Identification Of Strain XM-4 And Analysis Of Its Agricultural And Environmental Remediation Functions

In this study,a strain of bacteria XM-4 selected from the soil was used as the research object to identify the strain and analyze the functions of agricultural and environmental remediation.1.The morphological observation and 16S rRNA sequencing were used to identify the strain XM-4 as Bacillus subtilis.2.Through the plate confrontation experiment,it was proved that the strain XM-4 can effectively inhibit mycelia growth of Fusarium graminearum,Fusarium moniliforme,Curvularia lunata,Fusarium oxysporum,Pestalotiopsis theae,and Colletotrichum lagenarium.And the inhibition rate was over 60%.The fermentation broth of the strain XM-4 in a stable period was extracted,and the sterile fermentation broth was obtained through two processes of filter sterilization and autoclaving.The experiments proved that the sterile fermentation broth obtained by the two treatments showed basically the same antagonistic effects on six pathogenic fungi,.The diameter ratio of the cellulolytic transparent circle and the colony of strain XM-4 was determined to be 3.6 by plate experiment.Quantitative analysis by CMCase method and FPase method showed the strain XM-4 sterile fermentation broth reached the highest cellulase activity 203.74 U/mL and 172.66 U/mL,respectively,on the 3rd day.The removal rate of DPPH free radicals by the fermentation broth of strain XM-4 on day 4 reached as high as 80%.At the same time,the strain XM-4 has the functions of dissolving potassium and fixing nitrogen by the plate qualitative experiment.3.Strain XM-4 was inoculated on solid LB medium containing different concentrations of bisphenol S respectively.The results showed that the maximum tolerance concentration of strain XM-4 to bisphenol S was 300 mg/L.The peak area corresponding to different concentrations of bisphenol S standard solution was detected by high performance liquid chromatography,and the regression equation of bisphenol S obtained by fitting the data was y=63.608x-48.846,R~2=0.9996.The strain XM-4was inoculated into an inorganic salt liquid medium with a bisphenol S content of 60mg/L in a constant temperature shake flask culture.The degradation rate of bisphenol S by strain XM-4 for 6 consecutive days was detected by high performance liquid chromatography.The results showed that the highest degradation rate of bisphenol S by strain XM-4 on 6th day was 80.82%.4.The metabonomics of XM-4 in normal culture and xm-4 in bisphenol s culture were detected and analyzed After analyzing 12 experimental samples,a total of ten categories and 325 kinds of metabolites were identified.Through univariate statistical analysis,47 different metabolites were found.Then,eight key metabolic pathways were screened by metabolic pathway analysis of different metabolites.Finally,it was found that the metabolic pathways of D-arginine and D-ornithine were the key pathways with the highest correlation with the differences of metabolites of XM-4.This study proves that the strain XM-4 is a multifunctional strain with agricultural and environmental remediation functions,which will lay a foundation for the development of biological fertilizer and environmental remediation agents.