*Corresponding author:Ines Dahmen Ben Moussa, Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax. Sidi Mansour Road Km 6, PO Box «1177», 3018 Sfax, Tunisia, North Africa
Received: September 16, 2018; Published: October 01, 2018
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Identification of cost-effective methods of cell lysis and lipid extraction from microalgae represent a critical step in the determination of promising biodiesel-producing species. Several cell disruption methods were tested in the microalgae Amphora subtropica, Tetraselmis marina, Picochlorum sp. and Dunaliella sp. Among the methods tested, enhanced lipid extraction was achieved through microwave for Amphora biomass and osmotic shock for Tetraselmis, Picochlorum, and Dunaliella biomass. The Cequier-Sanchez method rendered the highest TL content in Amphora subtropica and Picochlorum sp. while Bligh and dyer method gave the highest TL content in Tetraselmis marina and Dunaliella sp. The treatment of microalgae with 5 days of UV-B stress led to a carotenoid and lipid content increase of 44, 159, 116 and 150%, respectively, and of 56, 84, 111 and 80%, respectively, but with a reduction of the total chlorophyll content (30, 43, 24 and 34%, respectively). Furthermore, a significant increase in malondialdehyde level and superoxide dismutase, catalase and glutathione peroxidase activities toward the control was recorded in response to UV stress. Overall results indicate that treatment of Amphora, Tetraselmis, Picochlorum and Dunaliella with UV-B radiation can further increase the total lipid production, due to its high percentage of SFA and MUFA can be potentially utilized for biodiesel production.
Abbreviations: AOS: Active Oxygen Species; BD: Bligh and Dyer Method; Car: Carotenoids; CAT: Catalase; Chl: Chlorophyll; DT: Direct Trans-Esterification; FA: Fatty Acid; FAME: Fatty Acid Methyl Ester; GPx: Glutathione Peroxidase; MDA: Malondialdehyde; MUFA: Monounsaturated Fatty Acids; NBT: Nitro Blue Tetrazolium; PUFA: Polyunsaturated Fatty Acids; SFA: Saturated Fatty Acids; SOD: Superoxide-Dismutase; TL: Total Lipid; UV: Ultraviolet Radiation