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 x 10(6) cells/mL and total fatty acid of 97.9 mg/g-DCW, enhancing the growth by 1.9-fold compared to control (9.5 x 10(6) 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 x 10(6) 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. (C) 2014 Elsevier Ltd. All rights reserved.