Enrichment of 1,2-dichloroethane Degrading Bacterial Consortium,and Isolation and Identification of Ancylobacter sp.BL0 of a Key Degrading Bacterial Strain
[Objective]The pollution of 1,2-dichloroethane(1,2-DCA)will seriously harm human health and environmental ecological safety.In order to obtain efficient 1,2-DCA biodegrading microorganism resources,the characteristics of bacterial flora were studied,and then the rules and methods for separating and screening efficient 1,2-DCA degrading strains were explored.[Method]The bacteria utilizing 1,2-DCA as the sole carbon source and energy were enriched and cultured from soil contaminated by 1,2-DCA.The growth of bacteria and degradation of 1,2-DCA in different batches were investigated by ultraviolet spectrophotometry and gas chromatography respectively.The species diversity and relative abundance of different enriched solution were analyzed by high-throughput sequencing.The strain was identified by 16S rDNA gene sequence analysis.The degraded products were determined by gas chromatography-mass spectrometry,and the degradation pathway was analyzed.[Result]Bacterial consortium BG1 for degradation was gained,and the experimental results showed that the degrading rate of 12.5 mg/L 1,2-DCA by enriched bacterial consortium in batch 6-11 and 15 increased at the beginning and then decreased within 24 h,and the microbial biomass(OD600)increased from 0.03 to 0.095,but the relative abundance of Ancylobacter sp.in the flora decreased with continuous enrichment process.A strain named BL0 was screend from the batch 9 of enrichment solution and identified as Ancylobacter sp.,which degraded 120 mg/L 1,2-DCA within 6 h.It was inferred that the metabolic pathway of degradation of 1,2-DCA by BL0 was hydrolysis of 1,2-DCA to 2-chloroethanol at first,and 2-chloroethanol was oxidized to chloroacetic acid,which was then completely degraded and utilized.[Conclusion]Highly efficient 1,2-DCA degrading bacterial consortium BG1 and strain Ancylobacter sp.BL0 are obtained,and it is found that a long period of sample enrichment is required for screening and separation of 1,2-DCA degrading strains during the process of sample enrichment and low microbial growth is observed,which is not suitable for over-enrichment.Strain Ancylobacter sp.BL0 is competitive with the other strains in the enrichment of bacterial consortium.
1,2-dichloroethanebiodegradationenrichment of bacterial consortiumdegrading consortiumAncylobactercommunity interactionmetabolic pathway
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