A microbiological study of the self-cleaning potential of oily Arabian Gulf coasts.
OBJECTIVE
Due to the active production and transport of crude oil in the Arabian Gulf region, the Arabian Gulf coasts are routinely polluted with oil. Therefore, such coasts have been subject of studies aiming at assessing the roles of indigenous microbial consortia in cleaning these environments. In the present study, epilithic microbial communities along Kuwait coasts were studied for their oil degradation potential.


METHODS
Gravel particles coated with deep green biofilms were collected from four coastal sites in autumn, winter, and spring. Phototrophs in these consortia were determined in terms of their chlorophyll a contents and identified by their morphological characteristics. Total bacteria were counted microscopically and cultivable bacteria by the dilution plating method on nutrient agar as well as on inorganic medium containing oil as a sole source of carbon and energy. The bacterial community structures were also characterized and compared by denaturing gradient gel electrophoresis (DGGE).


RESULTS
Epilithic biomass samples from the four sites in the three seasons were rich in diatoms and picocyanobacteria as well as total bacteria. Direct counting gave bacterial numbers per square centimeter gravel surface of 2 to 6 x 10(7) cells depending on the sampling site and season. Cultivable bacterial numbers on nutrient agar and crude oil as a sole source of carbon were 3 x 10(3) to 8 x 10(4) and 1 x 10(3) to 7 x 10(3) cells/cm(2) gravel surface, respectively. The DGGE profiles of epilithon biomass samples revealed major 16S rDNA bands that matched bands of pure oil-utilizing bacterial isolates.


CONCLUSIONS
The microbial communities showed a degree of consistency in all sites and seasons.


CONCLUSIONS
The microbial consortia coating gravel particles are potentially suitable tools for self-cleaning of oily Gulf coasts. They are rich in oil-utilizing bacteria whose activities are probably enhanced by oxygen produced by the phototrophic partners in the consortia.


CONCLUSIONS
The combination of conventional microbiological analysis with molecular approaches gives an enhanced idea about natural microbial communities especially those with environmental application potential.
Mahmoud
Huda
H
Faculty of Science, Department of Biological Sciences, Kuwait University, P. O. Box 5969, 13060, Safat, Kuwait.
Al-Hasan
Redha
R
Khanafer
Majida
M
Radwan
Samir
S
D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018441:Biofilms; D018533:Biomass; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D019156:Indian Ocean; D010578:Petroleum / Q000032:analysis / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D012621:Seasons; D012623:Seawater / Q000737:chemistry / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D000077194:Chlorophyll A