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Microbes Rule the World
This new story from Scientific American.com suggests that we may be able to harness microorganisms breaking down organic matter as a means of producing hydrogen. One of the main criticisms I've seen of using hydrogen fuel cells is that there are no readily useable sources of hydrogen around. Instead, we would have to produce hydrogen by (the only example I know off the top of my head) splitting water into hydrogen and oxygen. But that requires energy, so we would have to burn fossil fuels in order to produce the hydrogen that replaces our use of fossil fuels. It doesn't make sense to me either--maybe someone more knowledgable can explain. Anyway, this news article suggests that microorganisms--those master chemists--may be able to help us out.
Microbes don't get the attention and respect that they deserve--they really form the foundation of life on this planet. Evidence suggests that the very mitochondria and chloroplasts that provide us and plants with energy are derived from microorganisms. There are areas of research that seek to harness their abilites. Research in bioremediation, for example, seeks to harness microbes in the breaking down of man-made toxic chemicals. How practical these strategies are, I don't know--but they sound good.
While I'm at it, here are a few factoids I heard at a meeting: There are 50 million viruses per milliliter of coastal sea water. Viruses in the ocean constitute 27-270 megatons of carbon; whales constitute 4-12. Ninety-five percent of biomass in the ocean is microbial. Between 5 and 40% of marine microbes are lysed (broken open) by viruses each day. Viruses are therefore responsible for an enormous turnover of organic material in the ocean.
5 comments:
It seems there are lots of great ideas for producing hydrogen. An other good one Scientific American mentioned in their PBS show was using algae to produce fuel. Kind of of interesting.
The only problem is that none of these technologies nor hydrogen fuel cells themselves are quite ready for prime time, despite all the hype the last five years. The 2010 goal for hydrogen power seems unlikely to be met.
Any idea why there isn't more serious talk about ethanol?
The overall "cost" of ethanol is too high. Further there just isn't enough to produce the expected energies. It'd help a little and the midwest corn growers talk a lot about it, as do their congressmen. But from a scientific perspective it's really limited in utility for a variety of reasons.
The problem with ethanol is the low Energy Returned on Investment (EROI). If the net yield of energy created is not sufficiently high, then people will not expend the necessary energy to create it.
See this table for various EROIs.
I haven't been on campus for about 8 months now so I am a little out of the loop, but there have been some really great papers on this:
Scholz, F. & Schroder, U. (2003) Bacterial batteries. Nature Biotechnology 21: 1151-1152.
Chaudhuri, S. K. & Lovley, D. R. (2003) Electricity generation by direct oxidation of glucose in mediatorless microbial fuel cells. Nature Biotechnology 21: 1229-1232.
The thing about ethanol is that there is just not enough corn around to replace petrolium. If I remember right, converting all the corn in the US would lead to about a 30% dent in the petrolium.
For now, I am betting on aqueous reforming of carbohydrates for Hydrogen:
Davda, R. R. & Dumesic, J. A. (2004) Renewable hydrogen by aqueous-phase reforming of glucose. Chemical Communications 36-37.
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