Enhancement of microalgae growth and fatty acid content under the influence of phytohormones

The growth of Scenedesmus obliquus improved with increase in phytohormones concentrations (10−8–10−5 M). Indole-3-acetic acid (IAA) supported the maximum growth at 10−5 M with 17.7 × 106 cells/mL and total fatty acid of 97.9 mg/g-DCW, enhancing the growth by 1.9-fold compared to control (9.5 × 106 cells/mL). While 10−5 M of a newly discovered phytohormone Diethyl aminoethyl hexanoate (DAH) demonstrated a 2.5-fold higher growth with 23.5 × 106 cells/mL and a total fatty acid content of 100 mg/g-DCW. Poly-unsaturated fatty acid content increased up to 56% and 59% at 10−5 M of IAA and DAH, respectively. The highest carbohydrate content (33% and 34%) achieved at 10−8 M and 10−5 M of IAA and DAH, respectively. While, the highest protein content (34% and 35%) obtained at 10−8 M of IAA and DAH, respectively. The current investigation demonstrates that phytohormones accelerate microalgal growth and induce the quality and quantity of fatty acid content for biodiesel production.