Extracting agent and method for extracting microalgae pigment

Abstract

The invention provides an extracting agent and an extracting method of microalgae pigment. The extracting agent comprises 30-80% of polyol polymer or glucan, 1-5% of ionic liquid or eutectic solvent and water. And putting the algae powder into an extracting agent, and preserving heat to obtain the microalgae pigment. The method is a one-step method, the pigment is extracted from the microalgae powder by using an ionic liquid-polymer aqueous solution, an organic solvent is not used, a cell wall breaking step is reduced, and green solid-liquid extraction is realized.

Description

Technical Field

[0001] The invention relates to the field of microalgae biotechnology, and in particular to an extractant and an extraction method for extracting microalgae pigments. Background Art

[0002] Microalgae is a single-cell organism that can perform photosynthesis. Microalgae cells contain abundant bioactive substances and are an important source of food and health products. These active substances include proteins, polysaccharides, oils and pigments. Pigments in microalgae include chlorophyll, carotenoids, salinophyton, etc. Pigments can be extracted by organic solvent extraction, ultrasonic or microwave-assisted extraction, supercritical extraction, etc.

[0003] At present, the extraction of microalgae pigments still faces the following challenges: 1) The cell wall of microalgae is tough and has a complex and diverse structure, which requires pretreatment to achieve a high extraction efficiency, but this will increase the separation cost and complexity; 2) The current extraction of microalgae pigments is mainly based on organic solvent extraction, especially methanol, which has certain harm to the environment, and it is necessary to develop green solvents to extract microalgae pigments.

[0004] Ionic liquids are composed of anions and cations, and have low vapor pressure and high solubility at room temperature. Compared with organic solvents, they have better chemical and thermal stability and are typical green solvents. The physical properties of ionic liquids (polarity, hydrophobicity and viscosity) can be controlled by the combination of different cations and anions, so they are widely used in various fields such as organic synthesis, catalytic reactions, electrochemistry, material chemistry, separation technology, environmental science, biomass energy, etc., showing good application prospects. In addition, ionic liquids are also reproducible. Summary of the invention

[0005] In view of the above problems, the present invention provides an extractant and an extraction method for extracting microalgae pigments, which can realize green extraction of microalgae pigments. The present invention is a one-step method, which uses an ionic liquid-polymer aqueous solution to extract pigments from microalgae powder, does not use organic solvents, reduces the cell wall breaking step, optimizes the ionic liquid (or eutectic solvent) and polymer types and ratios, water bath temperature and time, solid-liquid ratio and other conditions, and realizes green solid-liquid extraction.

[0006] In order to achieve the above object, the technical solution provided by the present invention is: An extractant for microalgae pigments, comprising the following components by weight: Polyol polymer or dextran 30~80%; Ionic liquid or eutectic solvent 1~5%; The balance is water.

[0007] Preferably, the polyol polymer is polyethylene glycol or polypropylene glycol.

[0008] Preferably, the molecular weight of the polyol polymer or the dextran is 400-8000.

[0009] Preferably, the ionic liquid is an imidazole ionic liquid or a choline ionic liquid, or a mixture of the two. More preferably, the ionic liquid is a mixture of an imidazole ionic liquid and a choline ionic liquid, wherein the weight ratio of the imidazole ionic liquid to the choline ionic liquid is 0.05 to 1:1.

[0010] Preferably, the eutectic solvent is a eutectic solvent synthesized from an imidazole ionic liquid or a choline ionic liquid and an acid or an alcohol. More preferably, the molar ratio of the imidazole ionic liquid or the choline ionic liquid to the acid or the alcohol in the eutectic solvent is 1:1-8.

[0011] Preferably, the microalgae pigment is lutein or carotenoid.

[0012] The second object of the present invention is to provide a method for extracting microalgae pigments, comprising the following steps: The algae powder of microalgae is placed in the above extractant and kept warm to obtain the microalgae pigment.

[0013] Preferably, the insulation temperature is 35-55°C.

[0014] Preferably, the insulation time is 30 to 90 minutes.

[0015] Preferably, the mass ratio of the algae powder to the extractant is 1:300~700.

[0016] Preferably, the algae powder is fresh algae powder or algae residue that has been extracted.

[0017] The beneficial effects of the present invention are: (1) The extractant and extraction method provided by the present invention are suitable for extracting microalgae pigments from algae powder with a high extraction rate.

[0018] (2) The present invention can directly extract algae powder without pre-treatment such as cell wall disruption.

[0019] (3) The extractant of the present invention does not contain any organic solvent, but only contains polyol polymers, ionic liquids and their eutectic solvents, and is environmentally friendly.

[0020] (4) The extraction method of the present invention is simple, easy to operate, low in cost and has significant effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a comparison chart of the extraction efficiency in Example 1 of the present invention.

[0022] Figure 2It is a comparison chart of the extraction efficiency in Example 2 of the present invention.

[0023] Figure 3 3 is a comparison chart of the extraction efficiency in Example 3 of the present invention.

[0024] Figure 4 It is a comparison chart of the extraction efficiency in Example 4 of the present invention. DETAILED DESCRIPTION Example 1

[0025] (1) Preparation of extractant: Take appropriate amounts of choline chloride (ChCl), PPG400 and water and add them to a 10 ml centrifuge tube to prepare a single-phase extraction solvent of 4.22 g 1.43% ChCl, 69% PPG400 and the balance water.

[0026] (2) Extraction of microalgae pigments: Take 10 mg of Nannochloropsis algae powder and put it into 4.22 g of the prepared extractant, vortex for 2 min, water bath at 47 °C for 60 min, take out and vortex for 2 min, centrifuge at 3000 r for 10 min. Record the volume of the supernatant, take 200 ml of the supernatant and observe the OD at 480 nm in an ELISA instrument, and use the formula to calculate the carotenoid content.

[0027] After removing the supernatant, take the algae residue, repeat the above operation to perform the second extraction and calculate the carotenoid content.

[0028] Take 10 mg of Nannochloropsis algae powder and put it into a 2 ml centrifuge tube. Add methanol to the 2 ml mark. Vortex for 5 min, place in a 55°C water bath for 30 min, and centrifuge at 6000 r for 5 min. Take 200 ul of supernatant and observe the OD at 480 nm in an ELISA reader. Use the formula to calculate the carotenoid content and set it as the 100% control group.

[0029] The results are as follows Figure 1 As shown, by using the method of the present invention, the extraction efficiency of carotenoids in the first extraction is 94.19%, and the efficiency of the second extraction is 103.89%. Example 2

[0030] (1) Preparation of extractant: A deep eutectic solvent (DES) of ChCl:1,4-butanediol with a molar ratio of 1:3 was prepared.

[0031] Take appropriate amounts of DES, PPG400 and water and add them to a 10 ml centrifuge tube to prepare an extractant of 5.50 g of 69.5% PPG400, 2% DES and the balance of water.

[0032] (2) Extraction of microalgae pigments: Take 10 mg of Nannochloropsis algae powder and add it to 5.50 g of the prepared extractant in a centrifuge tube, vortex for 2 min, place in a 55°C water bath for 1 h, and centrifuge at 3000r for 10 min. Record the volume of the supernatant, take 200 ml of the supernatant and observe the OD at 480nm in an ELISA instrument, and calculate the carotenoid content using the carotenoid formula.

[0033] The results are as follows Figure 2 As shown, the best extraction efficiency is 102.97%. Example 3

[0034] (1) Preparation of extractant: The extractant was prepared by mixing 1 g [BMIM]Br, 2 g ChCl:ethylene glycol with a molar ratio of 1:2, 1.8 g PPG400, and 2 g water.

[0035] (2) Extraction of microalgae pigments: Take 1 mg of algae powder and put it into a centrifuge tube, add the above extractant, incubate in a 65℃ water bath for 1 hour, and centrifuge at 3000 r for 10 minutes. Record the volume of the supernatant, take 200 ml of the supernatant and observe the OD at 445, 652, and 665 nm in an ELISA reader, and calculate the lutein content using the three-wavelength method.

[0036] The lutein in Chlorella powder was extracted with 2 ml of methanol as a control.

[0037] The results are as follows Figure 3 As shown, the extraction efficiency of the method proposed by the present invention is 86.62% compared with that of methanol extraction. Example 4

[0038] (1) Preparation of extractant: The extractant was prepared by mixing 1.25 g [BMIM]Br, 2.6 g PPG400 and 1.15 g water.

[0039] (2) Extraction of microalgae pigments: Take 2 mg of algae powder and put it into a centrifuge tube, add the above extractant, incubate in a 65℃ water bath for 1 hour, and centrifuge at 3000 r for 10 minutes. Record the volume of the supernatant, take 200 ml of the supernatant and observe the OD at 445, 652, and 665 nm in an ELISA reader, and calculate the lutein content using the three-wavelength method.

[0040] The lutein in Chlorella powder was extracted with 2 ml of methanol as a control.

[0041] The results are as follows Figure 4 As shown, the extraction efficiency of the method proposed by the present invention is 93.66% compared with methanol extraction.

Claims

1. An extractant for microalgae pigments, characterized in that: The composition includes the following weight contents: Polyol polymer or dextran 30~80%; Ionic liquid or eutectic solvent 1~5%; The balance is water.

2. The extractant according to claim 1, characterized in that The polyol polymer is polyethylene glycol or polypropylene glycol.

3. The extractant according to claim 1, characterized in that The molecular weight of the polyol polymer or the dextran is 400-8000.

4. The extractant according to claim 1, characterized in that The ionic liquid is one or a mixture of imidazole ionic liquid or choline ionic liquid; more preferably, the ionic liquid is a mixture of imidazole ionic liquid and choline ionic liquid, wherein the weight ratio of the imidazole ionic liquid to the choline ionic liquid is 0.05 to 1:1; The eutectic solvent is a eutectic solvent synthesized from an imidazole ionic liquid or a choline ionic liquid and an acid or an alcohol; more preferably, the molar ratio of the imidazole ionic liquid or the choline ionic liquid to the acid or the alcohol in the eutectic solvent is 1:1-8.

5. The extractant according to claim 1, characterized in that The microalgae pigment is lutein or carotenoid.

6. A method for extracting microalgae pigments, characterized in that: The steps include: The algae powder of microalgae is placed in the extractant according to any one of claims 1 to 4 and kept warm to obtain the microalgae pigment.

7. The extraction method according to claim 6, characterized in that The insulation temperature is 35-55°C.

8. The extraction method according to claim 6, characterized in that The insulation time is 30 to 90 minutes.

9. The extraction method according to claim 6, characterized in that The mass ratio of the algae powder to the extractant is 1:300-700.

10. The extraction method according to claim 6, characterized in that The algae powder is fresh algae powder or algae residue that has been extracted.

Images