Promotion of iron oxide reduction and extracellular electron transfer in Shewanella oneidensis by DMSO.
The dissimilatory metal reducing bacterium Shewanella oneidensis MR-1, known for its capacity of reducing iron and manganese oxides, has great environmental impacts. The iron oxides reducing process is affected by the coexistence of alternative electron acceptors in the environment, while investigation into it is limited so far. In this work, the impact of dimethyl sulphoxide (DMSO), a ubiquitous chemical in marine environment, on the reduction of hydrous ferric oxide (HFO) by S. oneidensis MR-1 was investigated. Results show that DMSO promoted HFO reduction by both wild type and ΔdmsE, but had no effect on the HFO reduction by ΔdmsB, indicating that such a promotion was dependent on the DMSO respiration. With the DMSO dosing, the levels of extracellular flavins and omcA expression were significantly increased in WT and further increased in ΔdmsE. Bioelectrochemical analysis show that DMSO also promoted the extracellular electron transfer of WT and ΔdmsE. These results demonstrate that DMSO could stimulate the HFO reduction through metabolic and genetic regulation in S. oneidensis MR-1, rather than compete for electrons with HFO. This may provide a potential respiratory pathway to enhance the microbial electron flows for environmental and engineering applications.
Department of Chemistry, University of Science & Technology of China, Hefei, China.
Yuan-Yuan
YY
Cheng
Bing-Bing
BB
Li
Dao-Bo
DB
Li
Jie-Jie
JJ
Chen
Wen-Wei
WW
Li
Zhong-Hua
ZH
Tong
Chao
C
Wu
Han-Qing
HQ
Yu
D001426:Bacterial Proteins / Q000096:biosynthesis; D003451:Cryoprotective Agents / Q000494:pharmacology*; D003574:Cytochrome c Group / Q000096:biosynthesis; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005290:Ferric Compounds / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D010084:Oxidation-Reduction / Q000187:drug effects; D020592:Shewanella / Q000378:metabolism*
D001426:Bacterial Proteins; D003451:Cryoprotective Agents; D003574:Cytochrome c Group; D005290:Ferric Compounds; C000499:ferric oxide; D004121:Dimethyl Sulfoxide