초록
<P><B>Abstract</B></P><P>Cyanobacteria were cultivated in laboratory to determine CO<SUB>2</SUB> fixation rates and for extraction of lipids. The experiments were carried out in 4 phases, namely: flask cultivation of <I>Synechocystis aquatilis</I> TISTR8612 (<I>S. aquatilis</I>) to determine their optimal growth conditions; batch experiments in airlift photo-bioreactor (PBR) for estimation of CO<SUB>2</SUB> fixation rates; continuous experiments in airlift PBR to evaluate biomass production and CO<SUB>2</SUB> fixation rates; and development of appropriate method for lipid extraction from <I>S. aquatilis</I>.</P><P>Investigations revealed that the optimum conditions for cultivating <I>S. aquatilis</I> were: pH 8, temperature of 30 °C, and illuminance of 4 klx. Batch experiments conducted at 5% inlet CO<SUB>2</SUB> yielded maximum CO<SUB>2</SUB> fixation rate at space velocity of 14 min<SUP>−1</SUP>. On the other hand, continuous experiments in airlift PBR revealed optimum dilution rate of 0.012 d<SUP>−1</SUP> with maximum biomass production rate of 932 mg L<SUP>−1</SUP> d<SUP>−1</SUP>. Inlet CO<SUB>2</SUB> concentration of 8% was found to be most suitable to yield CO<SUB>2</SUB> fixation rate of 5.3 g L<SUP>−1</SUP> d<SUP>−1</SUP>. Lipid extraction procedure comprising of sonication and solvent extraction (chloroform:methanol as 1:1 by volume) resulted in highest lipid yield of 18.58%. The extracted fatty acids were mostly composed of polyunsaturated fatty acids such as linoleic and α-linolenic acid.</P> <P><B>Highlights</B></P><P>► Synechocystis aquatilis was cultivated in laboratory for extraction of lipids. ► Optimum growth conditions for S. aquatilis were found as pH 8, 30 °C, and 4 klx. ► Continuous experiments were carried out in airlift photo bioreactor. ► Maximum biomass production rate of 932 mg L<SUP>−1</SUP> d<SUP>−1</SUP> was obtained. ► Extracted lipids contained saturated and polyunsaturated fatty acids.</P>