Screening, Separation And Identification Of NX-11Strain With The Abilitity Of Solubilizing Phosphate And Potassium And Analysis Of Effect Microbial Fertilizer

China is a nation with vast area, phosphorus and potassium in the soil is very difficultto use by plants. A large quantity of chemical fertilizers caused damage to the ecologicalbalance and environmental protection. And also, the agricultural development was affected.Biological fertilizer is characterized by innocuity, low cost, high efficiency andconomization of energy. This may make up for the disadvantages and limitations ofchemical fertilizer. The core issues of utilizating and developing microbial fertilizer is toscreen and separation high efficient strains.The study of crop pathogen antagonistic action exhibited by bacteria capable ofefficiently solubilizing phosphorus and potassium is very ordinary. In this study, the NX-11strain with high activity of solubilizing potassium, aimed to obtain multi functionalbacteria, which not only have efficient solubilization of phosphorus and potassiumcapabilities, but also exhibit the effect of biological control. And we also studies ofsolubilizing phosphorus and potassium strains on the colonization of the rhizosphere aswell as the influence on soil biological fertility, enzyme activity and phosphorus andpotassium nutrition. And through laboratory experiments we developed a type of highlyefficient microbial agents for the services of our country’s agricultural production.243bacillus stains were isolated from different crops soil samples in the country’sdifferent regions and34strains with the function of solubilizing or dissolving potassiumwere obtained using plate screening methods. Soluble phosphorus and potassium content inthe fermentation liquid was determined by Mo-Sb antispetrophotography method andsodium tetraphenylboron method, and the selected strains have higher phosphorus andpotassium solubilizing activity than the K-1strain (AC10012).3strains have efficientsolubilizing activity of organic phosphorus, which are NX-11、CX-14and BY-4.15strainshave efficient solubilizing activity of inorganic phosphorus bacteria, which are BY-3, CX-9,SS-14, SS-9, BY-4, CC-14, CX-7, CX-24, SS-8, NX-11, NX-42, CX-8, CX-21, SS-12andCC-34.12strains were be found to be high potassium dissolving bacteria, which areNX-11, NX-43, CX-9, CX-8, CX-7, BY-4, SS-12, NX-23, CX-14, BY-3, NX-12andNX-42. From the above34strains we screened5strains showed antagonistic behauioragainst pathogenic bacteria antagonistic. The NX-11strain, separated from sunflower soilin Neimeng, had high solubilizing capacity of phosphorus and potassium, and high antibacterial activity, so physiological and biochemical reactions and sequence analysis of16S rDNA gene were done. The physiological and biochemical reactions showed thefeatures of NX-11strain were similar to Paenibacillus kribbensis.16S rDNA sequencehomology comparison was done on the NCBI website, and the phylogenetic tree wasdrawn by the Neigllbor-Joining’s method. The results showed that16S rDNA sequencehomology of NX-11strain and Bacillus subtilis subsp. Subtilis at100%. Therefore,combining physiological and biochemical reactions and16S rDNA gene sequence analysis,NX-11strain was identified as Bacillus subtilis subsp. Subtilis.The phosphate and potassium solubilizing activity of Bacillus subtilis subsp. SubtilisNX-11strain were found to be organic phosphorus8.06mg/L, inorganic phosphorus62.35mg/L and potassium feldspar9.61mg/L. The results of the corn plant test inoculated withNX-11strain showed that: leaf area increased by5.6%, plant height increased by8%, wetand dry weight increased by21.6%and68.3%, available potassium and availablephosphorus content in the soil was higher than that of the control. Researches on soilphosphorus, potassium nutrient and enzyme activity of maize pot experiment demonstratethat sucrase can be increased by0.33mg/g, the catalase by0.40mg/g, the phosphatase by1.22mg/g, the urease activity by0.14mg/g; as well as potassium content is increased by29.5%, phosphorus content can be increased by122.2%, so it can improve the environmentof maize rhizsphere.NX-11strain has good application effect of solubilizing phosphorus and potassium,and has the very good development prospects.Liquid fermentation conditions of antimicrobial substances produced by the NX-11strain were optimized, the optimal culture medium of obtaining antibacterial proteins: Theresults showed that the optimal medial components were composed of5.0%starch,1.5%soybean cake powder,0.07%MgSO4,0.05%NaCl. The optimal culture conditions were attemperature37℃with initial pH8.0and incubation time20h, inoculum’s volume40mL/L, medium volume30mL in250mL flask and200r/min.