JP-7855177-B2 - Method for recovering heavy metal ions, structure for recovering heavy metal ions, and method for accumulating microorganisms

JP7855177B2JP 7855177 B2JP7855177 B2JP 7855177B2JP-7855177-B2

Inventors

濱村奈津子
鹿島裕之

Assignees

国立大学法人九州大学
国立研究開発法人海洋研究開発機構

Dates

Publication Date: 20260508
Application Date: 20220307

Claims (11)

A method for recovering heavy metal ions from treated water containing heavy metal ions and inhabited by microorganisms capable of metabolizing heavy metals, The process includes placing a conductor in the water to be treated, and supplying electrons to the conductor to form a precipitate on which the microorganisms are accumulated, and concentrating the heavy metal ions in the precipitate . The heavy metal ion is an ion of one or more metals selected from the group consisting of iron, manganese, arsenic, and antimony. The method wherein the microorganism is a microorganism belonging to the class Gamma-Proteobacteria that has a 16S rRNA gene consisting of (a1), (b1), (a2), (b2), (aa), or (bb) as described below; (a1) A polynucleotide consisting of the sequence described in Sequence ID No. 1, (a2) A polynucleotide consisting of the sequence described in Sequence ID No. 3, (b1) A polynucleotide consisting of the sequence described in Sequence ID No. 2, (b2) A polynucleotide consisting of the sequence described in Sequence ID No. 4, (aa) A polynucleotide consisting of a sequence having 98.0% or more identity with the base sequence of Sequence ID No. 1 or 3, (bb) A polynucleotide consisting of a sequence having 98.0% or more identity with the base sequence of Sequence ID No. 2 or 4.
The method according to claim 1, wherein the water to be treated is mine wastewater, factory wastewater, environmental water, or groundwater.
The method according to claim 1 or 2 , wherein the microorganism is a rod-shaped bacilli having extracellular fibers.
The method according to any one of claims 1 to 3 , wherein the precipitate is a porous crystal containing calcium carbonate.
A water treatment method for removing heavy metal ions from water containing heavy metal ions, comprising recovering heavy metal ions by the method described in any one of claims 1 to 4 .
A structure for recovering heavy metal ions from treated water containing heavy metal ions, The material comprises a conductor and a precipitate that covers at least a portion of the surface of the conductor, The precipitate contains microorganisms having heavy metal metabolism capabilities, The heavy metal ion is an ion of one or more metals selected from the group consisting of iron, manganese, arsenic, and antimony. The structure is a microorganism belonging to the class Gamma-Proteobacteria, having a 16S rRNA gene consisting of (a1), (b1), (a2), (b2), (aa), or (bb) as described below; (a1) A polynucleotide consisting of the sequence described in Sequence ID No. 1, (a2) A polynucleotide consisting of the sequence described in Sequence ID No. 3, (b1) A polynucleotide consisting of the sequence described in Sequence ID No. 2, (b2) A polynucleotide consisting of the sequence described in Sequence ID No. 4, (aa) A polynucleotide consisting of a sequence having 98.0% or more identity with the base sequence of Sequence ID No. 1 or 3, (bb) A polynucleotide consisting of a sequence having 98.0% or more identity with the base sequence of Sequence ID No. 2 or 4.
The structure according to claim 6 , wherein the precipitate is a porous crystal containing calcium carbonate.
The structure according to claim 6 or 7 , wherein the conductor is a carbon material.
The structure according to claim 8 , wherein the carbon material is carbon cloth.
A device for recovering heavy metal ions from treated water containing heavy metal ions, A structure according to any one of claims 6 to 9 , and an apparatus comprising means for supplying electrons to the conductor.
A method for accumulating microorganisms in treated water that contains heavy metal ions and has the ability to metabolize heavy metal ions, This includes placing a conductor in the water to be treated, and supplying electrons to the conductor to form a precipitate in which the microorganisms accumulate. The heavy metal ion is an ion of one or more metals selected from the group consisting of iron, manganese, arsenic, and antimony. The method wherein the microorganism is a microorganism belonging to the class Gamma-Proteobacteria that has a 16S rRNA gene consisting of (a1), (b1), (a2), (b2), (aa), or (bb) as described below; (a1) A polynucleotide consisting of the sequence described in Sequence ID No. 1, (a2) A polynucleotide consisting of the sequence described in Sequence ID No. 3, (b1) A polynucleotide consisting of the sequence described in Sequence ID No. 2, (b2) A polynucleotide consisting of the sequence described in Sequence ID No. 4 , (aa) A polynucleotide consisting of a sequence having 98.0% or more identity with the base sequence of Sequence ID No. 1 or 3, (bb) A polynucleotide consisting of a sequence having 98.0% or more identity with the base sequence of Sequence ID No. 2 or 4.

Description

This invention relates to a method for recovering heavy metal ions. More specifically, it relates to a method for recovering heavy metal ions from treated water containing heavy metal ions and inhabiting microorganisms with heavy metal metabolic capabilities. Furthermore, this invention relates to a structure and apparatus for recovering heavy metals. Moreover, this invention relates to a method for accumulating microorganisms in the treated water. Mining wastewater generated from mining development and other activities contains heavy metal ions, raising concerns about pollution impacts on agriculture and the environment, and requiring long-term treatment. Various methods have been developed and continuously improved to remove heavy metal ions from mining wastewater. Methods for treating water containing heavy metal ions, such as mine wastewater, can be broadly classified into active treatments that utilize chemicals or electricity, and passive treatments that utilize energy obtained from the natural environment, such as gravity, microbial metabolism, and photosynthesis. Classical active treatments include methods such as adding slaked lime to precipitate heavy metal ions as hydroxides and electrodeposition. Passive treatments include, for example, the long-established method of oxidizing divalent iron salts in mine wastewater using iron-oxidizing bacteria. While methods using iron-oxidizing bacteria are useful for removing and recovering iron, they cannot be applied to the removal of other harmful metals or the recovery of useful metals at low concentrations. In contrast, Patent Document 1 discloses a mine wastewater treatment method that includes a dearsenication step in which arsenic-containing ions are adsorbed by an adsorbent, along with a treatment step using iron-oxidizing bacteria, and states that this method is applicable to mine wastewater containing heavy metals other than iron. Japanese Patent Publication No. 2005-58955 This figure shows the results of X-ray diffraction measurements of the precipitate formed on the cathode surface in the example.This is an electron microscope image of the precipitate accumulated on the cathode surface in the example.This graph shows the relative frequency distribution of constituent microorganisms based on OTU (Operational Taxonomic Unit) analysis of 97% sequence homology of 16S rRNA genes in the microbial community accumulated on the cathode surface in the example.This is a phylogenetic tree based on 16S rRNA genes of the dominant strains (ASV1, ASV3, ASV4, ASV5) and their relatives in the microbial community accumulated in the precipitate on the cathode surface in the example. The phylogenetic tree was constructed using the neighbor joining method, and the letters in parentheses are GenBank accession numbers. The present invention will now be described in detail. While the following descriptions of constituent elements may be based on representative embodiments and specific examples, the present invention is not limited to such embodiments. <Method for recovering heavy metal ions> The present invention provides a method for recovering heavy metal ions, which includes placing a conductor in the water to be treated and supplying electrons to the conductor. [Water to be treated] The water to be treated in the method of the present invention contains heavy metal ions. Preferably, the water to be treated contains calcium ions in addition to heavy metal ions. Preferably, the water to be treated contains bicarbonate ions. Furthermore, the water to be treated is water in which microorganisms capable of metabolizing heavy metals inhabit. In the method of the present invention, the water to be treated is water in an environment in which microorganisms capable of metabolizing heavy metals inhabit, or water collected from such an environment. Examples of water to be treated include mine wastewater (water and wastewater) (mine drainage, etc.), factory wastewater, groundwater, and environmental water (river water, lake water, seawater, etc.). The water to be treated may be sludge, muddy water, or these suspended in water. Microorganisms capable of metabolizing heavy metal ions inhabit water in environments containing heavy metal ions, such as mine wastewater and factory effluent. Furthermore, groundwater and environmental water also contain heavy metal ions, and many microorganisms utilize these ions for their life activities. [Microorganisms with heavy metal metabolism capabilities] In this specification, heavy metal metabolic ability means the ability to utilize heavy metals (heavy metal ions and/or nonionic heavy metals) as substrates for redox reactions, and in particular, the ability to utilize heavy metals as substrates for energy production necessary for maintaining life. In this specification, microorganisms with heavy metal metabolic ability mean microorganisms that can continue to live in an environment where heavy metals are present, and in particular, microorgan