Nanobiotechnology of cyanobacterial UV-protective compounds: innovations and prospects

Abstract Cyanobacteria synthesize novel secondary UV-protective metabolites such as mycosporine-like amino acids (MAAs) and scytonemin. MAAs are composed of aminocyclohexenone or an aminocyclohexinimine chromophore conjugated with the nitrogen substituent of an amino acid or its amino alcohol and are small, water soluble, and colorless compounds. The extracellular polysaccharide sheath pigment scytonemin found in some cyanobacteria is a lipid-soluble dimeric pigment composed of indolic and phenolic subunits linked by an olefinic carbon atom. These compounds are highly photostable and act as potent photoprotectant and antioxidant. Inorganic nanoconjugates of these biomolecules could serve as a strong nontoxic, ecofriendly, biological sunscreen agent as they prolong their residence time in the target samples. Hence, future research must be focused on the investigation of facile, efficient, environmentally benign synthesis and use of these nanoparticle–biomolecule complexes in cosmetic and pharmaceutical industries as well as food industry to improve the shelf life of commodities.