Oil Extraction of Skeletonema costatum Microalgae with the Assistance of Ultrasonic Waves

In the current conditions, the amount of petroleum is running low, so that new alternative energy is needed to support the availability of fuel oil in Indonesia. One such alternative energy is biodiesel, which is liquid fuel for diesel motors from plants or animals. Making this biodiesel needs raw materials in the form of oil. The oil used in this study is the Skeletonema costatum microalgae oil available in Jepara. Oil extraction is carried out utilizing dried microalgae then extracted with the help of ultrasonic waves. The extraction temperature used was 50, 60, 70, 80 ° C for 60, 120, 180 minutes and using hexane solvents. The results showed that the longer the extraction time according to the contraction temperature which was close to the boiling point of hexane showed an increase in the amount of microalgae oil produced. The extracted microalgae oil yield obtained optimally at 70oC for 180 minutes was 18.44%. The dominant microalgae oil content is palmitic acid as much as 74.48%, followed by oleic acid as much as 7.21%.