Method for extracting beta-arbutin from beta-arbutin fermentation liquor

Abstract

The invention relates to the technical field of beta-arbutin extraction, and discloses a method for extracting beta-arbutin from beta-arbutin fermentation liquor. The method comprises the steps of separating and removing mycoprotein, passing through an ultrafiltration membrane, passing through a nanofiltration membrane, passing through a reverse osmosis membrane, decolorizing, concentrating and crystallizing. The method can effectively improve the impurity removal efficiency of the fermentation liquor, shorten the process time, improve the product content and the product yield, reduce the energy consumption, reduce the cost, and reduce the discharge and treatment difficulty of wastewater. In addition, membrane concentration process conditions are mild, the product decomposition rate is low, and the extraction income is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of beta-arbutin extraction, and in particular to a method for extracting beta-arbutin from beta-arbutin fermentation broth. Background Art

[0002] Arbutin, also known as arbutin or hydroquinone glucoside (C 12 H 16 Arbutin is a kind of emerging natural whitening active substance with no stimulation, no allergy and strong compatibility, which has a significant skin whitening effect. It was first introduced as a cosmetic whitening agent by Shiseido Cosmetics Co., Ltd. of Japan in the 1990s. At present, arbutin has monopolized the whitening and skin care market in developed countries. Arbutin not only has a fading effect on freckles, age spots and chloasma of the skin, but also has a good effect on the moisturizing of the skin, the healing of skin burns and acne. Currently known arbutin includes α-arbutin, β-arbutin and deoxyarbutin (D-Arbutin). Among them, the price of β-arbutin is lower than that of α-arbutin, and the preparation process is also simpler, so β-arbutin is still the most produced by various companies.

[0003] At present, β-arbutin can be obtained through a variety of methods such as plant extraction, plant cell culture, enzyme conversion, chemical synthesis, and microbial fermentation. Due to the constraints of low yield and high cost, the first three methods are rarely used in the industrial production of β-arbutin. The industrial production of β-arbutin mostly adopts chemical synthesis, which is to acetylate hydroquinone to obtain β-pentaacetyl arbutin, and then deprotect to obtain β-arbutin. This method is carried out under normal pressure, with high yield, easy to obtain raw materials, simple operation, and suitable for large-scale industrial production, but it has great environmental pollution, complex production, and production is subject to the price of raw materials.

[0004] The microbial fermentation method has the characteristics of mild reaction conditions. CN201910968220.6 discloses an engineered bacterium for producing β-arbutin, which produces β-arbutin with carbon sources such as glucose and glycerol, and realizes the de novo synthesis of β-arbutin. However, the β-arbutin fermentation broth obtained by the fermentation method contains a large amount of impurities such as organic pigments and bacterial proteins. At present, the extraction process of β-arbutin is to separate the bacterial cells and macromolecular proteins in the fermentation broth from the β-arbutin fermentation broth through a ceramic membrane, and then use a macroporous adsorption resin to adsorb β-arbutin and then wash and remove impurities, and finally decolorize, concentrate, cool and crystallize to obtain β-arbutin. The use of macroporous adsorption resin in the extraction process will produce a large amount of acid washing and alkali washing wastewater, and the whole process time will be longer. In addition, since β-arbutin is unstable and easy to decompose at high temperature, the product will have different degrees of product decomposition during the extraction process, and the glucose produced by the decomposition seriously affects the crystallization and color of the product. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems that a large amount of acid washing and alkali washing wastewater is generated by using macroporous adsorption resin adsorption in the existing β-arbutin extraction process, and the process time is long, and to provide a method for extracting β-arbutin from β-arbutin fermentation broth, thereby shortening the process time and reducing the cost.

[0006] In order to achieve the above object, the present invention provides a method for extracting β-arbutin from β-arbutin fermentation broth, the method comprising the following steps:

[0007] (1) separating and removing bacterial protein from the β-arbutin fermentation broth, and then filtering through an ultrafiltration membrane to obtain a clear liquid;

[0008] (2) performing primary concentration on the clear liquid after the membrane filtration through a nanofiltration membrane to obtain a primary concentrated liquid containing β-arbutin;

[0009] (3) performing secondary concentration on the obtained primary concentrated solution through a reverse osmosis membrane to obtain a secondary concentrated solution;

[0010] (4) decolorizing the secondary concentrated solution obtained in step (3) to obtain a decolorized clear solution;

[0011] (5) Concentrating the decolorized clear liquid and crystallizing it to obtain β-arbutin crystals.

[0012] Preferably, in step (1), before separating and removing bacterial protein, the method further comprises adjusting the pH value of the β-arbutin fermentation broth to acidic; preferably, the acidic pH value ranges from 4 to 6.

[0013] Preferably, in step (1), the bacterial protein is separated and removed from the fermentation broth by filtering the fermentation broth through a ceramic membrane, flocculating with acid or adding a flocculant; preferably, the bacterial protein is removed by filtering the fermentation broth through a ceramic membrane.

[0014] Preferably, in step (1), the operating temperature of the ceramic membrane is 30-60°C.

[0015] Preferably, in step (1), the operating temperature of the ultrafiltration membrane is 40-60°C, and the molecular weight cut-off is 1000-2000D.

[0016] Preferably, in step (1), the content of β-arbutin in the membrane clear solution is 35-45 g / L

[0017] Preferably, in step (2), the operating temperature of the nanofiltration membrane is 40-60°C, and the molecular weight cut-off is 150-250D.

[0018] Preferably, the content of β-arbutin in the primary concentrated solution containing β-arbutin is 140-160 g / L.

[0019] Preferably, in step (3), the operating temperature of the reverse osmosis membrane is 45-60°C.

[0020] Preferably, in step (3), the content of β-arbutin in the secondary concentrated solution is 240-260 g / L.

[0021] Preferably, in step (4), activated carbon is used for decolorization.

[0022] Preferably, in step (4), based on 100 mL of the secondary concentrated liquid, the amount of activated carbon used is 0.5-1 g.

[0023] Preferably, the decolorization treatment conditions include: temperature of 40-60°C and time of 30-60 min.

[0024] Preferably, in step (5), the decolorized clear solution is concentrated to a β-arbutin content of 450-500 g / L.

[0025] Preferably, the concentration conditions include: pressure of -0.085 to -0.095 MPa and temperature of 50-65°C.

[0026] Preferably, in step (5), the crystallization is carried out by cooling crystallization.

[0027] Preferably, in step (5), the process further comprises subjecting the crude β-arbutin crystals obtained by crystallization to recrystallization.

[0028] Preferably, the crystallization and recrystallization conditions include: temperature of 0-25°C and time of 2-5h.

[0029] Beneficial effects: The technical solution of the present invention uses ceramic membrane and ultrafiltration membrane to treat β-arbutin fermentation broth, and then the obtained clear liquid is concentrated through nanofiltration membrane and reverse osmosis membrane, which can effectively improve the impurity removal efficiency of the fermentation broth, shorten the process time, improve product purity (content ≥ 99 mass%) and product yield, reduce energy consumption, and reduce costs. In addition, the membrane concentration process conditions are mild, the product decomposition rate is low, and the extraction yield is greatly improved. The entire process avoids the use of macroporous adsorption resins, reduces the discharge and treatment difficulty of wastewater. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] The present invention provides a method for extracting β-arbutin from β-arbutin fermentation broth, the method comprising the following steps:

[0033] (1) separating and removing bacterial protein from the β-arbutin fermentation broth, and then filtering through an ultrafiltration membrane to obtain a clear liquid;

[0034] (2) performing primary concentration on the clear liquid after the membrane filtration through a nanofiltration membrane to obtain a primary concentrated liquid containing β-arbutin;

[0035] (3) performing secondary concentration on the obtained primary concentrated solution through a reverse osmosis membrane to obtain a secondary concentrated solution;

[0036] (4) decolorizing the secondary concentrated solution obtained in step (3) to obtain a decolorized clear solution;

[0037] (5) Concentrating the decolorized clear liquid and crystallizing it to obtain β-arbutin crystals.

[0038] The β-arbutin fermentation broth of the present invention is obtained by a glucose fermentation process. Specifically, the β-arbutin fermentation broth can be obtained by fermenting the recombinant Escherichia coli BW6 disclosed in CN112646761A. In addition to β-arbutin, the β-arbutin fermentation broth also contains bacterial proteins, macromolecular proteins, small molecular impurities, organic pigments, glucose and other impurities.

[0039] According to the method of the present invention, in step (1), the bacterial protein in the fermentation broth is first separated and removed, and then the obtained clear liquid is filtered through an ultrafiltration membrane to remove part of small molecular impurities and organic pigments to obtain a clear liquid after the membrane is passed; in step (2), the clear liquid after the membrane is passed through a nanofiltration membrane for primary concentration, and the nanofiltration membrane can remove most of the small molecular pigments, glucose and other impurities; in step (3), the clear liquid after the membrane is passed through a reverse osmosis membrane for secondary concentration, and the secondary membrane concentration process can effectively improve the impurity removal efficiency of the fermentation broth, shorten the process time, increase the product yield, reduce energy consumption, and reduce costs; in step (4), the light transmittance of the concentrated liquid after decolorization is significantly improved; in step (5), after concentration and crystallization, bright-colored and high-purity β-arbutin crystals can be obtained.

[0040] In step (1), before separating and removing bacterial protein from the β-arbutin fermentation broth, the method further includes adjusting the pH value of the β-arbutin fermentation broth to acidic to improve the stability of the β-arbutin in the fermentation broth.

[0041] In the method of the present invention, a conventional acidic solution can be used to adjust the pH value of the fermentation broth. Specifically, the acidic solution can be a sulfuric acid solution. Preferably, in order to further improve the stability of β-arbutin in the fermentation broth and facilitate subsequent operations, the acidic pH value range can be 4-6.

[0042] Furthermore, in step (1), before adjusting the pH value of the fermentation liquid, the β-arbutin fermentation liquid is subjected to high temperature sterilization. The conditions for the high temperature sterilization can be conventionally selected in the art; preferably, the temperature of the high temperature sterilization can be 80-90° C., and the time of the high temperature sterilization can be 10-20 minutes.

[0043] According to the present invention, in step (1), bacterial protein can be separated and removed from the fermentation broth in a manner well known in the art. Specifically, the method used to separate and remove bacterial protein from the fermentation broth is: filtering the fermentation broth through a ceramic membrane, adding acid flocculation or adding a flocculant, preferably filtering the fermentation broth through a ceramic membrane to remove bacterial protein.

[0044] In a specific embodiment, in step (1), the operating temperature of the ceramic membrane may be 30-60° C. Further, the specification of the ceramic membrane is 50-200 nm.

[0045] In the present invention, in order to remove some small molecular impurities and organic pigments and prevent the loss of β-arbutin, preferably, in step (1), the operating temperature of the ultrafiltration membrane can be 40-60° C. and the molecular weight cutoff can be 1000-2000D.

[0046] In a specific embodiment, the content of β-arbutin in the membrane clear liquid obtained after the treatment in step (1) can be 35-45 g / L.

[0047] In order to remove some small molecular impurities and organic pigments in the clear liquid passing through the membrane to obtain a primary concentrated liquid containing β-arbutin, preferably, the molecular weight cutoff of the nanofiltration membrane is 150-250D. The retention rate of the nanofiltration membrane for β-arbutin is 80-90%.

[0048] In the present invention, the nanofiltration membrane can be operated at a relatively low temperature. Preferably, in step (2), the operating temperature of the nanofiltration membrane is 40-60° C. The operation of the nanofiltration membrane at this temperature can effectively prevent the decomposition of β-arbutin and improve the extraction yield of β-arbutin.

[0049] In a specific embodiment, the content of β-arbutin in the primary concentrated solution obtained after the supernatant passes through the nanofiltration membrane can be 140-160 g / L.

[0050] In the method of the present invention, the nanofiltration membrane and the reverse osmosis membrane are used in combination to further improve the extraction yield of β-arbutin and the purity of β-arbutin.

[0051] The reverse osmosis membrane can be operated at a relatively low temperature. Specifically, in step (3), the operating temperature of the reverse osmosis membrane (RO membrane) can be 45-60° C. When the reverse osmosis membrane is operated at this temperature, it can not only further effectively prevent the decomposition of β-arbutin and improve the extraction yield of β-arbutin, but also further save costs.

[0052] Specifically, in step (3), the content of β-arbutin in the secondary concentrated liquid obtained after treatment with the reverse osmosis membrane can be 240-260 g / L.

[0053] In the present invention, when the reverse osmosis membrane concentrates to a content of β-arbutin in the secondary concentrated liquid of 240-260 g / L, the concentration efficiency begins to deteriorate, and the color of the membrane concentrated liquid obtained at this time is still very dark. Through detection, the transmittance is only 20-30%, and decolorization treatment is required. After decolorization treatment, the transmittance is significantly improved from 20-30% to 80-90%.

[0054] In the method of the present invention, the decolorization treatment can be carried out in a manner well known in the art. Preferably, in step (4), the decolorization treatment is carried out using activated carbon; more preferably, the activated carbon can be wood activated carbon.

[0055] In order to improve the decolorization effect, preferably, in step (3), the decolorization conditions include: the temperature can be 40-60°C, and the time can be 30-60 minutes.

[0056] In order to further improve the decolorization effect, the amount of activated carbon should be appropriate. Preferably, in step (3), based on 100 mL of the secondary concentrated solution, the amount of activated carbon used is 0.5-1 g, that is, the ratio of the activated carbon to the secondary concentrated solution is 0.5-1 g: 100 mL.

[0057] In a more specific embodiment, in step (3), the decolorization treatment is followed by filtration. Specifically, the filtration can be performed using various devices well known to those skilled in the art, preferably, a plate and frame filter press is used for filtration.

[0058] In one embodiment, step (5) specifically comprises: concentrating the decolorized clear solution, crystallizing it, and centrifuging and drying it to obtain β-arbutin crystals.

[0059] In the present invention, the concentration and crystallization process are determined according to actual needs.

[0060] In order to improve the concentration effect, in step (4), the concentration is vacuum concentration; preferably, the concentration conditions include: pressure of -0.085 to -0.095 MPa and temperature of 50-65°C.

[0061] In step (5), the crystallization method is preferably cooling crystallization.

[0062] In a preferred embodiment, in step (5), the decolorized supernatant can be concentrated to a β-arbutin content of 450-500 g / L by concentration.

[0063] Furthermore, in step (5), the crude β-arbutin crystals obtained by crystallization are further subjected to recrystallization.

[0064] In another embodiment, step (5) specifically comprises: concentrating the decolorized clear liquid, crystallizing, and centrifuging to obtain a primary crystal crude product, and then recrystallizing the primary crystal crude product, centrifuging and drying to obtain β-arbutin crystals.

[0065] In the present invention, in order to improve the crystallization effect and thus improve the extraction yield of β-arbutin, preferably, in step (5), the conditions for crystallization and recrystallization include: temperature of 0-25° C. and time of 2-5 h.

[0066] The method of the present invention can not only avoid the generation of a large amount of acid washing and alkali washing wastewater, but also shorten the process time, save costs, reduce energy consumption and improve product content.

[0067] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0068] In the present invention, the extraction yield of β-arbutin = the mass of β-arbutin in the refined β-arbutin finally extracted in step (4) / the mass of β-arbutin in the β-arbutin fermentation broth in step (1)).

[0069] Example 1

[0070] (1) sterilizing the β-arbutin fermentation broth at 85° C. for 15 min, adjusting the pH value of the sterilized fermentation broth to 5 with a 50% by mass sulfuric acid solution, separating bacterial protein from the fermentation broth through a ceramic membrane, and then removing small molecular weight proteins and most organic pigments through an ultrafiltration membrane; wherein the operating temperature of the ceramic membrane is 50° C.; the operating temperature of the ultrafiltration membrane is 60° C., and the molecular weight cutoff is 1000D, and obtaining a membrane clear liquid with a β-arbutin content of 40 g / L;

[0071] (2) The supernatant liquid is concentrated through a 250D nanofiltration membrane to obtain a first-level concentrated liquid with a β-arbutin content of 150 g / L, wherein the 250D nanofiltration membrane concentration process can remove most small molecular pigments, glucose and other impurities, and the operating temperature of the 250D nanofiltration membrane is 45° C.; then the first-level concentrated liquid is concentrated through an RO membrane to obtain a second-level concentrated liquid with a β-arbutin content of 250 g / L and a light transmittance of 31%, wherein the operating temperature of the RO membrane is 50° C.;

[0072] (3) After the secondary concentration is completed, the secondary concentrate is transferred to a decolorization tank, and wood activated carbon is added (the ratio of wood activated carbon to secondary concentrate is 0.8 g: 100 mL), and the mixture is stirred and decolorized at a constant temperature of 50° C. for 40 min. The transmittance of the secondary concentrate is increased to 90%, and then filtered using a plate and frame filter press to obtain a decolorized clear liquid;

[0073] (4) The decolorized clear liquid is vacuum concentrated at a pressure of -0.09 MPa and a temperature of 60°C. The concentration at the end point of concentration is controlled at 470 g / L of β-arbutin. After the concentration is completed, the temperature is lowered to 10°C for crystallization and the crystals are cultured for 3 hours. After the crystal culture is completed, centrifugal separation is started to obtain a crude primary crystal product, and the crude primary product is redissolved and recrystallized, and centrifuged and dried to obtain fine β-arbutin crystals.

[0074] After testing and calculation, the purity of the β-arbutin product obtained in this embodiment is 99.9% by mass, the extraction yield is 65.1%, and the production cost per ton is 170,000 yuan.

[0075] Example 2

[0076] (1) sterilizing the β-arbutin fermentation broth at 90° C. for 12 min, adjusting the pH value of the sterilized fermentation broth to 4 with a 50% by mass sulfuric acid solution, separating bacterial protein from the fermentation broth through a ceramic membrane, and then removing small molecular weight proteins and most organic pigments through an ultrafiltration membrane, wherein the operating temperature of the ceramic membrane is 30° C.; the operating temperature of the ultrafiltration membrane is 40° C., and the molecular weight cutoff is 1500D, to obtain a clear solution having a β-arbutin content of 45 g / L;

[0077] (2) The supernatant liquid is concentrated through a 150D nanofiltration membrane to obtain a first-level concentrated liquid with a β-arbutin content of 158 g / L, wherein the 150D nanofiltration membrane concentration process can remove most small molecular pigments, glucose and other impurities, and the operating temperature of the 150D nanofiltration membrane is 45° C., and then the first-level concentrated liquid is concentrated through an RO membrane to obtain a second-level concentrated liquid with a β-arbutin content of 260 g / L and a light transmittance of 18%, wherein the operating temperature of the RO membrane is 50° C.;

[0078] (3) After the secondary concentration is completed, the secondary concentrate is transferred to a decolorization tank, and wood activated carbon is added (the ratio of wood activated carbon to secondary concentrate is 0.6 g: 100 mL), and the mixture is stirred and decolorized at a constant temperature of 40°C for 50 minutes. The transmittance of the secondary concentrate is increased to 84%, and then filtered using a plate and frame filter press to obtain a decolorized clear liquid;

[0079] (4) The decolorized clear liquid is vacuum concentrated at a pressure of -0.09 MPa and a temperature of 55°C. The concentration at the end point of concentration is controlled at a β-arbutin content of 450 g / L. After the concentration is completed, the temperature is lowered to 10°C for crystallization and the crystals are grown for 4 hours. After the crystal growth is completed, centrifugal separation is started to obtain a crude primary crystal product, and the crude primary product is redissolved and recrystallized, and centrifuged and dried to obtain fine β-arbutin crystals.

[0080] After testing and calculation, the purity of the β-arbutin product obtained in this embodiment is 99.9% by mass, the extraction yield is 61.9%, and the production cost per ton is 180,000 yuan.

[0081] Example 3

[0082] (1) sterilizing the β-arbutin fermentation broth at 85° C. for 15 min, adjusting the pH value of the sterilized fermentation broth to 6 with a 50% by mass sulfuric acid solution, separating bacterial protein from the fermentation broth through a ceramic membrane, and then removing small molecular weight proteins and most organic pigments through an ultrafiltration membrane, wherein the operating temperature of the ceramic membrane is 60° C.; the operating temperature of the ultrafiltration membrane is 50° C., and the molecular weight cutoff is 2000D, to obtain a membrane clear liquid with a β-arbutin content of 35 g / L;

[0083] (2) The supernatant liquid is concentrated through a 200D nanofiltration membrane to obtain a first-level concentrated liquid with a β-arbutin content of 142 g / L, wherein the 200D nanofiltration membrane concentration process can remove most small molecular pigments, glucose and other impurities, and the operating temperature of the 200D nanofiltration membrane is 45° C., and then the first-level concentrated liquid is concentrated through an RO membrane to obtain a second-level concentrated liquid with a β-arbutin content of 240 g / L and a light transmittance of 23%, wherein the operating temperature of the RO membrane is 50° C.;

[0084] (3) After the secondary concentration is completed, the secondary concentrate is put into a decolorization tank, and wood activated carbon is added (the ratio of wood activated carbon to secondary concentrate is 0.5 g: 100 mL), and the decolorization is carried out at a constant temperature of 60°C for 60 minutes. The transmittance of the secondary concentrate is increased to 85%, and then filtered using a plate and frame filter press to obtain a decolorized clear liquid;

[0085] (4) The decolorized clear liquid is vacuum concentrated at a pressure of -0.09 MPa and a temperature of 65°C. The concentration at the end point of concentration is controlled at a β-arbutin content of 500 g / L. After the concentration is completed, the temperature is lowered to 10°C for crystallization and the crystals are cultured for 3 hours. After the crystal culture is completed, centrifugal separation is started to obtain a crude primary crystal product, and the crude primary product is redissolved and recrystallized, and centrifuged and dried to obtain fine β-arbutin crystals.

[0086] After testing and calculation, the purity of the β-arbutin product obtained in this embodiment is 99.9% by mass, the extraction yield is 60.6%, and the production cost per ton is 170,000.

[0087] Comparative Example 1

[0088] The method of Example 1 is followed, except that in step (2), the treatment is not performed through an RO membrane.

[0089] Specific operations include:

[0090] (1) sterilizing the β-arbutin fermentation broth at 85° C. for 15 min, adjusting the pH value of the sterilized fermentation broth to 5 with a 50% by mass sulfuric acid solution, separating bacterial protein from the fermentation broth through a ceramic membrane, and then removing small molecular weight proteins and most organic pigments through an ultrafiltration membrane; wherein the operating temperature of the ceramic membrane is 50° C.; the operating temperature of the ultrafiltration membrane is 60° C., and the molecular weight cutoff is 1000D, and obtaining a membrane clear liquid with a β-arbutin content of 40 g / L;

[0091] (2) The clear liquid is passed through a 250D nanofiltration membrane for primary concentration, wherein the operating temperature of the 250D nanofiltration membrane is 45° C. The 250D nanofiltration membrane concentration process can remove most of the small molecular pigments, glucose and other impurities to obtain a primary concentrated liquid with a β-arbutin content of 150 g / L. At this time, the concentration efficiency begins to deteriorate, and the transmittance of the primary concentrated liquid is 40%;

[0092] (3) After the first-stage concentration is completed, the first-stage concentrated liquid is transferred to a decolorization tank, and wood activated carbon is added (the ratio of wood activated carbon to the first-stage concentrated liquid is 0.8 g: 100 mL), and the decolorization is carried out by stirring at a constant temperature of 50° C. for 40 minutes. The transmittance of the first-stage concentrated liquid is increased to 89%, and then filtered using a plate and frame filter press to obtain a decolorized clear liquid;

[0093] (4) The decolorized clear liquid is vacuum concentrated at a pressure of -0.09 MPa and a temperature of 60°C. The concentration at the end point of concentration is controlled at 470 g / L of β-arbutin. After the concentration is completed, the temperature is lowered to 10°C for crystallization and the crystals are cultured for 3 hours. After the crystal culture is completed, centrifugal separation is started to obtain a crude primary crystal product, and the crude primary product is redissolved and recrystallized, and centrifuged and dried to obtain fine β-arbutin crystals.

[0094] After testing and calculation, the purity of the β-arbutin product obtained in this embodiment is 99.8% by mass, the extraction yield is 62.1%, and the production cost per ton is 190,000 yuan.

[0095] The content of the β-arbutin product obtained by the method described in this comparative example is less than 99.9%, and is not suitable for use in the fields of medicine and cosmetic additives.

[0096] Comparative Example 2

[0097] The method of Example 1 was followed, except that no 250D nanofiltration membrane and RO membrane were used for treatment.

[0098] The specific process includes:

[0099] (1) sterilizing the β-arbutin fermentation broth at 85° C. for 15 min, adjusting the pH value of the sterilized fermentation broth to 5 with a 50% by mass sulfuric acid solution, separating bacterial protein from the fermentation broth through a ceramic membrane, and then removing small molecular weight proteins and most organic pigments through an ultrafiltration membrane; wherein the operating temperature of the ceramic membrane is 50° C.; the operating temperature of the ultrafiltration membrane is 60° C., and the molecular weight cutoff is 1000D, and obtaining a clear solution having a β-arbutin content of 40 g / L and a light transmittance of 50%;

[0100] (2) The clear liquid is poured into a decolorization tank, and wood activated carbon is added (the ratio of wood activated carbon to clear liquid is 0.8 g: 100 mL), and the mixture is stirred and decolorized at a constant temperature of 50° C. for 40 min. The transmittance of the clear liquid is increased to 90%, and then filtered using a plate and frame filter press to obtain a decolorized clear liquid;

[0101] (4) The decolorized clear liquid is vacuum concentrated at a pressure of -0.09 MPa and a temperature of 60°C. The concentration at the end point of concentration is controlled at 470 g / L of β-arbutin. After the concentration is completed, the temperature is lowered to 10°C for crystallization and the crystals are cultured for 3 hours. After the crystal culture is completed, centrifugal separation is started to obtain a crude primary crystal product, and the crude primary product is redissolved and recrystallized, and centrifuged and dried to obtain fine β-arbutin crystals.

[0102] After testing and calculation, the purity of the β-arbutin product obtained in this comparative example is 99.5% by mass, the extraction yield is 43.9%, and the production cost per ton is 260,000 yuan.

[0103] Comparative Example 3

[0104] The method of Example 1 was followed, except that no 250D nanofiltration membrane was used for treatment.

[0105] (1) sterilizing the β-arbutin fermentation broth at 85° C. for 15 min, adjusting the pH value of the sterilized fermentation broth to 5 with a 50% by mass sulfuric acid solution, separating bacterial protein from the fermentation broth through a ceramic membrane, and then removing small molecular weight proteins and most organic pigments through an ultrafiltration membrane; wherein the operating temperature of the ceramic membrane is 50° C.; the operating temperature of the ultrafiltration membrane is 60° C., and the molecular weight cutoff is 1000D, and obtaining a membrane clear liquid with a β-arbutin content of 40 g / L;

[0106] (2) Concentrating the clear liquid through an RO membrane, wherein the operating temperature of the RO membrane is 50° C., to obtain a concentrated liquid having a β-arbutin content of 250 g / L and a light transmittance of 18%;

[0107] (3) After the concentration is completed, the concentrate is transferred to a decolorization tank, and wood activated carbon is added (the ratio of wood activated carbon to secondary concentrate is 0.8 g: 100 mL), and the concentrate is stirred and decolorized at a constant temperature of 50° C. for 40 minutes. The transmittance of the concentrate is increased to 75-87%, and then filtered using a plate and frame filter press to obtain a decolorized clear liquid;

[0108] (4) The decolorized clear liquid is vacuum concentrated at a pressure of -0.09 MPa and a temperature of 60°C. The concentration at the end point of concentration is controlled at 470 g / L of β-arbutin. After the concentration is completed, the temperature is lowered to 10°C for crystallization and the crystals are cultured for 3 hours. After the crystal culture is completed, centrifugal separation is started to obtain a crude primary crystal product, and the crude primary product is redissolved and recrystallized, and centrifuged and dried to obtain fine β-arbutin crystals.

[0109] After testing and calculation, the purity of the β-arbutin product obtained in this comparative example is 99.6% by mass, the extraction yield is 51.5%, and the production cost per ton is 230,000 yuan.

[0110] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for extracting β-arbutin from β-arbutin fermentation broth, characterized in that: The method comprises the following steps: (1) separating and removing bacterial protein from the β-arbutin fermentation broth, and then filtering through an ultrafiltration membrane to obtain a clear liquid; (2) performing primary concentration on the clear liquid after the membrane filtration through a nanofiltration membrane to obtain a primary concentrated liquid containing β-arbutin; (3) performing secondary concentration on the obtained primary concentrated solution through a reverse osmosis membrane to obtain a secondary concentrated solution; (4) decolorizing the secondary concentrated solution obtained in step (3) to obtain a decolorized clear solution; (5) Concentrating the decolorized clear liquid and crystallizing it to obtain β-arbutin crystals.

2. The method according to claim 1, characterized in that In step (1), before separating and removing bacterial protein, the pH value of the β-arbutin fermentation broth is adjusted to acidic; preferably, the acidic pH value range is 4-6.

3. The method according to claim 1 or 2, characterized in that: In step (1), the bacterial protein is separated and removed from the fermentation broth by filtering the fermentation broth through a ceramic membrane, adding acid for flocculation, or adding a flocculant; preferably, the bacterial protein is removed by filtering the fermentation broth through a ceramic membrane; Preferably, in step (1), the operating temperature of the ceramic membrane is 30-60°C.

4. The method according to any one of claims 1 to 3, characterized in that: In step (1), the operating temperature of the ultrafiltration membrane is 40-60°C, and the molecular weight cut-off is 1000-2000D.

5. The method according to any one of claims 1 to 4, characterized in that: In step (2), the operating temperature of the nanofiltration membrane is 40-60°C and the molecular weight cut-off is 150-250D; Preferably, the content of β-arbutin in the primary concentrated solution containing β-arbutin is 140-160 g / L.

6. The method according to any one of claims 1 to 5, characterized in that: In step (3), the operating temperature of the reverse osmosis membrane is 45-60°C; Preferably, in step (3), the content of β-arbutin in the secondary concentrated solution is 240-260 g / L.

7. The method according to any one of claims 1 to 6, characterized in that: In step (4), activated carbon is used for decolorization; Preferably, in step (4), the amount of activated carbon used is 0.5-1 g based on 100 mL of the secondary concentrated solution; Preferably, the decolorization treatment conditions include: temperature of 40-60°C and time of 30-60 min.

8. The method according to any one of claims 1 to 7, characterized in that: In step (5), the decolorized supernatant is concentrated to a β-arbutin content of 450-500 g / L; Preferably, the concentration conditions include: pressure of -0.085 to -0.095 MPa and temperature of 50-65°C.

9. The method according to any one of claims 1 to 8, characterized in that: In step (5), the crystallization method is cooling crystallization.

10. The method according to any one of claims 1 to 9, characterized in that: In step (5), the step further includes subjecting the crude β-arbutin crystals obtained by crystallization to recrystallization; Preferably, the crystallization and recrystallization conditions include: temperature of 0-25°C and time of 2-5h.