Dr Tim Overton

Supervisor Details

Contact Details

School of Chemical Engineering, University of Birmingham

Scientific Background

Research Interests

Dr Tim Overton is a biochemist and molecular microbiologist who is interested in applying molecular biology and single-cell techniques to understand and develop bioprocesses. He is active in microbial flow cytometry research and collaborates widely with bioprocess engineers, molecular microbiologists, cell biologists and environmental microbiologists to develop new methods of answering fundamental questions on a single-cell level.

His research also focuses on using bacteria to make useful products such as protein drugs and small molecules, and the bacterial responses to stress encountered in such processes. Current and recent research funding has come from the BBSRC, TSB and EU FP7.

Research Themes

Research is split into three main themes. Throughout each stream we are interested in applying microbial physiology to solve real-world problems and optimise processes. We work closely with industry to do this.

Fermentation for useful products
Bacterial biofilms
Microbes in processing streams

Scientific Inspiration

Isambard Kingdom Brunel – he was so ahead of his time, but was resolute in his vision. Many of the things he designed and built are still in regular operation.

Research Groups

Institute of Microbiology and Infection

Healthcare Technologies Institute (HTI)

School of Chemical Engineering

Supervision Style

In three words or phrases: Supportive, organised, guiding.

Provision of Training

I discuss training with each student as part of our regular meetings. If you prefer to find your own way to do things and discover methods from the literature, then that is fine – if you need more guidance, then that is also good. I would expect that you would move from the latter to the former as we progress through the project, so by the end you have independence in designing experiments and developing expertise. Hands-on training will be provided by members of my group, myself (for some methods), and collaborators.

Progression Monitoring and Management

We will have weekly meetings and track progression through the project. Each week we will agree on targets and look back at what has been achieved in terms of method and expertise development, data collection, and data analysis. We can meet on a more regular basis if needed, to solve problems if they occur. As we progress, we can switch to less regular meetings (once every two weeks) if required.

Communication

I think that communication is key to success in a PhD. I am happy to discuss anything with my students – not just project and scientific issues, but pastoral and personal matters as well. If I can’t help directly I can guide you in the right direction, including the wellbeing team. Outside of weekly meetings (face to face or via Skype / zoom etc.) I am setting up a group space in Microsoft Teams, and am contactable by email. Work-life balance is incredibly important and I would expect that students find their own balance. I don’t expect responses to emails or messages at all hours or weekends, and I usually switch off my email at weekends.

PhD Students can expect scheduled meetings with me:

In a group meeting

At least once per month

In year 1 of PhD study

At least once per week

In year 2 of PhD study

At least once per week (or less frequently if the student requests)

In year 3 of PhD study

At least once per week (or less frequently if the student requests)

These meetings will be a mixture of face to face, via video chat or telephone, and I am usually contactable for an instant response (if required) on every working day.

Working Patterns

The timing of work in my lab is completely flexible, and (other than attending pre-arranged meetings), I expect students to manage their own time.

Notice Period for Feedback

I need at least 2 weeks' notice to provide feedback on written work of up to 5000 words.

MIBTP Project Details

Current Projects (2025-26)

Primary supervisor for:

Efflux pumps for optimising bioproduction from renewable feedstocks

See the PhD Opportunities section to see if this project is currently open for applications via MIBTP.

Please Note: The main page lists projects via BBSRC Research Theme(s) quoted and then relevant Topic(s).

Efflux pumps for optimising bioproduction from renewable feedstocks

Secondary Supervisor(s): Professor Jessica Blair

University of Registration: University of Birmingham

BBSRC Research Themes: Renewable Resources and Clean Growth (Industrial Biotechnology)

Project Outline

Petrochemical feedstocks derived from crude oil are the basis of many of the materials and products that we use every day, from plastics to fuels. However, these feedstocks and processes are unsustainable and contribute to climate change. Therefore, there is currently a major shift globally to biological processes using renewable feedstocks. These feedstocks and processes increase sustainability and decrease carbon footprint, both critical for combating climate change and building a circular economy.

Bacteria have a major part to play in this drive for sustainability, and many chemicals and products previously made from crude oil-derived feedstocks using chemical processes are now made by bacteria from green feedstocks [Yang et al., 2021].

Bacteria constantly adapt to their environment and respond to stresses and toxic compounds that they encounter. A common mechanism that protects bacteria against a range of toxic molecules (such as organic solvents and antibiotics) are efflux pumps, molecular machines that pump such molecules out of the cell. It is known that efflux pumps make bacteria more tolerant to a range of solvents and other chemicals used in industrial processes [Tsukagoshi, 2000].

We have recently found that there is a fundamental link between the way in which bacteria generate energy (needed for growth, cellular functions, and product generation) and efflux pumps (required for removing harmful chemicals) [Whittle et al. 2024]. Energy is needed to drive efflux pumps, but we have discovered that the energy level within the cell is responsible for regulating fundamental behaviours, and that efflux pumps impact on these behaviours.

We think that this is very important in understanding how bacteria are able to survive in industrial processes and we can maximise product yields.

The main research questions are:

How is the energy state of the cell linked to efflux pumps?
How is this link regulated? What are the sensors and regulators involved in this process?
How does the energy state of the cell impact on organic solvent tolerance?
How can we use this link to improve bacterial processes that generate useful compounds?

We will use a combination of approaches, grounded in single-cell analysis of bacteria using flow cytometry and microscopy that we have previously developed [Whittle et al. 2019]. This will allow us to measure how individual bacteria respond to stresses, regulate their energy state, and control efflux pumps. We will also use a variety of molecular biology methods to genetically modify bacteria in order to better understand mechanisms of energy metabolism, efflux, organic solvent tolerance, and their regulation.

This interdisciplinary project will be supervised by Dr Tim Overton (School of Chemical Engineering), an expert on single-cell analysis of bacteria, bacterial physiology, and bioprocessing, and Professor Jessica Blair (Department of Microbes, Infection and Microbiomes), an expert on bacterial efflux pumps and antimicrobial resistance.

References

Tsukagoshi N, Aono R. (2000) Entry into and release of solvents by Escherichia coli in an organic-aqueous two-liquid-phase system and substrate specificity of the AcrAB-TolC solvent-extruding pump. J Bacteriol. 182(17):4803-10. doi: 10.1128/JB.182.17.4803-4810.2000.

Whittle EE, Legood SW, Alav I, Dulyayangkul P, Overton TW, Blair JMA. (2019) Flow Cytometric Analysis of Efflux by Dye Accumulation. Front Microbiol. doi: 10.3389/fmicb.2019.02319.

Whittle EE, Orababa O, Osgerby A, Siasat P, Element SJ, Blair JMA, Overton TW. (2024) Efflux pumps mediate changes to fundamental bacterial physiology via membrane potential. mBio0:e02370-24. doi: 10.1128/mbio.02370-24

Yang D, Prabowo CPS, Eun H, Park SY, Cho IJ, Jiao S, Lee SY. (2021) Escherichia coli as a platform microbial host for systems metabolic engineering. Essays Biochem. 65(2):225-246. doi: 10.1042/EBC20200172.

Co-supervisor on projects with Professor Jessica Blair, Professor Joan Geoghegan, Dr David Bassett and Professor Paula Mendes.

Previous Projects (2024-25)

Primary supervisor for:

Balancing the cost and benefit of efflux pumps in industrial applications

Co-supervisor on a project with Dr Sophie C Cox and Professor Joan Geoghegan.

Previous Projects (2023-24)

Primary supervisor for:

New tools for efficient recombinant protein production