PRODUKSI BIOMASSA DAN LIPID MIKROALGA CHLORELLA VULGARIS MELALUI KULTIVASI MENGGUNAKAN FOTOBIOREAKTOR DENGAN PENAMBAHAN CEKAMAN SALINITAS

• Main Author: Mabrur, Hafidz
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/84664
• Institution: Institut Teknologi Bandung

The growth of microalgae is influenced by several external factors derived from the environment where the microalgae grow, one of which is salinity. Salinity refers to the level of salt concentration in water, which is a major trigger for stress responses. Several studies show that when microalgae experience stress due to changes in salinity, their growth is inhibited, while lipid accumulation tends to increase (21.4% - 56.42% w/w). Microalgae maintain internal osmotic balance with the environment by adjusting the concentration of dissolved compounds within the cells to avoid excessive dehydration or swelling. Cultivation in a closed system using a photobioreactor allows for better control over environmental conditions, has a lower risk of contamination, and has higher productivity or yield. Biomass of the microalga Chlorella vulgaris was grown under stress conditions with salinity variations of 2.5% and 5% (w/v) NaCl at a 50 L scale using a photobioreactor. The effect of salinity on biomass growth and lipid accumulation in microalgae was analyzed based on growth kinetics parameters such as specific growth rate (day-1) and doubling time (days), biomass productivity, lipid fraction, lipid yield, and lipid productivity. One-way ANOVA statistical tests showed that NaCl concentration significantly affected biomass and lipid yield, and there was an interaction between the two (p-value < 0.05). Based on the research results, the most optimal growth conditions were obtained by adding 2.5% (w/v) NaCl, which had a specific growth rate of 0.48 ± 0.24 /day and a doubling time of 1.65 ± 0.82 days, with the highest dry cell weight of 0.0701 g/L, and the highest biomass productivity of 7.790 ± 0.039 mg/L/day. The highest lipid content (36.4% w/w) and lipid yield (0.364 g/L) were obtained with the addition of 5% (w/v) NaCl, which also had the highest lipid productivity (2.421 ± 0.029 mg/L/day). This study concludes that cultivating Chlorella vulgaris on a 50 L scale using a photobioreactor with the addition of 2.5% (w/v) NaCl resulted in the highest biomass and is the optimal concentration for growth, while the addition of 5% (w/v) NaCl resulted in the highest lipid content