The effect of electron competition on chromate reduction using methane as electron donor

Pan-Long Lv; Liang Zhong; Qiu-Yi Dong; Shi-Lei Yang; Wei-Wei Shen; Quan-Song Zhu; Chun-Yu Lai; An-Cheng Luo; Youneng Tang; He-Ping Zhao

doi:10.1007/s11356-017-0937-7

The effect of electron competition on chromate reduction using methane as electron donor

Environ Sci Pollut Res Int. 2018 Mar;25(7):6609-6618. doi: 10.1007/s11356-017-0937-7. Epub 2017 Dec 19.

Authors

Pan-Long Lv¹, Liang Zhong¹, Qiu-Yi Dong¹, Shi-Lei Yang¹, Wei-Wei Shen¹, Quan-Song Zhu¹, Chun-Yu Lai², An-Cheng Luo^{1

3

4}, Youneng Tang⁵, He-Ping Zhao^{6

7

8}

Affiliations

¹ College of Environmental and Resource Science, Zhejiang University, Hangzhou, China.
² College of Environmental and Resource Science, Zhejiang University, Hangzhou, China. laichunyu@zju.edu.cn.
³ Zhejiang Province Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China.
⁴ Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
⁵ Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310-6046, USA.
⁶ College of Environmental and Resource Science, Zhejiang University, Hangzhou, China. zhaohp@zju.edu.cn.
⁷ Zhejiang Province Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China. zhaohp@zju.edu.cn.
⁸ Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. zhaohp@zju.edu.cn.

PMID: 29255986
DOI: 10.1007/s11356-017-0937-7

Abstract

We studied the effect of electron competition on chromate (Cr(VI)) reduction in a methane (CH₄)-based membrane biofilm reactor (MBfR), since the reduction rate was usually limited by electron supply. A low surface loading of SO₄^2- promoted Cr(VI) reduction. The Cr(VI) removal percentage increased from 60 to 70% when the SO₄^2- loading increased from 0 to 4.7 mg SO₄^2-/m²-d. After the SO₄^2- loading decreased back to zero, the Cr(VI) removal further increased to 90%, suggesting that some sulfate-reducing bacteria (SRB) stayed in the reactor to reduce Cr(VI). However, a high surface loading of SO₄^2- (26.6 mg SO₄^2-/m²-d) significantly slowed down the Cr(VI) reduction to 40% removal, which was probably due to competition between Cr(VI) and SO₄^2- reduction. Similarly, when 0.5 mg/L of Se(VI) was introduced into the MBfR, Cr(VI) removal percentage slightly decreased to 60% and then increased to 80% when input Se(VI) was removed again. The microbial community strongly depended on the loadings of Cr(VI) and SO₄^2-. In the sulfate effect experiment, three genera were dominant. Based on the correlation between the abundances of the three genera and the loadings of Cr(VI) and SO₄^2-, we conclude that Methylocystis, a type II methanotroph, reduced both Cr(VI) and sulfate, Meiothermus only reduced Cr(VI), and Ferruginibacter only reduced SO₄^2-.

Keywords: Chromate reduction; Electron competition; Methane; Microorganism.

MeSH terms

Bacterial Physiological Phenomena
Biofilms
Bioreactors / microbiology
Chromates / chemistry*
Electrons*
Methane / chemistry*
Oxidation-Reduction

Substances

Chromates
Methane