Investigation of combined effect of nitrogen, phosphorus and iron on lipid productivity of microalgae Ankistrodesmus falcatus KJ671624 using response surface methodology

• Microalgae Ankistrodesmus falcatus was evaluated as potential biodiesel feedstock.
• Combine effect of nitrogen, phosphorous and iron evaluated on lipid productivity.
• Nitrogen was most influencing parameter for lipid productivity followed by iron.
• Photosynthetic behaviour validates high lipid productivity under stress condition.
• Nutrient stress enhanced lipid accumulation with suitable lipid profile.

Enhancement of lipid accumulation is essential to improve the commercial feasibility of microalgal biodiesel production. An oleaginous microalgal strain, Ankistrodesmus falcatus KJ671624 was evaluated for its potential as a biodiesel feedstock in this study. The collective effect of nutrient (nitrogen, phosphorous and iron) stresses on the lipid productivity of the selected strain was studied by response surface methodology. The highest lipid content of 59.6% and lipid productivity of 74.07 mg L−1 d−1 was obtained under nutrient stress with nitrogen 750 mg L−1, phosphorus 0 mg L−1 and iron 9 mg L−1. The photosynthetic behaviour validates the high lipid productivity under combined nutrient stress condition. Saturated fatty acid composition was increased by 38.49% under selected nutrient stress condition compared to BG11 medium. The enhanced lipid accumulation with suitable lipid profile (C16:0, C18:1, C18:2, C18:3) and biodiesel conversion of 91.54 ± 1.43% achieved in A. falcatus KJ671624 further confirm its potential as a promising feedstock for biodiesel production.