Abstract

Cyanobacteria are the main component of microbial populations fixing atmospheric nitrogen in aquatic as well as terrestrial ecosystems, especially in wetland rice-fields, where they significantly contribute to fertility as natural biofertilizers. Cyanobacteria require solar radiation as their primary source of energy to carry out both photosynthesis and nitrogen fixation. The stratospheric ozone depletion which has resulted in an increase in ultraviolet-B (UV-B; 280 - 315 nm) radiation on earth’s surface has been reported to inhibit a number of photochemical and photobiological processes in cyanobacteria. However, certain cyanobacteria have evolved mechanisms such as synthesis of photoprotective compound scytonemin and their derivatives to counteract the damaging effects of UV-B. In addition this compound has anti-inflammatory and anti-proliferative potentials. This review deals with the role of scytonemin as photoprotective compound and its pharmacological as well as biotechnological potentials.

Key words: Cyanobacteria, biotechnology, ozone depletion, photoprotection, scytonemin, UV-B (280 - 315 nm) radiation.

Abbreviation

Abbreviations: CCs, Chlorocarbons; CFCs, chlorofluro-carbons; HPLC, high performance liquid chromatography; OBS, organobromides; PAR, photosynthetically active radiation; UVR, ultraviolet radiation.