JPH024704A - Method for preventing and eliminating damage of adhesive microorganism by lytic bacteria - Google Patents

Abstract

PURPOSE:To lyse and kill microorganisms adhering to solid surfaces in carrying out heat recovery or exchange utilizing seawater by adding an adequate amount of bacterial parasitic bacteria or administering a sponge containing the bacterial parasitic bacteria cultured and impregnated therein into intake seawater. CONSTITUTION:Fouling microorganisms adhering to solid surfaces in carrying out heat exchange, etc., utilizing seawater, such as various apparatuses in ocean thermal difference power generation systems, littoral electric power stations or combinates, and driving units in ships are prevented and eliminated. In the process, bacterial parasitic bacteria (derovibrio) are added into intake seawater and the above-mentioned microorganisms are subjected to lytic treatment. The treated seawater is subsequently brought into contact with the solid surfaces to lyse newly adhered fouling microorganisms and then partially circulated for use. Alternatively, sponge balls prepared by separately culturing and impregnating the derovibrio thereinto are administered into seawater to lyse the microorganisms. The resultant sponge balls are simultaneously brought into contact with the solid surfaces to also carry out mechanical washing. The derovibrio is readily handled due to high survival ratio and vigorous fecundity thereof.

Description

[Detailed Description of the Invention] (1) Purpose of the Invention [Field of Industrial Application] The present invention is applicable to ocean temperature difference power generation systems, various devices in coastal power plants and industrial complexes, LNG vaporization devices in LNG import terminals, and ships. This invention relates to a method for preventing and erasing adherent microbial contamination on various solid surfaces that come into contact with seawater, such as drive devices that utilize seawater for heat recovery and heat exchange for cooling.

[Prior Art] Biological contamination caused by adherent bacteria, which are fouling microorganisms, is an extremely important problem industrially as it causes a decrease in the efficiency of the heat exchange system. A wide variety of scientific, physical, and mechanical methods have been used to prevent biofouling caused by sessile organisms, but environmental problems and insufficient control effects have been reported. It is.

By the way, conventional methods of this kind to solve the problem of reduced heat transfer in heat exchangers due to biological fouling include antifouling agent sterilization methods, which are expensive and toxic to harmless microorganisms, animals and plants, and lead to environmental destruction.
Other methods include hot water treatment, special paint application, osmotic shock, ultraviolet irradiation, ultrasonic vibration, and mechanical cleaning using sponge balls or brushes, but all of them have drawbacks and cause various problems. I had to carry it.

There are no actual measures to prevent biological fouling that focus on attached bacteria, and currently biological methods that utilize the parasitic relationship of living organisms are being developed.

The premise is that the mechanism of biofouling formation is [■ Matter in the seawater adheres to the heat transfer surface that comes into contact with seawater, forming a film. ■Bacteria adhere to the film. ■Adhering bacteria multiply, produce and secrete polysaccharides, and form microbial stains. ■Adherent bacteria, other types of microorganisms that feed on their secretions, and larvae of large adhesion substances adhere to the surface and multiply, forming macrobiological stains. ”
The aim is to biologically treat the microbiological fouling stage before the macrobiological fouling.

That is, in order to eliminate the disadvantages of the conventional means,
A biofouling prevention method described in No. 159596 was invented.

[Problems to be solved by the invention] In the invention, the virus used to prevent microorganism stains is a bacterial virus, also called a bacterium phage, which has a simple structure consisting only of nucleic acids (genes) and proteins. Since they cannot reproduce, they require a bacterial host.

However, the bacterial phages used are several hundred times smaller than bacteria and have a simple structure, so their survival conditions are harsh and they easily react to the environment.They are difficult to isolate, culture, and propagate, and require highly skilled techniques. It is difficult to use on an industrial scale because it is difficult to handle.

The present invention provides a method for preventing and eliminating adherent microbial fouling using parasitic bacteria, which requires highly skilled techniques, can be isolated, cultured, and propagated, is easy to handle, and can be used on an industrial scale. This is what I am trying to do.

(2) Structure of the Invention [Means for Solving the Problems] The method for preventing and erasing adherent microbial fouling of the present invention eliminates fouling microorganisms floating in the taken seawater by bringing seawater into contact with a solid surface. severe bacteriolysis, recycling and reuse of a portion of the seawater that has come into contact with the solid surface, and subsequent lysis treatment of the fouling microbial layer that has already adhered to the solid surface after contacting it. In this case, an appropriate amount of parasitic bacteria is added to the taken seawater, and a sponge cultured and impregnated with parasitic bacteria is administered to lyse and kill the fouling microorganisms in the seawater and on the attached seawater.

[Effect] The bacterial parasitic bacteria (hereinafter referred to as Zorovibrio) used in the method of the present invention are higher microorganisms that are hundreds of times larger than bacterial phages and have a high survival rate and are robust, so they do not require skilled techniques. It can be isolated, cultured, and propagated simply and easily, and industrial mass production is possible.

Here Zorobibrio and Bacteria Phage (below) 7
- I will explain the survival resistance test against suspension in seawater.

Among these biological methods, in order to compare the method using Zorovibrio (method of the present invention) and the method using phage (conventional method), the survival resistance after addition to intake seawater was compared.

Purpose: To compare the survival times of Zorovibrio and 77-di when suspended in seawater.

Method 1: Delovibrio, phages, and adherent bacteria are isolated from the Tokyo trench seawater by a general culture method for lytic microorganisms (hereinafter referred to as the multilayer agar culture method), and Zorovibrio is placed in sterilized seawater.

Phage 0, 0.5.1, 2, 4, 8.12.1 respectively
After suspending for 6 minutes, its survival was confirmed by multilayer agar culture. The test was conducted three times in the same manner.

Here, the processes at each stage of the multilayer agar culture method will be explained with reference to FIGS. 1(a) to (d).

■The process of creating the nutrient-added seawater agar sublayer medium (2) in the container (1).
Host) (3) addition process (see Figure 1 (b))> ■ Addition process of phages and Zorovibrio (4) <
See Figure 1 (C)> ■ Addition process of seawater soft agar upper layer medium (5) <Figure 1 (
See d) ■Cultivation process for 24 hours (phage) and 48 hours (Zorovibrio) under a temperature condition of 20° ± 1°C ■After culturing, count the lytic plaques, and calculate p, fU, (
It was carried out through ■~■ process steps that were more than the old school process of lytic science and mathematics.

Results: The results shown in the table below were obtained. However, the numerical values in the table are expressed as p, f, u/Im.

As mentioned above, Zorovibrio can be submerged in sterile seawater for 2 minutes (
The results showed that it survived even when suspended (up to 12 minutes), and it was presumed that it survived within the residence time of the water intake system (5 to 7 minutes) even when added to the water intake system.

On the other hand, Fuji 7-ji could not be cultured in this test. The isolation and culture method used was a general method for handling lytic microorganisms, but the isolation and maintenance culture of phages was more difficult than that of Zorovibrio, and it was surmised that there was room for improvement.

In this way, the test results show that Zorovibrio is easier to culture than phages, and maintenance and other management are easier than phages for the long-term, large-scale cultivation required when Zorovibrio is used as a control agent for attached bacteria. It is thought that.

Next, the lysis process for Zorovibrio adherent fouling bacteria will be explained.

■ First, the attachment process of Zorovibrio to bacteria ■ Host ta
Invasion process into the rra ■Protoplasm utilization process within the host cell ■Division and multiplication process of Zorovibrio within the host cell ■Release process of Zorovibrio by swelling and rupture of the host cell Step by step through a life cycle consisting of the above processes Sterilizes adherent fouling bacteria.

As described above, according to the method of the present invention, a medicinal efficacy equivalent to that of a phage is exhibited.

[Example 1] In the first example of the method of the present invention, Zorovibrio is cultured and stored in a tank that has been separately cultured and stored using a known culture and propagation method similar to, for example, phages, into taken seawater by adjusting the supply flow rate of the seawater. It is added in an appropriate amount to treat the fouling bacteria floating in the seawater (a process in which the parasitic bacteria infect the host attached fouling microorganisms), and the treated seawater is then transferred to a heat exchanger with a solid surface. It comes into contact with the surface and lyses newly attached fouling microorganisms.

[Example 2] In the second example of the method of the present invention, Zorovibrio was added to the seawater taken from a tank that had been separately cultured and stored in the same way as in the first example. After adding an appropriate amount of lytic bacteria to the fouling bacteria floating in the seawater and performing bacteriolytic treatment, the treated seawater is diverted and a part of it is circulated and mixed with newly taken seawater for circulation. Use it.

[Example 3] In the third example of the method of the present invention, Zorovibrio is added to the seawater taken in an appropriate amount from a tank in which it has been separately cultured and stored in advance, taking into consideration the supply flow rate of the seawater. After the floating fouling bacteria are lysed, the treated seawater is subsequently brought into contact with the solid surface of the heat exchanger, and the already attached layer of fouling bamboo bacteria is subsequently lysed to eliminate the fouling bacteria. The layer is lysed and removed.

[Example 4] In the fourth example of the method of the present invention, sponge balls containing a separate culture of Zorovibrio are administered into seawater in a number commensurate with the supply flow rate, and floating fouling bacteria are removed during the flow. After the bacteriolytic treatment, the sponge balls are brought into contact with the heat exchanger surface, which is a solid surface, and if a fouling bacterial film has already adhered to it, the said fouling bacterial film is scraped off with the sponge ball at the same time as the mechanical cleaning. The sponge ball is lysed and eliminated by Zorovibrio released from the sponge ball, and the used sponge ball is collected and reused.

Note that the sponge is not limited to the ball shape as in the embodiment. Further, the solid surface is not limited to the heat exchanger surface shown in the examples.

(3) Effects of the invention Thus, compared to the conventional method using bacteriophages, the method of the present invention extracts and uses Zorobibrio, which has a high survival rate, is robust, and has high reproductive ability, so it does not require a high level of skill. As a result, control operations for separation, cultivation, and proliferation become simple and easy, dramatically improving ease of handling, and providing excellent effects such as making it possible to use the product on an industrial scale.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are step-by-step process illustrations of the multilayer agar culture method. Figure 1 (α) Figure 1 (b) Figure 1 (C) 1... Container 2... Nutrient-added seawater agar sublayer medium 3... Adhesive fouling microorganisms 4... Phages and Zorovibrio 5. ...Seawater soft agar upper layer Figure 1 (d) Procedural amendment (method) September 30, 1985 Commissioner of the Patent Office Ko 1) Moon Takeshi 1, Indication of case Patent Application No. 154959 of 1988 2, Title of the invention Method for preventing and erasing adherent microbial contamination caused by lytic bacteria 3, Relationship with the case of the person making the correction Patent applicant: 6-15-1 Ginza, Chuo-ku, Tokyo Electric Power Development Co., Ltd. Nihonbashi, Chuo-ku, Tokyo 3-1-15 Tokyo Kueri Co., Ltd. Address: 105 Address 4, 1-20-11, NishillTl, Minato-ku, Tokyo 7. Contents of amendment (1) Page 13 of the specification, line 12 “No. 1 (a) to (b)...'' is corrected to [Figure 1 (a) to (d) are...''). Shipping date: September 27, 1988)

Claims (1)

[Scope of Claims] 1. To prevent microbial fouling by adding microorganisms to the intake water and performing bacteriolytic treatment of the fouling microorganisms floating in the seawater taken in, the lytic treatment of the fouling microorganisms involves Method 2 for preventing adherent microbial fouling caused by lytic bacteria by adding parasitic bacteria. Method 3 for preventing adherent microbial fouling by lytic bacteria, which involves adding parasitic bacteria as the lytic microorganisms to the fouling microorganisms by circulating and using a portion of the used seawater that has been brought into contact with the water. Targeting adherent fouling microorganisms that adhere to solid surfaces in seawater When microorganisms are added to the intake water and the microbial fouling is prevented and eliminated through lysis treatment, parasitic bacteria are removed as the lysis treatment of the fouling microorganisms. Method 4 for preventing and eliminating adherent microbial fouling caused by lytic bacteria by adding lytic microorganisms to contacting adherent fouling microorganisms attached to solid surfaces in taken seawater, Prevention of adherent microbial fouling by lytic bacteria by recycling a part of the used seawater that has been brought into contact with the lytic microorganisms and adding parasitic bacteria as the lytic microorganisms of the fouling microorganisms.・Elimination method 5: Sponge balls cultured and impregnated with lytic microorganisms are thrown into seawater, and the fouling microorganisms floating in the water are lysed and the fouling adheres to the solid surface that the sponge balls come into contact with. In this method of preventing and erasing microbial contamination, the method involves lysing the lytic microorganisms and collecting the used sponge balls. Prevention/erasing method