A catalyst for non-enzymatic synthesis of phospholipid dha / dpa, preparation method and application thereof

Abstract

The application discloses a catalyst for non-enzyme synthesis of phospholipid DHA / DPA, a preparation method and application thereof. The catalyst for non-enzyme synthesis of phospholipid DHA / DPA is composed of a MnFe2O4 nano core, a SiO2 coating layer and a metal dopant M loaded on the surface; and the catalyst is subjected to calcination treatment to form Lewis acid sites on the surface of the SiO2. The catalyst for non-enzyme synthesis of phospholipid DHA / DPA has good magnetic response and regulated surface acidity, can realize efficient non-enzyme transesterification / acyl exchange reaction under a reverse microemulsion system, the catalyst is convenient for magnetic separation and recovery, has good circulation performance and is suitable for industrial amplification production.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials and biosynthesis, specifically relating to a catalyst for the enzyme-free synthesis of phospholipid DHA / DPA, its preparation method, and its application. Background Technology

[0002] DHA (docosahexaenoic acid) and DPA (docosapentaenoic acid), as omega-3 fatty acids with important physiological activities, exhibit superior phospholipid forms compared to their triglyceride forms in terms of nutrient absorption, stability, and bioavailability. Therefore, the preparation of phospholipid-based DHA / DPA has become an important direction for high-value utilization. Traditional enzymatic methods can achieve high selectivity, but their high cost, sensitive reaction systems, and the difficulty of enzymes tolerating non-aqueous environments limit large-scale application.

[0003] Solid acid catalysts have become a potential alternative to enzymatic methods due to their mild reaction conditions, strong environmental resistance, and recyclability. However, there is limited research on the MnFe2O4-SiO2 solid acid system in the current technology, especially regarding the effects of Zn and Al doping on the catalytic activity of phospholipid DHA / DPA synthesis, which still lacks systematic research.

[0004] Therefore, it is of great significance to develop a solid acid catalyst with stable structure and high catalytic efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a MnFe2O4-SiO2 solid acid catalyst with controllable surface acidity, good magnetic response and high stability, and to apply it to the non-enzymatic synthesis of phospholipid DHA / DPA to achieve a high DHA / DPA incorporation rate and reliable cycling performance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a catalyst for the enzyme-free synthesis of phospholipid DHA / DPA, wherein the catalyst, preparation method and application thereof are composed of MnFe2O4 nanocores, SiO2 coating layer and surface-loaded metal dopant M. The catalyst is calcined to form Lewis acid sites on the SiO2 surface.

[0007] Furthermore, the metal dopant M is selected from Zn or Al; the calcination temperature is 500-600℃.

[0008] Furthermore, the saturation magnetization Ms of the catalyst is 20-40 emu·g. -1 The coercivity Hc is 50-100 Oe, and the specific surface area is 20-30 m². 2 ·g-1 The average pore size ranges from 17 to 27 nm.

[0009] Furthermore, when the metal dopant M is Zn, the saturation magnetization Ms of the catalyst is 38.5 emu·g. -1 The coercivity Hc is 60 Oe, and the specific surface area is 21.32 m². 2 ·g -1 ; When the metal dopant M is Al, the saturation magnetization Ms of the catalyst is 25.0 emu·g. -1 The coercivity Hc is 80 Oe, and the specific surface area is 26.71 m². 2 ·g -1 .

[0010] Another aspect of the present invention provides a method for preparing the catalyst for the enzyme-free synthesis of phospholipid DHA / DPA according to any one of the above-mentioned methods, comprising the following steps: (1) MnFe2O4 nanonuclei were prepared by hydrothermal method from manganese chloride tetrahydrate and ferric chloride hexahydrate; (2) TEOS deposited SiO2 on the surface of MnFe2O4 nanonuclei by in-situ hydrolysis in an ethanol / water / ammonia system to obtain MnFe2O4-SiO2; (3) The catalyst for the enzyme-free synthesis of phospholipid DHA / DPA was prepared by adding a metal precursor dropwise to an anhydrous ethanol suspension of MnFe2O4-SiO2, dispersing and calcining it.

[0011] Further, the specific method of step (1) is as follows: using anhydrous sodium acetate as a stabilizer, a solution of manganese chloride tetrahydrate and ferric chloride hexahydrate is prepared in deionized water, NaOH is added to adjust the pH to alkaline, the container is sealed and the temperature is raised to 180-200℃ and kept at that temperature for 10-12 hours, and after natural cooling, it is washed and vacuum dried to obtain the MnFe2O4 nanonucleus. The specific method of step (2) is as follows: MnFe2O4 nanonuclei are dispersed in anhydrous ethanol, ammonia and deionized water are added and stirred, then TEOS is added dropwise, stirred at 20-25℃ for 10-12 hours, washed and vacuum dried to obtain the MnFe2O4-SiO2; The specific method of step (3) is as follows: MnFe2O4-SiO2 is dispersed in anhydrous ethanol to form a suspension, ultrasonically dispersed and then a metal precursor is added dropwise. After dispersion for 6-8 hours, the suspension is vacuum dried for 10-12 hours and then calcined at high temperature to obtain the catalyst for the enzyme-free synthesis of phospholipid DHA / DPA.

[0012] Furthermore, in step (1), the molar ratio of manganese chloride tetrahydrate to ferric chloride hexahydrate is 1:1.5-3, and the pH is 12-13; In step (2), the volume ratio of anhydrous ethanol, deionized water and ammonia is (150-200):(30-50):(3-8), and the concentration of ammonia is 25%-28%; the amount of TEOS added is 8-10 mL per 2.0 g MnFe2O4 suspension. In step (3), the concentration of the MnFe2O4-SiO2 anhydrous ethanol suspension is 0.50-0.52 g / 50 mL; the metal precursor is selected from Zn(CH3COO)2 or Al(OC3H7)3, the molar ratio of metal to Si is 1:30-35, and the calcination temperature is 500-600℃.

[0013] Finally, this invention also provides the application of any of the above-mentioned catalysts for the enzymatic synthesis of phospholipid DHA / DPA in the synthesis of phospholipid DHA / DPA, comprising the following steps: (1) Dissolve AOT in n-hexane, add phosphate buffer, and add free fatty acids rich in DHA / DPA and soybean lecithin. Mix well and prepare a reverse microemulsion system. (2) Add a catalyst for the enzyme-free synthesis of phospholipid DHA / DPA to the reverse microemulsion system and react for a certain time at the reaction temperature; (3) After the reaction is completed, the catalyst used for the enzyme-free synthesis of phospholipid DHA / DPA is recovered by an external magnetic field, and the product is subjected to rotary evaporation, acetone washing and purification to obtain phospholipid DHA / DPA.

[0014] Furthermore, in the reverse microemulsion system, the mass ratio of free fatty acids to soybean lecithin is 2-18:1; the amount of catalyst added is 2-10 wt% of the substrate; the reaction temperature is 10-50℃; and the reaction time is 12-36 hours.

[0015] Furthermore, when the catalyst is MnFe2O4-SiO2@Zn at 550℃, under the conditions of a free fatty acid to soybean lecithin mass ratio of 14:1, 8wt% catalyst addition, 30℃, and 30h, the DHA incorporation rate is 53.53%, and the DPA incorporation rate is 12.86%. When the catalyst is MnFe2O4-SiO2@Al-550℃, under the conditions of a free fatty acid to soybean lecithin mass ratio of 10:1, 6wt% catalyst addition, 30℃, and 30h, the DHA incorporation rate is 51.77% and the DPA incorporation rate is 12.34%.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) The catalyst provided by the present invention for the enzyme-free synthesis of phospholipid DHA / DPA has both good magnetic responsiveness and regulated surface acidity. It can achieve efficient non-enzymatic transesterification / acyl exchange reaction in reverse microemulsion system and achieve a high incorporation rate. At the same time, it avoids the use of enzymes and can effectively avoid the defects of high cost, sensitive reaction system and poor solvent resistance, thus expanding the application range.

[0017] (2) The catalyst provided by the present invention for the enzyme-free synthesis of phospholipid DHA / DPA has excellent magnetic response capability, is easy to magnetically separate and recover, has good recycling performance, and is suitable for industrial scale-up production.

[0018] (3) In the catalyst provided by the present invention for the enzyme-free synthesis of phospholipid DHA / DPA, MnFe2O4 has excellent magnetic response capability and can achieve rapid separation; the SiO2 shell can provide a stable structure and tunable surface properties; the introduction of Zn or Al can form Lewis acid sites on the material surface, further enhancing the catalytic ability for acyl exchange and transesterification reactions. Attached Figure Description

[0019] Figure 1 XRD patterns of MnFe2O4, MnFe2O4-SiO2 and MnFe2O4-SiO2@M-550℃ (M=Zn, Al) prepared in Examples 1, 2 and 3; Figure 2 The flowchart shows the process of synthesizing phospholipid-type DHA by MnFe2O4-SiO2@M-550℃ (M=Zn, Al) prepared in Examples 1, 2, and 3. Figure 3 SEM image of MnFe2O4-SiO2@M-550℃ (M=Zn, Al) prepared in Example 1; Figure 4 SEM image of MnFe2O4-SiO2@M-550℃ (M=Zn, Al) prepared in Example 2; Figure 5 SEM image of MnFe2O4-SiO2@M-550℃ (M=Zn, Al) prepared in Example 3. Detailed Implementation

[0020] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] Example 1: 1. The catalyst MnFe2O4-SiO2@M-550℃ (M=Zn, Al) for the enzyme-free synthesis of phospholipids DHA / DPA was prepared by the following steps: (1) Using anhydrous sodium acetate as a stabilizer, a solution of manganese chloride tetrahydrate and ferric chloride hexahydrate was prepared in deionized water. The molar ratio of manganese chloride tetrahydrate to ferric chloride hexahydrate was 1:2. NaOH was added to adjust the pH to 13. The system was sealed using a Teflon-lined autoclave. The temperature was then raised to 180°C and kept at that temperature for 10 hours. After natural cooling, the system was washed and vacuum dried at 80°C for 8 hours to obtain MnFe2O4 nanonuclei. (2) MnFe2O4 nanonuclei were dispersed in anhydrous ethanol, and ammonia and deionized water were added and stirred. The volume ratio of anhydrous ethanol, deionized water and ammonia was 160:40:5; the ammonia concentration was 25%. Then TEOS was added dropwise. The amount of TEOS was 8 mL (for a 2.0 g MnFe2O4 suspension system). After stirring at 20 °C for 10 hours, the mixture was washed and vacuum dried at 60 °C for 6 hours to obtain MnFe2O4-SiO2. (3) MnFe2O4-SiO2 was dispersed in anhydrous ethanol to prepare a suspension with a concentration of 0.50 g / 50 mL. After ultrasonic dispersion, metal precursors Zn(CH3COO)2 or Al(OC3H7)3 were added dropwise. The molar ratio of metal to Si was 1:30. After dispersion for 6 hours, vacuum drying was carried out at 60 °C for 10 h, and calcination was carried out at 550 °C for 5 h to obtain the catalyst MnFe2O4-SiO2@Zn-550 °C or MnFe2O4-SiO2@Al-550 °C for the enzyme-free synthesis of phospholipid DHA / DPA. 2. The catalyst used for the enzymatic synthesis of phospholipid DHA / DPA is applied to the catalytic synthesis of phospholipid-type DHA / DPA through the following steps: (1) Dissolve AOT in n-hexane, add phosphate buffer, and add free fatty acids rich in DHA / DPA and soybean lecithin. Mix well and prepare a reverse microemulsion system. (2) Add a catalyst for the enzyme-free synthesis of phospholipid DHA / DPA to the reverse microemulsion system and react for a certain time at the reaction temperature; (3) After the reaction is completed, the catalyst used for the enzyme-free synthesis of phospholipid DHA / DPA is recovered by an external magnetic field, and the product is subjected to rotary evaporation, acetone washing and purification to obtain phospholipid DHA / DPA; During the catalytic process, the mass ratio of free fatty acids to soybean lecithin (FFA:PC) in the reverse microemulsion system was 6:1, the catalyst dosage was 113 mg (6 wt% relative to the substrate), the reaction temperature was 20 °C, and the reaction time was 18 h.

[0022] Example 2: 1. The catalyst MnFe2O4-SiO2@M-550℃ (M=Zn, Al) for the enzyme-free synthesis of phospholipids DHA / DPA was prepared by the following steps: (1) Using anhydrous sodium acetate as a stabilizer, a solution of manganese chloride tetrahydrate and ferric chloride hexahydrate was prepared in deionized water with a molar ratio of 1:2. NaOH was added to adjust the pH to 13. The system was sealed using a Teflon-lined autoclave. The temperature was then raised to 190°C and kept at that temperature for 11 hours. After natural cooling, the system was washed and vacuum dried at 80°C for 9 hours to obtain MnFe2O4 nanonuclei. (2) MnFe2O4 nanonuclei were dispersed in anhydrous ethanol, and ammonia and deionized water were added and stirred. The volume ratio of anhydrous ethanol, deionized water and ammonia was 160:40:5; the concentration of ammonia was 27%. Then TEOS was added dropwise. The amount of TEOS was 9 mL (for a 2.0 g MnFe2O4 suspension system). After stirring at 20 °C for 11 hours, the mixture was washed and vacuum dried at 70 °C for 6 hours to obtain MnFe2O4-SiO2. (3) MnFe2O4-SiO2 was dispersed in anhydrous ethanol to prepare a suspension with a concentration of 0.51 g / 50 mL. After ultrasonic dispersion, metal precursors Zn(CH3COO)2 or Al(OC3H7)3 were added dropwise. The molar ratio of metal to Si was 1:33. After dispersion for 7 hours, the mixture was vacuum dried at 60 °C for 11 hours and calcined at 550 °C for 5 hours to obtain the catalyst MnFe2O4-SiO2@Zn-550 °C or MnFe2O4-SiO2@Al-550 °C for the enzyme-free synthesis of phospholipid DHA / DPA. 2. The catalyst used for the enzymatic synthesis of phospholipid DHA / DPA is applied to the catalytic synthesis of phospholipid-type DHA / DPA through the following steps: (1) Dissolve AOT in n-hexane, add phosphate buffer, and add free fatty acids rich in DHA / DPA and soybean lecithin. Mix well and prepare a reverse microemulsion system. (2) Add a catalyst for the enzyme-free synthesis of phospholipid DHA / DPA to the reverse microemulsion system and react for a certain time at the reaction temperature; (3) After the reaction is completed, the catalyst used for the enzyme-free synthesis of phospholipid DHA / DPA is recovered by an external magnetic field, and the product is subjected to rotary evaporation, acetone washing and purification to obtain phospholipid DHA / DPA; During the catalytic process, the mass ratio of free fatty acids to soybean lecithin (FFA:PC) in the reverse microemulsion system was 10:1, the catalyst dosage was 171 mg (7 wt% relative to the substrate), the reaction temperature was 30 °C, and the reaction time was 24 h.

[0023] Example 3: 1. The catalyst MnFe2O4-SiO2@M-550℃ (M=Zn, Al) for the enzyme-free synthesis of phospholipids DHA / DPA was prepared by the following steps: (1) Using anhydrous sodium acetate as a stabilizer, a solution of manganese chloride tetrahydrate and ferric chloride hexahydrate was prepared in deionized water with a molar ratio of 1:2. NaOH was added to adjust the pH to 13. The system was sealed using a Teflon-lined autoclave. The temperature was then raised to 200°C and kept at that temperature for 12 hours. After natural cooling, the system was washed and vacuum dried at 80°C for 10 hours to obtain MnFe2O4 nanonuclei. (2) MnFe2O4 nanonuclei were dispersed in anhydrous ethanol, and ammonia and deionized water were added and stirred. The volume ratio of anhydrous ethanol, deionized water and ammonia was 160:40:5; the concentration of ammonia was 28%. Then TEOS was added dropwise. The amount of TEOS was 10 mL (for a 2.0 g MnFe2O4 suspension system). After stirring at 20 °C for 12 hours, the mixture was washed and vacuum dried at 80 °C for 6 hours to obtain MnFe2O4-SiO2. (3) MnFe2O4-SiO2 was dispersed in anhydrous ethanol to prepare a suspension with a concentration of 0.52 g / 50 mL. After ultrasonic dispersion, metal precursors Zn(CH3COO)2 or Al(OC3H7)3 were added dropwise. The molar ratio of metal to Si was 1:35. After dispersion for 8 hours, the mixture was vacuum dried at 60 °C for 11 h and calcined at 550 °C for 5 h to obtain the catalyst MnFe2O4-SiO2@Zn-550 °C or MnFe2O4-SiO2@Al-550 °C for the enzyme-free synthesis of phospholipid DHA / DPA. 2. The catalyst used for the enzymatic synthesis of phospholipid DHA / DPA is applied to the catalytic synthesis of phospholipid-type DHA / DPA through the following steps: (1) Dissolve AOT in n-hexane, add phosphate buffer, and add free fatty acids rich in DHA / DPA and soybean lecithin. Mix well and prepare a reverse microemulsion system. (2) Add a catalyst for the enzyme-free synthesis of phospholipid DHA / DPA to the reverse microemulsion system and react for a certain time at the reaction temperature; (3) After the reaction is completed, the catalyst used for the enzyme-free synthesis of phospholipid DHA / DPA is recovered by an external magnetic field, and the product is subjected to rotary evaporation, acetone washing and purification to obtain phospholipid DHA / DPA; During the catalytic process, the mass ratio of free fatty acids to soybean lecithin (FFA:PC) in the reverse microemulsion system was 14:1, the catalyst dosage was 228 mg (8 wt% relative to the substrate), the reaction temperature was 40 °C, and the reaction time was 30 h.

[0024] Performance testing The DHA / DPA incorporation rates of MnFe2O4-SiO2@Zn-550℃ and MnFe2O4-SiO2@Al-550℃ under different reaction conditions in Examples 1-3 are shown in the table below:

[0025] As can be seen from the incorporation rate results in the table above, the catalyst provided by this invention for the enzyme-free synthesis of phospholipid DHA / DPA has excellent catalytic efficiency for the synthesis of DHA / DPA.

[0026] The XRD patterns of MnFe2O4, MnFe2O4-SiO2, MnFe2O4-SiO2@Zn-550℃ and MnFe2O4-SiO2@Al-550℃ prepared in Examples 1-3 are as follows: Figure 1 As shown, this indicates that the composite material was successfully prepared.

[0027] like Figure 3-5 The images show scanning electron microscope (SEM) images of the catalysts MnFe2O4-SiO2@Zn and MnFe2O4-SiO2@Al prepared in Examples 1-3 for the enzyme-free synthesis of phospholipid DHA / DPA. It can be seen that the Zn and Al doped samples have a dense spherical particle agglomeration structure with more irregular microstructures attached to the surface, showing that different metal doping forms a differentiated surface morphology and acidic site distribution on the SiO2 surface.

[0028] In summary, the MnFe2O4-SiO2@M-550℃ (M=Zn, Al) catalyst constructed in this invention for the enzyme-free synthesis of phospholipid DHA / DPA has the characteristics of structural stability, convenient magnetic separation, and high catalytic efficiency. It can realize the efficient synthesis of phospholipid DHA / DPA under mild conditions and is suitable for the green manufacturing and industrial application of functional lipids.

[0029] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A catalyst for the enzyme-free synthesis of phospholipids DHA / DPA, characterized in that, The catalyst used for the enzyme-free synthesis of phospholipid DHA / DPA consists of a MnFe2O4 nanocore, a SiO2 coating layer, and a surface-loaded metal dopant M. The catalyst is calcined to form Lewis acid sites on the SiO2 surface.

2. The catalyst for the enzyme-free synthesis of phospholipid DHA / DPA according to claim 1, characterized in that, The metal dopant M is selected from Zn or Al; the calcination temperature is 500-600℃.

3. The catalyst for the enzyme-free synthesis of phospholipid DHA / DPA according to claim 1, characterized in that, The saturation magnetization Ms of the catalyst is 20-40 emu·g. -1 The coercivity Hc is 50-100 Oe, and the specific surface area is 20-30 m². 2 ·g -1 The average pore size ranges from 17 to 27 nm.

4. The catalyst for the enzyme-free synthesis of phospholipid DHA / DPA according to claim 3, characterized in that, When the metal dopant M is Zn, the saturation magnetization Ms of the catalyst is 38.5 emu·g. -1 The coercivity Hc is 60 Oe, and the specific surface area is 21.32 m². 2 ·g -1 ; When the metal dopant M is Al, the saturation magnetization Ms of the catalyst is 25.0 emu·g. -1 The coercivity Hc is 80 Oe, and the specific surface area is 26.71 m². 2 ·g -1 .

5. The method for preparing the catalyst for the enzymatic synthesis of phospholipid DHA / DPA according to any one of claims 1-4, characterized in that, Includes the following steps: (1) MnFe2O4 nanonuclei were prepared by hydrothermal method from manganese chloride tetrahydrate and ferric chloride hexahydrate; (2) TEOS deposited SiO2 on the surface of MnFe2O4 nanonuclei by in-situ hydrolysis in an ethanol / water / ammonia system to obtain MnFe2O4-SiO2; (3) The catalyst for the enzyme-free synthesis of phospholipid DHA / DPA was prepared by adding a metal precursor dropwise to an anhydrous ethanol suspension of MnFe2O4-SiO2, dispersing and calcining it.

6. The method for preparing the catalyst for the enzyme-free synthesis of phospholipid DHA / DPA according to claim 5, characterized in that, The specific method of step (1) is as follows: using anhydrous sodium acetate as a stabilizer, a solution of manganese chloride tetrahydrate and ferric chloride hexahydrate is prepared in deionized water, NaOH is added to adjust the pH to alkaline, the container is sealed and the temperature is raised to 180-200℃ and kept at that temperature for 10-12 hours, and after natural cooling, it is washed and vacuum dried to obtain the MnFe2O4 nanonuclei. The specific method of step (2) is as follows: MnFe2O4 nanonuclei are dispersed in anhydrous ethanol, ammonia and deionized water are added and stirred, then TEOS is added dropwise, stirred at 20-25℃ for 10-12 hours, washed and vacuum dried to obtain the MnFe2O4-SiO2; The specific method of step (3) is as follows: MnFe2O4-SiO2 is dispersed in anhydrous ethanol to form a suspension, ultrasonically dispersed and then a metal precursor is added dropwise. After dispersion for 6-8 hours, the mixture is vacuum dried for 10-12 hours and calcined at high temperature to obtain the catalyst for the enzyme-free synthesis of phospholipid DHA / DPA.

7. The method for preparing the catalyst for the enzyme-free synthesis of phospholipid DHA / DPA according to claim 6, characterized in that, In step (1), the molar ratio of manganese chloride tetrahydrate to ferric chloride hexahydrate is 1:1.5-3, and the pH is 12-13. In step (2), the volume ratio of anhydrous ethanol, deionized water and ammonia is (150-200):(30-50):(3-8), and the concentration of ammonia is 25%-28%; the amount of TEOS added is 8-10 mL per 2.0 g MnFe2O4 suspension. In step (3), the concentration of the MnFe2O4-SiO2 anhydrous ethanol suspension is 0.50-0.52 g / 50 mL; the metal precursor is selected from Zn(CH3COO)2 or Al(OC3H7)3, the molar ratio of metal to Si is 1:30-35, and the calcination temperature is 500-600℃.

8. The application of the catalyst for the enzymatic synthesis of phospholipid DHA / DPA according to any one of claims 1-4 in the synthesis of phospholipid DHA / DPA, characterized in that, Includes the following steps: (1) Dissolve AOT in n-hexane, add phosphate buffer, and add free fatty acids rich in DHA / DPA and soybean lecithin. Mix well and prepare a reverse microemulsion system. (2) Add a catalyst for the enzyme-free synthesis of phospholipid DHA / DPA to the reverse microemulsion system and react for a certain time at the reaction temperature; (3) After the reaction is completed, the catalyst used for the enzyme-free synthesis of phospholipid DHA / DPA is recovered by an external magnetic field, and the product is subjected to rotary evaporation, acetone washing and purification to obtain phospholipid DHA / DPA.

9. The application according to claim 8, characterized in that, The mass ratio of free fatty acids to soybean lecithin in the reverse microemulsion system is 2-18:1; the amount of catalyst added is 2-10 wt% of the substrate; the reaction temperature is 10-50℃; and the reaction time is 12-36 hours.

10. The application according to claim 8, characterized in that, When the catalyst is MnFe2O4-SiO2@Zn at 550℃, under the conditions of a free fatty acid to soybean lecithin mass ratio of 14:1, 8wt% catalyst addition, 30℃, and 30h, the DHA incorporation rate is 53.53% and the DPA incorporation rate is 12.86%. When the catalyst is MnFe2O4-SiO2@Al-550℃, under the conditions of a free fatty acid to soybean lecithin mass ratio of 10:1, 6wt% catalyst addition, 30℃, and 30h, the DHA incorporation rate is 51.77% and the DPA incorporation rate is 12.34%.

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