Method for producing lactamide by using carbon dioxide

Abstract

The invention belongs to the technical field of synthesis of organic compounds, and particularly relates to a method for producing lactamide by using carbon dioxide. According to the method for preparing the lactamide, provided by the invention, a large amount of lactamide can be obtained only by utilizing the urea and the special lactobacillus for fermentation culture, so that the preparation cost of the lactamide is reduced. Furthermore, the urea can be prepared through the reaction of the carbon dioxide and the ammonia gas, that is, the carbon dioxide can be recycled to prepare the urea, and then the lactamide is prepared by adopting the method, so that the carbon emission is greatly reduced, the recycling problem of the carbon dioxide is effectively solved, and a new way is developed for the cyclic utilization of carbon resources.

Description

Technical Field

[0001] This invention belongs to the field of organic compound synthesis technology, and specifically relates to a method for producing lactamide using carbon dioxide. Background Technology

[0002] Lactamide is a skin and hair conditioning agent with moisturizing and antistatic properties. It is listed in the "Catalogue of Used Cosmetic Raw Materials" and is widely used in high-end toiletries, personal care products, and makeup. Grafted lactamide derivatives can also be used as pesticides and emulsifiers. The chemical synthesis of lactamide and its derivatives uses ethyl lactate, a non-renewable petrochemical resource, as a raw material. The process involves cooling the lactamide to below -78°C, adding liquid ammonia, and then heating it to room temperature in a pressure vessel. This process requires extensive refrigeration equipment, consumes a great deal of energy, and releases large amounts of ammonia as a byproduct, causing incalculable environmental pollution.

[0003] Therefore, there is an urgent need to develop a low-cost, more environmentally friendly method for preparing lactamide. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, one object of this invention is to provide a method for preparing lactamide, which only requires fermentation culture of urea and specific lactobacilli to obtain large quantities of lactamide, thus reducing the cost of lactamide preparation. Furthermore, urea can be produced by reacting carbon dioxide and ammonia, meaning that carbon dioxide can be recycled to prepare urea, and then lactamide can be prepared using the above method. This significantly reduces carbon emissions, effectively solves the problem of carbon dioxide recycling, and opens up new avenues for the circular utilization of carbon resources.

[0005] Therefore, the first aspect of this invention provides the use of a microorganism or an agent containing said microorganism in the preparation of lactamide. In some embodiments of this invention, the microorganism is *Limosilactobacillus reuteri*, deposited on May 29, 2024, at the Guangdong Provincial Microbial Culture Collection Center, with accession number GDMCC NO: 64700. The inventors have discovered that adding urea to the culture medium of the aforementioned *Limosilactobacillus reuteri* PDO / LA-3 can prepare large quantities of lactamide, and this method significantly reduces the cost of lactamide preparation.

[0006] A second aspect of the present invention provides a method for preparing lactamide. In some embodiments of the present invention, the method includes:

[0007] Urea is mixed with a culture medium containing microorganisms and fermented to prepare lactamide.

[0008] The microorganism in question is *Limosilactobacillus reuteri*, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on May 29, 2024, with accession number GDMCC NO: 64700.

[0009] The culture medium contains glucose.

[0010] The inventors discovered that the aforementioned *Lactobacillus reuteri* PDO / LA-3 can decompose glucose to obtain acetic acid during fermentation culture. Acetic acid can then react with urea in the culture medium to prepare pyruvamide. Pyruvamide is then catalyzed to obtain lactamide under the action of pyruvate kinase expressed by *Lactobacillus reuteri* PDO / LA-3.

[0011] In some embodiments of the present invention, the urea is prepared by reacting carbon dioxide and ammonia.

[0012] This invention utilizes a probiotic fermentation method to efficiently convert carbon dioxide into high-value-added lactamide, effectively solving the problem of carbon dioxide recycling and opening up new avenues for the circular use of carbon resources.

[0013] In some embodiments of the present invention, the fermentation culture is carried out at a temperature of 32-40°C for a time of 12-72 hours.

[0014] The inventors discovered that under these fermentation conditions, the yield of lactamide could be further increased.

[0015] In some preferred embodiments of the present invention, the fermentation culture is carried out at a temperature of 36-38°C for 45-50 hours.

[0016] In some more preferred embodiments of the present invention, the fermentation culture is carried out at a temperature of 37°C for a time of 48 hours.

[0017] In some embodiments of the present invention, the concentration of urea in the culture medium is 10-50 g / L during fermentation culture.

[0018] In some preferred embodiments of the present invention, the concentration of urea in the culture medium is 35-45 g / L during fermentation culture.

[0019] In some more preferred embodiments of the present invention, the concentration of urea in the culture medium is 40 g / L during fermentation culture.

[0020] In some embodiments of the present invention, the pH of the culture medium is 6-8.

[0021] In some preferred embodiments of the present invention, the pH of the culture medium is 7-8.

[0022] In some embodiments of the present invention, the concentration of glucose in the culture medium is 10-30 g / L.

[0023] In some embodiments of the present invention, the method further includes:

[0024] The fermentation broth containing lactamide obtained from fermentation culture is separated and purified in order to obtain the final product lactamide.

[0025] In some embodiments of the present invention, the separation and purification steps include: centrifugation, decolorization, filtration, evaporation, and crystallization.

[0026] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0028] Figure 1 The reaction mechanism of the method for preparing lactamide provided by the present invention is shown;

[0029] Figure 2 The 1H NMR spectrum of the product lactamide in the method for preparing lactamide according to one embodiment of the present invention is shown. 1 H-NMR spectrum. Detailed Implementation

[0030] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0031] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0032] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] To facilitate understanding of the invention, certain technical and scientific terms are specifically defined below. Unless otherwise expressly defined elsewhere in this document, all other technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] In this document, the terms “comprising” or “including” are open-ended expressions, meaning that they include the contents specified in this invention, but do not exclude other aspects.

[0035] In this document, the terms “optionally,” “optionally,” or “optionally” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0036] According to a specific embodiment of the present invention, the present invention provides the use of a microorganism or an inoculum containing said microorganism in the preparation of lactamide. The microorganism is *Limosilactobacillus reuteri*, deposited on May 29, 2024, at the Guangdong Provincial Microbial Culture Collection Center, accession number GDMCC NO: 64700, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, postal code: 510070. The inventors have discovered that adding urea to the culture medium of the above-mentioned *Limosilactobacillus reuteri* PDO / LA-3 can prepare large quantities of lactamide, which significantly reduces the cost of lactamide preparation.

[0037] The screening process for Lactobacillus reuteri PDO / LA-3 provided by this invention refers to patent CN202411202722.5.

[0038] According to a specific embodiment of the present invention, the present invention provides a method for preparing lactamide, comprising:

[0039] Urea is mixed with a culture medium containing microorganisms and fermented to prepare lactamide.

[0040] The microorganism in question is *Limosilactobacillus reuteri*, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on May 29, 2024, with accession number GDMCC NO: 64700.

[0041] The culture medium contains glucose.

[0042] The inventors discovered that the aforementioned *Lactobacillus reuteri* PDO / LA-3, during fermentation culture, can decompose glucose to obtain acetic acid. Acetic acid can then react with urea in the culture medium to prepare pyruvamide. Pyruvamide, under the action of pyruvate kinase expressed by *Lactobacillus reuteri* PDO / LA-3, catalyzes the conversion to lactamide. The specific reaction route is described in [reference needed]. Figure 1 .

[0043] It should be noted that the inventors used previously screened specific *Lactobacillus reuteri* for fermentation culture and synthesized lactamide using urea. This is a novel approach to lactamide synthesis. There are no particular limitations on the fermentation conditions; however, the optimized fermentation conditions explored in this invention preferably yield higher lactamide yields. The examples and comparative examples provided below represent further optimizations of the novel method for preparing lactamide to achieve higher yields, and do not imply that the method is limited to the conditions described in the examples.

[0044] There are no particular restrictions on the composition of the culture medium used for fermentation; it can be any culture medium composition known in the art that is suitable for the fermentation culture of Lactobacillus reuteri.

[0045] According to a specific embodiment of the present invention, the culture medium for fermentation can be composed of: 10-40 g / L glucose, 8-12 g / L peptone, 6-10 g / L beef extract powder, 2-6 g / L yeast extract powder, 1-3 g / L dipotassium hydrogen phosphate, 3-6 g / L sodium acetate, 1-3 g / L diammonium hydrogen citrate, 0.1-0.3 g / L magnesium sulfate (MgSO4·7H2O), 0.02-0.05 g / L manganese sulfate (MnSO4·4H2O), 0.5-2 mL / L Tween-80, with the remainder being water.

[0046] According to a more specific embodiment of the present invention, the culture medium for fermentation can be composed of: 20 g / L glucose, 10 g / L peptone, 8 g / L beef extract powder, 4 g / L yeast extract powder, 2 g / L dipotassium hydrogen phosphate, 5 g / L sodium acetate, 2 g / L diammonium hydrogen citrate, 0.2 g / L magnesium sulfate (MgSO4·7H2O), 0.04 g / L manganese sulfate (MnSO4·4H2O), 1 mL / L Tween-80, and the remainder being water.

[0047] It should be noted that there are no particular restrictions on the source of urea in the method for preparing lactamide; it can be purchased directly or obtained through a reaction. According to a preferred embodiment of the present invention, the urea is prepared by reacting carbon dioxide and ammonia.

[0048] When urea is obtained by reacting carbon dioxide and ammonia in the method for preparing lactamide provided by the present invention, there are no particular restrictions on the conditions for the reaction of carbon dioxide and ammonia. All reaction conditions that can achieve urea synthesis are covered within the scope of protection of the present invention.

[0049] According to a specific embodiment of the present invention, urea can be obtained by the following method: industrial tail gas is pretreated by dehydrogenation and desulfurization, and the treated mixed gas containing carbon dioxide, carbon monoxide, oxygen, nitrogen and water vapor is compressed and cooled to 5-109 kPa and 30-50°C. The gas is then introduced into a high-pressure reactor at a molar ratio of carbon dioxide to liquid ammonia of 1:2-1:4 to carry out a synthesis reaction at a reaction temperature of 180-220°C and a reaction pressure of 12-16 MPa to obtain recovered gaseous urea.

[0050] With the global progress towards zero carbon emissions, product carbon footprint has become a key indicator of concern. Existing methods for preparing lactamide use alkyl lactate esters, which significantly reduce the product's carbon footprint by using glycerol, a recyclable carbon source. However, the reaction process still generates some carbon emissions and fails to achieve the goal of carbon reduction. This invention utilizes a probiotic fermentation method to efficiently convert carbon dioxide into high-value-added lactamide, effectively solving the problem of carbon dioxide recovery and utilization and opening up new avenues for the recycling of carbon resources.

[0051] According to a specific embodiment of the present invention, the fermentation culture is carried out at a temperature of 32-40°C for a time of 12-72 hours. Under these fermentation culture conditions, the yield of lactamide can be further improved.

[0052] According to a specific embodiment of the present invention, the fermentation temperature can be 32℃, 35℃, 37℃, 39℃, or 40℃; the fermentation time can be 12h, 20h, 30h, 40h, 50h, 60h, 70h, or 72h, etc., and all values ​​within the above ranges are covered within the protection scope of the present invention.

[0053] According to a preferred embodiment of the present invention, the fermentation culture is carried out at a temperature of 36-38°C for a time of 45-50 hours.

[0054] According to a more preferred embodiment of the present invention, the fermentation culture is carried out at a temperature of 37°C for a time of 48 hours.

[0055] According to a specific embodiment of the present invention, during fermentation, the concentration of urea in the culture medium is 10-50 g / L. It should be noted that the concentration of urea in the culture medium during fermentation can be 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, or 50 g / L; all values ​​within the above range are covered by the protection scope of the present invention.

[0056] According to a preferred embodiment of the present invention, during fermentation culture, the concentration of urea in the culture medium is 35-45 g / L.

[0057] According to a more preferred embodiment of the present invention, the concentration of urea in the culture medium is 40 g / L during fermentation culture.

[0058] According to a specific embodiment of the present invention, the pH of the culture medium is 6-8. For example, the pH of the culture medium can be 6, 6.5, 7, 7.5, or 8.

[0059] According to a preferred embodiment of the present invention, the pH of the culture medium is 7.5.

[0060] According to a specific embodiment of the present invention, the concentration of glucose in the culture medium is 10-30 g / L.

[0061] According to a preferred embodiment of the present invention, the present invention provides a method for preparing lactamide, comprising:

[0062] Urea is mixed with a culture medium used for fermenting microorganisms and then fermented to prepare lactamide.

[0063] The microorganism in question is *Limosilactobacillus reuteri*, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on May 29, 2024, with accession number GDMCC NO: 64700.

[0064] The culture medium contains 10-30 g / L glucose, and the urea is prepared by reacting carbon dioxide and ammonia. The concentration of urea in the culture medium is 10-50 g / L. The fermentation temperature is 32-40℃, the time is 12-72 h, and the pH of the culture medium is 6-8.

[0065] It should be noted that there are no particular restrictions on the reaction conditions of carbon dioxide and ammonia. For example, urea can be generated at a reaction temperature of 170-250℃ (preferably 200℃) and a reaction pressure of 10-20MPa (preferably 14.5MPa) in a high-pressure reactor, a high-pressure tubular reactor, a heat exchange reactor, or a fluidized bed reactor (preferably a high-pressure reactor).

[0066] According to a specific embodiment of the present invention, the method further includes:

[0067] The fermentation broth containing lactamide obtained from fermentation culture is separated and purified in order to obtain the final product lactamide.

[0068] It should be noted that there are no particular restrictions on the methods and conditions for separation and purification. For example, the separation and purification steps may include centrifugation, decolorization, filtration, evaporation, and crystallization.

[0069] It should be noted that the microorganisms contained in the microbial inoculant of this application are basically all alive. However, during actual production and storage, a small number of microorganisms may die due to various reasons. For example, the number of live bacteria in the microbial inoculant is not less than 80%, 85%, 90%, 95%, 98%, 99%, 99.5%, 99.9% of the total number of microorganisms.

[0070] According to a specific embodiment of the present invention, the microbial agent further includes culture medium, solvent (physiological saline, sterile water), protectant (lyophilization protectant, antioxidant, desiccant, etc.), stabilizer, preservative, etc., thereby further facilitating the storage or use of Lactobacillus reuteri, improving fermentation performance, and increasing lactamide yield.

[0071] This application does not impose strict requirements on the dosage form of microbial agents. For example, it can be a liquid (such as a suspension), powder, granules, etc., and can be flexibly selected according to actual needs.

[0072] In this application, the term "fermentation broth" refers to a liquid containing unconsumed culture medium components, microbial cells, and metabolic products during the fermentation process. The microbial cells in the fermentation broth may contain either live or dead microorganisms, for example, those that have undergone sterilization.

[0073] The fermentation broth can be concentrated using conventional concentration techniques in this field, such as distillation, to obtain a concentrate of the fermentation broth, the concentration factor of which can be adjusted according to actual needs.

[0074] By lysing the fermentation broth, all contents are released after cell rupture, including intracellular proteins, nucleic acids, lipids, and other organelles, as well as extracellular substances. The lysate is then subjected to conventional extraction techniques such as centrifugation, sedimentation, ultrafiltration, nanofiltration, or chromatography to obtain an extract.

[0075] By using conventional extraction techniques in this field, such as centrifugation, sedimentation, ultrafiltration, nanofiltration, or chromatography, the bacterial cells in the fermentation broth can be separated from the liquid. The liquid remaining after the bacterial cells are almost completely removed contains lactamide and is called the fermentation supernatant.

[0076] The present disclosure will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0077] Example 1: Preparation of Lactic Acid

[0078] (1) Preparation of recovered gaseous urea

[0079] The industrial exhaust gas is pretreated for dehydrogenation and desulfurization. The treated mixture containing carbon dioxide, carbon monoxide, oxygen, nitrogen and water vapor is compressed and cooled to 9 kPa and 40°C. The mixture is then introduced into a high-pressure reactor at a molar ratio of carbon dioxide to liquid ammonia of 1:3 to carry out a synthesis reaction at a reaction temperature of 200°C and a reaction pressure of 14.5 MPa to obtain recovered urea gas.

[0080] (2) Fermentation

[0081] A strain of Lactobacillus (Limosilactobacillus reuteri, deposited at Guangdong Provincial Microbial Culture Collection Center on May 29, 2024, accession number GDMCC NO: 64700) was inoculated into urea medium (pH 7.5) and fermented at 37℃ for 48 h to obtain a crude fermentation broth with a lactamide yield of 46 g / L.

[0082] Urea medium: 40 g / L urea, 20 g / L glucose, 10 g / L peptone, 8 g / L beef extract, 4 g / L yeast extract, 2 g / L dipotassium hydrogen phosphate, 5 g / L sodium acetate, 2 g / L diammonium hydrogen citrate, 0.2 g / L magnesium sulfate (MgSO4·7H2O), 0.04 g / L manganese sulfate (MnSO4·4H2O), 1 mL / L Tween-80, with the remainder being water;

[0083] (3) Separation and purification

[0084] Centrifugation: Centrifuge the crude fermentation broth at 8000 rpm and 4℃ for 10 min, and collect the supernatant;

[0085] Decolorization: Add 5 wt.% activated carbon to the supernatant, heat to 55°C, and stir for 30 min to decolorize;

[0086] Filtration: The sample is filtered through filter membranes and nanomembranes to retain small molecule filtrates with a molecular weight of <1000 Da;

[0087] Evaporation: The sample was subjected to vacuum distillation at a temperature of 60℃ and a pressure of 20kPa to remove moisture.

[0088] Crystallization: The mixture was cooled to 40℃, filtered, and pale yellow crystals were obtained. These crystals were then dried to obtain the final product, lactamide. The 1H NMR spectrum of the final product, lactamide, was analyzed, and the results are as follows: Figure 2 As shown, the obtained product is identified as lactamide.

[0089] Example 2 Preparation of lactamide

[0090] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the fermentation temperature in the (2) fermentation step is 32°C. Under these conditions, the yield of lactamide obtained by fermentation culture is 21 g / L.

[0091] Example 3: Preparation of Lactic Acid

[0092] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the fermentation temperature in the (2) fermentation step is 40°C. Under these conditions, the yield of lactamide obtained by fermentation culture is 37 g / L.

[0093] Example 4: Preparation of Lactic Acid

[0094] In this embodiment, the steps and conditions for (1) preparation of recovered gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the fermentation time in the (2) fermentation step is 12h. Under these conditions, the yield of lactamide obtained by fermentation culture is 14g / L.

[0095] Example 5: Preparation of Lactic Acid

[0096] In this embodiment, the steps and conditions for (1) preparation of recovered gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the fermentation time in the (2) fermentation step is 72h. Under these conditions, the yield of lactamide obtained by fermentation culture is 46g / L.

[0097] Example 6 Preparation of lactamide

[0098] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that in the (2) fermentation step, the concentration of urea in the culture medium is 10 g / L. Under these conditions, the yield of lactamide obtained by fermentation culture is 13 g / L.

[0099] Example 7 Preparation of lactamide

[0100] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that in the (2) fermentation step, the concentration of urea in the culture medium is 50 g / L. Under these conditions, the yield of lactamide obtained by fermentation culture is 24 g / L.

[0101] Example 8 Preparation of lactamide

[0102] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the pH of the urea culture medium in the (2) fermentation step is 6. Under these conditions, the yield of lactamide obtained by fermentation culture is 14 g / L.

[0103] Example 9: Preparation of Lactic Acid

[0104] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the pH of the urea culture medium in the (2) fermentation step is 8. Under these conditions, the yield of lactamide obtained by fermentation culture is 19 g / L.

[0105] Comparative Example 1: Preparation of Lactamide

[0106] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the fermentation temperature in the (2) fermentation step is 25°C. Under these conditions, the yield of lactamide obtained by fermentation culture is 2 g / L.

[0107] Comparative Example 2: Preparation of Lactamide

[0108] In this embodiment, the steps and conditions for (1) preparation of recovered gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the fermentation temperature in the (2) fermentation step is 45°C. Under these conditions, the yield of lactamide obtained by fermentation culture is 5 g / L.

[0109] Preparation of lactamide (Comparative Example 3)

[0110] In this embodiment, the steps and conditions for (1) preparation of recovered gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the fermentation time in the (2) fermentation step is 8 hours. Under these conditions, the yield of lactamide obtained by fermentation culture is 8 g / L.

[0111] Comparative Example 4: Preparation of Lactamide

[0112] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that in the (2) fermentation step, the concentration of urea in the culture medium is 5 g / L. Under these conditions, the yield of lactamide obtained by fermentation culture is 3 g / L.

[0113] Preparation of lactamide (Comparative Example 5)

[0114] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that in the (2) fermentation step, the concentration of urea in the culture medium is 60 g / L. Under these conditions, the yield of lactamide obtained by fermentation culture is 7 g / L.

[0115] Preparation of lactamide (Comparative Example 6)

[0116] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the pH of the urea culture medium in the (2) fermentation step is 5. Under these conditions, the yield of lactamide obtained by fermentation culture is 2 g / L.

[0117] Preparation of lactamide in Comparative Example 7

[0118] In this embodiment, the steps and conditions for (1) preparation of gaseous urea, (2) fermentation, and (3) separation and purification are the same as in Example 1. The only difference is that the pH of the urea culture medium in the (2) fermentation step is 10. Under these conditions, the yield of lactamide obtained by fermentation culture is 9 g / L.

[0119] The results of Examples 1-9 and Comparative Example 7 above indicate that the method for producing lactamide using carbon dioxide provided by the present invention has a certain influence on the lactamide yield, including fermentation temperature, time, urea concentration in the culture medium, and pH of the culture medium. In particular, a relatively high lactamide yield can be obtained when the fermentation temperature is 32-40℃, the time is 12-72h, the urea concentration in the culture medium is 10-50g / L, and the pH of the culture medium is 6-8. Lactic acid can still be produced when the conditions during the fermentation process are not within this range, but the lactamide yield will be affected.

[0120] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0121] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. The use of microorganisms or microbial agents containing said microorganisms in the preparation of lactamide, characterized in that, The microorganism in question is *Limosilactobacillus reuteri*, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on May 29, 2024, with accession number GDMCC NO: 64700.

2. A method for preparing lactamide, characterized in that, include: Urea is mixed with a culture medium containing microorganisms and fermented to prepare lactamide. The microorganism in question is *Limosilactobacillus reuteri*, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on May 29, 2024, with accession number GDMCC NO: 64700. The culture medium contains glucose.

3. The method according to claim 2, characterized in that, The urea is produced by reacting carbon dioxide and ammonia.

4. The method according to claim 2, characterized in that, The fermentation culture is carried out at a temperature of 32-40℃ for 12-72 hours.

5. The method according to claim 2, characterized in that, The fermentation culture is carried out at a temperature of 36-38℃ for 45-50 hours.

6. The method according to claim 2, characterized in that, During fermentation, the concentration of urea in the culture medium is 10-50 g / L.

7. The method according to claim 2, characterized in that, During fermentation, the concentration of urea in the culture medium is 35-45 g / L.

8. The method according to claim 2, characterized in that, The pH of the culture medium is 6-8, preferably 7-8.

9. The method according to claim 2, characterized in that, The concentration of glucose in the culture medium is 10-30 g / L.

10. The method according to claim 2, characterized in that, The method further includes: The fermentation broth containing lactamide obtained from the fermentation culture is separated and purified in order to obtain the final product lactamide; Optionally, the separation and purification steps include: centrifugation, decolorization, filtration, evaporation, and crystallization.

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