A stable anti-stress microbial community structure and a construction method and application thereof

Abstract

The application discloses a stable anti-reversibility microbial community structure and a construction method and application thereof, and relates to the technical field of microbial community construction, and in particular to a stable anti-reversibility microbial community structure and a construction method and application thereof.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically, to a stable, stress-resistant microbial community structure, its construction method, and its application. Background Technology

[0002] With the increasing severity of global eutrophication, and in line with current carbon reduction and decarbonization needs, the efficient removal of pollutants such as nitrogen and phosphorus from water bodies has become a crucial issue in wastewater treatment. As the demand for high-performance biomaterials grows in green biomanufacturing and ecological restoration, the development of live microbial preparations with high stability, strong resilience, and resource utilization has also become an important research direction. Microalgae, due to their rapid growth, high photosynthetic efficiency, and high-value biomass content, can absorb nitrogen and phosphorus from water bodies as nutrients and simultaneously fix carbon dioxide. In recent years, they have received widespread attention in water treatment and resource utilization, and are a highly promising source of natural biomaterials.

[0003] However, the cultivation of microalgae and their application in water treatment still face many technical bottlenecks, restricting their large-scale production and technological application. On the one hand, although closed photobioreactors can maintain high-density growth of pure green algae through high-temperature sterilization and pure CO2 supply, their equipment investment is large, energy consumption is high, and costs are high, making large-scale promotion difficult. While cultivating microalgae in open systems can reduce costs, direct contact with the external environment makes them susceptible to contamination by other algae, bacteria, protozoa, viruses, and other microorganisms, leading to slow growth, reduced biomass, difficulty in absorbing nutrients such as nitrogen and phosphorus from the water, and even system collapse. On the other hand, when a single pure species of microalgae is cultivated in an open system, its single ecological niche and lack of ecological buffering mechanisms make it vulnerable to shocks such as sudden temperature changes, mixed rainwater and sewage flow, or protozoan invasion, easily leading to algal community imbalance that is difficult to recover. The cultivation system is difficult to operate continuously and steadily, making it difficult to maintain stability and achieve continuous and steady-state production and preservation. Therefore, current microalgae and microalgae materials generally suffer from high cultivation costs and system instability in cultivation and water treatment applications.

[0004] To address the aforementioned issues, existing technologies primarily cultivate single or mixed algal species and apply them to the removal of nutrients such as nitrogen and phosphorus from water bodies. For example, a method and application for treating pig manure wastewater using microalgae (patent application publication number CN112125407A) involves activating a pre-cultured single algal species, Chlorella vulgaris, and inoculating it into the filtrate of pig manure wastewater. The temperature is controlled at 14-24℃ to remove nitrogen and phosphorus from the wastewater, with a removal cycle of 5-7 days. Although this method has high nitrogen and phosphorus removal efficiency, the single algal species is easily contaminated by other microorganisms during open-system cultivation, resulting in unstable cultivation. Furthermore, strict temperature control is required during cultivation, leading to high cultivation costs. To improve the stability of microalgae cultivation, a method for treating urban sewage using mixed microalgae (patent publication number CN114133039B) employs a mixed algal species, Chlorella vulgaris and Scenedesmus, for water treatment. While this method addresses the issue of single-algae cultivation being susceptible to contamination by other microorganisms in practical industrial applications, its overall nitrogen and phosphorus removal capacity is somewhat reduced, and the problem of microalgae's weak resistance to environmental changes remains unresolved. In summary, current technologies for the cultivation and application of microalgae suffer from several drawbacks, including susceptibility to contamination, limited ecological niche, difficulty in achieving continuous and stable operation, and poor product stability, weak stress resistance, and difficulty in achieving continuous steady-state production under low-cost open conditions. These shortcomings fail to meet the demands of green development and resource utilization. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a stable, stress-resistant microbial community structure, its construction method, and its applications. By constructing a stable microbial community structure dominated by green algae, containing small amounts of cyanobacteria (Microcystis), diatoms, and protozoa in an open system, the microalgal community can prevent contamination by other microorganisms and resist changes in the external environment during open cultivation, enabling long-term open cultivation and reducing the cost of microalgae cultivation. The stress-resistant microbial community of the present invention can be used to absorb nitrogen and phosphorus from water, thereby improving water quality. Simultaneously, the cultivation process generates a large amount of microalgal biomass, which, due to its rich carbon source and nitrogen and phosphorus content, can be used to enrich the soil, improve soil fertility, and achieve resource utilization.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for constructing a stable, stress-resistant microbial community structure, comprising the following steps: S1. Take green algae and protozoa in the logarithmic phase, as well as algal solution containing Microcystis, add nutrients and trace elements to form a microbial community structure dominated by green algae-Microcystis-protozoa for co-culture. When the number of green algae in the microbial community exceeds 80%, stop the culture to make green algae the dominant species. S2. After diluting the co-culture solution obtained in step S1, the solution is run in a semi-continuous flow in a photobioreactor. The water is changed periodically, and nutrients and trace elements are replenished regularly. At the same time, photosynthesis promoters are added to continuously expand the microalgal biomass and maintain the dominance of green algae. S3. During the cultivation process, when the proportion of free green algae is greater than 60% or the community is impacted, add a green algae community-aggregating agent to form a green algae community, and you will get the desired product.

[0008] As some specific embodiments of the present invention, in step S1, the algal solution containing Microcystis is obtained by taking a surface water sample from the Microcystis aggregation area in a lake, filtering it through a 100μm filter to remove large zooplankton and impurities; the density of Microcystis in the algal solution containing Microcystis is 1.2 × 10⁻⁶. 8 ~2×10 9 cells / mL.

[0009] The purpose of extracting microcystis liquid from lakes is to construct a small ecosystem, mainly composed of green algae, protozoa, and microcystis, and also rich in other diverse biological types such as diatoms and zooplankton. Such an ecosystem is stable, unaffected by environmental stresses, and can be autonomously regulated.

[0010] As some specific embodiments of the present invention, in step S1, the initial inoculation density of the green algae is 2.0 × 10⁻⁶. 7 ~3.0 × 10 8 cells / mL; the initial inoculation density of the protozoa was 3 × 10⁶ cells / mL. 2 ~5×10 3 cells / mL.

[0011] As some specific embodiments of the present invention, in step S1, the co-cultivation time is 6-8 days; the co-cultivation conditions are: temperature 20~30 ℃, light intensity 10000~100000 1x, light-dark cycle 14h~24h:10h~0h, and aeration is carried out during the light cycle.

[0012] As some specific embodiments of the present invention, in step S1, red light can be supplemented during co-culture to selectively induce thickening of the green algal cell wall. The wavelength of the red light is 600-700 nm, and the photoperiod is 14h-24h:10h-0h. In step S2, the co-culture solution obtained in step S1 is diluted to a total microbial density of 3.2 × 10⁻⁶.10 ~4×10 11 cells / mL.

[0013] During the co-culture in step S1, the algal toxins (MC-LR, etc.) continuously released by Microcystis inhibit the proliferation of zooplankton such as rotifers and cladocerans in the Microcystis algal solution. Due to the thick cell walls of green algae, protozoa preferentially feed on Microcystis, causing their numbers to decrease. Ultimately, green algae rapidly occupy the ecological niche due to their thick cell walls and strong toxin tolerance, evolving into a community dominated by green algae predated by antiprotozoa. If necessary, red light can be supplemented during the culture period to selectively induce cell wall thickening in green algae, further enhancing their resistance to protozoa and adverse conditions, and improving the survival rate of the cultured green algae.

[0014] As some specific embodiments of the present invention, in step S2, the co-culture solution obtained in step S1 is diluted to a total microbial density of 3.2 × 10⁻⁶. 10 ~4×10 11 cells / mL.

[0015] As some specific embodiments of the present invention, in step S2, the HRT (hydraulic retention time) of the semi-continuous flow operation is 2-5 days; the cultivation conditions of the semi-continuous flow operation are: temperature 20-30℃, light intensity 10000-1000001x, light-dark cycle 14h-24h:10h-0h, and aeration is implemented during the light cycle.

[0016] As some specific embodiments of the present invention, in step S1 and / or step S2, the nutrients and trace elements include 1.0~2.0 g / L sodium nitrate, 0.02~0.05 g / L dipotassium hydrogen phosphate, 0.02~0.04 g / L calcium chloride, 0.01~0.03 g / L sodium carbonate, 1.5~3.8 g / L boric acid, 1.5~2.5 g / L manganese chloride, 0.15~0.3 g / L zinc sulfate, 0.05~0.10 g / L copper sulfate, and 0.25~0.50 g / L sodium molybdate.

[0017] As some specific embodiments of the present invention, in step S2, the amount of photosynthesis promoter added each time is 0.02-4‰, and the photosynthesis promoter includes sodium bicarbonate, ferric chloride, citric acid and urea in a mass ratio of 10-20:1-3:2-6:5-15.

[0018] Step S2 involves daily quantitative water exchange to remove free zooplankton and reduce their residence time, thereby inhibiting the proliferation of predators such as rotifers and cladocerans. During this process, nutrients and trace elements are periodically replenished, along with the addition of 0.02-4‰ (w / w) of photosynthesis promoters to continuously expand microalgal biomass and maintain the dominance of green algae. The microalgal community in photoreactor A is dominated by green algae, but also includes small amounts of other microorganisms such as cyanobacteria, diatoms, and protozoa.

[0019] As some specific embodiments of the present invention, in step S3, the addition ratio of the green algae community aggregation agent is 5-10‰, and the green algae community aggregation agent includes chitosan, calcium chloride and sodium alginate in a mass ratio of 2-4:1-2:1-3.

[0020] As some specific embodiments of the present invention, in step S3, during the semi-continuous flow operation, the algal solution in photoreactor A is examined under a microscope every 10-20 days. When the number of free green algae is >60%, 5-10‰ of a green algae community-aggregating agent is added immediately to promote the formation of green algae communities and prevent rotifers attached to the photoreactor wall from preying on the microalgae. If there is a sudden change in temperature, mixed rainwater and sewage flow, or protozoan invasion, a green algae community-aggregating agent is added once after the impact to alleviate the impact.

[0021] Secondly, the present invention provides a stable stress-resistant microbial community structure, which is prepared by any of the preparation methods described above.

[0022] As some specific embodiments of the present invention, the stress-resistant microbial community structure includes: (a) Photosynthetic microorganisms, including green algae and microcystis, wherein the green algae are the dominant species and the number of green algae cells existing in a colony form accounts for more than 60% of the total number of green algae cells, and the green algae include at least one of Chlorella and Scenedesmus. (b) Protozoa, including at least one of flagellates, ciliates and sarcoptera.

[0023] As some specific embodiments of the present invention, the green algae account for 80-90% of the number of microbial communities, the microcystis accounts for 2-8% of the number of microbial communities, and the protozoa account for 1.5-3% of the number of microbial communities.

[0024] As some specific embodiments of the present invention, the photosynthetic microorganisms also include groups such as diatoms and cryptophytes.

[0025] Thirdly, the present invention provides an application of a stable, stress-resistant microbial community structure as described in any of the preceding claims in wastewater treatment or water body remediation.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1) This invention solves the problems of microalgae being susceptible to microbial contamination, unstable culture system, and weak system resistance to shocks during open culture. The microbial community structure constructed by this invention with green algae as the dominant species has strong stability and has the advantages of preventing contamination by miscellaneous bacteria, preventing protozoan feeding, and high resistance to external shocks. This allows the system to maintain a high biomass and strong nitrogen and phosphorus assimilation capacity under open culture, thereby reducing the cost of microalgae culture.

[0027] 2) The microbial community structure constructed by this invention can be fully applied to the water purification of sewage treatment plant effluent, aquaculture wastewater, etc.; the large number of microalgae produced during the cultivation process contain rich carbon sources and nitrogen and phosphorus, which can be used to improve soil fertility and realize resource utilization.

[0028] 3) This invention constructs a balanced ecosystem dominated by green algae, microcystis, and protozoa, exhibiting excellent stability. Microcystis continuously releases microcystin, effectively inhibiting contamination from predatory organisms (such as rotifers and cladocerans). Simultaneously, the selective feeding of protozoa on microcystis and the community structure formed by the green algae themselves combine to create a strong resistance to biological predation and environmental shocks, maintaining stable composition and high biological activity for extended periods even in open or semi-open environments.

[0029] 4) The microbial community structure formed by this invention has a high efficiency of assimilation and fixation, and can be used directly as a water purification material for the deep treatment of sewage treatment plant effluent, aquaculture wastewater, etc., continuously assimilating pollutants such as nitrogen and phosphorus; and as a high-value biological resource material, the large amount of microalgal biomass accumulated during operation contains rich carbon, nitrogen, phosphorus and organic matter, which can be used as a high-quality soil amendment material or a precursor for bio-fertilizer, realizing the synchronization of pollution control and resource recovery, and greatly enhancing the comprehensive value and market competitiveness. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0031] Example 1: Construction of a stress-resistant microalgal community structure 1. Take 5L of BG11 liquid culture medium and add it at 2.0×10⁻⁶. 8 Chlorella (a green algae) in its logarithmic growth phase was inoculated at a density of 4.0 × 10⁶ cells / mL. 3Flagellates in the logarithmic growth phase were inoculated at a density of cells / mL. One L of lake water was taken from the surface water of the Microcystis agglomerate area in Dianshan Lake and filtered through a 100 μm filter to remove large zooplankton and impurities, yielding an algal solution containing Microcystis agglomerates (cyanobacteria), with a Microcystis agglomerate density of 1.2 × 10⁻⁶ cells / mL. 8 The algal culture was transferred to a culture medium containing the following nutrients and trace elements: sodium nitrate 1.5 g / L, dipotassium hydrogen phosphate 0.04 g / L, calcium chloride 0.036 g / L, sodium carbonate 0.02 g / L, boric acid 2.86 g / L, manganese chloride 1.86 g / L, zinc sulfate 0.22 g / L, copper sulfate 0.08 g / L, and sodium molybdate 0.39 g / L. This resulted in a microalgal community dominated by Microcystis aeruginosa, Chlorella vulgaris, and flagellates. The culture was conducted at 25 ℃, with a light intensity of 50,000-70,000 lx, a light-dark cycle of 14 h:10 h, and aeration. On day 7, microscopic examination of the algal culture revealed that green algae comprised 85% of the culture. At this point, the culture was stopped, and green algae became the dominant species in the system.

[0032] 2. After cultivation, transfer the algal solution to a 25 L photoreactor A, and dilute the algal solution with water to a final volume of 25 L. At this point, the total algal density is 3.6 × 10⁻⁶. 11 The initial abundance and proportion of the microbial community structure obtained by microscopic examination of the samples were as follows: green algae accounted for approximately 85%, with an abundance of 3.06 × 10⁶ cells / mL. 11 cells / mL; Microcystis content was approximately 6%, with an abundance of 2.16 × 10⁻⁶. 10 cells / mL; protozoan content was approximately 3%, with flagellates having an abundance of 7.5 × 10⁻⁶. 9 The abundance of ciliates was 3.3 × 10⁶ cells / mL. 9 cells / mL.

[0033] Photoreactor A was set at a temperature of 28 ℃, a light intensity of 50,000-70,000 lx, and a light-dark cycle of 14 h:10 h, with aeration implemented during the photocycle. The system operated in a semi-continuous flow, with a HRT of 4 days. During this period, nutrients and trace elements were replenished regularly, and a 2‰ photosynthesis promoter was added periodically. Every 15 days during operation, algal samples were taken from photoreactor A for microscopic examination. When the number of free green algae exceeded 60%, an 8‰ green algae colony-aggregating agent was immediately added to obtain a stress-resistant microbial community structure.

[0034] The photosynthesis promoters include sodium bicarbonate, ferric chloride, citric acid, and urea in a mass ratio of 16:2:4:11.

[0035] The green algae community building agent includes chitosan, calcium chloride, and sodium alginate in a mass ratio of 3:1.5:2.

[0036] 3. Photoreactor A operated continuously for one year, establishing a stable microbial community dominated by Chlorella, with a stable chlorophyll content of 12000 μg / L, pH of 12.0, and Fv / Fm of 0.62. Within this stable microbial community, green algae comprised approximately 90% of the community, with an abundance of 3.2 × 10⁻⁶. 10 cells / mL; Microcystis content was approximately 5%, with an abundance of 1.8 × 10⁻⁶. 9 The cell count was approximately 1.5%; it also contained a small number of protozoa, with flagellates accounting for 1.2 × 10⁻⁶. 5 The abundance of ciliates was 3.0 × 10⁶ cells / mL. 4 cells / mL.

[0037] Therefore, after one year of operation, the microbial community structure can still maintain stability, and the proportion of each microorganism in the community is still within the ideal range.

[0038] Example 2: Cultivation of microalgal communities in an open environment The algal solution obtained in photoreactor A in step 2 of Example 1 was transferred to a white open culture tank with a height of 35 cm and a total volume of 60 L. It was then cultured outdoors in an open environment with an algal solution volume of 45 L. An aeration device was connected, with aeration time from 8:00 to 20:00. Nutrients and trace elements were added regularly. 2‰ photosynthesis promoter and 8‰ green algae colony-building agent were added weekly. The system was operated in a semi-continuous flow, with the HRT (Heat-Resistance Time) adjusted flexibly according to environmental conditions, ranging from 2 to 4 days, for a continuous operation for one year. The chlorophyll content of the microalgae fluctuated between 8000 and 15000 μg / L year-round, the pH ranged from 9.3 to 12.5, and the Fv / Fm ratio was 0.42 to 0.62. Under open environmental conditions, the microalgae exhibited strong resistance to changes in environmental factors and could rapidly recover growth when stress was reduced. Under high temperature (>38℃) conditions, with an HRT of 2.5 days, the chlorophyll content of microalgae remained stable at 11000 μg / L, pH was 10.8, and Fv / Fm was 0.48. When the temperature decreased slightly, the microalgae resumed photosynthesis, Fv / Fm increased to 0.58, the chlorophyll content increased to 13500 μg / L, and the pH increased to 11.4. Under low temperature (<10℃) conditions, with an HRT of 4 days, the chlorophyll content of microalgae remained stable at 9000 μg / L, pH was 9.5, and Fv / Fm was 0.42. When the temperature increased, the photosynthesis of microalgae was enhanced, Fv / Fm increased to 0.50, the chlorophyll content increased to 11200 μg / L, and the pH increased to 10.2.

[0039] Therefore, in an open environment, the microbial community structure of this invention can still maintain long-term stability and extreme resistance.

[0040] Example 3: Purification Experiment of Livestock and Poultry Farming Wastewater by Microalgae The concentration of inorganic nitrogen (nitrate nitrogen, ammonia nitrogen) in the effluent of a certain livestock and poultry breeding wastewater is about 60 mg / L, and the concentration of phosphate is about 6 mg / L. The stress-resistant microalgal community obtained in step 2 of Example 1 was inoculated into 45L of livestock and poultry breeding wastewater at a concentration of 0.70 g / L dry weight. It was cultured in a semi-continuous flow under natural light (20,000-40,000 lx per day, with a diurnal rhythm of about 14 h:10 h), ambient temperature (fluctuating between 30-40℃), and aeration by an aeration device (aeration time 8:00-20:00). The HRT was 4 days, and the system was run continuously for 20 days. After an adaptation period of 2-3 days, the nitrogen and phosphorus concentrations in the effluent basically met the requirements of the Class V functional water quality standard in the "Surface Water Environmental Quality Standard (GB3838-2002)". The inorganic nitrogen was 0.04-0.15 mg / L (removal rate of 99%), and the phosphate was 0.13-0.2 mg / L (removal rate of 85-90%). The microalgae steadily increased by 0.20 g / L dry weight per day, which was greater than the daily content of algae in the effluent, and no recirculation was required. On the 10th day of reactor operation, a high temperature of 45°C was encountered. At this time, 4‰ photosynthesis promoter and 10‰ green algae colony-forming agent were added. The daily increase in microalgae dry weight remained at 0.10 g / L, and the removal rate of inorganic nitrogen and phosphate in the water remained at 64-72% and 79-82%, respectively. On the 12th day, as the temperature dropped to 38°C, the daily increase in microalgae dry weight recovered to 0.15 g / L, and the removal rate of inorganic nitrogen and phosphate in the water was 85-91% and 86-90%, respectively.

[0041] Comparative Example 1 Compared with Example 1, the difference is that the inoculation density of green algae in the co-culture stage was reduced to 1.0 × 10⁻⁶. 7 cells / mL, Microcystis density increased to 5.0 × 10⁶. 8 The cell / mL ratio was maintained, and the protozoan density remained constant. Culture was stopped when the green algae count reached 65%. At this point, the volume percentages of green algae, Microcystis, and protozoa in the microbial community were 65%, 30%, and 5%, respectively, with free green algae accounting for 45% (<60%) of the total green algal cell count. Following Example 2, an open-environment culture experiment was conducted. The results showed that from the third day of operation in the open environment, the proportion of green algal cells continuously decreased, indicating poor resistance and slow recovery after exposure to temperature or rain / pollution shocks. By the seventh day, the chlorophyll content in the algal solution decreased from 11000 μg / L to 5000 μg / L, the Fv / Fm ratio decreased from 0.60 to 0.28, the pH could not be maintained above 9.0, microalgae could not grow normally, and the system severely collapsed.

[0042] Comparative Example 2 Compared to Example 1, the difference lies in that the initial inoculation density of green algae was increased to 3.0 × 10⁻⁶ in the co-cultivation stage of step 1. 8 cells / mL, Microcystis density increased to 5.0 × 10⁶. 7 cells / mL, protozoan density decreased to 1.0 × 10⁻⁶. 3 The culture was stopped when the proportion of green algae reached 95%, at which point the proportions of green algae, Microcystis, and protozoa in the microbial community were 95%, 4%, and 1%, respectively. Following Example 2, an open-environment culture experiment was conducted. The results showed that the system operated stably for the first 10 days, with chlorophyll in the algal solution slowly increasing from 7000 μg / L to 9000 μg / L. Due to the low content of Microcystis in the system, the released algal toxins had a weak inhibitory effect on zooplankton, and zooplankton continued to grow. By day 11, cladocerans and rotifers rapidly increased, and the chlorophyll content in the algal solution showed a decreasing trend. After a 38°C heat shock on day 12, a protozoan outbreak occurred, and chlorophyll dropped from 8000 μg / L to 3000 μg / L within 3 days. The Fv / Fm ratio fell from 0.60 to 0.25, and the system failed to recover to pre-shock levels after 18 days.

[0043] Comparative Example 3 The single *Chlorella vulgaris* scheme from patent application publication number CN112125407A was used as a control group. The microbial community structure obtained in step 2 of Example 1 was compared with that obtained under the same conditions of 10% pig manure wastewater, natural light, and 14-24℃. In the single-algae group, rotifers and cladocerans proliferated to 4.2 × 10⁻⁶ starting from day 8. 4 The number of cells / mL decreased, chlorophyll dropped from 11000 μg / L to 2800 μg / L, Fv / Fm decreased from 0.60 to 0.25, and ammonia nitrogen removal rate decreased from 98% to 34%. The system collapsed on the 15th day and needed to be resterilized. In contrast, the zooplankton in the microbial community structure of Example 1 was consistently <2×10⁻⁶. 3 The microbial community structure constructed in this invention exhibits significantly better long-term open stability than single microalgae, with chlorophyll content maintained at 10,000-13,000 μg / L, Fv / Fm stable at 0.55-0.62, and ammonia nitrogen and total phosphorus removal rates >90% with no degradation after 30 days of continuous operation.

[0044] Comparative Example 4 According to the mixed culture scheme of Chlorella and Scenedesmus in patent publication number CN114133039B, the microbial community structure obtained in step 2 of Example 1 was subjected to temperature shock test under the same conditions: for the same wastewater treatment plant effluent, after the temperature rose to 38°C, the Fv / Fm of the mixed algae group dropped from 0.58 to 0.32, the chlorophyll loss was 62%, and the ammonia nitrogen removal rate dropped from 82% to 38%. It took 12 days and the addition of microalgae for the system to recover. However, the Fv / Fm of the microbial community structure in Example 1 dropped from 0.58 to 0.48 and recovered to 0.52 after 48 hours, and the ammonia nitrogen removal rate was always >88%. This proves that the microbial community structure constructed by the present invention is significantly better than the Chlorella and Scenedesmus mixed scheme in terms of resistance to temperature shock.

[0045] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for constructing a stable, stress-resistant microbial community structure, characterized in that, Includes the following steps: S1. Take green algae and protozoa in the logarithmic phase, as well as algal solution containing Microcystis, add nutrients and trace elements to form a microbial community dominated by green algae-Microcystis-protozoa for co-culture. When the number of green algae in the microbial community exceeds 80%, stop the culture to make green algae the dominant species. S2. After diluting the co-culture solution obtained in step S1, the solution is run in a semi-continuous flow in a photobioreactor. The water is changed periodically, and nutrients and trace elements are replenished regularly. At the same time, photosynthesis promoters are added to continuously expand the microalgal biomass and maintain the dominance of green algae. S3. During the cultivation process, when the proportion of free green algae is greater than 60% or the community is impacted, add a green algae community-aggregating agent to form a green algae community, and you will get the desired product.

2. The preparation method according to claim 1, characterized in that, In step S1, the algal solution containing Microcystis is obtained by taking a surface water sample from the Microcystis aggregation area in a lake, filtering it through a 100μm filter to remove large zooplankton and impurities; the density of Microcystis in the algal solution is 1.2 × 10⁻⁶. 8 ~2×10 9 cells / mL; And / or, in step S1, the initial inoculation density of the green algae is 2.0 × 10⁻⁶. 7 ~3.0 × 10 8 cells / mL; the initial inoculation density of the protozoa was 3 × 10⁶ cells / mL. 2 ~5×10 3 cells / mL.

3. The preparation method according to claim 1, characterized in that, In step S1, the co-cultivation time is 6-8 days; the co-cultivation conditions are: temperature 20-30 ℃, light intensity 10000-100000 1x, light-dark cycle 14h-24h:10h-0h, and aeration is carried out during the light cycle. And / or, red light may be supplemented during co-cultivation, wherein the wavelength of the red light is 600-700 nm and the illumination period is 14h~24h:10h~0h.

4. The preparation method according to claim 1, characterized in that, In step S2, the co-culture medium obtained in step S1 is diluted to a total microbial density of 3.2 × 10⁻⁶. 10 ~4×10 11 cells / mL; And / or, the HRT time of the semi-continuous flow operation is 2-5 days; the culture conditions of the semi-continuous flow operation are: temperature 20-30℃, light intensity 10000-100000 1x, light-dark cycle 14h-24h:10h-0h, and aeration is implemented during the light cycle.

5. The preparation method according to claim 1, characterized in that, In step S1 and / or step S2, the nutrients and trace elements include 1.0~2.0 g / L sodium nitrate, 0.02~0.05 g / L dipotassium hydrogen phosphate, 0.02~0.04 g / L calcium chloride, 0.01~0.03 g / L sodium carbonate, 1.5~3.8 g / L boric acid, 1.5~2.5 g / L manganese chloride, 0.15~0.3 g / L zinc sulfate, 0.05~0.10 g / L copper sulfate, and 0.25~0.50 g / L sodium molybdate; And / or, in step S2, the amount of photosynthesis promoter added each time is 0.02-4‰, and the photosynthesis promoter includes sodium bicarbonate, ferric chloride, citric acid and urea in a mass ratio of 10-20:1-3:2-6:5-15.

6. The preparation method according to claim 1, characterized in that, In step S3, the addition ratio of the green algae community aggregation agent is 5-10‰, and the green algae community aggregation agent includes chitosan, calcium chloride and sodium alginate in a mass ratio of 2-4:1-2:1-3.

7. A stable, stress-resistant microbial community structure, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

8. The stress-resistant microbial community structure according to claim 7, characterized in that, include: (a) Photosynthetic microorganisms, including green algae and microcystis, wherein the green algae are the dominant species and the number of green algae cells existing in a colony form accounts for more than 60% of the total number of green algae cells, and the green algae include at least one of Chlorella and Scenedesmus. (b) Protozoa, including at least one of flagellates, ciliates and sarcoptera.

9. The stress-resistant microbial community structure according to claim 8, characterized in that, The green algae constitute 80-90% of the microbial community, the microcystis constitutes 2-8% of the microbial community, and the protozoa constitute 1.5-3% of the microbial community. And / or, the photosynthetic microorganisms also include diatoms and cryptophytes.

10. The application of a stable, stress-resistant microbial community structure as described in any one of claims 7-9 in wastewater treatment or water body remediation.