JP2003274930A - Growth control of microorganism by light irradiation and method for cultivation of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for effective cultivation of a microorganism by controlling growth of the microorganism under irradiation with light. <P>SOLUTION: The method characteristically promotes the growth of the microorganism by irradiating the microorganism with light, especially with the light from orange light to far-red light, and suppresses the growth of the microorganism and promotes sporulation by irradiating the microorganism with blue light. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the growth of microorganisms, especially filamentous fungi, by irradiation with light to improve the culture technology of the fungi.

[0002]

Regarding the influence of light on the growth of microorganisms, it is well known that light in the ultraviolet region significantly inhibits the growth of microorganisms. It has also been clarified that microorganisms such as photosynthetic bacteria require red light of around 660 nm and blue light of around 430 nm for photosynthesis and growth. However, little is known so far about the effect of light in the visible region other than the ultraviolet region on the growth of microorganisms other than photosynthetic bacteria, and therefore, the culture of microorganisms other than photosynthetic bacteria is generally performed in the dark. is the current situation.

On the other hand, in culturing microorganisms, it is important to establish a technique for artificially cultivating beneficial microorganisms such as mycorrhizal fungi, which is one of filamentous fungi. Mycorrhizal fungi are one of the symbiotic microorganisms that infect plants and help the plants absorb nutrients and water, and are the symbiotic microorganisms that are currently receiving a great deal of attention in order to build a sustainable cultivation system with low input from now Because. This fungus is an absolute symbiotic bacterium, and it has been said that pure culture has been impossible until now. One of the present inventors, Ishii et al., Cultivate VA mycorrhizal fungi artificially without using live plant roots. We succeeded in developing the technology ahead of the world (Japanese Patent Laid-Open No. 8-191685). However. This culturing technique (light environment conditions were dark) had the problem that hyphae grew slowly and it took time for sporulation to occur. In addition, in the case of this bacterium, it has been reported that spore formation is inhibited when light enters the container in culture using hairy roots (Tatsuo Hayashi, Hiroshi Adachi, Hidehiko Ishimaru. 199).
3. Inheritance 47 (7): 66-71).

[0004]

SUMMARY OF THE INVENTION The inventors of the present invention have
As a result of researching how light quality influences the growth of microorganisms using various light emitting diodes etc., irradiation from radiant light to far red light promotes growth of microorganisms, while irradiation with blue light Found that the growth of microorganisms was suppressed and sporulation was promoted. Microorganisms tested in this study were filamentous fungi such as mycorrhizal fungi (VA mycorrhizal fungi, Ganoderma lucidum and Matsutake fungi), blue mold (KI01), rapeseed anthracnose, and anthracnose anthracnose, and Bacillus subtilis.
subtilis IAM12021), Staphylococcus aureus
Bacteria such as 3062).

Therefore, an object of the present invention is to provide a method for improving the culture technique by controlling the growth of microorganisms, particularly filamentous fungi, by irradiating with light of far colored light to far red light or blue light.

[0006]

Means for Solving the Problems As a result of intensive research to solve the above problems, the present inventors have shown that the growth of microorganisms is promoted by culturing under irradiation with light of a radiant color light to a far red light. In addition, it was found that the growth of microorganisms was suppressed and the sporulation was promoted by the culture under the irradiation of light with blue light, and the present invention was completed based on these findings.
That is, the present invention provides a technique for artificially culturing microorganisms by light irradiation that causes proliferation or suppression of the microorganisms.

[0007]

DETAILED DESCRIPTION OF THE INVENTION

EXAMPLES Next, the present invention will be described in detail with reference to Examples.

Example 1 [Effects of culturing in darkness and in white light and red light of fluorescent lamp on VA mycorrhizal mycelium growth] Basic medium (Hidenori Muramatsu, Takaaki Ishii, Isamu Matsumoto, Kazuomi Kadoya) 1995. Journal of Horticultural Science 64 Supplement 2: 106-10
Glucospora margarita (Gigaspor) was surface-sterilized after placing 10 ml of a medium in which glucose was replaced with mannitol of 50 ppm in a petri dish (diameter 70 mm) and sterilized by an autoclave (121 ° C., 15 minutes).
a margarita) spores were placed on the medium. After that, the cells were cultured in the dark at 27 ° C., under white light of fluorescent lamp (light intensity: 30 μE · m-2s−1) and under red light (light intensity: 10 μE · m-2s−1) for 1 week, and then CCD
Image processing method using a stereomicroscope equipped with a camera and a personal computer (Ishii et al. 1996. Journal of the Horticultural Society 65 (3):
525-529), the growth of hyphae from spores was measured. The wavelength of red light is 660n as shown in FIG.
The peak is m. As a result, no significant difference was observed in the mycelium length of 1 to 2 mm under the dark light and the white light of the fluorescent lamp, but under the red light, the growth was 4 to 9 times as remarkable as that under the dark or white light. A promoting effect was observed (Fig. 2).

Example 2 [Effect of light irradiation by light emitting diodes (LEDs) of various wavelengths on mycorrhizal mycelial growth] Surface-sterilized Gigaspora margarita (Giga)
spores of spora margarita)
Bahiagrass 25% MeOH eluate (0.1 g DW / 10 ml) was added to the basal medium used in step (diameter 70
mm petri dish), under darkness at 27 ° C., 450 nm, 510 nm, 590 nm, 612 nm,
LE with peak wavelengths of 660 nm and 730 nm
10 under D (Fig. 3, light intensity: 10 µE · m-2s-1)
After culturing for a day, the mycelium length was measured by the same method as in Experiment 1. In addition, at 660 nm, the investigation was performed even under the light intensity of 40 μE · m−2s−1. In addition, agar containing mycelium (diameter: 7
mm) was cut out and inoculated in MMN medium.
Then, the cells were cultured under red light, blue light and darkness at 27 ° C., and the mycelial growth in each treatment group was compared and investigated. As a result, in Experiment 2 using the LED, almost the same results were obtained.
Light irradiation in the red region of 2 to 730 nm showed a prominent mycelial growth promoting effect that was 3 to 5 times that in the case of darkness.
Also, the influence of the difference in light intensity is 40 μE · m-2s-1.
No difference was observed. 510 nm and 59
No significant difference was observed between 0 nm and darkness.
On the other hand, mycelial growth was significantly suppressed by irradiation in the blue region near 450 nm (FIG. 4). Almost the same results were obtained with G. matsutake and Matsutake, and hyphal growth was promoted under irradiation with red light and was inhibited under irradiation with blue light, as compared with under dark conditions (Tables 1 and 2).

Example 3 [Effect of light irradiation by blue light LED (BL) on mycorrhizal mycelial growth] The effect of blue light was investigated in more detail. That is, the surface was sterilized in the same manner as in Example 1 (Gigas Margarita).
Spores of Pora margarita) were placed on the medium used in Example 2 (using a petri dish having a diameter of 70 mm) and precultured for 2 weeks under red light at 27 ° C. After that, 6 treatment sections were provided: dark, after dark irradiation with light of 450 nm (blue light LED) for 0.25, 0.5, 1, 3 hours (h), and further with continuous BL light irradiation. In addition,
The light intensity of blue light was 50 μE · m-2s−1. After 0, 1, 3 and 6 days of treatment, hyphal elongation was measured in the same manner as in Experiment 1. As a result, no significant difference was observed in the dark section after irradiating the blue light of 0.25 h, 0.5 h and 1 h, compared with the continuous dark section, but the dark section and the continuous blue light after irradiation of the blue light of 3 h were observed. A significant growth inhibitory effect was observed in the irradiated area (Fig. 5). In addition, FIG. 6 is a micrograph showing mycelial growth before dark light treatment and after 6 days of blue light treatment in a dark section and a blue light irradiation section for 3 hours.

Example 4 [Red light and blue light LEDs (B
L) Effect of light irradiation on the growth of blue mold, rapeseed anthracnose and urinum anthracnose] PDA (potato dextrose agar) pre-cultured with these filamentous fungi
The hyphae were taken from the medium and again planted in sterile PDA medium. Then, the cells were cultured under red light, blue light and darkness at 27 ° C., and the mycelial growth and sporulation state in each treatment group were comparatively investigated. The light intensity of the red light and blue light LEDs was set to 30 μE · m-2s−1. As a result, as in the case of mycorrhizal fungi, any filamentous fungus, compared to under dark,
Mycelial growth was promoted under irradiation with red light, while it was inhibited under irradiation with blue light (Table 3, FIG. 7 and FIG. 8). Also,
In these filamentous fungi, it was observed that many spores were formed in the petri dish in the blue light irradiation section.

Example 5 [Light irradiation by a blue light LED (BL) was applied to Bacillus subtilis I.
AM12021) and Staphylococcus aureus (Taph)
Effect on Growth of Ylococcus aureus 3062)] These bacteria were taken from a pre-cultured peptone agar medium and again planted in a sterile peptone medium. Then, the cells were cultured in blue light at 27 ° C. and in the dark, and the effect of blue light irradiation on the bacterial growth inhibition was investigated. The light intensity of the blue LED is 30 μE
-It was set to m-2s-1. As a result, it was observed that bacterial growth was slightly suppressed under blue light irradiation as compared with under dark conditions (FIGS. 9 and 10).

[0013]

As described above, according to the present invention, it is recognized that the light quality significantly affects the growth of microorganisms, especially filamentous fungi. Therefore, the present invention is characterized by promoting the growth of microorganisms by light irradiation in the wavelength range from radiant light to far-red light, and suppressing the growth of microorganisms by light irradiation in the blue light wavelength range and promoting sporulation. The present invention is useful for providing a growth control technology for microorganisms and a culture method thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing a wavelength spectrum of a red fluorescent lamp used in Example 1.

FIG. 2 is a diagram showing mycelial growth of VA mycorrhizal fungi in the dark and white light and red light sections by a fluorescent lamp examined in Example 1.

FIG. 3 shows all LEs used in Example 2.
It is a figure which shows the wavelength spectrum of D.

FIG. 4 shows the darkness examined in Example 2 as well as 450 nm, 510 nm, 590 nm, 612 nm, 6
It is a figure which shows the mycelial growth of VA mycorrhizal fungus in the LED light irradiation area of wavelengths of 60 nm and 730 nm.

FIG. 5 shows darkness after 6 days of treatment examined in Example 3, darkness after blue light (BL) irradiation for 0.25, 0.5, 1, and 3 hours, and continuous BL light irradiation. It is a figure which shows the mycelial growth of the mycorrhizal fungus in a ward.

FIG. 6 shows blue light (B
L) Micrographs showing mycelial growth of mycorrhizal fungi before and 6 days after BL treatment in the dark section and in the BL light irradiation section for 3 hours.

FIG. 7 is a diagram showing the growth of rapeseed anthracnose bacterium in the dark and red light and blue light irradiation sections examined in Example 4.

FIG. 8 is a diagram showing the growth of B. anthracis bacteria in the dark and red light and blue light irradiation sections examined in Example 4.

FIG. 9 is a view showing Bacillus subtilis in the blue light irradiation section examined in Example 5.
It is a photograph showing the growth of IAM12021).

FIG. 10 is a diagram showing Staphylococcus aureus in the blue light irradiation area examined in Example 5.
It is a photograph showing the growth of ccus aureus 3062).

FIG. 11 is a table showing the growth of Drosophila melanogaster in the dark and red light and blue light irradiation groups examined in Example 2.

FIG. 12 is a table showing the growth of Pleurotus matsutake in the dark, red light, and blue light irradiation groups examined in Example 2.

FIG. 13 is a table showing the growth of blue mold in the dark and red light and blue light irradiation sections examined in Example 4.

[Explanation of symbols]

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4B065 AA58X BA30 BB01 BB06                       BC32 BC47 BC48 BC50 CA60

Claims (4)

[Claims] 1. A growth control technique for microorganisms, characterized in that the growth of microorganisms is promoted by irradiating it with light of substantially colored light to far-red light. In this patent application,
The roughly colored light to far-red light is light in the light wavelength region of approximately 600 nm (nanometer) to 800 nm. 2. A technique for controlling the growth of microorganisms, wherein the growth of microorganisms is suppressed and sporulation is promoted by irradiating with blue light. In this patent application, blue light is light in the light wavelength region of approximately 400 nm to 490 nm. 3. A method for culturing a microorganism by irradiating the light according to claim 1 or 2 with light being changed alternately or in a growth stage. 4. A microorganism in which the effect of light irradiation is often seen in claims 1 and 2 is particularly a filamentous fungus, and a method for controlling the growth of this microorganism to improve the culture technique.