Genetic identification of new microalgal species from Epe Lagoon of West Africa accumulating high lipids

The green microalgal strains are favorable alternatives for producing biodiesel. In spite of the worldwide awareness on microalgae-derived oil to potentially replace the conventional fossil fuel, information on potential microalgal strains from Nigerian lagoons is scarce. In view of this, environmental samples were collected from the Epe Lagoon, Nigeria to assess the biodiversity of microalgae and identify robust strains for biodiesel production. The field samples were collected and genomic DNA was isolated from the monoclonal cultures. Microalgal species were identified based on the PCR amplified DNA sequences of 18S ribosomal DNA. The sequences of PCR products from the unknown samples were compared with the DNA database. Using the phylogenetic maximum-likelihood trees, the green algal strains Desmodesmus sp., Desmodesmus costato-granulatus, Tetradesmus sp. and Chlorella sp. were identified, while two strains belonging to the Chlorococcaceae and Family Selenastraceae need further validation. Microalgal species morphology was validated using electron microscopy. Lipid analysis was carried out using Fatty Acid Methyl Ester (FAMEs) analysis, Gas Chromatography and Mass Spectrometry (GC-MS). The strain of the Family Selenastraceae produced the maximum amount of poly-unsaturated fatty acids (56%), which has potential for food processing and other bio-based products; while Tetradesmus sp. with 35.16 mg (FAMEs per gram of dry cell weight) had a balanced lipid composition (44% saturated fatty acid, 39% mono-unsaturated fatty acid, 15% poly-unsaturated fatty acids) making it a good candidate for exploitation as a biodiesel feedstock.