A method for in-situ regulation of crystallinity of bacterial cellulose and products and applications thereof

Abstract

The application discloses a method for in-situ regulation of crystallinity of bacterial cellulose, and products and applications thereof. In the process of microbial synthesis of bacterial cellulose gel, a small amount of non-carbon source crystallization accumulation regulator, such as sodium dodecyl benzene sulfonate, dodecyl phosphate, sodium methyl cocoyl taurate, sodium palmitate and the like, is added in-situ to prepare bacterial cellulose with different crystallinity. The application solves the problems of high crystallinity of bacterial cellulose and single crystallinity of bacterial cellulose, realizes in-situ regulation of crystallinity during synthesis, and significantly increases the water content and reduces the crystallinity of bacterial cellulose without changing the crystal form and chemical structure of bacterial cellulose. The application has low cost, simple process, and is compatible with the existing bacterial cellulose synthesis and preparation process, and innovatively expands the application of bacterial cellulose in more fields such as low-crystallinity processing and high-water-retention-demand.

Description

Technical Field

[0001] This invention belongs to the field of bacterial cellulose preparation, and relates to a method for reducing the crystallinity of bacterial cellulose in situ during synthesis. Specifically, it relates to a method for in situ regulating the crystallinity of bacterial cellulose, its products, and applications. Background Technology

[0002] Bacterial cellulose (BC) is a polysaccharide polymer synthesized by microorganisms. It is characterized by high cellulose purity, free of hemicellulose, lignin, and pectin. The molecular structure of bacterial cellulose is primarily composed of β-1,4-glucose units, forming a highly ordered crystalline structure. This high crystallinity (≥80%), excellent mechanical strength, and biocompatibility make it widely used in dietary fiber, medical dressings, and other fields. X-ray diffraction (XRD) is the primary characterization method for measuring the crystallinity of bacterial cellulose. However, the high crystallinity often makes BC difficult to process, limiting its application in many areas. Existing modification methods include chemical treatment (such as acid hydrolysis and derivatization) and physical blending, but these methods suffer from complex processes and high costs.

[0003] Currently, there are a few studies and patents reporting on altering the crystallization and stacking of bacterial cellulose during synthesis. For example, in 1982, R. Malcolm Brown, Jr.'s team in the United States added fluorescent whitening agent M2R or Tinopal LPW to the BC synthesis system. When the dosage reached 8 μmol / L, bacterial cellulose was synthesized in a non-fibrous lamellar form, and the crystallinity changed, but no specific tests or calculations of crystallinity were performed. In 2013, Hu Yang et al., in their invention patent "A Method for Reducing the Crystallinity of Bacterial Cellulose during Fermentation," used a mixture of fluorescent whitening agent M2R and Evans blue. When the dosage was 0.01%-1% of the culture medium volume, the crystallinity of BC could be reduced to 71-55%. All these studies used Hestrin-Schramm standard medium to synthesize bacterial cellulose.

[0004] Several invention patents pioneered by our team, including "A method for producing bacterial cellulose gel using coconut food processing wastewater" (Patent No. ZL 2022 1 0484679.0), "A method for producing bacterial cellulose gel directly using livestock and poultry slaughter wastewater" (Application No. CN202210972066.1), and "A method for producing bacterial cellulose gel directly using tilapia processing wastewater" (Application No. CN202310599714.8), provide more references for culture media for the biosynthesis of BC in this invention. Summary of the Invention

[0005] To address the performance limitations and processing difficulties caused by the high crystallinity of bacterial cellulose, this invention proposes in-situ addition of a non-carbon source crystallization packing regulator to the synthesis culture medium. The regulator's molecular structure interferes with the ordered arrangement of cellulose molecular chains, thereby controlling crystallinity in situ. This method requires no additional equipment, is simple, and requires only a small amount of the non-carbon source crystallization packing regulator, resulting in low cost. It also does not alter the crystal form or chemical structure of the synthesized BC. This invention provides a simple and effective method for altering the crystallinity of bacterial cellulose by adding a non-carbon source crystallization packing regulator.

[0006] The technical solution implementation steps of this invention are as follows: A production medium for producing bacterial cellulose gel, wherein each liter of medium contains 0.05-0.5 g of a non-carbon source crystallization stacking regulator.

[0007] Furthermore, each liter of culture medium contains 0.05-0.3g of non-carbon source crystallization accumulation regulator.

[0008] Furthermore, the culture medium is a bacterial cellulose production medium, such as naturally fermented coconut water, or Hestrin-Schramm standard medium, or other fruit juices or food processing wastewater containing biomass, such as coconut food processing wastewater, tilapia processing wastewater, livestock and poultry slaughtering wastewater, and soy product processing wastewater. Besides the above-mentioned culture media, other culture media used for cultivating bacterial cellulose can also be selected in production; this invention does not impose any particular limitation.

[0009] Furthermore, the non-carbon source crystallization stacking regulator is at least one of the following: sodium dodecylbenzene sulfonate (SDBS), mono-n-dodecyl phosphate (MDP), sodium methyl cocoyl taurate (SMCT), and / or sodium palmitate (PA), which are amphiphilic molecules with long carbon chain nonpolar ends and highly sterically hindered polar ends.

[0010] A method for producing bacterial cellulose gel includes the following steps: (1) Take the production culture medium, add an appropriate amount of nitrogen source and / or carbon source if necessary, and adjust the pH value; (2) After inoculating with a bacterial strain that produces bacterial cellulose, bacterial cellulose gel is obtained by culturing.

[0011] Furthermore, in step (1), the production culture medium may be supplemented with an appropriate amount of nitrogen source and / or carbon source if necessary to ensure the normal growth of the bacterial cellulose-producing strain and the biosynthesis of BC required; the production culture medium is filtered to obtain a clear liquid, which is then sterilized at high temperature and used to culture bacterial cellulose.

[0012] Furthermore, filtration is performed using a filter screen with a mesh size of 100-200. The purpose of filtration is to remove solid particles and foam from the culture medium, preventing foam from reducing the sterilization effect.

[0013] Furthermore, sterilization is performed using hydrothermal high-temperature sterilization at 121°C for 10-25 minutes, with the optimal sterilization time being 15 minutes. If a large amount of foam is found in the culture medium, the sterilization time can be appropriately extended. Excessive heating time may cause loss of nutrients in the culture medium.

[0014] Furthermore, in step (1), the pH value is adjusted to 3.8-4.8, preferably 4.0-4.5.

[0015] Furthermore, in step (2), the bacterial strain producing bacterial cellulose can be acetic acid bacteria, xylitol bacteria, or other strains capable of biosynthesizing bacterial cellulose, preferably... Komagataeibacter xylinus HN002.

[0016] Furthermore, in step (2), after inoculating the bacterial cellulose-producing strain, static culture is carried out. Static culture is conducive to the formation of membrane-like bacterial cellulose gel. The culture conditions are: culture at 28-35℃ for 5-10 days.

[0017] A method for in situ regulating the crystallinity of bacterial cellulose includes the following steps: Bacterial cellulose was produced by fermentation using the above-mentioned production culture medium.

[0018] The above-described production culture medium, production method, or in-situ regulation method for bacterial cellulose crystallinity is applied to reducing the crystallinity of bacterial cellulose gel and / or increasing the water content of bacterial cellulose without affecting the crystal form and / or chemical structure of bacterial cellulose.

[0019] A bacterial cellulose, which is obtained by the above-mentioned production method or by the method of in-situ regulation of bacterial cellulose crystallinity.

[0020] The bacterial cellulose gel described herein is used in the preparation of hydrogel materials, highly absorbent materials, and / or functional membrane materials. For example, it can be used as a mask substrate, BC suspension, or emulsion particles, taking advantage of its low crystallinity and high water-holding capacity.

[0021] Beneficial effects: This invention introduces a non-carbon source crystallization packing regulator into the in-situ synthesis of cellulose (BC). By interfering with the ordered packing of cellulose molecular chains, it significantly reduces crystallinity (from 86.51% to 70.57%) and improves material properties. The addition of this specially structured non-carbon source crystallization packing regulator not only alters the packing structure of BC in situ but also enhances properties such as water retention while preserving the crystalline form. This avoids additional modification steps, achieving in-situ regulation and making it suitable for downstream processing and applications requiring ultra-high water retention.

[0022] This invention is applicable to all culture systems for synthesizing bacterial cellulose. It synthesizes low-crystallinity bacterial cellulose gels by in-situ addition of a non-carbon source crystallization accumulation regulator. This method has the following advantages compared to existing technologies: 1. This invention requires only a low concentration of non-carbon source crystallization accumulation regulator to significantly reduce the crystallinity of bacterial cellulose, with low reagent dosage and low cost.

[0023] 2. The regulator of this invention does not alter the crystalline form and chemical structure of bacterial cellulose.

[0024] 3. This invention simplifies the process and is compatible with existing procedures by preparing bacterial cellulose with different properties through in-situ control. Conventional techniques for controlling the crystallinity of bacterial cellulose often require post-processing (such as mechanical crushing or chemical cross-linking) or complex blending processes, which are cumbersome and may alter the cellulose crystal structure. This invention achieves in-situ crystallization control by interfering with the arrangement of cellulose molecular chains using a non-carbon source crystallization stacking regulator.

[0025] 4. The low-crystallinity bacterial cellulose synthesized in this invention has significantly improved water-holding capacity, which can expand to more application scenarios.

[0026] The high crystallinity (>80%) of bacterial cellulose leads to poor processing performance and other problems, limiting its application in a wider range of fields such as high water-holding capacity materials and post-processing. This invention reduces crystallinity by adjusting the concentration gradient of a non-carbon source crystallization packing regulator, without altering its crystal form and chemical structure, as shown in the XRD pattern. Figure 2 ) and FTIR spectra ( Figure 5 This significantly improves the water absorption and retention of materials, meeting the needs of more application fields.

[0027] This invention significantly improves upon existing synthetic techniques for bacterial cellulose by regulating in-situ crystallization and stacking, overcoming performance limitations and processing difficulties caused by high crystallinity. It has wide applications in hydrogel materials, high-adsorption materials, and functional membrane materials, such as in mask substrates, BC suspensions, or emulsion particles, offering advantages in environmental friendliness, economy, and functionality. Its core innovation lies in achieving a significant change in bacterial cellulose crystallinity through the addition of small amounts of inexpensive, non-carbon-source crystallization and stacking regulators, providing a novel solution for the efficient production and application expansion of bacterial cellulose, aligning with the concept of green and circular industrial development. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention (the innovation of the present invention is not limited to these examples).

[0029] Figure 1 Photographs of BC gels showing in-situ regulation of bacterial cellulose crystallization properties using different regulators, including (ac) BC-SDBS, (df) BC-MDP, (gi) BC-SMCT, and (jl) BC-PA; the concentrations of the regulators added in each group of images from left to right correspond to 0.05, 0.1, and 0.3 g / L, respectively. Figure 2 XRD patterns of products from bacterial cellulose crystallization properties regulated in situ by different regulators, including a. BC-SDBS, b. BC-MDP, c. BC-SMCT, and d. BC-PA.

[0030] Figure 3 Photograph (a) and SEM image (b) of BC gel synthesized from pure fish tail water (without regulators).

[0031] Figure 4 SEM images of products from bacterial cellulose crystallization properties regulated in situ by different regulators, including (ac) BC-SDBS, (df) BC-MDP, (gi) BC-SMCT, and (jl) BC-PA; the concentrations of the regulators added from left to right in each group of images correspond to 0.05, 0.1, and 0.3 g / L, respectively.

[0032] Figure 5 FTIR spectra of pure BC, BC-SDBS (a), BC-MDP (b), BC-SMCT (c), and BC-PA (d) films. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to better understand the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0034] In this invention, the Acetobacter xylinum strain used for producing bacterial cellulose can be selected from... Komagataeibacter xylinus HN002 (preserved by our team at Hainan University), or commercially available Acetobacter, Acetobacter xylinum strains or other strains capable of biosynthesizing bacterial cellulose that have proper bacterial strain qualifications and can produce bacterial cellulose, can be purchased from other microbial product companies. The following examples all use... Komagataeibacter xylinus HN002 (Collection of our team at Hainan University).

[0035] Example 1 1. Take the tail water from the slaughtering and processing of tilapia in Hainan, pass it through a 100-mesh filter to remove large solid particles such as fish meat scraps, and obtain tilapia processing tail water filtrate.

[0036] 2. Take the above-mentioned wastewater and prepare a bacterial cellulose synthesis medium. If necessary, add an appropriate amount of nitrogen source and / or carbon source to ensure the normal culture requirements of the bacterial cellulose producing strains. Add sodium dodecylbenzenesulfonate (SDBS) at a concentration of 0.05 g / L to the synthesis medium as a non-carbon source crystallization accumulation regulator, and adjust the pH value to 4.5 with acetic acid to obtain the production medium.

[0037] 3. Pass the above-mentioned production culture medium through a 200-mesh filter, pack it into a tray, seal it, and sterilize it at 121℃ for 15 minutes.

[0038] 4. Inoculate the bacterial cellulose synthesis strain with 5 wt% of the production culture medium and statically culture at 30°C for 7 days to obtain bacterial cellulose gel.

[0039] 5. After alkali treatment, the bacterial cellulose gel is rinsed with pure water to remove attached bacteria and other impurities from the gel surface. The appearance of the cleaned bacterial cellulose gel is as follows: Figure 1 As shown, it is a slightly brownish, transparent substance with no odor.

[0040] 6. The above-mentioned bacterial cellulose gel is packaged and sterilized to obtain a low-crystallinity bacterial cellulose product (BC-SDBS-0.05).

[0041] Example 2 1. Take the pig slaughtering and processing wastewater, pass it through a 100-mesh filter to remove large solid particles such as pork scraps, and obtain slaughter wastewater filtrate.

[0042] 2. Take the above-mentioned wastewater and prepare a bacterial cellulose synthesis medium. If necessary, add an appropriate amount of nitrogen source and / or carbon source to ensure the normal culture requirements of the bacterial cellulose producing strains. Add sodium dodecylbenzenesulfonate (SDBS) at a concentration of 0.1 g / L to the synthesis medium as a non-carbon source crystallization accumulation regulator, and adjust the pH value to 4.3 with acetic acid to obtain the production medium.

[0043] 3. Pass the above-mentioned production culture medium through a 200-mesh filter, pack it into a tray, seal it, and sterilize it at 121℃ for 13 minutes.

[0044] 4. Inoculate the bacterial cellulose synthesis strain with 5 wt% of the production culture medium and culture at 35°C for 5 days to obtain bacterial cellulose gel.

[0045] 5. After alkali treatment, the bacterial cellulose gel is rinsed with pure water to remove attached bacteria and other impurities from the gel surface. The appearance of the cleaned bacterial cellulose gel is as follows: Figure 1 As shown, it is a slightly brownish, transparent substance with no odor.

[0046] 6. The above-mentioned bacterial cellulose gel is packaged and sterilized to obtain a low-crystallinity bacterial cellulose product (BC-SDBS-0.1).

[0047] Example 3 1. Take coconut water and let it ferment naturally, then filter it through a 100-mesh screen to remove large solid particles.

[0048] 2. Prepare a bacterial cellulose synthesis medium using the above-mentioned coconut water. If necessary, add an appropriate amount of nitrogen source and / or carbon source to ensure the normal culture requirements of the bacterial cellulose producing strain. Add 0.05 g / L dodecyl phosphate (MDP) to the synthesis medium as a non-carbon source crystallization accumulation regulator, and adjust the pH to 4.2 with acetic acid to obtain the production medium.

[0049] 3. Pass the above-mentioned production culture medium through a 200-mesh filter, pack it into a tray, seal it, and sterilize it at 121℃ for 15 minutes.

[0050] 4. Inoculate the bacterial cellulose synthesis strain with 5 wt% of the production culture medium and culture at 28°C for 9 days to obtain bacterial cellulose gel.

[0051] 5. After alkali treatment, the bacterial cellulose gel is rinsed with pure water to remove attached bacteria and other impurities from the gel surface. The appearance of the cleaned bacterial cellulose gel is as follows: Figure 1 As shown, it is a slightly brownish, transparent substance with no odor.

[0052] 6. The above-mentioned bacterial cellulose gel is packaged and sterilized to obtain a low-crystallinity bacterial cellulose product (BC-MDP-0.05).

[0053] Example 4 1. Take the wastewater from coconut food processing, pass it through a 100-mesh filter to remove large solid particles, and obtain coconut processing wastewater.

[0054] 2. Prepare a bacterial cellulose synthesis medium using the above-mentioned coconut water. If necessary, add an appropriate amount of nitrogen source and / or carbon source to ensure the normal culture requirements of the bacterial cellulose producing strain. Add sodium cocoyl methyl taurate (SMCT) at a concentration of 0.1 g / L to the synthesis medium as a non-carbon source crystallization accumulation regulator. Adjust the pH to 4.0 with acetic acid to obtain the production medium.

[0055] 3. Pass the above-mentioned production culture medium through a 200-mesh filter, pack it into a tray, seal it, and sterilize it at 121℃ for 15 minutes.

[0056] 4. Inoculate the bacterial cellulose synthesis strain with 5 wt% of the production culture medium and culture at 30°C for 7 days to obtain bacterial cellulose gel.

[0057] 5. After alkali treatment, the bacterial cellulose gel is rinsed with pure water to remove attached bacteria and other impurities from the gel surface. The appearance of the cleaned bacterial cellulose gel is as follows: Figure 1 As shown, it is a slightly brownish, transparent substance with no odor.

[0058] 6. The above-mentioned bacterial cellulose gel is packaged and sterilized to obtain a low-crystallinity bacterial cellulose product (BC-SMCT-0.1).

[0059] Example 5 1. Prepare Hestrin-Schramm medium for bacterial cellulose synthesis, adding appropriate amounts of nitrogen and / or carbon sources as needed to ensure the normal culture requirements of the bacterial cellulose-producing strains; add potassium palmitate (PA) at a concentration of 0.3 g / L to the Hestrin-Schramm medium as a non-carbon source crystallization accumulation regulator, and adjust the pH to 4.8 with acetic acid to obtain the production medium.

[0060] 3. Pass the above-mentioned production culture medium through a 200-mesh filter, pack it into a tray, seal it, and sterilize it at 121℃ for 20 minutes.

[0061] 4. Inoculate the bacterial cellulose synthesis strain with 5 wt% of the production culture medium and culture at 30°C for 7 days to obtain bacterial cellulose gel.

[0062] 5. After alkali treatment, the bacterial cellulose gel is rinsed with pure water to remove attached bacteria and other impurities from the gel surface. The appearance of the cleaned bacterial cellulose gel is as follows: Figure 1 As shown, it is a slightly brownish, transparent substance with no odor.

[0063] 6. The above-mentioned bacterial cellulose gel is packaged and sterilized to obtain a low-crystallinity bacterial cellulose product (BC-PA-0.3).

[0064] The low-crystallinity bacterial cellulose product obtained in the above embodiments can be used to prepare water-retaining materials, water-retaining substrates, hydrogel materials, highly adsorbent materials, functional membrane materials, etc., for example, as a mask substrate, or BC suspension or emulsion particles, etc.

[0065] Comparative Example 1 Following the steps of Example 1, without adding a non-carbon source crystallization accumulation regulator, the bacterial cellulose gel was cultured, packaged, and sterilized to obtain the bacterial cellulose product (BC).

[0066] Effects of different preparation methods on the quality of bacterial cellulose Following the methods of Examples 1-5 and the comparative examples, bacterial cellulose gel products were prepared by setting different concentrations of various non-carbon source crystallization packing regulators. The appearance of each gel was photographed and compared, and the crystallinity and water content of different products were measured. Specific results are shown in Tables 1-2 and 1-5. Figure 1-4 For ease of comparison, all treatment groups were incubated at 30°C for 7 days.

[0067] Pure BC, BC-SDBS, BC-MDP, BC-SMCT, and BC-PA film samples were compacted, and their XRD patterns were analyzed using a SmartLab 9kW high-power X-ray diffractometer. The testing conditions were: Cu Kα radiation (λ = 0.154 nm), tube voltage 40 kV, tube current 100 mA, 2θ scan range of 5–40°, scan rate of 5° / min, and step size of 0.01°. The spectra were processed using Jade 9.0 software, and the crystallinity index (Cr1) of the samples was calculated using curve fitting. Specifically, crystallinity is calculated according to the formula: the ratio of the area of ​​the crystalline region to the total area.

[0068] in, Fc The integral area of ​​all crystallization peaks, Fa This represents the integral area of ​​all amorphous peaks.

[0069] The surface morphology of the films was characterized using a Verios G4 UC field emission scanning electron microscope (FESEM). All films were freeze-dried, subjected to liquid nitrogen brittle fracture treatment, and then uniformly coated with a 6 nm thick gold layer for characterization.

[0070] Pure BC, BC-SDBS, BC-MDP, BC-SMCT, and BC-PA membranes were pretreated at 25 °C and 50% relative humidity for 48 h. The membranes were then removed and cut into 2.0 × 4.0 cm strips, and their initial mass was recorded as W0. The membrane samples were then dried at 105 °C for 24 h, and the mass after drying was measured as W1. Each membrane sample was tested three times, and the average value was calculated. The moisture content of the membranes was calculated as follows:

[0071] in, W 0 The initial mass (g) is given. W 1 The mass after drying is (g).

[0072] Table 1. Crystallinity of bacterial cellulose modified in situ by different regulators BC 86.51 BC-SDBS-0.05 82.58 BC-SDBS-0.1 79.26 BC-SDBS-0.3 70.57 BC-MDP-0.05 84.41 BC-MDP-0.1 81.62 BC-MDP-0.3 75.89 BC-SMCT-0.05 84.71 BC-SMCT-0.1 83.07 BC-SMCT-0.3 80.25 BC-PA-0.05 84.40 BC-PA-0.1 81.73 BC-PA-0.3 77.90 Table 2. Moisture content of bacterial cellulose modified in situ with different regulators BC 97.67 BC-SDBS-0.05 98.55 BC-SDBS-0.1 98.89 BC-SDBS-0.3 99.35 BC-MDP-0.05 98.69 BC-MDP-0.1 98.97 BC-MDP-0.3 99.28 BC-SMCT-0.05 98.94 BC-SMCT-0.1 99.01 BC-SMCT-0.3 99.12 BC-PA-0.05 98.47 BC-PA-0.1 98.72 BC-PA-0.3 99.02 Depend on Figure 1-4 As shown in Table 2, the bacterial cellulose gels prepared in Comparative Example 1 and the five examples with added MDP, SMCT, or PA regulators had smooth surfaces and appeared slightly brown and transparent. The gel with added SDBS, however, had an uneven surface and the softest texture, which may be related to its significantly reduced crystallinity. The BC-SDBS, BC-MDP, BC-SMCT, and BC-PA membranes all exhibited typical highly porous three-dimensional network structures. These membranes showed a clear pore distribution on their surfaces, with uneven pore sizes. With increasing surfactant concentration, the pores gradually became looser and larger. This change was closely related to the decrease in crystallinity; the addition of these crystallization packing regulators interfered to some extent with the orderly stacking and assembly process of bacterial cellulose, leading to a decrease in crystallinity, while simultaneously promoting pore expansion and increasing membrane looseness. This structural change further affected the membrane's water-holding capacity.

[0073] X-ray diffraction (XRD) was used to analyze the crystal structures of pure BC, BC-SDBS, BC-MDP, BC-SMCT, and BC-PA membranes to investigate the effects of different non-carbon source crystallization packing regulators on the crystal structure of bacterial cellulose. The XRD results shown in Figure 2 indicate that these membranes all exhibit typical diffraction peaks of cellulose type I, with the strongest peak appearing at 22.8°, corresponding to the (200) plane of cellulose type I. Furthermore, two weaker diffraction peaks were observed at 14.5° and 16.8°, corresponding to the (1-10) and (110) planes of cellulose type I, respectively. These results suggest that the addition of non-carbon source crystallization packing regulators did not alter the crystal form of cellulose. However, the changes in diffraction peak intensity indicate that the non-carbon source crystallization packing regulators influenced the crystallization process of cellulose. The calculation results show that, in Comparative Example 1, without the addition of non-carbon source crystallization stacking regulators, the crystallinity of the bacterial cellulose obtained was as high as 86.51%. However, with the addition of four non-carbon source crystallization stacking regulators, the crystallinity of the cultured bacterial cellulose decreased to varying degrees, and the decrease in crystallinity became more significant with the increase of the amount of non-carbon source crystallization stacking regulators added. This is because these regulators with amphiphilic structures interact with the hydroxyl groups on the surface of the cellulose chains, reducing surface tension and thus hindering the orderly stacking and crystallization between microfibrils. With the increase of regulator concentration, this interference effect becomes more significant, further inhibiting the crystallization between cellulose chains, forming a more disordered structure, and ultimately leading to a decrease in the crystallinity of the cellulose membrane. These amphiphilic regulators can affect the biosynthesis of BC by altering the cell membrane permeability of the strain, promoting BC secretion at a certain concentration, while inhibiting cell growth at higher concentrations, indicating that they affect cell membrane permeability and metabolic activity, and thus may affect the crystallinity of BC. In this study, when the concentration of sodium dodecylbenzenesulfonate (SDBS) was between 0.1 and 0.3 g / L, the crystallinity of bacterial cellulose decreased most significantly, significantly lower than that of Comparative Example 1 and other non-carbon source crystallization packing regulators at the same concentration. The lowest value was achieved at 0.3 g / L, reaching 70.57%. Regarding the water content of the bacterial cellulose gel, the water content of the treatment groups with the addition of the four non-carbon source crystallization packing regulators was significantly increased, significantly higher than that of Comparative Example 1. This demonstrates that the present invention, by adding non-carbon source crystallization packing regulators to the culture medium and utilizing the concentration gradient of the regulators, achieves a bacterial cellulose product that significantly improves the water-holding capacity of the material while reducing crystallinity, while retaining other properties such as high purity and high molecular weight.

[0074] Infrared (IR) structural analysis of bacterial cellulose membranes, such as Figure 5 As shown. Figure 5The FTIR spectra of pure BC, BC-SDBS, BC-MDP, BC-SMCT, and BC-PA films are shown in the 3300-3500 cm⁻¹ range. -1 Within this range, all membranes exhibited distinct absorption peaks, which are caused by the stretching vibrations of the -OH groups. Furthermore, a peak was observed at 2900 cm⁻¹. -1 and 1056 cm -1 The absorption peaks correspond to the asymmetric stretching vibration of -CH2 and the stretching vibration of COC, respectively. These characteristic absorption peaks indicate that the membrane material maintains the typical structure of cellulose, demonstrating that the in-situ added non-carbon source molecular interference agent did not change the chemical structure of bacterial cellulose.

[0075] The specific embodiments of the present invention have been described in detail above, but they are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. A production culture medium for producing bacterial cellulose gel, characterized in that, The production culture medium is a bacterial cellulose culture medium containing 0.05-0.5g of non-carbon source crystallization accumulation regulator per liter.

2. The production culture medium as described in claim 1, characterized in that, The non-carbon source crystallization accumulation regulator is at least one of sodium dodecylbenzenesulfonate, dodecyl phosphate, sodium methyl cocoyl taurate, and / or sodium palmitate; each liter of culture medium contains 0.05-0.3g of the non-carbon source crystallization accumulation regulator; preferably, the bacterial cellulose culture medium is a conventional culture medium used for bacterial cellulose synthesis, and more preferably, naturally fermented coconut water, Hestrin-Schramm standard medium, coconut food processing wastewater, tilapia processing wastewater, livestock and poultry slaughter wastewater, and / or soybean product processing wastewater.

3. A method for producing bacterial cellulose gel, characterized in that, Includes the following steps: (1) Take the production culture medium according to any one of claims 1-4 and adjust the pH value; (2) After inoculating with a bacterial strain that produces bacterial cellulose, bacterial cellulose gel is obtained by culturing.

4. The production method as described in claim 3, characterized in that, In step (1), the production culture medium is supplemented with nitrogen and / or carbon sources according to the requirements of normal bacterial cellulose biosynthesis; the production culture medium is filtered to obtain a clear liquid, which is then sterilized at high temperature and used to culture bacterial cellulose, with the pH adjusted to 3.8-4.8, preferably 4.0-4.5; in step (2), the bacterial strain producing bacterial cellulose can be acetic acid bacteria, xylitol bacteria, or other strains capable of biosynthesizing bacterial cellulose, preferably... Komagataeibacter xylinus HN002.

5. The production method as described in claim 4, characterized in that, In step (1), filtration is performed using a filter screen with a mesh size of 100-200; sterilization is performed using hydrothermal high-temperature sterilization at 121℃ for 10-25 minutes, with the optimal sterilization time being 15 minutes; in step (2), after inoculating with the bacterial cellulose-producing strain, static culture is performed, which is beneficial for the formation of membrane-like bacterial cellulose gel; the culture conditions are: culture at 28-35℃ for 5-10 days.

6. A method for in-situ regulating the crystallinity of bacterial cellulose, characterized in that, Includes the following steps: Bacterial cellulose is produced by fermentation using the production medium described in claim 1 or 2.

7. The application of the production culture medium as described in claim 1 or 2, the production method as described in any one of claims 3-5, or the method for in-situ regulation of bacterial cellulose crystallinity as described in claim 6 in reducing the crystallinity of bacterial cellulose gel and / or increasing the moisture content of bacterial cellulose.

8. The application of the production culture medium as described in claim 1 or 2, the production method as described in any one of claims 3-5, or the method for in-situ regulation of bacterial cellulose crystallinity as described in claim 6 in reducing the crystallinity of bacterial cellulose gel and / or increasing the water content of bacterial cellulose without affecting the crystal form and / or chemical structure of bacterial cellulose.

9. A bacterial cellulose, characterized in that, The culture medium as described in claim 1 or 1, the production method as described in any one of claims 3-5, or the method for in-situ regulation of bacterial cellulose crystallinity as described in claim 6 are used to cultivate the bacteria.

10. The application of bacterial cellulose prepared by the method of claim 6 or 7, or bacterial cellulose as described in claim 9, in the preparation of hydrogel materials, highly adsorbent materials, and / or functional membrane materials.

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