Conduction Band of Hematite Can Mediate Cytochrome Reduction by Fe(II) under Dark and Anoxic Conditions

Liu, Tongxu1,2; Wang, Ying1; Liu, Chongxuan3; Li, Xiaomin4,5; Cheng, Kuan1; Wu, Yundang1; Fang, Liping1; Li, Fangbai1; Liu, Chengshuai1

2020-04-21

10.1021/acs.est.9b06141

ENVIRONMENTAL SCIENCE & TECHNOLOGY   影响因子和分区

0013-936X

1520-5851

While it was recently reported that the conduction band of iron minerals can mediate electron transfer between Fe(II) and different Fe(III) lattice sites during Fe(II)-catalyzed mineral transformation, it is unclear whether such a conduction band mediation pathway occurs in the microbial Fe(II) oxidation system under dark and anoxic subsurface conditions. Here, using cytochrome c (c-Cyts) as a model protein of microbial Fe(II) oxidation, the in vitro kinetics and thermodynamics of c-Cyts reduction by Fe(II) were studied. The results showed that the rates of c-Cyts reduction were greatly enhanced in the presence of the semiconducting mineral hematite (Hem, alpha-Fe2O3). The electrochemical experiments separating Fe(II) and c-Cyts demonstrated that electrons from Fe(II) to the electrode or from the electrode to c-Cyts could directly penetrate hematite, resulting in enhanced current. Independent photochemical and photoluminescence experiments indicated that c-Cyts could be directly reduced by the conduction band electrons of hematite which were generated under light illumination. In c-Cyts+Fe(II)+Hem, the redox potential of Fe(II)-Hem was shifted from -0.15 to -0.18 V and that of c-Cyts+Hem changed slightly from -0.05 to -0.04 V. For the bulk hematite, Mott-Schottky plots illustrated that the flat band was shifted negatively and positively in the presence of Fe(II) and oxidized c-Cyts, respectively, and the surface electron/charge density was higher in the presence of Fe(II)/c-Cyts. As a consequence, the redox gradients from adsorbed Fe(II) to adsorbed c-Cyts allow electron transfer across the conduction band of hematite and facilitate c-Cyts reduction. This mechanistic study on conduction band-mediating electron transfer could help interpret the role of semiconducting minerals in the microbial Fe(II) oxidation process under dark anoxic conditions.

SCI ; EI

英语

NI论文

其他

Guangdong Academy of Science Project of Science and Technology Development[2017GDASCX-0106] ; Guangdong Academy of Science Project of Science and Technology Development[2018GDASCX0501]

Engineering ; Environmental Sciences & Ecology

Engineering, Environmental ; Environmental Sciences

WOS:000527738300013

AMER CHEMICAL SOC

ENVIRONMENT/ECOLOGY

Web of Science

1.Guangdong Inst Ecoenvironm Sci & Technol, Guangdong Key Lab Agr Environm Pollut Integrated, Guangzhou 510650, Peoples R China
2.Natl Reg Joint Engn Res Ctr Soil Pollut Control &, Guangzhou 510650, Peoples R China
3.Southern Univ Sci & Technol, Sch Environm Sci & Engn, State Environm Protect Key Lab Integrated Surface, Shenzhen 518055, Peoples R China
4.South China Normal Univ, SCNU Environm Res Inst, Guangdong Prov Key Lab Chem Pollut & Environm Saf, Guangzhou 510006, Peoples R China
5.South China Normal Univ, MOE Key Lab Environm Theoret Chem, Guangzhou 510006, Peoples R China

Liu, Tongxu,Wang, Ying,Liu, Chongxuan,et al. Conduction Band of Hematite Can Mediate Cytochrome Reduction by Fe(II) under Dark and Anoxic Conditions[J]. ENVIRONMENTAL SCIENCE & TECHNOLOGY,2020,54(8):4810-4819.

Liu, Tongxu.,Wang, Ying.,Liu, Chongxuan.,Li, Xiaomin.,Cheng, Kuan.,...&Liu, Chengshuai.(2020).Conduction Band of Hematite Can Mediate Cytochrome Reduction by Fe(II) under Dark and Anoxic Conditions.ENVIRONMENTAL SCIENCE & TECHNOLOGY,54(8),4810-4819.

Liu, Tongxu,et al."Conduction Band of Hematite Can Mediate Cytochrome Reduction by Fe(II) under Dark and Anoxic Conditions".ENVIRONMENTAL SCIENCE & TECHNOLOGY 54.8(2020):4810-4819.