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Developing microbial fuel cell-based biosensors for water quality monitoring

Primary Supervisor: Dr Shangfeng Du, School of Chemical Engineering

Secondary supervisor: Dr Yun Fan

PhD project title: Developing microbial fuel cell-based biosensors for water quality monitoring

University of Registration: University of Birmingham

Project outline:

Accurate and quick detection of toxic compounds and other contaminants and their quantification has posed a serious challenge in the field of environmental and clinical monitoring. Although classical analytical methods with sophisticated instrumentations yield good results in lab environment, their applicability and efficiency in real-time analysis at remote locations are doubtful. As a solution for this, microbial fuel cell (MFC)-based biosensors have gained considerable attention in recent years because of their advantages of on-site testing at remote locations without the need of external power supplies. However, MFC biosensors still encounter several bottlenecks in their practical application and scale-up. Among the main drawbacks, the limitation of electron transfer between microorganism and electrodes is considered as most challenging. It is a key aspect in the improvement of MFC performance. In order for MFC biosensors to be fully realised for wastewater quality monitoring, enhanced electron transfer is urgently required to fabricate biocatalyst electrodes with excellent stability, sensitivity, repeatability and selectivity. Based on an interdisciplinary collaboration established between the Centre for Fuel Cell and Hydrogen Research and the School of Biosciences at the University of Birmingham, this PhD project aims to develop highly sensitive and reliable MFC biosensors for toxicity detection in water quality monitoring. To achieve this, we will focus on the following three objectives:

Objective 1. To evaluate detection efficiency of potent candidate microbes, such as geobacter sulfurreducens, shewanella oneidensis, pseudomonas monteilii or their mixture, on toxicants (e.g. formaldehyde and heavy metals). This will be done via analysing microbial growth rate, generation time and high-throughput screening of potent biocatalysts.

Objective 2. To elucidate effects of microbial adhesion properties within MFC electrodes by monitoring biofilm formation on various substrates including graphite felt, stainless steel and Ni metal meshes, and novel 3D ordered substrates from 1D nanostructure arrays recently developed in principal supervisor's group. Distribution and adhesion of microbes on substrate surface within the electrodes will be analysed using scanning electron microscopy (SEM) and atomic force microscopy (AFM).

Objective 3. To evaluate and establish structure-sensing property relationships of the obtained biocatalyst electrodes in MFCs. The biocatalyst electrodes will be evaluated as both cathodes and anodes in single chamber MFCs, using different measurement techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses to define their sensitivity and reliability.

References:

  1. J. Chouler, Á. Cruz-Izquierdo, S. Rengaraj, J. L. Scott, M. D. Lorenzo. A screen-printed paper microbial fuel cell biosensor for detection of toxic compounds in water. Biosensors and Bioelectronics 2018, 102: 49-56, doi: 10.1016/j.bios.2017.11.018.
  2. P. Mardle, X. C. Ji, J. Wu, S. L. Guan, H. S. Dong, S. F. Du. Thin film electrodes from Pt nanorods supported on aligned N-CNTs for proton exchange membrane fuel cells. Applied Catalysis B: Environmental 2020, 260: 118031, doi: 10.1016/j.apcatb.2019.118031

BBSRC Strategic Research Priority: Renewable Resources and Clean Growth: Industrial Biotechnology . Understanding the Rules of Life: Microbiology

    Techniques that will be undertaken during the project:

    Characterisation:

    • Bacterial culture, growth analysis and biocatalyst screening
    • High Performance Liquid Chromatography (HPLC) to determine the toxicant in analytes.
    • Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses to understand the morphology and structure of microbes and their distribution on electrode substrates.
    • Atomic Force Microscopy (AFM) analysis to estimate the adhesion force between microbes and substrates.

    MFC sensor test:

    • Polarisation curve to evaluate the current density, voltage and power output of the MFC sensors to define their performance.
    • Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) to evaluate the metabolism kinetic rate of the electrodes.
    • Electrochemical impedance spectroscopy (EIS) analysis to define the conductivity, charger and mass transfer resistance of electrodes.
    • Amperometric response to evaluate the stability of sensors in toxicity detection.

    Contact: Dr Shangfeng Du, University of Birmingham