An industrial purification method of rhamnolipid

Abstract

The present invention belongs to the technical field of rhamnolipid separation and purification, and particularly relates to an industrial purification method for rhamnolipid, which comprises the following steps: 1) Drying: Drying refers to the process of converting the raw material into a powdery solid, i.e., dry powder, and the raw material is rhamnolipid fermentation broth or concentrated slurry of bacterial residue; 2) Extraction; 3) Ceramic membrane filtration: Filtering the extract with a 100-200 nm ceramic membrane to filter out the impurities floating on the upper layer and suspended in the middle; 4) Alkali precipitation; 5) Nanofiltration membrane filtration; 6) Vacuum concentration: Concentrating the nanofiltration concentrate with a vacuum concentrator, controlling the vacuum degree at -0.06 to -0.08 MPa and the temperature at 60 to 80 °C; Sampling during the concentration process and detecting the solid content by the drying method. When the solid content reaches 45-55%, stop the concentration and discharge the material. From the perspective of industrialization, the present invention takes into account cost, efficiency and separation effect, and has the characteristics of being easy to implement, easy to operate and having low emissions.

Description

Technical Field

[0001] The present invention belongs to the technical field of rhamnolipid separation and purification, and particularly relates to an industrial purification method of rhamnolipid. Background Art

[0002] Rhamnolipid is a surfactant produced by biological fermentation method and is also the first variety of biosurfactant to achieve industrialized batch fermentation. Rhamnolipid has excellent surface properties and is widely used in various fields. Due to its safe, non-toxic, environmentally friendly and easily degradable characteristics, it has gradually replaced some traditional chemical surfactants. For example, it is used in oil exploitation, agricultural fertilizer efficiency enhancement, industrial and civil cleaning, cosmetics, and even food and medicine fields. With its wider and higher-end applications, the quality requirements for rhamnolipid itself are getting higher and higher. There have been people researching the technology of purifying rhamnolipid from fermentation broth, and different purification schemes have emerged, but there is still no suitable and truly industrializable scheme.

[0003] The strains for producing rhamnolipid are mainly Pseudomonas aeruginosa. Due to the characteristics of such strains, they are more likely to use hydrophobic carbon sources for fermentation. Therefore, at present, natural vegetable oils are generally used as the carbon source for rhamnolipid fermentation in industrial fermentation, which has high lipid production, short fermentation time and easy process control. When the fermentation reaches the end point, the yield of rhamnolipid generally reaches 50 - 60 g / L, and there will still be about 0.5 - 1% of the main carbon source remaining in the fermentation broth, which exists in the form of vegetable oil or its decomposition products fatty acids and hydroxy fatty acids. At this time, oil or fatty acids, water, surfactants, biosynthetic intermediates, remaining organic or inorganic nutrient components, etc. coexist in the fermentation broth system. Under the action of surfactants, oil or fatty acids form a stable emulsified and solubilized state with water. At the present stage, from a technical perspective, there are completely methods for high-quality purification and separation, but there are very few industrializable practical application schemes. From an industrial perspective, the two feasible technical schemes and their advantages and disadvantages are as follows:

[0004] (1) Extraction method

[0005] The separation effect is achieved by taking advantage of the different solubilities of rhamnolipids in the organic phase and the aqueous phase under different pH conditions. The advantages of this method are that the process is simple and easy to implement, and the investment in industrial equipment is relatively small. With good control, a yield of 60% can be achieved. The disadvantages are also obvious. First, the amount of liquid to be treated is extremely large. The extraction method generally starts from the fermentation broth or its concentrated solution, and the single use of the organic solvent is at least twice the amount of the liquid. At the same time, the organic solvent will also have a solubility of 5-10% in the water of the fermentation broth. It is not worthwhile to evaporate and recover these dissolved solvents, and emissions are not allowed. Second, although the process is simple, in order to remove different impurities in the organic phase and the aqueous phase as cleanly as possible, repeated phase conversion operations are required, generally 5-8 times. In each process, in order to reduce losses and increase the yield, a reverse solvent needs to be used for extraction 3-5 more times. The recovery cost of the solvent, the loss rate, and the amount of sewage will all increase. In addition, occupational health, production safety, environmental protection treatment, and emissions are also major problems that are difficult to avoid. Third, it is difficult to achieve a high purity. Some by-products will be formed during the fermentation process. These by-products have the characteristics of being both fat-soluble and water-soluble, and it is impossible to remove them by this method, and they will eventually remain in the finished product.

[0006] (2) Column chromatography

[0007] Column chromatography is a method of separation by selecting a suitable stationary phase and eluent according to the different polarities of the material components. The advantages of this method are that under suitable conditions, theoretically a complete separation effect can be achieved, and industrial equipment is relatively mature. The disadvantages are that the investment in industrial equipment is too large. Under the condition of achieving the same processing capacity, it is at least 10 times higher than the extraction method. Second, it is very difficult to achieve an ideal separation state in industrial applications because there are many by-products in the rhamnolipid fermentation broth, and there are too many components with similar polarities. It is impossible to achieve an ideal hardware condition at the laboratory level by switching adsorption materials of various materials. Summary of the Invention

[0008] The purpose of the present invention is to overcome the above problems existing in the traditional technology, and provide an industrial purification method for rhamnolipids, which takes into account cost, efficiency, and separation effect from an industrial perspective, and has the characteristics of being easy to implement, easy to operate, and low emission.

[0009] To achieve the above technical objectives and reach the above technical effects, the present invention is realized through the following technical solutions:

[0010] An industrial purification method for rhamnolipids includes the following steps:

[0011] 1) Drying: Drying refers to the process of transforming the raw material into a powdery solid, i.e., dry powder. The raw material is rhamnolipid fermentation broth or bacterial residue thick slurry;

[0012] 2) Extraction: Use a sealable container with stirring. First, put in the dry powder, then add the organic solvent, stir at a speed of 30 - 50 rpm / min for 30 min, and let it stand for 2 - 3 h; Absorb and separate the upper clear liquid into a sealed container for later use; Then repeat adding the organic solvent for extraction 1 - 2 times, and transfer the clear liquid to the same sealed container and mix well;

[0013] 3) Ceramic membrane filtration: Use a 100 - 200 nm ceramic membrane to filter the extract, filtering out the impurities floating on the upper layer and suspended in the middle;

[0014] 4) Alkali precipitation: The filtered clear liquid is stored in a sealable container with a sight glass and stirrer, and the container needs to have an on-line pH detection function; Start stirring, and the stirring speed needs to be controlled at 5 - 10 rpm / min. Slowly add a high-concentration alkali solution, and the concentration of the alkali solution used needs to be ≥ 40%. Adjust the pH value of the clear liquid to 8.0 - 12.0; After the pH reaches the requirement, immediately stop stirring and let it stand for 0.5 - 1 h; Drain the alkali precipitate from the bottom of the tank, and make sure not to drain the upper liquid through the sight glass. After collecting the precipitates, adjust the pH to 7.0 - 8.0 with HCL for standby;

[0015] Start stirring and repeat the above steps 2 - 3 times, collect the alkali precipitates and keep the pH at 7.0 - 8.0;

[0016] 5) Nanofiltration membrane filtration: Add 2 - 4 times of water to the collected precipitate after alkali precipitation and stir for 10 - 20 min to dissolve. Use a nanofiltration membrane with a cut-off molecular weight of 150 - 300 Dal to filter, filtering out Na + or K + , CL - , OH - , small molecule water-soluble impurities and water; The pressure of the nanofiltration membrane high-pressure pump is maintained at 0.7 - 2.5 mPa, and stop filtering when the membrane effluent flow rate reaches 1 / 5 of the initial flow rate;

[0017] Repeat the above nanofiltration membrane filtration steps 2 - 3 times. For the last time, add pure water and stop filtering when the total volume of the feed liquid is 2 - 2.5 times the amount of the alkali precipitation aggregate to ensure the fluidity of the material for convenient discharging;

[0018] 6) Vacuum concentration: Concentrate the nanofiltration concentrate using a vacuum concentrator, control the vacuum degree at -0.06 - -0.08 MPa, and the temperature at 60 - 80 °C; Take samples during the concentration process and use the drying method to detect the solids. Stop concentration and discharge when the solids reach 45 - 55%, and the best is 48 - 52%;

[0019] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 1), when the raw material is the concentrated bacterial residue slurry, spray drying is carried out using a spray drying tower; for the rhamnolipid fermentation broth, due to the large liquid volume, it is first concentrated and dehydrated using a nanofiltration membrane with a cut-off molecular weight of 150 - 300 Dal. When the water removal amount reaches 40 - 50% of the total liquid volume, the dehydration is stopped; for the concentrated rhamnolipid fermentation broth, according to the calculation of the solid content and the content of pure active substances, a drying carrier is selectively added as a solid diluent to make the final dry powder active substance content between 25 - 40%.

[0020] Further, in the above-mentioned industrial purification method of rhamnolipid, the drying carrier is selected as inorganic salts, and the feed rate of the spray drying tower is adjusted to make the drying parameters stable at an inlet air temperature of 170 - 180 °C and an outlet air temperature of 100 - 120 °C; according to the combination of the feed rate and the inlet and outlet air temperatures, the water content of the finished product is controlled to be < 3%. After drying is completed, the dry powder is collected and stored in a sealed manner for later use.

[0021] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 1), when the raw material is the rhamnolipid fermentation broth, the general solid content of the rhamnolipid bacterial residue concentrated slurry is 30 - 40%, and it can be directly dried. Vacuum belt drying is carried out using a vacuum belt dryer, the equipment pressure ≤ -0.09 MPa, the temperature is controlled at 60 - 70 °C, the feed rate of the vacuum belt dryer is adjusted, the water content of the finished product is controlled to be < 3%, and after drying is completed, the dry powder is collected and stored in a sealed manner for later use.

[0022] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 2), an organic solvent is used to extract the dry powder, and the mass-volume ratio of the dry powder to the organic solvent is 1:2 - 6 g / mL, and the organic solvent is ethyl acetate or n-hexane.

[0023] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 3), the membrane pressure is controlled at 0.3 - 0.5 mPa during the filtration process, and the temperature does not exceed 50 °C.

[0024] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 4), the base is NaOH or KOH.

[0025] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 4), the pH value of the clear liquid is adjusted to 10.0 - 12.0.

[0026] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 5), the pressure of the nanofiltration membrane high-pressure pump is maintained at 0.8 - 1.0 mPa.

[0027] Further, in the above-mentioned industrial purification method of rhamnolipid, in step 6), when the solid content reaches 48 - 52%, the concentration is stopped and the product is discharged.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. Solid-phase extraction greatly reduces the amount of organic solvents used.

[0030] The present invention extracts the active ingredient of rhamnolipid from dry rhamnolipid fermentation broth powder or bacterial residue powder. In this extraction method, since the volume of the fermentation broth is greatly reduced to 1 / 8 - 1 / 10 of the original after drying, it is only necessary to extract with organic solvents 2 - 3 times, greatly reducing the overall amount of organic solvents used.

[0031] 2. Water-soluble proteins are completely removed.

[0032] Water-soluble protein impurities denature and aggregate to form large particles during the drying process and are more easily separated during the extraction process.

[0033] 3. Single-phase conversion, and two-phase soluble impurities are removed in one step.

[0034] The residual oil and fatty acids in the rhamnolipid fermentation broth are not soluble in water itself, but the two phases are miscible in the presence of surfactants and are difficult to remove. In addition, during the biological fermentation process, some organic nitrogen sources condense with fatty acids to form intermediate products. This intermediate product is soluble in both organic solvents and water and is not affected by pH, and is also a part that is difficult to remove during the rhamnolipid extraction process. However, in the method of the present invention, after extraction with organic solvents, only one step of alkali precipitation is required to leave the residual oil, fatty acids, and intermediate products in the organic phase, while glycolipids and a very small amount of water-soluble small molecules and salts are precipitated.

[0035] 4. The whole process has low liquid volume and low sewage discharge.

[0036] Due to the reduction of the overall treatment volume, volatile organic compounds and sewage are reduced by more than 10 times compared with the conventional organic solvent method.

[0037] 5. High separation efficiency

[0038] Both the organic solvent extraction process and the alkali precipitation process are very obvious and rapid, without the need for additional external force, and good separation can be achieved under static conditions.

[0039] 6. The industrial-grade overall recovery rate reaches over 70%.

[0040] For the organic solvent method and column chromatography method, their recovery rates are not easy to control, and the overall loss rate is between 30% - 50%. The method adopted by the present invention has low requirements for rhamnolipid dry powder, does not require a large amount of pretreatment process, can directly dry with bacteria, the total drying loss rate can be controlled within <10%, the total loss rate from extraction to alkali precipitation is <15%, and the total loss rate of nanofiltration and finished product concentration is <5%. The industrial-grade overall recovery rate can reach over 70%.

[0041] 7. Low comprehensive cost

[0042] Since the dry rhamnolipid dry powder contains ≤3% water and there is basically no process of transferring to the water phase, a large amount of organic solvent will not dissolve into the water during the extraction process, and the loss of the solvent is less than 0.03% of the original fermentation broth being processed, and the resulting loss cost can be ignored.

[0043] Because the concentration of the organic solvent in the sewage is low, the sewage can be directly discharged into the sewage treatment system without incurring a recovery cost and reducing the environmental protection treatment cost.

[0044] The present invention can not only extract using the dry powder of the rhamnolipid fermentation broth, but also extract using the thick slurry of the bacterial residue generated during the production process of industrial-grade crude rhamnolipid liquid extract. During the production process of this product, about 20-25% of the total fermentation broth volume of thick slurry of the bacterial residue will be generated. There is currently no way to further process the thick slurry of the bacterial residue and it can only be treated in a reduced volume and then enter the sewage treatment system. The thick slurry of the bacterial residue still contains 50-60 g / L of rhamnolipid content. After drying, rhamnolipid bacterial residue dry powder with a content of about 25% (about 250 g / kg) can be obtained. The rhamnolipid bacterial residue dry powder can be extracted using the process of the present invention, ultimately turning waste into treasure.

[0045] Of course, it is not necessary for any product implementing the present invention to simultaneously achieve all of the above advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for describing the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0047] Figure 1 It is the process flow diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0049] Example 1:

[0050] Use a tank of freshly fermented rhamnolipid fermentation broth to extract pure rhamnolipid.

[0051] (1) Drying

[0052] Use 30 m3 The fermentation broth of rhamnolipid was fermented in a fermenter with a liquid filling volume of 60%. After the fermentation reached the end point, the rhamnolipid content in the fermentation broth was measured to be 55.65 g / L, the solid content was 10.50%, and the pH after dilution by 10 times was 7.50. The fermentation broth was concentrated and dehydrated using a nanofiltration membrane with a cut-off molecular weight of 150 - 300 Dal. When the amount of water removed reached 9 t, the dehydration was stopped. 615 kg of NaCl was added as a carrier to the concentrated rhamnolipid fermentation broth and mixed evenly. The mixed material was transported to a spray drying tower for spray drying. The feeding rate was adjusted to 400 kg / h, and the drying parameters were set as an inlet air temperature of 175 °C and an outlet air temperature of 110 °C. Samples were taken and tested every 6 h during the process. The water content of the finished product was all < 3%. After drying was completed, the spray tower was cleaned. A total of 2305.6 kg of the finished product was collected, with a content of 39.98% and a total yield of effective substances of 92.04%. The finished product was sealed and packaged in kraft paper bags lined with moisture-proof bags, 25 kg per bag.

[0053] (2) Extraction

[0054] The dry powder was extracted using ethyl acetate, and the mass-volume ratio of dry powder to solvent was 1:4. The dry powder was put in, organic solvent was added, and it was stirred at a speed of 50 rpm / min for 30 min. After standing for 2 h, the layering was obvious. The upper clear liquid was sucked from the upper layer in the tank by a peristaltic pump and transferred to a storage tank for standby.

[0055] The second extraction was carried out with 2 times the solvent, and the third extraction was carried out with 1 times the solvent. The clear liquid was transferred to an alkali precipitation tank and mixed evenly. A total of 15800 L of the extraction liquid was collected.

[0056] (3) Ceramic membrane filtration

[0057] The extraction liquid was filtered using a 100 nm ceramic membrane. The set pressure was 0.4 mPa, and the outlet liquid flow rate was controlled at 18 GPM. The temperature was controlled not to exceed 50 °C during the process. After filtering all the materials, the filtered liquid was returned to the alkali precipitation tank for standby.

[0058] (4) Alkali precipitation

[0059] The stirring of the alkali precipitation tank was started, and the stirring speed was controlled at 5 rpm / min. The prepared 40% concentration NaOH alkali solution was slowly added. Through the on-line pH meter, the pH value of the material liquid was adjusted to 9.0. After the pH reached the requirement, the stirring was stopped, and it was left standing for 0.5 h. The alkali precipitate was discharged from the bottom of the tank to the material liquid storage tank, and the pH of the collected alkali precipitate was adjusted to 7.5 with 1:1 diluted HCL for standby.

[0060] Start stirring, add lye to adjust the pH value of the feed liquid to 10.0. After the pH reaches the requirement, stop stirring, let it stand for 1 h, discharge the alkali precipitate from the bottom of the tank to the feed liquid storage tank, and use 1:1 diluted HCL to adjust the pH of the collected alkali precipitate to 7.5. This step is repeated twice in total. A total of 850 L of alkali precipitate is obtained. The measured effective substance content is 91.18%, and the total effective substance yield at this stage is 77.37%.

[0061] (5) Nanofiltration membrane filtration

[0062] Add 3 times the volume of water to the finally collected alkali precipitate, with a total volume of 2550 L, and stir for 20 min to mix evenly. Filter using a nanofiltration membrane with a cut-off molecular weight of 150 - 300 Dal and a water flux of 2 t / h. The pressure of the nanofiltration membrane high-pressure pump is maintained between 0.8 - 1.0 mPa, and the initial flow rate is shown as 28 L / min. Stop filtering when the effluent flow rate reaches 6 L / min. Add 3 times the water again and repeat the filtration twice. Finally, add 3 times the pure water for filtration, and stop filtering when the total volume of the feed liquid remains 2000 L, and discharge the material for standby. Sampling shows that the effective substance content of the liquid is 38.0%, the solid content is 39.17%, and the total effective substance yield at this stage is 75.87%.

[0063] (6) Vacuum concentration

[0064] According to the calculation, vacuum decompression concentration is carried out on the nanofiltration membrane concentrate. It is expected to evaporate 500 kg of water, and the target finished product is close to 50% effective substance content. The vacuum concentrator controls the vacuum degree between -0.06 and -0.07 MPa, and starts concentration at a temperature between 60 and 70 °C. Start sampling and detecting the solid content when the condensate water in the condenser tower reaches 400 L. Stop concentration and discharge the material when the solid content reaches 51.38% after the second detection. The final discharged finished product is 1485 kg, the effective substance content is 49.81%, the product purity is 96.94%, and the final total effective substance yield is 73.84%.

[0065] Example 2:

[0066] Use the waste bacterial residue thick slurry of the rhamnolipid liquid crude product to extract pure rhamnolipid.

[0067] (1) Drying

[0068] Take 5000 L of waste bacterial residue thick slurry containing rhamnolipid liquid crude product. The rhamnolipid content is measured to be 50.37 g / L, the solids content is 35.81%, and the pH after dilution by 10 times is 7.65. Use a vacuum belt dryer with a water evaporation rate of 300 kg / h for drying. The vacuum pressure of the equipment is set at -0.09 MPa and the temperature is 65 °C. Adjust the feed rate to control the water content of the finished product to be <3%. If the water content is relatively high during the startup stage, it can be recycled to the original liquid for re-drying. Samples are taken every 4 h during the process to measure the water content. After drying, the average water content of the finished bacterial residue powder is 2.35%, meeting the requirements. A total of 1830 kg of finished product is obtained, with a content of 13.55%, and the total recovery rate of the active substance is 98.46%. The finished product is sealed and packaged in kraft paper bags with 25 kg inner lining moisture-proof bags.

[0069] (2) Extraction

[0070] Use ethyl acetate to extract the dry powder, and the mass-volume ratio of dry powder to solvent is 1:3. Put in the dry powder, add 3 times the organic solvent, stir at a speed of 40 rpm / min for 30 min, and let it stand for 3 h to separate into layers. Use a peristaltic pump to suck and separate the upper clear liquid from the upper layer in the tank to the storage tank for standby.

[0071] Extract for the second time with 2 times the solvent and for the third time with 2 times the solvent, and transfer the clear liquid to the alkali precipitation tank and mix well. A total of 12810 L of extraction liquid is collected.

[0072] (3) Ceramic membrane filtration

[0073] Use a 100 nm ceramic membrane to filter the extraction liquid, set the pressure at 0.4 mPa, and control the outlet flow rate at 16 GPM. During the process, control the temperature not to exceed 50 °C. After filtering all the materials, return the filtered liquid to the alkali precipitation tank for standby.

[0074] (4) Alkali precipitation

[0075] Start the stirring in the alkali precipitation tank, control the stirring speed at 8 rpm / min, and slowly add the prepared 40% concentration NaOH alkali solution. Adjust the pH value of the material liquid to 9.5 by observing the on-line pH meter. After the pH reaches the requirement, stop stirring, let it stand for 1 h, discharge the alkali precipitate from the bottom of the tank to the material liquid storage tank, and use 1:1 diluted HCL to adjust the pH of the collected alkali precipitate to 7.5 for standby.

[0076] Repeat the alkali precipitation step three times, adjust the pH to 10, 11, and 12 respectively. Let it stand for 1 h each time, and also adjust the pH of the collected alkali precipitate to 7.5 each time. Finally, a total of 238 L of alkali precipitate is obtained. The measured active substance content is 85.36%, and the total active substance recovery rate at this stage is 80.66%.

[0077] (5) Nanofiltration membrane filtration

[0078] Add water with a volume three times that of the finally collected and aggregated alkali precipitate, with a total volume of 720 L, and stir for 20 min to mix evenly. Filter using a nanofiltration membrane with a cut-off molecular weight of 150 - 300 Dal and a water flux of 300 L / h. Maintain the pressure of the nanofiltration membrane high-pressure pump between 0.8 - 0.9 mPa. The initial flow rate is shown as 4.5 L / min, and stop filtering when the effluent flow rate reaches 1 L / min. Add water three times again and repeat the filtration twice. Finally, add pure water three times for filtration, and stop filtering when the total volume of the feed liquid remains 480 L, and keep the discharged material for standby. Sampling shows that the effective substance content of the liquid is 41.26%, the solid content is 43.78%, and the total effective substance yield at this stage is 78.63%.

[0079] (6) Vacuum concentration

[0080] According to the calculation, perform vacuum decompression concentration on the nanofiltration membrane concentrate. It is expected to evaporate 400 kg of water, and the target finished product has an effective substance content of 50%. Start the concentration of the vacuum concentrator with the vacuum degree controlled between -0.07 MPa and the temperature between 65 - 70 °C. Start sampling and detecting the solids when the condensate water in the condenser tower reaches 350 L, and stop the concentration and discharge the material when the solids reach 49.68% after the third sampling and detection. The final discharged finished product is 410 kg, the effective substance content is 48.10%, the product purity is 96.81%, and the final total effective substance yield is 78.30%.

[0081] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to only the specific implementation manners. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. An industrial purification method of rhamnolipid, characterized in that, It includes the following steps: 1) Drying: Drying refers to the process of transforming raw materials into powdered solids, i.e., dry powder. The raw materials are rhamnolipid fermentation broth or concentrated slurry of bacterial residues. 2) Extraction: Use a sealable container with stirring. First, put in the dry powder, then add an organic solvent, stir at a speed of 30 - 50 rpm / min for 30 min, and let it stand for 2 - 3 h; Absorb and separate the upper clear liquid into a sealed container for later use; Then repeat adding the organic solvent for extraction 1 - 2 times, and transfer the clear liquid to the same sealed container for mixing. 3) Ceramic membrane filtration: Use a 100 - 200 nm ceramic membrane to filter the extraction liquid to filter out the impurities floating on the upper layer and suspended in the middle. 4) Alkali precipitation: The filtered clear liquid is stored in a sealed container with a sight glass and stirrer. The container needs to have an online pH detection function; Start stirring, and the stirring speed needs to be controlled at 5 - 10 rpm / min. Slowly add a high-concentration alkali solution. The concentration of the alkali solution used needs to be ≥40%, and adjust the pH value of the clear liquid to 8.0 - 12.0; After the pH reaches the requirement, immediately stop stirring and let it stand for 0.5 - 1 h; Drain the alkali precipitate from the bottom of the tank body. Through the sight glass, make sure not to drain the upper liquid. After collecting the precipitates, adjust the pH to 7.0 - 8.0 with HCL for standby. Start stirring and repeat the above steps 2 - 3 times, summarize the alkali precipitates and keep the pH at 7.0 - 8.

0. 5) Nanofiltration membrane filtration: Add 2 - 4 times of water to the precipitate aggregate collected after alkali precipitation and stir for 10 - 20 min to dissolve it. Use a nanofiltration membrane with a cut-off molecular weight of 150 - 300 Dal for filtration; The pressure of the nanofiltration membrane high-pressure pump is maintained at 0.7 - 2.5 mPa. When the membrane effluent flow rate reaches 1 / 5 of the initial flow rate, stop filtration. Repeat the above nanofiltration membrane filtration steps 2 - 3 times. For the last time, add pure water and stop filtration when the total volume of the feed liquid is 2 - 2.5 times the amount of the alkali precipitation aggregate to ensure the fluidity of the material for convenient discharging. 6) Vacuum concentration: Concentrate the nanofiltration concentrate using a vacuum concentrator, control the vacuum degree at -0.06 - -0.08 MPa, and the temperature at 60 - 80 °C; During the concentration process, take samples and use the drying method to detect the solids. When the solids reach 45 - 55%, stop concentration and discharge the material.

2. The industrial purification method of rhamnolipid according to claim 1, wherein: In step 1), when the raw material is concentrated slurry of bacterial residues, spray drying is carried out using a spray drying tower; First, use a nanofiltration membrane with a cut-off molecular weight of 150 - 300 Dal for concentration and dehydration. When the water removal amount reaches 40 - 50% of the total liquid volume, stop dehydration; For the concentrated rhamnolipid fermentation broth, calculate according to the solids and pure active ingredient content, and selectively add a drying carrier as a solid diluent to make the final dry powder active ingredient content between 25 - 40%.

3. The industrial purification method of rhamnolipid according to claim 2, wherein: Select inorganic salts as the drying carrier, adjust the feed rate of the spray drying tower to make the drying parameters stable at an inlet air temperature of 170 - 180 °C and an outlet air temperature of 100 - 120 °C; According to the coordination of the feed rate and the inlet and outlet air temperatures, control the water content of the finished product <3%. After drying, collect the dry powder and store it sealed for later use.

4. The industrial purification method of rhamnolipid according to claim 1, characterized in that: In step 1), when the raw material is the rhamnolipid fermentation broth, vacuum belt drying is carried out using a vacuum belt dryer. The equipment pressure is ≤ -0.09 MPa, the temperature is controlled at 60 - 70 °C, the feeding rate of the empty belt dryer is adjusted, and the water content of the finished product is controlled to be < 3%. After drying, the dry powder is collected and stored sealed for later use.

5. The industrial purification method of rhamnolipid according to claim 1, characterized in that: In step 2), the dry powder is extracted with an organic solvent. The mass-volume ratio of the dry powder to the organic solvent is 1:2 - 6 g / mL, and the organic solvent is ethyl acetate or n-hexane.

6. The industrial purification method of rhamnolipid according to claim 1, characterized in that: In step 3), during the filtration process, the membrane pressure is controlled at 0.3 - 0.5 mPa, and the temperature does not exceed 50 °C.

7. The industrial purification method of rhamnolipid according to claim 1, characterized in that: In step 4), the base is NaOH or KOH.

8. The industrial purification method of rhamnolipid according to claim 1, characterized in that: In step 4), the pH value of the clear liquid is adjusted to 10.0 - 12.

0.

9. The industrial purification method of rhamnolipid according to claim 1, characterized in that: In step 5), the pressure of the nanofiltration membrane high-pressure pump is maintained at 0.8 - 1.0 mPa.

10. The industrial purification method of rhamnolipid according to claim 1, characterized in that: In step 6), when the solid content reaches 48 - 52%, the concentration is stopped and the product is discharged.

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