台灣沿岸十六烷和環己烷的分解性細菌之多樣性研究

Abstract

飽和烴係原油含量最豐富的成分，可分為烷烴及環烷兩大類。為瞭解台灣沿岸海域中，具分解此兩大類碳氫化合物能力之細菌種類，本研究以含有烷烴或環烷為單一碳源進行增菌培養，最後分離出可利用十六烷或環己烷作為單一碳源之細菌共計32株﹔將分離株之16S rDNA以四種限制酶（DdeI、RsaI、HhaI 和ScaI） 進行RFLP分析，初步可分為13種基因型。各基因型代表株經16S rDNA片段序列分析後，大致可歸類為Marinobacter、Vibrio、Shewanella、Pseudoalteromonas、Halomonas、Pseudomonas、Prolixibacter、Alcanivorax等屬之細菌，依初步生理生化特性及序列分析，其中編號為HD54的分離株可能為新屬細菌。 HD54經16S rRNA 基因比對，與Prolixibacter bellariivorans F2T序列相似度為89.4 %。HD54為不具鞭毛、無運動性、好氧、具觸酶及氧化酶活性之革蘭氏陰性桿菌，最適合生長於30 ℃及含2.5 % NaCl的培養基中。HD54與 Prolixibacter bellariivorans F2T於親緣演化關係與生理、生化特性有明顯的差異，初步研判HD54應為新屬新種。 本研究顯示台灣沿岸海域可分解烷烴或環烷之細菌種類實屬多樣，其中可能極具應用潛力，未來值得深入探討與研究。

Saturated hydrocarbons, including alkanes and cycloalkanes, constitute the largest fraction of crude oil by mass. In this study, the water samples were cultured in CM broth within hexadecane or cyclohexane. There were 32 isolates of bacteria which could degrade hexadecane or cyclohexane isolated from northeast coast, Shiangshan and South Bay. It could be classified into thirteen genotypic groups by the RFLP analysis. According to the 16S rRNA gene sequencing results, these isolates belong to Marinobacter, Vibrio, Shewanella, Pseudoalteromonas, Halomonas, Pseudomonas and Prolixibacter. Phenotypic and phylogenetic data of the isolates reveal that one isolate, HD54, could be novel genus. Strain HD54 was non-motile, non-flagellated, rod-shaped, pink-orange bacterium. Cells were gram negative, aerobic, catalase- and oxidase-positive. On the basis of 16S rRNA gene sequence phylogeny Prolixibacter bellariivorans is only 89.4 % similar to HD54. Results from physiological, biochemical and phylogenetic analysis showed that HD54 should be classified as a novel genus and species within the phylum Bacteroidetes. This study showed high diversity of bacteria degrading hexadecane or cyclohexane in coastal waters of Taiwan. It might have the potential of applicability. It is worth to study further in the future.