Kenneth Nealson: Geobiology and Alternative Fuel

May 10, 2007

What's cleaner than coal, as renewable as solar energy and as ingenious as any of the cutting-edge alternative energy sources now being proposed for cars? The answer is microbe power, and if a USC team's efforts to harness its electrical punch succeed, it may one day find uses in applications both big and small.

Geobiologist Kenneth Nealson leads a USC College-based effort to develop bacteria-powered fuel cells that could act as remote, portable power supplies for a multitude of purposes. The project is funded by a $4.5 million Multidisciplinary University Research Initiative (MURI) grant.

Imagine a sewage treatment plant that uses its own waste to power itself, incidentally producing less sludge destined for landfills. Or perhaps an insect-like flying machine that can refuel itself by grazing off the land. In the ocean, hundreds or thousands of fish-like units might form an environmental sensor network that monitors pollution or blooms of poisonous algae.

The bacteria at the heart of the USC microbial fuel cell are Shewanella oneidensis MR-1, a microbe species discovered by Nealson. He and his collaborators have shown that this microbe, in addition to generating electricity, can "breathe" metal, clean up toxic residue in water and even keep brass, iron, copper and aluminum corrosion free.

Thanks to the combination of approaches used by Nelson's team, progress has been made in kicking up energy production from their first prototypes. Now the group has later-generation prototypes that work in the milliamp range %ue2%u20ac about enough electricity to power a digital watch or a refrigerator light bulb. For the applications they're interested in, they will need to increase power output another thousand-fold.

Help us understand a little bit more about what kind of work you do, and your progress thus far.

Our work focuses on the interactions between the geosphere (rocks, water, etc.) and life, at the level of electron transfer between the microbes and the "inert" Earth. This is what Geobiology is all about. We have bugs that can use natural materials as sources of electrons, much like you and I use batteries to run our flashlights. There are many such natural materials that can be used, giving the microbial world an immense versatility with regard to energy sources in comparison to the more "boring" higher organisms that are restricted to using organic carbon as an energy source.

But one can not make energy without having electron flow the electrons must flow from the source (electron donor) to and electron acceptor, and during this flow, energy is harvested for microbial growth. Higher organisms (animals, plants, etc.) use oxygen as the electron acceptor, and it is this reaction that provides all of our metabolic energy. Microbes can use a wide variety of different acceptors, including solids like iron and manganese oxides, and even toxic molecules like chromium and uranium. It is on these unusual, and potentially exploitable abilities that we focus our energy these days.

A subset of these studies involves understanding how microbes can be used to produce current in microbial fuel cells, using organic carbon as an energy source, and oxygen or some other electron acceptor as the electron acceptor. In fact, the microbes use the anode of the MFC as the electron acceptor much like they use solid state iron or manganese in nature.

What drives you to continue pursuing this area of study?

I believe that such activities are fundamental to life, and fundamental to the long-term survival of life and living systems on this (or any other) planet. Thus understanding these processes will be an essential part of understanding the system in which we live.

How might your work might impact people's lives, now and in the future?

The work with bioremediation of chromium and uranium contamination could have a major impact on water supplies, particularly in the LA basin area, where water in general is so dear.

The fuel cell approach could have a major impact because of the clean up of domestic and industrial waste on one hand, and the generation of water (clean and pure) on the other.

How did you come up with the idea?

Like all ideas, it has evolved over time I would say the past 2.5 years has seen the bulk of the maturation of these ideas.

Has anyone ever doubted that your idea could work?

I am sure it is so, but I know no details. I am used to this kind of response! It is quite common when one is doing research at the cutting edge new things tend to scare people!

What is the next step in the innovation process for you?

The next step is clear we need to use our understanding of these processes to design systems to make them useful for exploiting microbiology.

What is the one innovation you can't live without?

Well, I can't imagine any innovation I can't live without, including my own, but the one that seems most likely to help the "world" is that of the biofuel cells for processing human or industrial waste while generating energy, removing waste, and yielding clean water.

What would people be surprised to learn about you?

That I have never thought of myself as either a great scientist or a great innovator. I have just been having fun doing research and teaching for 35 years.

What do you wish you would have invented?

I marvel at inventions and always wonder where they come from. There is really not a one that I wish I had made, but many that I enjoy and try to learn from.

Any tips for aspiring innovators?

Enjoy science, enjoy research, enjoy teaching keep your eyes and ears open.

Galileo, Darwin, Einstein, Socrates or Newton? Other? Why?

Galileo by far. Imagine having that nice telescope and being able to see all these things others couldn't see. An entire new world opened and he got to be the first to figure it out. A bit like vanLeeuwenhoek and the microscope. To have such a tool and then take the time to invent a new discipline in one's lifetime must have been very inspiring indeed.

What is the most fun you've ever had?

The most fun was when we published the idea of microbial communication (so-called quorum sensing) that everyone was sure was wrong, and then spent the next 15 years watching others discover it -- over and over -- until it finally became an accepted idea. That is the fun of science.

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About Kenneth Nealson

Professor Nealson pioneered the field of modern geobiology an area of science that tackles the still largely unexplored domain where the processes and chemistry of life intersect with the planet's mineral and metal chemistry.

In his early work as a marine microbiologist, Nealson discovered quorum sensing, the phenomenon in which microbial communities create light. As one of the first to recognize the importance of microorganisms in catalyzing redox reactions in the environment, he has led the development of tools to study these organisms. Nealson's techniques, used to study microbial populations through genetic identification, are now considered standard in analyzing microbes found in biofilms.

On a much larger scale, Nealson has studied the cycling of such minerals as iron and manganese, revealing the key role of microorganisms in these biogeochemical processes. More recently, he has turned to figuring out how life can function in extreme environments, and he is directing efforts at NASA to search for life and evidence of ancient life in the solar system.