Algal culture collections are specific repositories for living organisms and play a crucial role in phycology and microbiology as they are a source of high quality research material. Moreover, culture collections also serve purposes in education, ex-situ conservation and industry, e.g. production of biofuels or dietary supplements. Present study conducted from December 2009 to November 2010. Marine diatom, Skeletonema costatum were collected from Vellar estuary and cultured at CAS in Marine Biology, Annamalai University in India. One species of marine diatom, Skeletonema costatum (Bacillariophyceae) were commercially cultured in laboratory conditions