Azoarcus tolulyticus
Omar Rana

   

Toluene (methyl benzene) is used in lead free gasoline, paints, coatings, and resins.  Health effects include CNS depression, and damage to the lungs, liver, and kidneys.  As underground storage tanks age, gasoline leaks into surrounding soil.  The toluene found in gasoline can eventually end up in underground water supplies, making the water unfit for human consumption.

A solution to the pollution of water is bioremediation- the use of microorganisms to remove or detoxify toxic unwanted chemicals in an environment. Introducing a particular microbe to an environment can destroy pollutants.  Petroleum, for example, is under constant microbial attack when exposed to air and moisture. This natural reaction can be utilized to clean petroleum leaks and spills.  Through attempts to clean up infected water, toluene degrading microbes were isolated.

One such degrader is Azoarcus tolulyticus. This microbe, a 3.5 micron-wide, rod shaped bacterium, was isolated by Joanne Chee-Sanford.  Chee-Sanford, a graduate student from Michigan State University, found the organism in a contaminated aquifer. What sets A. tolulyticus apart from other toluene degraders is that the microbe is both aerobic and anaerobic.  When oxygen is not available, the bacterium uses nitrates. From an  environmental perspective, adding nitrates to an underground tank is easier than continuously pumping oxygen.  Scientists are currently working on  techniques to clean underground aquifers using A. tolulyticus.  By adding nitrates to the aquifers, the microbe will flourish, causing a faster toluene degradation rate.

A. Tolulyticus has also been used to clean up fluorinated organics.  Trifluoroacetic acid (TFA), the photochemical product of HCFC’s, can be decarboxylated by the microbe under certain conditions.

References

American Waterworks Association. Water Quality and Treatment., 4th ed. McGraw Hill, 1990.

Center for Microbial Ecology, Michigan State University.

Kerr, Robert S. Handbook of bioremediation. Lewis Publishers, 1994.

Madigan, Martinko, and Parker. Biology of Microorganisms, 8th ed. Prentice Hall, 1997.

Microbe Zoo.


*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.

 

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