The role of humic substances in the anaerobic reductive dechlorination of 2,4-dichlorophenoxyacetic acid by Comamonas koreensis strain CY01.
The role of the humic model compound, anthraquinone-2,6-disulfonate (AQDS), in the anaerobic reductive dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by the Fe(III)- and humic substances (HS)-reducing bacterium, Comamonas koreensis strain CY01 was investigated. The results taken as a whole indicated that (i) strain CY01 could couple glucose oxidation to 2,4-D reductive dechlorination; (ii) reductive dechlorination of 2,4-D by strain CY01 was greatly stimulated by the addition of AQDS; (iii) the transfer of electrons from biogenic AH(2)QDS to 2,4-D was an abiotic process which can take place in the absence of microorganisms; and (iv) AH(2)QDS was reoxidized during the chemical reaction, AQDS can serve again as electron acceptor for microorganisms, thus acting as electron shuttles. All the results suggested that 2,4-D reductive dechlorination by CY01 strain was a biochemical process that oxidizes the electron donors and transfers the electron to the acceptors through redox mediator, AQDS. We proposed the possible mechanism for the HS dependent reduction of 2,4-D. Our results suggested that microbial reduction of HS and subsequent chemical reduction of organic pollutants represent an important path of electron flow in anoxic natural environments. This work is a necessary preliminary step for better understanding the biodegradation of 2,4-D in subsurface soil.
Wang
Yibo
Y
College of Life Sciences, South China Normal University, Guangdong Key Lab of Biotechnology for Plant Development, Guangzhou, PR China. wangyb02@163.com
Wu
Chunyuan
C
Wang
Xiaojing
X
Zhou
Shungui
S
D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism*; D000693:Anaerobiosis; D000880:Anthraquinones / Q000378:metabolism; D001673:Biodegradation, Environmental; D020585:Comamonas / Q000378:metabolism*; D004579:Electron Transport; D006019:Glycolysis; D054879:Halogenation; D006812:Humic Substances
D000880:Anthraquinones; D006812:Humic Substances; C408124:anthraquinone-2,6-disulfonate; D015084:2,4-Dichlorophenoxyacetic Acid