There have been many papers published on the abilitiy of certain bacteria
to degrade hydrocarbons from petroleum products. These bacteria are
capable of doing this because they have the necessary enzymes to break
the aromatic rings of polyaromatic compounds (a major constituent of
petroleum products). For example, many species of the genus Pseudomonas
are capable of degrading alkylaromatics to alkylcatechols, and then
following ring fission of this subsituent and some more catabolic
activity the intermediate products pyruvate and acetyl-coA are produced,
which are readily degraded by the bacteria through the TCA cycle to the
end products carbon dioxide and water. This is definietely an ideal
situation and has been shown to occur in the laboratory. However, the
natural environment of the soil is much more complicated and may not
produce these ideal results. Other genus to look at are: Rhodocccous,
Psychrobacter, and Bacillus. To apply this to a large scale, such as an
oil spill, would require huge amounts of bacteria, and in many cases, the
bacteria will require additional nutrients/supplements to keep them
actively metabolizing the petroleum. In many cases, to acquire an
efficient biodegradation would require continuous aeration/agitation to
supply oxygen for the actively metabolizing bacteria. And what of the
impact of spraying billions and billions of bacteria into an
environment. There would be a disturbance of the natural microbial
ecology that could possibly have repercussive effects on the local
population of animals. Especially if it can cause illness in humans and
animals (many hydrocarbon-degrading bacteria are very pathogenic, for
example P. cepacia, P. fluorescens, P. aeruginosa, B. cereus, and B.
anthracis). So, all these factors (environmental impact and human health
effects) and more have to be considered when dealing with large scale
bioremediation projects. There is little risk of any damage to asphalte
etc... because the bacteria, being microscopic in size, would take a very
long time to make any impact on the structural integrity of the road.
There has also been research into genetically-engineering a bacterium for
optimal performance with minimal side effects. There is much hope in the
future of bioremediation.
I hope that has enlightened you on the aspects of bioremediation.
Mike Busse
mikebusse at home.com
Albert Jackson Saur wrote:
> I am writing for information. Many years ago I read that some French
> scientists had developed a strain of bacteria that could metabolize
> petroleum. Their goal was to provide a cheap source of food.
>> Some years later I met a man who had retired from a laboratory for a
> major automobile manufacturer. He had developed bacteria that would
> metabolize used oil and expected that they would be used to convert
> crank-case drainings from cars to something that could be used or
> disposed of in an environmentally safe way.
>> I have often thought about using such bacteria in cleaning up major
> oil spills, such as the disaster near Valdez, Alaska. Does anyone
> know about such bacteria?
>> I suppose also that one would have to be careful that such bacteria
> didn't get loose to go to work on some highways and many city streets,
> all composed of petroleum by-products.
>> I am not a biologist. I am merely a retired physicist. This inquiry
> is just to satisfy my curiosity.
>> Sincerely,
>> Albert J. Saur
> <alsaur at igc.org>
