Expert: John Locke - 5/6/2010

Question
hi, i have this homework question that i cant seem to answer and need some help with

From your experimental data, you know that P.aeruginosa did not utilize any of the carbohydrates in the test media. In view of this, how do these organisms generate energy to sustain their viability?

Answer
Thanks for using AllExperts. Pseudomonas is a Gram negative, aerobic, non-motile, rod-shaped bacterium that is ubiquitous in the environment; it is renowned as a pathogen in hospitals and other health-care centers because of how common it is. Almost everything in the environment contains at least some Pseudomonas. The bacterium has a quite variable metabolism that does not depend on the presence of complex carbohydrates; it is occasionally observed growing in distilled water, so obviously it is quite robust in terms of its ability to survive. That said, the metabolism of Pseudomonas always involves oxygen--it does not ferment carbohydrates as many other bacteria do.

In the laboratory, the simplest medium for Pseudomonas requires only acetate as a carbon source and ammonium as a source of nitrogen. Pseudomonas can use more than fifty organic compounds as energy sources, so in the scenario you present, the bacterium need not be using any of the carbohydrates in the medium for growth. It may be using acetate (which is not a carbohydrate) and ammonium or some other simple organic compounds that are present in the agar, without needing to utilize the more complex carbohydrates in the test media. Regardless, it utilizes these compounds via aerobic metabolism.