Using bacteria to turn chocolate waste into electricity.

One of the criticisms of hydrogen fuel cells is that it isn’t really a truly “green” energy source because you still have to expend energy to get the hydrogen to make fuel cells with. In other words, while the use of hydrogen fuel cells is emission free, the process of getting the hydrogen is accomplished by electrolysis using electricity from coal fired power plants—in essence getting hydrogen from coal just shifts the pollution to the power plants. To be truly green we’d need a natural way of collecting hydrogen. Say perhaps via a multitalented bacterium with a sweet tooth?

The team fed Escherichia coli bacteria diluted caramel and nougat waste. The bacteria consumed the sugar and produced hydrogen, which they make with the enzyme hydrogenase, and organic acids. The researchers then used this hydrogen to power a fuel cell, which generated enough electricity to drive a small fan.

The process could provide a use for chocolate waste that would otherwise end up in a landfill. What’s more, the bacteria’s job doesn’t have to end once they have finished chomping on the sweet stuff. Mackaskie’s team next put the bugs to work on a production line that recovers precious metal from the catalytic converters of old cars.

The article is brief and doesn’t mention whether the amount of hydrogen produced by the bacteria is high enough to make large-scale hydrogen production via this method practical (let alone profitable), but it gives a new avenue to explore. Perhaps it could be possible to grow a bunch of sugar in a field and then toss it to some hungry bacteria and produce enough hydrogen to make for truly green fuel cells. Even if we still have to supplant this process with hydrogen produced by electrolysis anything that reduces the amount of “dirty” hydrogen we need to produce would be helpful.

9 thoughts on “Using bacteria to turn chocolate waste into electricity.

  1. Credit where it is due; George Bush dismisses the criticism that hydrogen comes from fossil fuel, with the rationale that once a demand for hydrogen is created (in the form of systems that distribute and use it) other methods of producing it will be developed. 

    In fact, this is already happening.  GE has a prototype hydrolysis machine that produces hydrogen at roughly gasoline-equivalent cost.  Should be on the market in about 2 years.  Plus, this bacteria, and who knows how many other projects are under way.

  2. One of the problems with the American Environmental Movement is what i call “Promoting The Polemical.”  Many, if not all, solutions present a host of new problems.  Some argue this is the very nature of the Universe and the second law of thermodynamics.  Regardless of the cause, this inherent attribute nature of problem-solving has, somehow, escaped the more radical American Environmentalists.

    One of the reasons we’re now planning (in a Very Big Way) to move away from a carbon to a hydrogen fueled economy is the related costs, in addition to the greenhouse-gas reductions.  It is important to remember that, yes, while the separation of hydrogen does emit greenhouse gases, it does so at markedly lower rates than …  than if we did nothing and merely espoused the problems of this solution—ignoring the benefits.

    It is important to remember that a hydrogen based economy, while presenting some new problems, does indeed solve some very, very large problems as well.  Weighing these cost-vs-benefits has, rarely, been a skill well used by the environmentalist radicals in America.

    Formulating public energy policy while relying upon some abstract, never-to-be-realized Principle of Environmental Perfectionism is naive, and ultimately risks our national security.  Let’s focus on real needs, and *workable* solutions, and leave the perfectionist-polemics for when we actually dig ourselves out of this soon-to-be-seen economic nightmare of Islamic-Oil dependance.

    rob@egoz.org

  3. the process of getting the hydrogen is accomplished by electrolysis using electricity from coal fired power plants

    Not necessarily.  One of the big problems in renewables is that you can not always produce them everywhere.  For instance, solar power is useless in places where the sun is not a reliable source- e.g much of North West Europe. (Joke about Manchester- if you can see the Pennine Hills, it is about to rain.  If you can’t see them, it’s already raining). Wind turbines are not always the answer for the slack, as windy days don’t always happen on cloudy ones.

    However, Hydrogen production becomes the new ‘oil’., as it can be transported. This would help the energy hungry nations of China, India and USA, all who have sunny areas. Put your Hydrogen production in Arizona and Nevada, Texas etc, and you have solar power to produce in house fuel. And ironically enough it would mean Saudi could still produce energy to export after the oil dries up.

    Of course the various rules about Thermodynamics, coupled with the fact that no system can be 100% efficient means the energy produced by your renewable plant would be more than that actually exported, but hey- it’s free.

    Non sunny areas need not miss out- hydrogen can be used to store wind and wave power.

  4. Sorry to double dip…I meant to say the only downer is the volatility of Hydrogen (see also, Hindenburg and R101.)

  5. The volatility of hydrogen is not especially a downer – we transport gasoline all the time.  But hydrogen embrittles most metals, which IS a problem.

  6. But before a couple of very high profile disasters we did it all the time- and they were 70 years ago.  They may not of thought of it as transporting hydrogen, but that is what the air ships did.

    My chemisrt isn’t great (I’m more of a amature physics geek), but can’t you pump it through clay pipes. 

    To get it across the world, you fill an airship up, empty it at the destination, then send the empty bag back.

    Also, why not just make the cells at the point of production?

  7. Of course the suggestion has been that hydrogen will be made in a non-green house gas producing manner by using nuclear reactors to generate the electricity required.  Ignoring the obvious nuclear waste problems nuclear power apparently has another problem if you believe some sources, namely that the world supply of uranium that’s economically mineable will only last something like 50 or 60 years at current rates of useage.

  8. Gee, wonder how much fissionable material we have carefully packed into warheads?  I’d be OK with using it to generate hydrogen.

    I think the storage problems of nuclear waste are more political than technical – there’s even an argument for well-guarded, centralized surface storage for later, more advanced use or storage.

    The hydrogen embrittlement problem is not insurmountable, but it complicates your choice of storage and transport alloys.  (Sulpher has the same effect on metals, BTW, as passengers on the Titantic may not have been aware)  There are various dopants and coatings that can be used for piping and components, and the hydrogen can be stored in various chemical binders.  We might even end up making a lot of components out of ceramics (an analogue of clay pipes?) or carbon-fibre reinforced plastics.  It’s just more complicated and expensive than handling hydrocarbons in metals as we have done since the first steam railroads.

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