Philippine E-Journals

INFLUENCE OF SALINITY IN FATTY ACID PRODUCTION OF Dunaliella sp. AS FEEDSTOCK FOR BIODIESEL

John Erasmos Marie P Talosig | Kia Dyan Louren I Serrano | Armin S Coronado

Discipline: natural sciences (non-specific), production and manufacturing engineering

 

Abstract:

Dunaliella sp. is a unicellular, eukaryotic, photosynthetic, and halophilic microalga. It is one of the prospective microalgae being utilized for its significant amounts of valuable chemical matters such as carotenoid, glycerol, and lipids. Dunaliella has a potential as feedstock in the production of biodiesel but there is only limited data and information available as most studies are focused to commercial production of highvalue products such as beta-carotene. Therefore, it is necessary to evaluate the culture condition of Dunaliella sp. that promotes higher lipid production. Dunaliella sp. was cultivated at varying salinity conditions (45 g/L, 50 g/L, 55 g/L, 60 g/L, 65 g/L, and 70 g/L) using Conway medium (CM). Algal biomass for each culture condition was harvested at the end of logarithmic phase [Period 1 (P1) or day 10] and onset of decline phase [Period 2 (P2) or day 13] of cultivation. At P1, the highest biomass was obtained from CM50 (1.152 ± 0.120 g/L) while CM45 (2.109 ± 0.168 g/L) for P2. Lipid/oil was extracted from algal biomass cultivated at different salinity concentrations by Bligh and Dyer method using solvent mixture of chloroform and methanol (1:2). CM60 has the highest oil yield in both periods, P1 (1.494 ± 0.190 %) and in P2 (1.636 ± 0.173%). Lipid/Oil from top three (3) oil producing treatments were transesterified to produce the Fatty Acid Methyl Ester (FAME) and subjected to Gas Chromatography - Mass Spectrometry (GC-MS) for fatty acid composition analysis. There are 22 fatty acids identified in P1 while 28 fatty acids in P2. However, only 11 fatty acids identified in all treatments were desirable for biodiesel production namely myristic acid, methyl pentadecanoate acid, palmitic acid, stearic acid, palmitoleic acid, methyl palmitoleate acid, valeric acid, elaidic acid, linoleic acid, oleic acid, and petroselinic acid. Among algal cultures, only CM55 exhibited ideal mix ratio of fatty acid’s palmitoleic (16:1), oleic acid (18:1), and myristic acid (14:0) with good biodiesel property (5:3:1). Therefore, Dunaliella sp. has a potential as feedstock for biodiesel production with decent amount biomass and lipid/oil using Conway medium that can also exhibit good fuel properties when cultivated at 55g/L of salinity.