2.1 Collection and preparation of sample
Phormidium ambiguum  Gomont was collected from the Edakkad beach, Kannur Dist, Kerala, (GPS coordinates 11°49’09.9”N 75°25’02.9”E) from a depth of 0.5 to 1 m. The washed cyanobacterial biomass was grinded to fine paste, dried under vacuum and stored at -20 ºC.