Characterization of a newly isolated green microalga Scenedesmus sp. as a potential source of biodiesel

Abstract

An oil-producing microalga SP-01 belonging to the genus Scenedesmus was shown to be able to grow on a media containing 5 to 30 g L-1 NaCl. Under mixotrophic condition, the maximum cell dry weight of 3.1 g L^-1 and specific growth rate of 0.034 h^-1 were obtained at 0.5 g L^-1 NaNO₃ and 6 g L^-1 acetate. The effects of salinity on the biomass, lipid, and carotenoid productions of the alga SP-01 in mixotrophic mode were investigated. The biomass productivity increased with increasing NaNO3 concentrations, and addition of NaCl resulted in a higher biomass while NaNO₃ was present. The maximum lipid content was obtained while no NaNO₃ and NaCl was added, and the lipid content decreased with increasing NaNO₃ concentrations or addition of NaCl. The maximum lipid productivities of 67.44 to 68.44 mg L-1day^-1 were obtained while NaNO3 and NaCl were not added or while 20 g L^-1 NaCl and 0.13 g L^-1 NaNO₃ were added. The algal lipid was mainly composed of C16 and C18 fatty acids accounting for more than 90% of total fatty acids. Furthermore, lutein and astaxanthin were the main carotenoids.

Key words: Halotolerant, microalga, Scenedesmus sp., mixotrophic culture, lipid, carotenoid.