Isolation of Microalgae from Mediterranean Seawater and Production of Lipids in the Cultivated Species

Abstract

Isolation and identification of novel microalgae strains with high lipid productivity is one of the most important research topics to have emerged recently. However, practical production processes will probably require the use of local strains adapted to commanding climatic conditions. The present manuscript describes the isolation of 96 microalgae strains from seawater located in Bay M'diq, Morocco. Four strains were identified using the 18S rDNA and morphological identification through microscopic examination. The biomass and lipid productivity were compared and showed good results for Nannochloris sp., (15.93 mg/L/day). The lipid content in the four species, namely Nannochloropsis gaditana, Nannochloris sp., Phaedactylum tricornutum and Tetraselmis suecica, was carried out by high performance liquid chromatography coupled to mass spectrometry (HPLC-MS )highlighting the identification of up to 77 compounds.

Keywords: HPLC-MS; identification; isolation; lipid productivity; microalgae.

Figure 1

Distribution map of sampling points in M’diq Bay, Morocco.

Figure 2

Method of cell isolation with (A) successive dilution, and (B) inoculation on an agar plate.

Figure 3

Strains curves for isolated microalgae using successive dilution, (A) inoculating on an agar plate, (B) in F/2 with or without silicate and (C) incubation at 20 °C and 26 °C.

Figure 4

Light microscopic observation of isolated microalgae: (A) Nannochloropsis gaditana, (B) Phaeodactylum tricornutum, (C) Nannochloris sp., and (D) Tetraselmis suecica.

Figure 5

Molecular identification of selected microalgae. 1 to 7: number of strains. (a,b): annealing T° of 56 °C. (c): annealing T° of 60 °C.

Figure 6

Base peak chromatograms of lipids extract of four isolated microalgae. (A) N. gaditana; (B); T. suecica; (C) P. tricornutum; (D) Nannochloris sp. For experimental conditions, see the text. For peak identification, see Table 4.