STRATEGY FOR ENHANCING LIPID PRODUCTION OF CHLORELLA VULGARIS THROUGH SINGLE AND MULTIPLE-STRESS ON COMMERCIAL FERTILIZER MEDIUM

• Main Author: Azahra, Siti
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/77135
• Institution: Institut Teknologi Bandung

Lipid microalgae is an alternative raw material for products in various industrial sectors such as energy, food, feed, and health. The productivity of lipid microalgae depends on cultivation conditions. One of these conditions is cultivation under salinity and nutrient stress. Several studies have shown that salinity stress leads to osmotic and oxidative stress, resulting in higher lipid accumulation (21.40% w/w - 56.42% w/w). Therefore, strategies to enhance lipid production in microalgae can be carried out through salinity stress by cultivating in a single stage or continuing with the addition of nutrient stress in the second stage. This research aims to: (i) Determine the optimum NaCl concentration for lipid productivity and total lipid content of Chlorella vulgaris in single-stage and two-stage cultivation; (ii) Determine the optimum harvest phase for lipid productivity and total lipid content of Chlorella vulgaris; and (iii) Determine the optimum cultivation strategy based on lipid productivity and total lipid content of Chlorella vulgaris. In this study, C. vulgaris was cultivated at an aeration rate of 1.5 vvm and a photoperiod of 16:8 (light: dark). Salinity stress was induced by adding NaCl (5 g/L or 10 g/L) to the Nutri-comp D fertilizer medium (0.72 g/L) and SP-36 fertilizer (35 mg/L). The use of SP-36 fertilizer created a nutrient stress environment. Harvest phases of C. vulgaris were at the end of exponential growth, mid-stationary phase, and end-stationary phase. There was an influence of NaCl concentration, harvest phase, and cultivation strategy on productivity and total lipid content (p-value < 0,05). Optimum total lipid (27.7 g/L) and optimum productivity (13.5 g/L/day) were achieved under multiple-stress conditions, harvested at the end of the exponential growth phase of the first-stage cultivation with a concentration of 5g/L NaCl. Multiple-stress total lipid (3.3 g/L - 27.7 g/L) was higher than single stress (0.9 g/L - 10 g/L), indicating an interaction between salinity and nutrient stress (p-value < 0,05). Therefore, multiple-stress conditions are suitable as a strategy to enhance lipid production in Chlorella vulgaris.