Growth performance and lipid profiles of some tropical microalgae: An assessment of their potential as biofuel source

Abstract

Investigating the potential of using microalgae biomass as an environmentally acceptable biofuel feedstock in an effort to address the current dilemma of finding a sustainable alternative source of biofuel has been the main focus of many studies for the past few decades. In this context, five commercial species of tropical microalgae Tetraselmis tetrahele, Navicula ramosissima, Chaetoceros calcitrans, Thalassiosira sp., and Skeletonema tropicum were studied to evaluate their suitability as possible biofuel source. The parameters examined were ease of culture, growth performance, dry biomass yield, total lipid content, and fatty acids methyl esters (FAMEs) profiles. The diatom C. calcitrans grew the fastest among the five microalgae species, reaching a maximum cell density of 2,518,800 cells/mL, followed by the green microalgae T. tetrahele at cell density of 1,414,800 cells/mL. Biomass yields were highest in T. tetrahele (1.82 g/L) and N. ramosissima (1.28 g/L). Highest total lipid (38.32% DW) was obtained by N. ramosissima followed by T. tetrahele (23.15% DW). SFA is predominantly highest in S. tropicum, MUFA is highest in Thalassiosira sp. while PUFA is highest in N. ramosissima. Among the five microalgae evaluated, the green microalgae T.tetrahele and the diatom N. ramosissima where chosen as the best candidates for biofuel production because they produced the highest biomass yield (1.82 g/L DW and 1.28 g/L DW), lipid yield (23.15% DW and 38.32% DW), desired fatty acid profile, with adequate amounts of MUFA (46.15 %TFA and 45.08% TFA) that can potentially produce biodiesel that meets the established biodiesel standards.