Temperature and nutrient availability control growth rate and fatty acid composition of facultatively psychrophilic Cobetia marina strain L-2.
A facultative psychrophilic bacterium, strain L-2, that grows at 0 and 5 degrees 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 degrees 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 degrees 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 degrees C, strain L-2 grew better in complex than in defined medium. Furthermore, when the growth temperature was shifted from 0 to 5 degrees 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 degrees 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.
Yumoto
Isao
I
Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology, 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, 062-8517, Japan. i.yumoto@aist.go.jp
Hirota
Kikue
K
Iwata
Hideaki
H
Akutsu
Masatoshi
M
Kusumoto
Keita
K
Morita
Naoki
N
Ezura
Yoshio
Y
Okuyama
Hidetoshi
H
Matsuyama
Hidetoshi
H
D002462:Cell Membrane / Q000378:metabolism; D003080:Cold Temperature; D003470:Culture Media; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000378:metabolism; D044129:Halomonadaceae / Q000145:classification / Q000254:growth & development* / Q000378:metabolism*; D013696:Temperature
D003470:Culture Media; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated