GROWTH AND FATTY ACID COMPOSITION OF MARINE MICROALGA NANNOCHLOROPSIS sp IN MEDIUM ENRICHED WITH MAGNESIUM

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J. Tri astuti
Lies Sriwuryandari
Ekoputro Agung Putro
T. Sembiring

Abstract

Micro-algae are to be an attractive way to produce bio-diesel due to high photosynthetic yields and lipid accumulation in cells. This high productivity combined with possibility to uptake CO2 stimulated its utilization as a biological mitigation method of CO2, at once as an alternative renewable source of energy. Growth characteristics and chemical composition of micro-algae can be altered by culture environment. Nutrient sufficiency,included magnesium element (Mg2+) is important factors on overall biochemical composition. In study, Nannochloropsis sp was cultivated in Erlenmeyer 250 ml containing 200 ml f/2 medium. There are three groups of treatment with different level
of magnesium (Mg2+), i.e. 0 (M0); 0.1mgL-1 (M1); and 1.0 mgL-1 (M2). All treatment was designed triplicate in batch system. Culture was then aerated continuously with sterile atmospheric air (1.5 L.min-1). Cells were harvested on 25th day after inoculation and analyzed. Data showed that Chlorophyll-a increased linearly with time and maximum at 18th days of growth period, i.e. 23.57; 26.44; and 27.74mgL-1, for M0; M1; and M2,respectively. Chlorophyll-a content decreased significantly when pH dropped to 5-6.Enrichment with Mg2+ increased the chlorophyll-a content 12.2-17.7%. Dry cell reached 375-400mgL-1 in all treatment. Lipid content of Nannochloropsis sp in control (M0) is 55.3%, higher than M1 and M2. Saturated fatty acid tends to increase from 80.70 (M0)
to 96.70 (M1) and 94.53% (M2). Fatty acid of M0 and M1 was composed dominantly by palmitic acid (C16:0), i.e. 49.19-70.75% total fatty acids. Meanwhile, M2 treatment was dominantly by lauric acid (C12:0), i.e. 32.98%.
Keywords: CO2 biological mitigation, chlorophyll-a, fatty acid, lipid, agnesium,
microalgae, Nannochloropsis sp, photosynthesis.

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Section
RESEARCH ARTICLES
Author Biographies

J. Tri astuti, Lembaga Ilmu Pengetahuan Indonesia

Indonesian Institute of Sciences

Lies Sriwuryandari, Lembaga Ilmu Pengetahuan Indonesia

Indonesian Institute of Sciences

Ekoputro Agung Putro, Lembaga Ilmu Pengetahuan Indonesia

Indonesian Institute of Sciences

T. Sembiring, Lembaga Ilmu Pengetahuan Indonesia

Indonesian Institute of Sciences