Biodegradation of Polybrominated diphenyl ethers in river sediment

• Main Authors: Huang, Huang-Wen, 黃皇文
• Other Authors: Chang, Bea-Ven
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/29893833473487647765

博士 === 東吳大學 === 微生物學系 === 102 === Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and have consequently drawn much environmental concern. The objective of this study was to evaluate biodegradation of PBDEs and microbial community change in river sediment. The anaerobic debromination rates for decabromodiphenyl ether (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. 2,4,4`- tribromodiphenyl ether (BDE-28) have the same result. 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). The aerobic degradation of 4,4`- dibromodiphenyl ether (BDE-15) was enhanced by the addition of surfactin or rhamnolipid, and was inhibited by the addition of brij 30 or brij 35. The addition of BDE-degrading bacteria could also enhance the efficiency of BDE-15 degradation in sediment. Pseudomonas sp. and Bacillus sp. were found to be the dominant bacteria in the process of BDE-15 degradation in the sediment. The optimal conditions were stimulated by the addition of surfactin into the sediment. The degradation of BDE-15 was enhanced by a second and third addition of BDE-15 into the batch cultures. The BDE-15 degradation observed in the bioreactor experiment. This result indicated that addition of BDE-15 a second or third time might increase the BDE-degrading activity of microorganisms. The pyrosequencing technology for profiling microbial communities showed that degradation of PBDEs to appear related bacteria. The major population is Methanobacterium spp. and Clostridium spp. in BDE-209 and BDE-28 anaerobic degradation experiments. For the various PBDE congeners, BDE-15, BDE-28, BDE-47, BDE-99 and BDE-100 the major population is Clostridium spp., Oscillibacter spp., Thiobacillus spp., Pseudomonas spp., Blastocatella spp. and Paenibacillus spp. in aerobic degradation experiments. Our result shows BDE-209 can be debrominated successively to BDE-3 by anaerobic microbes from river sediment. These findings could provide useful information for bioremediation of PBDEs contaminated sites. This research offers feasible methods for removal of BDE-209 in river sediment for bioremediation. Key word: Polybrominated diphenyl ethers, sediment, anaerobic degradation, aerobic degradation, pyrosequencing.