Microbial respiration is a central driving force for various biogeochemical cycles and bioremediation processes. To stimulate the intrinsic bioremediation process in contaminated subsurface environments, adding electron acceptors such as oxygen, sulfate, nitrate or ferric iron have been proved to be an efficient strategy (termed respiration-regulating remediation, RRR). Anodes in bioelectrochemical systems (BES) particularly microbial fuel cells (MFC), is a novel artificial electron acceptor to stimulate the microbial degradation of various organic contaminants simultaneously with electricity generation. Given the different physicochemical properties of the electron acceptors used in RRR, different contaminant degradation profile can be assumed in RRR. However, most of reported studies focused on only certain contaminants by one RRR method. The wide degradation pattern of organic chemicals in RRR has not been reported independently or comparatively, even though it could provide crucial information for choosing the suitable remediation method in a given contaminated environments.
Generally, the electron acceptors in microbial respirations can be divided into two forms: soluble and insoluble. This study compared the global degradation profiles of solid anode in microbial fuel cells and soluble nitrate in contaminated sediments. 68 putative organic compounds in the sediments before and after treatment were analyzed. The results showed a clear trend that microbial fuel cells prefers to degrade high polar chemicals while the nitrate addition prefers to degrade low polar chemicals. We believe this study provides crucial information for proper applications of the two RRR methods and even other related microbial environmental technologies.
Xia C1, Xu M2, Liu J3, Guo J4, Yang Y5.Show Affiliations
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China; Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.
- University of Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China; State Key Laboratory of Applied Microbiology, Southern China (The Ministry-Province Joint Development), Guangzhou, China.
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China; State Key Laboratory of Applied Microbiology, Southern China (The Ministry-Province Joint Development), Guangzhou, China. Electronic address: [email protected]
By operating a SMFC in heavily contaminated sediment and analyzing its global organic chemical degradation profile, this study showed a brief trend that SMFC prefers to stimulate the degradation of organic chemicals with higher polarity. As a comparison, adding nitrate as a microbial respiration-based sediment remediation strategy preferred lower polarity chemicals. Both SMFC and nitrate reactors showed high degradation capacity in benzene homologs. These results provide crucial information for the selective and proper application of SMFC in bioremediation.
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