Microbial Diversity And Isolation And Identification Of Antimony Oxidizing Bacteria In Antimony Polluted River Sediment

Antimony is a toxic metalloid.With the development of China’s mining industry,antimony mining will cause serious antimony pollution in the surrounding environment.Antimony pollution in river sediment will produce secondary release,which has a long-term impact on the surrounding ecological environment and human health.Microorganisms are one of the main drivers of antimony biogeochemical cycling in rivers.Antimony oxidizing bacteria can convert Sb(III)into Sb(V)with low toxicity and high migration,which plays an important role in the remediation of antimony pollution in river sediment.In order to analyze the microbial community structure and antimony oxidation process of river sediment under antimony pollution,this study took antimony-polluted river sediment in Dushan County,Guizhou as the research object,combined with geochemical parameter analysis,high-throughput sequencing and statistical analysis,to elucidate the microbial community structure characteristics of river sediment under antimony pollution,and reveal the potential microorganisms of antimony transformation.Combined with DNA-SIP technology and microcosmic simulation experiments,the antimony oxidation process in river sediment was verified and antimony oxidizing microorganisms were identified.The purification and separation of antimony oxidizing microorganisms by traditional microbiological methods provides a basis for the study of microbial-mediated antimony cycling and the ecological restoration of antimony oxidizing strains.The main conclusions are as follows:(1)Antimony drives changes in the microbial community structure of river sediment.With the increase of migration distance,the content of antimony in river sediment showed a gradual decrease trend.Antimony is the main factor driving the change of microbial community structure in river sediment,significantly reducing the diversity of microorganisms.(2)High antimony environment shaping regulates the composition of antimony cyclic microorganisms.The high antimony contaminated area is enriched with microorganisms such as Paludibacter,Clostridium＿sensu＿stricto＿1,Trichococcus,and Saccharofermentans.Microorganisms positively correlated with antimony in river sediment encode functional genes associated with antimony resistance.Paludibacter,Erysipelothrix,Desulfovibrio and others were identified as potential antimony reducing bacteria in river sediment,and Mesorhizobium as potential antimony oxidizing bacteria.(3)Identification of key antimony oxidizing bacteria in river sediment.The biological oxidation process of antimony in river sediment was revealed.Rhizobium,Hydrogenophaga,Thiobacillus,and Gemmobacter play an important role in the oxidation of antimony.Through functional prediction,it was shown that these microorganisms had rich antimony resistance functional genes,among which antimony oxidation functional genes were identified in Rhizobium and Hydrogenophaga,indicating that they had a key role in the antimony oxidation process.(4)The isolated and purified antimony oxidizing bacteria have strong antimony oxidation and antimony tolerance ability,and are named Rhizobium sp.S1,which has an oxidation rate of 11.47μM/h for antimony and a tolerance concentration of 50 m M for both Sb(III)and Sb(V).Pan-genome showed that various Rhizobium members obtained from different environments contained functional genes related to antimony resistance and antimony oxidation,revealing the antimony metabolism potential of Rhizobium members in different environments.