Isolation and cellular fatty acid composition of psychrotrophic Halomonas strains from Antarctic sea water

Abstract

Microorganisms from extreme environments such as Arctic, Antarctic and Polar regions modulate their membrane fatty acids to survive in such habitats. Characterization of such microorganisms helps in understanding their physiological behavior. In view of this, the present article describes isolation, characterization and cellular fatty acid composition of three bacterial isolates from Antarctic sea water samples. All the three isolates (BRI 6, 29 and 31) were psychrotrophic Gram negative rods. Their 16S rRNA sequencing (around 1200 bp) revealed that all three of them belong to genus Halomonas. Each of them showed 99% sequence similarity to Halomonas neptunia Eplume1 (NR 027218), H. boliviensis LC1 (NR 029080) and H. variabilis DSM 3051 (NR 042068). The fatty acid analysis of our isolates indicated i) predominance of C 18:1, C 16:0 and C16:1 fatty acids and absence of trans fatty acids in all of them and ii) higher percentage of anteiso fatty acids than of iso fatty acids in BRI 6. These characteristic features may contribute to their adaptation to the Antarctic habitat.

Keywords

• 16S rRNA
• halotolerant
• polyunsaturated fatty acids
• omega- 6 fatty acids
• cold adaptation