Optimizing a Solvent System for Lipid Extraction From Cyanobacteria

Abstract

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Due to higher photosynthetic efficiency, higher biomass production, rapid lipid accumulation and faster growth than other conventional crop products, cyanobacterial lipids have great potential for the production o f carbon neutral biodiesel. Biodiesel gives less harmful em issions than conventional diesel and hence the use o f biofuel is a shift toward “sustainable energy”. This study was carried out to optimize a solvent system to extract lipids from cyanobacteria. Many solvent system s, namely, n-hexane, chloroform: methanol (2:1), n-hexane: ethanol (3:2), chloroform: n-hexane (1:1), dichloromethane: methanol (1:1), n-hexane: isopropanol (1:1) and diethyl ether system s were used to extract lipids from cyanobacteria. The extracted lipid yields (g /l g o f dried biomass) o f solvent system s were 1.11, 1.61, 1.71, 2.15, 3.41, 4.33 and 1.95 wt.%, respectively. Fatty acid methyl ester (FAM E) com positions were 81.32, 78.27. 76.39, 29.01, 85.72, 92.39 and 80.09%, respectively for each solvent system. The GC-MS analysis revealed that the most abundant fatty acid types o f Microcystis were palmitic acid ( 0 6 : 0 ) and its derivatives (14-m ethyl pentadecanoic acid) which are more suitable for a quality biodiesel product. About 4.33 wt.% o f lipids and 92.39% FAME composition were obtained from the n-hexane/isopropanol solvent system . Thus, this preliminary study indicates the potential use o f cyanobacteria for biodiesel production and the optimized, n-hexane: isopropanol (1:1) solvent system found to be the most efficient when compared to the other solvent system s em ployed in the present study.