Reductive dehalogenation of 3,5-dibromo-4-hydroxybenzoate by an aerobic strain of Delftia sp. EOB-17.
OBJECTIVE
To confirm the reductive dehalogenation ability of the aerobic strain of Delftia sp. EOB-17, finding more evidences to support the hypothesis that reductive dehalogenation may occur extensively in aerobic bacteria.


RESULTS
Delftia sp. EOB-17, isolated from terrestrial soil contaminated with halogenated aromatic compounds, completely degraded 0.2 mM DBHB in 28 h and released two equivalents of bromides under aerobic conditions in the presence of sodium succinate. LC-MS analysis revealed that DBHB was transformed to 4-hydroxybenzoate via 3-bromo-4-hydroxybenzoate by successive reductive dehalogenation. Highly conserved DBHB-degrading genes, including reductive dehalogenase gene (bhbA3) and the extra-cytoplasmic binding receptor gene (bhbB3), were also found in strain EOB-17 by genome sequencing. The optimal temperature and pH for DBHB reductive dehalogenation activity are 30 °C and 8, respectively, and 0.1 mM Cd(2+), Cu(2+), Hg(2+) and Zn(2+) strongly inhibited dehalogenation activity.


CONCLUSIONS
The aerobic strain of Delftia sp. EOB-17 was confirmed to reductively dehalogenate DBHB under aerobic conditions, providing another evidence to support the hypothesis that reductive dehalogenation occurs extensively in aerobic bacteria.
Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Kai
K
Chen
Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Shanshan
S
Jian
Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Linglong
L
Huang
Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Zhepu
Z
Ruan
Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Shunpeng
S
Li
Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China. jiang_jjd@njau.edu.cn.
Jiandong
J
Jiang
D000332:Aerobiosis; D001711:Biotransformation; D001970:Bromobenzoates / Q000378:metabolism*; D002853:Chromatography, Liquid; D042742:Delftia / Q000302:isolation & purification / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D019216:Metals, Heavy / Q000378:metabolism; D010226:Parabens / Q000378:metabolism; D012988:Soil Microbiology; D013696:Temperature
D001970:Bromobenzoates; D004791:Enzyme Inhibitors; D019216:Metals, Heavy; D010226:Parabens; C038193:4-hydroxybenzoic acid
3,5-Dibromo-4-hydroxybenzoate; Aerobic dehalogenation; Dehalogenation; Delftia sp.; Reductive dehalogenation