A polyphasic approach in the identification and biochemical characterization of <i>Dunaliella tertiolecta</i> with biodiesel potential from a saltern in Mauritius

Bioprospecting robust and oleaginous strain is crucial for the commercialization of microalgae-based biodiesel. In this study, a microalgal strain SCH18 was isolated from a solar saltern located in Mauritius. This isolate was identified as <i>Dunaliella tertiolecta</i> based on a polyphasic approach that combined molecular, physiological, and morphological analyses. Furthermore, the effect of different salinities on the biochemical composition and fatty acid profile of this microalga was investigated to explore its potential in producing biodiesel. Results from the growth studies showed that salinity of 1.0 M NaCl was optimal for achieving a high growth rate. Under this salt concentration, the growth rate and the doubling time were calculated as 0.39 ± 0.003 day^-1 and 1.79 ± 0.01 days, respectively. In terms of biochemical composition, a substantial amount of carbohydrate (42.02 ± 5.20%), moderate amount of protein (30.35 ± 0.18%) and a low lipid content (17.81 ± 2.4%) were obtained under optimal NaCl concentration. The fatty acid analysis indicated the presence of palmitic acid, stearic acid, palmitoleic acid, oleic acid, linoleic acid, gamma, and alpha-linolenic acids, which are suitable for biodiesel synthesis. The predicted biodiesel properties were in accordance with the standard of ASTM 6751, indicating that the microalgal isolate <i>D</i>. <i>tertiolecta</i> SCH18 is a potential candidate for use in biodiesel production.