Shewanella sp. GA-22, a psychrophilic hydrocarbonoclastic antarctic bacterium producing polyunsaturated fatty acids.
OBJECTIVE
The effects of different growth media and temperature on production of polyunsaturated fatty acids (PUFA) by Shewanella sp. GA-22 were investigated. The attempts to characterize the GA-22 genes, homologous to those of PUFA biosynthesis gene cluster, was performed.


RESULTS
Physiological and phylogenetic characterization of new Antarctic isolate GA-22 was performed. Total fatty acids were isolated from the cells growing under different conditions and analysed by gas chromatography-mass spectrometry (GC-MS). Using degenerated primers derived from the conserved regions within PUFA fatty acid synthase operons, five fragments of homological genes were amplified from GA-22 DNA, and two of them corresponding to pfaA and pfaC synthase subunits were sequenced.


CONCLUSIONS
Strain GA-22 was shown to be able to produce three different PUFA: linoleic, arachidonic and eicosapentaenoic acids. The PUFA production was temperature- and carbon source-dependent. The deduced gene products exhibited high similarity to corresponding fatty acid synthases PfaA and PfaC.


CONCLUSIONS
The PUFA production was detected on media supplemented with crude oil, gasoline and n-tetradecane. The apparent conservation of PUFA genes may point to the potential utilization of designed primers as functional markers in culture-independent ecological studies, and for initial screening in biotechnological fields.
Gentile
G
G
Istituto per l'Ambiente Marino Costiero, CNR Messina, Italy.
Bonasera
V
V
Amico
C
C
Giuliano
L
L
Yakimov
M M
MM
D000864:Antarctic Regions; D001483:Base Sequence; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D016415:Sequence Alignment; D020592:Shewanella / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D013696:Temperature; D014871:Water Microbiology
D003470:Culture Media; D004269:DNA, Bacterial; D005231:Fatty Acids, Unsaturated; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S