Regulatory effect of gibberellic acid (GA3) on the biomass productivity and some metabolites of a marine microalga, Isoc

  • PDF / 471,079 Bytes
  • 8 Pages / 595.276 x 790.866 pts Page_size
  • 103 Downloads / 144 Views

DOWNLOAD

REPORT


Regulatory effect of gibberellic acid (GA3) on the biomass productivity and some metabolites of a marine microalga, Isochrysis galbana Nasim Sadat Hosseini Madani 1 & Mehdi Shamsaie Mehrgan 1 Nima Pourang 2

&

Seyed Pezhman Hosseini Shekarabi 1

&

Received: 28 June 2020 / Revised and accepted: 30 September 2020 # Springer Nature B.V. 2020

Abstract The application of phytohormones is an effective and economical way to accelerate biomass growth and the synthesis of valuable metabolites in the microalgae industry. In this study different levels of gibberellic acid (GA3), including 0 (control), 1, 2, 4, and 6 mg L−1, were added to the growth medium of Isochrysis galbana to evaluate the growth performance, metabolites (i.e., chlorophyll a, protein, lipid, carbohydrate, and ash), and fatty acids profile, compared with the control group (0 mg L−1 GA3) during a 14-day experiment. The highest cell number (14.2 × 106 cells mL−1) and the lowest doubling time (4.31 day) were obtained in 4 mg L−1 GA3 (P < 0.05) and the highest specific growth rate was recorded in the treatments with GA3 at 2 and 4 mg L−1. The production of chlorophyll a was elevated by increasing GA3 concentration up to 4 mg L−1, while the lowest value was recorded in 6 mg L−1 GA3 (P < 0.05). The highest level of protein was measured in 1, 2, and 4 mg L−1 GA3, while the lowest value was obtained in the control group (P < 0.05). In addition, the lipid content of the microalgae treated with different GA3 concentrations was significantly increased compared with the control group. The highest polyunsaturated fatty acid (PUFA) content was achieved using GA3 at 6 mg L−1, while the highest saturated and monounsaturated fatty acids were determined in 2 mg L−1 GA3. The findings showed that GA3 at 4 mg L−1 could effectively improve the growth and biosynthesis of most metabolites in I. galbana. Keywords Haptophyta . Gibberellin . Phytohormones . Long-chain fatty acids

Introduction Recently several methods, including genetic manipulation, nutrient starvation, and other physicochemical stresses (i.e., salinity, temperature, pH, alkalinity, and irradiance), have been studied to promote the bioaccumulation of various metabolites in different microalgae species (Converti et al. 2009; Durmaz et al. 2009; Paes et al. 2016). However, some of these

* Mehdi Shamsaie Mehrgan [email protected] * Seyed Pezhman Hosseini Shekarabi [email protected] 1

Department of Fisheries, Science and Research Branch, Islamic Azad University, Tehran, Iran

2

Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

methods may not applicable in the large-scale production of microalgae or they may have unfavorable effects on the biomass production (Rawat et al. 2013; Medipally et al. 2015). Phytohormones such as auxin, gibberellic acid (GA3), cytokine, and ethylene are used to control the growth and a number of physiological activities in higher plants and microalgae (Singh et al. 2016; Parsaeimehr et a