New strains of bacteria found living in the 28,000 year-old Rancho La Brea tar pits in Los Angeles could prove useful in our modern world.
Discovered in the oil-drenched soil at one of the world’s greatest burial sites of prehistoric ice age animals and plants, the bacteria and enzymes within them are showing interesting properties that could be used in the medical and biofuel industries, not to mention cleaning up oil and other hydrocarbon spills.
Two scientists at the University of California-Riverside (UCR) noticed bubbles of methane rising out of the pits of oily asphalt at the site in downtown Los Angeles, and determined the source of the gas to be bacteria living comfortably on and in the gooey mess. The odd discovery found at Pit 91 initiated a study by Jong-Shik Kim, a postdoctoral researcher in the Department of Environmental Sciences.
“We were surprised to find these bacteria because asphalt is an extreme and hostile environment for life to survive,” Kim said. “It’s clear, however, that these living organisms can survive in heavy oil mixtures containing many highly toxic chemicals. Moreover, these bacteria survive with no water and little or no oxygen.”
The bacteria are probably descendents of soil microorganisms that were trapped in the asphalt, according to Kim’s co-author and advisor David E. Crowley, a professor of environmental microbiology at UCR.
“Some may also have been carried to the surface in the heavy oil that seeped upwards from deep underground oil reservoirs,” Crowley added.
Kim and Crowley collected DNA from the microbes by first freezing globs of asphalt with liquid nitrogen (another great use of cryogenics), then grounding the mixture into a powder from which they extracted the DNA.
“Previously, some bacteria had been cultured from the asphalt, but no one had been able to extract DNA from the asphalt to study the entire microbial community,” Kim said.
Most of the more than 200 species of microorganisms identified by the researchers are being classified as new families, whose closest living relatives are able to survive in extreme environments including radioactive ones.
The results of their studies were published online in the April 6 issue of Applied and Environmental Microbiology , and a display about the discovery is currently at the La Brea Tar Pits' Page Museum in Los Angeles.