Plant biologist Maren Friesen has been on a quest to find near-mythical bacteria that could fix their own nitrogen. Her search was based on results from Germany published in the 1990s that seemed to confirm their existence.
The end result, published in the current issue of Scientific Reports, proves the elusive bacteria, Streptomyces thermoautotrophicus, do in fact exist but don’t have any mythical qualities.
Most nitrogen-fixing bacteria use an enzyme that does not work when oxygen is present. The heat and toxic gas-loving strain that Friesen studied appeared to have exceptional properties, including harboring a special enzyme that was insensitive to oxygen.
Why go on such a quest?
Some unicorns are worth chasing, says Friesen.
While Friesen and an international team of scientists remained highly skeptical of the bacteria’s existence, the positive result in the literature had long tantalized researchers. However, there were no other papers from independent labs to confirm the original findings.
The myth began in Germany, where the bacteria were discovered. They thrived in the hot, toxic fumes over traditional charcoal fires where large quantities of wood were buried and burnt down.
Friesen’s collaborators traveled to Germany and gathered samples, while she went to Centralia, Pa., where underground coal fires have been burning for decades. She was somewhat surprised that she was able to find the bacteria, lending a bit of credence to the myth.
The tale grew even more when they produced a positive result in the laboratory, demonstrating that the bacteria did indeed fix their own nitrogen. This, however, turned out to be a tainted result.
Scientists from Harvard University, Imperial College (London), Aachen University (Germany) and Universidad Nacional de Rosario, Zavalla (Argentina) contributed to key aspects of the research. Rather than focus on one experiment, the team conducted many experiments around the world.
The National Science Foundation funded part of the research.