Optimizing a Solvent System for Lipid Extraction From Cyanobacteria

Abstract

AttachedDue 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.