A method for producing 1,3-diglyceride by immobilizing lipase with imino acid-modified nanomaterials

Abstract

This invention belongs to the field of biochemical technology and relates to a method for producing 1,3-diglyceride by immobilizing lipase with imino-modified nanomaterials. The method involves mixing glycerol, fatty acids, and lipase immobilized with imino-modified nanomaterials, and reacting the mixture at 40–80°C for 1–10 hours with stirring to obtain a mixture containing 1,3-diglyceride. The imino-modified nanomaterials synthesized in this invention serve as a carrier for immobilizing lipase to synthesize 1,3-diglyceride. Compared with lipase immobilized on a carrier without immobilization, the content of 1,3-diglyceride can be increased by nearly 20% when using the immobilized enzyme on the imino-modified carrier. The immobilization method in this invention exposes the active sites of the lipase and facilitates the formation of an oil-water interface, resulting in a higher catalytic effect.

Description

Technical Field

[0001] This invention belongs to the field of biochemical technology and relates to a method for producing 1,3-glycerol diester by immobilizing lipase with imino acid-modified nanomaterials. Background Technology

[0002] As we all know, fats and oils are an essential component of our daily diet. Fats and oils are mainly composed of triglycerides and diglycerides. Diglycerides, depending on the position of the acyl group and glycerol hydroxyl group, are further divided into 1,2-diglycerides and 1,3-diglycerides. The metabolic pathway of 1,3-diglycerides differs from that of 1,2-diglycerides and triglycerides. 1,3-diglycerides are hydrolyzed into free fatty acids and 1-monoglycerides under the catalysis of pancreatic lipase. The 1-monoglycerides are then β-oxidized and released as energy, with very little stored in the body. Therefore, 1,3-diglycerides have functions such as reducing visceral fat, inhibiting weight gain, and increasing blood lipid levels.

[0003] Currently, the main enzymatic methods for producing diglycerides include glycerol hydrolysis, enzymatic hydrolysis, and esterification. Direct esterification offers advantages such as short reaction time, high product purity, and simple operation, making it the preferred method for synthesizing 1,3-diglycerides.

[0004] However, the solvent-free synthesis of 1,3-glycerol diesters involves a high-viscosity heterogeneous system, which can lead to problems such as poor dispersibility, decreased selectivity, and poor stability of lipases in applications. Immobilization technology can improve the stability of lipases. Nanomaterials can significantly improve dispersibility. The strong bond between the metal center and organic ligand of UIO-66, stemming from high framework connectivity, bond polarization, and high charge density, gives it high chemical, thermal, and mechanical stability. Its structure remains stable at 540℃ and in strongly acidic or alkaline solutions. UIO-66 has a large specific surface area, making it an ideal choice for enzyme immobilization. However, immobilization often causes conformational changes in lipases, thereby reducing their catalytic activity. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for producing 1,3-diglyceride by immobilizing lipase with imino acid modified nanomaterials, which is in contrast to the shortcomings of the prior art.

[0006] Invention Concept: Imino acids possess both hydrophilic and hydrophobic ends. The hydrophobic end connects to lipases through hydrophobic interactions, opening the lipase cap and exposing the active site. The hydrophilic end can connect to UIO-66, increasing its hydrophilicity. Grafting imino acids onto UIO-66 crystals can induce beneficial conformational changes in the lipase. This modification enhances the hydrophilicity of UIO-66, facilitating the formation of the oil-water interface and promoting substrate molecule diffusion. This positively impacts the catalytic conversion of oleic acid and glycerol into diglycerides by immobilized lipases.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] This invention discloses a method for producing 1,3-diglyceride by immobilizing lipase with imino acid-modified nanomaterials. Glycerol, fatty acids and immobilized lipase with imino acid-modified nanomaterials are mixed and reacted with stirring at 40-80°C for 1-10 hours to obtain a mixture containing 1,3-diglyceride. Water generated during the reaction is removed using molecular sieves or by vacuuming. When removing water by vacuuming, the vacuum degree of the reaction system is 100-1000 Pa.

[0009] Preferably, lipase immobilized with glycerol, fatty acids and imino acid-modified nanomaterials is mixed and reacted with stirring at 55-65°C for 1-6 hours.

[0010] Preferably, the water generated during the reaction is removed using a molecular sieve or by vacuuming; when vacuuming is used to remove water, the vacuum level of the reaction system is 500–1000 Pa.

[0011] The method for preparing immobilized lipase using imino acid-modified nanomaterials includes the following steps:

[0012] (1) Zirconium chloride, terephthalic acid, benzoic acid and inorganic acid were added to N,N-dimethylformamide and mixed and dissolved to obtain a first mixture; then the first mixture was subjected to a first reaction; after the reaction was completed, the solid and liquid were separated, the solid part was washed and dried to obtain metal-organic framework material UIO-66;

[0013] (2) Dissolve imino acid in ethanol and heat to pretreat to obtain imino acid ethanol solution; add UIO-66 obtained in step (1) to imino acid ethanol solution for second reaction; after the reaction is completed, separate solid and liquid, wash and dry the solid part to obtain imino acid modified nanomaterial UIO-66-imino acid;

[0014] (3) The UIO-66-imino acid obtained in step (2) was added to isopropanol and mixed and dispersed to obtain a second mixture; the lipase was added to phosphate buffer solution to obtain a third mixture; the second mixture and the third mixture were mixed to carry out a third reaction; after the reaction was completed, the supernatant was collected by centrifugation, washed, and freeze-dried to obtain immobilized lipase of imino acid modified nanomaterials.

[0015] Specifically, the fatty acid is any one of unsaturated fatty acids and saturated fatty acids. Preferably, the unsaturated fatty acid is a long-chain unsaturated fatty acid. More preferably, the long-chain unsaturated fatty acid is any one or a combination of oleic acid, linoleic acid and docosahexaenoic acid. Most preferably, it is oleic acid.

[0016] Specifically, the molar ratio of glycerol to fatty acids is 1:1 to 3, preferably 1:1.5 to 2.2, and more preferably 1:2.2; based on the total mass of glycerol, fatty acids and imino acid-modified nanomaterials immobilized lipase, the mass of immobilized lipase is 1% to 10% of the total mass, preferably 1% to 5%, and more preferably 2%.

[0017] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (1), the inorganic acid is concentrated hydrochloric acid or hydrofluoric acid, preferably concentrated hydrochloric acid.

[0018] The concentrated hydrochloric acid is an aqueous solution of hydrochloric acid with a mass fraction of 36% to 38%.

[0019] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (1), the mass-to-volume ratio of zirconium chloride to N,N-dimethylformamide is 1-100 g:1 L, preferably 1-30 g:1 L, further preferably 5-20 g:1 L, even more preferably 10-15 g:1 L, and most preferably 12.96 g:1 L.

[0020] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (1), the mass-to-volume ratio of terephthalic acid to N,N-dimethylformamide is 1-100 g:1 L, preferably 1-30 g:1 L, further preferably 2-16 g:1 L, even more preferably 6-12 g:1 L, and most preferably 9.26 g:1 L.

[0021] Specifically, in the preparation method of immobilized lipase using imino acid-modified nanomaterials, in step (1), the mass-to-volume ratio of benzoic acid to N,N-dimethylformamide is 10-200 g:1 L, preferably 50-160 g:1 L, further preferably 100-160 g:1 L, even more preferably 120-140 g:1 L, and most preferably 134.07 g:1 L.

[0022] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (1), the volume ratio of the inorganic acid to N,N-dimethylformamide is 0.5-1.5 mL:108 mL, preferably 1 mL:108 mL.

[0023] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (1), the first reaction is carried out at a temperature of 100-150°C, preferably 120°C, and for a reaction time of 12-36 h, preferably 24 h.

[0024] Specifically, in the method for preparing immobilized lipase using imino acid-modified nanomaterials, in step (2), the imino acid is proline (Pro) or hydroxyproline (HYP), preferably proline; the concentration of the imino acid in the imino acid ethanol solution is 5-20 mg / mL, preferably 10 mg / mL; the heating pretreatment is performed at a temperature of 30-80℃, preferably 40-60℃, more preferably 50℃, for a heating time of 0.5-2 h, preferably 1 h; and the mass ratio of UIO-66 to imino acid is 0.1-0.5:1, preferably 0.35:1.

[0025] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (2), the second reaction is carried out at a temperature of 30-80°C, preferably 40-60°C, more preferably 50°C, and for a reaction time of 12-36 h, preferably 24 h.

[0026] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (3), the lipase is any one or a combination of several of the following: Candida antarcticis lipase B (CALB), Rhizopus miltiorrhiza lipase (RML), Thermophilic mycelium lipase (TLL), Rhizopus dilatatus lipase (RDL), and Rhizopus miltiorrhiza lipase (ROL), preferably Candida antarcticis lipase B.

[0027] The measured enzyme activity of Candida antarcticis lipase B is 3000-4000 U / mL. One enzyme activity unit (U) of Candida antarcticis lipase B is defined as the amount of lipase required to produce 1.0 μmol of acid per minute by hydrolyzing glycerides under the test conditions of 40℃ and pH=7.

[0028] Specifically, in the method for preparing immobilized lipase using imino acid-modified nanomaterials, in step (3), the concentration of UIO-66-imino acid in the second mixture is 30-80 mg / mL, preferably 40-60 mg / mL, and more preferably 50 mg / mL; the concentration of lipase in the third mixture is 0.1-0.2 mL / mL, preferably 0.12-0.16 mL / mL, and more preferably 0.14 mL / mL; the mass-to-volume ratio of UIO-66-imino acid to lipase is 70-100 mg:1 mL, preferably 89 mg:1 mL.

[0029] In the preparation method of immobilized lipase using imino acid modified nanomaterials, step (3) involves the following preparation method for the phosphate buffer solution: 14.2g of anhydrous disodium hydrogen phosphate is weighed and dissolved in 1000mL of pure water by ultrasonication to form solution A; 12.0g of anhydrous sodium dihydrogen phosphate is weighed and dissolved in 1000mL of pure water by ultrasonication to form solution B; solutions A and B are mixed in proportion to make the final mixture pH=8, which is 0.1M, pH=8 phosphate buffer (PBS).

[0030] Specifically, in the preparation method of immobilized lipase using imino acid modified nanomaterials, in step (3), the third reaction is carried out at a temperature of 20-40°C, preferably 30°C, and for a reaction time of 0.2-1h, preferably 0.5h.

[0031] The third reaction requires shaking during the reaction process, preferably in a shaker.

[0032] Beneficial effects:

[0033] (1) The imino acid-modified nanomaterials synthesized in this invention are used as carriers to immobilize lipases for the synthesis of 1,3-diglycerides. Compared with the synthesis of 1,3-diglycerides catalyzed by lipase immobilized on carriers without imino acid modification, the content of 1,3-diglycerides can be increased by nearly 20% when the enzyme is immobilized on the imino acid-modified carrier. The immobilization method in this invention can expose the active sites of lipases and facilitate the formation of oil-water interfaces, resulting in a higher catalytic effect.

[0034] (2) The immobilized lipase prepared by the present invention has high selectivity and low acyl migration rate during the reaction process. At the same time, it can reduce the proportion of by-product monoglyceride and improve the purity of 1,3-diglyceride in the product.

[0035] (3) The reaction conditions of the present invention are mild, which improves the reaction efficiency and is a high-efficiency, fast and green chemistry-compliant synthesis method. Attached Figure Description

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0037] Figure 1 Electron micrographs of the materials prepared in Examples 1 to 4; wherein, Figure 1 a is a scanning electron microscope image of the metal-organic framework material UIO-66; Figure 1 b is a scanning electron microscope image of the proline-modified nanomaterial UIO-66-Pro; Figure 1 c is a scanning electron microscope image of lipase immobilized by proline-modified nanomaterials. Figure 1 d is a scanning electron microscope image of the hydroxyproline-modified nanomaterial UIO-66-HYP; Figure 1 e is a scanning electron microscope image of lipase immobilized on hydroxyproline-modified nanomaterials.

[0038] Figure 2 The graph shows the effect of the molar ratio of oleic acid and glycerol on the esterification reaction in Examples 5-8.

[0039] Figure 3 The graph shows the effect of the molar ratio of oleic acid and glycerol on the esterification reaction in Examples 9-12.

[0040] Figure 4 The graph shows the effect of reaction temperature on the reaction in Examples 13-15.

[0041] Figure 5 The graph shows the effect of reaction temperature on the reaction in Examples 16-18.

[0042] Figure 6 The graph shows the effect of the amount of proline-modified nanomaterials immobilized with lipase on the reaction in Examples 19-22.

[0043] Figure 7 The graph shows the effect of the amount of hydroxyproline-modified nanomaterials immobilized with lipase on the reaction in Examples 23-26.

[0044] Figure 8 The graph shows the effect of reaction time on the reaction in Examples 27-31.

[0045] Figure 9The graph shows the effect of reaction time on the reaction in Examples 32-36.

[0046] Figure 10 The graph shows the effect of immobilized lipase on the reaction using an immobilized lipase on a carrier with immobilized lipase without immobilized lipase. Detailed Implementation

[0047] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0048] The phosphate buffer solution used in this embodiment of the invention is prepared as follows: 14.2g of anhydrous disodium hydrogen phosphate is weighed and dissolved in 1000mL of pure water by sonication to obtain solution A; 12.0g of anhydrous sodium dihydrogen phosphate is weighed and dissolved in 1000mL of pure water by sonication to obtain solution B; solutions A and B are mixed in proportion to make the final mixture pH=8, which is 0.1M, pH=8 phosphate buffer (PBS).

[0049] The Antarctic Candida lipase B (CALB) used in this embodiment of the invention was purchased from Novozymes, and the measured enzyme activity was 3550.6 U / mL. One enzyme activity unit (U) of Antarctic Candida lipase B is defined as the amount of lipase required to hydrolyze glycerides to produce 1.0 μmol of acid per minute under the test conditions of 40°C and pH=7.

[0050] The concentrated hydrochloric acid used in the embodiments of the present invention is an aqueous solution of hydrochloric acid with a mass fraction of 36% to 38%.

[0051] Example 1: Preparation of proline-modified nanomaterials

[0052] 0.35 g of zirconium chloride, 0.25 g of terephthalic acid, 3.62 g of benzoic acid, and 0.25 mL of concentrated hydrochloric acid were weighed and added to 27 mL of N,N-dimethylformamide solution. The mixture was then sonicated to dissolve the solution, yielding a first mixture. This first mixture was transferred to a polytetrafluoroethylene-lined hydrothermal reactor and reacted at 120 °C for 24 h. After the reaction, the product was collected by centrifugation and washed three times each with N,N-dimethylformamide solution and ethanol solution. The product was then vacuum dried at 150 °C for 12 h to obtain the metal-organic framework material UIO-66. Its scanning electron microscope image is shown below. Figure 1 As shown in a.

[0053] 1 g of proline powder was dissolved in 100 mL of ethanol and heated continuously at 50 °C for 1 h to obtain a proline ethanol solution. 350 mg of UIO-66 was added to the proline ethanol solution, and the mixture was stirred at 50 °C for 24 h. After the reaction was complete, the product was cooled to room temperature, centrifuged at 8000 rpm for 10 min, washed several times with ethanol, and finally dried in a vacuum oven at 100 °C for 12 h to obtain the proline-modified nanomaterial UIO-66-Pro. Its scanning electron microscope image is shown below. Figure 1 As shown in b.

[0054] Example 2: Preparation of lipase immobilized on proline-modified nanomaterials

[0055] 0.05 g of UIO-66-Pro was ultrasonically dispersed in 1 mL of isopropanol solution to obtain a second mixture. Then, the second mixture was added to 4 mL of PBS solution containing CALB (the concentration of CALB in the PBS solution was 0.14 mL / mL). The mixture was placed on a shaker and shaken at 30 °C for 0.5 h. After centrifugation, the supernatant was collected, and the immobilized enzyme was washed with PBS. The enzyme was then lyophilized to obtain proline-modified nanomaterial-immobilized lipase. Its scanning electron microscope image is shown below. Figure 1 As shown in c.

[0056] Example 3: Preparation of hydroxyproline-modified nanomaterials

[0057] The preparation method of hydroxyproline-modified nanomaterials is the same as in Example 1, except that proline is replaced with hydroxyproline. Other parameters are the same as in Example 1. The scanning electron microscope image of the prepared hydroxyproline-modified nanomaterial UIO-66-HYP is shown below. Figure 1 As shown in d.

[0058] Example 4: Preparation of lipase immobilized on hydroxyproline-modified nanomaterials

[0059] The preparation method of lipase immobilized by hydroxyproline-modified nanomaterials is the same as in Example 2, except that UIO-66-Pro is replaced with the hydroxyproline-modified nanomaterial UIO-66-HYP prepared in Example 3. Other parameters are the same as in Example 2. The scanning electron microscope image of the lipase immobilized by the prepared hydroxyproline-modified nanomaterials is shown below. Figure 1 As shown in e.

[0060] Example 5

[0061] Oleic acid and glycerol were added to a 25 mL round-bottom flask in a 1:1 molar ratio. The amount of proline-modified nanomaterial-immobilized lipase (prepared in Example 2) added was 2% of the total substrate mass. The reaction mixture was stirred at 300 rpm, and the temperature was controlled at 65 °C using an oil bath. The vacuum level of the reaction system was controlled at 600 Pa using a vacuum pump, and the reaction was completed after 5 h. After the reaction, 10 μL of the sample was taken out, dissolved in 3 mL of dichloromethane, and the composition of the sample was analyzed by high-performance liquid chromatography (HPLC).

[0062] The HPLC analysis method was as follows: Column type: C 18 Column; evaporative light detection, both nebulization and evaporation temperatures are 70℃; column temperature: 40℃; gradient elution, detection method as follows:

[0063] Time (min) Flow rate (mL / min) Mobile phase A: Acetonitrile (v / v, %) Mobile phase B: Dichloromethane (v / v, %) 0 1.4 100 0 4 1.4 100 0 12 1.4 87 13 25 1.4 87 13 30 1.4 70 30 35 1.4 70 30 45 1.4 20 80 55 1.4 100 0 60 1.4 100 0

[0064] Example 6

[0065] Add oleic acid and glycerol in a 25 mL round-bottom flask at a molar ratio of 1.5:1, and keep the other reaction conditions and parameters the same as in Example 5.

[0066] Example 7

[0067] Add oleic acid and glycerol in a 25 mL round-bottom flask at a molar ratio of 2.2:1, and keep the other reaction conditions and parameters the same as in Example 5.

[0068] Example 8

[0069] Oleic acid and glycerol were added to a 25 mL round-bottom flask in a molar ratio of 3:1, and other reaction conditions and parameters were the same as in Example 5. The HPLC detection results of Examples 5-8 are as follows: Figure 2 As shown.

[0070] Example 9

[0071] Same as Example 5, except that the proline-modified nanomaterial immobilized lipase in Example 5 was replaced with hydroxyproline-modified nanomaterial immobilized lipase (prepared in Example 4). The amount of hydroxyproline-modified nanomaterial immobilized lipase added accounted for 2% of the total mass of the substrate. Other reaction conditions and parameters were the same as in Example 5.

[0072] Example 10

[0073] Add oleic acid and glycerol in a 25 mL round-bottom flask at a molar ratio of 1.5:1, and follow the same reaction conditions and parameters as in Example 9.

[0074] Example 11

[0075] Add oleic acid and glycerol in a 25 mL round-bottom flask at a molar ratio of 2.2:1, and keep the other reaction conditions and parameters the same as in Example 9.

[0076] Example 12

[0077] Oleic acid and glycerol were added to a 25 mL round-bottom flask in a molar ratio of 3:1, and other reaction conditions and parameters were the same as in Example 9. The HPLC results of Examples 9-12 are as follows: Figure 3 As shown.

[0078] Examples 13-15

[0079] In Examples 13-15, the reaction temperatures were 55℃, 65℃, and 75℃, respectively; the molar ratio of oleic acid to glycerol was 2.2:1; the amount of proline-modified nanomaterial-immobilized lipase added was 2%; and the reaction was completed after 5 hours. HPLC results are shown below. Figure 4 As shown.

[0080] Examples 16-18

[0081] In Examples 16-18, the reaction temperatures were 55℃, 65℃, and 75℃, respectively; the molar ratio of oleic acid to glycerol was 2.2:1; the amount of lipase immobilized by the hydroxyproline-modified nanomaterial was 2%; and the reaction was completed after 5 hours. HPLC results are shown below. Figure 5 As shown.

[0082] Examples 19-22

[0083] In Examples 19-22, the amounts of proline-modified nanomaterials immobilized with lipase were 1%, 2%, 3%, and 4%, respectively; the molar ratio of oleic acid to glycerol was 2.2:1; the reaction temperature was 65℃; and the reaction time was 5 h. HPLC results are shown below. Figure 6 As shown.

[0084] Examples 23-26

[0085] In Examples 23-26, the amounts of hydroxyproline-modified nanomaterials immobilized with lipase were 1%, 2%, 3%, and 4%, respectively; the molar ratio of oleic acid to glycerol was 2.2:1; the reaction temperature was 65℃; and the reaction time was 5 h. HPLC results are shown below. Figure 7 As shown.

[0086] Examples 27-31

[0087] In Examples 27-31, the reaction times were 1 h, 2 h, 3 h, 4 h, and 5 h, respectively; the molar ratio of oleic acid to glycerol was 2.2:1; the amount of proline-modified nanomaterial-immobilized lipase added was 2%; and the reaction temperature was 65 °C. HPLC results are as follows: Figure 8 As shown.

[0088] Examples 32-36

[0089] In Examples 32-36, the reaction times were 1 h, 2 h, 3 h, 4 h, and 5 h, respectively; the molar ratio of oleic acid to glycerol was 2.2:1; the amount of lipase immobilized by the hydroxyproline-modified nanomaterial was 2%; and the reaction temperature was 65 °C. HPLC results are shown below. Figure 9 As shown.

[0090] Examples 37-39

[0091] In Examples 37-39, 2% proline-modified carrier-immobilized lipase, 2% hydroxyproline-modified carrier-immobilized lipase, and unmodified carrier lipase (CALB) were added, respectively. The molar ratio of oleic acid to glycerol was 2.2:1, the reaction temperature was 65℃, and the reaction time was 5 h. HPLC results are shown below. Figure 10 As shown.

[0092] This invention provides a method for producing 1,3-diglyceride by immobilizing lipases with imino acid-modified nanomaterials. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for the production of 1,3-diglycerides by imino acid-modified nanomaterial-immobilized lipase, characterized by, The glycerol, fatty acid and imino acid modified nanomaterial immobilized lipase are mixed, and the mixture is stirred at 40~80 o C for 1~10 h to obtain a mixture containing 1,3-diglyceride; the water generated in the reaction is removed by using molecular sieves or vacuumizing; when the water is removed by vacuumizing, the vacuum degree of the reaction system is 100~1000 pa; The preparation method of the imino acid modified nanomaterial immobilized lipase comprises the following steps: (1) Zirconium chloride, terephthalic acid, benzoic acid and inorganic acid are added to N,N-dimethylformamide for mixing and dissolving to obtain a first mixed solution; then the first mixed solution is subjected to a first reaction; after the reaction is completed, solid-liquid separation is performed, and the solid part is washed and dried to obtain a metal organic framework material UIO-66; (2) The imino acid is dissolved in ethanol and subjected to heat pretreatment to obtain an imino acid ethanol solution; the UIO-66 obtained in step (1) is added to the imino acid ethanol solution for a second reaction; after the reaction is completed, solid-liquid separation is performed, and the solid part is washed and dried to obtain the imino acid modified nanomaterial UIO-66-imino acid; (3) The UIO-66-imino acid obtained in step (2) is added to isopropanol for mixing and dispersing to obtain a second mixed solution; the lipase is added to a phosphate buffer solution to obtain a third mixed solution; the second mixed solution and the third mixed solution are mixed for a third reaction; after the reaction is completed, the supernatant is obtained by centrifugation, and then washing, freeze-drying are performed to obtain the imino acid modified nanomaterial immobilized lipase; In step (3), the lipase is Candida antarctica lipase B; In step (2), the imino acid is proline or hydroxyproline; In step (1), the first reaction is performed at a temperature of 100-150 DEG C for 12-36 hours; In step (2), the second reaction has a reaction temperature of 30-80 o C and a reaction time of 12-36 h. In step (3), the third reaction is performed at a temperature of 20-40 DEG C for 0.2-1 hour.

2. The method of claim 1, wherein, The fatty acid is any one of an unsaturated fatty acid and a saturated fatty acid; the unsaturated fatty acid is a long-chain unsaturated fatty acid; the long-chain unsaturated fatty acid is any one or a combination of several of oleic acid, linoleic acid and docosahexaenoic acid.

3. The method of claim 1, wherein, The molar ratio of glycerol to fatty acid is 1:1-3; based on the total mass of glycerol, fatty acid and imino acid modified nanomaterial immobilized lipase, the mass of the imino acid modified nanomaterial immobilized lipase accounts for 1%-10% of the total mass.

4. The method of claim 1, wherein, In step (1) of the preparation method of the imino acid modified nanomaterial immobilized lipase, the inorganic acid is concentrated hydrochloric acid or hydrofluoric acid; the mass-volume ratio of zirconium chloride to N,N-dimethylformamide is 1-100 g:1 L; the mass-volume ratio of terephthalic acid to N,N-dimethylformamide is 1-100 g:1 L; the mass-volume ratio of benzoic acid to N,N-dimethylformamide is 10-200 g:1 L; and the volume ratio of the inorganic acid to N,N-dimethylformamide is 0.5-1.5 mL:108 mL.

5. The method of claim 1, wherein, The preparation method of the imino acid modified nanomaterial immobilized lipase, in step (2), the concentration of the imino acid in the imino acid ethanol solution is 5-20 mg / mL; the heating pretreatment is performed at a heating temperature of 30-80 o C, and the heating time is 0.5-2 h; and the mass ratio of the UIO-66 to the imino acid is 0.1-0.5:

1.

6. The method of claim 1, wherein, The preparation method of the imino acid modified nanomaterial immobilized lipase, in step (3), the concentration of UIO-66-imino acid in the second mixed solution is 30-80 mg / mL; the concentration of lipase in the third mixed solution is 0.1-0.2 mL / mL; and the mass-volume ratio of UIO-66-imino acid to lipase is 70-100 mg:1 mL.

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