Welcome to the blog of the course and textbook Facing up to global warming: What is going on and what you can do about it. This course is run by Professor Nick Gray of the Trinity Centre for the Environment at Trinity College Dublin.

Tuesday, April 9, 2013

Friendly microbes powering our lives: One bacterium at a time!

Bacteria: disease, illness and infection. These are the first words that come to mind when we think of our microorganism friends. Would you ever think of planetary space exploration, energy fuel cells or Greenhouse gas capture systems? These are knew avenues of cutting edge research that both industry and academic institutes are researching.  As a Microbiologist, these intrinsically diverse, complex and remarkable adaptable organisms fascinate me. From Volcanoes to ice, stratospheric clouds to oceanic depth, bacteria are found basically on all corners of the globe. We see them as pathogens, yet without them we could not survive. The smallest living organisms on Earth could become key to addressing some of the world’s biggest energy challenges.

Bacteria Power: Nature’s “badass” in world of energy production

Bacteria by nature are ferocious consumers of raw materials. But unlike us, they consume the waste we produce. The first law of thermodynamics states that energy is neither created or destroyed but is converted from one form to another. So, it’s obvious to use bacteria to produce our energy from waste? Sounds too good to be true I know, slightly science fiction. But in reality the process is already happening. Microbial fuel cells (MFC) are gathering recognition as viable means of producing electricity. Unlike conventional fuel cells that rely on hydrogen gas as a fuel source, the microbial fuel cell can handle a variety of water-based organic fuels such as sewage waste. By capturing the ions that bacterium leave behind when they eat, and then running the ions through a resistor to convert them to electricity, we can in essence generate our own power supply from simply biology. Researchers Biodesign Institute in Arizona, USA, are using these organisms a viable means to make electricity. "There is a lot of biomass out there that we look at simply as energy stored in the wrong place," said Bruce Rittmann, director of the center. "We can take this waste, keeping it in its normal liquid form, but allowing the bacteria to convert the energy value to our society's most useful form, electricity. They get food while we get electricity."

These simply yet novel ideas haven’t gone unnoticed by the “Big Industries”. Energy companies and Brewing Multinationals are at the forefront of MFC research. In May 2007, the University of Queensland, Australia, completed its prototype MFC, as a cooperative effort with Foster's Brewing. The prototype converts brewery wastewater into carbon dioxide, clean water, and electricity, which is estimated to produce 2 kilowatts of power. While it is a negligible amount of power, the production of clean water is of utmost importance to Australia, for which drought is a constant threat. Large-scale models are being developed with the hope of generating more energy capacity.

Bacteria powered personal devices: Science fiction or fact?
Great and all as this sounds, is there any chance that someday a bacteria will be used as an energy source in our iPhones? In 2012, a paper published in the prestigious  Nature Nanotechnology showed a MFC, manipulated with a bacteriophage (Virus that is harmless to humans but infects bacteria) produced up to 6 nanoamps of current and 400 millivolts of potential, which is about a quarter of a AAA battery's voltage. That's also enough to be used to operate a small liquid-crystal display. In their Nature paper, the scientists write that harmless virus-based piezoelectric materials potentially "offer a simple and environmentally friendly approach to piezoelectric energy generation."
Ultimate Sustainable Organisms
Microbial fuel cells are all natural. Energy generation and conservation are prevalent in all our lives. So are microbes, so why not combine the two and invest in a new means of sustainable energy production. Though, as a commercial entity it is years away from replacing conventional lithium batteries and fossil fuels. But as a model, they operate at natural temperatures using simple naturally occurring microorganisms to convert waste into energy. It's the ultimate sustainable energy system.

Karen Ward

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