Extreme thermophilic ore-leaching bacteria as well as culture method and application thereof

Abstract

The invention discloses an extreme thermophilic ore leaching bacterium as well as a culture method and application thereof, and relates to the technical field of microorganisms, the extreme thermophilic ore leaching bacterium is Acidibacter sp.Biometek-WZ-1, can heterotrophically grow under the conditions of high temperature (more than 65 DEG C) and low acid (pH < 1.8), and can be used for leaching low-grade sulfide ore in an iron oxidation leaching system. The strain is stable in activity, good in adaptability and high in leaching efficiency, and is mainly used for leaching low-grade complex chalcopyrite in low-grade sulfide ore. The culture method of the extremely thermophilic bacteria provided by the invention is particularly suitable for breeding of industrial mineral leaching bacteria, and the bred bacteria have the characteristics of stable activity, high mineral tolerance, difficulty in degradation and stable leaching performance.

Description

Technical Field

[0001] This application relates to the field of microbial technology, and particularly to an extremely thermophilic ore-leaching bacterium, its cultivation method and application. Background Art

[0002] Biohydrometallurgy technology has environmental and economic advantages in the development of low-grade chalcopyrite. However, due to the high lattice energy of chalcopyrite and the easy formation of a surface passivation layer, the copper leaching rate of heap leaching at normal temperature (10°C - 40°C) is usually lower than 20%, which limits its industrial application. Currently, the leaching of chalcopyrite mainly relies on mesophilic bacteria and moderately thermophilic bacteria, such as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. However, the leaching efficiency of these bacterial strains is limited in high-temperature and high-acid environments, and it is difficult to break through the surface passivation layer of chalcopyrite.

[0003] To improve the leaching efficiency, researchers have turned to moderately thermophilic bacteria and extremely thermophilic bacteria, such as Acidithiobacillus caldus and Leptospirillum ferriphilum. However, these bacterial strains still have passivation problems. Although extremely thermophilic bacteria (such as archaea) can efficiently leach chalcopyrite and solve the problem of the passivation layer, due to the lack of a cell wall, it is difficult to purify, separate and subcultivate them under low-acid and high-temperature conditions, and the ore-leaching ability is prone to decline, which limits their practical application.

[0004] Existing research has proven that extremely thermophilic bacteria can efficiently leach chalcopyrite, improve the leaching efficiency by solving the passivation layer problem, and the enhanced leaching of various chalcopyrites by extremely thermophilic bacteria is the most likely method to achieve and has the highest economic benefits. However, extremely thermophilic bacteria are also sensitive to the environment, difficult to withstand high shear stress and pulp concentration, and are prone to breakage and death. There are still problems in the breeding and optimized cultivation research of extremely thermophilic bacteria for efficient chalcopyrite leaching, such as difficult purification, separation, detection, regulation, easy death, easy decline of ore-leaching ability, and unclear ore-leaching effect. Summary of the Invention

[0005] This application provides an extremely thermophilic ore-leaching bacterium, its cultivation method and application, so as to solve at least some of the above problems existing in the existing extremely thermophilic ore-leaching bacteria.

[0006] In a first aspect, the present application provides an extremely thermophilic ore-leaching bacterium, which is Acidibacter sp. Biometek-WZ-1, with a deposit number of CCTCC NO: M20242620. The deposit unit of this strain is the China Center for Type Culture Collection; the address is: Wuhan University, Bayi Road, Wuchang District, Wuhan City, Hubei Province, China; the deposit date is: November 21, 2024.

[0007] In a second aspect, the present application provides a method for culturing the extremely thermophilic ore-leaching bacterium as described in the first aspect above. The method includes:

[0008] Obtain water samples and soil samples from sulfuric thermal springs;

[0009] Based on the water samples and soil samples of the sulfuric thermal springs, determine the formula of the culture medium;

[0010] Use the culture medium to enrich the bacteria in the water samples and / or soil samples to obtain a bacterial suspension;

[0011] Successively domesticate the bacteria in the bacterial suspension for sulfur oxidation ability, iron oxidation ability, and mineral tolerance culture to obtain an extremely thermophilic ore-leaching bacterium.

[0012] In some embodiments, the formula of the culture medium is: CaCl 0.01 - 0.07 g / L, KCl 0.1 - 0.15 g / L, (NH4)2SO4 2.0 - 4.0 g / L, K2HPO4 0.1 - 1.0 g / L, MgSO4 0.1 - 0.5 g / L, FeSO4·7H2O 10.0 - 44.2 g / L, yeast powder 0.01 - 0.2 g / L, S 0.5 - 1 g / L.

[0013] In some embodiments, the step of using the culture medium to enrich the bacteria in the water samples and / or soil samples to obtain a bacterial suspension includes:

[0014] Add 95 mL of the culture medium to a 250 mL conical flask, and add 1% - 5% of low-grade chalcopyrite to obtain a mixed culture medium;

[0015] Adjust the pH value of the mixed culture medium to 1.8 ± 0.5 with dilute sulfuric acid, inoculate the bacteria in 5% of the water samples and / or soil samples, and incubate at a constant temperature in a shaker at a culture temperature of 55°C - 70°C and a rotation speed of 180 r / min - 300 r / min;

[0016] Under the same culture conditions, transfer the bacteria regularly 3 - 5 times to obtain the enriched bacterial suspension.

[0017] In some embodiments, the process of domestication of the sulfur oxidation ability and iron oxidation ability of the bacteria in the bacterial suspension is as follows:

[0018] Inoculate the strain in the bacterial suspension into the culture medium, adjust the pH value to 1.5 - 2.0, place it in a shaker at a temperature of 55 - 70 °C and a rotation speed of 180 - 300 r / min, and conduct sulfur oxidation experiments at different concentrations respectively;

[0019] Under the same culture environment, select the strain of the group with the best oxidation effect in the sulfur oxidation experiment, conduct 5 - 10 subculture cultivations, and when the sulfur oxidation time of this strain is shortened to within 50% of the original oxidation time and the strain grows stably, obtain the preliminarily domesticated strain;

[0020] Gradually increase the sulfur content in the culture, cultivate the preliminarily domesticated strain until the sulfur concentration is too high and the strain dies, and use the strain before the death as the strain domesticated by the sulfur oxidation experiment;

[0021] Inoculate the strain domesticated by the sulfur oxidation experiment into the culture medium, and conduct the domestication of the iron oxidation ability according to the process of sulfur oxidation ability domestication to obtain the strain domesticated by the iron oxidation experiment.

[0022] In some embodiments, the process of mineral tolerance cultivation of the bacteria in the bacterial suspension is as follows:

[0023] Inoculate the strain domesticated by the iron oxidation experiment into the culture medium, adjust the pH value to 1.5 - 2.0, place it in a shaker at a temperature of 55 - 70 °C and a rotation speed of 180 - 300 r / min, and conduct mineral leaching experiments at different concentrations respectively;

[0024] Under the same culture environment, select the strain of the group with the best leaching effect in the mineral leaching experiment, conduct 5 - 10 subculture cultivations, and when the leaching time of this strain is shortened to within 50% of the original leaching time and the strain grows stably, obtain the preliminarily tolerant strain;

[0025] Gradually increase the mineral concentration in the culture, cultivate the preliminarily tolerant strain until the mineral concentration is too high and the strain dies, and use the strain before the death as the extremely thermophilic leaching bacterium.

[0026] In a third aspect, an embodiment of the present application proposes an application of an extremely thermophilic leaching bacterium, and the extremely thermophilic leaching bacterium is used to leach low - grade sulfide ores and low - grade chalcopyrite in an iron - oxidation leaching system in a strongly acidic environment and a high - temperature environment.

[0027] In some embodiments, the pH value of the acidic environment is less than 1.8, and the temperature of the high - temperature environment is greater than 65 °C.

[0028] In some embodiments, the extremely thermophilic ore-leaching bacterium described in claim 1 is mixed with the low-grade sulfide ore to be leached. Under the leaching environment where the pH value is 1.8, the solid-liquid ratio of the low-grade sulfide ore to be leached to dilute sulfuric acid is 1% - 7%, the leaching temperature is 65°C - 70°C, and the rotation speed is 140 rpm - 150 rpm, the target metal is leached out.

[0029] This application has the following advantages: This application discloses an extremely thermophilic ore-leaching bacterium, its cultivation method and application. The extremely thermophilic bacterium is Acidibacter sp. Biometek-WZ-1, which can grow heterotrophically under high temperature (>65°C) and low acid (pH < 1.8) conditions, and can use this strain to leach low-grade sulfide ore in the iron-oxidizing leaching system. This strain has stable activity, good adaptability and high leaching efficiency, and is mainly used for leaching low-grade complex chalcopyrite in low-grade sulfide ore. The cultivation method of the extremely thermophilic bacterium provided in this application is particularly suitable for the breeding of industrial ore-leaching bacteria. The selected bacteria have the characteristics of stable activity, strong tolerance to minerals, not easy to degenerate, and stable leaching performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a KO database fitting heat map of a sampling sample provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0033] Although researchers believe that bioleaching of low-grade chalcopyrite is the general trend under the increasingly stringent environmental protection requirements and economic benefit requirements, and a large number of studies have been carried out on the environmental conditions and transformation mechanisms of the chalcopyrite bacterial leaching process, due to the high lattice energy and difficult dissolution of chalcopyrite itself, and the surface passivation phenomenon during the leaching process, etc., the leaching rate of low-grade chalcopyrite in heap leaching at normal temperature (10°C - 40°C) is extremely low, usually the leaching rate is below 20%, which severely restricts the application and development of this technology in industrial practice.

[0034] Leaching bacteria are the key factors determining the bioleaching effect of chalcopyrite. Different leaching bacteria have different metabolic pathways, so the mechanisms of chalcopyrite leaching are not the same. Under the conditions of different bacterial species on the same mineral and the same bacterial species on different minerals, the leaching behavior of chalcopyrite shows differences. While fully studying the properties of existing bacterial species, many researchers are also breeding bacterial species with stronger leaching ability. In addition to screening natural bacterial species from the natural environment, the breeding methods also include mutagenesis breeding, domestication breeding, conjugation breeding, cell fusion breeding, etc. However, due to the certain complexity and instability of genetic engineering breeding methods, and poor economy, few people currently adopt this method to breed leaching bacterial species. Mutagenesis breeding is to use chemical factors such as alkylating agents and base analogs, or physical factors such as ultraviolet rays and X-rays to change the properties of bacterial species at the DNA molecule or base level. Although it has no selectivity and is easy to mutate and difficult to pass on, due to its high feasibility in the laboratory, there have been relevant studies in recent years. Domestication breeding is the most widely used breeding method at present due to its economy and stability. It has the function of directional breeding and can relatively easily obtain the target bacterial species, and is suitable for culturing applicable bacterial species that can tolerate extreme environments such as toxic ions, heavy metal ions, and high temperatures.

[0035] The oxidation of sulfide minerals by microorganisms is an exothermic and acid-producing process. Therefore, in actual heap leaching, due to the abundance of substrates and the difficulty of gas-liquid transmission, the leaching system becomes an environment with high heat, high acid, and high iron. Such extreme living conditions make the microbial community in the leaching system relatively simple. Therefore, researchers focus on acidophilic iron-oxidizing bacteria and obligate sulfur-oxidizing bacteria, mainly Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. However, these two bacteria only have good leaching effects at room temperature and cannot adapt to the high temperature of the leaching system. Moreover, when mesophilic bacteria and moderately thermophilic bacteria act on chalcopyrite, surface passivants that are difficult to break through are easily formed on the surface of chalcopyrite, restricting the leaching rate of copper. Researchers have turned their attention to moderately thermophilic bacteria and extremely thermophilic bacteria, and isolated A. caldus, L. ferriphilum, and some archaea such as Ferroplasma sp.,

[0036] At present, the main leaching bacteria for chalcopyrite leaching are still mesophilic bacteria and moderately thermophilic bacteria, and there is a lack of some extremely thermophilic chalcopyrite-efficient leaching bacteria. Existing research has proved that extremely thermophilic bacteria can efficiently leach chalcopyrite, solve the problem of passivation layer, and improve the leaching efficiency. And due to the maturity of existing breeding and domestication technology means, population detection means, and microbial community regulation means, this method is the most likely to be realized and has the highest economic benefits among various enhanced chalcopyrite leaching methods.

[0037] However, there are still problems of chalcopyrite passivation during the leaching of these bacterial strains, making it difficult to achieve complete leaching. Most of the currently isolated extremely thermophilic ore-leaching bacteria are archaea. This type of bacteria lacks cell wall support and is difficult to purify, separate, detect, regulate, and is prone to death under low-acid and high-temperature conditions. Its ore-leaching ability is prone to decline, and its ore-leaching effect is not clear. It is difficult to subculture and apply in ore leaching practically.

[0038] Based on this, the present application aims to screen out extremely thermophilic bacteria with excellent phenotypes and exclusive high-efficiency leaching of low-grade chalcopyrite by breeding the ore-leaching bacterial strains of chalcopyrite, and improve the tolerance of this bacterial strain to toxic substances, mineral concentrations, and shear stress in the complex system of chalcopyrite leaching through domestication, maintain the stability of its leaching performance, and improve its efficiency in leaching low-grade chalcopyrite.

[0039] In the first aspect, an embodiment of the present application provides an extremely thermophilic ore-leaching bacterium, which is Acidibacter sp. Biometek-WZ-1, deposited in the China Center for Type Culture Collection (CCTCC), located at Wuhan University, Bayi Road, Wuchang District, Wuhan City, Hubei Province, China. The deposit date is November 21, 2024, and the deposit number is CCTCC NO: M20242620.

[0040] Since it is relatively difficult to isolate extremely thermophilic bacteria with good and stable ore-leaching effects by existing breeding and separation methods, based on this, in the second aspect, an embodiment of the present application provides a cultivation method to cultivate extremely thermophilic ore-leaching bacteria with good and stable ore-leaching effects. The method includes:

[0041] Step 1: Obtain water samples and soil samples from a sulfuric thermal spring.

[0042] The sampled samples are from a sulfuric thermal spring in a certain place in Yunnan, China. The average temperature at the sampling point where the samples are taken from the sulfuric thermal spring is about 70°C, and the average pH value is about 1.8. The average temperature of the sulfuric thermal spring is about 70°C, which is much higher than normal temperature and is suitable for screening extremely thermophilic bacteria that can survive and reproduce at high temperatures. At the same time, the strongly acidic environment with an average pH value of about 1.8 helps to screen out acid-tolerant bacterial strains, which can tolerate the high-acid conditions during ore leaching in bio-metallurgy. In addition, sulfuric thermal springs usually contain high concentrations of sulfides or elemental sulfur, which is suitable for screening bacterial strains with high-efficiency sulfur oxidation ability. Secondly, various metal ions (such as iron, copper, etc.) may be contained in the hot spring, which helps to screen out heavy-metal-tolerant bacterial strains, which can tolerate the toxicity of high-concentration metal ions during ore leaching.

[0043] Moreover, the extreme environment (high temperature, high acidity, high sulfur) of sulfur hot springs has a higher possibility of giving birth to unique microbial communities than other environments, and the probability of containing extreme thermophiles with efficient ore leaching ability is also relatively high. Since the bacterial strains in sulfur hot springs have naturally adapted to high temperature, high acidity and high sulfur environments, the difficulty and time of laboratory domestication are reduced. The bacterial strains in the natural environment have high environmental adaptability and genetic stability after long-term natural selection.

[0044] Step 2: Based on the water samples and soil samples of the sulfur hot spring, determine the formula of the culture medium.

[0045] Detect the water quality and soil sampling at this sampling point. Since the sampling environment is rich in elements such as S, Al, Fe, Mg, etc., considering the influence of various elements on the oxidation ability of bacterial strains, the formula of the culture medium is determined as follows: CaCl 0.01 - 0.07 g / L, KCl 0.1 - 0.15 g / L, (NH4)2SO4 2.0 - 4.0 g / L, K2HPO4 0.1 - 1.0 g / L, MgSO4 0.1 - 0.5 g / L, FeSO4·7H2O 10.0 - 44.2 g / L, yeast powder 0.01 - 0.2 g / L, S 0.5 - 1 g / L.

[0046] Optionally, the formula of the above culture medium can be: CaCl 0.01 g / L, KCl 0.1 g / L, (NH4)2SO4 2.0 g / L, K2HPO4 0.1 g / L, MgSO4 0.1 g / L, FeSO4·7H2O 10.0 g / L, yeast powder 0.01 g / L, S 0.5 g / L;

[0047] CaCl 0.07 g / L, KCl 0.15 g / L, (NH4)2SO4 4.0 g / L, K2HPO4 1.0 g / L, MgSO4 0.5 g / L, FeSO4·7H2O 44.2 g / L, yeast powder 0.2 g / L, S 1 g / L, etc.

[0048] Perform high-throughput sequencing and analysis on the above water samples to obtain a KO database fitting heat map (see Figure 1 ), and the genome of the synthetic iron complex outer membrane receptor protein exists in this sampling sample (as shown by the boxed part in Figure 1 ), indicating that there are sites on the cell membrane of the species that can combine with iron elements. At the same time, there are also functional genomes of enzyme proteins such as glutamate S transferase and Cu 2+ -transporting ATPase, indicating that its growth and reproduction may be related to S, Cu 2+ etc., and may also have a certain consumption of Fe, S, Cu 2+The ability. The results show that the culture medium containing the above components can be used to culture and domesticate the strains for leaching chalcopyrite iron ore, that is, the target strains required in the strains obtained by the above culture.

[0049] Step 3: Enrich and culture the strains in the water sample and / or soil sample with the culture medium to obtain a bacterial suspension.

[0050] Specifically, enriching and culturing the strains in the water sample and / or soil sample with the culture medium to obtain a bacterial suspension includes:

[0051] First, add 95 mL of the culture medium to a 250 mL conical flask, add 1%-5% of low-grade chalcopyrite to obtain a mixed culture medium, then adjust the pH value of the mixed culture medium to 1.8 ± 0.5 with dilute sulfuric acid, inoculate 5% of the strains in the water sample and / or soil sample, and perform constant-temperature culture in a shaker at a culture temperature of 55°C - 70°C and a rotation speed of 180 r / min - 300 r / min. Finally, under the same culture conditions, transfer the strains regularly 3 - 5 times to obtain the enriched bacterial suspension.

[0052] Optionally, the concentration of the above dilute sulfuric acid is 0.1 mol / L, the above inoculated sample is preferably a water sample, the addition amount of low-grade chalcopyrite can be 1%, 2%, 3%, 4%, 5%, etc., the culture temperature can be 55°C, 60°C, 65°C, 70°C, etc., and the rotation speed of the shaker can be 180 r / min, 190 r / min, 200 r / min, 210 r / min, 220 r / min, 230 r / min, 240 r / min, 250 r / min, 260 r / min, 270 r / min, 280 r / min, 290 r / min, 300 r / min, etc. The number of times of transferring the strains can be 3 times, 4 times, 5 times, etc. In the art, usually, the number of bacteria in the bacterial suspension obtained by transferring the strains 3 - 5 times can meet the subsequent culture requirements. If there are other requirements, the number of times of transferring the strains can also be extended to 6 times or 7 times.

[0053] Using the above specific culture medium and adding low-grade chalcopyrite to it, the strains that cannot grow under the above specific culture conditions (strong acid, high temperature) or are intolerant to the above target minerals cannot survive. Through this enrichment method, the strains contained in the sampled samples can be further screened.

[0054] Step 4: Domesticate the bacteria in the bacterial suspension for sulfur oxidation ability, iron oxidation ability, and mineral tolerance culture in turn to obtain extremely thermophilic ore-leaching bacteria.

[0055] After the enrichment culture of the strains in the sampling sample, the surviving strains are successively domesticated for sulfur oxidation ability, iron oxidation ability, and mineral tolerance culture, so that the domesticated strains can be more stable and better applied to the field of ore leaching. After sulfur oxidation ability domestication, strains that can efficiently oxidize sulfide minerals can be screened out, enhancing their ability to oxidize and decompose sulfides. After iron oxidation ability domestication, strains that can efficiently oxidize ferrous ions can be screened out, promoting the dissolution of iron in minerals and improving the leaching efficiency. After mineral tolerance culture, the tolerance of the strains to the target minerals is enhanced, enabling them to grow stably and play a role in ore leaching during the leaching process.

[0056] In addition, sulfide minerals such as chalcopyrite are prone to form a surface passivation layer during the leaching process, hindering further leaching. The highly efficient sulfur-oxidizing and iron-oxidizing strains obtained through domestication can effectively break through the passivation layer and improve the leaching rate of copper.

[0057] Furthermore, extreme thermophiles can grow in a high-temperature (55 - 70 °C) environment and adapt to the high-temperature conditions during ore leaching. The domesticated strains can grow stably in a highly acidic (such as pH 1.5 - 2.0) environment and adapt to the highly acidic conditions of the leaching system. Through mineral tolerance culture, the strains can tolerate high concentrations of metal ions (such as Cu 2+ 、Fe 3+ ) generated during the ore leaching process.

[0058] In an optional embodiment, the process of domesticating the sulfur oxidation ability and iron oxidation ability of the bacteria in the bacterial suspension is as follows:

[0059] First, the strains in the bacterial suspension are inoculated into the culture medium, the pH value is adjusted to 1.5 - 2.0, and it is placed in a shaker at a temperature of 55 - 70 °C and a rotation speed of 180 - 300 r / min for sulfur oxidation experiments at different concentrations. Then, in the same culture environment, the strains in the group with the best oxidation effect in the sulfur oxidation experiment are selected for 5 - 10 subculture generations. When the sulfur oxidation time of the strains is shortened to within 50% of the original oxidation time and the strains grow stably, the preliminarily domesticated strains are obtained. Finally, the sulfur content of the culture is gradually increased to culture the preliminarily domesticated strains until the sulfur concentration is too high and the strains die, and the strains before the death are used as the strains domesticated by the sulfur oxidation experiment.

[0060] In the above process, the concentration of sulfur can be 0.1 g / L, 0.5 g / L, 1 g / L, 10 g / L, etc. Preferably, the strains in the group with the best oxidation effect in the sulfur oxidation experiment are the strains corresponding to the 1 g / L sulfur concentration group. When the sulfur concentration is 1 g / L, the strains have good adaptability and grow stably.

[0061] Inoculate the strain domesticated through the sulfur oxidation experiment into the culture medium, and domesticate the iron oxidation ability according to the process of sulfur oxidation ability domestication to obtain the strain domesticated through the iron oxidation experiment.

[0062] The process of iron oxidation ability domestication is the same as that of sulfur oxidation ability domestication, except that the added sulfur is replaced by iron. In the above process, the concentration of iron can be 2 g / L, 4 g / L, 6 g / L, 8 g / L, etc. Preferably, the strain of the group with the best oxidation effect in the iron oxidation experiment is the strain corresponding to the 4 g / L sulfur concentration group. When the iron concentration is 4 g / L, the strain has good adaptability and stable growth.

[0063] In an alternative embodiment, the process of culturing the bacteria in the bacterial suspension to be mineral-tolerant is as follows:

[0064] First, inoculate the strain domesticated through the iron oxidation experiment into the culture medium, adjust the pH value to 1.5 - 2.0, and place it in a shaker at a temperature of 55 - 70 °C and a rotation speed of 180 - 300 r / min to conduct mineral leaching experiments at different concentrations; then, under the same culture environment, select the strain of the group with the best leaching effect in the mineral leaching experiment and conduct 5 - 10 subculture cultivations. When the leaching time of this strain is shortened to within 50% of the original leaching time and the strain grows stably, obtain the initially tolerant strain; finally, gradually increase the mineral concentration of the culture and culture the initially tolerant strain until the mineral concentration is too high and the strain dies, and use the strain before the death of the strain as the extreme thermophilic leaching bacterium.

[0065] Among them, in the above mineral leaching experiment, the concentration of the mineral can be 1%, 2%, 5%, 8%, 11%, etc. Preferably, the strain of the group with the best oxidation effect in the mineral leaching experiment is the strain corresponding to the 1% concentration group. When the mineral concentration is 1%, the strain has good adaptability and stable growth.

[0066] The specific operations in the sulfur oxidation experiment, iron oxidation experiment, and mineral tolerance experiment proposed above are the same as the conventional methods and will not be elaborated here. The actual achievable operation method shall prevail.

[0067] The strain obtained through the above cultivation process is the extreme thermophilic leaching bacterium. The domesticated strain has high genetic stability and environmental adaptability, can maintain stable growth and metabolic activity during the leaching process, and reduce the risk of strain decline or failure. The highly efficient leaching strain obtained through domestication can significantly improve the leaching efficiency, shorten the leaching time, thereby reducing the energy consumption and cost of the leaching process. Reduce the dependence on chemical leaching agents and reduce environmental pollution and treatment costs.

[0068] Through the above-mentioned processes of breeding, enriching, and culturing extreme thermophiles, extreme thermophiles with stable activity, strong tolerance to minerals, not easily degraded, and stable leaching performance can be obtained. Based on this characteristic, the above method is more suitable for the breeding of industrial ore-leaching bacteria.

[0069] In a third aspect, an embodiment of the present application provides an application of an extreme thermophilic ore-leaching bacterium, which is used to leach low-grade sulfide ores in an iron-oxidizing leaching system under a strongly acidic environment and a high-temperature environment.

[0070] In the embodiment of the present application, sulfide ore refers to ore in which metals exist in the form of sulfides (such as chalcopyrite CuFeS2, pyrite FeS2). The "low grade" in low-grade sulfide ore means that the content of useful metals (such as copper, zinc, lead, etc.) or target minerals (such as chalcopyrite, sphalerite, etc.) in the ore is significantly lower than the economic threshold for industrial mining.

[0071] In the present application, the above low-grade sulfide ore can be selected as low-grade chalcopyrite.

[0072] Optionally, the pH value of the above strongly acidic environment is less than 1.8. For example, it can be 1.8, 1.7, 1.6, 1.5, etc. The temperature of the above high-temperature environment is greater than 65 °C. For example, it can be 66 °C, 67 °C, 68 °C, 69 °C, 70 °C, 75 °C, 80 °C.

[0073] Specifically, the above extreme thermophilic ore-leaching bacterium is mixed with the low-grade sulfide ore to be leached. Under the leaching environment with a pH value of 1.8, a solid-liquid ratio of the low-grade sulfide ore to be leached to dilute sulfuric acid of 1% - 7%, a leaching temperature of 65 °C - 70 °C, and a rotation speed of 140 rpm - 150 rpm, the target metal is leached.

[0074] For example, if the above low-grade sulfide ore mixture is low-grade chalcopyrite, the target metal obtained through the above leaching process is copper.

[0075] Next, a specific embodiment is used to further illustrate an extreme thermophilic ore-leaching bacterium, its culture method, and application proposed in the present application.

[0076] Example 1 Culture Method

[0077] Obtain a water sample from a sulfur hot spring;

[0078] Add 95 mL of the medium into a 250 mL conical flask, and add 5% of low-grade chalcopyrite to obtain a mixed medium. The formula of the medium is CaCl 0.04 g / L, KCl 0.12 g / L, (NH4)2SO4 2.3 g / L, K2HPO4 0.4 g / L, MgSO4 0.3 g / L, FeSO4·7H2O 30.0 g / L, yeast powder 0.12 g / L, S 0.7 g / L;

[0079] Adjust the pH value of the mixed medium to 1.8 ± 0.5 with 0.1 mol / L dilute sulfuric acid, inoculate the strains in 5% water samples and / or soil samples, and carry out constant-temperature culture in a shaker at a culture temperature of 70 °C and a rotation speed of 200 r / min;

[0080] Under the same culture conditions, transfer the strains regularly for 5 times to obtain an enriched bacterial suspension;

[0081] Inoculate the strains in the bacterial suspension into the medium, adjust the pH value to 1.5 with 0.1 mol / L dilute sulfuric acid, and place it in a shaker at a temperature of 70 °C and a rotation speed of 200 r / min to carry out sulfur oxidation experiments at different concentrations (0.1 g / L, 0.5 g / L, 1 g / L, 10 g / L) respectively; Take the strain with a sulfur concentration of 1 g / L, and carry out 8 subcultures of this strain under the same culture environment. When the sulfur oxidation time of this strain is shortened to within 50% of the original oxidation time and the strain grows stably, obtain a preliminarily domesticated strain; Gradually increase the sulfur content of the culture, and culture the preliminarily domesticated strain until the sulfur concentration is too high and the strain dies. Take the strain before the death of the strain as the strain domesticated by the sulfur oxidation experiment;

[0082] Inoculate the strain domesticated by the sulfur oxidation experiment into the medium, and carry out domestication of the iron oxidation ability according to the process of sulfur oxidation ability domestication to obtain a strain domesticated by the iron oxidation experiment, where the iron concentration is 2 g / L, 4 g / L, 6 g / L, 8 g / L, and select the strain with an iron concentration of 4 g / L for 8 subcultures.

[0083] Inoculate the strain domesticated by the iron oxidation experiment into the culture medium, adjust the pH value to 1.5 with 0.1 mol / L dilute sulfuric acid, place it in a shaker at a temperature of 70 °C and a rotation speed of 200 r / min, and conduct mineral leaching experiments at different concentrations (1%, 2%, 5%, 8%, 11%); then, determine the strain in the group with the best leaching effect in the mineral leaching experiment, and conduct 8 subcultures of this strain under the same culture environment. When the leaching time of this strain is shortened to within 50% of the original leaching time and the strain grows stably, a preliminarily tolerant strain is obtained; finally, gradually increase the mineral concentration of the culture, culture the preliminarily tolerant strain until the mineral concentration is too high and the strain dies, and use the strain before the death of the strain as the extremely thermophilic leaching bacterium. Among them, the strain with a mineral concentration of 1% is selected for subculture.

[0084] Leaching method of Example 2

[0085] Mix the strain (extremely thermophilic leaching bacterium) cultured in Example 1 with the low-grade chalcopyrite to be leached. Under the leaching environment with a pH value of 1.8, a solid-liquid ratio of 7% of the low-grade chalcopyrite to be leached and dilute sulfuric acid, a leaching temperature of 70 °C, and a rotation speed of 150 rpm, the leaching cycle is 15 d, and the copper leaching rate is 55%.

[0086] In this process, sulfur powder and iron powder are used to simulate the low-grade chalcopyrite to be leached. When the solid-liquid ratio of the low-grade chalcopyrite to be leached and dilute sulfuric acid is 7%, the concentrations of sulfur powder and iron powder are 1 g / L and 44.2 g / L respectively.

[0087] Leaching method of Example 3

[0088] Mix the strain cultured in Example 1 with the low-grade chalcopyrite to be leached. Under the leaching environment with a pH value of 1.8, a solid-liquid ratio of 1% of the low-grade chalcopyrite to be leached and dilute sulfuric acid, a leaching temperature of 70 °C, and a rotation speed of 140 rpm, the leaching cycle is 25 d, and the copper leaching rate is 78.07%.

[0089] In this process, sulfur powder and iron powder are used to simulate the low-grade chalcopyrite to be leached. When the solid-liquid ratio of the low-grade chalcopyrite to be leached and dilute sulfuric acid is 1%, the concentrations of sulfur powder and iron powder are 0.1 g / L and 22.1 g / L respectively.

[0090] Leaching method of Example 3

[0091] Mix the strain cultured in Example 1 with the low-grade chalcopyrite to be leached. Under the leaching environment with a pH value of 1.8, a solid-liquid ratio of 1% of the low-grade chalcopyrite to be leached and dilute sulfuric acid, a leaching temperature of 70 °C, and a rotation speed of 140 rpm, the leaching cycle is 28 d, and the copper leaching rate is 94%.

[0092] In this process, sulfur powder and iron powder were used to simulate the low-grade chalcopyrite to be leached. When the solid-liquid ratio of the mineral to dilute sulfuric acid was 1%, the concentrations of sulfur powder and iron powder were 0.1 g / L and 22.1 g / L respectively.

[0093] The extremely thermophilic bacterium (Acidibacter sp. Biometek-WZ-1) disclosed in this application can grow heterotrophically under high temperature (>65 °C) and low acid (pH < 1.8) conditions, and this strain can be used to leach low-grade sulfide ores in an iron-oxidizing leaching system. This strain has stable activity, good adaptability, and high leaching efficiency, and is mainly used for leaching low-grade complex chalcopyrite in low-grade sulfide ores. The cultivation method of the extremely thermophilic bacterium provided in this application is particularly suitable for the breeding of industrial ore-leaching bacteria, and the selected bacteria have the characteristics of stable activity, strong tolerance to minerals, not easy to degenerate, and stable leaching performance.

[0094] The above has introduced in detail an extremely thermophilic ore-leaching bacterium and its cultivation method and application provided by this application. Specific examples are used in this article to elaborate on the principle and implementation mode of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, based on the idea of this application, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. An extremely thermophilic ore-leaching bacterium, characterized in that, The extremely thermophilic ore-leaching bacterium is Acidibacter sp. Biometek-WZ-1, and the deposit number is CCTCC NO: M 20242620.

2. A cultivation method of extremely thermophilic ore leaching bacteria, characterized in that, The method includes: Obtaining water samples and soil samples from sulfuric hot springs; Determining the formula of the culture medium based on the water samples and soil samples of the sulfuric hot springs; Enriching the bacteria in the water samples and / or soil samples with the culture medium to obtain a bacterial suspension; Successively domesticating the bacteria in the bacterial suspension for sulfur oxidation ability, iron oxidation ability, and mineral tolerance culture to obtain extremely thermophilic ore-leaching bacteria.

3. The culturing method of the extremely thermophilic ore-leaching bacterium according to claim 2, characterized in that, The formula of the culture medium is: CaCl 0.01 - 0.07 g / L, KCl 0.1 - 0.15 g / L, (NH4)2SO4 2.0 - 4.0 g / L, K2HPO4 0.1 - 1.0 g / L, MgSO4 0.1 - 0.5 g / L, FeSO4·7H2O 10.0 - 44.2 g / L, yeast powder 0.01 - 0.2 g / L, S 0.5 - 1 g / L.

4. The culturing method of the extremely thermophilic ore-leaching bacterium according to claim 2, characterized in that, The step of enriching the bacteria in the water samples and / or soil samples with the culture medium to obtain a bacterial suspension includes: Adding 95 mL of the culture medium into a 250 mL conical flask, and adding 1% - 5% of low-grade chalcopyrite to obtain a mixed culture medium; Adjusting the pH value of the mixed culture medium to 1.8 ± 0.5 with dilute sulfuric acid, inoculating 5% of the bacteria in the water samples and / or soil samples, and performing constant-temperature culture in a shaker at a culture temperature of 55°C - 70°C and a rotation speed of 180 r / min - 300 r / min; Under the same culture conditions, transferring the bacteria 3 - 5 times regularly to obtain the enriched bacterial suspension.

5. The culturing method of the extremely thermophilic ore-leaching bacterium according to claim 2, wherein The process of domesticating the bacteria in the bacterial suspension for sulfur oxidation ability and iron oxidation ability is as follows: Inoculating the bacteria in the bacterial suspension into the culture medium, adjusting the pH value to 1.5 - 2.0, and placing it in a shaker at a temperature of 55 - 70°C and a rotation speed of 180 - 300 r / min to perform sulfur oxidation experiments at different concentrations; Under the same culture environment, selecting the bacteria in the group with the best oxidation effect in the sulfur oxidation experiment, performing 5 - 10 subculture cultivations, and obtaining the preliminarily domesticated bacteria when the sulfur oxidation time of the bacteria is shortened to within 50% of the original oxidation time and the bacteria grow stably; Gradually increasing the sulfur content of the culture, culturing the preliminarily domesticated bacteria until the sulfur concentration is too high and the bacteria die, and using the bacteria before the bacteria die as the bacteria domesticated by the sulfur oxidation experiment; Inoculating the bacteria domesticated by the sulfur oxidation experiment into the culture medium, and performing iron oxidation ability domestication according to the process of sulfur oxidation ability domestication to obtain the bacteria domesticated by the iron oxidation experiment.

6. The culturing method of the extremely thermophilic ore-leaching bacterium according to claim 5, characterized in that, The process of performing mineral tolerance culture on the bacteria in the bacterial suspension is as follows: Inoculating the bacteria domesticated by the iron oxidation experiment into the culture medium, adjusting the pH value to 1.5 - 2.0, and placing it in a shaker at a temperature of 55 - 70°C and a rotation speed of 180 - 300 r / min to perform mineral leaching experiments at different concentrations; Under the same culture environment, select the strain with the best leaching effect in the mineral leaching experiment and conduct 5-10 subcultures. When the leaching time of the strain is shortened to within 50% of the original leaching time and the strain grows stably, a preliminarily tolerant strain is obtained; Gradually increase the mineral concentration of the culture and culture the preliminarily tolerant strain until the mineral concentration is too high and the strain dies. Use the strain before the death of the strain as the extremely thermophilic mineral leaching bacterium.

7. Application of an extremely thermophilic ore-leaching bacterium, characterized in that, The extremely thermophilic mineral leaching bacterium is used to leach low-grade sulfide ores in an iron oxidation leaching system under a strong acidic environment and a high-temperature environment.

8. The application according to claim 7, wherein The pH value of the acidic environment is less than 1.8, and the temperature of the high-temperature environment is greater than 65 °C.

9. The application according to claim 7, wherein Mix the extremely thermophilic mineral leaching bacterium described in claim 1 with the low-grade sulfide ore to be leached, and under the leaching environment with a pH value of 1.8, a solid-liquid ratio of the low-grade sulfide ore to be leached to dilute sulfuric acid of 1%-7%, a leaching temperature of 65 °C-70 °C, and a rotation speed of 140 rpm-150 rpm, leach to obtain the target metal.

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