Lipid profile: a useful chemotaxonomic marker for classification of a new cyanobacterium in Spirulina genus

The morphological, physiological and genetic characteristics of an isolate cyanobacterium from hard sand of the lake Venere in the Pantelleria island (Italy) were described. The isolate with a small-size coiled helix shape, g rowing optimally at pH 9.2-9.5 at 30 degrees C under continuous illuminatio n and aeration, possessed a 61.5 mol% of Guanine + Cytosine content of DNA. The lipid profile showed the presence of mono-, di-glycosyl, sulphoquinovo losyl and phosphatidyl (MGDG, DGDG, SQDG and PG). The Fatty acid profile wa s also studied, characterized by the absence of gamma-linolenic acid and th e presence of saturated and monounsaturated C16 and C18. The latter was als o present as a dienoic component. The fatty acid composition was affected b y growth temperature by increasing the degree of desaturation at a lower te mperature and the biosynthesis of shorter acyl chains. The effects of growt h conditions other than temperature. physical, nutritional and chemical on lipid composition were also studied. The overall features of the cyanobacte rium isolated from Pantelleria clustered it into Spirulina genus. (C) 2000 Elsevier Science Ltd. All rights reserved.