Application of Fe(NO3)3-based as nitrogen source and coagulant for cultivation and harvesting of Chlorella sorokiniana

In this study, Chlorella sorokiniana was successfully cultivated in the recycled medium whose nitrogen was supplied directly from the coagulant, Fe(NO3)3. With a dosage of 0.80g/L, harvesting efficiency of 95% could be achieved. What is more, this amount of nitrate in the coagulant was enough to fully support the growth of C. sorokiniana during the 8day cultivation period, almost as much as the initial nitrogen content in the BG11 culture medium. Other nutrients had to be supplemented, however, with at least 50% amount as in the BG11 recipe. C. sorokiniana culture grown in recycled medium replenished with 50% of nutrients showed much higher Fatty acid methyl esters (FAME) productivity than the control, with 88.3mg/L/day. The recycle of the medium is certainly a way of reducing the water footprint for the purpose of microalgae-derived biodiesel production; better still, it may serve to lower the nutrient footprint.