Analysis Of Microbial Community Structure In Taozi Lake And Isolation And Identification Of Organic Pollutant-Degrading Bacteria

Organic pollutants are an important part of environmental pollution.They often have accumulation,migration and biological toxicity.Excessive accumulation of environmental organic pollutants will cause serious harm to human health and the environment.Compared with traditional physical remediation and chemical remediation,bioremediation represented by microbial remediation has the characteristics of green environmental protection and low cost,and has been favored by more and more researchers.Therefore,it is of positive significance to explore the microbial strains with the potential to repair organic pollutants in the environment for enriching microbial resources and realizing the efficient bioremediation of organic pollutants.In this study,Taozi Lake with organic pollution deposits was used as the sampling point,and 16 S rDNA high-throughput sequencing technology was used to study the diversity and composition of microbial communities in Taozi Lake.The organic pollutant degrading bacteria in the environmental samples of Taozi Lake were isolated and identified by enrichment and separation technology.Aiming at the isolated Sphingobacterium mizutaii GEMB-CSS-01,the degradation ability of some typical environmental organic pollutants was deeply studied,and its effect on the hormone disruptor 17β-estradiol(E2),and the degradation characteristics and the degradation ability of E2 under the sulfonamide/E2 composite pollution system was investigated.The results of the study are as follows:(1)Through 16 S rDNA high-throughput sequencing,the α-diversity,β-diversity and microbial community composition of Taozi Lake were explored.There are some differences in microbial diversity at different sampling points.Proteobacteria is the best bacteria phylum in the polluted sediment of Taozi lake,and the dominant bacteria genera include Draconibacterium、Neptuniibacter、Rhodopirellula、Desulfobulbus、Thiobacillus、Acidobacteria-Gp6、Geobacter、Acidobacteria-Gp17.The prediction of microbial function showed that the microbial community in Taozi Lake may be closely related to sulfur metabolism and nitrogen metabolism.(2)Two strains that could grow in medium containing high concentration of sulfonamide/bisphenol A were screened by enrichment separation technology,and named GEMB-CSS-01 and GEMB-CSS-02 respectively.After morphological observation,physiological and biochemical identification and 16 S r RNA gene identification,GEMB-CSS-01 was preliminarily identified as Sphingobacterium mizutaii,named Sphingobacterium mizutaii GEMB-CSS-01;GEMB-CSS-02 was Pseudomonas aeruginosa,named Pseudomonas aeruginosa GEMB-CSS-02.(3)In-depth study of the degradation ability of Sphingobacterium mizutaii GEMB-CSS-01 on some typical environmental organic pollutants.Studies have found that it has a good removal effect on hormone disruptor 17β-estradiol(E2),and can remove 80% E2 of 10 mg/L within 10 days.CSS-01 has a very high tolerance to sulfanilamide.Compared with the control group,the biomass can still be 60% at a concentration of 700 mg/L sulfanilamide.At the same time,the removal efficiency of E2 can still reach 40% in the sulfonamide-estrogen E2 compound pollution system.The development of research can further enrich environmental microbial resources,and provide valuable new information for further exploring the remediation potential of microbial organic pollutants and realizing the wide application of microbial remediation technology in the field of organic pollution remediation.