Biofuels from microalgae have received great interests as one of potential solutions to mitigate climate changes and replace fossil fuels. However, the production cost of microalgal biofuel is not cost-competitive to fossil fuels yet. One way to improve economic feasibility of algal biofuels is utilizing marine resources. Photobioreactors (PBRs) with Selectively-permeable membranes (SPMs) could produce microalgae with nutrients in seawater and improve economic feasibility and sustainability. In this study, the effects of nutrient supply rates and temperature on fatty acid productivity of Tetraselmis sp. MBEyh01L in SPM-PBRs were investigated. The results showed that temperature affected both biomass productivity and fatty acid content whereas nutrient supply rate affected biomass productivity only. As nutrient supply rate was growth limiting factor of the current SPM-PBRs, increasing it would improve fatty acid productivity and further improve economic feasibility of algal biofuels.