| Due to the toxicity such as carcinogenic, mutagenic, teratogenic and the characteristic of hard-degrading, polycyclic aromatic hydrocarbons (PAHs) have been menaces to human healthy and ecological safety. The various habitats in ocean probablely made the selections and diversities of the PAHs-degraders.In this study, through in situ enrichment or simulating the in situ enrichment, we analysed the diversities of PAHs-degraders from the difference coastal seas and deep-sea. The resultes are as follow(1)Diversity of PAHs-degrading bacteria in the coastal sea of Xiamen Island: phenanthrene was serviced as sole carbon source coated on PVC plates that were employed as PAHs carriers.After 7d' enrichment by suspending the plates in seawater near the Xiamen Cruise Dock in control with PVC plates clear of phenanthrene, phenanthrene-degrading bacteria were expected to grow on the surface of the coated phenanthrene. The bacterial films on the two kinds of plates were scrapped and collected, and subjected to bacterial diversity comparison. With two culture-independent methods, DGGE and 16S rRNA gene library construction, the bacteria of genus Cycloclasticus was found to be the predominant member in the bacterial film grew on the PAHs coated surface, which account for 50% of the total clones in the library.(2)Diviersity of PAHs-degrading bacteria in the sediments of Beibu Bay: PAHs-degrading consortia were enriched by using naphthalene,phenanthrene and pyrene as sole carbon source and energy source, respectively.32 strains were isolated; they mainly belonged to genus Pseudomonas,Marinobacter, Alcanivorax and Novosphingobium. DGGE and 16S rRNA gene library were used for further analysis of the consortia. Pseudomonas dominated the PAHs-degrading consortia of site 7#, which accounted for 67% of the clone library. In the PAHs-degrading consortia of site BC-2, the genus Novosphingobium was predominant, accounting for 60% of the clone library. Subsequently, a potential new strain Novosphingobium sp.BC2-1 was obtained. The highest similarity of the 16S rRNA gene sequence with the type strain Novosphingobium naphthalenivorans TUT562T was lower than 96%.According to the a-subunit gene sequence of the initial dioxygenase of PAHs, a pair of degenerate primers was desiged and 623 bp fragment was obtained by PCR. Analysis showed that it was similar to the bphA1F gene of N. aromaticivorans F199T, with the similarity as 99%. The degrading rates of strain BC2-1 to naphthalene,phenanthrene, acenaphthene,fluorene, anthracene and pyrene were determined by GC-MS.After 10d' incubation, the degradation rates to naphthalene,fluorene and phenanthrene were higher than 80%, to acenaphthene and anthracene were about 40%. However, a poor degradation was found to pyrene.(3)Study of the oil-degrading consortia from deep-sea water of Indian Ocean at low temperature:Use the oil as sole carbon source to enrich the oil-degrading strain in 4℃environment. Combined the DGGE with isolation of strains, we analysed the structure of consortia and dynamic of the degrading process.Subsequently, we identified the oil-degrading ability of the isolated strains.The results showed that cultivable bacteria mainly belong to genus Alcanivorax, Cobetia, Halomonas, Pseudoalteromonas, Psychrobacter and Marinobacter. Dynamic of oil-degrading process showed the genus Alcanivorax was the predominance of the consortia in the entire process.Five strains have the oil-degrading capability in 4℃environment. The strain belong to genus Alcanivorax has the highest oil-degrading ability among the five strains.
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