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Termite bacteria make hydrogen fuel

January 10, 2012

Jared Leadbetter at Cal Tech (the nice guy with the cat) studies tropical termite bacteria. Termites, you recall, chew up the wood of trees or houses, which their gut microbes digest for energy. But some termites do more interesting metabolism. Leadbetter was surprised to find that tropical termite guts contain spirochetes, monstrous spiral bacteria (like those that cause syphilis); but these termite spirochetes convert H2 and CO2 into acetate.

But where does the H2 come from? A huge amount of hydrogen gas comes from other bacteria in the termite gut community. These hydrogen-producing bacteria pull hydrogen atoms off of cellulose (from the wood the termites chew) and put the H atoms together as H2. (Why do they do this? The gut has no oxygen to accept the H electrons.) Termite mounds can grow to a mountain, big enough to see from a satellite. That’s an awful lot of hydrogen production. And the US Department of Energy has funded Leadbetter’s grant, “Massively Parallel, Microfluidics-Enabled Single Cell Analysis of Lignocellulose Conversion by Termite Hindgut Microbes.”

Could termite fuels be our next alternative source of fuel?

  1. Alex Tolley permalink
    January 10, 2012 9:44 pm

    I’d be skeptical. The efficiency of converting sunlight to cellulose in land plants is extremely low. Thus even if we did nothing but grow plants for fuel, they couldn’t supply our fuel needs. Algae as a cellulose source might be different, although direct production of biofuels makes more sense..

    But direct conversion of water to H2 even via solar PV and electrolysis is much more efficient, and artificial “leaves” promise to be even higher.

    Ideally, wouldn’t you want to convert cellulose to CH4 rather than H2? It extracts more energy from the cellulose and is easier to store and use.

    • January 10, 2012 10:44 pm

      The problem with CH4 (methane) is that it’s the worst greenhouse gas. And producing it always leaks huge amounts.

      There are other cleaner routes to H2, such as a bacterial fuel cell that makes electricity while splitting water. More on that later.

      • Alex Tolley permalink
        January 12, 2012 11:10 am

        The problem with CH4 (methane) is that it’s the worst greenhouse gas. And producing it always leaks huge amounts.

        While a concern, we do have a very large natural gas producing industry and are about to embark on an even bigger one with shale gas via “fracking”. AFAIK, the leakage rate of CH4 in the gas industry has been low and is not considered a major source of CH4 in the atmosphere compared to other sources. We already have crude methane producing digesters at the farm level, so I do not see why that would change if we industrialized this.

        • January 12, 2012 9:03 pm

          CH4 is a helpful short-term fuel. In the long term, on a large scale, CH4 leakage will be huge. And what gets burned ends up as CO2, still a greenhouse gas.

          By contrast, H2 burns clean–no carbon footprint whatsoever. Burning H2 with O2 just reverses photolysis.

          The main concern with H2 is how do you get it. Catabolism producing H2 (like that of termite bugs) produces approximately equal amounts of CO2. Other biomass conversion is even worse. So, photolysis looks more promising. If you engineer a purple bacterium to use photons to split water (and make electricity), then burn the hydrogen, that looks pretty good.

  2. SFreader permalink
    January 11, 2012 12:46 pm

    I think the more interesting aspect is the acetate connection rather than the energy production potential.

    From Wikipedia: “In nature, acetate is the most common building block for biosynthesis. For example, the fatty acids are produced by connecting C2 units derived from acetate.[1]”

    • January 12, 2012 8:46 am

      Yes, acetate is the two-carbon Lego block of metabolism. Hook them together to make membrane lipids; or modify to make amino acids.

  3. January 16, 2012 6:10 am

    My first thought was rocket termite mounds – with a flimsy wire frame for the termites to guide them into the right design and some genetic manipulation to make them builder stronger and more heatresistant outer shells we’ll get a very good competitor to Larry Nivens rocket trees.


  1. Termite bacteria make hydrogen fuel « Ultraphyte | Termites MAX

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