The new Arctic Chlorella species: growth and lipid contents

Abstract

Microalgae are considered as promising sources for biofuel production. In cold temperature, it is difficult to maintain proper culture condition for outdoor mass cultivation. Most microalgae inhabited in the polar region are able to grow at extreme cold temperature. Two Chlorella species, ArF0004 and ArF0006 were isolated from the Arctic sea ice and grown at various culture temperatures of 4, 8, 12, and 20℃. The maximal cell densities of ArF0004 and ArF0006 in Bold's Basal Medium (BBM) were 1.4×107 cells/ml at 8℃ and 8.3×106 cells/ml at 20℃, respectively. The formation of lipid body of two Chlorella species were visualized by Nile red staining method and exhibited yellow-gold at 488 nm fluorescence. The fatty acid methyl esters (FAMEs) were analyzed using gas chromatography. ArF0004 and ArF0006 showed similar fatty acid contents, which were dominated by cis-10-heptadecenoic acid methyl ester (C17:1), 5,8,11-heptadecatrienoic acid methyl ester (C17:3) and α-linolenic acid methyl ester (C18:3). ArF0004 and ArF0006 also presented mainly α-linolenic acid methyl ester content (~27.6%) recommended FAMEs for good biodiesel properties. The two Arctic microalgae could grow at a wide range of temperatures and produce lipids at low temperature. Thus, we could expect that two Arctic Chlorella species may be suitable candidates for biofuel production.