Identification and Study of Polycyclic Aromatic Hydrocarbons (PAHs) Degradation Potential by Some Bacterial Isolates from Caspian Sea and Study of Possibility to Discover Novel Bacterial Species

Abstract

Background: are group of enviramental pollutants. These pollutants could be present in air, water and soil. Among neutralization ways of Polycyclic Aromatic Hydrocarbons (PAHs), biodegradation is very important. Because of high concentration of Them in Caspian sea, idetification of Caspian sea bacteria that are able to biodegrade PAHs is very important. Goals: 1. Isolation of some Caspian sea bacteria and qualitative study of Naphthalene, Phenanthrene and Anthracene biodegradation. 2. Idetification of bacteria, Study of biochemical characteristics of them and quantitive study of PAHs biodegradation. Methods: Isolation of bacteria from water sample was done using marine agar and sea water medium and in order to isolate bacteria able to degrade PAHs, ONR7a media supplemented with Naphthalene, Phenanthrene and Anthracene were used. Qualitative analysis of biodegradation of above compounds was done using three ONR7a supplemented media with one PAH as sole carbon source. For identification of bacterial isolates, 16S rRNA sequencing was used and quantitive study of degradation potential of these compounds was performed by UV analysis. Results: Five bacteria named SS2, SF2, SFR1, SFR2 (=SS1) and SFR3 with ability to use mentioned PAHs which belong to Pseudomonas, Shewanella, Photobacterium and Mycobacterium genera was isolated. Isolate SS2 has potential to be introduced as noval bacterial species. quantitive study of mentioned PAHs on SS1 and SS2 isolates belonging to Photobacterium and Pseudomonas genera, showed significant difference in comparison with control group in using these compounds as sole organic carbon source and in growing in presence of them. (p≤ 0.05) Conclusion: Bacteria of Caspian sea have an efficient role in biodegradation of PAHs and part of the purification process of Caspian sae from these pollutants, is done by bacteria.