A Saccharothricin Bacterium NBAL-S001 and Its Application

Abstract

The present invention discloses a strain of Saccharothrix violaceirubra NBAL-S001 and its application. The Saccharothrix NBAL-S001 of the present invention is isolated from soil, and its fermentation liquid can inhibit the photosynthesis of harmful algae blooms - Microcystis aeruginosa, and has a very high algae-dissolving effect, with a 5-day algae-dissolving rate of up to 97%. The Saccharothrix NBAL-S001 of the present invention is a biological control strain with potential development and application value in preventing and controlling cyanobacterial blooms.

Description

Technical Field

[0001] The invention belongs to the technical field of microbiology, and specifically relates to a Saccharothrix violaceirubra NBAL-S001 and an application thereof. Background Art

[0002] Microcystis aeruginosa is a typical cyanobacteria, widely distributed in freshwater areas. Driven by eutrophication of water bodies, Microcystis aeruginosa proliferates abnormally, causing cyanobacterial blooms. Frequent outbreaks of algae blooms not only damage the ecological environment of water bodies, but also cause odor in water bodies and excessive levels of algae toxins, seriously threatening the safety of drinking water for residents. Therefore, how to effectively prevent and control cyanobacterial blooms has become an urgent problem to be solved in my country.

[0003] From the perspective of the causes of eutrophication of water bodies, the control of point source pollution and non-point source pollution in water bodies can effectively prevent and control the occurrence of harmful blue-green algae blooms, but it is costly and has slow results. At the same time, traditional physical and chemical methods of controlling algae blooms, such as mechanical algae removal with flocculants or the use of heavy metal salts, herbicides and other chemical substances to poison algae, have the disadvantages of high cost, poor selectivity and easy secondary pollution to the environment. Control methods that are both economical, efficient and environmentally friendly are an important need for the prevention and control of harmful blue-green algae blooms.

[0004] Bacteria play an important role in the natural extinction of water blooms and can accelerate the collapse of algal communities in water blooms. This characteristic of bacteria provides a new idea for the management of harmful cyanobacteria blooms. Algicidal bacteria are a type of bacteria that can kill or inhibit the growth of algae. They destroy the structure of algal cells and affect the physiological state of algal cells in direct or indirect ways. Direct algicidal bacteria directly contact the surface of algal cells or even invade algal cells, causing the algal body to lyse and die. The bacteria of this type of bacteria usually have a special structure that allows them to quickly approach algal cells and adsorb on the cell surface or invade the inside of the cell. For example, the genus Helicobacterium relies on the swinging of cilia to approach the algal body, and actively approaches the Chaetoceros cells through microtubule-like structures and invades the inside of the algal cells to kill the algae. However, bacteria that directly dissolve algae have natural limitations in application. The probability of their contact with microalgae is related to the number of microalgae. Therefore, it is difficult to effectively kill algal cells in the early stage of water blooms with low microalgae biomass. Indirect algicidal bacteria mainly kill algae through secreted extracellular algicidal active substances, such as antibiotics, haman alkali, pigments, nitrogen-containing compounds, proteins, etc. Algicidal substances can destroy cell structures by changing the permeability of algal plasma membranes and hydrolyzing cell walls; they can limit photosynthesis of algal cells by destroying photosynthetic pigments and inhibiting the expression of key photosynthetic genes; they can also affect the antioxidant system of algal cells and induce cell death. Algicidal substances separated and purified from the fermentation products of nematodes, such as tryptophan, tryptamine and lysine, are more stable and have stronger algicidal power against cyanobacteria than copper sulfate, and have the potential to replace chemical bloom control methods.

[0005] Algicidal bacteria mainly come from Thermus, Firmicutes, Actinobacteria, Bacteroidetes and Proteobacteria. Among them, actinomycetes are known for their ability to produce a variety of novel structural and highly active secondary metabolites. About half of the physiologically active microbial secondary metabolites discovered so far come from actinomycetes, making actinomycetes a potential microbial resource for studying algicidal active substances. At present, the technology of using the rare actinomycete Saccharothrips to control harmful cyanobacterial blooms has not been reported. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a strain of Saccharothrix violaceirubra

[0007] NBAL-S001 and its applications.

[0008] The first object of the present invention is to provide a strain of Saccharothrix violaceirubra NBAL-S001, whose deposit number is CCTCC NO: M 20241734.

[0009] The second object of the present invention is to provide the use of the Saccharotrichum NBAL-S001 in preventing and controlling harmful cyanobacteria blooms.

[0010] Preferably, the cyanobacteria is Microcystis aeruginosa.

[0011] Preferably, the application comprises the step of applying the live bacterial culture of Saccharothrix NBAL-S001 and / or the effective active substance of the live bacterial culture of Saccharothrix NBAL-S001.

[0012] Preferably, the live bacterial culture containing the Saccharothrix NBAL-S001 is the fermentation broth or supernatant of Saccharothrix NBAL-S001.

[0013] The third object of the present invention is to provide a biocontrol agent for preventing and controlling harmful cyanobacteria blooms, which contains the live bacterial culture of the Saccharotrichum NBAL-S001 and / or contains the effective active substances in the live bacterial culture of the Saccharotrichum NBAL-S001.

[0014] Beneficial effects of the present invention:

[0015] 1. The live bacterial culture of Saccharotrichum NBAL-S001 of the present invention has a highly efficient algae-lysing function on the harmful algae bloom-Microcystis aeruginosa, and the culture method is simple.

[0016] 2. The Saccharothricin NBAL-S001 of the present invention is a microbial control strain with potential application value in the prevention and treatment of harmful cyanobacterial blooms. It can be developed into a microbial algae killer, providing technical support for the green prevention and control of harmful cyanobacterial blooms, and has good application prospects.

[0017] Collection Instructions

[0018] The Saccharothrix violaceirubra NBAL-S001 of the present invention was deposited in the China Center for Type Culture Collection on August 2, 2024, classified and named Saccharothrix violaceirubra, with a collection number of CCTCC NO: M20241734, and the collection address is Wuhan University, Wuhan, China. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The colony morphology and phylogenetic tree of Saccharothrix NBAL-S001. (A) The front morphology of the colony of Saccharothrix NBAL-S001 cultured on MS medium on the 7th day and the local magnification; (B) The phylogenetic tree of Saccharothrix NBAL-S001 constructed based on the 16S rDNA sequence.

[0020] Figure 2The algae-dissolving effect of the fermentation liquid of Saccharotrichum NBAL-S001. (A) During the experiment, the chlorophyll a (Chla, ug mL -1 )(red, +NBAL-S001 fermentation broth; black, +ddH2O; blue, +fermentation medium) and (B) changes in the algalysis rate (%) of NBAL-S001 fermentation broth over time. The gray part in the figure represents the dark phase of the photoperiod, the data points are the original data (n=3), the solid line is the predicted value of the generalized additive model (GAMs), and the shaded area is the 95% confidence interval.

[0021] Figure 3 The changes of relevant parameters of the photosystem II (PSII) of Microcystis aeruginosa over time under different treatments (red, + NBAL-S001 fermentation liquid; blue, + fermentation medium, as control). (A, C, E) are the maximum fluorescence efficiency (F) of PSII, respectively. v / F m ), oxygen-releasing complex activity (W k ) and the number of reaction centers per unit PSII light-harvesting cross section (RC / CS o ) changes over time; (B, D, F) represent the changes in the magnitude of the effect of NBAL-S001 fermentation broth on the corresponding parameters over time. The gray part in the figure represents the dark phase of the photoperiod, the data points are the original data (n=3), the solid line is the predicted value of the generalized additive model (GAMs), and the shadow is the 95% confidence interval. In B, D, and F, when the 95% confidence interval does not overlap with the dashed line parallel to the x-axis, it indicates that NBAL-S001 fermentation broth has a significant effect on the corresponding parameters.

[0022] Figure 4 The specific energy flux of the reaction center of the photosystem II (PSII) of Microcystis aeruginosa under different treatments (red, + NBAL-S001 fermentation broth; blue, + fermentation medium, as control) changes over time. (A, C, E) are the light energy absorbed by the PSII unit reaction center (ABS / RC), the energy captured (TR o / RC), energy used for electron transfer after capture (ET o / RC) and the energy dissipated by heat (DI o / RC) changes over time; (B, D, F) are the changes in the magnitude of the effect of NBAL-S001 fermentation broth on the corresponding parameters over time. The gray part in the figure represents the dark phase of the photoperiod, the data points are the original data (n=3), the solid line is the predicted value of the generalized additive model (GAMs), and the shadow is the 95% confidence interval. In B, D, and F, when the 95% confidence interval does not overlap with the dotted line parallel to the x-axis, it indicates that NBAL-S001 fermentation broth has a significant effect on the corresponding parameters.

[0023] Figure 5 The changes of parameters related to energy transfer between photosystems of Microcystis aeruginosa over time under different treatments (red, + NBAL-S001 fermentation broth; blue, + fermentation medium, as control). (A, C, E) are the photosystem interstitial quinone electron acceptor Q A The reduction rate (M o ), electron transfer to Q A -The probability after (ψ Eo ) and electron transfer quantum efficiency (B, D, F) are the changes in the magnitude of the effect of NBAL-S001 fermentation broth on the corresponding parameters over time. The gray part in the figure represents the dark phase of the photoperiod, the data points are the original data (n=3), the solid line is the predicted value of the generalized additive model (GAMs), and the shadow is the 95% confidence interval. In B, D, and F, when the 95% confidence interval does not overlap with the dashed line parallel to the x-axis, it indicates that NBAL-S001 fermentation broth has a significant effect on the corresponding parameters.

[0024] Figure 6 The changes of the parameters related to the photosystem I (PSI) of Microcystis aeruginosa over time under different treatments (red, + NBAL-S001 fermentation broth; blue, + fermentation medium, as control). (A, C, E) are the electron transfer by the plastoquinone electron acceptor Q A The probability of reaching PSI (ψ RE1o ), PSI acceptor side electron transfer efficiency and the probability of electron transfer from the intersystem to the PSI acceptor side (δ Ro ) changes over time; (B, D, F) are the effects of NBAL-S001 fermentation broth on the corresponding parameters. The gray part in the figure represents the dark phase of the photoperiod, the data points are the original data (n=3), the solid line is the predicted value of the generalized additive model (GAMs), and the shadow is the 95% confidence interval. In B, D, and F, when the 95% confidence interval does not overlap with the dashed line parallel to the x-axis, it indicates that NBAL-S001 fermentation broth has a significant effect on the corresponding parameters.

[0025] Figure 7 The effect of Saccharothricin NBAL-S001 fermentation broth on the biomass of Microcystis aeruginosa (Chla, day 5 of the experiment) under different light treatments. The light conditions in the experiment were set at 80 μmol photons m -2 s -1 (light:dark, 16:8, h:h) and complete darkness. In the figure, Control and Culture were treated with fermentation medium and Saccharothricin NBAL-S001 fermentation broth, respectively.

[0026] Figure 8The algicidal effects of different components of the fermentation broth of Saccharotrichum NBAL-S001 on Microcystis aeruginosa. In the figure, Control, Culture, Cell, Broken cell and Supernatant are respectively added fermentation medium (as a control), fermentation broth, bacterial suspension, broken bacterial suspension and fermentation broth supernatant treatment.

[0027] Fig. 9 The sensitivity of the effective active ingredients in the supernatant of the fermentation broth of Saccharotrichum NBAL-S001 to temperature (A) and pH (B). DETAILED DESCRIPTION

[0028] The following examples are provided to further illustrate the present invention, rather than to limit the present invention.

[0029] Example 1: Isolation and identification of Saccharothrix NBAL-S001

[0030] 1. Isolation of strain NBAL-S001

[0031] Collect 5-10cm deep soil near the shore of Nanhu Lake in Wuhan, Hubei Province, add 10g of soil to a conical flask of 90mL sterile water, shake it for 10 minutes and dilute it 1000 times. Take 100uL and apply it on a mannitol soybean powder (MS) medium plate (mannitol 25g / L, soybean powder 25g / L, agar 20g / L, the balance is water), and nalidixic acid (20μg / mL) and actinomycin (100μg / mL) are additionally added to the MS medium to inhibit the growth of other bacteria. The plate is placed under 30°C and cultured. After a single colony grows, a single colony is immediately picked for purification, and a strain numbered NBAL-S001 is obtained according to the colony morphology. The single colony after screening and purification is then placed in a glycerol aqueous solution with a volume fraction of 25%, and stored at -80°C for standby use.

[0032] 2. Morphological and molecular biological identification of strain NBAL-S001

[0033] After the strain NBAL-S001 was cultured on the MS medium plate for 7 days, a single colony was picked. The front morphology of the colony was as follows: Figure 1 A. DNA was extracted according to the instructions of the FastPure bacteria DNA isolation Kit to obtain the genomic DNA of strain NBAL-S001. The universal primer 27F

[0034] The rDNA sequences were amplified by PCR using 1492R (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-GGTTACCTTGTTACGACTT-3'). The amplified products were detected by 1% (W / V) agarose gel electrophoresis and sent to Sangon Biotech (Wuhan) Co., Ltd. for sequencing. The 16S rRNA gene sequences obtained by sequencing were searched in the NCBI database using the BLAST program, and a phylogenetic tree was constructed using the MEGA11 software. The phylogenetic tree is shown in Figure 1 B.

[0035] The strain NBAL-S001 and Saccharothrix violaceirubra subsp. were clustered in the same branch. Combined with the morphological characteristics, the strain NBAL-S001 was identified as Saccharothrix violaceirubra ( Figure 1 ). Therefore, the strain NBAL-S001 was named Saccharothrix violaceirubra NBAL-S001 (Sugar Tricholoma NBAL-S001). The strain was sent to the China Center for Type Culture Collection on August 2, 2024, and was classified and named Saccharothrix violaceirubra. The collection number is CCTCC NO: M 20241734, and the collection address is Wuhan University, Wuhan, China.

[0036] Example 2: Algicidal effect and algicidal mechanism of Saccharotrichum NBAL-S001 on water bloom cyanobacteria - Microcystis aeruginosa

[0037] 1. Liquid fermentation of Saccharothricin NBAL-S001

[0038] NBAL-S001 was cultured on MS medium plates for 7 days (30°C), and then a single colony was taken in MS liquid medium and cultured at 30°C and 220 rpm for 2 days. MS :V 发酵 ) was inoculated into fermentation medium (each liter of fermentation medium contained: 5 g glucose, 40 g soluble starch, 15 g corn flour, 25 g soybean cake powder, 2 g peptone, 0.5 g ammonium sulfate, and the balance was deionized water) and cultured for 7 days (30°C, 220 rpm).

[0039] 2. Microcystis aeruginosa acclimation

[0040] Microcystis aeruginosa PCC7806 was provided by the Marine Microorganisms Conservation Center of Xiamen University and cultured in BG11 medium (each liter of BG11 medium contains: NaNO3 1500 mg, K2HPO4.3H2O 40 mg, MgSO4.7H2O 75 mg, CaCl2.2H2O 36 mg, ammonium ferric citrate 6 mg, EDTA 1 mg, NaCO3 20 mg, H3BO3 2.86 mg, MnCl2.4H2O 1.81 mg, ZnSO4.7H2O 0.222 mg, CuSO4.5H2O 0.079 mg, NaMoO4.2H2O 0.39 mg, Co(NO3)2.6H2O 0.0494 mg). The acclimatization environment is: temperature 28 °C, light intensity 80 μmol photons m -2 s -1 , light-dark cycle 8:16 (h:h).

[0041] 3. Determination of algae-lysing activity of Saccharotrichum NBAL-S001 fermentation broth

[0042] 1.5:100(V 发酵液 :V 藻液 ) was added to the fermentation liquid of Saccharothrix NBAL-S001 in the Microcystis aeruginosa liquid cultured in a conical flask, and the conical flask was placed at 28°C and 80 μmol photons m -2 s -1 The culture was carried out under the conditions of 1:1 ratio and 8:16 (h:h), and the cells were shaken three times a day to prevent the algal cells from settling. At the same time, sterile ddH2O and fermentation medium equal to the fermentation broth were added as blank control group and control treatment group respectively.

[0043] The biomass of Microcystis aeruginosa was expressed by the concentration of chlorophyll a (Chl a). 2 mL of water samples were taken at the 4th, 12th, 24th, 30th, 36th, 48th, 57th, 72nd, 96th, and 120th hours of the experiment. The samples were centrifuged (10 min, 10000 rpm) and the supernatant was removed and stored in a dark environment at 4 ° C until the measurement. The samples were extracted with 100% methanol in the dark at 4 ° C (24 h), and the supernatant was obtained by centrifugation (10 min, 10000 rpm). The absorbance of the supernatant at 652 nm, 665 nm, and 750 nm was measured using an ELISA reader. 652 , A 665 and A 750 ).

[0044] The concentration of Chl a was calculated by the following formula:

[0045] Chl a(μg mL-1 )=16.29×(A 665 -A 750 )–8.54×(A 652 –A 750 )

[0046] The algicidal ratio is calculated by the following formula:

[0047]

[0048] Among them, Chl a T With Chl a C Represents the chlorophyll concentration of the fermentation liquid and fermentation medium of Saccharotrichum NBAL-S001 at the same time. The changes of Chl a and the algalysis rate of Saccharotrichum NBAL-S001 over time during the experiment are shown in Figure 2 .

[0049] from Figure 2 It can be seen that the Chl a concentration per unit water body increased rapidly under the treatment of adding sterile ddH2O and fermentation medium ( Figure 2 A). However, the addition of the fermentation broth of Saccharothricin NBAL-S001 stopped the increase of Chl a concentration in the water and gradually decreased after 12 hours. At the 120th hour of the experiment, the Chl a concentration per unit water body dropped to 0.077 μg mL -1 , and then completely remove Chl a( Figure 2 A). This indicates that the fermentation liquid of Saccharotrichum NBAL-S001 can rapidly kill Microcystis aeruginosa and has a very high algaecidal efficiency, with the algae-lysing rate reaching 97±0.13% in 5 days ( Figure 2 B).

[0050] 4. Effects of Saccharothricin NBAL-S001 Fermentation Broth on the Photosynthesis of Microcystis aeruginosa

[0051] Chlorophyll fluorescence parameters were measured using an AquaPen handheld phytoplankton fluorescence meter at 4, 12, 24, 30, 36, 48, 57, and 72 hours after the start of the experiment. The measuring light was set to 630 nm, and the water samples were measured after 15 minutes of dark adaptation under culture conditions.

[0052] The rapid light response curve of Microcystis aeruginosa was determined by the LC3 program, with the light intensity (PAR) ranging from 0 to 1000 μmolphotons m -2 s -1 The relationship between relative electron transfer rate (rETR) and PAR is fitted by the following formula:

[0053]

[0054] The maximum relative electron transfer rate (rETRmax), the photosynthesis saturation light intensity point (Ik), and the initial slope (α) are calculated as follows:

[0055]

[0056] a, b and c are obtained by fitting. The changes of rETRmax, Ik and α of Microcystis aeruginosa over time are shown in Table 1.

[0057] Table 1. Changes in the initial slope (α), maximum relative electron transfer rate (rETRmax) and saturation light intensity point (Ik) of the photosynthesis rapid light response curve of Microcystis aeruginosa under the control (+ fermentation medium) and NBAL-S001 fermentation broth treatment conditions over time. None in the table indicates that the relevant parameters cannot be obtained by fitting and calculation due to the cessation of photosynthesis of Microcystis aeruginosa. The bold data indicate that there is a significant difference compared with the control group (t-test, p<0.05, two-tailed).

[0058]

[0059] As can be seen from Table 1, the addition of the fermentation broth of Saccharotrichum NBAL-S001 reduced the sensitivity (α) of Microcystis aeruginosa to changes in light intensity, causing its maximum relative electron transfer rate (rETRmax) and the corresponding saturated light intensity (Ik) to decrease, and gradually dropped below the detection line after 30 hours. This result shows that the fermentation broth of Saccharotrichum NBAL-S001 can quickly inhibit the photosynthesis of Microcystis aeruginosa and gradually stop the photosynthesis of the algae.

[0060] The quantitative analysis of chlorophyll fluorescence induction was carried out by the JIP-test method based on the theory of "thylakoid membrane energy flow classification" and measured by the OJIP program. The calculation and physiological significance of relevant physiological parameters are as follows:

[0061] F v / F m =(F m -F o ) / F m : Maximum fluorescence efficiency of photosystem II (PSII),

[0062] W k =(F k -F o ) / (F J -F o ): oxygen-releasing complex activity,

[0063] RC / CS o =F v / F m ×VJ / V K / 4×F o : The number of reaction centers per unit PSII light-harvesting cross section,

[0064] ABS / RC=4×(F k -F o )×Fm / (F J -F o )×F v : The light energy absorbed by the PSII unit reaction center,

[0065] TR o / RC=4×(F k -F o ) / (F I -F o ): Energy captured by the PSII unit reaction center,

[0066] ET o / RC=4×(F k -F o )×(F m -F J ) / (F J -F o )×F v : Energy captured by the PSII unit reaction center for electron transfer,

[0067] DI o / RC=ABS / RC-TR o / RC: Energy dissipated by heat per unit reaction center of PSII,

[0068] M o =4×(F k -F o ) / (F m -F o ): plastoquinone electron acceptor Q A The reduction rate,

[0069] ψ Eo =1-V J :Electron transfer to Q A - The probability after

[0070] The quantum efficiency of electron transfer between photosystems,

[0071] ψ RE1o =1-V I : Electron transfer by Q A The probability of reaching Photosystem I (PSI),

[0072] PSI acceptor side electron transfer efficiency,

[0073] δ Ro =(1-V I ) / (1-V J ): the probability of electron transfer from the intersystem to the PSI acceptor side,

[0074] Among them, F O 、F K 、F J 、F I and F P (F m ) are the fluorescence intensity (au) at O ​​(~50μs), K (~300μs), J (~2ms), I (~30ms) and P (~300ms) points, respectively. The changes of photosynthetic parameters of Microcystis aeruginosa over time under the conditions of control (+fermentation medium) and fermentation broth of Saccharotrichum NBAL-S001 are shown in Figure 3-6 .

[0075] from Figure 3 It can be seen that the addition of Saccharotrichum NBAL-S001 fermentation broth rapidly reduced the maximum fluorescence efficiency of the photosystem II (PSII) of Microcystis aeruginosa ( Figure 3 A, F v / F m ), oxygen-releasing complex activity ( Figure 3 B, W k , an increase indicates a decrease in activity), and significantly reduces the number of reaction centers per unit PSII light-harvesting cross section ( Figure 3 C, RC / CS o ), and the changes in the above parameters all appeared 6 hours after adding the fermentation broth of Saccharotrichum NBAL-S001 ( Figure 3 DF). These results indicate that NBAL-S001 fermentation broth can rapidly inhibit the activity of PSII of Microcystis aeruginosa.

[0076] from Figure 4 It can be seen that the addition of Saccharotrichum NBAL-S001 fermentation broth gradually increased the light energy absorbed by the PSII unit reaction center of Microcystis aeruginosa ( Figure 4 AB, ABS / RC) and captured energy ( Figure 4 CD, TR o / RC). However, under the influence of the fermentation broth of Saccharotrichum NBAL-S001, the energy captured by the unit reaction center for electron transfer decreased ( Figure 4 E, F, ET o / RC), while the energy dissipated through heat dissipation increases ( Figure 4 GH, DI oThese results indicate that the fermentation broth of Saccharothricin NBAL-S001 hindered the efficient transfer of electrons from PSII to the downstream of the photosynthetic electron transport chain.

[0077] from Figure 5 It can be seen that the addition of the fermentation broth of Saccharothricin NBAL-S001 rapidly increased the quinone electron acceptor Q A The reduction rate ( Figure 5 AB, M o ), but electronically forwarded to Q A - The probability of the back side ( Figure 5 CD,ψ Eo ) and the electron transfer quantum efficiency ( Figure 5 EF, ) decreased. Correspondingly, under the influence of the fermentation broth of Saccharotrichum NBAL-S001, electron transfer was reduced from Q A The probability of reaching photosystem I (PSI) Figure 6 AB,ψ RE1O ), PSI acceptor side electron transfer efficiency ( Figure 6 CD, ) and the probability of electron transfer from the intersystem to the PSI acceptor side ( Figure 6 EF,δ Ro ) decreased to varying degrees. These results indicate that the fermentation broth of Saccharotrichum NBAL-S001 hinders the photosynthetic electron transfer from Q A Effective transfer to PSI.

[0078] 5. Effects of Saccharothricin NBAL-S001 Fermentation Broth on Microcystis aeruginosa under Dark Conditions

[0079] 1.5:100(V 发酵液 :V 藻液 ) was added to the M. aeruginosa solution cultured in a conical flask, and sterile fermentation medium was added in the same proportion as a control. The conical flask was cultured at 28°C and shaken three times a day to prevent a large number of algal cells from settling. In order to determine the effect of light on the algicidal effect of Saccharothrix NBAL-S001 fermentation liquid on M. aeruginosa, the light conditions in the experiment were set at 80 μmolphotons m -2 s -1 (8:16 (h:h)) and complete darkness. On the fifth day of the experiment, the concentration of Chl a per unit water volume under each treatment was Figure 7 .from Figure 7It can be seen that the algae-lytic effect of the fermentation broth of Saccharotrichum NBAL-S001 completely disappeared under dark conditions, indicating that its algae-lytic effect is highly light-dependent and induced by blocking the photosynthetic electron transport chain.

[0080] Based on the above results, NBAL-S001 fermentation broth can rapidly inactivate Microcystis aeruginosa by inhibiting the activity of PSII of Microcystis aeruginosa, hindering the electron transfer between photosystems, and enhancing photoinhibition and oxidative stress, thereby achieving the algae-lyzing effect. The algae-lyzing rate was as high as 97±0.13% in 5 days.

[0081] Example 3. Characteristics of algae-lysing active substances in the fermentation broth of Saccharotrichum NBAL-S001

[0082] 1. Algae lysis mode of Saccharothricin NBAL-S001 fermentation broth

[0083] The fermentation broth of Saccharotrichum NBAL-S001 was centrifuged (10 min, 10000 rpm) to obtain the fermentation broth supernatant and precipitated bacteria. The precipitated bacteria were washed three times with sterile water and resuspended to the original volume with sterile water to (1) obtain a resuspension of bacteria or (2) continue to use an ultrasonic oscillator to obtain a resuspension of broken bacteria. 藻液 ) were added to the Microcystis aeruginosa solution, and the mixture was placed at 28°C and 80 μmol photons m -2 s -1 The cells were cultured under the conditions of 8:16 (h:h) and samples were taken on the 5th day of the experiment to determine the concentration of Chl a. The method for determining the concentration of Chl a was as described above. The results were as follows Figure 8 shown.

[0084] from Figure 8 It can be seen that the addition of cell resuspension or crushed cell resuspension did not reduce the Chl a concentration of Microcystis aeruginosa liquid, while the addition of NBAL-S001 fermentation broth and its supernatant significantly reduced the Chl a concentration in the water. On the 5th day of the experiment, the Chl a concentration in the water was reduced to 0.015±0.01μg mL -1 0.018 ± 0.000 μg mL -1 The results showed that the algae-lysing active substances in the fermentation broth of Saccharotrichum NBAL-S001 mainly existed in the supernatant of the fermentation broth, and the algae-lysing method of the bacteria was indirect algae-lysing.

[0085] 2. Temperature and pH sensitivity of active ingredients in the supernatant of Saccharotrichum NBAL-S001 fermentation broth

[0086] The fermentation broth of Saccharothrix NBAL-S001 was centrifuged (10 min, 10000 rpm) to obtain the fermentation supernatant. The fermentation supernatant was treated at 4°C, 30°C, 60°C, 80°C and 100°C for 2 hours, and then cooled to room temperature. The fermentation supernatant was adjusted to 3, 5, 8.38, 10, and 12 using 1M HCl and saturated NaOH solution, respectively, and the pH was adjusted back to the original pH (8.38) after two hours of treatment. The fermentation supernatant after the above treatment and the fresh fermentation culture were added to the Microcystis aeruginosa solution (Chl a was 0.5 mg / L) at a ratio of 1.5:100 (V:V), and the Chl a concentration of the unit water body was measured on the 5th day of the experiment. The Chl a determination and the calculation of the algae lysis rate were as described above. The temperature and pH sensitivity of the effective active ingredients in the supernatant of the fermentation broth of Saccharothrix NBAL-S001 are as follows. Fig. 9 shown.

[0087] from Fig. 9 As can be seen from A, the effective active ingredients in the supernatant of the fermentation broth of Saccharotrichum NBAL-S001 are not sensitive to pH, and its algae lysis rate is only slightly reduced at pH 12, but it is still as high as 95±0.7% ( Fig. 9 A). In addition, the effective active ingredients in the supernatant of the fermentation broth of Saccharotrichum NBAL-S001 also showed good heat resistance. They still maintained good activity after treatment at 80°C, and their activity only decreased after treatment at 100°C (the algae lysis rate dropped to 7±2.4%) ( Fig. 9 B). The above results indicate that the effective active ingredients in the supernatant of the fermentation broth of Saccharotrichum NBAL-S001 have good pH stability and heat resistance.

[0088] Based on the above results, the present invention has newly discovered a strain of Saccharotrichum NBAL-S001, whose fermentation broth shows a very high algae-dissolving effect by hindering photosynthetic electron transfer under light, improving photoinhibition and inducing algal death by oxidative stress of algal cells. The 5-day algae-dissolving rate is as high as 97%, and the effective active substances in the fermentation broth of the strain have good pH stability and heat resistance. The above results show that Saccharotrichum NBAL-S001 has excellent development and application prospects in the prevention and control of cyanobacterial blooms.

Claims

1. A strain of Saccharotrichum Saccharothrix violaceirubra )NBAL-S001, the deposit number is CCTCC NO: M20241734.

2. A fermentation broth containing the Saccharotrichum NBAL-S001 as claimed in claim 1.

3. A Microcystis aeruginosa inhibitor, characterized in that: A living bacterial culture containing the Saccharotrichum NBAL-S001 according to claim 1.

4. A biocontrol agent for preventing and controlling cyanobacterial blooms, characterized in that: A living bacterial culture containing the Saccharotrichum NBAL-S001 according to claim 1.

5. Use of the Saccharotrichum NBAL-S001 according to claim 1 or the fermentation broth according to claim 2 in the preparation of a cyanobacterial bloom inhibitor.

6. Use of the Saccharotrichum NBAL-S001 according to claim 1 or the fermentation broth according to claim 2 in the preparation of a Microcystis aeruginosa inhibitor.

7. Use of the Saccharotrichum NBAL-S001 according to claim 1 or the fermentation liquid according to claim 2 in preventing and controlling cyanobacterial blooms.

8. The use according to claim 7, characterized in that: The cyanobacteria is Microcystis aeruginosa.

9. The use according to claim 8, characterized in that: The method comprises the step of contacting the living bacteria of Saccharothrix NBAL-S001 or the living bacteria culture containing the Saccharothrix NBAL-S001 with blue algae. The living bacteria culture of Saccharothrix NBAL-S001 is the fermentation liquid or the supernatant of the fermentation liquid of Saccharothrix NBAL-S001.

10. A method for preparing the fermentation liquid of claim 2, the Microcystis aeruginosa inhibitor of claim 3, or the biocontrol agent for preventing and controlling cyanobacterial blooms of claim 4, characterized in that: Fermentation is carried out using the Saccharotrichum NBAL-S001 as described in claim 1.

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