Compound degraded:Deca-brominated diphenyl ethers (BDE 209)

General Description (About POP compound)

Deca-brominated diphenyl ethers belongs to a wider group of polybrominated diphenyl ethers (PBDEs), a class of organobromine compounds that are used as flame retardants. Deca-brominated diphenyl ethers have been used in a wide array of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics, polyurethane foams,[1] and textiles. They are structurally akin to polychlorinated diphenyl ethers (PCDEs), polychlorinated biphenyls (PCBs) and other polyhalogenated compounds, consisting of two halogenated aromatic rings.

Biodegradation pathway

Publications

Abstract Title Authors Article Link
Polybrominated diphenyl ethers (PBDEs) have become widespread environmental pollutants all over the world. A newly isolated bacterium from an e-waste recycling area, Stenotrophomonas sp. strain WZN-1, can degrade decabromodiphenyl ether (BDE 209) effectively under aerobic conditions. Orthogonal test results showed that the optimum conditions for BDE 209 biodegradation were pH 5, 25 °C, 0.5% salinity, 150 mL minimal salt medium volume. Under the optimized condition, strain WZN-1 could degrade 55.15% of 65 ?g/L BDE 209 under aerobic condition within 30 day incubation. Moreover, BDE 209 degradation kinetics was fitted to a first-order kinetics model. The biodegradation mechanism of BDE 209 by strain WZN-1 were supposed to be three possible metabolic pathways: debromination, hydroxylation, and ring opening processes. Four BDE 209 degradation genes, including one hydrolase, one dioxygenase and two dehalogenases, were identified based on the complete genome sequencing of strain WZN-1. The real-time qPCR demonstrated that the expression level of four identified genes were significantly induced by BDE 209, and they played an important role in the degradation process. This study is the first to demonstrate that the newly isolated Stenotrophomonas strain has an efficient BDE 209 degradation ability and would provide new insights for the microbial degradation of PBDEs. Biodegradation of decabromodiphenyl ether (BDE 209) by a newly isolated bacterium from an e-waste recycling area Wu et al., 2018 Link
The biodegradation effect and mechanism of decabromodiphenyl ether (BDE-209) by crude enzyme extract from Pseudomonas aeruginosa were investigated. The results demonstrated that crude enzyme extract exhibited obviously higher degradation efficiency and shorter biodegradation time than Pseudomonas aeruginosa itself. Under the optimum conditions of pH 9.0, 35 °C and protein content of 2000 mg/L, 92.77% of the initial BDE-209 (20 mg/L) was degraded after 5 h. A BDE-209 biodegradation pathway was proposed on the basis of the biodegradation products identified by GC-MS analysis. The biodegradation mechanism showed that crude enzyme extract degraded BDE-209 into lower brominated PBDEs and OH-PBDEs through debromination and hydroxylation of the aromatic rings. View Full-Text Biodegradation of Decabromodiphenyl Ether (BDE-209) by Crude Enzyme Extract from Pseudomonas aeruginosa Liu et a., 2015 Link
In this study, an aerobic strain identified as Rhodococcus sp. was isolated from the sediment of a typical electronic waste disassemble site, Taizhou, China. This strain could use BDE-209 as the sole carbon and energy source and degrade 65.1 % of BDE-209 (initial concentration being 50 mg/L) within 144 h. To explore the BDE-209 degradation properties of this strain with the co-existed electronic donor, zerovalent iron/activated carbon (ZVI/AC) was introduced to build a microbial-chemical coupling system, which was found to promote the degradation of BDE-209 slightly (74.7 % in 144 h). Moreover, the debromination products in both of the batch experiments were determined with GC/MS, which showed that lower brominated PBDE congeners were produced almost in order of the number of bromine ions, ranged from nona- to di-BDEs. In addition, the possible debromination pathways of BDE-209 for each system were proposed respectively, which confirmed the microbial activity of BDE-209 debromination. Since some of the lower-brominated BDE congeners are much toxic than BDE-209, these microbial activities might bring potential hazards to the environment with BDE-209 contamination. It is the first time to investigate the transformation of BDE-209 with microbial-chemical coupling system, which is universal in the nature, thus suggesting that the ecological safety of environment exposed to PBDEs should be focused in the future. Aerobic debromination of BDE-209 by Rhodococcus sp. coupled with zerovalent iron/activated carbon Liu et a., 2015 Link
A metal resistant bacterial strain, Bacillus cereus JP12, could use decabromodiphenyl ether (BDE-209) as the sole carbon and energy source for growth in mineral salt medium. Under the conditions of pH 6.0, 30 °C, 150 rpm and an inoculum of OD600 = 0.6, more than 88% of the initial BDE-209 (1 mg/L) was degraded after 12 days. The addition of appropriate surfactants and additional carbon sources could enhance the biodegradation efficiency of BDE-209. The presence of Cu2+ (?8 mg/L) and Zn2+ (?15 mg/L) provided a slight stimulating effect on BDE-209 removal. However, BDE-209 biodegradation efficiency was decreased when adding higher levels of metals due to reduced substrate availability caused by excess metal adsorption into the cell surface. Biosorption of heavy metals by JP12 led to release of light metals such as K+ and Na+. A BDE-209 biodegradation pathway was proposed on the basis of metabolite identification. Biodegradation of decabromodiphenyl ether (BDE-209) by a metal resistant strain, Bacillus cereus JP12 Lu et al., 2013 Link
Due to widespread accumulation of polybrominated diphenyl ethers (PBDEs) in our surroundings, it is important to clarify their fate in the environment and the options of their elimination. The aim of this study was to monitor the biodegradation of the most frequent congeners (BDE 28, 47, 49, 66, 85, 99, 100, 153, 154, 183 and 209) under aerobic condition by indigenous microflora in 2 industrially contaminated sewage sludge samples. BDE 209 was detected as the predominating congener in concentrations 685 ng/g and 1403 ng/g dry weight in sewage sludge from WWTPs (waste water treatment plants) Hradec Kralove and Brno, respectively. The total amount of 10 lower PBDEs was 605 and 205 ng/g dry weight, respectively. The aerobic degradation was significantly enhanced by the addition of yeast extract and 4-bromobiphenyl. The total concentrations of all 11 PBDE congeners were lowered and their elimination was detected reaching 62–78% of their initial amounts after 11 months of cultivation. The degradation of most abundant congener BDE 209 followed the first-order kinetics with constant detected between 2.77 × 10?3 d?1 and 3.79 × 10?3 d?1 and the half-lives of BDE 209 degradation ranged between 6.0 and 8.2 months. This work clearly demonstrates that both lower brominated PBDEs as well as the major representative BDE 209 could be successfully removed from municipally contaminated sludge under aerobic conditions. Aerobic biodegradation of selected polybrominated diphenyl ethers (PBDEs) in wastewater sewage sludge Stiborova et al., 2015 Link
Decabromodiphenyl ether (BDE-209) is one of the most commonly used brominated flame retardants that have contaminated the environment worldwide. Microbial bioremediation has been considered as an effective technique to remove these sorts of persistent organic pollutants. Enterococcus casseliflavus, a gram-positive bacterium capable of aerobically transforming BDE-209, was isolated by our team from sediments in Guiyu, an e-waste dismantling area in Guangdong Province, China. To promote microbial bioremediation of BDE-209 and elucidate the mechanism behind its aerobic degradation, the effects of BDE-209 on the cell changes of E. casseliflavus were examined in this study. The experimental results demonstrated that the high cell surface hydrophobicity (CSH) of E. casseliflavus made the bacteria absorb hydrophobic BDE-209 more easily. E. casseliflavus responded to BDE-209 stress, resulting in an increase in cell membrane permeability and accumulation of BDE-209 inside the cell. The differential expression of intracellular protein was analyzed through two-dimensional gel electrophoresis (2-DE). More than 50 differentially expressed protein spots were reproducibly detected, including 25 up, and 25 down regulated after a 4 days exposure. Moreover, the apoptotic-like cell changes were observed during E. casseliflavus mediated degradation of BDE-209 by means of flow cytometry. Aerobic degradation of BDE-209 by Enterococcus casseliflavus: Isolation, identification and cell changes during degradation process Tang et al., 2016 Link
Decabromodiphenyl ether (BDE-209) is a brominated flame retardant and a priority contaminant. Currently, little information is available about its significance in the environment, specifically about its susceptibility to aerobic biotransformation at low temperature. In this work, five phylogenetically diverse BDE-209-degrading bacterial strains were isolated from river sediments of northern China. These strains were distributed among four different genera—Acinetobacter, Pseudomonas, Bacillus and Staphylococcus. All five isolates were capable of growing on BDE-209, among which two isolates show better growth. By detailed morphological, physiological, and biochemical characteristics and 16S rDNA sequence analysis, the two strains were identified and named as Staphylococcus haemolyticus LY1 and Bacillus pumilus LY2. The two bacteria can grow in mineral salt medium containing BDE-209 substrate across the temperatures ranging from 2.5 to 35 °C, with an optimum temperature of 25 °C which could be considered as psychrotrophs accordingly. The degradation experiment showed that more than 70.6 and 85.5 % of 0.5 mg/L BDE-209 were degraded and the highest mineralization efficiencies of 29.8 and 39.2 % were achieved for 0.5 mg/L BDE-209 by S. haemolyticus LY1 and B. pumilus LY2, respectively. To the best of our knowledge, this is the first demonstration for the biodegradation of BDE-209 by two psychrotrophic bacteria isolated from environment. Isolation and characterization of two novel psychrotrophic decabromodiphenyl ether-degrading bacteria from river sediments Wang et al., 2016 Link
Stenotrophomonas sp. strain WZN-1, isolated from an e-waste recycling area in Tianjin, China, is capable of degrading polybrominated diphenyl ethers (PBDEs). The complete genome of strain WZN-1 consists of 4,512,703 bp. This genome information will provide important information about the biodegradation pathways and mechanisms of PBDEs. Complete Genome Sequence of Stenotrophomonas sp. Strain WZN-1, Which Is Capable of Degrading Polybrominated Diphenyl Ethers Wu et al., 2017 Link
Aerobic biodegradation of decabromodiphenyl ether (PBDE-209) by Pseudomonas aeruginosa under the influence of co-metabolic substrates and heavy metal cadmium ion was studied, The results showed that certain amount of co-metabolic substrates, such as glucose, sucrose, lactose, starch, and beef extract, would promote the biodegradation of PBDE-209, among which glucose most favorably accelerated PBDE-209 degradation by about 36% within 5 d. The highest degradation efficiency was reached at the ratio of PBDE-209 and glucose 1:5 while excessive carbon source would actually hamper the degradation efficiency. Exploration of influences of cadmium ion on PBDE-209 biodegradation indicated that degradation efficiency was stimulated at low concentrations of Cd2+ (0.5–2 mg L?1) while inhibited at higher levels (5–10 mg L?1), inferring that the heavy metals of different concentrations possessed mixed reactions on PBDE-209 bioremoval. Bromine ion was produced during the biotransformation process and its concentration had a good negative correlation with the residues of PBDE-209. Two nonabromodiphenyl ethers (PBDE-208, PBDE-207), four octabromodiphenyl ethers (PBDE-203, PBDE-202, PBDE-197, PBDE-196) and one heptabromodiphenyl ethers (PBDE-183) were formed with the decomposition of PBDE-209, demonstrating that the main aerobic transformation mechanism of PBDE-209 was debromination. Aerobic biotransformation of decabromodiphenyl ether (PBDE-209) by Pseudomonas aeruginosa Shi et a., 2013 Link
Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and have consequently drawn much environmental concern. The objective of this study was to evaluate reductive debromination of decabromodiphenyl ether (BDE-209) by anaerobic microbes from river sediment under various conditions. The debromination rates for BDE-209 were enhanced by the addition of brij 30, brij 35, rhamnolipid, surfactin, vitamin B12, zero-valent iron, acetate, lactate, and pyruvate. Zero-valent iron yielded the highest BDE-209 debromination. For the various PBDE congeners, the high-to-low order of debromination rates in sediment was BDE-209 > BDE-99 > BDE-47 > BDE-28 > BDE-15. The intermediate products resulting from the reductive debromination of BDE-209 in sediment were nona-BDE (BDE-207), octa-BDEs (BDE-196, 197), hepta-BDEs (BDE-183, 184, 191), hexa-BDEs (BDE-138, 154), penta-BDEs (BDE-85, 99, 100, 119), tetra-BDEs (BDE-47, 49, 66, 71), tri-BDEs (BDE-17, 28), di-BDEs (BDE-7, 15), and mono-BDE (BDE-3). Our result shows BDE-209 can be debrominated successively to BDE-3 by anaerobic microbes from river sediment. This research offers feasible methods for removal of BDE-209 in river sediment for bioremediation. Reductive debromination of decabromodiphenyl ether by anaerobic microbes from river sediment Huang et al., 2014 Link
This work investigated degradation of decabromodiphenyl ether (BDE-209) by Phlebia lindtneri under the influence of glucose and heavy metals (Cd2+, Cu2+ or Pb2+). The results showed that adding glucose could markedly promote BDE-209 biodegradation. In the absence of heavy metals, 77.3% BDE-209 was degraded within 30 d when dealing with 20 mg L?1 BDE-209. BDE-209 degradation was stimulated at low concentrations of Cu and Pb, whereas inhibited at higher levels of metals. The culture pH tended to decrease with time. Adding lower concentrations of Cu (?5.0 mg L?1) enhanced laccase activity. No stimulatory effect was observed on laccase activity in the presence of Cd or Pb. Ecotoxicity in the culture significantly increased at the late stage of the experiment. Bromine ions were released and the debromination rate of BDE-209 was much lower than its degradation rate. The fungus could degrade BDE-209 through debromination, hydroxylation, and ring-opening reactions. Biodegradation of decabromodiphenyl ether (BDE-209) by white-rot fungus Phlebia lindtneri Xu and Wang. 2014 Link