AUTHOR=Do Jeong-Mi , Yeo Hee-Tae , Suh Ho Seong , Yoon Ho-Sung 

TITLE=Effect of salt stress on the biomass productivity and potential bioenergy feedstock of Graesiella emersonii KNUA204 isolated from Ulleungdo Island, South Korea

JOURNAL=Frontiers in Energy Research

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2023.1056835

DOI=10.3389/fenrg.2023.1056835

ISSN=2296-598X

ABSTRACT=<p>Microalgae are versatile, profitable, and promising sources of bioenergy and high-value products, having various applications in the biotechnology industry. Herein, <italic>G. emersonii</italic> KNUA204 was isolated from Ulleungdo Island, South Korea, and exposed to stressors, i.e., MgCl<sub>2</sub> (75 and 150 mM) and NaCl (200 and 400 mM), to investigate improvement in its biomass productivity and feasibility of the application of biomass. Treatment with mild MgCl<sub>2</sub> (75 mM) afforded the highest specific growth rate (μ = 0.13 d<sup>−1</sup>), dry cell weight (3 g L<sup>−1</sup>), and total carbohydrate content (29.87%). Although all salt treatments decreased chlorophyll and carotenoid contents, treatment with high NaCl concentration (400 mM) afforded the highest zeaxanthin content (0.3 mg g<sup>−1</sup>). The proximate and ultimate analyses of biomass following treatment with 150 mM MgCl<sub>2</sub> revealed 93.85% volatile matter and 22.55 MJ kg<sup>−1</sup> calorific value, respectively, indicating that <italic>Graesiella emersonii</italic> KNUA204 can be potentially used as bioenergy feedstock. The biodiesel quality was established based on the fatty acid methyl ester profiles, and MgCl<sub>2</sub> treatment increased the cetane number more than the control. Therefore, the treatment of <italic>G. emersonii</italic> KNUA204 with MgCl<sub>2</sub> during cultivation could provide a microalgae-based bioenergy feedstock with high productivity.</p>