OPTIMIZATION OF THE C:N RATIO AND INOCULUM DENSITY ON LIPID PRODUCTION FROM SCENEDESMUS SP. THROUGH TWO STEP CULTIVATION USING RESPONSE SURFACE METHODOLOGY (RSM)

• Main Author: Queeny Mirabel Gunawan, Felicia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83072
• Institution: Institut Teknologi Bandung

Lipid production in microalgae can be influenced by the C :N ratio, inoculum density, and salinity stress. To enhance lipid production, a two-stage cultivation system can be applied. The first stage of cultivation is conducted to produce biomass. In the second stage, cultivation is directed towards lipid production by adding environmental and nutritional stressors. In this study, the microalga Scenedesmus sp. was cultivated in two stages, with the first stage being photoautotrophic and the second stage being photoheterotrophic. In the second stage of cultivation, salinity stress was applied by adding 10 g/L NaCl, and variations in the C:N ratio and inoculum density were implemented to determine the optimal conditions for lipid production. The maximum lipid content and dry biomass weight under optimal conditions will be determined using a stochastic model prediction based on RSM and response optimizer. The C:N ratio variations were achieved by adding glucose at appropriate concentrations to achieve C:N ratios of 3, 35, and 70 while keeping the nitrogen concentration constant. Inoculum density variations used were Log 6.5, 7, and 7.5 cells/mL in the stationary phase. This study found that the maximum lipid content and dry biomass weight were directly proportional to the C:N ratio and inoculum density. The results of this study predicted that a C:N ratio of 36.5 and an inoculum density of Log 6.94 cells/mL would result in optimal responses for maximum lipid content and dry biomass weight, which are 71.98 (%(w/w)) and 1.615 (g/L), respectively