Cyanobacteria: a Potential Natural Source for Drug Discovery and Bioremediation

Cyanophyta or cyanobacteria are a phylum of bacteria which obtain their energy by performing photosynthesis. Cyanobacteria are the oldest photosynthetic organisms that evolved on Earth approximately 2.6 to 3.5 billion years ago (Hedges, et al., 2001). They are generally called as bluegreen algae, which is a misnomer, as cyanobacteria are prokaryotic and algae are eukaryotic (Allaby, 1992). Cyanobacteria are morphologically diverse, existing as free-living or colonial or forms symbiotic relationships with plants or with lichen-forming fungi or with other organisms (Al-Thani, 2015). Their colonies will be in the form of filaments, sheets, or even hollow balls (Burja, et al., 2001). They are diverse (Klymiuk, et al., 2014) and Omni present on earth and their habitats range from geothermal hot springs, volcanic vents etc., to frozen ponds of Antarctica and from marine to terrestrial ecosystems (Panosyan, 2015). Cyanobacteria have evolved many adaptations to survive, compete and achieve dominance in different environments (Rastogi and Madamwar, 2015; Menamo and Wolde, 2015). It is hypothesized that photosynthetic organelle evolution in eukaryotes is by the process of endosymbiosis between a phagotrophic host and a cyanobacterium (Cohen, et al., 1986). Each individual cell of a cyanobacterium has a thick gelatinous cell wall but lacks flagella, but hormogonia of some species helps in gliding movement along surfaces. ABSTRACT