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The microbes capable of cleaning
up the environment do their best work when a toxic chemical at
concentration that is not too high or too low surrounds them.
These microorganisms develop a taste for junk food.
This phenomenon is stimulating
new thinking about nature’s talent for detoxifying industrial
wastewater, coastal water and sediments. This approach is
called bioremediation or environmental biotechnology.
Baqar R. Zaidi, research
professor at the Department of Marine Sciences in
collaboration with Dr. Syed H. Imam, research chemist at USDA-ARS
research laboratory in Peoria, Illinois have been studying for
the past several years biodegradation of natural and synthetic
material and hazardous wastes. Zaidi has isolated several
bacteria capable of degrading nitrophenol, naphthalene and
phenanthrene from soil and coastal water in Guayanilla, Puerto
Rico. Included in the research were several strains that Zaidi,
while a postdoctoral researcher at Cornell University had
isolated from Cayuga Lake in Ithaca, New York.
By culturing each strain in a
series of sterile liquid diets with increasing large amounts
naphthalene, nitrophenol, phenanthrene and phenols, Zaidi
developed strains that could survive only if they had the
needed dose of the toxic soup. As the following table shows,
in non-sterile environment more like the real world, only the
bacteria isolated from local environment reduced the
concentrations to levels regarded nonpolluting.
|
Bacterial
strain |
Isolated
From |
Successful Inoculation into
Ind. Wastewater in PR |
|
Pseudomonas sp.
1 |
New Zealand soil |
No |
|
Pseudomonas sp.
2 |
Ithaca, N.Y. soil |
No |
|
Strain 3 |
Ithaca, N.Y. Activated sludge |
No |
|
Strain 5 |
Ithaca, N.Y. Activated
sludge |
No |
|
Strain 6 |
Ithaca, N.Y. Activated
sludge |
No |
|
Corynebacterium
Z-4 |
Ithaca, N.Y. Lake water |
Yes |
|
Pseudomonas
strain MS |
Soil in Guayanilla, PR |
Yes |
|
Pseudomonas
strain GR |
Soil in Guayanilla, PR |
Yes |
|
Pseudomonas
putida |
Soil in Guayanilla, PR |
Yes |
|
Corynebacterium
Z-2 |
Soil in Guayanilla, PR |
Yes |
|
Alteromonas sp. |
Guayanilla coastal
water(inoculated into seawater) |
Yes |
|
Strain M |
Mayaguez coastal water |
Yes |
|
Strain G |
Guanica coastal water |
Yes |
Until we did this
research, it was assumed that strains isolated from outside
Puerto
Rico can
successfully be used for bioremediation in tropical
environment. That assumption was wrong. This finding may
encourage more on-site bioremediation in tropical environment
by microbial strains isolated from Puerto Rico.
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