Strain selection of microalgae isolated from Tunisian coast: characterization of the lipid profile for potential...

Microalgae could be of importance for future biodiesel production as an alternative for a third generation of biofuels. To select the most appropriate strain for biodiesel production, three microalgae species, namely Isochrysis sp., Nannochloropsis maritima and Tetraselmis sp., isolated from Tunisian coast, were biochemically characterized. Initially, gas chromatography analysis showed that Isochrysis sp. and N. maritima contained 5- and 10-fold total fatty acids, respectively, more than Tetraselmis sp. Then, the two microalgae Isochrysis sp. and N. maritima were subject to random mutagenesis using ultraviolet-C radiation. Subsequently, a total of 18 mutants were obtained from both species. The neutral lipid evaluation on said 18 mutants allowed the retention of only 7 to further fatty acid characterization. Finally, gas chromatography revealed that the mutant 5c Isochrysis sp. was characterized by a high level of saturated fatty acids (52.3%), higher amount of monounsaturated fatty acids (29.3%), lower level of polyunsaturated fatty acids (18.4%) and a significant 1.3-fold increase in its C16-C18 content compared to the wild-type strain, which would make it an interesting candidate for biofuel production.