Selection of elite microalgae for biodiesel production in tropical conditions using a standardized platform

•Thermotolerant and high lipid content microalgae were isolated from tropical Taiwan.•A platform was set up to evaluate biodiesel production-related traits of microalgae.•Desmodesmus sp. F2 is one of the best microalgae for biodiesel production in tropical areas.•The proposed procedures serve as standard protocols to assess microalgal potentials. Four thermotolerant microalgae were isolated from tropical Taiwan and classified as members of Desmodesmus based on morphological and molecular studies. A platform was established to evaluate their biodiesel production-related traits, including thermotolerance, lipid productivity, lipid oxidative stability and auto-sedimentation. The findings demonstrated thermotolerance of all four species was at the same level, as all could live at 45°C for 24h and 50°C for 8h with mortality rates below 5% of cells. The lipid productivity of Desmodesmus sp. F2 reached 113mg/L/d. Its saturated and monounsaturated fatty acids accounted for 75% of the FAMEs, and it required only 3.1h to achieve 85% sedimentation. Comparing these traits to those of the other three Desmodesmus and microalgae in the literature, Desmodesmus sp. F2 is one of the best candidates for biodiesel production in tropical and subtropical areas. This platform effectively assessed traits of microalgae related to biodiesel production.