JP7095871B2 - Microorganisms that produce group III-V compound semiconductors - Google Patents

Description

NPMD NITE P-02755

The present disclosure relates to a microorganism that produces a group III-V compound semiconductor, a screening method thereof, and a method for producing a group III-V compound semiconductor using the same.

The production of organic compounds using microorganisms has long been carried out in the form of fermentation. In recent years, studies have also been conducted on the production of biopharmaceuticals. Furthermore, a phenomenon called biomineralization, in which microorganisms produce various inorganic compounds, is drawing attention.
By using biomineralization, microorganisms may be used for the production of inorganic compounds as well as organic compounds.

For example, a method for producing metallic selenium using a microorganism of the genus Thauera has been studied (see, for example, Patent Document 1).

It is also being studied to produce II-VI group semiconductors such as selenium-cadmium using microorganisms of the genus Acetonema (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 9-248595 Japanese Unexamined Patent Publication No. 2005-341817

If a group III-V compound semiconductor having extremely high utility value as a semiconductor can be produced by microorganisms, its usefulness is immeasurable.

An object of the present disclosure is to enable microorganisms to produce group III-V compound semiconductors.

One aspect of the microorganism disclosed in the present disclosure is a microorganism belonging to the genus Marichromatium, which produces a group III-V compound semiconductor by culturing using a medium containing a group III element and arsenic.

The microorganisms disclosed in this disclosure were assigned to NITE P-02755 on July 24, 2018 by the National Institute of Technology and Evaluation, Patent Microorganisms Depositary Center (address: 2-5-8 Kazusakamatari, Kisarazu City, Chiba Prefecture). It can be the deposited Marichromatium sp. IN3.

The microorganisms of the present disclosure may form a flora with other microorganisms.

One aspect of the method for obtaining a Marichromatium genus microorganism of the present disclosure is a primary screening in which a plurality of media containing one kind of Group III element and not containing arsenic and a medium containing arsenic and not containing Group III elements are used for screening. And the secondary screening in which the primary screening strain selected by the primary screening is screened using a medium containing one or more group III elements and arsenic.

One aspect of the method for producing a group III-V compound semiconductor of the present disclosure uses a microorganism belonging to the genus Marichromatium obtained by the method of the present disclosure.

In one aspect of the method for producing a Group III-V compound semiconductor of the present disclosure, the Marichromatium genus microorganism was introduced on July 24, 2018 by the National Institute of Technology and Evaluation, Patent Microorganism Depositary Center (address: Kisarazu City, Chiba Prefecture). It can be Marichromatium sp. IN3 deposited under Kazusakamatari 2-5-8) as the accession number NITE P-02755.

In one aspect of the method for producing a group III-V compound semiconductor of the present disclosure, a microorganism belonging to the genus Marichromatium may form a flora together with other microorganisms.

According to the Marichromatium genus microorganism of the present disclosure, a group III-V compound semiconductor can be produced by culturing.

It is an electron micrograph which shows the structure formed in the microorganism body in Example 1. FIG. It is the result of elemental analysis of the structure shown in FIG. It is an electron micrograph showing a structure taken out from the body. It is a magnified image of FIG. 3A. It is a magnified image of FIG. 3B. It is the result of elemental analysis of the structure taken out from the body.

The microorganism in the present disclosure is a microorganism containing the genus Marichromatium, which produces a group III-V compound semiconductor in the body by culturing using a medium containing a group III element and arsenic. The genus Marichromatium is a type of purple photosynthetic bacterium, which is distributed in seawater and the like, and can be collected from it.

At least among the microorganisms belonging to the genus Marichromatium, on July 24, 2018, the National Institute of Technology and Evaluation Patent Microorganisms Deposit Center (NPMD: Address: 2-5-8 Kazusakamatari, Kisarazu City, Chiba Prefecture, Japan 292-0818, Marichromatium sp. IN-3 (accession number NITE P-02755) deposited in Room 120) has the ability to produce Group III-V compound semiconductors in the body.

Microorganisms containing the genus Marichromatium, which have the ability to produce III-V compound semiconductors in the body, can be obtained as follows.

First, microorganisms are inoculated into each of a plurality of media containing only one type of Group III element and containing no arsenic and a medium containing arsenic and not containing Group III elements, and primary screening is performed to select a primary screening strain. do. Next, the obtained primary screening strain is inoculated into a medium containing one or more group III elements and arsenic, and secondary screening is performed.

As the microorganism for the primary screening, a microorganism collected from seawater or the like by a usual method can be used. Culturing of microorganisms belonging to the genus Marichromatium can be carried out under static anaerobic conditions using a photosynthetic bacterium minimal medium (RCVBN medium) as a basal medium. The microorganism to be screened can be in the state of a microbiota (microbiota group) containing a plurality of types of microorganisms.

The group III element in the primary screening depends on the target group III-V compound semiconductor, and can be, for example, indium (In), gallium (Ga), and aluminum (Al). Group III elements can be added, for example, as an aqueous solution of indium chloride tetrahydrate, an aqueous solution of gallium nitrate (III) n hydrate, or an aqueous solution of aluminum chloride (III) hexahydrate. Arsenic can be added, for example, as an aqueous solution of potassium arsenic. The concentration of the Group III element added to the medium at the time of the primary screening can be about 100 μM to 1 mM, and the concentration of arsenic can be about 100 μM to 1 mM.

As the group III element added in the secondary screening, one or more can be selected from the group III elements used in the primary screening according to the target group III-V compound semiconductor. For example, if the target group III-V compound semiconductor is gallium-arsenide (GaAs), gallium may be used, and if it is indium-gallium-arsenide (InGaAs), indium and gallium may be used. Often, indium-aluminum-gallium-arsenide (InAlGaAs) may be indium, aluminum and gallium.

The concentration of each Group III element added to the medium at the time of the secondary screening can be about 100 μM to 1 mM, and the concentration of arsenic can be about 100 μM to 1 mM.

The determination of the secondary screening can be made based on whether or not the III-V compound semiconductor is finally produced in the body of the microorganism. For example, first confirm whether Group III elements and arsenic have been incorporated into the body of a living microorganism by inductively coupled plasma (ICP) emission spectroscopic analysis, and then use a transmission electron microscope to confirm whether III-V has been incorporated into the body. It suffices to confirm whether or not the group compound semiconductor is produced.

The Marichromatium genus microorganism that produces a III-V compound semiconductor in the body thus obtained may form a flora (microbiota group) together with other microorganisms. It is not necessary for the Marichromatium genus microorganism to be isolated in the production of the III-V compound semiconductor, and the III-V compound semiconductor can be produced in the body in the state of the flora containing other microorganisms. For example, in the case of Marichromatium sp. IN-3, Pseudomonas sp., Alkaliphilus transvaalensis, Serratia sp., And Rikenellaceae Blvii 28 may be contained in the flora in addition to Marichromatium sp. However, not all of these microorganisms may be contained in the flora, and microorganisms other than these microorganisms may be contained in the flora. The microorganisms contained in the flora can be identified by sequence analysis of 16S rRNA.

By culturing the obtained bacterial flora containing the Marichromatium genus microorganism or the Marichromatium genus microorganism in a medium containing a group III element and arsenic, a group III-V compound semiconductor such as InGaAs can be produced in the body. At least a part of the III-V compound semiconductor is in a crystalline state, and the rest is in an amorphous state. The concentration of the group III element added to the medium when producing the III-V compound semiconductor can be about 100 μM to 1 mM, and the concentration of arsenic can be about 100 μM to 1 mM. The culturing time is preferably 144 hours or more, more preferably 240 hours or more, from the viewpoint of promoting crystal growth. The longer the culture time, the more crystals grow, but 3 months or less is preferable in consideration of maintaining the growth conditions of microorganisms.

The III-V compound semiconductor produced in the body of a microorganism belonging to the genus Marichromatium can be recovered as follows. First, the cells are collected by centrifugation, suspended in a buffer solution (10 mM, pH 8.0) such as Tris-HCl, lysozyme (final concentration 200 μg / mL) is added, and left at 37 ° C. for 30 minutes, and then 1 % SDS is added 1/10 vol. And left in a hot water bath at 65 ° C. for 15 minutes to disrupt the cells. Centrifuge the cell disruption solution to recover the Group III-V compound semiconductor as a precipitate, wash with sterilized ultrapure water, and repeat until the washing solution becomes transparent. The washed III-V compound semiconductor may be dried and used.

The recovered III-V compound semiconductor can be developed as a thin film on a glass substrate or the like and used for a solar cell or the like.

The Marichromatium microorganisms that produce group III-V compound semiconductors in the present disclosure are used for environmental purification because they take up group III elements and arsenic in the environment and convert them into useful group III-V compound semiconductors. You can also.

A microorganism belonging to the genus Marichromatium that produces a group III-V compound semiconductor in the body of the present disclosure and a method for producing a group III-V compound semiconductor using the same will be described in more detail with reference to examples.

<Collection of Marichromatium microorganisms>
Microorganisms collected from gravel from Kojima, Imabari City, Ehime Prefecture were used for screening.

<Screening method>
First, microorganisms were cultured in RCVBN medium containing 1 mM In ³⁺ or 1 mM Ga ³⁺ to obtain a primary screening strain. The obtained primary screening strain was cultured in RCVBN medium containing 1 mM In ^{3+, 1 mM Ga 3+ and} 1 mM potassium arsenate to obtain Marichromatium sp. IN-3.

<Method of identifying microbial community>
Marichromatium sp. IN-3 forms a flora, and the coexisting microorganisms were confirmed to be Pseudomonas sp., Alkaliphilus transvaalensis, Serratia sp., And Rikenella ceae Blvii 28 by sequence analysis of 16S rRNA.

<Culture method>
The flora containing Marichromatium sp. IN-3 was cultured in RCVBN medium containing In, Ga and As under fluorescent light irradiation at room temperature (25 to 27 ° C.) for 7 days. In, Ga and As were added as an aqueous solution of indium chloride tetrahydrate, an aqueous solution of gallium (III) n hydrate and an aqueous solution of potassium arsenate, respectively. The concentrations of In, Ga and As in the culture broth were 1 mM each.

<Evaluation method>
The cultured microorganisms were confirmed by a transmission electron microscope (JEM-2010, manufactured by JEOL Ltd.) to see if a structure having a high electron density was formed in the body. Elemental analysis of the structures inside the body was performed by energy dispersive X-ray spectroscopy (JED-2300, manufactured by JEOL Ltd.). In addition, it was confirmed by a thin film structure evaluation X-ray diffractometer (XRD) (ATX-E, manufactured by Rigaku) that a crystal structure was present.

(Example 1)
FIG. 1 shows an electron microscope image of Marichromatium sp. IN-3 after culturing for 7 days. A structure with high electron density is formed in the body. FIG. 2 shows the results of elemental analysis of the structures in the body. It is clear that In, Ga and As are contained. The presence of phosphorus and oxygen was also confirmed. 3A to 3C show the results of observing the structure taken out from the body at a higher magnification. From the XRD measurement results, it was confirmed that the structure was an amorphous mineral, and a part of it formed a crystal structure. In addition, In, Ga, As and the like were also found in the elemental analysis of the structure taken out as shown in FIG. Compared with FIG. 2, the ratio of In, Ga and As to carbon (C) is very high, and In, Ga and As are not only taken up in the body of the microorganism but also a structure in the body. It is clear that it forms.

The Marichromatium genus microorganism of the present disclosure produces a group III-V compound semiconductor in the body and is useful in the production of inorganic compounds using biomineralization and the like.

Claims (6)

Marichromatium sp deposited on July 24, 2018 at the National Institute of Technology and Evaluation, Patent Microorganisms Depositary Center (address: 2-5-8 Kazusakamatari, Kisarazu City, Chiba Prefecture) under the accession number NITE P-02755. . IN3 , Marichromatium genus microorganism. The Marichromatium genus microorganism according to claim 1 , wherein the Marichromatium genus microorganism forms a flora together with other microorganisms. Primary screening and screening using a plurality of media containing one kind of Group III element and not containing arsenic and a medium containing arsenic and not containing Group III elements, respectively.
The genus Marichromatium that produces group III-V compound semiconductors in the body, including a secondary screening in which the primary screening strain selected by the primary screening is screened using a medium containing one or more group III elements and arsenic. How to get microorganisms. A method for producing a group III-V compound semiconductor using a microorganism belonging to the genus Marichromatium obtained by the method according to claim 3 . The Marichromatium genus microorganism was sent to the National Institute of Technology and Evaluation, Patent Microorganisms Depositary Center (address: 2-5-8 Kazusakamatari, Kisarazu City, Chiba Prefecture) on July 24, 2018 as the accession number NITE P-02755. The method for producing a Group III-V compound semiconductor according to claim 4 , which is the deposited Marichromatium sp. IN3. The method for producing a group III-V compound semiconductor according to claim 4 or 5 , wherein the microorganism belonging to the genus Marichromatium forms a flora together with other microorganisms.

Images