Method for extracting polyunsaturated fatty acid from marine microalgae
By using methylthio groups-containing compounds and methanol as extraction agents, combined with saponification and crystallization steps, the marine microalgae extracts polyunsaturated fatty acids, which solves the problem of poor yield and purity in the prior art, and achieves a more efficient extraction effect.
Patent Information
- Application Number
- CN202510211929.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-25
- Publication Date
- 2025-06-06
AI Technical Summary
The yield and purity of polyunsaturated fatty acids extracted from marine microalgae in the prior art are not ideal.
Marine microalgae are grinded and extracted by saponification and crystallization steps to improve the yield and purity of polyunsaturated fatty acids.
By defining the volume ratio of the extractant and pretreatment before grinding, the yield and purity of the polyunsaturated fatty acids are significantly improved, and the problem of unsatisfactory extraction amount and purity in the prior art is solved.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of functional oil extraction, and in particular to a method for extracting polyunsaturated fatty acids from marine microalgae. Background Art
[0002] Polyunsaturated fatty acids refer to branched fatty acids with two or more double bonds in their chemical structure. Depending on the position of the first double bond from the methyl-terminal carbon atom, they can be classified into ω-3, ω-6, ω-7 and ω-9. ω-3 and ω-6 are essential to human health and have the effects of maintaining skin health, improving intelligence and brain health, preventing cardiovascular diseases, inhibiting tumors, and preventing cancer. However, the human body cannot synthesize ω-3 and ω-6 polyunsaturated fatty acids by itself and must obtain them through diet.
[0003] Seaweed has great potential as a source of polyunsaturated fatty acids. Marine microalgae account for about 40.68% of marine species. They have the characteristics of short fermentation cycle, high oil content, strong adaptability to the environment, high bioconversion rate, etc., and have extremely high industrial production potential. At present, most polyunsaturated fatty acids are extracted from marine microalgae, but the extraction amount and purity of the extracted polyunsaturated fatty acids are not ideal. Summary of the invention
[0004] The present invention provides a method for extracting polyunsaturated fatty acids from marine microalgae, which solves the problems of low yield and low purity of polyunsaturated fatty acids extracted from marine microalgae in the related art.
[0005] The technical solution of the present invention is as follows: The present invention provides a method for extracting polyunsaturated fatty acids from marine microalgae, comprising the following steps: S1, grinding the marine microalgae for extraction, collecting the extract, and evaporating to dryness to obtain crude marine microalgae lipids; S2, dissolving the crude lipid of marine microalgae, and drying with nitrogen to obtain a dry product; S3, mixing the dried product with a methanol solution of potassium hydroxide for saponification, adjusting the pH value to 1-2, adding water and layering, centrifuging, and collecting the upper oil layer; S4, mixing the oil layer with a methanol solution of urea, crystallizing, washing with water, and centrifuging to obtain polyunsaturated fatty acids; During the extraction in S1, the extractant includes a compound containing a methylthio group and methanol.
[0006] As a further technical solution, the compound containing a methylthio group is 4-methoxythioanisole.
[0007] As a further technical solution, the volume ratio of 4-methoxythioanisole to methanol is 3-9:1.
[0008] As a further technical solution, the volume ratio of 4-methoxythioanisole to methanol is 4-7:1.
[0009] The present invention further improves the yield and purity of polyunsaturated fatty acids extracted from marine microalgae by limiting the volume ratio of 4-methoxythioanisole to methanol to 4-7:1.
[0010] As a further technical solution, pretreatment is performed before grinding, and the pretreatment specifically comprises: soaking the marine microalgae in a copper oxide ammonia solution, filtering, washing with water, and drying.
[0011] The invention further improves the yield and purity of polyunsaturated fatty acids extracted from marine microalgae by pre-treating with copper oxide ammonia solution before grinding.
[0012] As a further technical solution, the mass ratio of the marine microalgae to the copper oxide ammonia solution is 1-5:30.
[0013] As a further technical solution, when dissolving in S2, the solvent used includes chloroform and methanol in a volume ratio of 1 to 9:1.
[0014] The present invention further improves the yield and purity of polyunsaturated fatty acids extracted from marine microalgae by limiting the solvent used in S2 to include chloroform and methanol in a volume ratio of 1 to 9:1.
[0015] As a further technical solution, the volume ratio of chloroform to methanol is 7-8:1.
[0016] The present invention further improves the yield and purity of polyunsaturated fatty acids extracted from marine microalgae by limiting the volume ratio of chloroform to methanol to 7-8:1.
[0017] As a further technical solution, the mass ratio of the marine microalgae crude lipid to the solvent is 1:3-5.
[0018] As a further technical solution, the marine microalgae include one or more of Phaeochromis tricornutum, Porphyridium cruentum, and halogenated microalgae.
[0019] As a further technical solution, the mass ratio of the marine microalgae to the extractant is 1:20-30. The working principle and beneficial effects of the present invention are: In the present invention, a compound containing a methylthio group and methanol are selected as extractants to extract polyunsaturated fatty acids from marine microalgae. The methylthio group-containing compound-methanol mixed solvent has good solubility for marine microalgae crude lipids, thereby improving the yield and purity of the marine microalgae crude lipids extracted from the marine microalgae, thereby improving the yield and purity of the polyunsaturated fatty acids extracted from the marine microalgae crude lipids. DETAILED DESCRIPTION
[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.
[0021] The parameters of the raw materials in the following examples and comparative examples are as follows: Potassium hydroxide methanol solution: homemade, 0.4 mol / L; Dilute hydrochloric acid solution: 10vt%; Urea methanol solution: homemade, 16.7wt%; Copper oxide ammonia solution: homemade, 50g / L.
[0022] Example 1 The method for extracting polyunsaturated fatty acids from marine microalgae comprises the following steps: S1. Grind 1 part of triangular brown finger algae into 100 mesh triangular brown finger algae powder, and put it and 20 parts of methanol solution of 4-methoxythioanisole (the mass ratio of 4-methoxythioanisole to methanol is 3:1) into corresponding positions of Soxhlet extractor, reflux extract at 70°C for 8h, collect the extract, and evaporate the extract at 40°C to dryness to obtain crude marine microalgae lipid; S2, dissolving the crude lipid of marine microalgae in petroleum ether equivalent to 3 times of its weight, and drying with nitrogen gas to obtain a dry product; S3, the dried product was mixed with an equal volume of a methanol solution of potassium hydroxide, saponified for 6 hours, the pH value was adjusted to 1 with a dilute hydrochloric acid solution, water was added to separate the layers, the mixture was centrifuged, and the upper oil layer was collected; S4. Mix the oil layer with an equal volume of urea-methanol solution, crystallize at -20°C for 2 hours, wash with water, and centrifuge to obtain polyunsaturated fatty acids.
[0023] Example 2 The method for extracting polyunsaturated fatty acids from marine microalgae comprises the following steps: S1. Grind 1 part of Porphyridium cruentum into 100-mesh Porphyridium cruentum powder, and put it and 30 parts of methanol solution of 4-methoxythioanisole (the mass ratio of 4-methoxythioanisole to methanol is 9:1) into corresponding positions of Soxhlet extractor, reflux extract at 70°C for 8h, collect the extract, and evaporate the extract at 40°C to dryness to obtain crude marine microalgae lipid; S2, dissolving the crude lipid of marine microalgae in petroleum ether equivalent to 5 times of its weight, and drying with nitrogen gas to obtain a dry product; S3, the dried product was mixed with an equal volume of a methanol solution of potassium hydroxide, saponified for 6 hours, the pH value was adjusted to 2 with a dilute hydrochloric acid solution, water was added to separate the layers, the mixture was centrifuged, and the upper oil layer was collected; S4. Mix the oil layer with an equal volume of urea-methanol solution, crystallize at -20°C for 2 hours, wash with water, and centrifuge to obtain polyunsaturated fatty acids.
[0024] Example 3 The only difference from Example 1 is that the mass ratio of 4-methoxythioanisole to methanol is 9:1.
[0025] Example 4 The only difference from Example 1 is that the mass ratio of 4-methoxythioanisole to methanol is 4:1.
[0026] Example 5 The only difference from Example 1 is that the mass ratio of 4-methoxythioanisole to methanol is 7:1.
[0027] Example 6 The method for extracting polyunsaturated fatty acids from marine microalgae comprises the following steps: S1, soaking 2 parts of triangular phytosalis in 30 parts of copper oxide ammonia solution for 10 minutes, filtering, washing, and drying to obtain pretreated marine microalgae; S2, grinding 1 part of the pretreated marine microalgae into 100-mesh brown finger algae powder, and putting it and 20 parts of 4-methoxythioanisole methanol solution (the mass ratio of 4-methoxythioanisole to methanol is 7:1) into the corresponding positions of the Soxhlet extractor, reflux extraction at 70°C for 8h, collecting the extract, and evaporating the extract at 40°C to obtain crude marine microalgae lipid; S3, dissolving the crude lipid of marine microalgae in petroleum ether equivalent to 3 times of its weight, and drying with nitrogen gas to obtain a dry product; S4, the dried product was mixed with an equal volume of a methanol solution of potassium hydroxide, saponified for 6 hours, the pH value was adjusted to 1 with a dilute hydrochloric acid solution, water was added to separate the layers, the mixture was centrifuged, and the upper oil layer was collected; S5. Mix the oil layer with an equal volume of urea-methanol solution, crystallize at -20°C for 2 hours, wash with water, and centrifuge to obtain polyunsaturated fatty acids.
[0028] Example 7 The only difference from Example 6 is that petroleum ether is replaced by an equal amount of chloroform methanol solution (the mass ratio of chloroform to sodium methoxide is 1:1).
[0029] Example 8 The only difference from Example 7 is that the mass ratio of chloroform to sodium methoxide is 9:1.
[0030] Example 9 The only difference from Example 7 is that the mass ratio of chloroform to sodium methoxide is 7:1.
[0031] Example 10 The only difference from Example 7 is that the mass ratio of chloroform to sodium methoxide is 8:1.
[0032] Comparative Example 1 The method for extracting polyunsaturated fatty acids from marine microalgae comprises the following steps: S1. Grind 1 part of triangular brown finger algae into 100 mesh triangular brown finger algae powder, put it and 20 parts of petroleum ether into corresponding positions of Soxhlet extractor, reflux extract at 70°C for 8h, collect the extract, evaporate the extract at 40°C to dryness, and obtain crude marine microalgae lipid; S2, dissolving the crude lipid of marine microalgae in petroleum ether equivalent to 3 times of its weight, and drying with nitrogen gas to obtain a dry product; S3, the dried product was mixed with an equal volume of a methanol solution of potassium hydroxide, saponified for 6 hours, the pH value was adjusted to 1 with a dilute hydrochloric acid solution, water was added to separate the layers, the mixture was centrifuged, and the upper oil layer was collected; S4. Mix the oil layer with an equal volume of urea-methanol solution, crystallize at -20°C for 2 hours, wash with water, and centrifuge to obtain polyunsaturated fatty acids.
[0033] Comparative Example 2 The method for extracting polyunsaturated fatty acids from marine microalgae comprises the following steps: S1. Grind 1 part of triangular brown finger algae into 100 mesh triangular brown finger algae powder, put it and 20 parts of 4-methoxythioanisole into corresponding positions of a Soxhlet extractor, reflux extract at 70° C. for 8 h, collect the extract, and evaporate the extract at 40° C. to obtain crude marine microalgae lipid; S2, dissolving the crude lipid of marine microalgae in petroleum ether equivalent to 3 times of its weight, and drying with nitrogen gas to obtain a dry product; S3, the dried product was mixed with an equal volume of a methanol solution of potassium hydroxide, saponified for 6 hours, the pH value was adjusted to 1 with a dilute hydrochloric acid solution, water was added to separate the layers, the mixture was centrifuged, and the upper oil layer was collected; S4. Mix the oil layer with an equal volume of urea-methanol solution, crystallize at -20°C for 2 hours, wash with water, and centrifuge to obtain polyunsaturated fatty acids.
[0034] Comparative Example 3 The only difference from Comparative Example 2 is that 4-methoxythioanisole is replaced by an equal amount of methanol.
[0035] Test example The mass of the marine microalgae of Examples 1 to 10 and Comparative Examples 1 to 3 and the mass of the polyunsaturated fatty acids extracted by the methods of Examples 1 to 10 and Comparative Examples 1 to 3 were measured, and the yield of the polyunsaturated fatty acids was calculated according to the following formula: Yield of polyunsaturated fatty acids = mass of polyunsaturated fatty acids ÷ mass of marine microalgae × 100%; The purity of polyunsaturated fatty acids was determined by gas chromatography, and the results are shown in Table 1.
[0036] Table 1 Test results of Examples 1 to 10 and Comparative Examples 1 to 3
[0037] Compared with Comparative Examples 1 to 3, the extracting agent in the method for extracting polyunsaturated fatty acids from marine microalgae in Examples 1 and Examples 3 to 5 is a methanol solution of 4-methoxythioanisole. As a result, the yield and purity of polyunsaturated fatty acids in Examples 1 and Examples 3 to 5 are higher than those in Comparative Examples 1 to 3, indicating that the methanol solution of 4-methoxythioanisole can improve the yield and purity of polyunsaturated fatty acids extracted from marine microalgae.
[0038] The yield and purity of the polyunsaturated fatty acids in Examples 4 to 5 are higher than those in Examples 1 and 3, indicating that the volume ratio of 4-methoxythioanisole to methanol is 4 to 7:1, which further improves the yield and purity of the polyunsaturated fatty acids extracted from marine microalgae.
[0039] The yield and purity of the polyunsaturated fatty acids in Example 6 are higher than those in Example 5, indicating that the pretreatment with copper oxide ammonia solution before grinding further improves the yield and purity of the polyunsaturated fatty acids extracted from the marine microalgae.
[0040] The yield and purity of the polyunsaturated fatty acids in Examples 7 to 10 are higher than those in Example 6, indicating that the solvent used for dissolution is a methanol solution of chloroform, which further improves the yield and purity of the polyunsaturated fatty acids extracted from marine microalgae.
[0041] The yield and purity of the polyunsaturated fatty acids in Examples 9 to 10 are higher than those in Examples 7 to 8, indicating that the volume ratio of chloroform to methanol is 7 to 8:1, which further improves the yield and purity of the polyunsaturated fatty acids extracted from marine microalgae.
[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for extracting polyunsaturated fatty acids from marine microalgae, characterized in that: The following steps are involved: S1, grinding the marine microalgae for extraction, collecting the extract, and evaporating to dryness to obtain crude marine microalgae lipids; S2, dissolving the crude lipid of marine microalgae, and drying with nitrogen to obtain a dry product; S3, mixing the dried product with a methanol solution of potassium hydroxide for saponification, adjusting the pH value to 1-2, adding water and layering, centrifuging, and collecting the upper oil layer; S4, mixing the oil layer with a methanol solution of urea, crystallizing, washing with water, and centrifuging to obtain polyunsaturated fatty acids; During the extraction in S1, the extractant includes a compound containing a methylthio group and methanol.
2. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 1, characterized in that: The compound containing a methylthio group is 4-methoxythioanisole.
3. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 2, characterized in that: The volume ratio of the 4-methoxythioanisole to methanol is 3-9:
1.
4. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 3, characterized in that: The volume ratio of the 4-methoxythioanisole to methanol is 4-7:
1.
5. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 1, characterized in that: The pretreatment is performed before grinding, and the pretreatment specifically comprises: soaking the marine microalgae in a copper oxide ammonia solution, filtering, washing with water, and drying.
6. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 5, characterized in that: The mass ratio of the marine microalgae to the copper oxide ammonia solution is 1-5:
30.
7. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 1, characterized in that: When dissolving in S2, the solvent used includes chloroform and methanol in a volume ratio of 1 to 9:
1.
8. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 7, characterized in that: The mass ratio of the marine microalgae crude lipid to the solvent is 1:3-5.
9. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 1, characterized in that: The marine microalgae include one or more of the group consisting of triangular brown algae, purple algae, and halogenated microgreen algae.
10. The method for extracting polyunsaturated fatty acids from marine microalgae according to claim 1, characterized in that: The mass ratio of the marine microalgae to the extractant is 1:20-30.