Deep sea parallel type microorganism in-situ pressure-maintaining filtering device and method

Abstract

The invention discloses a deep-sea parallel microorganism in-situ pressure-maintaining filtering device and method. The deep-sea parallel microorganism in-situ pressure-maintaining filtering device comprises a reversing module, a liquid pumping monitoring module and at least one acquisition monitoring module, the reversing module comprises a silt filter, an RNAlater flexible bag and an electromagnetic reversing valve; the liquid pumping monitoring module comprises a first three-way connector, a differential pressure sensor, a pump, an overflow valve and a turbine flowmeter. In the acquisition monitoring module, an inlet of a one-way valve is connected with an outlet of a turbine flowmeter, and an outlet of the one-way valve is connected with an inlet of an intermediate plate on the side surface of the microbial filter through a first stop valve; the microbial filter is provided with a pressure sensor and a piston pressure supplementing device; the inlet end of the piston pressure supplementing device is connected with a second stop valve; bottom and top outlets of the microbial filter are connected with a second three-way connector, and the other end of the second three-way connector is connected with an electromagnetic one-way valve through a third stop valve. By utilizing the method, genetic materials and cell structures of microorganisms can be prevented from being damaged to the maximum extent in the recycling and transferring process.

Description

Technical Field

[0001] The present invention belongs to the field of deep-sea sampling equipment, and in particular relates to a deep-sea parallel microbial in-situ pressure-maintaining filtering device and method. Background Art

[0002] In recent years, with the in-depth development of deep-sea scientific research, deep-sea microbial research has gradually become the focus of scientists. Due to their unique living environment, deep-sea microorganisms have extremely high biodiversity and potential biological activity, and have important scientific research and application value.

[0003] At present, deep-sea microbial collection devices are mainly divided into two categories: one is the traditional deep-sea sampler, which mainly extracts samples from the deep-sea environment through sampling bottles (such as Niskin bottles) and then brings them back to the sea surface for subsequent processing. Since most sampling bottles do not have the function of maintaining pressure, and the concentration of microorganisms in deep sea water is low and the capacity of sampling bottles is limited, the microbial samples may be deactivated due to decompression during the transfer process, thereby affecting the authenticity of the samples and the accuracy of the research results. The other type of equipment is filters, which are usually equipped with multiple layers of filter membranes with different pore sizes (such as SUPR filters), resulting in longer filtration times. In addition, most filters lack in-situ fixation functions, and the genetic material and cell structure of microorganisms are extremely sensitive to time and pressure changes, so they are prone to degradation and damage during recovery and pressure release transfer.

[0004] For example, Chinese patent document with publication number CN116678678A discloses a deep-sea multifunctional dual-cavity sequential sampler, which is composed of multiple dual-cavity sampling bottles and a power supply and control base; Chinese patent document with publication number CN114216742A discloses an integrated system for deep-sea serial seawater fidelity sampling and microbial filtration, which realizes in-situ serial fidelity sampling of seawater at different depths and in-situ filtration of microorganisms by setting up a sampling pump and a number of filtering sampling structures.

[0005] In general, it is difficult for current microbial enrichment devices to collect a large number of samples in a short time under pressure-maintaining conditions and achieve the function of in-situ fixation. Summary of the invention

[0006] The present invention provides a deep-sea parallel microorganism in-situ pressure-maintaining filtration device and method, which can ensure to the greatest extent that the genetic material and cell structure of the microorganisms are not damaged during the recovery and transfer process.

[0007] A deep-sea parallel microbial in-situ pressure-maintaining filtration device comprises a reversing module, a liquid extraction monitoring module and at least one collection monitoring module; when the number of the collection monitoring modules is greater than one, a plurality of collection monitoring modules are connected in parallel to the liquid extraction monitoring module;

[0008] The reversing module includes a sediment filter, an RNAlater flexible capsule, and an electromagnetic reversing valve; wherein the RNAlater flexible capsule and the sediment filter are connected to two inlet ends of the electromagnetic reversing valve;

[0009] The pumping monitoring module includes a first three-way interface, a differential pressure sensor, a pump, a relief valve, and a turbine flowmeter; wherein one end of the first three-way interface is connected to the outlet end of the electromagnetic reversing valve in the reversing module, and the other two ends are connected to the inlet of the differential pressure sensor and the inlet of the pump; the outlet of the differential pressure sensor, the outlet of the pump, the inlet of the relief valve, and the inlet of the turbine flowmeter are connected to the four-way interface; the outlets of the relief valve and the turbine flowmeter are suspended in the air;

[0010] The collection monitoring module includes a one-way valve, a microbial filter, a second three-way interface, and an electromagnetic one-way valve; wherein the inlet of the one-way valve is connected to the outlet of the turbine flowmeter in the liquid extraction monitoring module, and the outlet of the one-way valve is connected to the inlet of the middle plate on the side of the microbial filter through the first stop valve; a pressure sensor and a piston pressure compensation device are installed on the microbial filter, and the inlet end of the piston pressure compensation device is connected to the second stop valve; the bottom and top outlets of the microbial filter are connected to the second three-way interface, and the other end of the second three-way interface is connected to the electromagnetic one-way valve through the third stop valve, and the outlet end of the electromagnetic one-way valve is suspended.

[0011] Furthermore, when the electromagnetic reversing valve is switched to state I, the sediment microorganism filter and the first three-way interface, and the RNAlater flexible capsule and the first three-way interface are disconnected; when the electromagnetic reversing valve is switched to state II, the sediment microorganism filter and the first three-way interface are connected; when switched to state III, the RNAlater flexible capsule and the first three-way interface are connected. State I of the electromagnetic reversing valve and the power-off state of the electromagnetic one-way valve can isolate the inside of the device from the external seawater, preventing contamination of seawater at different levels during deployment and recovery.

[0012] Furthermore, the microbial filter comprises a sealed and fixed first end cover, an intermediate plate and a second end cover; a plurality of membrane frames fixed to the intermediate plate are provided between the first end cover and the intermediate plate, and between the intermediate plate and the second end cover; each membrane frame is provided with a honeycomb-shaped filtering channel, and an O-ring and a filter membrane are provided between two adjacent membrane frames;

[0013] Furthermore, seawater enters from the middle plate inlet on the side of the microbial filter, passes through several membrane frames upward and downward in sequence, and then flows out from the water outlets of the first end cover and the second end cover. A seawater balance channel that penetrates the membrane frame is provided on the outer side of the middle plate to balance the pressure of the seawater flowing upward and downward.

[0014] Furthermore, an annular boss is arranged between two adjacent membrane frames to compress the filter membrane. During filtration, seawater flows through the annular groove formed between the annular bosses, and the pore size of the filter membrane close to the middle plate is larger than the pore size of the filter membrane far from the middle plate.

[0015] A deep-sea parallel microbial in-situ pressure-maintaining filtration method, using the deep-sea parallel microbial in-situ pressure-maintaining filtration device, comprises the following steps:

[0016] S1: Connect all electrical equipment to the external electronic compartment;

[0017] S2: sterilize the entire device, then install the filter membrane of the microbial filter (950) under a sterile process, and fill the RNAlater flexible capsule with RNAlater solution;

[0018] S3: Open the second stop valve, fill with nitrogen at 10% of the pressure at the sampling point, and close the second stop valve after the filling is completed;

[0019] S4: Take out the microbial filter separately and pass deionized water into it to exhaust the air. Pass deionized water into the remaining pipes and assemble them together.

[0020] S5: Place the device at the collection point, open the electromagnetic reversing valve and switch it to the II state, open the electromagnetic one-way valve, and then turn on the pump for filtering, and monitor the filtering state through the turbine flowmeter and the differential pressure sensor;

[0021] S6: After the volume of filtered seawater reaches the required level, the electromagnetic reversing valve is switched to state III, and RNAlater solution begins to be injected;

[0022] S7: When the turbine flowmeter detects that the volume of the injected liquid is approximately 4 times the volume of the microbial filter, the pump and the electromagnetic one-way valve are closed, and the electromagnetic reversing valve is switched to state I; at this time, the in-situ enrichment and fixation of microorganisms at one point are completed;

[0023] S8: If multiple acquisition and monitoring modules are connected in parallel, sequential sampling can be achieved. After completing sampling at one point, just move the entire device to the next sampling point and repeat steps S5-S7;

[0024] S9: Recover the entire device, and the pressure sensor monitors the pressure maintenance status of the microbial filter in real time; the microbial filter is separated from the entire device by closing the first stop valve and the third stop valve. If the pressure sensor reading is smaller than the pressure of the corresponding layer, the second stop valve is opened to inflate the piston pressure replenishing device of the microbial filter to maintain pressure and transfer it.

[0025] The specific process of step S2 is:

[0026] An alcohol solution was introduced from the sediment filter into the entire device to control the forward and reverse rotation of the pump, the reversal of the electromagnetic reversing valve, and the opening and closing of the electromagnetic one-way valve to disinfect the device, and then a large amount of deionized water was introduced for cleaning; the rinsed microbial filter was dried under sterile conditions and the filter membranes were installed in turn; then, the RNAlater flexible bag was filled with RNAlater solution under sterile conditions.

[0027] In step S4, the microbial filter is taken out separately and deionized water is passed through to exhaust the air, specifically:

[0028] After taking out the microbial filter separately, connect the side middle plate inlet and the bottom outlet of the microbial filter to the second three-way interface, and the other end of the second three-way interface is connected to the pump through the third stop valve; after the pump is turned on, deionized water passes through the third stop valve and the second three-way interface in sequence, and then enters from the side and bottom of the microbial filter, and finally the air is discharged from the top.

[0029] In step S5, as the microorganisms accumulate on the filter membrane, the differential pressure sensor connected in parallel to the pump increases, and the flow value fed back by the turbine flowmeter becomes smaller and smaller; when the pressure reaches the opening pressure of the overflow valve, the overflow valve opens and seawater flows out of the overflow valve, thereby protecting the pump.

[0030] In step S8, a multi-channel interface is connected in front of the one-way valve to achieve parallel connection of multiple acquisition and monitoring modules.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention proposes an in-situ fixation scheme, which realizes multi-dimensional monitoring of microbial pressure filtration and fixative injection by adding pressure difference, pressure sensor and turbine flowmeter; the electromagnetic reversing valve switches the flexible bag filled with fixative and the external seawater, so that one pump can complete the functions of filtering and injecting fixative. By proposing a deep parallel microbial in-situ pressure filtration device, high-speed filtration of microorganisms, pressure recovery, and full infiltration of samples by fixative are realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the overall structure of a deep-sea parallel microbial in-situ pressure-maintaining filtration device of the present invention;

[0034] Figure 2 This is a schematic diagram of exhaust of a microbial filter in an embodiment of the present invention;

[0035] Figure 3 This is an assembly appearance diagram of a microbial filter in an embodiment of the present invention;

[0036] Figure 4 An exploded view of the structure of the microbial filter in an embodiment of the present invention;

[0037] Figure 5 It is an enlarged schematic diagram of the cross section of the seawater flow channel inside the microbial filter and the top pressure replenishing structure in the embodiment of the present invention;

[0038] Figure 6 This is a partial enlarged view of the seawater balance channel inside the microbial filter in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0040] like Figure 1 As shown, a deep-sea parallel microbial in-situ pressure-maintaining filtration device has the following overall scheme:

[0041] Seawater enters from the sediment filter 100, and the RNAlater flexible capsule 000 and the sediment filter 100 are connected to the electromagnetic reversing valve 200. The electromagnetic reversing valve 200 is connected to a first three-way interface 300, and the other two ends of the first three-way interface 300 are respectively connected to the differential pressure sensor 400 and the pump 500. The differential pressure sensor 400, the pump 500, the overflow valve 600 and the turbine flowmeter 800 are connected to a four-way interface 700. The other end of the turbine flowmeter 800 is connected to a one-way valve 910, and then connected to the first stop valve 920, and then connected to the middle plate of the microbial filter 950. The microbial filter 950 is loaded with a pressure sensor 930 and a second stop valve 940, and the other two ends of the water outlet are connected to the second three-way interface 960. The second three-way interface 960 is connected to the third stop valve 970, and finally connected to an electromagnetic one-way valve 980.

[0042] like Figure 3 and Figure 4 As shown, in the embodiment of the present invention, the microbial filter 950 includes a first end cover 1, a first membrane frame 2, a second membrane frame 3, a third membrane frame 4, an intermediate plate 5, a fourth membrane frame 6, a fifth membrane frame 7, a sixth membrane frame 8, a second end cover 9, a first locking screw 10, a second locking screw 11, a first O-ring 12, a second O-ring 13, a third O-ring 14, a fourth O-ring 15, a fifth O-ring 16, a pressure sensor 17, a sixth O-ring 18, a retaining ring 19, a piston 20, a seventh O-ring 21, a third locking screw 22, and a third end cover 23.

[0043] Among them, the first membrane frame 2 to the sixth membrane frame 8 are all made of POM material to prevent seawater corrosion and reduce the weight of the equipment. The first O-ring 12, the second O-ring 13, the third O-ring 14, the fourth O-ring 15, the fifth O-ring 16, the sixth O-ring 18, and the seventh O-ring 21 are made of fluororubber material, and the retaining ring 19 is made of polytetrafluoroethylene material. The first end cover 1, the middle plate 5, the second end cover 9, the first locking screw 10, the second locking screw 11, the piston 20, the third locking screw 22, the third end cover 23, and the pressure sensor 17 (housing) are all made of titanium alloy material to ensure structural strength and prevent iron ions from contaminating the sample.

[0044] Excluding the end cap, the overall structure is roughly symmetrically distributed around the middle plate 5. The first membrane frame 2, the second membrane frame 3, the fifth membrane frame 7, and the sixth membrane frame 8 are fixed to the middle plate 5 by twelve first locking screws 10 (including spring washers), and the third membrane frame 4 and the fourth membrane frame 6 are fixed to the middle plate 5 by six second locking screws 11. The first membrane frame 2 and the second membrane frame 3, the second membrane frame 3 and the third membrane frame 4, the fourth membrane frame 6 and the fifth mold frame 7, and the fifth membrane frame 7 and the sixth membrane frame 8 are sealed by two third O-rings 14 and one fourth O-ring 15. The second membrane frame 3, the third membrane frame 4, the fourth membrane frame 6 and the fifth membrane frame 7 are all processed with circular bosses for placing the filter membrane and conveniently pressing it. Honeycomb-shaped filtering channels are opened on the mold frames.

[0045] The filter membrane used in the membrane frame is a polycarbonate filter membrane with a diameter of 142mm, with two layers on the top and bottom, respectively placed between the first membrane frame 2 and the second membrane frame 3, the second membrane frame 3 and the third membrane frame 5, the fourth membrane frame 6 and the fifth mold frame 7, and the fifth membrane frame 7 and the sixth membrane frame 8. The filter membrane is pressed into the annular groove by the sixth O-ring 18 between them. The pore size of the filter membrane close to the middle plate is larger than the pore size of the filter membrane away from the middle plate. A 200-mesh nylon mesh with a diameter of 142mm is placed at the bottom of each layer of the filter membrane, so that the filter membrane can withstand a larger pressure difference during filtration without affecting the filtration quality, and prevent the filter membrane from being damaged when the flow rate is too fast.

[0046] The first end cap 1 and the second end cap 9 of the microbial filter 950 are processed with threads, and the upper and lower bosses of the middle plate 5 are processed with matching threads. The first end cap 1 and the second end cap 9 can be assembled with the middle plate 5 through threads, and the first O-ring 12 and the second O-ring 13 on both sides are compressed for sealing.

[0047] See also Figure 5In addition to the mounting hole and the water outlet of the pressure sensor 17, the first end cover 1 also has a piston pressure-compensating device. Two sets of O-ring grooves are processed on the piston 20 of the piston pressure-compensating device, and a balance hole is drilled between the two grooves to make the piston movement more stable. Each sixth O-ring 18 is equipped with a retaining ring 19 on both sides to improve the sealing performance and extend the service life under the condition of alternating pressure. The top of the piston pressure-compensating device is sealed by a third end cover 23 with two layers of seventh O-rings 21, and the end cover is locked by 8 third locking screws 22 (with elastic washers). Before sampling by the piston pressure-compensating device, nitrogen at 10% of the pressure of the depth to be sampled is introduced into the stop valve above the third end cover 23, and the piston moves downward under the conditions of gravity and pressure. Before diving, the device is filled with deionized water. When the sampler is at the sampling depth, the electromagnetic one-way valve 980 is opened, and seawater enters the sampling chamber under the action of the pump 500, pushing the piston 20 upward and compressing the gas in the energy storage chamber. After the gas pressure is balanced with the external seawater pressure and the volume of the filtered water reaches the requirement, the electromagnetic one-way valve 980 is closed. During the recovery process, the high-pressure gas in the energy storage chamber can compensate for the pressure loss caused by the deformation of the first end cover 1, the second end cover 9 and the third end cover 23.

[0048] See also Figure 5 and Figure 6 , the middle plate 5 has a water inlet, seawater enters from the side, passes through the third membrane frame 4, the second membrane frame 3 and the first membrane frame 2 upwards in sequence, and passes through the fourth membrane frame 6, the fifth membrane frame 7 and the sixth membrane frame 8 downwards in sequence. At this time, seawater can flow out from the outlet of the first end cover 1 and the second end cover 9 or flow into the other side through the seawater balance channel on both sides. The sealing of the balance channel is mainly sealed by the third O-ring 14. The design of the balance channel makes the pressure difference between the inlet and any of the other two outlets consistent, so that seawater or RNAlater fixative can pass through the upper and lower membranes in sequence at the same flow rate, and the effect of filtering or preservation of genetic material is better, reducing the situation where the fixative does not infiltrate the sample and one side of the filter membrane is blocked. In addition, the device needs to be filled with deionized water before deployment, and the design of one inlet and two outlets is convenient for removing the air inside. Before drainage, the piston pressure compensation device is filled with nitrogen, and the piston 20 is located at the bottom. At this time, deionized water can be introduced from the bottom of the second end cover 9 and the outlet of the middle plate 5, and discharged from the channel of the first end cover 1. This design can avoid the installation of a corresponding exhaust valve.

[0049] The specific working process of the device of the present invention is as follows:

[0050] S1: Connect all electrical equipment to the external electronic compartment.

[0051] S2: The entire device is sterilized, and then the filter membrane of the microbial filter 950 is installed under a sterile process, and the RNAlater flexible capsule 000 is filled with RNAlater solution.

[0052] S3: Open the second stop valve 940, fill in nitrogen at 10% of the pressure at the sampling point, and close the second stop valve 940 after the filling is completed.

[0053] S4: Take out the microbial filter 950 separately and pass deionized water into it to exhaust the air. Pass deionized water into the remaining pipelines and then assemble them together.

[0054] S5: Place the device at the collection point, open the electromagnetic reversing valve 200 and switch it to the II state, open the electromagnetic one-way valve 980, and then turn on the pump 500 for filtering, and monitor the filtering state through the turbine flowmeter 800 and the pressure difference sensor 400.

[0055] S6: After the volume of filtered seawater reaches the required level, the electromagnetic reversing valve 200 is switched to the III state, and the RNAlater solution begins to be injected.

[0056] S7: When the turbine flowmeter 800 detects that the volume of the injected liquid is approximately 4 times the volume of the microbial filter 950, the pump 500 and the electromagnetic one-way valve 980 are turned off, and the electromagnetic reversing valve 200 is switched to state I; at this time, the in-situ enrichment and fixation of microorganisms at one point are completed.

[0057] S8: If multiple Figure 1 The pipeline of the acquisition monitoring module shown in the figure can realize sequential sampling. After completing the sampling of one point, just move the entire device to the next sampling point and repeat steps S5-S7.

[0058] S9: Recover the entire device, and the pressure sensor 930 monitors the pressure maintenance status of the microbial filter 950 in real time; the microbial filter 950 is separated from the entire device by closing the first stop valve 920 and the third stop valve 970. If the reading of the pressure sensor 930 is smaller than the pressure of the corresponding layer, the second stop valve 940 is opened to inflate the piston pressure compensation device of the microbial filter 950 to transfer it under pressure.

[0059] In step S2, an alcohol solution can be introduced from the sediment filter 100 to the entire device, and the pump 500 can be controlled to rotate forward and reverse, the electromagnetic reversing valve 200 can be changed, and the electromagnetic check valve 980 can be opened and closed to disinfect the device, and then a large amount of deionized water can be introduced for cleaning. After the rinsed microbial filter 950 is dried under sterile conditions, the filter membranes are sequentially loaded. Then, the RNAlater flexible capsule 000 is filled with RNAlater solution under sterile conditions.

[0060] In step S3, the second stop valve 940 is opened, and nitrogen gas at 10% of the pressure at the sampling point is charged into the piston pressure compensation device. After the charging is completed, the second stop valve 940 is closed.

[0061] In step S4, the microbial filter 950 is taken out separately and deionized water is passed through to remove air. Figure 2 The side middle plate inlet and the bottom outlet of the microbial filter 950 are connected to the second three-way interface 960 , and the other end of the second three-way interface 960 is connected to the pump 500 through the third stop valve 970 .

[0062] After the pump 500 is turned on, the deionized water passes through the third stop valve 970 and the second three-way interface 960 in sequence, and then enters from the side and bottom of the microbial filter 950, and finally the air is discharged from the top. The remaining pipelines are also filled with deionized water and assembled together.

[0063] In step S5, the device is placed at the collection point, the electromagnetic reversing valve 200 is opened and switched to the II state, the electromagnetic one-way valve 980 is opened, and then the pump 500 is turned on for filtering. As the microorganisms accumulate on the filter membrane, the reading of the differential pressure sensor 400 connected in parallel to the pump 500 will increase, and the flow value fed back by the turbine flowmeter 800 will become smaller and smaller. At this time, if the filter membranes on both sides of the microbial filter 950 are blocked in an extreme situation, the value of the differential pressure sensor 400 will rise sharply. When the pressure reaches the opening pressure of the overflow valve 600, the overflow valve 600 opens, and seawater flows out of the overflow valve 600, thereby protecting the pump 500.

[0064] In step S6, when the turbine flowmeter 800 records that the volume of filtered seawater reaches the requirement (≥50 L), the electromagnetic reversing valve 200 is switched to the III state, and the RNAlater solution begins to be injected.

[0065] In step S7, when the turbine flowmeter 800 detects that the volume of the injected liquid is approximately 4 times the volume of the microbial filter 950, the pump 500 and the electromagnetic one-way valve 980 are turned off, and the electromagnetic reversing valve 200 is switched to the I state. At this time, the in-situ enrichment and fixation of microorganisms at a point are completed. The I state of the electromagnetic reversing valve 200 and the power-off state of the electromagnetic one-way valve 980 can isolate the inside of the device from the external seawater, preventing the contamination of seawater at different levels during the deployment and recovery process.

[0066] In step S8, another branch can be formed by adding a one-way valve 910, a first stop valve 920, a pressure sensor 930, a second stop valve 940, a microbial filter 950, a second three-way interface 960, a third stop valve 970 and an electromagnetic one-way valve 980. It is only necessary to connect a multi-way interface in front of the one-way valve 910.

[0067] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A deep-sea parallel microbial in-situ pressure-maintaining filtration device, characterized in that: It includes a reversing module, a liquid extraction monitoring module and at least one collection monitoring module; when the number of the collection monitoring modules is greater than one, multiple collection monitoring modules are connected in parallel to the liquid extraction monitoring module; The reversing module comprises a sediment filter (100), an RNAlater flexible capsule (000), and an electromagnetic reversing valve (200); wherein the RNAlater flexible capsule (000) and the sediment filter (100) are connected to two inlet ends of the electromagnetic reversing valve (200); The liquid extraction monitoring module comprises a first three-way interface (300), a pressure difference sensor (400), a pump (500), a relief valve (600), and a turbine flowmeter (800); wherein one end of the first three-way interface (300) is connected to the outlet end of the electromagnetic reversing valve (200) in the reversing module, and the other two ends are connected to the inlet of the pressure difference sensor (400) and the inlet of the pump (500); the outlet of the pressure difference sensor (400), the outlet of the pump (500), the inlet of the relief valve (600), and the inlet of the turbine flowmeter (800) are connected to the four-way interface (700); and the outlets of the relief valve (600) and the turbine flowmeter (800) are suspended in the air; The collection monitoring module comprises a one-way valve (910), a microbial filter (950), a second three-way interface (960), and an electromagnetic one-way valve (980); wherein the inlet of the one-way valve (910) is connected to the outlet of the turbine flowmeter (800) in the liquid extraction monitoring module, and the outlet of the one-way valve (910) is connected to the inlet of the middle plate on the side of the microbial filter (950) through the first stop valve (920); the microbial filter (950) is equipped with a pressure sensor (930) and a piston pressure compensation device, and the inlet end of the piston pressure compensation device is connected to the second stop valve (940); the bottom and top outlets of the microbial filter (950) are connected to the second three-way interface (960), and the other end of the second three-way interface (960) is connected to the electromagnetic one-way valve (980) through the third stop valve (970), and the outlet end of the electromagnetic one-way valve (980) is suspended in the air.

2. The deep-sea parallel microbial in-situ pressure-maintaining filtration device according to claim 1, characterized in that: When the electromagnetic reversing valve (200) is switched to state I, the sediment microorganism filter (100) and the first three-way interface (300) are disconnected, as are the RNAlater flexible capsule (000) and the first three-way interface (300); when the electromagnetic reversing valve (200) is switched to state II, the sediment microorganism filter (100) and the first three-way interface (300) are connected; when the electromagnetic reversing valve (200) is switched to state III, the RNAlater flexible capsule (000) and the first three-way interface (300) are connected.

3. The deep-sea parallel microbial in-situ pressure-maintaining filtration device according to claim 1, characterized in that: The microbial filter (950) comprises a sealed and fixed first end cover (1), an intermediate plate (5) and a second end cover (9); a plurality of membrane frames fixed to the intermediate plate (5) are provided between the first end cover (1) and the intermediate plate (5), and between the intermediate plate (5) and the second end cover (9); each membrane frame is provided with a honeycomb-shaped filtering channel, and an O-ring and a filter membrane are provided between two adjacent membrane frames.

4. The deep-sea parallel microbial in-situ pressure-maintaining filtration device according to claim 3 is characterized in that: Seawater enters from the inlet of the middle plate (5) on the side of the microbial filter (950), passes through a plurality of membrane frames in sequence upward and downward, and then flows out from the water outlets of the first end cover and the second end cover. A seawater balance channel penetrating the membrane frame is provided on the outer side of the middle plate (5) for balancing the pressure of the seawater flowing upward and downward.

5. The deep-sea parallel microbial in-situ pressure-maintaining filtration device according to claim 3 is characterized in that: An annular boss is arranged between two adjacent membrane frames to compress the filter membrane. During filtration, seawater flows through the annular groove formed between the annular bosses. The pore size of the filter membrane close to the middle plate (5) is larger than the pore size of the filter membrane far from the middle plate (5).

6. A deep-sea parallel microbial in-situ pressure-maintaining filtration method, characterized in that: The use of the deep-sea parallel microbial in-situ pressure-maintaining filtration device according to any one of claims 1 to 5 comprises the following steps: S1: Connect all electrical equipment to the external electronic compartment; S2: sterilize the entire device, then install the filter membrane of the microbial filter (950) under a sterile process, and fill the RNAlater flexible capsule (000) with RNAlater solution; S3: Open the second stop valve (940), charge nitrogen gas at 10% of the pressure at the sampling point, and close the second stop valve (940) after charging is completed; S4: Take out the microbial filter (950) and pass deionized water into it to exhaust the air. Pass deionized water into the remaining pipes and assemble them together. S5: The device is placed at the collection point, the electromagnetic reversing valve (200) is opened to switch to the II state, the electromagnetic one-way valve (980) is opened, and then the pump (500) is turned on for filtering, and the filtering state is monitored through the turbine flow meter (800) and the pressure difference sensor (400); S6: After the volume of filtered seawater reaches the required level, the electromagnetic reversing valve (200) is switched to state III, and the RNAlater solution begins to be injected; S7: When the turbine flowmeter (800) detects that the volume of the injected liquid is approximately 4 times the volume of the microbial filter (950), the pump (500) and the electromagnetic one-way valve (980) are turned off, and the electromagnetic reversing valve (200) is switched to state I; at this time, the in-situ enrichment and fixation of microorganisms at one point are completed; S8: Multiple acquisition and monitoring modules can be connected in parallel to achieve sequential sampling; after completing sampling at one point, just move the entire device to the next sampling point and repeat steps S5-S7; S9: The entire device is recovered, and the pressure sensor (930) monitors the pressure maintenance status of the microbial filter (950) in real time; the microbial filter (950) is separated from the entire device by closing the first stop valve (920) and the third stop valve (970). If the reading of the pressure sensor (930) is smaller than the pressure of the corresponding layer, the second stop valve (940) is opened to inflate the piston pressure compensation device of the microbial filter (950) to compensate for the pressure, and the microbial filter (950) is transferred under pressure.

7. The deep-sea parallel microbial in-situ pressure-maintaining filtration method according to claim 6, characterized in that: The specific process of step S2 is: An alcohol solution is introduced into the whole device from the sediment filter (100), and the pump (500) is controlled to rotate forward and reverse, the electromagnetic reversing valve (200) is controlled to change direction, and the electromagnetic check valve (980) is controlled to open and close, so as to disinfect the device, and then a large amount of deionized water is introduced for cleaning; the rinsed microbial filter (950) is dried under sterile conditions, and then filter membranes are installed in sequence; and then the RNAlater flexible capsule (000) is filled with RNAlater solution under sterile conditions.

8. The deep-sea parallel microbial in-situ pressure-maintaining filtration method according to claim 6, characterized in that: In step S4, the microbial filter (950) is taken out separately and deionized water is introduced to exhaust the air, specifically: After the microbial filter (950) is taken out separately, the side middle plate inlet and the bottom outlet of the microbial filter (950) are connected to the second three-way interface (960), and the other end of the second three-way interface (960) is connected to the pump (500) through the third stop valve (970); after the pump (500) is turned on, deionized water passes through the third stop valve (970) and the second three-way interface (960) in sequence, and then enters from the side and bottom of the microbial filter (950), and finally the air is discharged from the top.

9. The deep-sea parallel microbial in-situ pressure-maintaining filtration method according to claim 6, characterized in that: In step S5, as the microorganisms accumulate on the filter membrane, the reading of the differential pressure sensor (400) connected in parallel to the pump (500) increases, and the flow value fed back by the turbine flowmeter (800) becomes smaller and smaller; when the pressure reaches the opening pressure of the overflow valve (600), the overflow valve (600) opens, and seawater flows out of the overflow valve (600), thereby protecting the pump (500).

10. The deep-sea parallel microbial in-situ pressure-maintaining filtration method according to claim 6, characterized in that: In step S8, a multi-channel interface is connected in front of the one-way valve (910) to achieve parallel connection of multiple acquisition and monitoring modules.

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