Lumichrome from the photolytic riboflavin acts as an electron shuttle in microbial photoelectrochemical systems

Xiang Li; Xiaochun Tian; Xinyu Yan; Nan Huo; Xuee Wu; Feng Zhao

doi:10.1016/j.bioelechem.2023.108439

Lumichrome from the photolytic riboflavin acts as an electron shuttle in microbial photoelectrochemical systems

Bioelectrochemistry. 2023 Aug:152:108439. doi: 10.1016/j.bioelechem.2023.108439. Epub 2023 Apr 7.

Authors

Xiang Li¹, Xiaochun Tian², Xinyu Yan³, Nan Huo¹, Xuee Wu⁴, Feng Zhao⁵

Affiliations

¹ Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, 422 Siming South Road, Xiamen 361005, Fujian, China; CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, Fujian, China.
² CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, Fujian, China.
³ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, Fujian, China; University of Chinese Academy of Sciences, 19 Yuquan Road, 100049, Beijing, China.
⁴ Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, 422 Siming South Road, Xiamen 361005, Fujian, China. Electronic address: xewu@xmu.edu.cn.
⁵ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, Fujian, China. Electronic address: fzhao@iue.ac.cn.

PMID: 37060705
DOI: 10.1016/j.bioelechem.2023.108439

Abstract

Riboflavin has been proposed to serve as an electron shuttle in photoelectrochemical systems. However, riboflavin was also observed for abiotic photolysis under illumination. Such conflicting reports raise the necessity for further investigation. In this study, riboflavin secreted by Rhodopseudomonas palustris was studied to clarify its stability and electron shuttle function under illumination. The data of high-performance liquid chromatography-mass spectrometry showed that the riboflavin was photolyzed to lumichrome in microbial photoelectrochemical systems. In addition, the anodic current increased by 75% after adding lumichrome compared with that of the control; it further demonstrated that lumichrome, not riboflavin, as an electron shuttle could facilitate microbial electron transfer. This study clarifies the mechanism of the interface process in microbial photoelectrochemical systems.

Keywords: Electron shuttle; Extracellular electron transfer; Lumichrome; Microbial photoelectrochemical systems; Riboflavin.

MeSH terms

Electron Transport
Electrons*
Flavins / metabolism
Photolysis
Riboflavin* / chemistry

Substances

7,8-dimethylalloxazine
Riboflavin
Flavins