Abstract
A polyphasic approach was employed to describe a unicellular coccoid cyanobacterium isolated from Terraat El Khashab, Helwan, Egypt. The cells were characterised by their small diameter (1.9-2.2 mu m) and lack of buoyancy. The cultures grew best at a temperature range of 20-40A degrees C and moderate light intensity (20-50 mu mol photon m(-2) s(-1)). To verify its cyanobacterial nature, sequencing of 16S rRNA gene using cyanobacterial specific primers was performed followed by a phylogenetic analysis. The sequence best-matched Synechocystis sp. PCC6803 with 90% similarity. The phylogenetic analysis placed the isolate within a major clade containing different Synechocystis isolates. The fatty acid composition was rich in saturated fatty acids while polyunsaturated fatty acids were scarce. The phytochemical screening revealed the presence of flavenoids, alkaloids and saponins and absence of tannins. Vitamin C was also present in a considerable quantity. Some of the lipophilic fractions showed antimicrobial bioactivity against several pathogens. The pure bioactive compound from highest bioactive fraction was identified as oleic acid amide (M.wt.281) using chemical analyses including FT/IR, UV, proton H-NMR and GC-mass. The study highlights the importance of investigating the biotechnological potential of microorganisms inhabiting unusual niches.