BIODIESEL DARI LIPID MIKROALGA Thalassiosira sp. dan Chaetoceros sp. SEBAGAI SUMBER ENERGI ALTERNATIF

• Main Author: Anita, Syahfitri
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34997
• Institution: Institut Teknologi Bandung

The level of world energy consumption particularly biodiesel is increasing and predicted will continue to rise until 2035. In the other hand, raw material supplies of fossil energy are limited, so it is necessary to find a new renewable energy source. Currently, renewable energy raw materials derived from terrestrial plants. However, they are too risky when used for biodiesel source material because it will compete with food purposes. Therefore, it is necessary to find other renewable energy sources. Several studies reported that microalgae produced high fatty acid content and might become resources for biodiesel production. Microalgae are a phytoplankton that is abundant in the waters. Indonesia has oceans containing diverse types of microalgae which potential for biodiesel resources. This research aimed to see the potency of microalgae Thalassiosira sp. and Chaetoceros sp. as a source of fatty acid and biodiesel. In this research, first microalgae monoculture were activated in the Batch system to shorten adaptation period and to obtain active inoculums. The active inoculums were grown in the same system in the activation process. The observation of microalgal growth was carried out to obtain growth profile, to determine proper harvesting time and to obtain sufficient amount of biomass for the next process. Microalgal cells were harvested by the method of centrifugation, the paste were stored. After sufficient microalgae biomass was obtained, to extract lipid from cells the extraction process is carried out by the Soxhlet extraction using chloroform: methanol (1:1) as solvent. The extracted lipid was then transesterified, and biodiesel formed was qualitatively analyzed through a simple flame test. The darkness of microalgae culture showed that the cells had successfully activated and the biomass increased. The cell growth profile of both microalgae showed the phases of growth profile of common microorganisms. The optimum biomass of culture of Thalassiosira sp. was obtained at the day 10 with cell density of 8.71 × 106 cells/ml, and Chaetoceros sp. culture was at the day 9 with cell density of 8.84 × 106 cells/ml. The microalgal paste concentration Thalassiosira sp. and Chaetoceros sp obtained was 10.41 and 7.63 g/l, respectively. Lipid extraction from microalgal cells produced brown solid. It might be caused by fucoxanthin pigments that also extracted, and lipid content was dominated by saturated fatty acids. The mass of lipid obtained from Thalassiosira sp. was 2.27 g or 21.78% of the total microalgae paste, and from Chaetoceros sp. was 1.23 g or 16.20% of the total microalgae paste. Transesterification of lipid using methanol produced brown biodiesel containing fucoxanthin pigments. The mass of biodiesel obtained from Thalassiosira sp. was 1.92 g or 84.58% of total lipid and from Chaetoceros sp. was 0.88 g or 71.55% of total lipid. To see biodiesel property of qualitatively as a fuel, a simple flame test was performed. For comparison, the same test was also conducted on kerosene and biodiesel from palm oil. Simple flame test result showed that kerosene had the biggest flame. Meanwhile, biodiesel flames of Thalassiosira sp. and Chaetoceros sp. was as large as the flames of palm oil biodiesel. This indicated that biodiesel from microalgae Thalasiosira sp. and Chaetoceros sp. could be used as an alternative energy source.