POTENSI PENGGUNAAN PUPUK KOMERSIL SEBAGAI MEDIUM PERTUMBUHAN MIKROALGA UNTUK PRODUKSI BIODIESEL

• Main Author: Purbojo, Saskia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/55317
• Institution: Institut Teknologi Bandung

The bottleneck of microalgae-based biodiesel production is due to its high production cost. Thus, an alternative low-cost medium is highly needed. A growth medium is expected to attain high biomass, high lipid content, and a suitable fatty acid profile for biodiesel production. NutricombD fertilizer contains nutrients that have the potential to fulfill microalgae nutrition requirements. It also has a relatively lower price compared to synthetic mediums, such as Bold’s Basal Medium (BBM). The objectives of this study were to select NutricombD fertilizer media for the cultivation of C.vulgaris and C.pyrenoidosa, and to produce C.vulgaris and C.pyrenoidosa biomass with the selected growth media. Medium selection is obtained by comparing the growth of C.vulgaris and C.pyrenoidosa in BBM, NutricombD fertilizer medium, and NutricombD + BBM, which all have the same phosphate concentration. The cultivation was held for 7-10 days (Volume 1L; pH 7, 25°C, light intensity 80 ?mol m?2 s?1; 16L:8D; aeration of 3L/min) and enumerated using the direct counting method. The growth rate of C.vulgaris and C.pyrenoidosa in each media was statistically tested using one-way ANOVA (?= 0,05), and resulting in no significant difference (P>0.05). This shows that NutricombD fertilizer medium could be utilized to cultivate C.vulgaris and C.pyrenoidosa, obtaining a growth rate of 0.43 ± 0.04 days- 1 and 0.56 ± 0.14 days-1; and generation time of 1.59 ± 0.17 days and 1.24 ± 0.32 days respectively. To determine the total lipid and fatty acid profile of each species, the cultivation was carried on a 5L scale (pH 7, 25°C, light intensity 80 ?mol m?2 s?1; 16L:8D; aeration 3L/min; initial cell density of 3 x 107 cell/L). The cells were harvested through centrifugation (3146 g) and dried using a convection oven (70°C, 24 h). To obtain the lipid content, the Soxhlet extraction method was performed, using hexane as the solvent. The total lipid content of C.vulgaris is 5.14±0.00 % (w/w), and C.pyrenoidosa 2.38±0.00 % (w/w). The lipids were transesterified using methanol and NaOH (molar ratio of 5:1) as the reactant, then analyzed using GC-FID (DB FastFAME Column) to obtain the fatty acid profile. The biodiesel with a suitable property has a fatty acid ratio of palmitoleic acid (C16:1), oleic acid (C18:1), and myristic acid (C14:0) 5:4:1, however, C.vulgaris has a ratio of 5: 45.24: 3.48, and C.pyrenoidosa 5: 77.93: 3.95. The SFA, PUFA and MUFA content in C.vulgaris is 35.34±0.00%, 39.61±0.00% and 25.06±0.00% (w/w) respectively, and in C.pyrenoidosa 43.30± 0.01%, 27.64± 0.03 %, and 29.07± 0.00 % (w/w) subsequently. The cultivation of C.vulgaris in NutricompD fertilizer medium obtained a higher total lipid content and a more similar fatty acid profile to the ideal biodiesel, compared to C.pyrenoidosa.