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CN-122012277-A - Biochar-based azotobacter microbial agent and preparation method and application thereof

CN122012277ACN 122012277 ACN122012277 ACN 122012277ACN-122012277-A

Abstract

The invention belongs to the technical field of microbial agents, and particularly relates to a biochar-based azotobacter agent, a preparation method and application thereof. The invention adopts the embedding mode of the biochar-humic acid-sodium alginate, can provide a porous protection cabin and can adsorb plant rhizosphere nutrients. Meanwhile, a low-oxygen micro-area protection nitrogen fixation enzyme is created, physical protection is provided for thalli, and external environmental stress is buffered. Wherein, humic acid is used as a high-quality organic carbon source, which is helpful for stimulating the quick proliferation of thalli in embedded particles and rhizosphere, and can obtain a large number of active cells in a short time. The biochar-based azotobacter microbial agent (namely the biochar-humic acid-sodium alginate microspheres) prepared by the invention has the advantages of simple preparation method, stable storage performance and the like, and compared with other biological agents, the biomass of the microbial agent after being dried reaches 2.2 multiplied by 10 10 CFU/g, and has good application prospect.

Inventors

  • XUE YAPING
  • ZOU SHUPING
  • CHEN ZHOUQIANG
  • ZHENG YUGUO

Assignees

  • 浙江工业大学

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. The biochar-based azotobacter microbial inoculum is characterized by comprising a diazotrophic gluconobacter mutant ZJB-2025351 adsorbed on biochar, wherein the diazotrophic gluconobacter mutant ZJB-2025351 is embedded by a mixed solution of humic acid and sodium alginate and is crosslinked and fixed through divalent metal ions.
  2. 2. The biochar-based azotobacter agent according to claim 1, wherein the diazotrophic glucose acetobacter mutant ZJB-2025351 has a preservation number of CCTCC NO: M20252292 and is preserved in China center for type culture Collection.
  3. 3. The biochar-based azotobacter agent according to claim 1, wherein the divalent metal ions are calcium ions.
  4. 4. The biochar-based azotobacter agent according to claim 1, wherein the diazonium nutrient type gluconacetobacter oxydans mutant ZJB-2025351 is at least one of bacterial powder, wet bacterial body and culture.
  5. 5. A method for preparing the biochar-based nitrogen-fixing bacteria agent according to any one of claims 1 to 4, comprising the following steps: S1, mixing a diazonium nutrient type acetobacter xylinum mutant culture with charcoal for adsorption and centrifuging to obtain the charcoal loaded with the diazonium nutrient type acetobacter xylinum mutant; S2, adding the biochar loaded with the diazonium nutrient type gluconacetobacter oxydans mutant obtained in the step S1 into a mixed solution of humic acid and sodium alginate for embedding to obtain embedded biochar; and S3, adding the embedded biochar obtained in the step S2 into a divalent metal ion solution for crosslinking and curing, filtering and washing to obtain the biochar-humic acid-sodium alginate microspheres, namely the biochar-based azotobacter microbial agent.
  6. 6. The preparation method of the biochar-based azotobacter fungus agent is characterized in that in the step S1, adsorption is carried out under the condition of water bath oscillation, the adsorption temperature is 20-30 ℃, the adsorption time is 20-40 min, and the oscillation rate is 30-180 r/min.
  7. 7. The preparation method of the biochar-based azotobacter agent, which is disclosed in claim 5, is characterized in that the addition amount of biochar in the step S1 is 3-8%, and the concentration of the diazonium nutrient type gluconacetobacter oxydans mutant culture is 1-9 multiplied by 10 9 CFU/mL.
  8. 8. The preparation method of the biochar-based azotobacter fungus agent, which is characterized in that the final concentration of humic acid in the mixed solution in the step S2 is 3-6 g/L, and the final concentration of sodium alginate is 2-8 g/L.
  9. 9. The method for preparing the biochar-based azotobacter according to claim 5, wherein the concentration of the divalent metal ion solution in the step S3 is 0.03-0.11 mol/L, and the crosslinking curing time is 20-60 min.
  10. 10. The use of the biochar-based nitrogen-fixing bacteria agent according to any one of claims 1 to 4 in plant growth promotion.

Description

Biochar-based azotobacter microbial agent and preparation method and application thereof Technical Field The invention belongs to the technical field of microbial agents, and particularly relates to a biochar-based azotobacter agent based on diazotrophic gluconacetobacter (Gluconacetobacter diazotrophicus) ZJB-2025351, and a preparation method and application thereof. Background Improper use of chemical fertilizers causes problems such as soil acidification, atmospheric nitrogen deposition, water quality deterioration, quality degradation of agricultural products, and nitrogen-phosphorus imbalance. The widespread use of Plant growth-promoting microorganisms (Plant growth-promoting microorganism) has been accepted as an effective alternative to chemical agricultural products for recent decades. Bacteria (PGPB) that promote plant growth are very promising agricultural green biological agents with effects of promoting plant growth and environmental stress, improving soil microbiology, and improving soil fertility. However, a significant challenge in using PGPB is the loss of cell viability under storage and harsh field conditions, where the effectiveness of PGPB is greatly affected by its loss of bioactivity and potency when injected directly into the soil. Therefore, there is a need to increase the survival rate of soil-introduced microorganisms and to enhance their growth promoting effect in cultivated crops. Currently, there are two areas of research focus on microbial immobilization technology. Firstly, the realization technology of the immobilized microbial inoculum, and secondly, the selection of immobilized carrier materials. The realization technology of the immobilized microbial inoculum mainly comprises an adsorption method, an embedding method, a crosslinking method, a covalent bonding method and the like according to different action modes of an immobilized carrier and cells. The adsorption method has the advantages of simple operation and high bacterial survival rate and is widely applied. Common immobilization carrier materials include alginate, agar, carrageenan, gelatin, sponge, polyvinyl alcohol, diatomite, kaolin, biochar, bran, straw, rice husk, coconut husk and the like, but few reports on endogenous nitrogen-fixing microorganisms exist. The biochar can be used as a slow release carrier of the strain, and the abundant pore structure and adsorption performance of the biochar can also improve the physical and chemical properties of soil, regulate the acidity and alkalinity of the soil, improve the utilization efficiency of nutrients and moisture, increase the abundance of soil microorganisms and increase the content of soil elements. Humic Acid (HA) is used as a high-quality organic carbon source, can stimulate the quick proliferation of thalli in embedded particles and rhizosphere, and can be cooperated with biochar to obviously improve the rhizosphere microecology. Sodium Alginate (SA) is a common material for preparing gel spheres, is nontoxic, easy to degrade and low in cost, and can interact with calcium and other divalent metal cations to prepare gel spheres for protecting microorganisms adsorbed on biochar. Therefore, the invention takes the biochar as a carrier, adopts an adsorption-embedding immobilization mode, takes plant endophyte-diazotrophic gluconacetobacter as an embedding object, and prepares the biochar-based composite immobilized microbial agent so as to ensure the long-term survival of beneficial microorganisms and improve the application performance of the beneficial microorganisms. Disclosure of Invention The invention provides a biochar-based azotobacter bacterial agent and a preparation method thereof, and the azotobacter bacterial agent is applied to plant growth promotion, aiming at overcoming the defects of instability and poor environmental adaptability of PGPB in the prior art when facing biotic stress and abiotic stress. In order to achieve the aim of the invention, the invention is realized by the following technical scheme: A biochar-based azotobacter microbial inoculum comprises diazotrophic gluconobacter mutant ZJB-2025351 adsorbed on biochar, wherein the diazotrophic gluconobacter mutant ZJB-2025351 is embedded by a mixed solution of humic acid and sodium alginate and is crosslinked and fixed through divalent metal ions. According to the invention, through further analyzing the complementary relation between the characteristics of the strain and the functions of the carrier, the biochar, the humic acid and the sodium alginate are organically combined, so that a new immobilized system capable of cooperatively improving the comprehensive performance of the nitrogen-fixing bacteria agent is developed. In carrier selection, the biochar is not only used as a physical adsorption matrix, but also has rich pore structures, so that a perching space is provided for thalli (namely, diazotrophic gluconacetobacter mutant ZJB-2025351), and meanwhile, rhizosphere nutrients