Characterization of Euglena sp. Amino Acids and Fatty Acid Methyl Ester (FAME) in Correlation to Ammonium Sulfate (NH₄)₂SO₄ Variation: Large-Scale Cultivation

Ammonium sulfate (NH₄)₂SO₄ as a source of N compounds in the growth medium of Euglena sp. has a major role in growth, vegetative cell formation, protein formation, lipid, and other organic compounds. Euglena sp. are microalgae that can grow in environments with acidic pH and high ammonia levels. In this study, variation of ammonium sulfate treatments at different concentrations includes low nitrogen level/F1 (0.5 g L-1), control (1 g L-1), and high nitrogen level/F2 (2 g L-1). This study aimed to define and quantify the amount of FAME, amino acids, growth, and biomass of Euglena sp. cultured on a large scale over a period of 16 days. FAME components were tested using Gas Chromatography Flame-Ionization Detector (GC-FID) and amino acids were characterized using Ultra Performance Liquid Chromatography (UPLC). The highest lipid content in F1 (0.209±0.0133 mg mL-1), while the highest protein content (23.1792±2.2607µg mL-1), and the highest biomass content (0.1444±0.0406 mg mL-1) found in F2. The SFA components in Euglena sp. elevated with low nitrogen treatment, with methyl arachidate (C20:0), methyl heneicosanoate (C21:0), and methyl palmitoleate (C16:1) with values of 18.76%; 13.54%; and 10.18%, respectively. The amino acid characterization generated 18 compounds, with the highest amino acid concentration of L-Arginine in the control group (15233.09 mg kg-1), and typical amino acids obtained were L-Alanine, L-Tyrosine, L-Histidine, L-Tryptophan, L-Aspartic acid, and L-Serine (VIP score>1).