A bio-cellulose fermentation apparatus and a method for producing bio-cellulose using the same

Abstract

The present application relates to a kind of biological cellulose fermentation equipment and the method for producing biological cellulose with the equipment.The equipment includes fermentation tank body, culture solution storage tank body, multiple spray nozzles arranged on the inner wall of fermentation chamber, and fermentation central axis made of porous rough material etc..Through the equipment, the separate temperature control of fermentation chamber and culture solution storage chamber and the continuous fermentation of biological cellulose on fermentation central axis are realized, which greatly improves production efficiency and reduces production cost.

Description

Technical Field

[0001] This invention relates to equipment and methods for producing bio-fermentation materials, and more particularly to a bio-cellulose fermentation apparatus and a method for producing bio-cellulose using the apparatus. Background Technology

[0002] Biological cellulose (also known as bacterial cellulose, BC) refers to cellulose produced by the fermentation of certain specific bacteria under different conditions. Biological cellulose shares the same molecular structural units as natural cellulose, but it also possesses many unique properties. First, compared to plant cellulose, it lacks byproducts such as lignin, pectin, and hemicellulose, exhibiting high crystallinity and high degree of polymerization. Second, it possesses an ultra-fine spatial network structure, consisting of fiber bundles composed of microfibers with a diameter of 3-4 nanometers, interwoven to form a well-developed ultra-fine network structure. Furthermore, it has an elastic modulus several times, even tens of times, greater than that of plant fibers, and also exhibits higher tensile strength. It also possesses strong water-holding capacity and good biocompatibility, adaptability, and biodegradability. Due to these advantages, biological cellulose materials have been widely used in various fields such as food, medicine, cosmetics, and biomaterials.

[0003] The production of bio-cellulose mainly involves cultivating bacteria such as *Acetobacter* to metabolize bio-cellulose. This includes static fermentation and dynamic fermentation. Static fermentation involves culturing bio-cellulose-producing bacteria in a static liquid culture medium, which forms a gel-like bio-cellulose gel product at the gas-liquid interface between the liquid medium and air. Dynamic fermentation, on the other hand, involves fermentation in a stirred or shaken flask to produce bio-cellulose. However, due to limitations in yield and product physicochemical properties, static fermentation is currently the primary method used to prepare bio-cellulose hydrogels.

[0004] Currently, the commonly used static fermentation equipment for bio-cellulose production is relatively simple, typically involving shallow trays filled with liquid culture medium, inoculated with microorganisms, and then fermentation. A major problem is that as a bio-cellulose hydrogel film forms on the surface of the culture medium during fermentation, it gradually isolates the oxygen necessary for the growth and reproduction of the bio-cellulose-producing bacteria. Therefore, once the bio-cellulose hydrogel reaches a certain thickness, the bacteria can no longer grow, significantly limiting the production efficiency of bio-cellulose. For example, CN107446796A discloses a bacterial cellulose fermentation production device, also for static fermentation, which improves production efficiency by setting up multiple culture boxes (similar to shallow trays) stacked on top of each other. However, this still does not fundamentally solve the oxygen supply problem, and its production efficiency and cost remain high. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a bio-cellulose fermentation device and a method for producing bio-cellulose using the device. This breaks away from the traditional method of using shallow tray static fermentation culture for bio-cellulose, adopts a design more suitable for industrialization, greatly improves the production efficiency of bio-cellulose, and reduces production costs.

[0006] This invention provides a bio-cellulose fermentation device, comprising a fermentation tank and a culture medium storage tank, which are stacked one on top of the other and supported and fixed by support legs. The fermentation tank forms a fermentation chamber, and the culture medium storage tank forms a culture medium storage chamber. The fermentation chamber is connected to the culture medium storage chamber through a through hole. Multiple spray nozzles are provided on the inner wall of the fermentation chamber and are connected to the culture medium storage chamber through pipelines. The top of the fermentation chamber is connected to a fermentation central axis located in the middle by a fixing rod. The fermentation central axis is made of a porous, rough material with good water absorption.

[0007] There are no particular limitations on the porous rough material with good water absorption, as long as it has good water absorption, can adsorb the culture medium to enable microorganisms to ferment and produce bio-cellulose hydrogel, and its roughness allows the produced bio-cellulose hydrogel to be adsorbed on the fermentation axis. Examples of porous rough materials include ceramic materials or zeolite materials.

[0008] There is no particular limitation on the number of spray nozzles; their number can be selected and adjusted according to the length of the fermentation axis, ensuring that the culture medium is sprayed onto the fermentation axis in a mist form. For example, at least four nozzles can be used.

[0009] A conical baffle is also provided between the fixed rod and the fermentation axis, with its lower edge width greater than the diameter of the fermentation axis. This conical baffle prevents the culture medium sprayed onto the upper part of the connecting rod from remaining and fermenting, thus avoiding the formation of large amounts of bio-cellulose hydrogel on the fermentation axis and making harvesting difficult. Even if the culture medium is sprayed onto the upper part of the connecting rod, it will flow down and drip due to gravity, thereby preventing the formation of bio-cellulose hydrogel on it.

[0010] The fermenter also features a covered culture medium inlet at the top. This inlet allows the culture medium to be poured into the fermentation chamber before fermentation begins, and then flows through a perforation into the culture medium storage chamber. After the culture medium is poured in, the lid can be closed to ensure the cleanliness of the fermentation chamber.

[0011] Both the fermentation tank and the culture medium storage tank are hollow jacketed structures, each with an inlet and an outlet on its outer wall. Hot water is circulated through the inlets and outlets on the outer wall of the fermentation tank, circulating inside the hollow jacket to maintain the temperature within the fermentation chamber at the desired fermentation temperature. Conversely, cold water is circulated through the inlets and outlets on the outer wall of the culture medium storage tank, circulating inside the hollow jacket to maintain the temperature within the culture medium storage chamber at a level significantly lower than the fermentation temperature. This prevents the formation of bio-cellulose hydrogels during microbial fermentation, ensuring the culture medium remains in a liquid state. The temperatures within the fermentation chamber and culture medium storage chamber can be selected based on the optimal temperature for bio-cellulose-producing bacteria, such as 25-30°C or below 15°C. It should be noted that the circulation of hot and cold water is not strictly necessary; the choice between using only hot water, only cold water, or both can be made depending on the ambient temperature at the time of production.

[0012] To transport and control the spraying of the culture medium, the pipeline is equipped with a pump and a solenoid valve. The culture medium is sprayed onto the fermentation axis through a spray nozzle. The fermentation axis absorbs some of the culture medium, and the excess culture medium drips down and flows back to the culture medium storage chamber through a through-hole. The culture medium adsorbed on the fermentation axis is in a static state. Under suitable temperature and oxygen conditions, it will ferment to produce bio-cellulose hydrogel, which will adsorb onto the outer surface of the fermentation axis and encapsulate it. Since the bio-cellulose hydrogel itself also has adsorption properties, its outer surface can re-adsorb the sprayed culture medium and undergo re-fermentation under suitable temperature and oxygen conditions, thereby continuously producing bio-cellulose hydrogel and increasing the thickness of the bio-cellulose hydrogel on the fermentation axis. Although the excess culture medium is in the fermentation chamber, i.e., under suitable temperature and oxygen conditions, it is constantly flowing and flows out of the fermentation chamber in a very short time. Therefore, it will not ferment to produce bio-cellulose hydrogel and will always remain in a liquid state.

[0013] Because fermentation always takes place outside the central axis or hydrogel, it will not be interrupted due to lack of oxygen as in traditional shallow tray fermentation. As long as there is always air in the fermentation chamber, fermentation can continue uninterrupted. Of course, to improve fermentation efficiency, oxygen supply equipment can also be used to supply oxygen to the fermentation chamber.

[0014] It is easy to understand that although the spray nozzles can spray continuously, for energy-saving reasons, they can also be used intermittently as needed, as long as it does not affect the fermentation on the central axis of fermentation.

[0015] To facilitate the harvesting of the generated bio-cellulose hydrogel, a detachable connection can be made between the top and side walls of the fermentation tank (not shown in the attached figure), allowing the top of the fermentation tank to be opened and the bio-cellulose hydrogel on the fermentation axis to be removed.

[0016] The present invention further provides a method for producing biocellulose using the aforementioned biocellulose fermentation equipment, comprising the following steps: Cellulose-producing bacteria are inoculated into sterilized liquid culture medium to prepare a culture solution. The culture solution is poured into the fermentation chamber through the culture solution inlet and flows into the culture solution storage chamber through the pores. The culture medium is transported from the culture medium storage chamber to the spray nozzle through a pipeline, and then sprayed onto the fermentation axis made of porous rough material through the spray nozzle. Excess culture medium flows back to the culture medium storage chamber through the through hole. Hot and cold water are circulated into the hollow jackets of the fermentation tank and the culture medium storage tank through the inlet and outlet respectively to control the temperature of the fermentation chamber and the culture medium storage chamber for fermentation. Open the top of the fermentation tank and collect the resulting bio-cellulose hydrogel product from the fermentation axis.

[0017] In the method for producing bio-cellulose, the culture medium is delivered to the spray nozzle through pipelines and pumps and solenoid valves installed therein, and sprayed intermittently; the temperature in the fermentation chamber is controlled at a fermentation temperature of 25-30°C by circulating hot water into the hollow jacket of the fermentation tank; and the temperature in the culture medium storage chamber is controlled at 5-15°C below the fermentation temperature by circulating cold water into the hollow jacket of the culture medium storage tank.

[0018] It is easy to understand that, for the purpose of easy monitoring, monitoring equipment such as thermometers, hygrometers and their sensors can be installed in the fermentation room and culture medium storage room as needed.

[0019] This invention breaks away from the traditional shallow-pan fermentation method commonly used in static fermentation. It fully utilizes the adsorption properties of the bio-cellulose hydrogel itself to design the equipment and method described in this invention. By separately controlling the temperature of the fermentation chamber and the culture medium storage chamber, it achieves continuous industrial production of bio-cellulose hydrogels, significantly improving production efficiency and substantially reducing production costs. By setting up multiple such fermentation devices in a factory, the production of medium-scale bio-cellulose gel products can be fully met. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the structure of the bio-cellulose fermentation equipment of the present invention; wherein: 1-fermentation tank; 2-culture medium storage tank; 3-support leg; 4-water inlet; 5-water outlet; 6-fermentation chamber; 7-culture medium storage chamber; 8-through hole; 9-spray nozzle; 10-pipeline; 11-fermentation central axis; 12-fixing rod; 13-culture medium inlet; 14-conical baffle. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it is readily understood that the specific embodiments described below are merely illustrative examples of the invention and should not be construed as limiting the invention. Any modifications or adjustments that do not depart from the scope of the invention are within the scope of the invention. Example 1:

[0022] According to the appendix of this invention Figure 1 The structure shown provides the bio-cellulose fermentation apparatus of this embodiment, wherein the fermentation axis 11 is made of zeolite material; and there are four spray nozzles.

[0023] A culture medium containing cellulose-producing bacteria (Acetobacter xylinum) is prepared by inoculating sterilized liquid coconut water culture medium. The culture medium is then poured into fermentation chamber 6 through culture medium inlet 13 and flows into culture medium storage chamber 7 through through hole 8. The culture medium is then transported from culture medium storage chamber 7 to spray nozzle 9 through pipeline 10. The culture medium is then sprayed onto fermentation central axis 11 made of porous rough material through spray nozzle 9 and sprayed continuously. Excess culture medium flows back to culture medium storage chamber 7 through through hole 8. Hot water and cold water are circulated into the hollow jacket of fermentation tank 1 and culture medium storage tank 2 through water inlet 4 and water outlet 5, respectively. The temperatures of fermentation chamber and culture medium storage chamber are controlled at 28°C and 10°C, respectively. After 5 days of fermentation, the top of fermentation tank 1 is opened, and the produced cellulose hydrogel product is collected from fermentation central axis 11. Example 2:

[0024] According to the appendix of this invention Figure 1 The structure shown provides the bio-cellulose fermentation apparatus of this embodiment, wherein the fermentation axis 11 is made of ceramic material; and there are six spray nozzles.

[0025] A culture medium containing bio-cellulose-producing bacteria (kombucha) is inoculated into a sterilized liquid molasses culture medium. The culture medium is then poured into the fermentation chamber 6 through the culture medium inlet 13 and flows into the culture medium storage chamber 7 through the through hole 8. The culture medium is then transported from the culture medium storage chamber 7 to the spray nozzle 9 through the pipeline 10. The culture medium is then sprayed onto the fermentation axis 11, which is made of porous rough material, through the spray nozzle 9. The spray is intermittently operated by a solenoid valve, spraying for 1 minute every 5 minutes. Excess culture medium flows back to the culture medium storage chamber 7 through the through hole 8. Hot water and cold water are circulated into the hollow jackets of the fermentation tank 1 and the culture medium storage tank 2 through the water inlet 4 and the water outlet 5, respectively. The temperatures of the fermentation chamber and the culture medium storage chamber are controlled at 26°C and 15°C, respectively. After 7 days of fermentation, the top of the fermentation tank 1 is opened, and the bio-cellulose hydrogel product produced is collected from the fermentation axis 11.

[0026] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A bio-cellulose fermentation device, characterized in that: The fermentation tank (1) and the culture medium storage tank (2) are stacked on top of each other and supported and fixed by support legs (3). The fermentation tank forms a fermentation chamber (6) and the culture medium storage tank forms a culture medium storage chamber (7). The fermentation chamber (6) is connected to the culture medium storage chamber (7) through a through hole (8). Multiple spray nozzles (9) are provided on the inner wall of the fermentation chamber (6) and are connected to the culture medium storage chamber (7) through pipelines (10). The top of the fermentation chamber (6) is connected to the fermentation central axis (11) set in the middle through a fixing rod (12). The fermentation central axis is made of a porous rough material with good water absorption.

2. The bio-cellulose fermentation equipment according to claim 1, characterized in that: The porous, rough material with good water absorption is a ceramic material or a zeolite material.

3. The bio-cellulose fermentation equipment according to claim 1, characterized in that: The number of spray nozzles (9) is at least 4.

4. The bio-cellulose fermentation equipment according to claim 3, characterized in that: A conical baffle (14) is also provided between the fixed rod (12) and the fermentation shaft (11), the width of which is greater than the diameter of the fermentation shaft.

5. The bio-cellulose fermentation equipment according to any one of claims 1-3, characterized in that: The fermentation tank (1) is also provided with a covered culture medium inlet (13) at the top.

6. The bio-cellulose fermentation equipment according to any one of claims 1-3, characterized in that: Both the fermentation tank (1) and the culture medium storage tank (2) are hollow jacket structures, and both have water inlets (4) and water outlets (5) on their outer walls. Hot water is circulated inside the hollow jacket of the fermentation tank (1) through the water inlets (4) and water outlets (5) on the outer wall of the fermentation tank (1). Cold water is circulated inside the hollow jacket of the culture medium storage tank (2) through the water inlets (4) and water outlets (5) on the outer wall of the culture medium storage tank (2).

7. The biocellulose fermentation equipment according to claim 5, characterized in that: The pipeline (10) is also equipped with a pump and a solenoid valve to control the intermittent spraying of the spray nozzle (9).

8. The bio-cellulose fermentation equipment according to any one of claims 1-3, characterized in that: The top and side walls of the fermentation tank (1) are detachably connected.

9. A method for producing biocellulose using the biocellulose fermentation equipment according to any one of claims 1-8, characterized in that: Includes the following steps: 1) Inoculate the sterilized liquid culture medium with bio-cellulose-producing bacteria to make a culture solution. Pour the culture solution into the fermentation chamber (6) through the culture solution inlet (13) and into the culture solution storage chamber (7) through the through hole (8). 2) The culture medium is transported from the culture medium storage chamber (7) to the spray nozzle (9) through the pipeline (10), and then the culture medium is sprayed onto the fermentation shaft (11) made of porous rough material through the spray nozzle (9). Excess culture medium flows back to the culture medium storage chamber (7) through the through hole (8). 3) Hot water and cold water are circulated into the hollow jacket of the fermentation tank (1) and the culture medium storage tank (2) through the inlet (4) and outlet (5) respectively to control the temperature of the fermentation chamber and the culture medium storage chamber and carry out fermentation; 4) Open the top of the fermentation tank (1) and collect the generated bio-cellulose hydrogel product from the fermentation axis (11).

10. The method for producing bio-cellulose according to claim 9, characterized in that: The culture medium is delivered to the spray nozzle (9) through pipelines and pumps and solenoid valves installed therein, and sprayed intermittently; the temperature in the fermentation chamber (6) is controlled at 25-30℃ by circulating hot water into the hollow jacket of the fermentation tank (1); the temperature in the culture medium storage chamber (7) is controlled at 5-15℃ lower than the fermentation temperature by circulating cold water into the hollow jacket of the culture medium storage tank (2).

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