Abstract: A fast and easy two-step statistical optimization of cultivation condition for producing lipid by Scenedesmus obliquus was described. At first, a fractional factorial design (FFD) was used to screen signi-ficant factors from six factors (illumination, temperature, pH value, inoculation, glucose concentration and nitrogen source concentration). Then an orthogonal experiment was executed to further determine optimal conditions. According to the results, nitrogen source concentration and temperature were selected as significant factors. The optimal conditions occurred at nitrogen source concentration 6.0 mmol/L, temperature 25 ℃ and illumination 80 μmol/(m²· s), with the highest lipid productivity of 75.46 mg/(L·d).

Key words: Scenedesmus obliquus, fractional factorial design, orthogonal design, lipid productivity