JPS6178375A - Method for separating and recovering aquatic bacteria - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an apparatus for separating and recovering aquatic bacteria or microorganisms that react to a magnetic field.

[Background of the invention]

Among the organisms that sense the earth's magnetic field, aquatic bacteria called magnetotactic bacteria have multiple single-crystal magnetites (Fe, O,
), and is said to travel in the direction of a specific magnetic pole due to the action of its magnetic substance. These aquatic bacteria live in the soil of freshwater and seawater, and use this soil as a base for their growth. Therefore, in order to obtain υ1 of this aquatic bacterium, it is necessary to separate it from sediments such as soil. In this separation method, a solution containing aquatic bacteria and sediment is placed in a non-magnetic container, left to stand, and a magnetic field is applied to the outer periphery of the container at an arbitrary position in the -LKl liquid part to collect the liquid near the magnetic pole (T, ToMoench
at al, , Arch, Microbiol,
, vol. IIL 1978), or a solution containing aquatic bacteria and precipitate is brought into contact with clear water such as distilled water on a glass plate, and a magnetic field is applied to make the aquatic bacteria swim toward the clear water (R, P, nlakemoroe
tal, Science, February 1982 issue, p16
~25) There are examples. However, these methods cannot be said to be effective separation methods because it is difficult to sufficiently recover the bacteria to be recovered from the solution, and the throughput is small.

[Purpose of the invention]

An object of the present invention is to provide a separation and recovery method that continuously separates aquatic bacteria that sense a magnetic field from sedimentary substances, and improves the recovery rate of aquatic bacteria that are mobile toward am. .

[Summary of the invention]

The present invention provides a separator made of non-magnetic material within a magnetic field, supplies a solution containing aquatic bacteria that react to the magnetic field and sedimentary substances from one end of the separator, and allows only the sedimentary substances to settle by gravity at the bottom of the separator. , is characterized by efficiently collecting aquatic bacteria that react to a magnetic field from one outlet of the separator.

[Embodiments of the invention]

Aquatic bacteria that respond to magnetic fields and travel in the direction of specific magnetic poles, that is, magnetotactic bacteria, live in soil. Furthermore, according to experiments conducted by the present inventors, it was predicted that when culturing this magnetotactic bacterium, sedimentary solids such as soil would affect its growth efficiency.

Therefore, in order to extract magnetotactic bacteria, they must be separated from the sedimentary solid material. Conventionally, methods such as centrifugal separation and selective extraction using a micromanipulator are known for separating and extracting microorganisms and the like. However, according to the experience of the present inventors, excessive agitation induces dysfunction of magnetotactic bacteria and tends to reduce the number of bacteria, so centrifugation is not suitable for separating and extracting magnetotactic bacteria. considered unsuitable. Also,
The selective extraction method extracts only a small number of bacteria per hour, so it cannot be said to be an effective separation and extraction method. Therefore, there is a need for a method for separating and extracting magnetotactic bacteria that does not adversely affect the bacteria and can be processed through a large amount.

The present invention was achieved based on the above experimental experience.

One embodiment is shown in FIG. In Fig. 1, 1 is a separator with a non-magnetic material having three flow pipes, 2 and 2' are magnets forming opposite poles, 3 is a solids collector, 4 is a bacteria collector, 5 is a solution supply device, 6 is an auxiliary liquid supply device, 7 is a solid matter discharge device, and 8 is a sealing plug. A liquid 9 containing magnetotactic aquatic bacteria and sedimentary solid substances is fed by a solution supply device 5 to the separator 1 through a conduit 12 from a flow tube IA. Separator 1 is T
It forms a letter shape, and the straight flow parts IA and IB are positioned horizontally. Magnets 2 and 2' are installed before and after this straight flow section so that the magnetic poles of their opposing surfaces are different. The magnets 2, 2' may be electromagnets or permanent magnets, and the magnetic poles on which the magnetotactic aquatic bacteria to be collected travel are located in the flow direction of the separator 1, that is, in the magnet 2'. The sedimentary solid substances in the solution 9 fed into the separator 1 are pushed forward while accumulating at the bottom near the flow path IA. In the T-shaped part of the separator 1, that is, the separation part, the solid substances settled by gravity settle in the flow pipe IC provided in the vertical direction.

On the other hand, since the magnetotactic aquatic bacteria in the solution have a strong magnetic force and move in the direction of a specific magnetic pole, they are separated from the sedimentary solid material at the T-shaped portion and move toward the magnet 2' through the flow pipe IB. In this case, if the position where the magnetic field strength is maximum is located above the hard-field interface of the flow pipe IA, the magnetotactic aquatic bacteria can be effectively moved. The magnetotactic aquatic bacteria that have reached the outlet of the flow tube IB do not stay in the separation tube 1 within the magnetic field and are transferred to the solution supply bag W.
5 and collected in a conduit 14 into a bacteria collector 14 . The solid matter that has settled by gravity in the flow path IC is accumulated in the solid matter collector 3 through the conduit 13. By the way, if the gas phase is mixed in the flow paths IC and 13 from the solids collector 3 to the separation section of the separator 1, it will become an obstacle to sedimentation and the solids will not be separated. For this reason,
A sealing stopper 8 is provided in the solid matter recovery device 3, and when gas is mixed in, liquid is supplied from an auxiliary liquid supply device 6, and the gas is removed from the flow path.

This operation only needs to be performed once before supplying the solution 9, but if gas gets mixed in while the solution supply bag W5 is in operation, the supply bag W5
It is necessary to stop and do this. The liquid from the supply device 6 may be any liquid as long as it does not affect magnetotactic aquatic bacteria, and is generally a clear liquid of the target solution 9 or distilled water adjusted to the same pi value as the target solution 9. Furthermore, by intermittently or continuously extracting the solids accumulated in the solids collector 3 with the discharge device 7, it is possible to continuously supply the separation target solution 9 and collect magnetotactic aquatic bacteria over a long period of time. In this case, the flow rate outflow from the solid matter discharge device 7 needs to be smaller than the flow rate inflow into the solution supply device 5.

Based on this example, the present inventors conducted a separation and recovery experiment of magnetotactic aquatic bacteria, and as a result, a recovery efficiency of more than 80% was obtained. The experiment used a tubular separator with a diameter of 5 mm, and
Solutions containing 0% sedimentable solids were targeted. Also,
According to experiments, although the liquid flow rate in the separator affects the sedimentation separation of solids, it has been found that clear separation can be achieved up to about 20 cn/win. This separation of solid substances can be effected well by adjusting the diameters of the flow tubes IA and IB for magnetotactic aquatic bacteria and the flow tube IC for settled solid substances.

In FIG. 1, the flow tubes IA and IB for magnetotactic aquatic bacteria of the separator 1 are positioned horizontally, but they may be tilted. Regarding the inclination, either the flow pipe IA or IB may be made higher, but as shown in FIG. 2, it is more effective to make the flow pipe IB higher. This is because if the flow pipe IA is made high, the liquid flow rate in the separator will be accelerated, and there is also a risk that a gas phase will be formed in the flow pipe IA or IB and the interface between the solid and liquid phases will be disturbed. be. If the flow tube IB is high, the solid and liquid phases are not disturbed and the collection efficiency of magnetotactic aquatic bacteria is not adversely affected. The angle of inclination of the separator 1 is limited by the condition that the feed solution 9 forms a solid/liquid phase surface in the flow pipe IA of the separator 1. When the flow path of magnetotactic aquatic bacteria is 1 person and the IB is tilted,
If the flow pipe IC for the settled solid substance is installed within a range of 90 degrees from the vertical direction shown in FIG. 2 to the flow path shown in FIG. 3, the solids will settle well.

In the above embodiments, the target was a tubular separator, but
The present invention is not limited to this.

An example is shown in FIG. The separator 1 shown in FIG. 4 has a rectangular separating section. With such a structure, a large amount of the solution 9 to be separated can be supplied, and the amount of magnetotactic aquatic bacteria recovered can be increased. Moreover, by forming each circulating light into a triangular prism shape and connecting the top to a tubular conduit, it becomes possible to use a pump or the like or to downsize the separation and recovery device.

Furthermore, although the direction of the magnetic field in this embodiment is along the flow pipes IA and IB, it is not limited thereto. For example, the methods shown in FIGS. 5 and 6 may be used. Figure 5 shows
A magnetic pole 2', which shows the movement of magnetotactic aquatic bacteria, is placed above the flow tube IB, and a counter electrode 2 is placed below the flow tube IA. With such a magnet position, it is possible to prevent magnetotactic aquatic bacteria traveling diagonally upward from entering the flow pipe IC. In FIG. 6, a magnetic pole 2' indicating the movement of magnetotactic aquatic bacteria is installed above the flow tubes IA and IB, and a counter electrode 2 is installed below the flow tubes IA and IB.

With this method, since magnetotactic aquatic bacteria always try to move upward, it is possible to prevent them from entering the flow pipe IC.

In the above embodiments, a T-shaped separator was used, but the present invention is not limited to this. Modifications are shown in FIGS. 7 and 9. In FIG. 7, a magnetic field is applied in the vertical direction, the solution to be separated 9 is supplied from the side or diagonally downward, and the flow pipe I
In this system, B is placed at the top and the flow pipe IC is placed at the bottom, so that the direction of sedimentation of the sedimentary solid substance in the separation section is clearly different from the direction of travel of the magnetotactic aquatic bacteria. Figure 8 shows a pipe with a large diameter in the center, a flow pipe IB above it, and a flow pipe I at the bottom.
Insert the flow pipe IA from below into the separator 1 provided with the
Magnets 2 and 2' are installed in the force direction of flow pipes IA and IB. The settling solid substances in the solution to be separated 9 fed into the center of the separator 1 by the flow pipe IA begin to settle immediately after being introduced into the separator 1, and are collected from the flow pipe IC along the sloping bottom. be done. On the other hand, magnetotactic aquatic bacteria rise along the vertically applied magnetic field and are collected from the flow tube IB. According to this method, it is not possible to form a solid/liquid phase in the flow tube IA and to move magnetotactic aquatic bacteria to the liquid phase in advance, but in order to do this, it is necessary to turn the entire body horizontally. good.

Incidentally, although the above embodiments have mainly been described as a one-stage separation and recovery method using one separator, the present invention does not preclude the use of a plurality of separators. If the separation and recovery device shown in FIG. 1 is used, the liquid discharged from the solid matter discharge device 7 will be supplied to the inlet of the separator in the next step.

Furthermore, although the present invention uses two magnets forming opposite poles, one
It is possible to collect magnetotactic aquatic bacteria even with a single magnet. Further, in the above embodiment, the separator 1 has one solids flow pipe IC, but a plurality of pipes may be provided. With this method,
Sedimentable solid substances can be separated satisfactorily. In addition,
The present invention may be used in combination with the above-described embodiments with respect to the structure and installation method of the separator and the method of applying the magnetic field.

〔Effect of the invention〕

As explained above, according to the present invention, by taking advantage of the characteristics of magnetotactic aquatic bacteria, a large throughput and high recovery efficiency can be expected with a simple separation and recovery device. Also, it does not involve stirring.
Since the separation is carried out in a stationary state, it is possible to recover magnetotactic aquatic bacteria without causing functional impairment.

Furthermore, by using a T-shaped separator, it is possible to prevent sedimentation of magnetotactic aquatic bacteria in the separation section, contributing to improvement in recovery efficiency. As shown in Fig. 9, in the separating section (T-shaped section) of separator L, the solids 10 settle along the wall of the conduit near the solution inflow side, but on the opposite wall there is an upward flow. This is because This effect can be similarly expected if the solid matter sedimentation conduit is installed diagonally in front of the magnetotactic aquatic bacteria distribution section, but cannot be expected if it is installed in the opposite direction.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Figs. 2 and 3 are explanatory diagrams of the separator installation method, Fig. 4 is a structural diagram of the separator, and Figs. 5 and 6 are FIGS. 7 and 8 are diagrams showing how to apply a magnetic field, FIGS. 7 and 8 are diagrams showing the separator structure when a magnetic field is applied in the vertical direction, and FIG. 9 is a diagram showing the effects of the present invention. DESCRIPTION OF SYMBOLS 1... Separator, 2, 2'... Magnet, 3... Solid matter collector, 4... Bacteria collector, 5... Solution supply device, 6
... Auxiliary liquid supply device, 7... Solid matter discharge device.

Claims (1)

[Claims] 1. A magnetic field is formed by an electromagnet or a permanent magnet, a separator having three communication ports communicating with each other is located within the magnetic field, and a separator is placed along the lines of magnetic force from the first communication port of the separator. A solution containing aquatic bacteria having the ability to travel along the water and a settleable solid substance other than the aquatic bacteria is supplied, and the settleable solid substance is caused to settle by electric power into a second flow port that is connected downward from the first flow port. . A method for separating and recovering aquatic bacteria, characterized in that the solution containing the aquatic bacteria is taken out from a third flow port. 2. The method for separating and recovering aquatic bacteria according to claim 1, wherein the separator is made of a non-magnetic material. 3. A separator in which the first flow port and the third flow port are straight pipes, characterized in that magnetic poles are located at both ends of the first flow port and the third flow port of the separator. A method for separating and recovering aquatic bacteria according to item 1. 4. Separation of aquatic bacteria according to claim 1, wherein in the separator, one magnetic pole is located below the first flow port and the other magnetic pole is located above the third flow port. Collection method. 5. The aquatic bacteria according to claim 1, wherein in the separator, the first flow port and the third flow port are horizontal or the third flow port is raised higher than the first flow port. Separation and recovery method. 6. The method for separating and recovering aquatic bacteria according to claim 1, wherein the second flow port is communicated with a closed container filled with a solution.