Colin Murrell: fighting climate change with microbiology

Professor Colin Murrell is the first Director of the Earth and Life Sciences Alliance (ELSA), an initiative that aims to understand how earth and life systems respond to climate change.  ELSA draws together expertise from across Norwich Research Park combining, for example, the insights of molecular and cell biologists at the John Innes Centre with those of specialists in biodiversity, ecosystem services and international development at the University of East Anglia.

 An eminent microbiologist, Prof. Murrell has spent the last 28 years building up a strong research group at the University of Warwick. He was attracted to Norwich Research Park by the breadth and diversity of microbiologists – probably one of the highest concentrations of microbiologists in the UK.  

 What attracted you to Norwich Research Park?

It was the position of Director of the Earth and Life Sciences Alliance (ELSA), which was a particular draw for me.  I was excited by the idea of working with a multi-disciplinary team and the sheer breadth and depth of the expertise across Norwich Research Park with which  I could interact.

Having access to scientists who can see the big picture as well as the tiny detail is very important.  It is easy in science to become increasingly specialised and there is now much more emphasis on multidisciplinary science, which ELSA promotes. The attraction for me in Norwich is to see how microbiology fits into global strategies such as those for food security and response to climate change.

To give an example, we are currently coordinating internal workshops with subjects that range from the investigation of the detailed structure and regulation of enzymes involved in key biogeochemical cycles, right through to the modelling of whole ecosystems.

I arrived at the Norwich Research Park earlier this year, and in the past few years lots of scientists have also joined, attracted by the exciting areas of research emerging in Life and Environmental Sciences and it is these interactions and opportunities for collaboration that really  stimulates me.

How could microbiology be utilised in the fight against climate change?

Knowledge of the microbiology of elemental and nutrient cycles is core to our understanding of the environment. My research focuses on microbes that can feed on greenhouse gases such as methane and isoprene, which contribute to climate change.  Although microorganisms are responsible for driving the biogeochemical cycling of elements, there are very few methods for identifying which are the most important bacteria in the environment; this is why our work is so valuable.

Cutting the emissions of greenhouse gases and gases that harm the Earth’s atmosphere is essential. Understanding how microbes can feed on these chemicals before they are released into the atmosphere is necessary if we are to reduce the greenhouse effect and prevent the potentially catastrophic effects of steep rises in the Earth’s temperature over the next 50 years.

 What made the group look at this rather unusual microbiology application?

Simple single-cell organisms can live in all types of environmental conditions, for example hot springs, the oceans, industrial effluent and sewage outfalls.

Our particular area of expertise is in the study of methylotrophic bacteria that grow on what we call one carbon compounds, principally methane, methanol, methylated amines, dimethyl sulfide and methyl halides. Through our work and that of many colleagues it is becoming clear that these bacteria are more important in microbial food webs in both the terrestrial and marine environments than was first thought.

How do you identify which microbes will be useful in reducing greenhouse gases?

We have developed a method of identifying bacteria that can grow on specific compounds such as methane. Soil or seawater environments, for example, contain millions of different types of bacteria. We incubate environmental samples withmethane containing heavy ¹³C isotopes and the microbes that we are interested in are those that incorporate the ¹³C into their cell contents and molecules such as, DNA, protein and cell wall components. We extract DNA from the environmental sample. This contains all the genetic material from millions of different microbes. We then isolate the heavy, ¹³C -labelled DNA from our target microbes (that have grown on the ¹³C labelled methane) using centrifugation techniques. This DNA is the metabolic blueprint of the microbes that are growing on methane in the environment and so we can identify them without having to grow them in the lab. This technique is known as Stable Isotope Probing, which is a powerful method for finding out which microbes are active in the environment.

With recent technical advances, the cost of DNA sequencing is falling all the time.  With The Genome Analysis Centre located on the Norwich Research Park, we are ideally placed for applying both metagenomics and single cell genomics, to understand more clearly what microbes are carrying out key steps in biogeochemical cycles in the environment. By specifically labelling cells with isotopes and sorting them out, it is now possible to take only a few cells, in theory just one, and use genome amplification methods to rescue enough DNA to sequence the genome of the organism. This then gives valuable information on the genetic make-up and metabolism of the organism.

You have just received funding from the Gordon and Betty Moore Foundation?

The Gordon and Betty Moore Foundation Marine Microbiology Initiative focuses on understanding how microbes help live food webs in marine environments and our funding of around £750k is one of the few awards to be made to research groups outside of the USA.  The funding has allowed me to add four new researchers to my team.

Although we have worked in this area before, this is a very detailed study and will allow us to further develop our DNA Stable Isotope Probing Technique and combine it with metagenomics and single cell genomics.  Methane has an extremely important role in global warming.  By tagging organisms that are active in the metabolism of methane, it is possible to address the fundamental question in environmental science, ‘Who eats what, when and why?’.  When we have a better understanding of this, it will become possible to understand how life and earth systems are regulated and make predictions about how we may be able to combat the effects of global warming.

All natural systems have feedback mechanisms, if you can understand what these are then you can help mitigate the effects of global warming and climate change.

Our aim is to develop techniques using the methylotrophic bacteria, which I have been studying for nearly 30 years as a model system that can be applied to other microorganisms and different processes in the marine environment. This will help us to better understand how nutrients are cycled and what microorganisms are involved.

What are the future implications of the project?

The potential is the development of a microbiological toolkit that will enable us to improve our understanding of environmental processes and how they are regulated.  It will allow predictions of how marine ecosystems will respond to acidification and global warming, for example, and these will be based on robust scientific evidence.

In the future, it might also be possible to use these tools to enable rapid identification of microbes that can break down chemicals contaminating water supplies, soils and the marine environment, including oil spills. A good example of this would be the Deepwater Horizon oil spill in the Gulf of Mexico, where oil was quite quickly removed from the marine environment by microorganisms that used the various components in oil as a food source.

Stable isotope labelling can be used to identify which bacteria are active on these compounds and this type of approach would be beneficial in the fight to clean up pollutants in the environment. Ecosystems do self-regulate but there is point where it can break down.  For the Exxon Valdez oil spill disaster, it became apparent that the limiting factor was the availability of nitrogen and phosphorous, and when these were supplemented on the beaches covered in oil, the indigenous populations of microbes were able to break down the oil.

There are probably microbes out there in the environment which can break down pretty much any naturally occurring organic compound, however, what is more difficult are xenobiotics, man-made compounds, because the enzyme systems that microbes might need to degrade some of these compounds may not have had sufficient time to evolve.

Additionally, there are many microorganisms in the marine environment that have unknown properties, providing an untapped reservoir of new materials.  To be able to categorise them effectively opens up possibilities of using these microbes as the basis for new industries.

Also you have won funding from the NERC?

The £360k grant from NERC is to fund work on another atmospheric trace gas called isoprene which is a greenhouse gas about which we have much less information.  Again we will be looking at how microbes, with an enzyme system in the same family as the one needed to degrade methane, degrade this climate active gas.

You moved from an established career at Warwick, has it been worth it?

I did my doctorate at Warwick before moving to the University of Washington. I returned to Warwick in 1983, so had been  at Warwick for nearly 30 years when the prospect for this Directorship of ELSA  arose, which looked very attractive.  The move has been a good one, both for the opportunities it has created for the extension of primary research, but also for the development of new strands of multidisciplinary research, particularly with scientists who had been studying the same issues from a different perspective.

In February 2013 we will be holding a meeting to showcase the enormous breadth and depth of the work going on at the Norwich Research Park on elemental cycles including carbon, nitrogen and sulfur cycles and research into other trace elements such as iron.

Norwich Research Park is a very dynamic place to work and ELSA is proving a powerful mechanism for directing and moulding some very exciting areas of research.