Newly Discovered Bacteria Can Generate Oxygen

by K. C. Jaehnig

CARBONDALE, Ill. -- Scientists at Southern Illinois University Carbondale have discovered a group of nearly 40 novel bacteria that humans could harness for use in such diverse tasks as environmental clean-up and the treatment of gangrenous war wounds.

These bacteria, which thrive in airless environments, have popped up in swine waste and in the Antarctic, in paper mill sludge and in soil scooped up near the SIUC library - - in fact, pretty much everywhere the researchers have looked for them. A diverse group of bugs, they all share a trait unique in the microbial world: Given the right kind of "food," they will crank out oxygen.

"An organism that in the absence of air can produce oxygen got us to thinking about possible applications - - and there are many," said microbial physiologist John D. Coates, who heads one of two SIUC research teams studying the bacteria.

"Among others, they could supply air tanks for deep-sea diving or long-distance space travel, and because oxygen inhibits the growth of the agent that causes gas gangrene, they could be used to develop the first-ever field treatment for deep-wound injuries" - - all possibilities for which Coates has applied for patents.

But what has caught the attention of the U.S. departments of defense and energy - - and more than $1 million combined funding in federal research support - - is the possibility that these bugs can help dispose of toxic waste.

One species already has proven itself a player in breaking down benzene, a cancer-causing compound used in making dyes and synthetic rubber. While this bacterium itself does not get rid of benzene, it can provide oxygen needed by other microbes that do.

"One of the big problems in contaminated environments is a lack of oxygen," Coates said. "Micro-organisms that can degrade organic compounds need oxygen; when they deplete it, biodegradation essentially comes to a standstill.

"We have shown that by coupling our organism with an organism that is able to degrade benezene, we can produce a 100-fold increase in the degradation rate: what once would take 700 days to remove, we can remove in seven."

They also have shown that this group of bugs can transform ferrous iron to ferric iron, which can be used to "trap" radioactive materials.

"Basically, it serves as an absorbent sponge that sucks the radioactive elements away and keeps them there," Coates said. "We have demonstrated that we can remove about 80 percent (of the radioactivity) within 24 hours." A new $72,286 grant from the U.S. Department of Energy will underwrite research aimed at determining which environments are best suited to this kind of clean-up and how to make the process more effective.

These organisms also can convert perchlorate, used in making rocket fuel, air bags, fireworks and matches, into harmless chloride, a component of table salt. Manufactured or used in almost every state, perchlorate has been a particular problem in the Southwest, turning up in water supplies of such states as California, Nevada and Utah. It recently has been associated with an increase in abnormal thyroid activity in Arizona newborns.

To locate these unique "clean-up" bacteria, Coates and company use several specialized probes - - molecules that seek out and attach to a specified gene so scientists can find it. Designed by SIUC molecular biologist Laurie A. Achenbach and her group, the probes look for a particular target that is only found in these bacteria.

"I can go anywhere in the world, sample the soil and tell within a day if the organisms are there," Achenbach said.

Achenbach also has been working on a "family tree" for these organisms, looking for connections that would show how each one relates to the others.

"We have found one specific group that has a lot of members (more than 50 percent of the organisms belong to this group), but the others are extremely diverse genetically and not related at all," she said.

Pinning down those relationships may eventually help the researchers fine-tune the bugs' clean-up capabilities. And that's important in a family that seems to be growing rapidly.

"In every study we do, we isolate new organisms all the time," Coates said.