Reextraction process of threonine mother liquor

Abstract

The invention belongs to the technical field of biology, and discloses a threonine mother liquor re-extraction process which comprises the following steps: adjusting the concentration of threonine mother liquor, adding ethanol, cooling, settling and crystallizing, adding water into crystals for dissolving, decolorizing with activated carbon, filtering, collecting filtrate, decolorizing again, filtering, collecting feed liquid, and sending the feed liquid into a single-effect crystallization pot for settling and crystallizing threonine, and collecting supernate for recovering ethanol. The method provided by the invention realizes resource cyclic utilization, improves yield, reduces energy consumption and waste liquid discharge, has the characteristics of high efficiency, environmental protection and strong economy, and is suitable for industrial continuous production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of biotechnology, and particularly relates to a re-extraction process of threonine mother liquor. BACKGROUND

[0002] L-threonine is one of the eight essential amino acids for human body, and is an important component of protein, has the effect of restoring fatigue and promoting growth and development, and is widely used in food, feed and medical fields. With the rapid growth of the use in chemical and biochemical, feed additives and food additives, etc., threonine has become the third largest amino acid after lysine and methionine.

[0003] In recent years, L-threonine has become one of the main bottlenecks of animal production performance. It is a necessary amino acid for growth, promotes the production of mucus in the intestinal tract of animals, and plays an important role in food digestion. For animal growth and development, good balance of each essential amino acid is very important, however, the amino acid content of most feed raw materials such as corn or wheat is not balanced, by adding L-threonine, the coordination of various amino acid proportions in feed can be increased, the quality of feed can be improved, and unnecessary waste of resources can be effectively reduced.

[0004] In the pharmaceutical industry, the position of L-threonine is also very important. As an essential amino acid in the human body, L-threonine plays an important role in human metabolism, can improve the nutritional status, promote the growth and development of the body, and improve the body's immunity. For patients with oral injury or receiving surgery, sometimes they cannot ingest enough nutrients, so they can obtain the necessary nutritional ingredients by adding amino acid injection containing L-threonine, and at the same time, enhance the body's vitality, which is also of great help to the recovery of wounds.

[0005] In recent years, with the development of the management mode of circular economy, enterprises are exploring the sustainable recycling, maximizing the use of resources, protecting the environment, increasing the added value of products and the competitiveness of enterprises, so as to achieve the win-win of economic benefits and ecological environment. The recovery of threonine from mother liquor has great economic value. Reasonable use of mother liquor for process recycling is the inevitable result of the advanced and reasonable threonine production process. The treatment of mother liquor is the key to the yield of purification, mainly in its special physical and chemical indicators. There are great differences between threonine production and glutamic acid and lysine production in the extraction and purification process in the later stage of production. Biological fermentation method is widely used in amino acid production, and the bacteria remain in the fermentation broth, becoming part of the organic pollution source of the fermentation waste mother liquor. The bacterial protein contains rich protein, and the amino acid extraction process and the composition of the waste mother liquor are different from other nutrients. Threonine production process is mostly based on corn syrup and molasses as fermentation nitrogen source. Because corn syrup contains rich amino acids, reducing sugars, phosphorus, trace elements and growth hormone and other nutrients. Through threonine conversion bacteria fermentation, the fermentation broth is filtered by ceramic membrane equipment to remove the bacterial protein and other impurities, but the ceramic membrane filtration treatment intercepts only about 20% of the volume of the fermentation broth. After filtration, the supernatant is concentrated, centrifuged, dried, sieved and packaged, and threonine products are produced. A large amount of waste mother liquor is produced in this process, which contains threonine, impurity amino acid, protein, residual sugar and inorganic salt. Selling it to a feed additive factory will reduce the value of the mother liquor; directly discharging it into the environment will cause great waste and pollution. How to reasonably dispose of the waste mother liquor is a difficult problem.

[0006] At present, the treatment methods of threonine mother liquor are as follows: (1) the mother liquor directly enters the sewage treatment system, resulting in that the total yield of threonine extraction is less than 82%, so the production cost is high; (2) the mother liquor is treated by ion exchange system, and then concentrated and crystallized to extract threonine again, and the total yield of threonine is generally about 93%. The method has high consumption of liquid ammonia and sulfuric acid, low concentration of analysis liquid, and high cost in the whole production process. (3) the relatively advanced chromatographic separation method is adopted, the recovery rate of threonine in the mother liquor can reach 88%, and the total yield can reach about 94%. However, the chromatographic separation method has large one-time investment and long cost recovery period; at the same time, the method needs to pretreat the raw materials, which will consume a large amount of deionized water, and the threonine content of the obtained extraction liquid is low, and a large amount of electricity and gas will be consumed in the concentration process, so the total production cost is slightly lower than that of the former two methods. SUMMARY

[0007] The present application provides a threonine mother liquor re-extraction process to improve the extraction yield of threonine and reduce the burden of sewage treatment, thereby increasing the economic benefits of enterprises.

[0008] The application is realized by the technical scheme as follows.

[0009] The re-extraction process of threonine mother liquor comprises the following steps: adjusting the concentration of threonine mother liquor, adding ethanol, cooling and settling crystallization, dissolving the crystals with water, decolorizing with activated carbon, filtering, collecting the filtrate, decolorizing again, filtering and collecting the material liquid to send into a single-effect crystallization kettle for settling crystallization of threonine, and collecting the supernatant for recycling of ethanol.

[0010] Further, it comprises the following steps: 1) A certain amount of threonine mother liquor solution is added into a crystallization tank, and the concentration thereof is adjusted to 10-20 g / dL, and the temperature is 30-50℃; 2) The stirring is started, and ethanol solution is slowly added into the crystallization tank, the flow rate of the ethanol solution is controlled to be 20-50% of the volume of the material liquid per hour, and the amount of ethanol used is 50-150% of the volume of the solution; 3) The solution is slowly cooled, and the stirring is stopped after the temperature is reduced to 5-20℃, and the settling is performed for 3-8h; 4) After the crystallization, the material liquid is separated into the settled substance and the waste mother liquor by natural settling, and the settled substance is the threonine wet crystal; 5) The threonine wet crystal particles obtained in step 4) are dissolved with water and pumped into a decolorizing tank for decolorizing treatment, the decolorizing tank is filled with powdered activated carbon, the temperature in the decolorizing tank is controlled to be 50-60℃, the pH is controlled to be 5-6, the Baume degree is controlled to be 10-12, after decolorizing for 30 minutes, the filtration is performed, the filtrate is collected, secondary decolorizing is performed, and finally the threonine is extracted by settling crystallization in a single-effect crystallization kettle; 6) The supernatant obtained in step 5) is used for recycling of the alcohol in the mother liquor by distillation, and the obtained alcohol solution is reused in the alcohol flow adding system.

[0011] Preferably, the addition amount of the powdered activated carbon is 1%.

[0012] Preferably, the concentration of the ethanol solution in step 2) is more than 95%.

[0013] Preferably, in step 3), the settling time is 6h.

[0014] Preferably, the amount of the ethanol solution used in step 2) is 100% of the volume of the solution. DETAILED DESCRIPTION

[0015] In order to make the person skilled in the art better understand the technical solutions in the present application, the present application will be described more clearly and completely below in combination with specific embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0016] Embodiment 1 A re-extraction process of threonine mother liquor, comprising the following steps: A certain amount of threonine mother liquor solution is added to the crystallization tank, and the concentration is adjusted to 10-20 g / dL, and the temperature is 30-50℃.

[0017] Start stirring, slowly add 95% or more ethanol solution to the crystallization tank, control the flow rate of the ethanol solution to be 20-50% of the volume of the feed liquid per hour, and the amount of ethanol used is 50-150% of the volume of the solution.

[0018] Start slow cooling of the solution with cooling water, stop stirring when the temperature drops to 5-20℃, and stand for 3-8h.

[0019] After crystallization, the feed liquid is separated into sediment and mother liquor by natural sedimentation, and the sediment is threonine crystals.

[0020] The crystal particles obtained in the above process are dissolved in water and pumped into a decolorizing tank for decolorization treatment. The decolorizing tank contains 1% powdered activated carbon, the temperature in the decolorizing tank is controlled at 50-60℃, the pH is 5-6, and the Baumé degree is 10-12. After 30 minutes of decolorization, the feed liquid is pumped into a plate-type closed filter for filtration. The flow rate of the feed liquid through the filter is fast at first and then slow. After filtration, the filter cake is dried with air or steam. The plate-type closed filter is periodically vibrated to remove the carbon by using the vibrator inside the filter. The removed carbon is regenerated at high temperature and reused. The filtrate from the filter is pumped into a carbon column for further decolorization and impurity removal treatment. Finally, the feed liquid is sent to a single-effect crystallization kettle for threonine extraction.

[0021] The supernatant after sedimentation is used to recover alcohol from the mother liquor by distillation column. The obtained alcohol solution is reused in the alcohol flow system, thereby greatly reducing the production cost.

[0022] After recovering alcohol by distillation column, the remaining bottom material is finally sent to the environmental protection workshop for sewage treatment.

[0023] The threonine mother liquor after the above treatment has high crystallization yield, the total extraction yield of threonine reaches more than 95%, and all indicators of the threonine product meet the national standards.

[0024] The present application reduces the solubility of threonine in the solution by adding alcohol, thereby precipitating threonine crystals. Unlike high-temperature concentration crystallization, the present method can reduce the solubility of threonine in the mother liquor at a lower temperature to recover threonine, greatly improving the working environment of workers. Compared with the traditional process, the present application greatly reduces production costs, is easy to operate, and has stable and reliable product quality. The present application recovers threonine from threonine mother liquor, improves the extraction yield of threonine, meets the requirements of resource comprehensive utilization, energy saving and emission reduction, reduces waste liquid discharge, reduces the burden of sewage treatment, and brings huge economic and environmental benefits.

[0025] Example 1 A threonine mother liquor re-extraction process, comprising the following steps: A certain amount of threonine mother liquor solution is added to the crystallization tank, and the concentration is adjusted to 10 g / dL, and the temperature is 45℃.

[0026] Start stirring, slowly add 95% ethanol solution to the crystallization tank, control the flow rate of the ethanol solution to be 20% of the volume of the solution per hour, and the amount of ethanol used is 60% of the volume of the solution.

[0027] Start slow cooling the solution with cooling water, stop stirring when the temperature drops to 5℃, and stand for 3h.

[0028] After crystallization, the feed solution is separated into sediment and mother liquor by natural sedimentation, and the sediment is threonine crystals.

[0029] The crystal particles obtained in the above process are dissolved in water and pumped into a decolorizing tank for decolorization treatment. The decolorizing tank contains 1% powdered activated carbon, the temperature in the decolorizing tank is controlled at 50℃, the pH is 5, and the Baume degree is 10. After 30 minutes of decolorization, the feed solution is pumped into a plate-type closed filter for filtration. The flow rate of the feed solution through the filter is first fast and then slow. After filtration, the filter cake is blown dry with steam. The plate-type closed filter is periodically vibrated with the vibrator inside the filter to remove the carbon. The removed carbon is regenerated at high temperature and reused. The filtrate from the filter is pumped into a carbon column for further decolorization and impurity removal treatment. Finally, the feed solution is sent to a single-effect crystallization kettle for threonine extraction.

[0030] The supernatant after sedimentation is recovered by distillation to recover the alcohol in the mother liquor, and the obtained alcohol solution is reused in the alcohol flow system, thereby greatly reducing the production cost.

[0031] After recovering the alcohol by distillation, the remaining bottom material is finally sent to the environmental protection workshop for sewage treatment.

[0032] The threonine mother liquor after the above treatment has high crystallization yield, and the total extraction yield of threonine reaches more than 95%, and all indicators of the threonine product meet the national standards.

[0033] The present application reduces the solubility of threonine in solution by adding alcohol, thereby precipitating threonine crystals. Unlike high-temperature concentration crystallization, the present method can reduce the solubility of threonine in the mother liquor at a lower temperature to recover threonine, greatly improving the working environment of workers. Compared with the traditional process, the present application greatly reduces production costs, is easy to operate, and produces stable and reliable product quality. The recovery of threonine from threonine mother liquor improves the extraction yield of threonine, meets the requirements of resource comprehensive utilization, energy saving and emission reduction, reduces waste liquid discharge, reduces the burden of sewage treatment, and brings huge economic and environmental benefits.

[0034] Example 2 A threonine mother liquor re-extraction process, comprising the following steps: A certain amount of threonine mother liquor solution is added to the crystallization tank, and the concentration is adjusted to 20 g / dL, and the temperature is 50°C.

[0035] Start stirring, slowly add 98% ethanol solution to the crystallization tank, control the addition rate of ethanol solution to be 40% of the volume of the solution per hour, and the amount of ethanol used is 120% of the volume of the solution.

[0036] Start slow cooling of the solution with cooling water, stop stirring when the temperature drops to 10°C, and stand for 5 hours.

[0037] After crystallization, the feed solution is separated into sediment and mother liquor by natural sedimentation, and the sediment is threonine crystals.

[0038] The crystal particles obtained in the above process are dissolved in water and pumped into a decolorization tank for decolorization treatment. The decolorization tank contains 1% powdered activated carbon, the temperature in the decolorization tank is controlled at 55°C, the pH is 5.5, and the Baume degree is 11. After 30 minutes of decolorization, the feed solution is pumped into a plate-type closed filter for filtration. The flow rate of the feed solution through the filter is first fast and then slow. After filtration, the filter cake is dried with air or steam. The plate-type closed filter is periodically vibrated with the vibrator inside the filter to remove the carbon. The removed carbon is regenerated at high temperature and reused. The filtrate from the filter is pumped into a carbon column for further decolorization and impurity removal treatment. Finally, the feed solution is sent to a single-effect crystallization kettle for threonine extraction.

[0039] The supernatant after sedimentation is recovered by distillation column to recover alcohol in the mother liquor. The obtained alcohol solution is reused in the alcohol addition system, thereby greatly reducing the production cost.

[0040] After recovering alcohol by distillation column, the remaining bottom material is finally sent to the environmental protection workshop for sewage treatment.

[0041] The threonine mother liquor after the above treatment has high crystallization yield, the total extraction yield of threonine reaches more than 95%, and all indicators of the threonine product meet the national standards.

[0042] Example 3 A re-extraction process of threonine mother liquor, comprising the following steps: A certain amount of threonine mother liquor solution is added into a crystallization tank, and the concentration thereof is adjusted to 15 g / dL, and the temperature is 40℃.

[0043] Stirring is started, and 100% ethanol solution is slowly added into the crystallization tank, and the flow rate of the ethanol solution is controlled to be 50% of the volume of the solution per hour, and the amount of ethanol used is 100% of the volume of the solution.

[0044] Cooling water is started to slowly cool the solution, and when the temperature is reduced to 12℃, stirring is stopped, and the solution is allowed to settle for 6 hours.

[0045] After crystallization, the solution is separated into a precipitate and a mother liquor by natural settling, and the precipitate is threonine crystals.

[0046] The crystal particles obtained in the above process are dissolved in water and pumped into a decolorization tank for decolorization treatment, the decolorization tank is filled with 1% powdered activated carbon, the temperature in the decolorization tank is controlled to be 60℃, the pH is controlled to be 5, and the Baume degree is controlled to be 12, after 30 minutes of decolorization, the solution is pumped into a plate-type closed filter for filtration, the flow rate of the solution through the filter is first fast and then slow, after filtration, the filter cake is dried by air or steam, the plate-type closed filter is periodically vibrated by the vibrator inside the filter to remove the carbon, the removed carbon is regenerated at high temperature and reused, and the filtrate from the filter is pumped into a carbon column for further decolorization and impurity removal treatment, and finally the solution is sent to a single-effect crystallization kettle for crystallization to extract threonine.

[0047] The supernatant after settling is used to recover alcohol in the mother liquor by distillation, and the obtained alcohol solution is reused in the alcohol flow addition system, thereby greatly reducing the production cost.

[0048] After the alcohol is recovered by distillation, the remaining bottom material is finally sent to an environmental protection workshop for sewage treatment.

[0049] The threonine mother liquor after the above treatment has a high crystallization yield, the total extraction yield of threonine reaches more than 95%, and various indexes of the threonine product meet the national standards.

[0050] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed with the preferred embodiment as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the disclosed technical content without departing from the technical solution of the present application, and the equivalent embodiments with equivalent changes are obtained. Any simple modification, equivalent change and modification of the above embodiments based on the technical essence of the present application are within the scope of the technical solution of the present application.

Claims

1. A process for re-extraction of threonine mother liquor, comprising the following steps: adjusting the concentration of threonine mother liquor, adding ethanol, cooling and allowing crystals to settle, dissolving the crystals in water, decolorizing with activated carbon, filtering, collecting the filtrate, decolorizing again, filtering and collecting the liquid and sending it to a single-effect crystallization pot to settle and crystallize threonine, and collecting the supernatant for ethanol recovery.

2. The re-extraction process according to claim 1, comprising the following steps: 1) Add a certain amount of threonine mother liquor solution to the crystallization tank, adjust its concentration to 10-20 g / dL, and keep the temperature at 30-50℃; 2) Start stirring and slowly add ethanol solution to the crystallization tank, controlling the flow rate of ethanol solution to be 20-50% of the volume of the material added per hour, and the amount of ethanol used to be 50-150% of the solution volume; 3) Slowly cool the solution down until the temperature drops to 5-20℃, then stop stirring and let it stand for 3-8 hours to settle. 4) After crystallization, the liquid material is separated into sediment and waste mother liquor by natural sedimentation. The sediment is wet threonine crystals. 5) Dissolve the threonine wet crystal particles obtained in step 4) in water and pump them into a decolorization tank for decolorization. The decolorization tank is filled with powdered activated carbon. Control the temperature in the decolorization tank at 50℃-60℃, pH at 5-6, and Baume degree at 10-12. After decolorization for 30 minutes, filter, collect the filtrate, perform a second decolorization, and finally send it to a single-effect crystallization pot for precipitation crystallization to extract threonine. 6) The supernatant obtained in step 5 is used to recover the alcohol from the mother liquor using a distillation column, and the resulting alcohol solution is then reused in the alcohol feed system.

3. The process according to claim 2, characterized in that, The amount of powdered activated carbon added is 1%.

4. The process according to claim 2, characterized in that, The concentration of the ethanol solution in step 2) is above 95%.

5. The process according to claim 2, characterized in that, In step 3), the settling time is 6 hours.

6. The process according to claim 2, characterized in that, The amount of ethanol solution used in step 2) is 100% of the solution volume.