OPTIMIZATION OF SALINITY AND C:N RATIO ON LIPID PRODUCTION FROM SCENEDESMUS SP. IN TWO-STEP CULTIVATION WITH RESPONSE SURFACE METHODOLOGY (RSM) APPROACH

• Main Author: Helena Putri Hermansyah, Happy
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83120
• Institution: Institut Teknologi Bandung

Interest in the utilization of microalgae as a source of PUFAs has increased, especially in the field of nutraceuticals. Scenedesmus sp. is one of the microalgae used in PUFA production due to its lipid accumulation which reaches up to 18- 50% (w/b) dry weight. In this study, one-step and two-step cultivation of microalgae was conducted. In the first stage, biomass multiplication of Scenedesmus sp. was carried out on NPK Growmore media (N:P:K = 32:10:10) 1 g/L. Stage one cultivation was conducted at a working volume of 800 mL for 72 hours with an inoculum volume of 10% (v/v) with a log cell density of 6.2 cells/mL. Stage two cultivation was conducted photoheterotrophically at a working volume of 800 mL for 120 hours with an inoculum volume of 10% (v/v) with a log cell density of 7 cells/mL. In the second stage of cultivation, the salinity and C:N ratio variations used were 0.5%, 1%, 2% (% w/v), and 3, 35, and 70 respectively. The purpose of this study is to determine the optimal salinity variation and C:N ratio and to determine the stochastic model for the lipid content response of Scenedesmus sp. growth with two-step cultivation. In one-step cultivation, the specific growth rate (µ) (h-1) of Scenedesmus sp. was 0.0336 h-1 with doubling time of 20.61 hours. In this study, the analysis and optimization method of two-step cultivation response was carried out with Response Surface Methodology (RSM) and response optimizer. The addition of salinity and C:N ratio in the range of 1%-1.75% (w/v) and 20-60 were positively correlated to the maximum biomass response and the optimal lipid content based on the response optimizer was 1.55 g/L and 66.97% (w/v) at 1.26% (w/v) salinity and 38.69 C:N ratio. The response stochastic model of lipid content obtained is; lipid content (%) = -33.9 + 110.3 A + 1.546 B - 0.098 AB - 41.76 A2 -0.0179B2, where A is salinity (%) and B is C:N ratio