福爾摩沙峽谷與澎湖峽谷以及高屏斜坡沉積物細菌的分離和特性研究

Abstract

本研究的目標在於進行台灣西南海域福爾摩沙峽谷與澎湖峽谷以及高屏斜坡等樣區沉積物中細菌的分離與特性探討。以平板計數法 (plate count method) 估得這三個樣區細菌生菌數介於5.8 × 103 – 3.7 × 104 cfu/g wet wt. (菌落數/每克沉積物)。從三樣區沉積物分離出菌株數分別為福爾摩沙峽谷54株、澎湖峽谷41株、高屏斜坡13株，三者合計108株。分離株生理、生化特性檢測結果顯示革蘭氏陰性和陽性細菌分佔其中29.6 % 及70.4 %，所有分離株皆可生長於pH 6 – 8及25 – 30℃，皆呈觸酶陽性反應，皆無法產生吲哚；牠們多可生長於42 ℃ (89.8 %)，且多可藉由硝酸還原或脫氮進行無氧生長 (95.4 %)。根據生理、生化特性差異挑選13 株分群代表株進行16S rRNA基因定序比對，結果顯示這些分離株分別為屬於Marinobacter （1株）、Pseudoalteromonas （2株）、Halomonas （2株）、Halobacillus（1 株）、Staphylococcus（1株）、Fictibacillus（1 株）Lysinibacillus（1 株）以及Bacillus（4株）等屬菌種。整體而言，福爾摩沙峽谷、澎湖峽谷以及高屏斜坡沉積物所含細菌以厚壁菌門 (Firmicutes) 中芽孢桿菌屬 （Bacillus） 比例最高 (50.0 %)；其次是變形菌門 (Proteobacteria)中γ – 變形菌綱 (Gammaproteobacteria)的假交替單胞菌屬Pseudoalteromonas (22.2 %)。另外，福爾摩沙峽谷、澎湖峽谷及高屏斜坡三樣點沉積物中細菌組成相似，樣本中皆能發現Pseudoalteromonas、Halomonas、Bacillus及Fictibacillus等四屬菌株，Marinobacter屬菌株僅在高屏斜坡樣本被分離出，而Halobacillus則僅在澎湖峽谷樣本中發現。

The aim of this study was isolation and characterization of bacteria in the sediments of Formosa and Penghu submarine canyons and Kaoping slope. The bacterial abundance in the sediments ranged from 5.8 × 103 to 3.7 × 104 cfu/gwet wt. by plate count method. One hundred and eight bacterial strains were isolated from the sediments in the three areas : Formosa submarine canyon (54 strains), Penghu submarine canyon (41 strains) and Kaoping slope (13 strains). The results of the physiological and biochemical tests showed that 29.6 % of the strains were gram negative bacteria and 70.4 % of the strains were gram positive bacteria. All of the strains could grow at pH 6 – 8 and 25 – 30 °C, but all of them could not produce indole; most of the strains (89.8 %) were catalyst positive reactive and most of them (95.4 %) could carry out the nitrate reduction or denitrification under anarobic condtions. Moreover, 89.8 % of the isolated strains could grow at 42 °C. According to the physiological and biochemical characteristics, 13 strains were selected by primary classification for the consequent phylogenetic analysis of the 16S rRNA gene. The sequence results showed that these representivestrains belonged to Marinobacter (1 strain), Pseudoalteromonas (2 strains), Halomonas (2 strains), Halobacillus (1 strain), Staphylococcus (1 strain), Fictibacillus (1 strain), Lysinibacillus (1 strain) and Bacillus (4 strain). The bacterial communities in the sediments of Formosa and Penghu submarine canyons and Kaoping slope mainly dominated by Bacillus (50.0 %) in the phylum Fimicute and followed by Pseudoalteromonas (22.2 %) of the class Gammaproteobacteria in the phylum Proteaobacteria. Moreover, the bacterial composition of three samples in Formosa submarine canyon, Pehghu submarine canyon and Kaoping slope were similar. Pseudoalteromonas, Halomonas, Bacillus and Fictibacillus were found in these three samples. The strains of Marinobacter were only found in the Kaoping slope sample, and Halobacillus was only found in the Penghu submarine canyon sample.