Plant-derived surfactant and preparation method thereof

Abstract

The invention relates to the field of surfactants, and particularly provides a plant-derived surfactant and a preparation method thereof. The preparation method of the plant-derived surfactant comprises the following steps: dispersing microcrystalline cellulose in a solvent in an inert atmosphere, adding fatty alcohol, and performing stirring treatment while performing ultrasonic treatment to obtain colloid; mixing the magnetic carrier with a transglycosylation enzyme solution, and carrying out adsorption reaction to obtain an immobilized enzyme catalyst; and mixing the colloid and the immobilized enzyme catalyst, adjusting the pH value to 5-7, and sequentially carrying out constant-temperature stirring treatment and filtering treatment to obtain the plant-derived surfactant. The immobilized transglycosylation enzyme is used as a catalyst, and high-selectivity glycosylation reaction of cellulose and fatty alcohol can be achieved. The method is mild in enzyme catalysis condition, strong in directivity, good in product selectivity and high in controllability, common polymers and thermal degradation byproducts in the acid catalysis process are avoided, and the yield and purity of the target alkyl glycoside are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of surfactants, and in particular to a plant-derived surfactant and a preparation method thereof. Background Art

[0002] Alkyl polyglycosides (APGs) are a new class of surfactants developed in the late 1980s and early 1990s. They combine many of the advantages of both nonionic and anionic surfactants, offering low surface tension, high activity, strong detergency, and rich, smooth, and stable foam. They also exhibit excellent compatibility with other surfactants, exhibit minimal skin and eye irritation, are biodegradable, non-toxic, have excellent compatibility, and are environmentally friendly. They are widely used in detergents, industrial emulsifiers, cosmetics, food, and pharmaceutical industries. Due to their synthetic raw materials and performance characteristics, they are hailed as a new generation of mild, "green" surfactants, and are the only surfactant, after LAS, AES, and AEO, to truly be considered "world-class."

[0003] Chinese patent application CN1077397A discloses a method for preparing an alkyl glycoside surfactant. This involves a condensation reaction between glucose or a hydrolyzable monosaccharide and a fatty alcohol in the presence of a strong acid, requiring high-temperature heating and producing a large amount of byproducts and waste acid. Chinese patent application CN102250160B discloses a method for preparing an alkyl glycoside using microwave-ultrasonic synergistic catalysis. This method incorporates microwave-ultrasonic enhancement and requires preheating the glucose and fatty alcohol, vacuum extraction, and then adding an acid catalyst. Both methods rely on strong acid catalysis and high temperatures for synthesizing alkyl glycosides, resulting in high corrosiveness, high energy consumption, and the production of byproducts.

[0004] Therefore, there is an urgent need for a preparation method that is mild in process and can effectively avoid the side reactions caused by strong acid corrosion and high-temperature cracking. Summary of the Invention

[0005] The present invention provides a plant-derived surfactant and a preparation method thereof. Using immobilized transglycosylase as a catalyst, the surfactant can achieve highly selective glycosidation of cellulose with fatty alcohols. The enzyme catalysis is mild, highly directional, and produces high product selectivity and controllability, avoiding the formation of polymers and thermal degradation byproducts commonly seen in acid-catalyzed processes. This improves the yield and purity of the target alkyl glycoside. Furthermore, by immobilizing the transglycosylase on a magnetic nanocarrier, the catalyst can be rapidly separated and recovered using a magnetic field, significantly reducing enzyme consumption and production costs.

[0006] The present invention provides a method for preparing a plant-derived surfactant. The plant-derived surfactant comprises the following steps: S100: dispersing microcrystalline cellulose in a solvent under an inert atmosphere, adding fatty alcohol, and stirring while ultrasonically treating to obtain a colloid; S200: mixing a magnetic carrier with a transglycosylase solution, performing an adsorption reaction to obtain an immobilized enzyme catalyst; S300: mixing the colloid and the immobilized enzyme catalyst, adjusting the pH to 5-7, and sequentially performing constant temperature stirring and filtering to obtain the plant-derived surfactant.

[0007] In any of the above technical solutions, in step S100, the inert atmosphere includes at least one of nitrogen and argon; and / or the fatty alcohol has a carbon chain length of C 12 -C 18 and / or the solvent includes glycerol; and / or the mass ratio of microcrystalline cellulose: solvent: fatty alcohol is 1: (4-6): (1-3); and / or the power of ultrasonic treatment is 500-600W, and the time is 30-60min.

[0008] In any of the above technical solutions, in step S100, the fatty alcohol includes at least one of lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol.

[0009] In any of the above technical solutions, step S200 specifically includes: S210: placing magnetic nanoparticles in an ethanol solution, adding 3-aminopropyltriethoxysilane, and ultrasonically treating under magnetic stirring to obtain a first mixed solution; S220: adjusting the pH value of the first mixed solution to a range of 4-6, heating it to 70-90°C, reflux stirring for 3-5 hours, washing and precipitating it in sequence, and vacuum drying it to obtain a magnetic carrier; S230: dispersing the magnetic carrier in phosphate buffer, adding a transglycosylase solution while ultrasonically treating it, and performing magnetic stirring treatment, magnetic separation treatment, and washing and precipitation treatment in sequence to obtain an immobilized enzyme catalyst.

[0010] In any of the above technical solutions, in step S210, the ultrasonic treatment time is 5-15 min and the power is 200-400 W; and / or in step S210, the mass ratio of magnetic nanoparticles to 3-aminopropyltriethoxysilane is 1:(0.5-1.2); and / or in step S210, the speed of magnetic stirring is 400-600 rpm; and / or in step S220, the vacuum drying temperature is 50-70°C and the time is 10-14 h; and / or in step S230, the stirring treatment temperature is 50-70°C and the time is 0.5-2 h; and / or in step S230, the pH value of the phosphate buffer is 5-7; and / or in step S230, the concentration of the transglycosylase solution is 10-50 mg / mL.

[0011] In any of the above technical solutions, in step S300, the mass ratio of the colloid to the immobilized enzyme catalyst is (8-12):1; and / or the constant temperature stirring treatment is at 55-68°C for 4-6 hours; and / or the filtration treatment is performed using a 0.20-0.25 μm microporous membrane.

[0012] In any of the above technical solutions, before step S100, the method further includes: S000, performing acid hydrolysis pretreatment on the microcrystalline cellulose to control the degree of polymerization of the microcrystalline cellulose to be 50-100.

[0013] In any of the above technical solutions, the acid hydrolysis conditions are: 0.5-1 mol / L sulfuric acid, 60-80° C., 1-2 h.

[0014] In any of the above technical solutions, the plant-derived surfactant is cellulose alkyl glycoside, which has the following molecular structure formula: (C6H 10 O5) n -OR; where R is the length of C 12 -C 18 A straight chain or branched alkyl group, n is a degree of polymerization between 10-30.

[0015] The present invention also provides a plant-derived surfactant prepared by any of the above-mentioned preparation methods.

[0016] After adopting the technical solution of the present invention, the technical effects that can be achieved are as follows:

[0017] 1. Through the directional catalysis of immobilized transglycosylase, a highly selective glycosidation reaction between cellulose and fatty alcohols was achieved, avoiding the side reactions of traditional acid catalysis, and greatly improving the purity and yield of the product;

[0018] 2. The enzyme-catalyzed reaction conditions are mild, and no strong acid or high temperature conditions are required, which reduces the corrosion requirements of equipment, reduces energy consumption, and complies with green chemistry standards;

[0019] 3. Immobilized enzymes can be quickly separated by magnetic carriers, which reduces catalyst loss and significantly reduces production costs.

[0020] 4. By regulating the degree of polymerization and fatty alcohol chain length of acid hydrolysis pretreatment, the HLB value, surface tension and foam stability of the product can be adjusted to meet the application requirements of detergents, cosmetics, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings to be used in describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0022] Figure 1 This is the pNP concentration-absorbance standard curve of Example 1 at a wavelength of 405 nm. DETAILED DESCRIPTION

[0023] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below.

[0026] Alkyl polyglycosides (APGs) are a new class of surfactants developed in the late 1980s and early 1990s. They combine many of the advantages of both nonionic and anionic surfactants, offering low surface tension, high activity, strong detergency, and rich, smooth, and stable foam. They also exhibit excellent compatibility with other surfactants, exhibit minimal skin and eye irritation, are biodegradable, non-toxic, have excellent compatibility, and are environmentally friendly. They are widely used in detergents, industrial emulsifiers, cosmetics, food, and pharmaceutical industries. Due to their synthetic raw materials and performance characteristics, they are hailed as a new generation of mild, "green" surfactants, recognized as truly "world-class" surfactants after LAS, AES, and AEO.

[0027] Chinese patent application CN1077397A discloses a method for preparing an alkyl glycoside surfactant. This method involves a condensation reaction between glucose or a hydrolyzable monosaccharide and a fatty alcohol in the presence of a strong acid, requiring high-temperature heating and producing a large amount of byproducts and waste acid. Chinese patent application CN102250160B discloses a method for preparing an alkyl glycoside using microwave-ultrasonic synergistic catalysis. This method incorporates microwave-ultrasonic enhancement and requires preheating the glucose and fatty alcohol, vacuum extraction, and then the addition of an acid catalyst. Both methods rely on strong acids and high temperatures, and suffer from drawbacks such as high corrosiveness, high energy consumption, and a high concentration of impurities.

[0028] Therefore, this example provides a plant-derived surfactant and its preparation method, using an immobilized transglycosylase as a catalyst to achieve highly selective glycosidation of cellulose with fatty alcohols. This method, characterized by mild conditions, high selectivity, and high controllability, effectively inhibits polymers and thermal degradation byproducts, significantly improving target yield and purity. Furthermore, by immobilizing the enzyme on a magnetic nanocarrier, rapid magnetic separation and reuse of the catalyst are achieved, significantly reducing enzyme consumption and production costs.

[0029] The present invention provides a method for preparing a plant-derived surfactant, which comprises the following steps:

[0030] S100: Under an inert atmosphere, microcrystalline cellulose is dispersed in a solvent, and a fatty alcohol is added, and the mixture is stirred while being ultrasonically treated to obtain a colloid;

[0031] S200: mixing the magnetic carrier with the transglycosylase solution to perform an adsorption reaction to obtain an immobilized enzyme catalyst;

[0032] S300: mixing the colloid and the immobilized enzyme catalyst, adjusting the pH to 6.5, and sequentially performing constant temperature stirring treatment and filtering treatment to obtain a plant-derived surfactant.

[0033] Preferably, the raw materials selected in this application are green and renewable, using microcrystalline cellulose and C 12 -C 18 Fatty alcohols are used as raw materials, all of which are derived from natural plants or biomass, are renewable and non-toxic, and use cellulose to replace traditional monosaccharide raw materials, which is in line with the concept of green chemistry and reduces dependence on petrochemical resources.

[0034] Furthermore, in step S100, during the ultrasonic dispersion process under an inert atmosphere, C 12 -C 18Long chain fatty alcohols, such as lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol, combine with the cellulose end to construct a non-ionic amphiphilic structure with both hydrophilic and hydrophobic properties, providing a stable "R" segment for the surfactant molecule; different chain lengths correspond to different HLB values, for example, HLB3-6 is suitable for oil-in-water, and HLB8-18 is suitable for oil-in-water. Short-chain lauryl alcohol has a higher HLB value, which is conducive to the formation of oil-in-water emulsions, while long-chain cetyl alcohol and stearyl alcohol have a lower HLB value and are more suitable for oil-in-water systems to meet the needs of diversified formulations; the lauryl alcohol segment can significantly improve foam generation and stability The stearyl alcohol chain enhances wettability and diffusion properties, promoting uniform application on skin or hair. Myristyl alcohol not only acts as a hydrophobic chain but also thickens and smoothes the formulation, resulting in a moderate viscosity, a smooth feel, and good thixotropy under shear. Cetyl alcohol and stearyl alcohol, due to their low irritation and excellent skin compatibility, can enhance the mildness of cosmetics and reduce the risk of stratification and precipitation. Ultrasonic treatment promotes the formation of a stable colloid between fatty alcohols and cellulose, uniformly dispersing and expanding the reaction interface, thereby enhancing enzyme catalysis efficiency and increasing glycosidation conversion rate. In addition, fatty alcohols of different chain lengths can be used alone or mixed in proportion, and the foam properties, consistency, and emulsification type can be adjusted by adjusting the HLB value.

[0035] Furthermore, cellulose has extremely low solubility in fatty alcohols and is prone to agglomeration, resulting in slow reaction rate and low conversion efficiency. Ultrasonic dispersion of the mixture under an inert atmosphere, such as nitrogen or argon, allows the cellulose to form a stable colloid, significantly improving the dispersion of the raw materials in the reaction system, reducing agglomeration, and increasing the reaction interface area, thereby accelerating the enzyme-catalyzed reaction rate. In addition, nitrogen and argon prevent fatty alcohol or cellulose from being oxidized and inactivated during the ultrasonic and heating process, thereby maintaining the stability of the system. The ultrasonic treatment power is 500-600W and the time is 30-60min. Ultrasonic treatment destroys the crystalline region of microcrystalline cellulose, increases the specific surface area, and forms a stable colloid with cellulose and fatty alcohol through vibration and shear force, thereby improving dispersibility and reaction interface. The use of glycerol not only provides a hydrophilic environment to promote cellulose deagglomeration, but also dissolves fatty alcohol at the same time, facilitating homogeneous pre-assembly. The mass ratio of microcrystalline cellulose: solvent: fatty alcohol is 1: (4-6): (1-3). This ratio ensures moderate dilution of the solid and liquid to reduce viscosity, which is beneficial for ultrasound and stirring, while also ensuring that the fatty alcohol is excessive but not phase-separated, allowing it to fully contact the cellulose ends without forming an independent phase that hinders enzyme catalysis. At the same time, this ratio can also take into account product performance: the combination of short and long chains can accurately control the HLB value by adjusting the ratio of fatty alcohol to meet the needs of oil-in-water or water-in-oil emulsion systems. The mass ratio of the water phase is in the range of 4-6, which not only ensures the efficiency of ultrasonic dispersion, but also avoids excessive solvent that leads to increased energy consumption and separation difficulty.

[0036] It is worth noting that microcrystalline cellulose is pretreated by acid hydrolysis to control the degree of polymerization of microcrystalline cellulose to 50-100; the acid hydrolysis conditions are: 0.5-1 mol / L sulfuric acid, 60-80℃ treatment for 1-2h; by selectively breaking the β-1,4-glycosidic bonds in the cellulose molecules, its degree of polymerization is significantly reduced, and the long-chain cellulose is degraded into short-chain oligosaccharides. At the same time, the amorphous region is preferentially removed and the crystalline structure is retained to form microcrystalline cellulose with a high specific surface area and porous structure. This process not only exposes more terminal hydroxyl groups to enhance the reaction activity, but also improves the purity of the raw material by removing hemicellulose and lignin impurities; in the subsequent enzyme-catalyzed synthesis, the short-chain oligosaccharides pretreated by acid hydrolysis can be precisely cleaved by transglycosylase and transferred to fatty alcohols, generating a structural formula of (C6H 10 O5) n -OR cellulose alkyl glycoside, in which the oligosaccharide chain length n=10-30 is precisely regulated by acid hydrolysis conditions, which directly affects the HLB value and surface activity of the product, thereby achieving a directional association from raw material structure modification to product function design.

[0037] In addition, although the acid hydrolysis pretreatment involved in this embodiment is only a modification step of the cellulose raw material, the residual acid is completely removed by subsequent neutralization and washing to ensure that the subsequent enzyme catalytic reaction is carried out under acid-free conditions.

[0038] Preferably, step S200 specifically includes:

[0039] S210: placing the magnetic nanoparticles in an ethanol solution, adding 3-aminopropyltriethoxysilane, and ultrasonically treating the solution under magnetic stirring to obtain a first mixed solution;

[0040] S220: adjusting the pH value of the first mixed solution to a range of 4-6, heating to 70-90° C., refluxing with stirring for 3-5 hours, washing and precipitating, and vacuum drying to obtain the magnetic carrier;

[0041] S230: dispersing the magnetic carrier in phosphate buffer, adding transglycosylase solution while ultrasonically treating, and sequentially performing magnetic stirring treatment, magnetic separation treatment, washing and precipitation treatment to obtain the immobilized enzyme catalyst.

[0042] Furthermore, step S200 achieves efficient immobilization of transglycosylase through steps S210-S230: first, a functionalized carrier is constructed by coupling Fe3O4 or Fe3O4@SiO2 nanoparticles with 3-aminopropyltriethoxysilane (APTES); second, ultrasound and magnetic stirring are combined to promote uniform dispersion of the carrier and enzyme-carrier contact; finally, magnetic separation and vacuum drying are used to ensure the carrier pore structure and enzyme activity. Magnetic nanoparticles have an ultra-high specific surface area and can provide more enzyme binding sites, thereby improving catalytic activity and substrate conversion rate. Magnetic nanoparticles include Fe3O4@SiO2 or Fe3O4; APTES forms a stable silane monolayer on the particle surface, providing -NH2 functional groups for the enzyme molecules, achieving covalent or ionic adsorption, and enhancing the enzyme-carrier binding strength and initial activity; ultrasonic treatment at 200-400W for 5-15min improves the contact between the enzyme and the carrier surface through the cavitation effect, significantly improving the immobilization efficiency and enzyme activity retention rate; magnetic stirring at 400-600rpm, synergistically with ultrasonic treatment, can reduce nanoparticle agglomeration, make the hydrolysis and condensation of APTES more thorough, form a uniform functional layer, and further improve the uniformity of enzyme loading. The immobilized enzyme maintains a more stable conformation at 50-70°C or at a pH of 5-7, significantly reducing its thermal inactivation rate and extending its lifespan. Magnetic separation allows for rapid recovery without the need for energy-intensive centrifugation, allowing for repeated use while maintaining activity and reducing costs. At a mass ratio of 1:0.5-1.2 for Fe₃O₄@SiO₂ or Fe₃O₄ to APTES, APTES forms a monolayer, increasing hydrophilicity and reducing aggregation, ensuring magnetic responsiveness. Vacuum drying at 50-70°C for 10-14 hours removes the solvent under low pressure and low temperature, maintaining the integrity of the carrier pores and surface functionalization layer. Magnetic separation in S230 rapidly separates the immobilized enzyme from the reaction mixture, requiring only an external magnetic field to sediment the carrier, eliminating traditional filtration or centrifugation, improving production efficiency and reducing energy consumption. The process is performed in phosphate buffer, ensuring an optimal binding environment for enzyme activity. The modular design of coupling, drying, and enzyme adsorption facilitates integration with existing reactors, ultrasonicators, and magnetic separation units, enabling continuous production.

[0043] Furthermore, Fe3O4@SiO2 was prepared by the sol-gel method: Fe3O4 nanoparticles were dispersed in ethanol, ethyl orthosilicate and ammonia were added, reacted at 40-70°C for 5-7 hours, centrifuged, washed and dried to obtain Fe3O4@SiO2.

[0044] Preferably, in step S300, the mass ratio of colloid to immobilized enzyme is (8-12):1. A higher amount of colloid can ensure that there are sufficient substrate molecules around the enzyme, reduce enzyme idling, and improve the conversion rate of a single reaction. Too low an enzyme loading will lead to an excess of substrate and limit enzyme activity. At this ratio, the substrate-enzyme interface achieves optimal coverage, taking into account both economy and catalytic efficiency. The appropriate colloid concentration helps maintain the viscosity of the system within a controllable range, avoids diffusion restriction caused by excessive reaction density, and ensures uniform stirring. Transglycosylase is most active in a neutral to slightly acidic range, i.e., pH 6.0-7.0. The charge distribution of the enzyme molecule is moderate, the active site conformation remains stable, and irreversible inactivation caused by extreme pH is reduced. At a temperature of 55-68°C, molecular thermal motion can be significantly accelerated, increasing the frequency of enzyme-substrate collisions, thereby improving the catalytic rate; at a rotation speed of 400-600rpm, the system temperature is ensured to be uniform, while avoiding local overheating or cold spots, which is conducive to continuous and efficient reactions. Mild high-temperature treatment can inhibit microbial contamination and non-enzymatic degradation reactions, thereby improving the yield and purity of the target product.

[0045] Furthermore, the production of the plant-derived surfactant in this embodiment can be represented by the following concise chemical equation:

[0046]

[0047] Among them, [C6H7O2(OH)3] n is a cellulose polymer unit, and n is usually between 10 and 30;

[0048] R-OH is C 12 -C 18 fatty alcohols;

[0049] Product [C6H7O2(OH)3] n -OR is cellulose alkyl glycoside.

[0050] The plant-derived surfactant of this embodiment catalyzes the formation of glycosidic bonds between cellulose and fatty alcohols through transglycosylase, transfers glucose units to fatty alcohols, generates alkyl glycosides and dehydrates; the reaction is reversible, water is the equilibrium product, and constant temperature stirring and ultrasonic assistance promote the separation of the aqueous phase, which is conducive to movement toward the product; the immobilized enzyme maintains high activity and reduces inactivation at neutral and slightly acidic temperatures and 55-68°C, and can be recovered and reused by magnetic separation, simplifying the process and reducing costs. This structure combines the hydrophilic polyhydroxy properties of cellulose with the hydrophobic properties of alkyl chains, and therefore exhibits excellent nonionic surfactant properties.

[0051] In general, this embodiment uses immobilized transglycosylase as a catalyst to achieve highly selective glycosidation reaction of cellulose and fatty alcohols. The enzyme catalysis conditions are mild, the directionality is strong, the product selectivity is good, the controllability is high, and the common polymers and thermal degradation byproducts in the acid catalysis process are avoided, thereby improving the yield and purity of the target alkyl glycoside; and the transglycosylase is immobilized by a magnetic nanocarrier, and the catalyst can be quickly separated and recovered by a magnetic field. Unlike traditional homogeneous catalysts, the magnetic immobilized enzyme catalyst can be quickly recovered and reused after the reaction, which greatly reduces enzyme consumption and production costs; finally, the entire synthesis process is carried out under relatively mild conditions, without the need for excessively high temperatures or vacuum extraction, and also avoids subsequent energy-consuming steps such as high-temperature distillation and dealcoholization. Therefore, this application overcomes the high energy consumption problem in traditional processes and has better environmental friendliness and economy.

[0052] Example 1

[0053] This embodiment provides a plant-derived surfactant and a preparation method thereof, and its molecular structure is as follows:

[0054] (C6H 10 O5) 12 -OC 18 H 37 ;

[0055] The preparation method comprises the following steps:

[0056] S000, pre-treating microcrystalline cellulose by acid hydrolysis in 0.5 mol / L sulfuric acid at 80°C for 1 hour to control the degree of polymerization of microcrystalline cellulose to 50, separating by centrifugation after acid hydrolysis, washing with deionized water until neutral, and drying for later use;

[0057] S100: Under nitrogen atmosphere, 1 g of microcrystalline cellulose with a degree of polymerization of 50 was dispersed in 5 g of glycerol, and 2 g of lauryl alcohol was added. The mixture was ultrasonically treated at 600 W for 30 min while stirring to obtain a colloid;

[0058] S211: Fe3O4 nanoparticles were dispersed in ethanol, and ethyl orthosilicate and ammonia were added. The mixture was reacted at 40°C for 7 hours, and then centrifuged, washed, and dried to obtain Fe3O4@SiO2.

[0059] S210: 1 g of Fe3O4@SiO2 was placed in an ethanol solution, 1.2 g of APTES was added, and the mixture was ultrasonically treated at 400 W for 5 min under magnetic stirring at 600 rpm to obtain a first mixed solution;

[0060] S220: adjusting the pH value of the first mixed solution to 6, refluxing at 90° C. with stirring for 3 h, washing the precipitate, and vacuum drying at 70° C. for 10 h to obtain a magnetic carrier;

[0061] S230: dispersing the magnetic carrier in a phosphate buffer solution with a pH of 7, adding a transglycosylase solution with a concentration of 10 mg / mL and an enzyme activity of 300 U / mg while ultrasonicating, treating the solution under magnetic stirring at 70° C. for 0.5 h, performing magnetic separation, and then washing and precipitating the solution to obtain an immobilized enzyme catalyst;

[0062] S300: 5 g of colloid was mixed with 1 g of immobilized enzyme catalyst, the pH was adjusted to 7, the mixture was stirred at a constant temperature of 68° C. for 4 h, and filtered through a 0.25 μm microporous membrane to obtain a plant-derived surfactant.

[0063] Example 2

[0064] This embodiment provides a plant-derived surfactant and a preparation method thereof, and its molecular structure is as follows:

[0065] (C6H 10 O5) 25 -OC 14 H 29 ;

[0066] The preparation method comprises the following steps:

[0067] S000, pre-treating microcrystalline cellulose by acid hydrolysis in 1 mol / L sulfuric acid at 60°C for 2 h, controlling the degree of polymerization of microcrystalline cellulose to 100, separating by centrifugation after acid hydrolysis, washing with deionized water until neutral, and drying for later use;

[0068] S100: Under argon atmosphere, 1 g of microcrystalline cellulose with a degree of polymerization of 100 was dispersed in 4 g of glycerol, and 1 g of myristyl alcohol was added. The mixture was ultrasonically treated at 500 W for 60 min while stirring to obtain a colloid;

[0069] S210: 1 g of Fe3O4 was placed in an ethanol solution, 0.5 g of APTES was added, and ultrasonic treatment was performed at 200 W for 15 min under magnetic stirring at 400 rpm to obtain a first mixed solution;

[0070] S220: adjusting the pH value of the first mixed solution to 4, stirring under reflux at 70° C. for 5 h, washing the precipitate, and vacuum drying at 50° C. for 14 h to obtain a magnetic carrier;

[0071] S230: dispersing the magnetic carrier in a phosphate buffer solution with a pH of 5, adding a transglycosylase solution with a concentration of 50 mg / mL and an enzyme activity of 200 U / mg while ultrasonicating, treating with magnetic stirring at 50° C. for 2 h, performing magnetic separation treatment, and then washing and precipitating to obtain an immobilized enzyme catalyst;

[0072] S300: 8 g of colloid was mixed with 1 g of immobilized enzyme catalyst, the pH was adjusted to 5, the mixture was stirred at a constant temperature of 55° C. for 6 h, and filtered through a 0.20 μm microporous membrane to obtain a plant-derived surfactant.

[0073] Example 3

[0074] This embodiment provides a plant-derived surfactant and a preparation method thereof, and its molecular structure is as follows:

[0075] (C6H 10 O5) 20 -OC 12 H 25 ;

[0076] The preparation method comprises the following steps:

[0077] S000, pre-treating microcrystalline cellulose by acid hydrolysis in 0.8 mol / L sulfuric acid at 70°C for 1.5 h to control the degree of polymerization of microcrystalline cellulose to 75, centrifugally separating after acid hydrolysis, washing with deionized water to neutrality, and drying for later use;

[0078] S100: Under nitrogen atmosphere, 1 g of microcrystalline cellulose with a degree of polymerization of 75 was dispersed in 6 g of glycerol, and 3 g of stearyl alcohol was added. The mixture was ultrasonically treated at 550 W for 45 min while stirring to obtain a colloid.

[0079] S211: Fe3O4 nanoparticles were dispersed in ethanol, and ethyl orthosilicate and ammonia were added. The mixture was reacted at 60°C for 6 hours, and then centrifuged, washed, and dried to obtain Fe3O4@SiO2.

[0080] S210: 1 g of Fe3O4@SiO2 was placed in an ethanol solution, 1 g of APTES was added, and the mixture was ultrasonically treated at 300 W for 10 min under magnetic stirring at 500 rpm to obtain a first mixed solution;

[0081] S220: adjusting the pH value of the first mixed solution to 5, stirring under reflux at 80° C. for 4 h, washing the precipitate, and vacuum drying at 60° C. for 12 h to obtain a magnetic carrier;

[0082] S230: dispersing the magnetic carrier in a phosphate buffer solution with a pH of 6, adding a transglycosylase solution with a concentration of 30 mg / mL and an enzyme activity of 250 U / mg while ultrasonicating, stirring magnetically at 60° C. for 1 hour, performing magnetic separation, and then washing and precipitating to obtain an immobilized enzyme catalyst;

[0083] S300: 10 g of colloid was mixed with 1 g of immobilized enzyme catalyst, the pH was adjusted to 6.5, the mixture was stirred at a constant temperature of 60° C. for 5 h, and filtered through a 0.22 μm microporous membrane to obtain a plant-derived surfactant.

[0084] Comparative Example 1

[0085] This comparative example provides a plant-derived surfactant, which is purchased from outside.

[0086] Test data

[0087] The purity, surface tension, yield and HLB value of Examples 1-3 and Comparative Example 1 were tested. The results are shown in Table 1.

[0088] Purity test: HPLC method was used for separation using a C18 column and acetonitrile-water as the mobile phase.

[0089] Surface tension: The surface tension of the aqueous solution containing 0.1% of Examples 1-3 and Comparative Example 1 was measured by platinum plate method, and the measurement was repeated 3 times at a constant temperature of 25°C to obtain the average value;

[0090] Yield: Weigh the mass m0 of the dried product of Examples 1-3, the theoretical yield m1, and the yield is m0 / m1. Taking Example 1 as an example, the theoretical yield value calculation method is as follows:

[0091]

[0092] Product molecular weight = glucose monoglucose unit + fatty alcohol molecular weight - water molecular weight = 162 + 214.36 - 18 = 358.36 g / mol Theoretical output value = min (n glucose , n alcohol )×(molecular weight of product)=0.00617mol×330.33g / mol=2.04g.

[0093] HLB value: Mix the product with a standard emulsifier of known HLB value and determine the HLB by observing the emulsion stability;

[0094] Table 1

[0095] Test items Example 1 Example 2 Example 3 Comparative Example 1 Theoretical yield (g) 2.04 1.67 2.56 / Actual output (g) 1.88 1.47 2.18 / Yield (g) 92 88 85 / purity(%) 98.5 97.2 96.8 82 Surface tension (mN / m) 28.3 29.1 30.5 31.8 HLB value 7.0 6.5 5.8 /

[0096] As can be seen from Table 1, the yields of Examples 1-3 are greater than 85%, indicating that the preparation method of this embodiment has a high conversion efficiency; the purity of Examples 1-3 is much greater than that of Comparative Example 1, proving that the preparation method of this embodiment has strong directionality and high selectivity; the surface tension of Example 1 is the lowest at 28.3 mN / m, indicating that it has the best wettability; the surface tension of Comparative Example 1 is increased due to the large number of impurities; through the design of fatty alcohol chain length, the HLB values ​​of Examples 1-3 are 7.0, 6.5, and 5.8, respectively, covering the needs of oil-in-water to oil-in-water systems. Long-chain stearyl alcohol is suitable for oil-in-water systems, such as skin creams and sunscreens, and short-chain lauryl alcohol is suitable for oil-in-water emulsions, such as shampoos and dishwashing liquids.

[0097] Enzyme activity cycle test: 1mM p-nitrophenol glucoside was used as substrate, and the reaction was carried out at 60℃ for 10 minutes in phosphate buffer with pH 6.5. Then 1M sodium carbonate was added to terminate the reaction. The absorbance of p-nitrophenol was measured at a wavelength of 405nm using a spectrophotometer. By pre-establishing a pNP concentration-absorbance standard curve, such as Figure 1 As shown, the initial activity of the immobilized enzyme per unit mass was calculated; in the cycle test, the catalyst was recovered by magnetic separation after each reaction, washed with phosphate buffer and reused, and the activity retention rate and mass recovery rate after 5 cycles were recorded. The results of Example 1 are shown in Table 2.

[0098] Table 2

[0099] Number of cycles Activity retention rate (%) Mass recovery rate (%) 1 100 100 2 95 98 3 91 96 4 88 94 5 85 92

[0100] As can be seen from Table 2, the activity retention rate of the catalyst in Example 1 after 5 cycles is greater than 85%, and the mass recovery rate is greater than 92%, indicating that it has good operational stability and reusability.

[0101] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0102] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for preparing a plant-derived surfactant, characterized in that: The plant-derived surfactant comprises the following steps: S100: Under an inert atmosphere, microcrystalline cellulose is dispersed in a solvent, and a fatty alcohol is added, and the mixture is stirred while being ultrasonically treated to obtain a colloid; S200: mixing the magnetic carrier with the transglycosylase solution to perform an adsorption reaction to obtain an immobilized enzyme catalyst; S300: mixing the colloid and the immobilized enzyme catalyst, adjusting the pH to 5-7, and sequentially performing constant temperature stirring treatment and filtering treatment to obtain the plant-derived surfactant.

2. The preparation method according to claim 1, characterized in that In step S100, The inert atmosphere includes at least one of nitrogen and argon; and / or The fatty alcohol has a carbon chain length of C 12 -C 18 Medium and long chain fatty alcohols; and / or The solvent comprises glycerol; and / or The mass ratio of the microcrystalline cellulose: the solvent: the fatty alcohol is 1: (4-6): (1-3); and / or The power of the ultrasonic treatment is 500-600W, and the time is 30-60min.

3. The preparation method according to claim 1, characterized in that In step S100, the fatty alcohol includes at least one of lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol.

4. The preparation method according to claim 1, characterized in that Step S200 specifically includes: S210: placing the magnetic nanoparticles in an ethanol solution, adding 3-aminopropyltriethoxysilane, and ultrasonically treating the solution under magnetic stirring to obtain a first mixed solution; S220: adjusting the pH value of the first mixed solution to a range of 4-6, heating to 70-90° C., refluxing with stirring for 3-5 hours, washing and precipitating, and vacuum drying to obtain the magnetic carrier; S230: dispersing the magnetic carrier in phosphate buffer, adding transglycosylase solution while ultrasonically treating the magnetic carrier, and sequentially performing magnetic stirring treatment, magnetic separation treatment, washing and precipitation treatment to obtain the immobilized enzyme catalyst.

5. The preparation method according to claim 4, characterized in that In step S210, the magnetic nanoparticles include Fe3O4@SiO2 or Fe3O4; and / or In step S210, the ultrasonic treatment time is 5-15 minutes and the power is 200-400W; and / or In step S210, the mass ratio of the magnetic nanoparticles to the 3-aminopropyltriethoxysilane is 1:(0.5-1.2); and / or In step S210, the rotation speed of the magnetic stirring is 400-600 rpm; and / or In step S220, the vacuum drying temperature is 50-70°C and the time is 10-14 hours; and / or In step S230, the stirring treatment temperature is 50-70°C and the time is 0.5-2h; and / or In step S230, the pH value of the phosphate buffer is 5-7; and / or In step S230, the concentration of the transglycosylase solution is 10-50 mg / mL.

6. The preparation method according to claim 1, characterized in that In step S300, The mass ratio of the colloid to the immobilized enzyme catalyst is (5-10):1; and / or The constant temperature stirring treatment is performed at a temperature of 55-68° C. for 4-6 hours; and / or The filtration treatment adopts 0.20-0.25 μm microporous membrane filtration.

7. The preparation method according to claim 1, characterized in that Before step S100, the following steps are also included: S000, subjecting the microcrystalline cellulose to an acid hydrolysis pretreatment to control the degree of polymerization of the microcrystalline cellulose to 50-100.

8. The preparation method according to claim 7, characterized in that The acid hydrolysis conditions include: using 0.5-1 mol / L sulfuric acid and treating at a temperature of 60-80° C. for 1-2 hours.

9. The preparation method according to claim 1, characterized in that The plant-derived surfactant is cellulose alkyl glycoside, which has the following molecular structure formula: (C6H 10 O5) n -OR; Among them, R is the length of C 12 -C 18 A straight chain or branched alkyl group, n is a degree of polymerization between 10-30.

10. A plant-derived surfactant, characterized in that: The plant-derived surfactant is prepared by the preparation method according to any one of claims 1 to 9.

Images