For the last 10 years, we have been working with bioelectrochemical systems, using electrogenic microorganisms able to transfer electrons to an external solid acceptor such as an electrode. If the electrode is connected via an external circuit to a cathode, an electric current is produced (of the order of mW/m2 of anode).
In this project, we will pursue the following lines of research connecting electrogenic bacteria and quantum effects:
1. Explore in detail the electron transport mechanisms between membrane cytrochromes and electrode along pili: is this a classical conductive transport, is it ion transport, or does it involve quantum tunnelling along a series of Fe-S clusters? For example, the quantum extension of the classical Drude theory of metal conductivity shows that regularly spaced potential wells (positive metal atom core) can achieve nearly 100% electron permeability through superposition of quantum wave packets. What permeability rates can the (regular?) potential wells associated with geometrical arrangement of FeS clusters in pili achieve?
2. So far, bio-electricity has been produced using metallic (or carbon) electrodes as the interface between the microbial electro-generation and the electric load. We want to examine here how using a semiconductor as the electrode influences the microbial metabolism and therefore electron transfer.
2a. Semiconductors are characterised by the energy-band gaps for electrons, implying that electrons in them can exist only a discrete potential / energy levels (as opposed to metals/carbon). Therefore, the electron donation process from microorganism is constrained by these potential bands. Therefore, microorganisms cannot change the energy-level at which it is donating electrons continuously, but only in discrete steps: How does this influence the composition and metabolism of a microbial species (or a microbial community) with respect to its electrogenicity?
3. Use semiconductor electrodes to create a varied and differentiated microbial community: Quantum effects allow to have a marked potential gradient along the surface of an electrode, and therefore electrogenic microbes with a preferred donation voltage would group better in the region where this potential exists along the gradient on the electrode surface. This potential gradient will allow for a completely new and efficient way to analyse the electrogenic behaviour in a multi-species community by differentiating the electric habitat along the gradient, while all the species still share a common biochemical habitat. This would allow for new communities to evolve that perhaps can metabolise incoming organic waste more efficiently: each species could donate electrons to the electrode at their preferred potential while still allowing exchange of partial oxidised organic compounds between them.
The project will commence on the 1st October 2019 and will finish on the 30th September 2022.
Second class degree or higher in a BSc or MSc or equivalent degree in biophysics, biological chemistry, bioelectronics or bioengineering would be desirable. Experience in computer modelling of biological reactions and / or modelling of charge transfer and transport in biological / organic / inorganic systems. Applicants who have an A Level or equivalent in Mathematics, Physics or Engineering will be at an advantage. A willingness to work across the disciplines is essential.
If English is not your first language, you will be required to have an IELTS Academic of 6.5 or above (or equivalent), with no sub-test score below 6.
How to apply:
Applications can be made through our Biosciences and Medicine Course page https://www.surrey.ac.uk/postgraduate/biosciences-and-medicine-phd
Please state the project title and supervisor clearly on all applications.