Candida tropicalis HWDY-JD-001 and application thereof in degrading aliphatic organic amine

Abstract

The application belongs to the technical field of environmental microorganisms, and provides a Candida tropicalis HWDY-JD-001 and application thereof in degrading aliphatic organic amine. The preservation number of the strain provided by the application is CGMCC No. 39009. The strain has the ability of efficiently degrading aliphatic organic amine, and after fermentation culture, is added to a biochemical system for treating wastewater containing aliphatic organic amine, so that the degradation efficiency and removal rate of the biochemical system to aliphatic organic amine are improved, the toxicity and impact of aliphatic organic amine on denitrifying microorganisms such as nitrifying bacteria and denitrifying bacteria in the biochemical system are reduced, and the stability of the operation of the biochemical system is improved, which has important practical application value and environmental significance for wastewater denitrification.

Description

Technical Field

[0001] This invention belongs to the field of environmental microbiology technology, and specifically relates to a strain of Candida tropicalis HWDY-JD-001 and its application in the degradation of aliphatic organic amines. Background Technology

[0002] Against the backdrop of continuous global industrialization, the discharge of various industrial wastewater and domestic sewage continues to increase, leading to increasingly prominent nitrogen pollution problems in water bodies. Eutrophication has become a global water pollution challenge, severely disrupting ecological balance and threatening water resource security. Wastewater denitrification, as a core component of wastewater treatment, directly determines whether the effluent quality meets standards. Aliphatic organic amines, typical organic nitrogen pollutants, are widely present in wastewater from industries such as chemical, pharmaceutical, and dyeing, becoming a key obstacle restricting the efficiency of wastewater denitrification.

[0003] Currently, the main methods for treating aliphatic organic amine wastewater include physical, chemical, and biological methods. While physical methods (such as adsorption and distillation) and chemical methods (such as oxidation and neutralization) have high treatment efficiency, they suffer from drawbacks such as high cost and the potential for secondary pollution. Biological methods utilize the metabolic activity of microorganisms to degrade organic amines into harmless substances (such as CO2, H2O, and NH3), offering advantages such as low cost, environmental friendliness, and no secondary pollution, and have become the mainstream approach for treating aliphatic organic amine wastewater.

[0004] However, aliphatic organic amines are not only highly toxic, causing damage to the human respiratory and nervous systems, but they also significantly inhibit microorganisms in wastewater biological treatment systems, disrupting the stability of microbial community structure, reducing microbial metabolic activity, and thus drastically weakening wastewater denitrification efficiency, leading to excessive nitrogen content in effluent. Currently, wastewater denitrification treatment largely relies on the domestication of mixed microbial communities, which requires complex transitions between anaerobic / anoxic and aerobic conditions. This results in problems such as long treatment cycles, large land areas, and high energy consumption. Furthermore, existing microbial strains have limited ability to degrade aliphatic organic amines, making it difficult to achieve efficient and broad-spectrum degradation effects, and failing to meet the actual needs of complex wastewater denitrification treatment.

[0005] Against this backdrop, screening functional microbial strains with strong adaptability and excellent degradation efficiency has become crucial to overcoming existing technological bottlenecks. *Candida tropicalis*, as a superior beneficial microorganism, possesses outstanding stress resistance, enabling it to stably grow and reproduce in complex wastewater environments with high salinity and fluctuating pH levels. Its extensive metabolic capacity demonstrates good degradation potential for various organic pollutants, and it has already been applied in food fermentation, wastewater treatment, and other fields. However, research on its degradation of aliphatic organic amines has not yet been reported. Applying it to the degradation of aliphatic organic amines can effectively overcome the problem of aliphatic organic amines inhibiting wastewater denitrification, improve wastewater denitrification efficiency, and provide a novel technological pathway for the efficient treatment of organic nitrogen pollutants in wastewater, possessing significant practical value and application prospects. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a strain of Candida tropicalis, HWDY-JD-001, and its application in the degradation of aliphatic organic amines. This strain, with accession number CGMCC No. 39009, exhibits strong resistance and can stably grow and reproduce in complex wastewater environments. It possesses a highly efficient ability to degrade aliphatic organic amines. After fermentation, it is added to a wastewater treatment biochemical system containing aliphatic organic amines. By improving the degradation efficiency and removal rate of aliphatic organic amines in the biochemical system, it reduces the toxicity and impact of aliphatic organic amines on denitrifying bacteria and other nitrogen-degrading microorganisms in the system. This effectively overcomes the problem of aliphatic organic amines inhibiting wastewater denitrification and improves wastewater denitrification efficiency.

[0007] The technical solution of this invention is:

[0008] The first aspect of this invention provides a strain of *Candida tropicalis* HWDY-JD-001, which was deposited on October 20, 2025, at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, and is classified as *Candida tropicalis*. Candida tropicalis The accession number is CGMCC No. 39009.

[0009] The nucleotide sequence of the 18S rDNA of the above strain is shown in SEQ ID NO.1.

[0010] The isolation and screening process of the tropical Candida albicans HWDY-JD-001 is as follows:

[0011] 1. Sample collection: Take 5-10 mL of activated sludge from the aerobic tank of the wastewater treatment biochemical system of Qilu Branch of Sinopec Catalyst Co., Ltd., put it into a sterile Erlenmeyer flask, add 40-50 mL of sterile physiological saline, and shake and incubate at 150-200 r / min and 28-32℃ for 30-60 min to obtain a bacterial suspension.

[0012] 2. Enrichment culture: Take 10 mL of bacterial suspension and inoculate it into an enrichment medium containing 100 mg / L methylamine and 100 mg / L triethylamine. Incubate at 28-32℃ and 150-200 r / min for 7-10 days with shaking. During this period, subculture every 2-3 days and gradually increase the concentration of methylamine and triethylamine to 500-1000 mg / L.

[0013] 3. Isolation and purification: Take the bacterial suspension from the last enrichment culture and perform serial dilutions. Spread the bacterial suspensions of different dilutions onto selective medium plates containing 500 mg / L methylamine and 500 mg / L triethylamine, respectively. Incubate at 28-32℃ for 24-48 h. Pick single colonies and purify them by streak multiple times to obtain pure strains.

[0014] 4. Identification: Morphological and molecular biological identification was performed on the pure strain. Morphological identification showed that the colonies of this strain were milky white, round, smooth, with regular edges, and the cells were oval or round, exhibiting budding reproduction. Molecular biological identification showed that the 18S rRNA gene sequence of this strain was similar to that of four strains of Candida tropicalis (…). Candida tropicalis The homology with the strain was as high as 100%, and based on the morphological characteristics, the strain was identified as Candida tropicalis.

[0015] The formulations of the enrichment and selection media are as follows: KH2PO4 1.5 g / L, K2HPO4 3.0 g / L, MgSO4·7H2O 0.5 g / L, FeSO4·7H2O 0.01 g / L, aliphatic organic amines (such as methylamine, triethylamine) 100-500 mg / L, distilled water 1000 mL, pH 6.0-7.0, and 15-20 g / L agar added to the selection medium.

[0016] A second aspect of the present invention is to provide a microbial agent obtained by culturing the aforementioned Candida tropicalis HWDY-JD-001, the culturing method of which is as follows:

[0017] (1) Slant culture: The strain of Candida tropicalis HWDY-JD-001 was inoculated into PDA slant medium and cultured at 28-32℃ for 24-48 h to obtain slant seeds;

[0018] (2) Seed culture: The slant seeds were inoculated into the seed culture medium and cultured with shaking at 28-32℃ and 150-200 r / min for 18-24 h to obtain the seed culture;

[0019] (3) Fermentation expansion culture: The seed liquid is inoculated into the fermentation medium of the fermenter at an inoculation amount of 5-10 VT% for expansion culture. The culture conditions are: 28-32℃, pH: 6.5-7.2, tank pressure 0.05 MPa, DO control ≥20%, fermentation cycle 24-30h, to obtain fermentation broth, i.e. inoculum.

[0020] Preferably, in (1), the formula of PDA slant culture medium is: 200 g / L potato, 20 g / L glucose, 15-20 g / L agar, 1000 mL distilled water, pH 6.8-7.2.

[0021] Preferably, in (2), the seed culture medium formula is: glucose 10-20 g / L, peptone 5-10 g / L, yeast extract 3-5 g / L, NaCl 5 g / L, distilled water 1000 mL, pH 6.0-7.0.

[0022] Preferably, in (3), the fermentation medium is: glucose 10-20 g / L, soybean meal 5-10 g / L, yeast powder 1-5 g / L, magnesium sulfate 0.3-0.5 g / L, potassium dihydrogen phosphate 0.5-1.0 g / L, dipotassium hydrogen phosphate 0.5-1.0 g / L, manganese sulfate 0.1-0.3 g / L, and polyether defoamer 1-2 g / L.

[0023] The third aspect of the present invention is the application of the above-mentioned Candida tropicalis strain HWDY-JD-001 and / or the above-mentioned microbial agent in the degradation of aliphatic organic amines, mainly in the degradation of wastewater containing aliphatic organic amines.

[0024] As a preferred option, aliphatic organic amines include, but are not limited to, one or more of methylamine, ethylamine, propylamine, dimethylamine, diethylamine, dipropylamine, trimethylamine, and triethylamine.

[0025] This strain can be used to treat wastewater contaminated with organic amines. The specific application method is as follows:

[0026] The fermentation broth (inoculum) of Candida tropicalis HWDY-JD-001 in this invention was added to wastewater containing aliphatic organic amines at a volume ratio of 1‰-5‰, and aerated for 24-72 h under the conditions of 10-40℃, pH 5.0-8.0 and dissolved oxygen ≥2 mg / L.

[0027] The concentration of aliphatic organic amines in the wastewater ranges from 0 to 1500 mg / L.

[0028] The present invention has the following advantages and effects compared with the prior art:

[0029] (1) The tropical Candida albicans HWDY-JD-001 provided by the present invention has the ability to efficiently degrade aliphatic organic amines. It has a good degradation effect on a variety of aliphatic organic amines such as methylamine, ethylamine, propylamine, dimethylamine, diethylamine, dipropylamine, trimethylamine, and triethylamine. Data shows that when the concentration of aliphatic organic amines in wastewater is ≤500 mg / L, the degradation rate can reach 100% in 24 hours; when the concentration is ≤1000 mg / L, the degradation rate can reach 100% in 72 hours; and when the concentration is ≤1500 mg / L, the degradation rate can reach more than 85% in 72 hours.

[0030] (2) This strain has a wide range of adaptability. It can grow normally and degrade aliphatic organic amines under conditions of 10-40℃ and pH 5.0-8.0, and has strong tolerance to high concentrations of organic amines (1500 mg / L).

[0031] (3) The strain has a simple culture method, fast growth rate, is easy to scale up production, and has low application cost;

[0032] (4) This strain is environmentally friendly and does not cause secondary pollution. It can be widely used in the treatment of aliphatic organic amine polluted wastewater and has important practical application value and environmental significance. Attached Figure Description

[0033] Figure 1 The colony morphology of the tropical Candida tropicalis strain HWDY-JD-001 on a selective medium plate according to the present invention;

[0034] Figure 2 This is a microscopic morphological image of the *Candida tropicalis* strain HWDY-JD-001 of this invention.

[0035] Figure 3 This is a graph showing the concentration changes of aliphatic organic amines during the field experiment of Example 6 of the present invention;

[0036] Figure 4 This is a graph showing the change in ammonia nitrogen concentration during the field experiment in Example 6 of the present invention. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0038] Example 1: Isolation, screening and identification of Candida tropicalis HWDY-JD-001

[0039] 1. Sample collection: 10 mL of activated sludge was taken from the aerobic tank of the wastewater treatment biochemical system of Qilu Branch of Sinopec Catalyst Co., Ltd., placed in a sterile Erlenmeyer flask, and 50 mL of sterile physiological saline was added. The flask was shaken and cultured at 200 r / min and 30℃ for 40 min to obtain a bacterial suspension.

[0040] 2. Enrichment culture: Take 10 mL of bacterial suspension and inoculate it into an enrichment medium containing 100 mg / L methylamine and 100 mg / L triethylamine. Incubate at 30℃ and 200 r / min for 7 days with shaking. During this period, subculture every 3 days and gradually increase the concentration of methylamine and triethylamine to 500 mg / L.

[0041] 3. Isolation and purification: Take the bacterial culture from the last enrichment culture and perform serial dilutions, taking 10... -5 10 -6 10 -7 Diluted bacterial suspensions were plated onto selective medium plates containing 500 mg / L methylamine and 500 mg / L triethylamine, respectively, and incubated at 30°C for 48 h. Single colonies with regular morphology and good growth were picked, and after multiple purifications, a pure strain was obtained, designated HWDY-JD-001. The colony morphology of this strain on selective medium plates is shown in the figure. Figure 1 The morphology of the strain under a microscope is shown in the following figures. Figure 2 .

[0042] 4. Identification:

[0043] (1) Morphological identification: The colonies of this strain are milky white, round, smooth, with regular edges, and the cells are oval or round, and reproduce by budding;

[0044] (2) Molecular biological identification: Genomic DNA was extracted from the strain and PCR amplification was performed using universal primers for the 18S rRNA gene. After sequencing, the amplified products were compared with sequences in the GenBank database for homology. The results showed that the 18S rRNA gene sequence of this strain was similar to that of Candida tropicalis. Candida tropicalis With 100% homology, and based on morphological characteristics, this strain was identified as *Candida tropicalis*, and named... Candida tropicalis The accession number is CGMCC No. 39009; the nucleotide sequence of the 18S rDNA of the above strain is shown in SEQ ID NO. 1.

[0045] In various embodiments of the present invention, this strain is named Candida tropicalis HWDY-JD-001.

[0046] The formulations of the enrichment and selection media are as follows: KH2PO4 1.5 g / L, K2HPO4 3.0 g / L, MgSO4·7H2O 0.5 g / L, FeSO4·7H2O 0.01 g / L, aliphatic organic amines (such as methylamine, triethylamine) 100-500 mg / L, distilled water 1000 mL, pH 6.0-7.0, and 15-20 g / L agar added to the selection medium.

[0047] Example 2: Cultivation of Candida tropicalis HWDY-JD-001

[0048] The cultivation method for Candida tropicalis HWDY-JD-001 is as follows:

[0049] (1) Slant culture: Candida tropicalis HWDY-JD-001 was inoculated into PDA slant medium and cultured at 30℃ for 36 h to obtain slant seed;

[0050] PDA slant culture medium formula: potato 200 g / L, glucose 20 g / L, agar 18 g / L, distilled water 1000 mL, pH 7.0.

[0051] (2) Seed culture: The slant seeds were inoculated into the seed culture medium and cultured with shaking at 30℃ and 180 r / min for 24 h to obtain the seed culture;

[0052] Seed culture medium formula: glucose 15 g / L, peptone 8 g / L, yeast extract 4 g / L, NaCl 5 g / L, distilled water 1000 mL, pH 6.5;

[0053] (3) Fermentation expansion culture: The seed liquid was inoculated into the fermentation medium of the fermenter at an inoculation amount of 10 VT% for expansion culture. The culture conditions were: 30℃, pH: 7.0, tank pressure 0.05 MPa, DO control ≥20%, fermentation cycle 24h, to obtain the fermentation broth of Candida tropicalis HWDY-JD-001, i.e., the inoculum;

[0054] The above-mentioned fermentation medium formula is as follows: glucose 15 g / L, soybean meal 6 g / L, yeast powder 3 g / L, magnesium sulfate 0.3 g / L, potassium dihydrogen phosphate 0.8 g / L, dipotassium hydrogen phosphate 0.8 g / L, manganese sulfate 0.1 g / L, and polyether defoamer 1 g / L.

[0055] Tests showed that the bacterial cell concentration in the fermentation broth could reach 2×10⁻⁶. 10 CFU / mL.

[0056] Example 3: Degradation effect of Candida tropicalis HWDY-JD-001 on different aliphatic organic amines

[0057] Experimental method: The fermentation broth prepared in Example 2 was added to simulated wastewater containing different types and concentrations of aliphatic organic amines at a volume ratio of 5‰. The control group was inoculated with distilled water at a volume ratio of 5‰. Under the conditions of 30℃, pH 7.0 and dissolved oxygen ≥2mg / L, the mixture was continuously shaken and cultured for 72h. Samples were taken every 24h to detect the changes in the content of aliphatic organic amines.

[0058] The degradation effects of aliphatic organic amines were verified using methylamine, dimethylamine, and triethylamine. The simulated wastewater contained the following components in addition to the aliphatic organic amines: magnesium sulfate 0.3 g / L, potassium dihydrogen phosphate 1.5 g / L, dipotassium hydrogen phosphate 3.0 g / L, manganese sulfate 0.1 g / L, ferrous sulfate 0.1 g / L, zinc sulfate 0.1 g / L, and sodium chloride 1.0 g / L.

[0059] The following table shows the relevant detection data for aliphatic organic amines:

[0060] Table 1. Methylamine degradation data

[0061]

[0062] Table 2 Dimethylamine degradation data

[0063]

[0064] Table 3. Triethylamine degradation data

[0065]

[0066] Table 4 Degradation data of mixed fatty amines (methylamine: dimethylamine: triethylamine = 1:1:1)

[0067]

[0068] Experimental results showed that the inoculum obtained from the cultivation of *Candida tropicalis* HWDY-JD-001 exhibited good degradation effects on various aliphatic organic amines. When the concentration of aliphatic organic amines was ≤500 mg / L, the degradation rate reached 100% after 24 hours; when the concentration was ≤1000 mg / L, the degradation rate reached 100% after 72 hours; and when the concentration was ≤1500 mg / L, the degradation rate reached over 85% after 72 hours.

[0069] Example 4: Degradation effect of Candida tropicalis HWDY-JD-001 on aliphatic organic amines under high salinity conditions.

[0070] Experimental method: Triethylamine was selected as a representative aliphatic organic amine to verify its degradation effect. The fermentation broth prepared in Example 2 was added to simulated wastewater with different salt contents and containing 1000 mg / L triethylamine at a volume ratio of 5‰. Under the conditions of 30℃, pH 7.0 and dissolved oxygen ≥2 mg / L, the mixture was continuously shaken and cultured for 72 h. Samples were taken every 24 h to detect the change in triethylamine content.

[0071] The control group simulated wastewater, excluding triethylamine, contained the following components: magnesium sulfate 0.3 g / L, potassium dihydrogen phosphate 1.5 g / L, dipotassium hydrogen phosphate 3.0 g / L, manganese sulfate 0.1 g / L, ferrous sulfate 0.1 g / L, zinc sulfate 0.1 g / L, and sodium chloride 1.0 g / L. The experimental group simulated wastewater, based on the control group's simulated wastewater, had sodium chloride added at concentrations of 10.0 g / L, 20.0 g / L, 30.0 g / L, 40.0 g / L, and 50.0 g / L, respectively, to create different high-salt, high-osmotic environments.

[0072] The table below shows the relevant test data on the degradation effect of triethylamine under high-salt conditions:

[0073] Table 5. Degradation data of triethylamine under high salinity conditions

[0074]

[0075] Experimental results show that *Candida tropicalis* HWDY-JD-001 exhibits strong salt tolerance. In a total salinity environment below 3%, its degradation efficiency for aliphatic organic amines remains unaffected. In a 4% total salinity environment, the degradation rate of aliphatic organic nitrogen reaches 90.7% within 72 hours. Even in a high salinity environment of 5%, its degradation efficiency remains at 67.5% after 72 hours. These results demonstrate that *Candida tropicalis* HWDY-JD-001 possesses excellent salt tolerance, can grow and reproduce normally under high salt stress conditions, and can efficiently degrade aliphatic organic amines, thus making it suitable for treating aliphatic organic amines in high-salt wastewater.

[0076] Example 5: Candida tropicalis HWDY-JD-001 relieves the inhibition of nitrifying bacteria by aliphatic organic amines.

[0077] The simulated wastewater was prepared using nitrifying bacteria culture medium and triethylamine at different concentrations. The concentrations of each component in the nitrifying bacteria culture medium were 0.5 g / L ammonium sulfate, 0.2 g / L sodium chloride, 0.03 g / L ferrous sulfate, 0.03 g / L magnesium sulfate, 0.15 g / L potassium dihydrogen phosphate, and 0.22 g / L dipotassium hydrogen phosphate; the triethylamine concentrations were 0, 50 mg / L, and 100 mg / L, with the remainder being water.

[0078] The nitrifying bacteria agent is an autotrophic nitrifying bacteria produced by Huawodeyuan Environmental Technology (Jinan) Co., Ltd. It consists of two functional bacterial groups: ammonia oxidizing bacteria and nitrite oxidizing bacteria. The ammonia oxidation rate is ≥500 mg / (Lh), and other product indicators meet HG / T 5925-2021.

[0079] Table 6 Experimental Design

[0080]

[0081] Table 7 Changes in ammonia nitrogen concentration during the experiment

[0082]

[0083] Experimental results showed that in wastewater without triethylamine, the degradation rate of ammonia nitrogen by nitrifying bacteria was 99.2% after 72 hours. At a triethylamine concentration of 50 mg / L, the ammonia nitrogen degradation rate in experimental group 1, with the addition of *Candida tropicalis* HWDY-JD-001, was 79.9%, a 50.8% increase compared to control group 1. At a triethylamine concentration of 100 mg / L, the ammonia nitrogen degradation rate in experimental group 2, with the addition of *Candida tropicalis* HWDY-JD-001, was 38.9%, a 34.0% increase compared to control group 2. This indicates that *Candida tropicalis* HWDY-JD-001 can efficiently degrade aliphatic organic amines in amine- and ammonia-containing wastewater, eliminating or reducing their toxic inhibitory effects on nitrifying bacteria, ensuring the relative stability of nitrifying bacteria function in conventional activated sludge systems, and providing an efficient and feasible technical pathway for the denitrification treatment of this type of recalcitrant wastewater.

[0084] Example 6: Application of Candida tropicalis HWDY-JD-001 in the treatment of aliphatic organic amine contaminated wastewater

[0085] 1. Project Overview

[0086] The field application experiment was conducted on the wastewater biological treatment unit of a chemical enterprise (mainly producing polyetheramine) in Linzi District, Zibo City, Shandong Province. The wastewater treatment plant adopts an A / O (anaerobic-aerobic) biological nitrogen removal process, with two parallel lines running in the north and south, each designed to treat 500 m³ / d. The wastewater to be treated contains aliphatic organic amines (mainly methane, propylenediamine, and triethylamine), ammonia nitrogen, and other pollutants. Because aliphatic organic amines have a strong inhibitory effect on nitrifying bacteria, the conventional A / O process has low ammonia nitrogen removal efficiency, making it difficult to meet effluent standards. This embodiment verifies the degradation effect of heated Candida albicans on organic amines and its effect on relieving the inhibition of nitrifying bacteria by adding heated Candida albicans to one of the A / O lines.

[0087] 2. Experimental Materials and Process Parameters

[0088] 2.1 Influent wastewater quality: pH 7.2-7.8, COD 400-550 mg / L, total aliphatic organic amine concentration 60-80 mg / L, ammonia nitrogen concentration 80-90 mg / L, total salt content 1.5%-1.8%. Effluent quality from the biological treatment system: total aliphatic organic amine concentration 30-50 mg / L, ammonia nitrogen concentration 30-40 mg / L.

[0089] 2.2 Experimental Grouping:

[0090] Experimental group: A / O process column I (south column), with heated zone Candida albicans inoculum, effective viable count ≥2×10⁻⁶. 10 CFU / mL, the dosage is 5‰ of the volume of tank O;

[0091] Control group: A / O process II column (north column), no bacterial agent was added, and only the conventional activated sludge system was maintained.

[0092] 2.3 Process operating parameters: Section A (anoxic section), DO≤0.5 mg / L; Section O (aerobic section), DO 2.0-4.0 mg / L; sludge age 15d, MLSS controlled at 3000-4500mg / L; internal recirculation ratio 200%, no external carbon source added.

[0093] 3. Implementation Process and Results

[0094] The two sets of experiments were run synchronously and continuously for 72 hours. Water samples were taken from the biochemical system at 0 hours, 24 hours, 48 ​​hours, and 72 hours after addition for testing. The data are recorded in the table below:

[0095] Table 8. Changes in the concentrations of aliphatic organic amines and ammonia nitrogen during the field experiment.

[0096]

[0097] Changes in aliphatic organic amine and ammonia nitrogen concentrations during the field experiment are shown in the figure. Figure 3 and Figure 4 .

[0098] 4. Results Analysis

[0099] 4.1 Degradation effect of organic amines: After 72 hours of operation, the concentration of aliphatic organic amines in the experimental group decreased from 43.2 mg / L to 0 mg / L, with a degradation rate of 100%; the control group showed no significant change, indicating that Candida tropicalis can efficiently degrade aliphatic organic amines in wastewater.

[0100] 4.2 Ammonia Nitrogen Removal Efficiency: In the experimental group, ammonia nitrogen decreased from 34.6 mg / L to 2.8 mg / L, achieving a removal rate of 91.9%, with effluent ammonia nitrogen ≤5 mg / L, meeting the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB 18918-2002). In the control group, ammonia nitrogen showed no significant change and fell far short of the standard. This indicates that the *Candida tropicalis* inoculant, by degrading aliphatic organic amines, relieved their toxic inhibitory effect on nitrifying bacteria, thus ensuring and enhancing the nitrification and denitrification function of the A / O process.

[0101] 5. Conclusion

[0102] This embodiment demonstrates that in the A / O treatment process of industrial wastewater containing aliphatic organic amines, the addition of heated Candida albicans can achieve complete degradation of organic amines, effectively relieve their inhibitory effect on nitrifying bacteria, significantly improve ammonia nitrogen removal efficiency, and stably reduce effluent ammonia nitrogen to below 5 mg / L, providing an efficient and stable technical solution for the treatment of this type of recalcitrant wastewater to meet standards.

[0103] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. All equivalent changes and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A strain of Candida tropicalis HWDY-JD-001, characterized in that, The strain was deposited at the China General Microbiological Culture Collection Center on October 20, 2025, and its taxonomic name is: *Candida tropicalis*. Candida tropicalis The accession number is CGMCC No. 39009.

2. The tropical Candida albicans strain HWDY-JD-001 as described in claim 1, characterized in that, The nucleotide sequence of the 18S rDNA of the strain is shown in SEQ ID NO.

1.

3. A microbial agent, characterized in that, It was obtained by culturing Candida tropicalis HWDY-JD-001 as described in claim 1, and the culturing method is as follows: (1) Slant culture: The strain of Candida tropicalis HWDY-JD-001 was inoculated into PDA slant medium and cultured at 28-32℃ for 24-48 h to obtain slant seeds; (2) Seed culture: The slant seeds were inoculated into the seed culture medium and cultured with shaking at 28-32℃ and 150-200 r / min for 18-24 h to obtain the seed culture; (3) Fermentation scale-up culture: The seed liquid is inoculated into the fermentation medium of the fermenter at an inoculation amount of 5-10 VT% for scale-up culture. The culture conditions are: 28-32℃, pH 6.5-7.2, tank pressure 0.05 MPa, DO control ≥20%, fermentation cycle 24-30h, to obtain the inoculum.

4. The microbial agent as described in claim 3, characterized in that, (1) The formula of the PDA slant culture medium is: 200 g / L potato, 20 g / L glucose, 15-20 g / L agar, 1000 mL distilled water, pH 6.8-7.

2.

5. A microbial agent as described in claim 3, characterized in that, (2) The seed culture medium formula is: glucose 10-20 g / L, peptone 5-10 g / L, yeast extract 3-5 g / L, NaCl 5 g / L, distilled water 1000 mL, pH 6.0-7.

0.

6. The microbial agent as described in claim 3, characterized in that, (3) The fermentation medium is: glucose 10-20 g / L, soybean meal 5-10 g / L, yeast powder 1-5 g / L, magnesium sulfate 0.3-0.5 g / L, potassium dihydrogen phosphate 0.5-1.0 g / L, dipotassium hydrogen phosphate 0.5-1.0 g / L, manganese sulfate 0.1-0.3 g / L, and polyether defoamer 1-2 g / L.

7. The application of the tropical Candida albicans HWDY-JD-001 as described in any one of claims 1-2 and / or the inoculum as described in any one of claims 3-6 in the degradation of aliphatic organic amines, wherein the aliphatic organic amines are selected from one or more of methylamine, dimethylamine, and triethylamine.

8. The application as described in claim 7, characterized in that, Application in the degradation of wastewater containing aliphatic organic amines.

9. The application as described in claim 7, characterized in that, The application method is as follows: The bacterial agent described in any one of claims 3-6 is added to wastewater containing aliphatic organic amines at a volume ratio of 1‰-5‰, and aerated for 24-72 h under the conditions of 10-40℃, pH 5.0-8.0, and dissolved oxygen ≥2 mg / L. The concentration of aliphatic organic amines in the wastewater ranges from 0 to 1500 mg / L.

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