Municipal Wastewater Enriched with Trace Metals for Enhanced Lipid Production of the Biodiesel-Promising Microalga Scenedesmus obliquus

In the present study, the effect of trace metal nutrients on biomass and lipid productivity of Scenedesmus obliquus cultured in municipal wastewater was evaluated. Lipid productivity of S. obliquus significantly increased by 18.63%, 19.21%, and 27.95% by adding trace metals of Mo, Mn, and Fe, respectively, with the highest lipid productivity of 24.69 mg/(L center dot d) in case of Fe (3.00 mg/L FeSO4 center dot 7H(2)O). GC analysis of the lipids showed that the control (WW) and ferrous sulfate-treated cultures had very similar compositions, and both of them contained considerable proportions C16-18, showing their suitability for biodiesel production. Moreover, using FeSO4 center dot 7H(2)O enhanced the removal rates of total phosphorus, ammonia nitrogen, and total nitrogen in municipal wastewater, which attained 94.7%, 99.2%, and 95.8%, respectively.