جداسازي، شناسايي مولكولي Alcanivorax dieselolei ‏از خليج فارس و بررسي قابليت تجزيه زيستي آن براي پاك‏سازي آلودگي نفتي

Isolation, and molecular detection of Alcanivorax dieselolei in the Persian Gulf and the study of biodegradation ability for remediation of oil pollution

مقدمه: آلودگي نفتي در محيط‏‏ها‏ي دريايي، مساله‏اي جهاني است. ميكروب‏ها‏ي تجزيه كننده هيدروكربن دريايي اجباري اخيراً شرح داده شده اند. يك عضو اصلي از اين خانواده Alcanivorax بوده كه در محيط‏ها‏‏ي دريايي پس از دو هفته از نشت نفت غالب مي‏شود. مواد و روش‏ها‏: در اين تحقيق، ابتدا از مناطق آلوده به نفت در خليج فارس نمونه برداري شد. باكتري‏ها‏ در محيط ONR7a غني سازي شدند و كلني‏ها‏ روي محيط مارين اگار خالص‏سازي شدند. تمام كلني‏ها‏ براي قابليت تجزيه نفت خام غربال‏گري شدند. شناسايي مولكولي با تكثير ژن 16S rDNA و تعين توالي انجام شد. نتايج: در مجموع 11 كلني كه قادر به تجزيه نفت خام بودند، جداسازي شدند. سويه‏ها‏ي PG-24 و PG-12 رشد بالاتري روي نفت خام نشان دادند. شناسايي مولكولي همساني 99 درصد‏‏ با ‏Alcanivorax dieselolei از اين دو سويه را نشان داد. اين دو سويه قادر به رشد روي هيدروكربن‏ها‏ي اليفاتيك بودند و بالاترين رشد روي C16 و C18 مشاهده شد. تجزيه نفت خام به‏وسيله اين دو سويه 85 درصد‏ پس از پنج روز بود. بحث و نتيجه‏گيري: اين اولين گزارش از جداسازي جنسAlcanivorax در خليج فارس است. مطالعه بيشتر اين باكتري‏ها‏ و بهينه سازي تجزيه آلودگي‏ها‏ي نفتي مي‏تواند نقش مهمي در تعديل آلودگي نفتي خليج فارس ايفا نمايد.

Introduction: Oil pollution in marine environments is a global problem. The Persian Gulf is a specific region because over than 60 % of world crude oil transports through the strait of Hormoz. Obligate marine hydrocarbon-degrading microbes have been recently reported. Alcanivorax, a member of this family is predominant in oil polluted sea. Materials and Methods: In this survey, seawater samples were collected from oil contaminated regions in the Persian Gulf. Bacteria were enriched in ONR7a medium and colonies were purified in marine agar and ONR7a media. All colonies were screened for ability to degrade crude oil. Molecular identification was carried out by amplification of 16S rDNA gene and sequencing analysis. Also, biodegradation of some hydrocarbon and crude oil were analyzed. Results: Totally, eleven different colonies were isolated that were able to degrade crude oil. Two strains (PG-24 and PG-12) showed higher growth rates on crude oil than other strains. Molecular identification showed 99% homology of these two strains with Alcanivorax dieselolei. These two strains could grow on aliphatic hydrocarbon and the highest growth rates were observed on C16 and C18 substrates, also 80 % of crude oil was degraded. Discussion and Conclusion: This article is the first report on isolation of Alcanivorax genus from the Persian Gulf, thereby further studies and optimization of biodegradation of oil pollution by these bacteria are important for modulate oil pollution in the Persian Gulf. Key words: Biodegradation, Alcanivorax, Optimization, Oil pollution, Persian Gulf