A method for preparing hydrogel using fermented bacteria as raw materials

Abstract

The present invention belongs to the field of fermentation engineering and chemical engineering, and specifically relates to the preparation of hydrogel by resource utilization of fermented bacteria after the fermentation production is completed. The present invention moderately lyses the fermented bacteria under the action of a lysing enzyme or a chemical lysing agent to release bacterial macromolecules. The lysed bacterial liquid contains components such as protein, nucleic acid, chitosan and peptidoglycan. The macromolecules in the bacterial lysate are cross-linked with chitosan macromolecules to prepare hydrogel, thereby realizing the product application of discarded fermented bacteria. At the same time, the hydrogel product prepared by the present invention can be used in the fields of seed coating, agricultural water absorbent, etc., and has the characteristics of being beneficial to improving seed germination rate.

Description

Technical field:

[0001] The invention belongs to the field of fermentation engineering and chemical engineering, and specifically relates to the preparation of hydrogel by resource utilization of fermented bacteria after the fermentation production is completed. Background technology:

[0002] Taking the fermentation of glutamate and refined monosodium glutamate by Corynebacterium glutamicum as an example, 200 kg of dry bacteria can be extracted from the fermentation liquid for every ton of monosodium glutamate produced, so the annual bacterial protein produced in China is about 22×10 4 Tons (Zhou Dawei, Xiao Dongguang, Guo Xuewu, Lv Hongyan. Food Research and Development, 2012). In addition, China produces more than 10,000 tons of L-tryptophan by Escherichia coli each year, and the production of 1 ton of L-tryptophan is accompanied by the production of 1.3-1.5 tons of waste bacterial cells (WBC) (Qingyang Xu, Fang Bai, Ning Chen, and Gang Bai, Bioengineered, 2019). When Rhizopus oryzae is used to ferment lactic acid, 84.5 kg of Rhizopus oryzae fungi are produced for every ton of lactic acid obtained (Yang Lei, Li Xin, Yu Shiyuan. Forest Products Chemistry and Industry, 2015).

[0003] Existing fermentation cell processing processes include using waste cell proteins to prepare cell protein powder with comprehensive nutritional components to replace yeast paste and reduce the cost of fermentation culture medium (Chinese patent application CN106086093A; Chinese patent application CN 110092528 A); preparing peptide products and feed products with higher purity to avoid waste of cell raw materials (Chinese patent application CN107011409A; Chinese patent application CN107418897A); using amino acid fermentation waste cells to prepare liquid organic fertilizer (Chinese patent application CN106116773A), and using vitamin C fermentation waste to produce cell protein and polypeptide organic fertilizer (Chinese patent application CN111995467A).

[0004] Taking Gram-negative bacteria as an example, the cell wall consists of a peptidoglycan layer and an exine layer. The exine layer is mainly composed of lipopolysaccharide and lipoprotein. The phospholipid bilayer is the basic scaffold of the cell membrane. The main components of the cell membrane are proteins and lipids, containing a small amount of carbohydrates. Hydrogel is a polymer material formed by a hydrophilic polymer cross-linking network and then swelling with water, usually prepared from natural or synthetic polymers. Its mechanical properties can be tested by a universal material testing machine, its structure can be characterized by an infrared spectrometer, its thermal properties can be analyzed by a differential scanning calorimeter, its surface porous structure and longitudinal cross-section pore orientation can be observed by a scanning electron microscope, and the hydrogel swelling rate can be calculated by a formula.

[0005] Hydrogels are usually composed of a three-dimensional hydrophilic polymer network formed by covalent bonds, hydrogen bonds and / or physical entanglement. They have good water solubility and biocompatibility, and therefore have applications in drug delivery, tissue engineering and biosorbents. Some well-known examples are polyethylene glycol (PEG), polyacrylamide (PAM) and polyvinyl alcohol (PVA), all of which are hydrophilic. However, their inherent toxicity hinders healthy use. Therefore, biopolymers such as chitosan, alginate and cellulose have been considered as alternatives to create more biocompatible, biodegradable and low-toxic consumer-friendly gels. The hydrogel products prepared by the present invention can be applied to seed coatings, agricultural water absorbents and other directions.

[0006] The existing treatment methods of fermented bacteria usually have problems such as high treatment cost and great environmental pressure, and most fermented bacteria have not yet achieved "turning waste into treasure". The present invention makes full use of macromolecules such as proteins, polysaccharides and nucleic acids released after bacterial lysis, and cross-links them with degradable polymers such as chitosan to prepare new hydrogel materials that can be used in seed coating, green plant insulation, and fertilizer slow release. Summary of the invention:

[0007] The purpose of the present invention is to release bacterial macromolecules from fermented bacteria under the action of lysing enzymes or chemical lysing agents. The lysed bacterial solution contains components such as proteins, nucleic acids, chitosan and peptidoglycan, as well as various monovalent and divalent ions and cell fragments. The proportion of small molecule peptides and monosaccharides and oligosaccharides in the lysate is less than 10%. Then, the macromolecules in the bacterial lysate are cross-linked with chitosan macromolecules to prepare hydrogel, thereby realizing the product application of discarded fermented bacteria.

[0008] One of the technical solutions provided by the present invention is a method for preparing a hydrogel material using fermentation waste bacteria, comprising the following steps:

[0009] (1) Collecting the microorganisms before or after extracting the target product from the microbial fermentation broth;

[0010] Further, a flocculant is added to the fermentation liquid to collect the bacterial cells;

[0011] Furthermore, the flocculant is chitosan, and the addition amount is 0.01% to 1% (w / v) of the fermentation broth;

[0012] Further, the flocculation conditions are: stirring speed 100-300 r / min, flocculation temperature 45-85°C, and adjusting the pH to 6-10 after stirring for 5-20 minutes;

[0013] Furthermore, chitosan is added in an amount of 0.06% to 0.3%, and calcium hydroxide is used to adjust the pH to 7 to 8.5;

[0014] Further, the bacteria are collected by plate and frame filtration, membrane filtration or centrifugation;

[0015] Furthermore, the fermentation liquid is a lactic acid fermentation liquid using Escherichia coli as the fermentation bacteria;

[0016] (2) treating the collected bacteria with a lytic enzyme and / or a chemical lytic agent to prepare a bacterial lysate;

[0017] Furthermore, the cell disruption rate in the bacterial lysate is 84% ​​to 99.5%, and the protein content in the lysate ranges from 62 to 239 mg / g, the nucleic acid content ranges from 6 to 75 mg / g, and the peptidoglycan content ranges from 1.2 to 14.95 mg / g;

[0018] Furthermore, the lytic enzyme is at least one of lysozyme, snail enzyme, cellulase or wall-lytic enzyme;

[0019] Furthermore, the chemical lysing agent includes but is not limited to NaOH, KOH, SDS, Triton X-100, etc.;

[0020] Further, the pyrolysis conditions are: 40°C to 100°C, pyrolysis for 10 to 30 min;

[0021] Furthermore, the lysis is carried out at 50°C to 100°C and pH 7 to 14 for 15 to 30 min;

[0022] Further, the collected bacteria were resuspended and then added with a final concentration of 0.5-3 M sodium hydroxide and 0.25-1.0% (w / v) SDS as a lysis agent;

[0023] Furthermore, the collected bacteria were resuspended and then added with sodium hydroxide at a final concentration of 0.5 to 1.5 M and SDS at 0.25 to 1% (w / v) as a lysis agent;

[0024] (3) allowing the bacterial lysate to stand to prepare a hydrogel;

[0025] Furthermore, the bacterial lysate forms a hydrogel after being left to stand for 4 to 12 hours.

[0026] The present invention also provides a hydrogel material prepared by the above method.

[0027] The present invention also provides applications of the hydrogel material, particularly in the fields of seed coating, green plant insulation, and fertilizer slow release.

[0028] Beneficial effects achieved by the present invention:

[0029] The present invention can efficiently collect and moderately lyse the cells in the fermentation liquid and use them to prepare hydrogels, thereby achieving the simultaneous production of fermentation products and hydrogels derived from fermentation cells, and completely solving the problem of recycling fermentation cell waste in the existing industrial production system. This can also significantly improve the economic efficiency and environmental benefits of fermentation production and significantly reduce the comprehensive cost of fermentation product production.

[0030] The present invention can also be applied to the recovery and utilization of bacteria in the production process of other organic acids such as lactic acid, citric acid, malic acid, succinic acid, etc., or amino acids such as lysine, glutamic acid, threonine, alanine, etc.

[0031] When collecting the cells after lactic acid fermentation, the present invention uses chitosan as a biological flocculant and maintains a certain temperature and pH, so that the flocculant is collected together with the cells without affecting the subsequent separation and purification of lactic acid, and the collected cells are simply lysed to produce a hydrogel with good rheological properties and swelling properties. The key point of the process is the control of the degree of fermentation cell lysis, that is, the degree of cell fragmentation in the system, and the control of the concentrations of protein, nucleic acid, and peptidoglycan.

[0032] The hydrogel product prepared by the invention can be applied to seed coating, agricultural water absorbent and the like.

[0033] The present invention makes full use of macromolecules such as proteins, polysaccharides and nucleic acids released after bacterial lysis, and cross-links them with degradable polymers such as chitosan to prepare new hydrogel or blended membrane materials suitable for seed coating, green plant insulation, and fertilizer slow release. Compared with the hydrogel prepared by chitosan alone, the hydrogel prepared by the present invention has protein that increases the toughness of the hydrogel system, and can release nutrients such as protein for seed uptake during the process of seed coating or agricultural water absorbent, which is beneficial to improving the seed germination rate and other characteristics. Specific implementation method:

[0034] In order to make the purpose, technical solution and advantages of this patent more clear, this patent is further described in detail in combination with specific embodiments. It should be understood that the specific embodiments described here are only used to explain this patent and are not used to limit the present invention.

[0035] The present invention takes the fermentation broth of lactic acid produced by the calcium salt method as an example. After the lactic acid fermentation is completed, the fermentation broth is heated to 45°C-85°C, a bioflocculant chitosan is added and stirred to maintain the reaction for 5-20 minutes, and then solid-liquid separation is performed by filtration. The collected solid part is the bacterial body, and the collected liquid part is the free lactic acid liquid containing lactic acid monomer. The obtained bacterial body can be used for the subsequent preparation of hydrogel. The obtained free lactic acid liquid is filtered, concentrated, etc., to be a crude lactic acid product, which can be used for subsequent refining such as nanofiltration, decolorization, and cross-linking to obtain high-purity lactic acid monomer.

[0036] The main experimental methods used in the present invention are as follows:

[0037] (1) Preparation of fermentation liquid - collection of bacteria (flocculation). The preparation of lactic acid fermentation liquid by calcium salt method was carried out according to the invention patent (Wang Zhengxiang et al., ZL201580000781.7), and the fermentation strain was CGMCC 11059 or CGMCC11060, wherein the strain CGMCC 11059 was used for the fermentation production of D-lactic acid, and the strain CGMCC11060 was used for the fermentation production of L-lactic acid (Wang Zhengxiang et al., ZL201580000781.7). At the initial stage of fermentation, glucose is added to the fermentation basic medium to a final concentration of 10-50 g / L, and the culture is carried out at 30-37° C., pH 5.5-7.5, ventilation 0.1-2.0 vvm, and stirring at 100-1000 r / min; the culture time is 5-15 hours, and the bacterial volume reaches 10-50 OD; the ventilation is closed, the stirring speed is reduced to 0-300 r / min, the fermentation temperature is increased to 37-50° C., a glucose solution with a final concentration of 16%-25% is added, the flow acceleration is controlled at 3g / (L h)-25g / (L h), 5%-35% calcium hydroxide is added synchronously, and the fermentation pH is controlled between 5.0 and 8.0. Flocculation is to add 0.1-10g / L of bioflocculant chitosan to the fermentation liquid, with a stirring time of 5-20min, a stirring speed of 100-300r / min, a flocculation temperature of 45-85°C, adjust the pH of the fermentation liquid to 7.0-8.5 with calcium hydroxide, and collect the bacteria by filtration.

[0038] (2) Bacterial lysis: Use NaOH solution and SDS solution to break the cell wall of E. coli, add NaOH to a final concentration of 0.5-3M, and SDS to a final concentration of 0.25-1.5% (w / v), at a temperature of 40°C-100°C, pH 7-14, and for 10-30 minutes.

[0039] (3) Preparation of hydrogel: The above-mentioned bacterial lysate was allowed to stand at room temperature for 4 to 12 hours to obtain a hydrogel.

[0040] The present invention is further explained below by means of specific examples.

[0041] Example 1 A D-lactic acid fermentation method

[0042] The frozen glycerol tube of D-lactic acid producing strain CGMCC NO.11059 was inoculated into 50 mL of LB liquid medium and cultured at 37°C and 200 r / min for 12 hours as the first-level seed liquid. The first-level seed liquid was inoculated into 5 L of M9 liquid medium with glucose as the carbon source, with an initial sugar concentration of 0.5%, and cultured at 37°C and 200 r / min for 10 hours as the second-level seed liquid. The second-level seed liquid was inoculated into a fermenter filled with M9 liquid medium at an initial OD value of 0.3. 5 minutes after inoculation, the fermenter was inoculated with 100 mL of LB liquid medium. 3 The initial volume of the fermenter is 2.5m 3 , the initial invert syrup addition amount was 3%, and the fermentation production of lactic acid monomer began. The fermentation starting temperature was controlled at 37°C, and the pH was maintained at 6.5 with ammonia water. During the bacterial growth process, the ventilation volume was adjusted to 1.5vvm, and the stirring speed was 600r / min. When the bacterial concentration reached OD 600 After 30 minutes, the ventilation was turned off, the fermentation temperature was controlled at 40°C, the stirring speed was adjusted to 200r / min, 25% calcium hydroxide suspension was added to maintain the pH at 7.0, and a total of 6.0kg of glucose was added. The fermentation ended when the residual sugar concentration was lower than 0.5g / L.

[0043] M9 culture medium composition: NaCl 0.5 g / L, NH4Cl 1 g / L, KH2PO4 3 g / L, Na2HPO4·12H2O 15.1 g / L, and the rest is water.

[0044] The obtained lactic acid fermentation liquid was used as a raw material, heated to 60°C in a reactor and maintained at this temperature, 2 g / L of chitosan solution was added under stirring at 100 r / min, and after all the chitosan solution was added, the reaction was maintained for 15 minutes, and 20% calcium hydroxide was added to adjust the pH of the fermentation liquid to 7.5; after the reaction was completed, the solid-liquid separation of the reaction liquid was carried out using a plate and frame filter device with a filtration pore size of 6 μm, and the collected solid part was the bacterial body.

[0045] Example 2-1: Lysis effect at different concentrations of lysing agents

[0046] The bacterial cells obtained in Example 1 and water were resuspended three times at a ratio of 1:4 (w / v), and then 0.25-1.5M NaOH and 0.5% SDS solution, and 0.25-1% SDS solution and 1M NaOH were added at 50°C for 20 minutes to break the cell wall. The components of the lysate in the lysate after lysis are shown in Tables 1 and 2. The bacterial lysate was placed in a centrifuge tube and allowed to stand at room temperature for 6 hours, and the hydrogel formation was observed by inverting the centrifuge tube.

[0047] Table 1. Pyrolysis data corresponding to different NaOH concentrations (0.5% SDS solution)

[0048]

[0049]

[0050] Table 2. Pyrolysis data corresponding to different SDS concentrations (1M NaOH)

[0051]

[0052] Example 2-2: Cracking effect at different temperatures

[0053] The bacterial cells obtained in Example 1 and water were resuspended three times at a ratio of 1:4 (w / v), and then a final concentration of 1M NaOH and 0.5% SDS solution were added for cell wall breaking treatment at different temperatures (20-90°C) for 20 minutes. The components of the lysate in the lysate after lysis are shown in the following table. The bacterial lysate was placed in a centrifuge tube and allowed to stand at room temperature for 6 hours, and the hydrogel formation was observed by inverting the centrifuge tube.

[0054] Table 3 Cracking data corresponding to different cracking temperatures

[0055]

[0056] Example 2-3: Lysis effect at different lysis times

[0057] The bacterial cells obtained in Example 1 and water were resuspended three times at a ratio of 1:4 (w / v), and then a final concentration of 1M NaOH and 0.5% SDS solution were added for cell wall disruption at 70°C for different times (5-35 min). The components of the lysate in the lysate after lysis are shown in the following table. The bacterial lysate was placed in a centrifuge tube and allowed to stand at room temperature for 6 hours, and the hydrogel formation was observed by inverting the centrifuge tube.

[0058] Table 4 Corresponding data of different lysis time

[0059]

[0060] The protein content was determined by the Coomassie brilliant blue method, the nucleic acid content was determined by the ultraviolet absorption method, and the peptidoglycan content was determined by the glucosamine standard curve method (Zeng Min, Xie Weitian, Pan Limei, Xu Chunhou. Feed Industry. 2010).

[0061] Cell disruption rate = [1-(OD 600 / OD before lysis 600 )]×100%.

[0062] Among them, 1OD = 0.462 × 10 9cells / mL. (Kangming Tian, ​​Dandan Niu, Zhengxiang Wang. Biotechnology and Bioengineering. 2015).

[0063] Through the above experiments, it was determined that the main factors affecting gelation are cell fragmentation rate, protein concentration, nucleic acid concentration and peptidoglycan concentration in the system. On the basis of the above experiments, the inventors conducted a large number of experimental verifications and finally determined that the optimal conditions for bacterial lysate to form hydrogels are: cell fragmentation rate is 84% ​​to 99.5%, while the protein content in the lysate is in the range of 62 to 239 mg / g, the nucleic acid content is 6 to 75 mg / g, and the peptidoglycan content is 1.2 to 14.95 mg / g.

[0064] The suitable lysis conditions for forming the hydrogel are: NaOH final concentration 0.5-3M, SDS concentration 0.25-1%, temperature 40-100°C, and lysis time between 10min and 30min.

[0065] Example 3: Hydrogels formed under different lysis conditions

[0066] The bacterial cells obtained in Example 1 and water were resuspended three times at a ratio of 1:4 (w / v), and then NaOH and SDS solutions of a certain final concentration were added for cell wall breaking at a certain temperature for a certain time. The components of the lysate in the lysate after lysis are shown in the following table. The bacterial lysate was placed in a centrifuge tube and allowed to stand at room temperature for 6 hours, and the hydrogel formation was observed by inverting the centrifuge tube.

[0067] Table 5 Corresponding data of different cracking conditions

[0068]

[0069] Example 4: Rheological characterization of hydrogels

[0070] The structural formation of macromolecules in the hydrogel system can be explained by determining the viscoelasticity through dynamic measurement. Rheological measurements were performed on the viscoelastic properties of the hydrogel. The rheological test of bacterial lysate hydrogel was performed using a rotational rheometer. The test temperature was 25°C, the amplitude scanning test condition was ω 10 rad / s, the amplitude range was 0.01-100%, and the frequency scanning test condition was 0.1-100 rad / s, the amplitude was 1%.

[0071] The elasticity is represented by the storage modulus G', while the viscosity is explained by the loss modulus G". In the hydrogels formed in Examples 2-1, 2-2 and 2-3, G' is always higher than G", and the storage modulus G' value is about 3 to 5 times the loss modulus G", G'≈10 4 , G"≈10 3, indicating that all hydrogels have stable structures and good viscoelasticity.

[0072] As the strain increases, the storage modulus and loss modulus intersect and the network structure is destroyed.

[0073]

[0074]

[0075] Example 5: Performance parameters of the hydrogel product of the present invention

[0076] The corresponding swelling ratio and mechanical property data of some hydrogels obtained in Examples 2 and 3 of the present invention are as follows:

[0077]

[0078] References for determination of relevant parameters (Xu Mengyuan, Liu Rangtong, Li Liang, Liu Shuping, Li Shujing. Printing and Dyeing, 2022)

[0079] Preparation of chitosan hydrogel: Weigh 2.5 g of 1% chitosan solution in a 25 mL container, add deionized water to 10 mL and stir with a magnetic stirrer at 90 ° C to dissolve chitosan into a transparent clear solution, and let stand for 6 hours. In Example 1 of the present invention, 0.2% chitosan solution was added to the fermentation broth, and the chitosan content accounted for 1% of the bacterial content after flocculation, and the chitosan content accounted for 0.25% of the bacterial lysate after bacterial lysis. Therefore, the chitosan concentration of the chitosan hydrogel in this embodiment is 0.25%.

[0080] Preparation of bovine serum albumin hydrogel: 1.55 g of bovine serum albumin was weighed into a 25 mL container, 8.45 g of deionized water (final concentration of bovine serum albumin: 155 mg / g) was added, and the solution was stirred at 90°C with a magnetic stirrer to dissolve the bovine serum albumin into a transparent clear solution, and then allowed to stand for 6 h.

[0081] Preparation of chitosan + bovine serum albumin hydrogel: weigh 2.5 g of 1% chitosan solution and 1.55 g of bovine serum albumin in a 25 mL container, add deionized water to make up to 10 g and stir with a magnetic stirrer at 90 °C to dissolve into a transparent clear solution, and let it stand for 6 h.

[0082] It can be seen from the above experiments that, under the condition of equivalent chitosan or protein concentration, the hydrogel prepared by the bacterial lysate of the present invention has better swelling rate, tensile strength and elongation at break, and has more superior performance. The hydrogel can quickly absorb water and swell without dissolving in water. When combined with water, it can show high swelling and has good water retention performance. Its high water retention performance can provide a good environment for seeds, prevent water loss, and extend the shelf life; good tensile strength and elongation at break can make the hydrogel not easy to break during the seed coating process, and better contact with the seeds to form a coating.

[0083] Example 6: Application of the hydrogel of the present invention as seed coating

[0084] The hydrogel prepared by the lysis conditions of the present invention, 1.5M NaOH, 0.5% SDS, 40°C, 20min (Example 3); 1M NaOH, 0.5% SDS, 70°C, 25min (Examples 2-3); 1.5M NaOH, 0.75% SDS, 90°C, 15min; 2.5M NaOH (Example 3), 0.75% SDS, 100°C, 25min (Example 3), was applied to seed coating, as follows:

[0085] Immerse soybean seeds evenly in the hydrogel, stir thoroughly, let stand for 30 minutes, then take them out, spread them out to dry, and wait until a thin film forms on the surface of the seeds, which takes about 1 to 2 hours.

[0086] At the same time, the same seeds were wrapped with hydrogels prepared with chitosan, hydrogels prepared with bovine serum albumin, and hydrogels prepared with chitosan + bovine serum albumin, and seeds without any treatment were used as controls. All seeds were germinated (soaked in clean water for 14 hours, removed to control excess water, covered with two layers of wet filter paper, and watered every day to keep the filter paper slightly moist for three or four days) and sown, and the seed germination rate was calculated. The data obtained are as follows:

[0087]

[0088] Preparation of chitosan hydrogels 1, 2, and 3: Weigh 2.5 g of 1% chitosan solution into a 25 mL container, add deionized water to 10 mL, and stir with a magnetic stirrer at 70°C, 90°C, and 100°C to dissolve the chitosan into a transparent clear solution, and let it stand for 6 h.

[0089] Preparation of bovine serum albumin hydrogels 1, 2, and 3: Weigh 1.10 g, 1.55 g, and 2.30 g of bovine serum albumin into a 25 mL container, add deionized water to make up to 10 g (final concentration of bovine serum albumin: 110 mg / g, 155 mg / g, and 230 mg / g), and stir with a magnetic stirrer at 70°C, 90°C, and 100°C, respectively, to dissolve the bovine serum albumin into a transparent, clear solution, and let it stand for 6 h.

[0090] Preparation of chitosan + bovine serum albumin hydrogels 1, 2, and 3: Weigh 2.5 g of 1% chitosan solution and 1.10 g, 1.55 g, and 2.30 g in 25 mL containers, respectively, add deionized water to make up to 10 g, and stir with a magnetic stirrer at 70 °C, 90 °C, and 100 °C to dissolve the chitosan and protein into a transparent clear solution, and let it stand for 6 h.

[0091] It can be seen from the above experiments that under the same chitosan or protein concentration, the hydrogel prepared from bacterial lysate as seed coating is more conducive to seed germination.

[0092] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing a hydrogel material using fermentation waste cells, characterized in that: The following steps are involved: (1) Before extracting the target product from the microbial fermentation broth, chitosan is added to the fermentation broth as a flocculant to collect the microorganisms; The microbial fermentation liquid is a lactic acid fermentation liquid with Escherichia coli as the fermentation strain; (2) After the collected bacterial cells are resuspended, sodium hydroxide with a final concentration of 1 to 3 M and 0.5 to 1.0% SDS are added as a lysing agent, and the cells are lysed at 50° C. to 100° C. for 15 to 30 min to prepare a bacterial lysate; The cell disruption rate in the bacterial lysate is 84% ​​to 99.5%, and the protein content in the lysate is 62 to 239 mg / g, the nucleic acid content is 6 to 75 mg / g, and the peptidoglycan content is 1.2 to 14.95 mg / g; (3) The bacterial lysate is allowed to stand to prepare the hydrogel.

2. The method for preparing a hydrogel material using fermentation waste cells according to claim 1, characterized in that: The flocculation conditions are as follows: stirring speed 100-300 r / min, flocculation temperature 45-85°C, and adjusting the pH to 6-10 after stirring for 5-20 minutes.

3. The method for preparing a hydrogel material using fermentation waste cells according to claim 1, characterized in that: The flocculant is chitosan, and the added amount is 0.01% to 1% of the fermentation liquid.

4. The method for preparing a hydrogel material using fermentation waste cells according to claim 1, characterized in that: The amount of chitosan added is 0.06% to 0.3%, and after reacting for 5 to 20 minutes, calcium hydroxide is used to adjust the pH to 7 to 8.

5.

5. The method for preparing a hydrogel material using fermentation waste cells according to claim 1, characterized in that: The bacterial lysate forms a hydrogel after being left to stand for 4 to 12 hours.

6. A hydrogel material prepared by the method according to any one of claims 1 to 5.

7. The use of the hydrogel material according to claim 6, characterized in that: Applied in the fields of seed coating, green plant insulation, or fertilizer slow-release technology.

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