Inside a small cabinet the size of a dorm refrigerator in one of Himadri B. Pakrasi's labs, a blue-green soup percolates in thick glass bottles under the cool light of red, blue and green LEDS.
This isn't just any soup, however. It is a soup of champions.
The soup is colored by a strain of blue-green bacteria that bubble off roughly 10 times the hydrogen gas produced by their nearest competitorsin part because of their unique genetic endowment but also in part because of tricks the scientists have played on their metabolism.
Hydrogen gas can be produced by microbes that have enzymes called hydrogenases that take two hydrogen ions and bind them together. Although the soup microbes have hydrogenases, most of the hydrogen they evolve is a byproduct instead of an exceptionally efficient nitrogenase, an enzyme that converts the nitrogen in air to a nitrogen-containing molecule the microbes can use.
The microbe's gas-producing feat is described in December 14,2010 issue of the online journal Nature Communications.
Biohydrogen, like that bubbling up from the microbial soup, is one of the most appealing renewable energy fuels. Produced by splitting water with energy from the sun, it releases mostly water when it burns. It's hard to get any cleaner than that.
The strain growing in the Roux bottles in the cabinet, called Cyanothece 51142 was originally found in the Gulf of Mexico by Louis A. Sherman of Purdue University, one of the article's authors. Its genes were sequenced in 2008 at the Genome Sequencing Center at the School of Medicine.
Cyanothece 51142 may be new to science, but cyanobacteria, the group of organisms to which it belongs, have existed for at least 2.5 billion years, says Pakrasi, PhD, the George William and Irene Koechig Freiberg professor of biology in Arts & Sciences, and professor of energy in the School of Engineering. These ancient organisms have had to survive a
|Contact: Diana Lutz|
Washington University in St. Louis