Microbial Degradation Of Tetrabromodiphenyl Ethers And Methods For Enhancement

2,2',4,4'-tetrabromodiphenyl ether?BDE-47?with low bioavailability and high bioaccumulation is one of polybromodiphenyl ethers?PBDEs?,which is widely detected from soils,sediments,airs,waters and even biota.Owing to the biotoxicity of BDE-47 included thyrotoxic and neurovirulence,the contamination and removal of BDE-47 in environment are increasing paid attention on.It is a safe,low-cost and efficient method for microbial degradation to remove the pollution of BDE-47,while the research on the biodegradation of BDE-47 is little.This paper isolated two of BDE-47 degrading strains?Bacillus cereus and Alcaligenes feacalis?with morphology,physiological biochemistry and molecular biology from contaminated soils at Guiyu Town,Guangdong Province.Under aerobic conditions,the biodegradation rate of BDE-47 was 61.60%by Bacillus cereus within 14 d.The process fitted with first order kinetics reaction,and the rate constant k was 0.0728 d^-1 and the half-life t_1/2/2 was 8.64 d.The biodegradation rate of BDE-47 was stimulated with the addition of carbon sources and inducers,while inhibited with hydroquinone and surfactants.Under anaerobic conditions,the biodegradation rate of BDE-47 was 51.61%by Alcaligenes feacalis within 14 d.The process fitted with first order kinetics reaction,and the rate constant k was 0.0514 d^-1 and the half-life t_1/2/2 was 13.46 d.The biodegradation rate of BDE-47was stimulated with the addition of carbon sources,electron acceptors and inducers,while inhibited with NO₃^-and surfactants.Furthermore,the paper deduced the pathways of BDE-47 degradation by strains under aerobic and anaerobic conditions.