Screening, Identification And Application Of Antimony-resistant Microorganisms

With the mining activities such as antimony mining and the more and more extensive application of antimony in modern society,the output of antimony ore has increased rapidly and become the ninth largest mineral in the world.As the largest antimony reserve and production country in the world,in the mining and application of antimony ore,a large number of antimony enters the environment,causing serious environmental antimony pollution,and antimony has the characteristics of carcinogenicity and global migration.Therefore,how to remove it from the environment needs to be solved urgently.The technology of antimony removal by microbial adsorption has the advantages of extensive source of crude materials,low cost,safety and economy,wide application range and no secondary pollution.It has been widely concerned by researchers in the field of wastewater heavy metal treatment.Heavy metals will accumulate in crops and pose a threat to human body through the food chain.Therefore,it is important for us to probe how to reduce the accumulation of antimony in crops in antimony contaminated soil.In this study,two antimony resistant strains were isolated from the soil of the mining area and identified;Study its physiological and biochemical characteristics;The ability of the strain to adsorb and remove antimony was explored,and the effects of different inoculation amount,initial antimony concentration,absorption time and p H on the absorption of antimony by anti antimony strains were investigated;In the hydroponic experiment,the effects of antimony resistant strains on plant growth under antimony stress were compared between inoculated and non inoculated.The results are as follows:(1)Among the two antimony resistant strains screened on LB medium,strains X14 and X16 belong to Bacillus aryabhattai and Bacillus megaterium,respectively.They are named as Bacillus aryabhattai X14 and Bacillus megaterium X16,respectively,all of which were Gram-positive bacteria.(2)The physiological and biochemical characteristics of the two strains showed that strains X14 and X16 had the ability to produce indoleacetic acid(IAA),and their yields were2.01?g·m L^-1?2.78?g·m L^-1respectively;The quantitative test of iron carrier showed that strains X14 and X16 could not only produce iron carrier,but also their iron carrier yields were56 and 52.51 respectively;At the same time,both strains have the ability to produce ammonia,indole and hydrolyze starch.(3)In the experiment of exploring the effects of different conditions on the adsorption of antimony by strain,it was found that the best conditions for the adsorption of trivalent antimony ions by strain X14 were:inoculation amount of 2%,initial concentration of Sb³⁺4.0mg/L,p H=6.0,adsorption time of 2 h.For strain X16,the optimum conditions for adsorption of trivalent antimony ions were as follows:inoculation amount 2%,initial concentration of Sb³⁺4.0 mg/L,adsorption time 1.5 h,p H=7.0.(4)Through the analysis of the infrared spectra of strains x14 and x16 before and after the adsorption of Sb,although there are some differences in the absorbance of the infrared spectra of strains before and after the adsorption of heavy metals,there is no new absorption peak,and the peak type has not changed,which shows that the bacteria have not been damaged in the whole adsorption process.And it can also illustrate that this process is surface adsorption,and some active groups on the cell surface are the main participants.(5)The effects of two antimony resistant strains on the growth of Maize under antimony pollution were analyzed.The results showed that the two strains evidently increased the biomass of maize plants,promoted the growth of maize plants,and reduced the toxicity of antimony to maize under antimony stress.Antimony resistant strains have a certain effect on the mitigation of antimony toxicity,which also provides an effective strategy for alleviating the harm of antimony toxicity in soil in the future,and has practical application value for promoting the growth of local vegetation and alleviating the toxicity of plants to heavy metals.