Bioprospecting antioxidants in some non-heterocystous filamentous cyanobacteria inhabit water bodies of semi-arid Rajasthan in India

Cyanobacteria are ancient photosynthetic organisms inhabitant of various habitats including arid and semi- arid water bodies. These are effective producers of various biologically active compounds that have been widely used in food, medicine, cosmetics and pharmaceutical industry. However, non-heterocystous cyanobacteria of arid and semi- arid water bodies are less explored for biotechnological applications. The aim of the present study was to investigate non-heterocystous filamentous cyanobacteria of freshwater bodies of semi-arid region for their pigment profile, phenolic contents and antioxidant properties. Our results revealed that among 8 cyanobacterial strains, D. tharense AT2015/7 and S. subsalsa AT2016/1 possessed higher amount of valuable pigments, phenolic contents and also showed good antioxidant properties. S. subsalsa AT2016/1 was the most promising cyanobacterial taxa for the production of phycocyanin when compared to so far studied non-heterocystous cyanobacteria inhabit aquatic habitats. In the LC-HRMS/MS analysis, 11 phenolic compounds were tentatively identified in D. tharense AT2015/7 and nine phenolic compounds detected in S. subsalsa AT2016/1. The present study revealed that cyanobacteria thriving in the semi-arid region could be promising candidates for the production of valuable pigments, phenolic compounds and could be a potential source of antioxidants.