George Kevin W, Häggblom Max M
Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, 76 Lipman Drive, New Brunswick, New Jersey 08901-8525, USA.
Environ Sci Technol. 2008 Aug 1;42(15):5555-61. doi: 10.1021/es800038q.
We demonstrated the O-methylation of tetrabromobisphenol-A (TBBPA) [4,4'-isopropylidenebis (2,6-dibromophenol)] to its mono- and dimethyl ether derivatives by microorganisms present in different sediments. A most probable number assay of a marsh sediment suggested that up to 10% of the total aerobic heterotrophs may be capable of O-methylation. Although TBBPA dimethyl ether is not produced in industry, it has been detected in terrestrial and aquatic sediments. Our study supports the hypothesis that TBBPA dimethyl ether is a product of microbial O-methylation. The O-methylation of TBBPA, as well as its analog, tetrachlorobisphenol-A (TCBPA), was also demonstrated in cultures of two chlorophenol-metabolizing bacteria, Mycobacterium fortuitum CG-2 and Mycobacterium chlorophenolicum PCP-1. These strains also mediated the O-methylation of 2,6-dibromophenol and 2,6-dichlorophenol, analogs of TBBPA and TCBPA, to their corresponding anisoles, but 2,6-fluorophenol was not transformed. Due to the addition of hydrophobic methyl groups, O-methylated derivatives are more lipophilic, increasing the probability of bioaccumulation in the food chain. Future research regarding the toxicological effects of the O-methylated derivatives of TBBPA is recommended and will further elucidate potential risks to environmental and human health.
我们证明了不同沉积物中存在的微生物可将四溴双酚A（TBBPA，4,4'-异亚丙基双（2,6-二溴苯酚））甲基化为其一甲基醚和二甲基醚衍生物。对沼泽沉积物进行的最大可能数分析表明，高达10%的总需氧异养菌可能具有O-甲基化能力。虽然工业上不生产TBBPA二甲基醚，但已在陆地和水生沉积物中检测到。我们的研究支持了TBBPA二甲基醚是微生物O-甲基化产物的假说。在两种氯酚代谢细菌——偶然分枝杆菌CG-2和氯酚分枝杆菌PCP-1的培养物中，也证明了TBBPA及其类似物四氯双酚A（TCBPA）的O-甲基化。这些菌株还介导了TBBPA和TCBPA类似物2,6-二溴苯酚和2,6-二氯苯酚向其相应苯甲醚的O-甲基化，但2,6-氟苯酚未被转化。由于添加了疏水甲基，O-甲基化衍生物更具亲脂性，增加了在食物链中生物累积的可能性。建议未来对TBBPA的O-甲基化衍生物的毒理学效应进行研究，这将进一步阐明对环境和人类健康的潜在风险。
