Microbial electrochemical sensor for water biotoxicity monitoring

Na Chu^a, Qinjun Liang^a, Wen Hao^b, Yong Jiang^a, Peng Liang^b, Raymond Jianxiong Zeng^a

Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.

Abstract

The development of low cost, convenient, and efficient biosensors is critical for water biotoxicity monitoring. Microbial electrochemical sensors employ electrode-biofilm as the sensing element, and detect biotoxicity by tracking the electron transfer between electroactive microorganisms and electrodes under toxic stress. Use of such biosensors in the aquatic environment can provide an early warning for the presence of various toxicants. In this paper, cutting-edge studies on strategies to create high performance microbial electrochemical biosensors are reviewed, which have mainly focused on different sensing elements. Bioanode sensing element-based microbial electrochemical sensors have been successfully applied in the laboratory to detect various toxicants, and to diagnose typical anaerobic wastewater treatment processes. The abiotic cathode sensing element is also included, which is mainly based on the electrochemical reduction of target analytes or its inhibition of the oxygen reduction reaction (ORR). The biocathode sensing element successfully solves the problems of low sensitivity and high false-negative rate, and recent advances and future perspectives in this field are highlighted. The limitations and potential solutions associated with the practical application of microbial electrochemical sensors for water biotoxicity monitoring are discussed.

Keywords: Biosensors, Extracellular electron transfer, Microbial electrochemistry, Biocathode, Electroactive microorganism.