Isolation and characterization of bacteria in aged coastal seawater from north Taiwan
Date Issued
2015
Date
2015
Author(s)
Yeh, Yu-Ting
Abstract
The distribution of nutrients in marine environments is usually uneven, and varys between seasons and regions, but on a whole, the ocean is a vast, low-nutrient environment. To further understand the marine bacteria able to survive in low nutritious environments, we isolated, purified and analyzed the bacteria in the aged seawater samples collected from northern Taiwan which have been stored for more than 7 years. We isolated 25 isolates from the samples, and according to the sequences of 16S rRNA gene, they belong to the following genera: Stappia(6 isolates)、Alteromonas(4 isolates)、Oceanococcus(2 isolates)、Marinobacter(3 isolates)、Mesorhizobium(1 isolate)、Alcanivorax(4 isolates)、Kangiella(1 isolate)、Halobacillus(1 isolate)、 Spongiibacter(1 isolate)、Erythrobacter(1 isolate)and Marinobacterium(1 isolate). According to the physiological and biochemical tests, we found that all the isolates are negative for glucose fermentation, indole and H2S production, and can grow under 1-5% NaCl、pH 8-9 and 25-30°C. Based on the 16S rRNA sequence, the similarity between Na1 and Spongiibacter tropicus CL-CB221T is 95.9%. Na1 is a sea salt-needing, aerobic and gram’s negative bacteria, and the optimal range for growth is 30-37°C, 1-3% NaCl and pH7-8. Na1 may be a novel bacterium of genus Spongiibacter according to the cross- matching between the study and reported data. In order to understand the proliferation of the isolates in low-nutrietion environment, we cultivated isolates N1C and N2B in medium, and observed the enumerational change by plate count method. The results showed that the two isolates are able to grow rapidly in a medium with carbon source of 40 mg / L.
Subjects
nutrient
low-nutrient medium
plate count method
SDGs
Type
thesis
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