Biodegradation Of Tetrachlorobisphenol A (TCBPA) And Tetrabromobisphenol A (TBBPA) And Associated Microbial Community Change Based On 16S RRNA Gene High-Throughput Sequencing

Tetrachlorobisphenol A(TCBPA)and tetrabromobisphenol A(TBBPA)were widespread use of flame retardants and aroused extensive attention for the characteristics of endocrine disruptors and other adverse effects.Due to the c hemical stability and strong hydrophobicity,TBBPA and TCBPA were easily enriched in soil or sediment environment,especially in the e-waste dismantling area.In this research,we applied river sediment adjacent to an electronic waste dismantling area as culture medium to the degradation of TBBPA and TCBPA.The effects of different anaerobic conditions on dehalogenation efficiency and difference of bacteria communities in degrading process were investigated by Illumina 16 S r RNA gene Miseq sequencing.Furthermore,the aerobic degradation of the anaerobic dehalogenation end product BPA was also studied.The results indicated that debromination was more efficient than dechlorination under the identical condition and these processes could be promoted by adding electron donor.The performance of dehalogenation efficiency of TCBPA and TBBPA were of s imilarity under different anaerobic conditions,among which methanogenic condition exhibited the best dehalogenation promoting effect and followed by electronic donor enhanced condition and sulfate reducing condition.Moreover,lower concentration of sulfate availed to TCBPA dechlorination,while higher concentration of sulfate is more conducive to TBBPA debromination.Bacteria community diversity analysis revealed that the addition of TCBPA and TBBPA could lead to the reduction of population richness with the tendency of initial rise and subsequent decrease.Also both of the bacterial community assumed a similar composition under the same condition in the same periods of time.Taxonomic classification analysis showed that Proteobacteria,Chloroflexi,Firmicutes,Bacteroidetes,Actinobacteria,Planctomycetes and Nitrospirae were predominant strains in all sediments.And the relative abundance of Chloroflexi,Firmicutes and Bacteroidetes were remarkably increased.Unclassified Anaerolineaceae,Longilinea,Leptolinea,Anaerolinea,Bellilinea,Clostridium,Fastidiosipila,vadin BC27 wastewater-sludge group and unclassified Porphyromonadaceae were dominant genera that involved in dehalogenation of TCBPA and TBBPA showed certain augmentation in relative abundance.Geobacter,Desulfuromonas,and Desulfobulbus as sulfate reducing bacteria were identified to connect with lag time and lower dehaloge nation rate of target pollutants under sulfate reducing condition.The difference of samples added TCBPA or TBBPA was mainly reflected in methanogenic condition and its dominant cultures including Longilinea,Leptolinea,Bellilinea,Clostridium,Fastidiosipila,unclassified Porphyromonadaceae,Sphingopyxis and Sphingobium resulted in higher dehalogenation efficiency.