Fig. 4. The effects of the reaction temperature 1, hexane solution-to-methanol ratio2 , and reaction time 3 on the transesterification of the extracted microalgae oil dissolved in hexane. 1 The experiments were performed under the following conditions: amount of oil-hexane solution, 12 mL; hexane solution-to-methanol ratio, 2:1; mixing speed, 600 rpm; reaction time, 20 min. 2 The experiments were performed under the following conditions: amount of oil-hexane solution, 12 mL; temperature, 45 C; mixing speed, 600 rpm; reaction time, 20 min. 3 The experiments were performed under the following conditions: amount of oil-hexane solution, 12 mL; hexane solution-to-methanol ratio, 6:1; temperature, 45 C; mixing speed, 600 rpm.