Researchers Sequence Genome of Hydrogen-Producing Bacterium
02 December 2005
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| Genomic organization of C. hydrogenoformans |
Scientists at The Institute for Genomic Research (TIGR) have sequenced the genome of Carboxydothermus hydrogenoformans, a fast-growing thermophilic microbe that lives on carbon monoxide and produces hydrogen gas and CO2 as waste.
The analysis of the genome is providing insights into the metabolism of this organism that should aid those trying to develop this and similar species into systems to produce hydrogen gas biologically from water.
C. hydrogenoformans is one of the fastest-growing microbes that can convert water and carbon monoxide to hydrogen. So if you’re interested in making clean fuels, this microbe makes an excellent starting point.
—Jonathan Eisen, senior author of the TIGR study, published in PLoS Genetics
C. hydrogenoformans serves as a model for studies of hydrogenogens—diverse bacteria and archaea that grow anaerobically utilizing carbon monoxide (CO) as their sole carbon source and water as an electron acceptor, producing CO2 and H2 as waste products. Organisms that make use of CO do so through enzymes called carbon monoxide dehydrogenases (CODH).
Eisen and his collaborators discovered that C. hydrogenoformans encodes five different forms of carbon monoxide dehydrogenase (CODH). Most species have no CODH and even species that utilize CO usually have only one or two.
Each form of the enzyme appears to have different cellular roles—i.e., allows the organism to use carbon monoxide in a different way.
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| Locations of genes predicted to encode five CODH complexes. Possible cellular roles for four of the five CODH complexes are indicated. |
Building off this work, TIGR scientists are leveraging the information from the genome of this organism to study the ecology of microbes living in diverse hot springs, such as those in Yellowstone National Park. The C. hydrogenoformans in the study was isolated from a Russian volcanic hot-spring.
Support for the TIGR project came from the US Department of Energy, Office of Biological Energy Research.
Resources:
Life in Hot Carbon Monoxide: The Complete Genome Sequence of Carboxydothermus hydrogenoformans Z-2901; Martin Wu, Qinghu Ren, A. Scott Durkin, Sean C. Daugherty, Lauren M. Brinkac, Robert J. Dodson, Ramana Madupu, Steven A. Sullivan, James F. Kolonay, William C. Nelson, Luke J. Tallon, Kristine M. Jones, Luke E. Ulrich, Juan M. Gonzalez, Igor B. Zhulin, Frank T. Robb, Jonathan A. Eisen; PLoS Genetics Vol. 1, No. 5, e65; DOI:10.1371/journal.pgen.0010065
Produces CO2? Hmmm. Back to the drawing board.
Posted by: tom | 02 December 2005 at 10:58 AM
1) You have to catalize incomplete fossil or even renewable bio fuel combustions somehow.
2) Microbes are cheaper for catalysts than precious metals.
3) If you can seperate them and sequester the CO2, you've got a home run.
Posted by: LochDhu | 02 December 2005 at 12:34 PM
A totally unneccesary technological path. Methanogenic microbes are easier to use and live off of animal and plant wastes making them GHG neutral.
Posted by: tom deplume | 02 December 2005 at 02:52 PM
How about feed them with syngas and produce H2 and CO2? Wait, that sound really like methane reforming process.
This is a starting point, and i am interested to know how fast is "fast-growing", i am imagining a fuel cell car with a tank of bacteria and a CO gas tank.
Posted by: rexis | 02 December 2005 at 05:17 PM
tom - it's too early to send this back to the drawing board. If this produces only one quarter of the CO2 per energy unit compared to fossil fuels, it would still be a huge win.
Plus, they take CO and output CO2. if you take the CO2 to produce the CO, you're left with extra O2 and something that could theoretically be made carbon-neutral (assuming all the CO2 is captured and perfectly transformed into CO with no loss of carbon).
Posted by: Daniel Haran | 03 December 2005 at 12:07 PM
C. hydrogenoformans grows with a doubling time of 2 hours, so it grows much faster than methanogens. However, it grows optimally at around 70 C and under strict anaerobic conditions, so putting a tank of it in a car probably won't work.
The DOE did research into a different bug that also had a CO to H2 pathway, but recently gave it up becasue the technological applications were limited. However, C. hydrogenoformans has extraordinary rates of H2 evolution, so interest may be revived.
Posted by: Steve | 04 December 2005 at 03:47 PM
CO2 is not a problem, it can be easily be captured and sequestered. The 70C temperature requirement could be met using the waste heat from power plants, coal or nuclear. Where will we get a large, cheap supply of CO to feed the little buggers? I'm sure it's a waste product somewhere and being dumped into the atmosphere.
As for methanogenic microbes being easier to use, well let's pursue that avenue too! No reason to exclude other lines of research; competition is good.
Posted by: Timetrvlr | 06 December 2005 at 12:34 PM