Extracellular Polymeric Substances from Cyanobacteria: Characteristics, Isolation and Biotechnological Applications-A Review

Cyanobacterial Extracellular Polymeric Substances(EPS) play an important physiological role in mat formation and stress tolerance during adverse conditions. They are highly heterogeneous polymers containing a number of distinct polysaccharides and non carbohydrate constituents including proteins, phospholipids and nucleic acids. EPSs are therefore regarded as abundant source of structurally diverse polysaccharides. Some of these possess unique properties for special applications in bioremediation, food, and pharmaceutical industries. Their physical and chemical characteristics show little variability and they are not vulnerable to variations in climatic, cultivation, production or pollution conditions and are secreted in harsh environment. For these reasons, they are good candidates for mass production on an industrial scale and therefore show immense biotechnological potential. Considerable progress has been made in isolation,and characterisation of new cyanobacterial EPSs that possess numerous benefits and are of industrial significance This paper attempts to highlight these developments with a view to increase the inventory of bioactive compounds whose exploitation will lead to development of clean technologies utilising cheap ,desirable and renewable resources such as carbondioxide and solar energy through photosynthesis that cyanobacteria are capable of. Key WordsCyanobacteria, Extracellular Polymeric Substances