CN102154142A - Microorganism for promoting black nightshade to remove trace cadmium pollution in water and method for removing cadmium pollution - Google Patents

Abstract

The invention provides a microorganism that promotes nightshade nightshade to remove trace cadmium pollution in water and a method for removing cadmium pollution, and uses the high-efficiency absorption characteristic of cadmium of the superaccumulative plant nightshade to purify drinking water polluted by cadmium. Solanum solanum was cultivated in hydroponics, and its root growth was promoted by inoculating Chryseobacterium sp.LKS03. When purifying drinking water, immerse the roots of Solanum nigrum plants in drinking water containing cadmium pollution. Each plant of Solanum nigrum will purify about 1-1.2 liters of drinking water in one purification cycle, depending on the concentration of cadmium ions in the water sample (not high 200μg/L), the required purification time ranges from 2 hours to 12 hours, and the ability of Solanum nigrum plants to purify water samples is the best in the 45th-80th day of its culture cycle. The method has the advantages of good removal effect of cadmium pollution in drinking water, simple operation and wide application range, and has great application potential in drinking water purification.

Description

A kind of microorganism that promotes nightshade to remove trace cadmium pollution in water and method for removing cadmium pollution

technical field

The invention relates to a biological purification method for drinking water polluted by trace amounts of cadmium, in particular to a method for removing trace amounts of cadmium pollution in water by using black nightshade and the microorganisms used.

Background technique

Industrial development is often accompanied by environmental pollution. The problem of heavy metal pollution in water caused by the discharge of waste water and residue in the "three industrial wastes" is becoming more and more serious, which not only destroys the ecological environment, but also directly or indirectly endangers people's health. Heavy metal cadmium pollution mainly comes from printing and dyeing, pesticides, ore mining, smelting and other industries. Long-term intake of trace amounts of cadmium will seriously damage the liver, kidney and other organs of the human body, and cause various diseases. Osteopathy caused by cadmium pollution in Europe and Japan is a common disease caused by cadmium poisoning in cadmium-polluted areas.

Commonly used methods to remove cadmium pollution in drinking water mainly include: flocculant filtration method, lime precipitation method, ion exchange method, electrolysis method, etc., but these methods have secondary pollution, high cost, and repeated use during the treatment process. Poor performance, complex process and other defects. Therefore researching out a kind of efficient, environment-friendly, low-cost method is the trend of current technological development, the biological purification method that the present invention adopts, will solve a series of problems that existing method occurs.

Invention content:

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, and provide a microorganism that promotes the removal of trace cadmium pollution in water by Solanum nigrum and a method for removing cadmium pollution. The method is simple to operate, economical and efficient, and environmentally friendly.

A microorganism that promotes the removal of trace cadmium pollution in water from Solanum nigrum is Chryseobacterium sp.LKS03, and its preservation number is CCTCC NO: M 2010236.

Apply the method for promoting the removal of trace cadmium pollution in water by microorganisms, sterilize the surface of Solanum nigrum seeds, soak them in the Chryseobacterium sp. ; After another 30 days the nightshade plants were used for water purification.

The solanum nigrum seeds are soaked in 75% alcohol solution for 15 seconds to sterilize the surface, rinsed with clear water for 3 times, dried and used for soaking in endophytic bacteria solution.

The preparation process of the bacterial solution is as follows: Pick the Chryseobacterium sp.LKS03 bacterial strain and inoculate it into 100ml liquid LB medium for expansion and cultivation for 12 hours, centrifuge at 4000 rpm for 5 minutes, pour off the supernatant, and use 100ml 1/4 Concentration of modified Hoagland's solution to resuspend bacterial cells to obtain endophyte inoculum.

The sowing is to spread the vermiculite in the tray with a thickness of 4-6 cm, pour the modified Hoagland solution with 1/4 concentration, and sow nightshade seeds therein.

Said hydroponics adopts 1/4 concentration of modified Hoagland's solution as the hydroponic nutrient solution, and the nutrient solution is changed every 4-6 days and constantly replenished.

The formulation of the improved Hoagland's solution with 1/4 concentration is: KNO ₃ 125mg/L; KH ₂ PO ₄ 35mg/L; NH ₄ H ₂ PO ₄ 20mg/L; MgSO ₄ ·7H ₂ O 125mg/L; Ca(NO ₃ ) ₂ .4H ₂ O 235 mg/L; FeSO ₄ .7H ₂ O 10 mg/L.

The time for the said nightshade plant to purify water is 30-40 days.

The roots of the Solanum nigrum plant are in contact with the water body to purify the water.

The Solanum nigrum is used to treat drinking water with a concentration of cadmium ions not higher than 200 μg/L; the Solanum nigrum plant will continue to be hydroponic for 24 hours after a round of water purification treatment for 2-12 hours, and the Solanum nigrum will be Most of the absorbed metal cadmium is transported from the roots to the leaves and stems for storage, and the water purification ability is restored, which can be used for the next round of water purification treatment. Each Solanum nigrum corresponds to purifying 1-1.2 liters of cadmium-polluted water.

The treated water samples all meet the national drinking water quality standard (GB5749-85), generally lower than 3μg/L.

Treatment after the Solanum nigrum completes the circulating water purification: The cadmium absorbed by the Solanum nigrum plant can be extracted by mechanical pressing, and the extraction rate is close to 80%; the plant residue after pressing can be used for industrial wastewater treatment after drying and crushing. Heavy metal adsorption and removal.

The invention has good removal effect on trace cadmium pollution in drinking water, simple operation and wide application range, and has great application potential in drinking water purification.

The strain was isolated from Solanum nigrum plants collected near the tailings mine of Shuikoushan mining area in Hengyang, Hunan Province, and it is an endophytic bacterium of Solanum nigrum. Rinse the collected whole Solanum nigrum plant with clear water, get some roots, stems, and leaves respectively and soak them in 2% (v/v) hypochlorous acid solution for 3 minutes for surface disinfection, then rinse them in sterile water for 5 minutes. Remove residual hypochlorous acid on the plant surface for the first time. The surface-sterilized plants were ground to a paste with a sterile mortar, diluted 10-10000 times with 1% (m/v) sodium chloride, and spread on solid LB medium planes respectively, and cultivated for 48 hours. According to the difference in colony morphology, a single colony of endophytic bacteria was picked for expansion culture. After testing for heavy metal tolerance and plant growth-promoting factors, the endophytic bacteria numbered LKS03 were selected for plant inoculation. LKS03 has a high ability to produce ACC (1-aminocyclopropane-1-carboxylic acid) deaminase and IAA (indole acetic acid), and its growth is not significantly affected by the culture conditions of Cd 2mM, Zn5mM, and Pb 5mM , the strain viability is normal.

LKS03 is a Gram-positive bacterium, and the suitable growth temperature is 25-30°C, and the growth is obviously inhibited if it is higher than 38°C. After coating on solid LB medium and culturing at 30°C for 2 days, the colony diameter is 1-1.5 mm, yellow in color, smooth, raised and moist on the surface. According to the 16SrDNA sequence sequencing results of LKS03 (GenBank ID: HQ331133), combined with the analysis of colony morphology and physiological characteristics, it was shown that it was a bacterium of the genus Chryseobacterium, and it was named Chryseobacterium sp.LKS03.

Description of drawings

Fig. 1 is the simulated polluted drinking water time curve diagram that Solanum nigrum purifies different cadmium concentrations;

Fig. 2 is the water purification time curve of Solanum nigrum on the 45th day and 80 days of the culture cycle;

Fig. 3 is the comparison of Solanum nigrum inoculated with Chryseobacterium sp.LKS03 and non-inoculated Solanum nigrum water purification ability;

Fig. 4 is that the present invention has been inoculated the Solanum nigrum of Chryseobacterium sp.LKS03 continuous 4 times water purification treatment effect figure;

Fig. 5 is the impact of several metal ions on the water purification ability of Solanum nigrum inoculated with Chryseobacterium sp.LKS03 of the present invention.

Detailed ways

The following examples are intended to further illustrate the present invention, rather than limit the present invention.

Example 1

Germination of nightshade seeds, inoculation with Chryseobacterium sp.LKS03 and hydroponic culture of plants:

1. Solanum solanum seeds are soaked in 75% alcohol solution for 15 seconds to sterilize the surface, rinsed with water for 3 times, dried and used for Chryseobacterium sp.LKS03 inoculation.

2. Soak the sterilized Solanum nigrum seeds in Chryseobacterium sp.LKS03 inoculum solution for 2 hours, take them out and use them for sowing.

3. Spread the vermiculite in a tray with a thickness of about 5 cm, pour it thoroughly with 1/4 concentration of modified Hoagland's solution, and sow nightshade seeds in it. It will germinate in about 2-3 days, and the black nightshade can grow to a height of 10 cm in about 2 weeks and be transferred to hydroponics.

The improved Hoagland solution with a concentration of 4.1/4 is also used as a hydroponic nutrient solution, and the nutrient solution is changed every 5 days and replenished from time to time. After another 30 days the nightshade plants were used for water purification.

Example 2

Chryseobacterium sp.LKS03 has a high ability to produce ACC (1-aminocyclopropane-1-carboxylic acid) deaminase and IAA (indole acetic acid), which can promote the growth of plant roots. On the 45th day and the 80th day of the growth cycle, inoculated Chryseobacterium sp.LKS03 plants and plants without inoculation respectively collected 5 samples, measured root length and root weight, and the results are shown in Table 2:

Table 2

On the 45th day of the growth cycle, the root length and root weight of Solanum nigrum plants inoculated with Chryseobacterium sp.LKS03 increased by 21.8% and 25.8%, respectively; The length and root weight increased by 25.7% and 38.8%, respectively. The experimental results showed that the inoculation of Chryseobacteriumsp.LKS03 had a significant effect on the root growth of Solanum nigrum.

Example 3

Tap water was added with heavy metal ions to simulate polluted drinking water. The concentration of cadmium in the simulated polluted drinking water was 50 μg/L. The ability of inoculated nightshade and non-inoculated nightshade to purify the simulated contaminated drinking water was compared. 1 liter of simulated polluted drinking water was poured into the water tank. Solanum nigrum was fixed above the water tank, and the roots were in contact with the water body. The change of cadmium concentration in the water body was tracked and detected within 16 hours. The cadmium concentration was measured by an atomic spectrophotometer. The water purification effect is shown in the figure Shown in 3: It can be seen from the experimental results that Solanum nigrum inoculated with Chryseobacteriumsp. hours, the processing efficiency increased by nearly 33%. It can be seen that after inoculation of endophytic bacteria, the root of Solanum nigrum absorbs cadmium ions faster and the water purification efficiency is higher.

Example 4

Tap water was added with heavy metal ions to simulate polluted drinking water. The cadmium concentration in the simulated polluted drinking water was 100 μg/L, and 1 liter of simulated polluted drinking water was poured into the tank. Solanum nigrum inoculated with Chryseobacterium sp.LKS03 was fixed above the tank, and the root Contact with water body, track and detect the change of cadmium concentration in water body within 16 hours, and the cadmium concentration is measured by atomic spectrophotometer. After the purification treatment is completed, the nightshade will continue to be hydroponics, and the drinking water purification treatment will continue after 24 hours. Four consecutive cycles of drinking water purification treatment are performed, and the water purification effect is shown in Figure 4: From Figure 4, it can be seen that the continuous water purification capacity of Solanum nigrum is quite stable.

Example 5

Add heavy metal ions to tap water to simulate polluted drinking water. The concentration of cadmium is 100μg/L. At the same time, several divalent metal cations are added respectively. Mg 500mg/L, used to detect the effects of various common cations in water on the water purification ability of nightshade inoculated with Chryseobacterium sp.LKS03. Track and detect the change of cadmium concentration in the water body within 12 hours, and the cadmium concentration is measured by atomic spectrophotometer. The water purification effect is shown in Figure 5: It can be seen from Figure 5 that various metal divalent cations have little effect on the water purification of nightshade nightshade, and the scope of application of nightshade nightshade water purification is very wide.

Claims (10)

1. one kind promotes black nightshade to remove the microorganism that Trace Cadmium is polluted in the water, it is characterized in that described microorganism is golden yellow bacillus Chryseobacterium sp.LKS03, and preserving number is CCTCC NO:M 2010236.

2. application rights requires 1 described microorganism to promote black nightshade to remove the method that Trace Cadmium is polluted in the water, it is characterized in that, to in golden yellow bacillus Chryseobacterium sp.LKS03 bacterium liquid, soak 1-3 hour behind the black nightshade seed surface sterilization, take out sowing, change water planting over to after two weeks; Black nightshade plant after 30 days is used to purify waste water.

3. microorganism according to claim 2 promotes black nightshade to remove the method that Trace Cadmium is polluted in the water, it is characterized in that, described black nightshade seed soaks through 75% spirituous solution and carried out surface sterilization in 15 seconds, flushing with clean water 3 times is used for golden yellow bacillus Chryseobacterium sp.LKS03 bacterium liquid and soaks after drying.

4. microorganism according to claim 2 promotes black nightshade to remove the method that Trace Cadmium is polluted in the water, it is characterized in that, described bacterium liquid layoutprocedure is as follows: the golden yellow bacillus Chryseobacterium of picking sp.LKS03 bacterial classification inoculation enlarged culturing 12 hours to the 100ml liquid LB substratum, 4000 rev/mins centrifugal 5 minutes, remove supernatant, with the resuspended bacterium thalline of the improvement Hoagland solution of 100ml 1/4 concentration, promptly obtain bacterium liquid.

5. microorganism according to claim 2 promotes black nightshade to remove the method that Trace Cadmium is polluted in the water, it is characterized in that described sowing is that vermiculite is laid in the pallet, thickness 4-6 centimetre, improvement Hoagland solution with 1/4 concentration irrigates, and black nightshade seed is seeded in wherein.

6. microorganism according to claim 2 promotes black nightshade to remove the method that Trace Cadmium is polluted in the water, it is characterized in that, described water planting is to adopt the improvement Hoagland solution of 1/4 concentration as mill water culture nutrient solution, changes one time of nutrition liquid in 4-6 days, and constantly replenishes.

7. promote black nightshade to remove the method that Trace Cadmium is polluted in the water according to claim 2 or 4 or 5 or 6 described microorganisms, it is characterized in that the improvement Hoagland solution prescription of described 1/4 concentration is: KNO ₃125mg/L; KH ₂PO ₄35mg/L; NH ₄H ₂PO ₄20mg/L; MgSO ₄7H ₂O 125mg/L; Ca (NO ₃) ₂4H ₂O 235mg/L; FeSO ₄7H ₂O 10mg/L.

8. microorganism according to claim 2 promotes black nightshade to remove the method that Trace Cadmium is polluted in the water, it is characterized in that the time that described black nightshade plant is used to purify waste water is 30-40 days.

9. microorganism according to claim 2 promotes black nightshade to remove the method that Trace Cadmium is polluted in the water, it is characterized in that described black nightshade plant root contacts with water body purifies waste water.

10. promote black nightshade to remove the method that Trace Cadmium is polluted in the water according to claim 2 or 8 or 9 described microorganisms, it is characterized in that described black nightshade is used to handle concentration of cadmium ions for not being higher than the tap water of 200 μ g/L; After described black nightshade plant is taken turns clean water treatment in 2-12 hour through one, continue water planting and cultivated 24 hours, carry out the next round clean water treatment, the corresponding 1-1.2 that purifies of every strain black nightshade rises the water of cadmium pollution.

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