. The total fermentation time is calculated.

[0041] In one embodiment, during the fermentation process, the temperature is controlled at 27-33°C.

[0042] In one embodiment, during the fermentation process, the air volume is controlled to be 0.2-0.8 vvm, and / or the pressure is 0.05-0.20 MPa, and / or the pH value is 4.5-6.5, further 6.0-6.5, and / or the dissolved oxygen is 5%-50%, further 25%-50%.

[0043] The fermentation broth produced by fermentation can be directly used as a product, or the long-chain dibasic acid in the fermentation broth can be extracted as a final product.

[0044] In one embodiment, the method includes: purifying the fermentation broth, and the purification treatment includes: acidifying the fermentation broth, separating the solid, dissolving the solid in an organic solvent, crystallizing and separating the solid and liquid, washing and drying the separated solid to obtain a long-chain dibasic acid product.

[0045] In some embodiments, the pH of the acidification is 2 to 5, preferably 3.5 to 4.5. The long-chain dibasic acid is crystallized by acidification.

[0046] In one embodiment, the separation method comprises at least one of filtration or centrifugation.

[0047] In one embodiment, the mass ratio of the solid matter to the organic solvent is 1:(3-6).

[0048] In one embodiment, the organic solvent includes one or more of an acid, an alcohol, an ester and a ketone; wherein the alcohol includes one or more of methanol, ethanol, n-butanol and isopropanol, the acid includes acetic acid, the ketone includes acetone, and the ester includes at least one of ethyl acetate and butyl acetate.

[0049] In one embodiment, a decolorization treatment is performed after dissolving in an organic solvent and before crystallization. The decolorization method is preferably activated carbon decolorization, the amount of activated carbon added is no more than 4% of the clear solution, the decolorization temperature is 90-110°C, and the decolorization time is 30-190 minutes.

[0050] In one embodiment, the crystallization is cooling crystallization, and the terminal temperature of the cooling crystallization is 20-40°C.

[0051] The second aspect of the present invention is to provide a long-chain dibasic acid product with a purity of 98% or more, and further 99% or more.

[0052] The biobased content of the long-chain dibasic acid product can be adjusted according to different fermentation substrates, and can be 1% to 100%, further 5% to 100%, further 5% to 99%, further 5% to 80%, further 5% to 50%, for example 95%, 80%, 70%, 50%, 45%, 35%, 30%, 25%, 15%, 10%.

[0053] The present invention uses green raw materials such as fatty acids, fatty acid salts, fatty acid esters, plant-based alkanes, etc. as substrates to partially or completely replace fossil energy such as petroleum alkanes, and the target product long-chain dibasic acid can still maintain a relatively high yield and conversion rate. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] In the following examples, the content of dodecanedioic acid in the fermentation broth was determined by gas chromatography. Purity test of long-chain dibasic acid products: gas chromatography. Biobased content test: American Society for Testing and Materials standard ASTM-D6866 method.

[0056] The percentages used to characterize the content of components in the culture medium of the present invention are all based on the general conventions in the fermentation field, and the percentage represents the mass volume ratio (w / v), that is, % represents g / 100 mL.

[0057] The strain used in the embodiment: Candida viswanathii CAES2113, which has been disclosed in patent CN111748480A, was biologically deposited on February 24, 2020, and the depository unit is China Center for Type Culture Collection (address: Wuhan University, Wuhan, China), the deposit number is CCTCC M 2020048, and the classification name is Candida viswanathii.

[0058] The n-dodecane in Examples 1 to 3 is derived from petroleum, i.e., a petroleum-based alkane, with a purity of 99.92%. The n-dodecane in Example 4 is obtained by processing vegetable oils and fats, and is a bio-based alkane with a purity of 99.91%.

[0059] The viscosity η of the fermentation system is monitored by an online viscosity detector, and the amount of substrate added is controlled so that the numerical relationship between the viscosity η of the fermentation system and the fermentation time t satisfies η=a*e bt +c.

[0060] Example 1

[0061] (1) First, the pH value of 10°B malt juice was adjusted to about 5.4, and then 100 mL was placed in a conical flask and sterilized at 121°C for 20 min. Then, a seed of Candida visweiss (strain CAES2113) in a 2 mL glycerol tube stored in a -80°C refrigerator was inoculated and activated on a rotary shaker at 29°C and 220 rpm for 40 h. The OD of the bacteria was 0.1447 W / m. 620 When the value reaches 0.7 (30-fold dilution), the activation culture is completed.

[0062] (2) The shake flask seeds obtained in step (1) were inoculated into a seed tank containing a seed culture medium and cultured. The inoculation amount was 1.6% (v / v). The temperature during the culture process was controlled to be 29° C., the air volume was 0.33 vvm, the pressure was 0.11 MPa, and the dissolved oxygen was maintained at 15% until the OD of the obtained seed solution when diluted 30 times reached 0. 620 The value reaches 0.8.

[0063] The components of the seed culture medium are: 0.5% corn steep liquor (total nitrogen content is 2.5%), 2.3% sucrose, 0.3% urea, 0.5% yeast extract, 0.6% potassium dihydrogen phosphate, and 0.05% defoaming agent.

[0064] (3) The seed solution obtained in the above step (2) was inoculated into a fermentation tank filled with fermentation medium and fermented, with an inoculation amount of 15% (v / v), a fermentation temperature of 29° C., a pH value of 6.4, an air volume of 0.31 vvm, a pressure of 0.12 MPa during the fermentation process, and a dissolved oxygen of 42% during the fermentation process.

[0065] The components of the fermentation medium in the fermentation tank are: 0.9% corn syrup, 3.3% glucose, 0.4% yeast extract, 0.5% potassium dihydrogen phosphate, 0.2% magnesium sulfate, 0.4% ammonium sulfate, and 0.4% potassium nitrate.

[0066] After the seed solution was added to the fermentation tank, when the bacterial OD 620 When the value reaches 0.80 (diluted 30 times), the substrate is added to the fermenter for fermentation. From the beginning of fermentation to 150h of fermentation, the numerical relationship between the viscosity η (mpa·s) of the fermentation system and the fermentation time t (h) satisfies: η=2.95*e 0.026t +1.2. After 150h of fermentation, the addition of substrate was stopped. The fermentation substrates were lauric acid and n-dodecane, with a mass ratio of 12:18.

[0067] Example 2

[0068] Step (1): Same as Example 1.

[0069] Step (2): Same as Example 1.

[0070] Step (3): When the bacterial OD 620 When the value reaches 0.75 (diluted 30 times), the substrate is added to the fermentation tank for fermentation. From the beginning to 152h of fermentation, the numerical relationship between the viscosity η (mpa·s) of the fermentation system and the fermentation time t (h) satisfies: η=3.05*e 0.015t +0.91. After 152h of fermentation, the substrate addition was stopped. The fermentation substrate was lauric acid and n-dodecane, with a mass ratio of 10:20. The rest was the same as in Example 1.

[0071] Example 3

[0072] Step (1): Same as Example 1.

[0073] Step (2): Same as Example 1.

[0074] Step (3): When the bacterial OD 620 When the value reaches 0.84 (diluted 30 times), the substrate is added to the fermenter for fermentation. From the beginning to 154h of fermentation, the numerical relationship between the viscosity η (mpa·s) of the fermentation system and the fermentation time t (h) satisfies: η=4.02*e 0.032t +0.02. After 154h of fermentation, the substrate addition was stopped. The fermentation substrate was lauric acid and n-dodecane, with a mass ratio of 8:22. The rest was the same as in Example 1.

[0075] Example 4

[0076] Step (1): Same as Example 1.

[0077] Step (2): Same as Example 1.

[0078] Step (3): After the seed solution is added to the fermentation tank, when the bacterial OD 620 When the value reaches 0.82 (diluted 30 times), the substrate is added to the fermenter for fermentation. From the beginning to 155h of fermentation, the numerical relationship between the viscosity η (mpa·s) of the fermentation system and the fermentation time t (h) satisfies: η=2.98*e 0.022t +0.7. After 155h of fermentation, the addition of substrate was stopped. The rest was the same as in Example 1.

[0079] Comparative Example 1

[0080] Step (1): Same as Example 1.

[0081] Step (2): Same as Example 1.

[0082] Step (3): After the seed solution is added to the fermentation tank, when the bacterial OD 620 When the value reaches 0.80 (30 times dilution), the substrate is added to the fermentation tank for fermentation. From the beginning to 150h of fermentation, the numerical relationship between the viscosity η (mpa·s) of the fermentation system and the fermentation time t (h) satisfies: η=2.88*e 0.075t +0.9. After 150h of fermentation, the substrate addition was stopped. The fermentation substrate was lauric acid and n-dodecane, with a mass ratio of 15:15. The rest was the same as in Example 1.

[0083] The results of acid production, conversion rate and total fermentation time after fermentation are shown in Table 1.

[0084] Table 1

[0085] Acid production / (g / L) Conversion rate / % Total fermentation time / h Example 1 178.8 97.2 162 Example 2 180.5 97.8 160 Example 3 184.7 98.5 158 Example 4 173.6 96.4 163 Comparative Example 1 172.6 93.2 173

[0086] The fermentation broth obtained in the above examples and comparative examples was separated and purified as follows:

[0087] Sulfuric acid was added to the fermentation broth to adjust the pH to 3.7 for acidification and crystallization, and the solid was separated to obtain a crude product of dodecanedioic acid.

[0088] The crude product of dodecanedioic acid was placed in a decolorization tank, acetic acid was added, the mass ratio of crude dodecanedioic acid to acetic acid was controlled at 1:4, activated carbon was added, and the amount of activated carbon added was 1.6% (v / v) of the decolorization system. The above materials were heated to 95°C, decolorized for 50 minutes, and filtered through a plate and frame filter press to obtain a clear liquid. The clear liquid was cooled to 30°C, and after the crystals were precipitated, solid-liquid separation was performed by a centrifuge, and the obtained solid was washed and dried to obtain the dodecanedioic acid product. The purity and biobased content of the tested dodecanedioic acid product are shown in Table 2.

[0089] Table 2

[0090] purity / % Bio-based content / % Example 1 99.83 34.25 Example 2 99.80 28.37 Example 3 99.85 22.55 Example 4 99.72 99.57 Comparative Example 1 98.95 30.75

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing a long-chain dibasic acid, characterized in that: The method comprises: introducing the seed liquid of the fermentation strain into a fermentation tank, and the fermentation substrate comprises any one or more of fatty acids and derivatives thereof and alkanes.

2. The method according to claim 1, characterized in that The chemical formula of the long-chain dibasic acid is HOOC(CH2)nCOOH, wherein n≥8, including any one of sebacic acid, undecane dibasic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecane dibasic acid, hexadecanedioic acid, heptadecanedioic acid and octadecane dibasic acid; and / or, The fermentation substrate includes any one or a group of two or more of fatty acids, fatty acid esters, fatty acid salts, and alkanes.

3. The method according to claim 1, characterized in that Within T hours after the start of fermentation, the numerical relationship between the viscosity η of the fermentation system and the fermentation time t satisfies: η=a*e bt +c, wherein 135≤T≤165, 1.05≤a≤5.8, 0.02≤b≤0.045, 0≤c≤5.5, the unit of the viscosity η is mPa·s, and the unit of the fermentation time t is h.

4. The method according to claim 3, characterized in that 145≤T≤155。 5. The method according to claim 3, wherein the fermentation substrate is added to the fermentation system within T hours after the start of fermentation.

6. The method according to claim 1, characterized in that The optical density value OD of the seed solution when diluted 30 times 620 is 0.5 to 1.0; and / or, The seed liquid is introduced into a fermentation tank at an inoculation rate of 10% to 50%.

7. The method according to claim 1 or 3, characterized in that: During the fermentation process, the air volume is 0.2-0.8 vvm, and / or the pressure is 0.05-0.20 MPa, and / or the pH value is 4.5-6.5, and / or the dissolved oxygen is 5%-50%.

8. The method according to claim 1, characterized in that When the optical density of the fermentation strain in the fermentation system is OD 620 When diluted 30 times to 0.5-1.0, the fermentation substrate is added to start fermentation.

9. The method according to claim 1, 2 or 5, characterized in that: The fermentation substrates are fatty acids and alkanes, and the mass ratio of the fatty acids to the alkanes is (0.1-25):15, further (1-20):

15.

10. The method according to claim 1, characterized in that The fermentation medium comprises the following components: 0% to 1.0% corn steep liquor, 2.0% to 6.0% glucose, 0% to 0.8% yeast extract, 0.4% to 1.0% potassium dihydrogen phosphate, 0.1% to 0.6% magnesium sulfate, 0.1% to 1% ammonium sulfate and 0.2% to 0.8% potassium nitrate.

11. The method according to claim 1, 2 or 5, characterized in that: The alkane is a petroleum-based alkane and / or a bio-based alkane.

12. The method according to any one of claims 1 to 11, characterized in that The fermentation liquid is purified, and the purification process includes: acidifying the fermentation liquid, separating solids, dissolving the solids in an organic solvent, performing crystallization and solid-liquid separation, washing and drying the separated solids, and obtaining a long-chain dibasic acid product.

13. A long-chain dibasic acid product, characterized in that: The purity is 98% or more, further 99% or more; and / or, The biobased content may range from 1% to 100%, further from 5% to 100%, further from 5% to 99%, for example 95%, 80%, 70%, 50%, 45%, 35%, 30%, 25%, 15%, 10%.