Spirulina is the most important commercial microalga for the production of biomass as health food and animal. It is mainly oriented towards the health food market, utilizing a chemically defined medium. In the present study, four strains of Spirulina platensis were isolated from various locations and designated as SP1, SP2, SP3, SP4, and successfully cultivated in different liquid media like Zarrouk’s medium, seawater enriched (SEM) with different amount of NaHCO3, NaNO3, K2HPO4 medium and seawater medium (SW). In Spirulina platensis the biomass concentration, protein, lipid content, chlorophyll and total carotenoids were monitored for 30 days on 10 days interval basis. Among the four strains SP4 recorded the best growth in all types of medium. From the three different media SP4 showed the highest biomass (dry weight) concentration, protein and lipid content in Zarrouk’s medium (0.362 mg ml-1, 0.234 mg ml-1 & 6.85%) followed by seawater enriched medium (0.334 mg ml-1,0.201 mg ml-1 & 6.49%) and seawater medium (0.283 mg ml- 1,0.146 mg ml-1 & 5.93%). High level of chlorophyll and total carotenoid were estimated in Zarrouk’s medium (31.90 µg ml-1& 6.65 µg ml-1) followed by seawater enriched medium (28.71 µg ml-1& 5.93 µg ml-1) and lowest amount was recorded in seawater medium (25.21 µg ml-1 & 4.71 µg ml-1). The results of present investigation revealed the potential use of seawater with some nutrients for commercial cultivation of Spirulina platensis at low cost.
