Evaluation of Freshwater Microalgal Isolates for Growth and Oil Production in Seawater Medium

Microalgal cells have the potential to rapidly accumulate lipids which find applications as biodiesel production and nutraceuticals (e.g., EPA and DHA). Seawater is considered as an attractive medium for cultivation of microalgae since it contains most of the mineral nutrients. Besides, it offers the advantage of lesser bacterial and fungal contamination which is the main cause of decreased biomass productivity in open pond cultivation of freshwater microalgae. The present work describes the screening of freshwater microalgal isolates for production of biomass and lipids in a seawater based medium against freshwater medium under phototrophic cultivation. Isolate RAP-13, RI67-1 and R167-3 had maximum biomass production, whereas lipid yield was highest in the isolate RAP-13(67 mg/l). The potent isolate RAP-13 identified as Chlorococcum sp., was able to grow under a wide range of pH (4–10) in the seawater medium. Freshwater microalgae adapted well and yielded more lipids in seawater medium indicating the potential to cultivate them in marine water reducing the freshwater footprint.