Diversity and Dynamics of Microbial Community Structure in Different Mangrove, Marine and Freshwater Sediments During Anaerobic Debromination of PBDEs

Abstract

Little is known about the diversity and succession of indigenous microbial community during debromination of polybrominated diphenyl ethers (PBDEs). This study examined the diversity and dynamics of microbial community structure in eight saline (mangrove and marine) and freshwater sediment microcosms exhibiting different debrominating capabilities for hexa-BDE 153, a common congener in sediments, using terminal restriction fragment length polymorphism (T-RFLP) and clone library analyses. The results showed that microbial community structure greatly differed between the saline and freshwater microcosms, likely leading to distinct variations in their debrominating capabilities and pathways. Higher relative abundances of Chloroflexi and Deltaproteobacteria succeed by Alphaproteobacteria and Betaproteobacteria were detected in the two mangrove microcosms with the fastest debrominating capabilities mainly via para pathway, respectively; the dominance of Alphaproteobacteria resulted in less accumulation of tetra-BDEs and more complete debromination of lower brominated congeners (from di- to tetra-BDEs). Meanwhile, the shifts in both microbial community structure and PBDE profiles were relatively small in the less efficient freshwater microcosms, with relatively more ortho and meta brominated products of BDE-153 resulted. Coincidently, one of the freshwater microcosms showed sudden increases of Chloroflexi and Deltaproteobacteria by the end of incubation, which synchronized with the increase in the removal rate of BDE-153. The significant relationship between microbial community structure and PBDEs was confirmed by redundancy analysis (18.7% of total variance explained, P = 0.002). However, the relative abundance of the well-known dechlorinator Dehalococcoides showed no clear correlation with the debrominating capability across different microcosms. These findings shed light in the significance of microbial community network in different saline environments on enhancement of PBDE intrinsic debromination.

Recent Advanced Technologies for the Characterization of Xenobiotic-Degrading Microorganisms and Microbial Communities

“…The combined use of metabolomics with these applications details the authentic collection of chemical outputs and inputs, which arbitrate the exchange of resources between the community and its host ( Table 4 ; Theriot et al, 2014 ; Wang Y. F. et al, 2018 ). Metabolomic studies in environmental sciences have been directed toward understanding changes in the concentration of metabolites associated with exposing model organisms to toxic compounds, such as xenobiotics (Parisi et al, 2009 ; Seo et al, 2009 ).…”

“…Microbial remediation of xenobiotic compounds is regarded as a superficial, proficient, economically feasible approach that uses a wide range of microorganisms to consume organic pollutants as carbon or nitrogen supplements to sustain their developmental activities (Chen et al, 2013 ; Mahmoud, 2016 ; Arora et al, 2018 ; Ortiz-Hernandez et al, 2018 ; Siles and Margesin, 2018 ; Zhan et al, 2018 ; Bhatt et al, 2020b ). Microorganisms are ubiquitous in nature, and diverse microbial communities thrive in natural and extreme stress environments, including soil, water, the human gut, hydrothermal vents, acid mine runoff, and oil reservoirs (Cycoń and Piotrowska-Seget, 2016 ; Jalowiecki et al, 2016 ; Ding et al, 2017 ; Aguinga et al, 2018 ; Wang Y. F. et al, 2018 ; Zierer et al, 2018 ; Delegan et al, 2019 ; Arora, 2020 ; Shekhar et al, 2020 ). Microbial populations exhibit potential for the remediation of any contaminated environment because of their genetic diversity and functionality (Chen et al, 2015 ; Bastida et al, 2016 ; Bhatt and Barh, 2018 ; Dangi et al, 2018 ).…”

Molecular Methods as Potential Tools in Ecohydrological Studies on Emerging Contaminants in Freshwater Ecosystems

“…HTS analysis of 16S rDNA fragments was also used in combination with T-RFLP and qPCR to assess the diversity and dynamics of bacterial communities in saline and freshwater sediments during anaerobic debromination of polybrominated diphenyl ether [65]. The findings indicate that both the microbial community structure and dynamics are determined by the debrominating properties of the studied sediment.…”

Transcriptome Profiling of Stenotrophomonas sp. Strain WZN-1 Reveals Mechanisms of 2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47) Biotransformation

“…11 The main pathway of anaerobic degradation of PBDEs is debromination of high brominated diphenyl ethers to low brominated diphenyl ethers via various reductases and dehalogenases. 14,15 Compared with anaerobic microbial degradation, aerobic microbial degradation has a faster rate and can achieve complete mineralization. 16 To date, several aerobic microorganisms have been reported to degrade BDE-47, including Pseudomonas aeruginosa YH, Stenotrophomonas maltophilia, Brevibacillus brevis, and Enterococcus casseliflavus.…”

“…Microbial degradation of PBDEs has been previously examined under both anaerobic and aerobic conditions . The main pathway of anaerobic degradation of PBDEs is debromination of high brominated diphenyl ethers to low brominated diphenyl ethers via various reductases and dehalogenases. , Compared with anaerobic microbial degradation, aerobic microbial degradation has a faster rate and can achieve complete mineralization . To date, several aerobic microorganisms have been reported to degrade BDE-47, including Pseudomonas aeruginosa YH, Stenotrophomonas maltophilia , Brevibacillus brevis , and Enterococcus casseliflavus . − Studies to date have predominantly focused on the screening of highly efficient strains, degradation characteristics and degradation pathways, as well as the enhancement effect of surfactants to improve the degradation efficiency.…”