Temperature and nutrient availability control growth rate and fatty acid composition of facultatively psychrophilic Cobetia marina strain L-2
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- 作者：Isao Yumoto ; Kikue Hirota ; Hideaki Iwata ; Masatoshi Akutsu ; Keita Kusumoto ; Naoki Morita ; Yoshio Ezura ; Hidetoshi Okuyama and Hidetoshi Matsuyama
- 关键词：Facultative psychrophile ; Cobetia marina ; cis ; Unsaturated fatty acid ; trans ; Unsaturated fatty acid ; Cold adaptation
- 刊名：Archives of Microbiology
- 出版年：2004
- 出版时间：May 2004
- 年：2004
- 卷：181
- 期：5
- 页码：345-351
- 全文大小：216 KB
文摘
A facultative psychrophilic bacterium, strain L-2, that grows at 0 and 5°C as minimum growth temperatures in complex and defined media, respectively, was isolated. On the basis of taxonomic studies, strain L-2 was identified as Cobetia marina. The adaptability of strain L-2 to cold temperature was higher than that of the type strain and of other reported strains of the same species. When the bacterium was grown at 5–15°C in a defined medium, it produced a high amount of trans-unsaturated fatty acids. By contrast, in a complex medium in the same temperature range it produced a low amount of trans-unsaturated fatty acids. In the complex medium at 5°C, the bacterium exhibited a three-fold higher growth rate than that obtained in the defined medium. Following a temperature shift from 11 to 5°C, strain L-2 grew better in complex than in defined medium. Furthermore, when the growth temperature was shifted from 0 to 5°C both the growth rate and the yield of strain L-2 growing in complex medium was markedly enhanced. These phenomena suggest that an upshift of the growth temperature had a positive effect on metabolism. The effects of adding complex medium components to the defined medium on bacterial growth rate and fatty acid composition at 5°C were also studied. The addition of yeast extract followed by peptone was effective in promoting rapid growth, while glutamate addition was less effective, resulting in a cis-unsaturated fatty acid ratio similar to that of cells grown in the complex medium. These results suggest that the rapid growth of strain L-2 at low temperatures requires a high content of various amino acids rather than the presence of a high ratio of cis-unsaturated fatty acids in the cell membrane.