Cyanobacteria are present abundantly in rice fields and are important in helping to maintain rice fields fertility through nitrogen fixation and involved in the photosynthesis. The present study is aimed to investigate the ultrastructure of cyanobacterial cell wall, biochemical and pigment analysis of blue green algae were isolated from the paddy field of Vallampadugai and Keerapalayam, Cuddalore District and maintained in BG11 medium for 10 days. Scanning Electron Microscopic (SEM), Trasmission Electron Microscopic (TEM) and biochemical studies such as total carbohydrates, total lipids, total protein, total free amino acid, and photosynthetic accessory pigment such as chlorophyll a, phycocyanin, phycoerythrin and allophycocyanin were observed in Anabaena and Oscillatoria sp. at 10th day.
