Arthrobacter protophormiae with high salt tolerance and its application

Abstract

The application discloses a high-salt-tolerant protease-producing Arthrobacter protophormiae and application thereof, and belongs to the technical field of environmental microorganisms.The application provides the Arthrobacter protophormiae A1 which is preserved in the China Center for Type Culture Collection on May 23, 2024, and the preservation number is CCTCC NO: M 20241041.The Arthrobacter protophormiae provided by the application can tolerate 8.0% salinity, and can effectively secrete protease under high-salt stress.The bacteria can provide effective strain resources for the anaerobic biological treatment of reinforced kitchen waste and other high-salt high-protein waste water, thereby significantly reducing the treatment cost, and have important application value.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental microorganisms, and particularly relates to a highly salt-resistant protease-producing Arthrobacterium cirrhosae and an application thereof. Background Art

[0002] High-salt, high-protein wastewater primarily originates from food industries such as restaurant waste disposal and meat curing, as well as pharmaceutical industries such as sodium heparin production. For example, restaurant wastewater is a typical example of high-salt, high-protein wastewater with high COD and protein concentrations. Anaerobic biological methods are particularly suitable for treating high-concentration organic wastewater, offering advantages such as high organic load, low energy consumption, and low sludge production. Furthermore, anaerobic fermentation technology can convert this high-concentration organic wastewater into a fermentation broth rich in small-molecule organic acids, which can be used as a carbon source for biological denitrification in wastewater treatment, thereby achieving resource utilization. In actual applications, to avoid the pH drop caused by acid production, alkaline solution is often added to maintain the optimal fermentation pH for the microorganisms, which in turn further increases the salinity of the fermentation system. However, since most anaerobic microorganisms have limited tolerance to salinity, improving treatment efficiency in high-salt environments is crucial.

[0003] In order to improve the biological treatment efficiency of high-salt wastewater, based on the concept of bioaugmentation, targeted screening of salt-tolerant functional bacteria and their addition to the reaction system is considered an effective method. Bioaugmentation technology does not require changes to the treatment process, has low usage costs, and shows strong application potential in wastewater treatment and pollutant biodegradation. Protein hydrolysis under high salt stress is the rate-limiting step in the anaerobic treatment of high-salt and high-protein wastewater, so screening for highly salt-tolerant protease-producing bacteria is very critical. Summary of the Invention

[0004] This patent discloses a highly salt-tolerant protease-producing Arthrobacterium glabratum strain and its application, which can effectively enhance the anaerobic biological treatment of high-salt and high-protein wastewater.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is: to provide a highly salt-tolerant protease-producing strain of Arthrobacterium glabratum A1, which was deposited in the China Center for Type Culture Collection on May 23, 2024, with a deposit number of CCTCC NO: M20241041.

[0006] As a preferred improvement of the present invention, the 16S rDNA sequence of the proto-Arthrobacterium vitae is shown as SEQ ID NO.1.

[0007] The first object of the present invention is to provide a highly salt-tolerant protease-producing Arthrobacter protophormiae, wherein the Arthrobacter protophormiae A1 was deposited in the China Center for Type Culture Collection on May 23, 2024, with a deposit number of CCTCC NO: M 20241041.

[0008] Optionally, in some embodiments of the present invention, the Arthrobacterium vitae secretes protease under anaerobic conditions and has a salinity tolerance of 4.0% or more.

[0009] Further optionally, in some embodiments of the present invention, the salinity tolerance is up to 8.0%.

[0010] Further optionally, in some embodiments of the present invention, the salinity tolerance is 4.0%-8.0%.

[0011] Optionally, in some embodiments of the present invention, the enzymatic activity of the protease reaches above 25 U / mL.

[0012] Further optionally, in some embodiments of the present invention, when the salinity tolerance is 4.0%-6.0%, the enzymatic activity of the protease reaches above 35 U / mL.

[0013] Further optionally, in some embodiments of the present invention, when the salinity tolerance is 6.0%-8.0%, the enzymatic activity of the protease reaches above 25 U / mL.

[0014] The second object of the present invention is to provide a use of the Arthrobacter protocis described in any one of the above items in wastewater treatment, wherein the wastewater treatment includes anaerobic fermentation of kitchen wastewater to produce organic acids.

[0015] The third object of the present invention is to provide an anaerobic fermentation inoculum for food wastewater, comprising anaerobic acid-producing activated sludge and the highly salt-tolerant protease-producing Arthrobacterium vitae described above.

[0016] Optionally, in some embodiments of the present invention, the volume ratio of the activated Arthrobacterium vitae liquid to the anaerobic acidogenic activated sludge bacterial liquid is 1:5-1:15, preferably 1:10.

[0017] A fourth object of the present invention is to provide a method for producing organic acids by anaerobic fermentation of food wastewater, comprising adding an anaerobic fermentation inoculum of food wastewater to the food wastewater, and fermenting the food wastewater at a pH of 6.5-7.5 and 30-40°C for 18-25 days. The anaerobic fermentation inoculum of food wastewater is any of the above-described anaerobic fermentation inoculums of food wastewater.

[0018] Optionally, in some embodiments of the present invention, the initial salinity of the kitchen wastewater reaches above 1.5%, and the maximum salinity during the fermentation process reaches above 3.5%.

[0019] Optionally, in some embodiments of the present invention, the protein degradation rate of the kitchen wastewater is above 80%, and the total sugar degradation rate is above 90%.

[0020] Further optionally, in some embodiments of the present invention, the protein degradation rate of the kitchen wastewater is above 90%, and the total sugar degradation rate is above 95%.

[0021] Optionally, in some embodiments of the present invention, the organic acid yield reaches 50 g / L or more.

[0022] Beneficial Effects: The Arthrobacterium protohyaloides provided by the present invention has the ability to produce proteases under high salt stress, with a salinity tolerance of over 4.0%, and a maximum tolerance of 8.0%. This bacterium can significantly enhance the anaerobic treatment of food wastewater, providing an effective bacterial strain resource for the resource-based biological treatment of high-salt, high-protein wastewater, thereby reducing treatment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : The technical process of strain screening of the present invention.

[0024] Figure 2 : Changes in COD removal efficiency during adaptive evolution.

[0025] Figure 3 : Changes in protein degradation rates during adaptive evolution.

[0026] Figure 4 : Colony morphology of strain A1.

[0027] Figure 5 : Salt tolerance of the strain.

[0028] Figure 6 : Effect of salinity on the growth of Arthrobacterium truncatum A1.

[0029] Figure 7 : Effect of salinity on protease secretion from Arthrobacterium truncatum A1.

[0030] Figure 8 : Effect of salinity on protein degradation by Arthrobacterium protothecoides A1.

[0031] Figure 9 : Bioaugmentation effect of Arthrobacter glabratus A1 on acid production from food wastewater. DETAILED DESCRIPTION

[0032] On the one hand, the present invention discloses a highly salt-resistant protease-producing Arthrobacterium vitae and its application, belonging to the field of environmental microbial technology.

[0033] like Figure 1 The process flow of screening strains of the present invention is shown, and the main steps include:

[0034] (1) First, a "top-down" adaptive evolution strategy for anaerobic bacterial communities was adopted to domesticate anaerobic chassis bacterial communities that could tolerate salinity exceeding 3.0% by gradiently increasing salt stress;

[0035] (2) Using salt-tolerant base bacterial communities as the source of strains, highly salt-tolerant and protease-producing strains were screened out.

[0036] As a preferred improvement of the present invention, the salt-tolerance adaptive evolution of the anaerobic bacterial community is carried out in a continuous-flow fully mixed anaerobic reactor, with the initial inoculum being anaerobic methanogenic activated sludge at an inoculum size of 25-35 g TS / L. Peptone is used as the sole carbon and nitrogen source, and the influent concentration is 6.0-10.0 g / L.

[0037] As a preferred improvement of the present invention, the salt tolerance adaptive evolution conditions are: temperature 30-38°C, pH 6.5-7.5, and hydraulic retention time 5-10 days. Based on a steady-state COD removal rate of >70%, the salt stress pressure is gradually increased to obtain an anaerobic bottom plate bacterial community that can tolerate salinity exceeding 3.0%.

[0038] As a preferred improvement of the present invention, highly salt-tolerant protease-producing bacteria are isolated and screened from salt-tolerant anaerobic bottom bacterial flora. The isolation and screening process includes: separation and purification using 4.0% salinity peptone solid medium, initial screening for protease production at 4.0% salinity, and secondary screening for salt tolerance at 8.0% salinity.

[0039] On the other hand, according to the above screening method, the present invention screened and provided a highly salt-tolerant protease-producing Protoglassae A1, whose preservation number is CCTCC NO: M 20241041, the preservation time is May 23, 2024, and the preservation location is China Center for Type Culture Collection.

[0040] As a preferred improvement of the present invention, the 16S rDNA of the proto-Glasnobacterium has a nucleotide sequence as shown in SEQ ID NO.1.

[0041] As a preferred improvement of the present invention, the salt tolerance of the original Arthrobacter glabraensis under anaerobic conditions can reach above 4.0%, even above 6.0%, even up to 8.0%, and it secretes protease.

[0042] The present invention also provides a use of the Arthrobacter truncatus strain in anaerobic fermentation of food wastewater to produce organic acids. After activation and culture, the Arthrobacter truncatus strain A1 is combined with an anaerobic acid-producing activated sludge solution as an inoculum (volume ratio of 1:10). Organic acids are produced by fermentation using food wastewater at a pH of 7.0 and 36°C.

[0043] The present invention will be further explained below with reference to specific examples. However, it will be readily understood by those skilled in the art that the specific process conditions and results described in the examples are merely illustrative of the present invention and should not and will not limit the present invention described in detail in the claims.

[0044] Example:

[0045] The high salt-tolerant protease producing bacteria separation and fermentation medium involved in the following examples are as follows:

[0046] ①4.0% salinity peptone solid medium: 10.0 g / L tryptone, 20.0 g / L agar, 40 g / L sodium chloride, 0.2 g / L magnesium sulfate heptahydrate, 1.0 g / L potassium dihydrogen phosphate, 1.5 g / L dipotassium hydrogen phosphate, 0.25 g / L L-cysteine ​​hydrochloride monohydrate. In addition, add 1.0 mL of vitamin solution and 1.0 mL of trace element solution per unit volume (L) to adjust the pH to 7.0.

[0047] ②4.0% salinity clear zone medium: 16.0 g / L casein, 30.0 g / L sucrose, 20.0 g / L agar, 40 g / L sodium chloride, 1.0 g / L disodium hydrogen phosphate, 0.5 g / L magnesium sulfate heptahydrate, 2.0 g / L sodium nitrate, 0.01 g / L ferrous sulfate. Adjust pH to 7.0.

[0048] ③4.0% salinity gelatin liquefaction medium: beef extract 3.0 g / L, gelatin 200.0 g / L, trypsin 5.0 g / L, sodium chloride 40 g / L, adjust the pH to 7.0.

[0049] ④LB medium: 10.0 g / L tryptone, 5.0 g / L yeast extract, 10.0 g / L sodium chloride, adjust the pH to 7.0.

[0050] ⑤ Salt-tolerance rescreening medium: Tryptone 10 g / L, sodium chloride 80 g / L, magnesium sulfate heptahydrate 0.2 g / L, potassium dihydrogen phosphate 1.0 g / L, dipotassium hydrogen phosphate 1.5 g / L, L-cysteine ​​hydrochloride monohydrate 0.25 g / L. In addition, add 1.0 mL of vitamin solution and 1.0 mL of trace element solution per unit volume (L) to adjust the pH to 7.0.

[0051] ⑥Basic fermentation medium: 6.5 g / L tryptone, 0.2 g / L magnesium sulfate heptahydrate, 1.0 g / L potassium dihydrogen phosphate, 1.5 g / L dipotassium hydrogen phosphate, 0.25 g / L L-cysteine ​​hydrochloride monohydrate. In addition, add 1 mL of vitamin solution and 1 mL of trace element solution per unit volume (L). Sodium chloride is added in varying proportions to adjust the pH to 7.0.

[0052] Example 1 Construction of salt-tolerant anaerobic chassis bacterial community

[0053] This example employs an adaptive evolution strategy for microbial communities to construct a salt-tolerant, protein-degrading chassis. Adaptive evolution was conducted in a fully mixed anaerobic reactor using a continuous flow fermentation mode, with the inoculum consisting of anaerobic methanogenic activated sludge. The reactor influent composition is shown in Table 1. Peptone was the sole carbon and nitrogen source, the initial inoculum sludge concentration was 33.0 g-TS / L, the agitation speed was 100 rpm, the fermentation temperature was 36°C, and the pH was controlled at 7.0. The initial influent salinity was 1.5%, and the hydraulic retention time was 10 days.

[0054] Table 1 Influent components of adaptive evolution reactor

[0055]

[0056] (1) Changes in COD removal rate during adaptive evolution

[0057] During the salt stress adaptive evolution process, COD removal rate was used to characterize the changes in the salt tolerance of the anaerobic bacterial community. Based on a steady-state COD removal rate exceeding 70%, the reactor inlet salinity was gradually increased to allow the anaerobic bacterial community to undergo salt tolerance adaptive evolution, ultimately achieving an anaerobic chassis bacterial community that could tolerate salinity exceeding 3.0%.

[0058] like Figure 2 As shown, the inoculated anaerobic methanogenic sludge was able to adapt quickly under 1.5% (1-6 days) and 2.0% (7-14 days) salt stress, with the effluent COD ranging from 1280 to 1920 mg / L and the COD removal rate maintained above 80%.

[0059] When the influent salinity was increased to 2.6% (15-21 days), the removal rate dropped to 64.0% and then quickly recovered to 77.6%.

[0060] When the influent salinity was further increased to 2.9% (22-51d), under this stress, COD removal first decreased to 58.1%, and then gradually recovered to 72.3%, but the tolerance response time was significantly prolonged.

[0061] When the salinity was further increased to 3.2% (52nd-61st day), the effluent COD concentration did not change significantly, and the COD removal rate remained stable between 74.4% and 84.0%.

[0062] This indicates that salt-tolerant microorganisms have become dominant through salinity gradient acclimation. However, when the salinity increases to 3.6% (62-116 days), the COD removal rate gradually decreases to around 55.0% and is difficult to recover. Therefore, the "top-down" adaptive evolution strategy of anaerobic bacterial communities can initially construct an anaerobic chassis bacterial community that tolerates 3.2% salinity.

[0063] (2) Changes in protein degradation rates during adaptive evolution

[0064] The protein degradation rate of anaerobic bacteria during adaptive evolution is as follows Figure 3 As shown in the figure, under 1.5% low salt stress, the average protein degradation rate can reach 93.2%.

[0065] As the influent salinity gradient increased and the anaerobic bacteria gradually adapted to the salt stress, protein degradation first decreased and then gradually recovered. Finally, under 3.2% salt stress, the protein degradation rate recovered to about 90%.

[0066] However, when the inlet salinity was further increased to 3.6%, the effluent protein concentration increased significantly, the protein degradation rate decreased to about 71.2%, and it was difficult to recover.

[0067] This indicates that the anaerobic bacteria have insufficient protease secretion capacity under this salt stress and protein hydrolysis is inhibited. Therefore, this example uses salt-tolerant adaptive evolved sludge obtained under 3.2% salt stress as a source to screen high salt-tolerant protease-producing bacteria.

[0068] Example 2 Directed screening of high salt-tolerant protease-producing bacteria

[0069] (1) Isolation and purification of protease-producing bacteria and initial screening of enzyme production capacity

[0070] Although a top-down adaptive evolution strategy can initially construct a salt-tolerant microbial community that can tolerate 3.2% salinity, under higher salt stress, insufficient protease secretion leads to inhibition of protein hydrolysis. Therefore, to increase protease production under high salt stress, a targeted screening of salt-tolerant enzyme-producing microorganisms was conducted from the salt-tolerant microbial community.

[0071] The isolation and screening process involves placing an anaerobic bacterial colony in an anaerobic tube, adding glass beads, and vortexing to disperse the anaerobic bacteria. The suspension is then diluted with saline solution. The diluted suspension is then plated onto a 4.0% salinity peptone solid medium plate and incubated in an inverted incubator at 36°C for 48 hours. The resulting single colonies are then purified using the plate streak method. The purified strains are then stored on a 4.0% salinity solid slant medium.

[0072] A total of 16 strains (designated A1-A16) were isolated and purified at 4.0% salinity. These strains were inoculated onto 4.0% salinity clear zone medium and 4.0% salinity gelatin liquefaction medium using the three-point method and puncture inoculation, respectively. The ratio of clear zone diameter to colony diameter (>1.5) and the degree of gelatin liquefaction were used as evaluation criteria to screen for salt-tolerant strains with strong protease production. As shown in Table 2, 56.25% of the strains had a clear zone diameter / colony diameter ratio of 1.5 < 2. Nine strains (A1, A2, A3, A4, A5, A7, A8, A10, and A13) with a ratio >1.5 and high gelatin liquefaction were selected for further analysis of their salt tolerance.

[0073] Table 2 Preliminary screening of enzyme production capacity of protease-producing bacteria

[0074]

[0075]

[0076] (2) Rescreening of salt tolerance of protease-producing bacteria

[0077] The protease-producing bacteria screened were subjected to salt tolerance rescreening. The specific process included: after the screened strains were cultured in LB liquid medium for 48 hours, the diluted bacterial suspensions were respectively applied to 8.0% salinity salt tolerance rescreening solid medium, and then the protease-producing bacteria that could tolerate 8.0% salinity were screened (such as Figure 4 shown).

[0078] like Figure 5 As shown in the figure, after 48 h of batch fermentation in 8.0% salt-tolerant secondary screening medium, the biomass of the fermentation broth of strain A1 was significantly higher than that of other strains, and the OD 600 The value of the salt tolerance test was 0.95. Therefore, strain A1 had a better salt tolerance.

[0079] (3) Identification of bacterial species

[0080] The 16S rDNA sequence of strain A1 obtained by screening using bacterial universal primers was amplified and then sent to Shanghai Sangon Biotech Co., Ltd. for sequencing. Its 16S rDNA sequence is shown in SEQ ID NO.01, and the strain sequence length is 1437bp. The 16S rDNA sequence was compared on GenBank. The results showed that its 16S rDNA sequence similarity with that of Arthrobacter protophormiae (GenBank Number: GQ395612.1) was as high as 99.72%. Therefore, the highly salt-tolerant protease-producing strain was identified as Arthrobacter protophormiae, and was deposited in the China Center for Type Culture Collection on May 23, 2024. Its preservation number is CCTCCNO: M 20241041, and it was named Arthrobacter protophormiae A1. Example 3 Salt tolerance of Arthrobacter protophormiae A1

[0081] (1) Effect of salinity on the growth of Arthrobacterium truncatum A1

[0082] The original glass fly Arthrobacter A1 was transferred to the basic culture medium for batch fermentation to investigate the effects of salt stress on its growth, protease secretion and protein degradation. The growth curves under different salinity (2.0%, 4.0%, 6.0%, 8.0%) are shown in Figure 2. Figure 6 As shown, it can grow under salinity conditions of 2.0%-8.0%. When the salinity reaches 4.0%, 6.0% and 8.0%, the strain has the highest biomass (OD 600 ) were 1.68, 1.32 and 0.99, respectively, compared with 2.0% salinity (the highest OD 600 =1.76) decreased by 4.5%, 25.0%, and 43.7%, respectively. Accordingly, it can be concluded that at high salinity levels of 4.0%, 6.0%, and 8.0%, the maximum biomass retention rates reached 95.5%, 75.0%, and 56.3%, respectively. This shows that Arthrobacter protocis A1 has a high salt tolerance. Although high salinity can inhibit its growth efficiency to a certain extent, it can still maintain more than half of its maximum biomass at a high salinity of 8.0%.

[0083] (2) Effect of salinity on protease secretion by Arthrobacterium truncatum A1

[0084] Effects of salinity on the secretion of protease by Arthrobacterium truncatum A1 Figure 7As shown, the protease activity in the fermentation broth under different salt stresses reached its maximum value during the bacterial growth stabilization period (the second day). At salinity levels of 2.0%, 4.0%, 6.0%, and 8.0%, the maximum enzyme activity values ​​were 55.2 U / mL, 52.6 U / mL, 35.9 U / mL, and 25.5 U / mL, respectively. It can be concluded that when the salinity reached 4.0%, 6.0%, and 8.0%, the enzyme activity remained at 95.3%, 65.0%, and 46.2% compared to that at 2.0%. This indicates that Arthrobacter protophyte A1 can still effectively grow and secrete proteases under high salt stress.

[0085] (3) Effect of salinity on protein degradation by Arthrobacterium truncatum A1

[0086] Effects of salinity on protein degradation by Arthrobacterium protothecoides A1 Figure 8 As shown in Figure 3, after 3 days of anaerobic batch fermentation at salinity levels of 2.0%, 4.0%, 6.0%, and 8.0%, the protein degradation rates reached 61.1%, 55.1%, 48.9%, and 41.4%, respectively. This indicates that Arthrobacter protocis A1 can effectively hydrolyze proteins under high salt stress.

[0087] Example 4 Application of Arthrobacter glabratus A1 in anaerobic acid production from actual restaurant wastewater

[0088] The food wastewater in this embodiment comes from high-concentration organic wastewater generated after sorting, crushing and three-phase separation pretreatment in a centralized food waste treatment plant.

[0089] The wastewater had COD concentrations and salinity levels as high as 109.7 g / L and 1.7%, respectively, with crude protein and total sugar concentrations of 24.9 g / L and 28.3 g / L, respectively. In this example, Arthrobacter glabratus A1 was activated in LB medium and then inoculated with anaerobic acidogenic activated sludge (1:10 volume ratio) as an inoculum. Anaerobic acidogenesis was carried out in a 5L fermentor using food wastewater, with the pH and temperature controlled at 7.0 and 36.0°C, respectively. A fermentor inoculated only with anaerobic acidogenic activated sludge served as a control.

[0090] The results are as follows Figure 9 As shown in the figure, after 21 days of anaerobic fermentation, the final production of organic acid in the bacteria-added group was 55.1 g / L, which was significantly increased by 38.8% compared with the control group.

[0091] Along with the production of organic acids, in order to avoid the pH drop caused by acid production, which would weaken the metabolic activity of microorganisms, it is necessary to add alkali solution to maintain the pH stability throughout the fermentation process. However, the addition of alkali solution will gradually increase the salinity of the fermentation system. The highest salinity during the fermentation process in the bacteria-added group and the control group reached 3.9% and 3.3%, respectively. In a high-salt environment, the total sugar degradation rate of the control group was 87.9%, while the protein degradation rate was only 56.7%. In contrast, the original glass fly A1 significantly enhanced protein conversion. Even in a higher salinity environment, the total sugar and protein degradation rates of the bacteria-added group reached 95.3% and 92.8%, respectively. This shows that the original glass fly A1 can effectively enhance the anaerobic treatment effect of high-salt and high-protein wastewater such as kitchen wastewater.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A highly salt-tolerant protease-producing Arthrobacterium cirrhosae strain, characterized by: The Arthrobacter protophormiae A1 was deposited in the China Center for Type Culture Collection on May 23, 2024, with a deposit number of CCTCC NO: M 20241041.

2. The Arthrobacterium protothecoides according to claim 1, characterized in that: The Arthrobacter glabracens can secrete protease under anaerobic conditions and has a salinity tolerance of more than 4.0%.

3. The Arthrobacterium protothecoides according to claim 2, characterized in that: The enzymatic activity of the protease is above 25 U / mL.

4. The Arthrobacterium protothecoides according to claim 3, characterized in that: When the salinity is 4.0%-6.0%, the activity of the protease is above 35 U / mL.

5. The Arthrobacterium protothecoides according to claim 3, characterized in that: When the salinity is 6.0%-8.0%, the activity of the protease is above 25 U / mL.

6. Use of the Arthrobacterium protovitaminosis according to any one of claims 1 to 5 in wastewater treatment, wherein the wastewater treatment comprises anaerobic fermentation of kitchen wastewater to produce organic acids.

7. An anaerobic fermentation inoculum of food wastewater, characterized by: The method comprises anaerobic acid-producing activated sludge and the highly salt-tolerant protease-producing Arthrobacterium glabratum according to claims 1-5.

8. The anaerobic fermentation inoculum of food wastewater according to claim 7, characterized in that: The volume ratio of the activated liquid of Arthrobacter glabratus to the bacterial liquid of the anaerobic acidogenic activated sludge is 1:5-1:

15.

9. The anaerobic fermentation inoculum of food wastewater according to claim 8, characterized in that: The volume ratio of the activated liquid of Arthrobacter glabratus to the bacterial liquid of the anaerobic acidogenic activated sludge is 1:

10.

10. A method for producing organic acids by anaerobic fermentation of food wastewater, characterized by: Adding anaerobic fermentation inoculum of kitchen wastewater to kitchen wastewater, and fermenting at pH 6.5-7.5 and 30-40° C. for 18-25 days, wherein the anaerobic fermentation inoculum of kitchen wastewater is the anaerobic fermentation inoculum of kitchen wastewater according to any one of claims 7-9.

11. The method according to claim 10, characterized in that: The initial salinity of the kitchen wastewater is above 1.5%, and the highest salinity during the fermentation process is 3.3%.

12. The method according to claim 10, wherein: The protein degradation rate of the kitchen wastewater is above 70%.

13. The method according to claim 12, wherein: The protein degradation rate of the kitchen wastewater is above 80%, and the total sugar degradation rate is above 90%.

14. The method according to claim 13, wherein: The protein degradation rate of the kitchen wastewater is above 90%, and the total sugar degradation rate is above 95%.

15. The method according to claim 10, wherein: The organic acid yield is above 50 g / L.

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