#TITLE_ALTERNATIVE#

• Main Author: CENDARA PURBA (NIM : 11213034), CHRISYELLA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26277
• Institution: Institut Teknologi Bandung

Biomass-based energy is an alternative energy to overcome the potency of energy crisis from fossil fuel and the environmental health threats that has been discussed by researchers and global industries nowadays. Microalgae is one of the biomass stocks that can be utilized as raw material for various biomass-based fuels production. One of them is Botryococcus braunii. B. braunii is considered potential as raw material for biodiesel production because it contains lipid up to 75% dry weight. Optimization of B. braunii cultivation needs to be done to achieve high productivity. Reviewing the amount of nutrition given can be the way. Phosphorus is one of the important macronutrients in the normal growth and development of microalgae cells. The aim of this research was to determine the effect of phosphorus concentration on growth kinetics, chlorophyll and carotenoid concentration, total lipid, fatty acid composition, and lipid productivity of B. braunii. Variations of phosphorus concentration used in this research were 4 ppm, 14 ppm (control), 44 ppm, 94 ppm, and 164 ppm with 5 repetitions for each treatment. The culture was cultivated on a modified CHU-13 medium with an airflow rate of 1.5 L/minute, pH 6-9, irradiation with 5,200 lux fluorescent lamps for 16 hours of light and 8 hours of darkness, and temperature of 25°C. The highest specific growth rate (μ) was obtained by the culture with phosphorus 4 ppm (0.164 ± 0.010 g cells/day) and the lowest specific growth rate was obtained by the culture with phosphorus 94 ppm (0.109 ± 0.021 g cells/day), while μcontrol = 0.159 ± 0.019 g cells/day. The fastest doubling time (dt) was obtained by the culture with phosphorus 164 ppm (5.226 ± 0.404 days) and the latest doubling time was obtained by the culture with phosphorus 94 ppm (7.572 ± 1.260 days), while dtcontrol = 6.389 ± 0.509 days. The highest chlorophyll concentration at the end of the cultivation was obtained by the culture with phosphorus 4 ppm (39.030 ± 1.608 μg/mL) and the lowest chlorophyll concentration at the end of the cultivation was obtained by the culture with phosphorus 44 ppm (30.606 ± 2.173 μg/mL), while the chlorophyll concentration of control was 35.573 ± 4.252 μg/mL. The highest carotenoid concentration at the end of the cultivation was obtained by the control (7.347 ± 0.590 μg / mL) and the lowest carotenoid concentration at the end of the cultivation was obtained by the culture with phosphorus 164 ppm (5.847 ± 0.201 μg/mL). The highest total lipid was obtained by the culture with phosphorus 94 ppm (9.14 ± 0.74%) and the lowest total lipid was obtained by the control (3.23 ± 0.55%). The highest lipid productivity was obtained by the culture with phosphorus 94 ppm (7.7 mg/L.day) and the lowest lipid produvtivity was obtained by control (2.22 mg/L.day). The suitable fatty acid composition for biodiesel is palmitic acid where the highest content of palmitic acid (40.9%) was obtained by the culture with phosphorus 44 ppm. The lipid productivity (6.98 mg/L.day) of culture with phosphorus 44 ppm was lower than the culture with phosphorus 94 ppm but had a much higher palmitic acid composition than other treatments, so this treatment was optimal for lipid production as the source of biodiesel.