Pseudomonas and application thereof in agricultural waste compost deodorization
By using *Pseudomonas nitroreductoids* XYT03 during the composting process to enhance the activities of urease and arylsulfatase, the problem of poor adaptability of deodorizing strains in existing technologies is solved, achieving efficient degradation of ammonia and hydrogen sulfide, and improving the quality and environmental friendliness of compost products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-04-07
AI Technical Summary
Existing technologies show that highly efficient deodorizing strains have poor adaptability and low stability in agricultural waste composting environments, making it difficult to simultaneously and efficiently degrade malodorous substances such as ammonia and hydrogen sulfide. Furthermore, existing methods pose risks of secondary pollution and are costly.
Nitroreducens Pseudomonas nitroreducens XYT03 was used as a microbial agent and inoculated into composting raw materials. Through a high-temperature aerobic composting process, it achieved efficient degradation of ammonia and hydrogen sulfide, enhanced the activity of urease and arylsulfatase, and optimized the biotransformation pathways of nitrogen and sulfur.
It significantly reduces the emission of ammonia and hydrogen sulfide during composting, improves the fertilizer efficiency of compost products, reduces operating costs, is environmentally friendly, causes no secondary pollution, and is highly adaptable.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of environmental microorganism technology and solid waste resource processing, and particularly relates to a Pseudomonas and application of the Pseudomonas in agricultural waste compost deodorization. BACKGROUND
[0002] Agricultural wastes, such as livestock and poultry manure, crop straw, mushroom residue and fruit and vegetable picking waste, contain rich organic matter and nutrient elements, and the resource utilization of the agricultural wastes through composting is one of the key ways for the sustainable development of current agriculture. However, in the process of aerobic composting, nitrogen-containing and sulfur-containing organic matter will decompose to produce a large amount of malodorous gas under the action of microorganisms, mainly including ammonia (NH3), hydrogen sulfide (H2S) and other nitrogen-containing and sulfur-containing volatile substances. These malodorous gases not only pollute the surrounding environment and harm human health, but also lead to the loss of nitrogen and sulfur nutrients in the composting process, reducing the fertilizer value of the final product.
[0003] At present, the common methods for controlling compost odor include physical adsorption, chemical washing and masking. Although the physical adsorption method can temporarily adsorb the odor components, the adsorption capacity is limited, and the adsorbent needs to be replaced or regenerated frequently, which has a high operation cost. The chemical washing method may introduce exogenous chemicals, which has the risk of secondary pollution, and the equipment and reagent cost is high. In addition, the above methods are all end-of-pipe treatments after the generation of odor, and cannot inhibit or reduce the generation of odor from the source.
[0004] Biological deodorization technology uses microbial metabolic activity to degrade or transform odor components such as NH3 and H2S, and has the potential of environmental friendliness, low cost and no secondary pollution, which is a more sustainable treatment method. However, the screening and application of high-efficiency deodorization functional strains are still the focus and difficulty of research, and the existing deodorization functional strains still have problems such as single function, poor adaptability and low stability in the actual composting environment. It is of great importance to find microbial strains that can simultaneously and efficiently degrade multiple odor substances and adapt to extreme environments such as high temperature and high salt in composting, for promoting the development of biological deodorization technology.
[0005] Therefore, the purpose of the present application is to provide a new and efficient Pseudomonas nitroreducens strain, which has the ability to simultaneously and efficiently remove ammonia and hydrogen sulfide, and can maintain activity in a wide temperature range, in order to solve the problems in the prior art. SUMMARY
[0006] The technical problem to be solved by the present application is to provide a Pseudomonas and application of the Pseudomonas in agricultural waste compost deodorization.
[0007] To solve the above technical problems, the present application adopts the following technical solutions: The present application first provides a Pseudomonas (Pseudomonas nitroreducens ) XYT03, which is preserved in the China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Yikhina Xilu, Chaoyang District, Beijing, China, on July 14, 2025, and has the preservation number CGMCC NO. 35224.
[0008] The application also provides an application of the Pseudomonas nitroreducens XYT03 in deodorization of agricultural waste compost.
[0009] Further, the agricultural waste includes at least one of livestock and poultry manure, crop straw, mushroom residue, or fruit and vegetable picking waste.
[0010] Further, the deodorization includes degradation of at least one of nitrogen-containing and sulfur-containing malodorous substances generated in the composting process.
[0011] Further, the Pseudomonas nitroreducens XYT03 is prepared into a microbial inoculant, and then the microbial inoculant is inoculated into compost raw materials.
[0012] Still further, the viable bacterial concentration of the Pseudomonas nitroreducens XYT03 in the microbial inoculant is 1x10 8 ~1x10 10 CFU / mL.
[0013] Still further, the addition amount of the microbial inoculant is 5‰-20‰ of the mass of the compost raw materials.
[0014] Still further, the microbial inoculant is inoculated into the compost raw materials for high-temperature aerobic composting, and the high-temperature period with a compost temperature exceeding 55℃ lasts for at least 5 days.
[0015] Compared with the prior art, the Pseudomonas nitroreducens XYT03 provided by the application can efficiently degrade ammonia, hydrogen sulfide, and other malodorous substances generated in the composting process, has high deodorization efficiency, strong environmental adaptability, and does not cause secondary pollution. The strain can be applied to the composting process of agricultural waste, can reduce the generation and emission of malodorous gases from the source, and has the advantages of low cost, simple operation, and green environmental protection. BRIEF DESCRIPTION OF DRAWINGS
[0016] The application will be further described below with reference to the accompanying drawings and embodiments.
[0017] Figure 1 The figure is a morphological diagram of Pseudomonas nitroreducens on a culture medium. DETAILED DESCRIPTION
[0018] The application provides a Pseudomonas nitroreducens strain XYT03. Pseudomonas nitroreducensXYT03, a Pseudomonas nitroreducens, is isolated and purified from a pig manure compost sample in Fuqing City, Fujian Province, and is a bacterial strain with the characteristic of removing compost odor.
[0019] The culture medium and solution involved in the strain screening of the present application are as follows: (1) Enrichment medium (g·L⁻¹): Na2S2O3·5H2O 5.0, KNO3 2.0, NaHCO3 1.0, MgCl2·6H2O 0.2, KH2PO4 2.0, pH 7.0, sterilized at 121 ℃ for 20 min; Na2S2O3·5H2O is added after sterilization by filtration.
[0020] (2) BTB primary screening solid culture medium (g·L⁻¹): KNO3 1.0, disodium succinate 8.5, KH2PO4 1.0, FeSO4·7H2O 0.14, MgSO4·7H2O 0.59, bromothymol blue (1% ethanol) 1 mL, agar 20, pH 7.0.
[0021] (3) Denitrification performance verification medium (g·L⁻¹): KNO3 1.08, CH3COONa 4.1, K2HPO4·3H2O 6.26, KH2PO4 1.24, MgSO4 0.2, trace elements 1 mL, pH 7.0.
[0022] The strain screening steps are as follows: Step 1: 3 g of sample is added to 100 mL of enrichment medium with glass beads, and the mixture is shaken at 200 r·min⁻¹ for 5 min. -1 35 ℃ for 5 d; Step 2: 1 mL of the enrichment bacterial solution is taken into a culture bottle containing 9 mL of sterile water to form a 10 -1 dilution solution, which is sequentially diluted to 10 -5 , 10 -3 , and 10 -5 , respectively. The 1 mL of microbial dilution suspension is inoculated into the screening medium, sealed, and placed in a 35°C biochemical incubator for static culture for 3-7 d. Step 3: The obtained strain is inoculated into BTB solid culture medium, sealed, and placed in a 35°C biochemical incubator for static culture for 3-7 d. Step 4: The enrichment culture producing a blue halo is subjected to plate streaking separation, the growth of the colonies is observed with the naked eye, different morphological single colonies are selected, and the plate streaking separation is continued on a new separation and purification culture medium until a pure strain with consistent colony characteristics is cultured. Step 5: Inoculate the isolated pure bacterial strain into a liquid culture medium containing denitrification performance verification and shake it to observe the growth of the strain. Select the strains with better growth, preserve them and conduct performance tests. The strain with the highest denitrification performance is selected as the target strain and then identified.
[0023] Genomic DNA was extracted from the pure culture of the strain, and PCR amplification and sequencing were performed using universal primers 27f and 1492r. A phylogenetic tree was then constructed using the Neighbour-Jioning method with Clustal X and Mega 11.0 software. The results showed that the strain belongs to Pseudomonas (…). Pseudomonas sp.), named Nitroreducing Pseudomonas (sp.), Pseudomonas nitroreducens XYT03 is deposited at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences. The deposit date is July 14, 2025, and the accession number is CGMCC NO. 35224.
[0024] The bacterial characteristics of this nitro-reducing Pseudomonas species are described below: 1. Morphological characteristics Nitroreducing Pseudomonas Pseudomonas nitroreducens XYT03 was observed to form circular bacterial communities after being cultured on LB medium at 35°C for 24 hours. Figure 1 The strain is rod-shaped. Gram staining of this strain revealed it to be a Gram-negative bacterium.
[0025] 2. Physiological and biochemical reaction characteristics Strain XYT03 is a Gram-negative bacterium without autonomous motility. Its optimal growth pH range is 6.0–7.5, and its optimal growth temperature is 25–35℃; growth is significantly inhibited in media with NaCl concentrations higher than 3%. Enzyme activity assays showed that this strain was positive for both catalase and oxidase, produced hydrogen sulfide, and showed a positive methyl red (MR) reaction (Table 1).
[0026] Table 1 Enzyme activity characteristics of strains +: indicates a positive reaction; -: indicates a negative reaction.
[0027] The results of antibiotic resistance testing showed that the strain was resistant to ampicillin and rifampin (Table 2).
[0028] Table 2 Antibiotic resistance of strains R: indicates resistance, S: indicates sensitivity
[0029] 3. Strain deodorization and metabolic function characteristics The XYT03 strain drives the biochemical conversion path of nitrogen and sulfur elements from the source by directing the metabolic function of the compost microbial community, thereby achieving fundamental reduction of malodorous gases and efficient immobilization of nutrient resources.
[0030] 3.1 Formulation characteristics The strain XYT03 has excellent fermentation adaptability and is easy to be industrialized. Under optimized liquid fermentation conditions, the viable cell concentration of the fermentation broth can stably reach 1×10 9 CFU / mL. Specifically, the liquid fermentation conditions include: inoculating the activated XYT03 seed liquid into R2A medium at an inoculation amount of 2% to 5%, and oscillating culture at 150 to 220 rpm under the condition of 28°C and pH 6.5 to 7.5 for 36 to 48 hours. After fermentation, the bacterial cells are collected by centrifugation, and can be resuspended with sterile physiological saline or a protective agent matrix (such as a buffer solution containing glycerol or trehalose), and then prepared into a stable liquid bacterial agent with a viable cell concentration in the range of 1×10 8 ~1×10¹ 0 CFU / mL.
[0031] 3.2 Composting effect In a preferred embodiment of the present application, the composting system is a high-temperature aerobic composting system, using pig manure and straw as raw materials at a mass ratio of 4:1, adjusting the initial carbon-nitrogen ratio (C / N) to 25:1, and controlling the initial moisture content at 60% to 65%, and carrying out composting in a 50L forced aeration reactor for 45 days. The compost temperature exceeds 55°C for at least 5 days in the high-temperature period to meet the harmless requirements.
[0032] The liquid XYT03 bacterial agent with a viable cell count of 1×10 9 CFU / mL is inoculated into the composting system at a proportion of 5‰ of the total mass of the composting raw materials, and high-temperature aerobic composting is carried out with no strain inoculation as a control.
[0033] Under this composting condition, the inoculation of the XYT03 bacterial agent significantly improves the key enzyme activities in the system. As shown in Table 3, the urease and aryl sulfate esterase activities of the test group are continuously higher than those of the control group throughout the process. By the 12th day of composting, the urease activity of the test group reaches 2.85 mg / g·d, and the aryl sulfate esterase activity reaches 1.42 mg / g·h, which are significantly higher than the control group of 1.98 mg / g·d and 0.88 mg / g·h, respectively. The synergistic enhancement of these two key enzymes is the core biochemical mechanism for achieving source reduction of malodorous gases.
[0034] Specifically, the enhancement of urease activity accelerates the process of urea hydrolysis into ammonium nitrogen, on the one hand, promoting the assimilation and fixation of nitrogen to microbial biomass, on the other hand, providing sufficient substrate for nitrification, thereby effectively reducing the accumulation and volatilization of free ammonia. The strengthening of this metabolic pathway is directly reflected in the 65.3% ammonia emission reduction rate on the 12th day of composting. Simultaneously, the increase in arylsulfatase activity drives the mineralization process of organic sulfur esters, efficiently converting organic bound sulfur into plant absorbable sulfate, thereby reducing the generation of hydrogen sulfide precursors, resulting in a hydrogen sulfide emission reduction rate of up to 68.9% during the same period.
[0035] More importantly, the XYT03 strain, through the above metabolic pathways, achieves significant improvement in the fertilizer efficiency of the compost product while deodorizing. As shown in Table 4, inoculation with the XYT03 microbial agent effectively improves the nutrient content and agricultural quality of the compost product. Specifically, in terms of nitrogen nutrients, the total nitrogen content of the inoculation group reaches 3.19%, and the nitrogen retention rate is 105.6%, which is significantly higher than that of the control group (2.52%, 83.3%), successfully reversing the nitrogen loss trend of conventional composting; at the same time, the nitrate nitrogen content in the finished product (215 mg / kg) is significantly higher than that of the control group (110 mg / kg), indicating that the nitrogen form is more optimal and more conducive to plant absorption. In terms of sulfur nutrients, the total sulfur content of the inoculation group (0.179%) is higher than that of the initial material, and the composting process effectively converts sulfur elements into stable sulfate forms. Finally, the seed germination index (GI) of the inoculation group is as high as 95%, far exceeding the control group (75%) and the 80% maturity standard, proving that the product has low phytotoxicity, high maturity, and high agricultural safety.
[0036] In summary, the strain XYT03 optimizes the biological conversion and immobilization pathways of nitrogen and sulfur elements in the composting process by synergistically enhancing urease and arylsulfatase activities, simultaneously achieving source emission reduction of malodorous gases and comprehensive improvement of the fertilizer efficiency and quality of the compost product.
[0037] Table 3 Effect of inoculation with XYT03 microbial agent on key enzyme activities and deodorization effect during composting
[0038] Table 4 Comparison of fertilizer efficiency indicators of compost products
[0039] 4. Environmental adaptability characteristics The optimal growth temperature of strain XYT03 is 25-35°C, and it can still maintain metabolic activity at high temperature of 50°C; the optimal growth pH is 6.0-7.5, and it can tolerate alkaline environment with pH 8.5; it grows well under the condition of NaCl concentration ≤3%. These characteristics ensure its stable deodorization performance in the temperature, pH, and salinity fluctuations during composting.
[0040] 5. Application effect characteristics Through multi-batch compost application tests, it is proved that the strain XYT03 inoculant shows stable and efficient deodorization effect and maturity promotion effect on various types of agricultural waste.
[0041] The specific application conditions are: liquid XYT03 inoculant with a viable bacterial count of 1×10 9 CFU / mL is inoculated into different formula compost systems at a ratio of 5‰ to 20‰ of the total mass of the compost raw materials (see Table 5), and high-temperature aerobic composting is carried out. After composting, the water extract of the compost product (solid-liquid ratio 1:10, w / v) is taken, and the cucumber seeds specified in the "Agricultural Industry Standard of the People's Republic of China NY525-2021" are used as test seeds, and the seed germination index (GI) is determined according to the standard method. The results show (see Table 5) that compared with the control group without inoculation, the ammonia cumulative emission of the treatment group inoculated with XYT03 inoculant is reduced by 69.8%~81.5%, and the hydrogen sulfide cumulative emission is reduced by 65.4%~78.9%. At the same time, the final seed germination index (GI) of all treatment groups is stable at 80.1%~88.9%, which is significantly higher than that of the control group, fully meeting the maturity standard of agricultural organic fertilizer (GI≥70%), proving that the compost product is low in plant toxicity and high in safety.
[0042] Table 5 Deodorization effect of strain XYT03 on different agricultural waste composts
[0043] Although the specific embodiments of the present application are described above, those skilled in the art should understand that the specific examples described are only illustrative, and are not intended to limit the scope of the present application, and equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present application should be covered within the scope of the claims of the present application.
Claims
1. A strain of Pseudomonas, characterized by: The pseudomonads mentioned are nitroreducing pseudomonads ( ). Pseudomonas nitroreducens XYT03, this strain is deposited at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences. The deposit date is July 14, 2025, and the accession number is CGMCC NO.35224.
2. The application of the nitro-reducing Pseudomonas as described in claim 1 in the deodorization of agricultural waste composting.
3. The application according to claim 2, characterized in that: The agricultural waste includes at least one of pig manure, mushroom residue, cow manure, crop straw, and fruit and vegetable harvesting waste.
4. The application according to claim 2, characterized in that: The deodorization process includes the degradation of nitrogen-containing and sulfur-containing odorous substances.
5. The application according to claim 2, characterized in that: Nitro-reducing Pseudomonas XYT03 was prepared as a microbial agent, and then the microbial agent was inoculated into compost raw materials.
6. The application according to claim 5, characterized in that: The viable concentration of *Pseudomonas nitroreductoids* XYT03 in the microbial agent was 1 × 10⁻⁶. 8 ~1×10 10 CFU / mL.
7. The application according to claim 5, characterized in that: The amount of microbial inoculant added is 5‰-20‰ of the mass of the compost raw materials.
8. The application according to claim 5, characterized in that: The microbial agent is inoculated into the composting raw materials for high-temperature aerobic composting, wherein the high-temperature period with the compost temperature exceeding 55°C lasts for at least 5 days.