Lipid accumulation of Chlorella pyrenoidosa under mixotrophic culture using sodium acetate
LIU Li-jun, ZHAO Yuan, ZHANG Heng-feng, WANG Xiao-yu, LIANG Wen-yan
Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
The neutral lipid (NL) accumulation of Chlorella pyrenoidosa during the mixotrophic growth was studied by using sodium acetate as the organic carbon source and Nile-Red three dimensional fluorescence-regional volume integration to determine the NL content. The differences of biomass productivity, total lipid productivity, and fatty acids of lipids between mixotrophic and autotrophic culture were also investigated. The results showed that C. pyrenoidosa entered the logarithmic growth phase immediately and grew fast after sodium acetate adding, with the NL accumulation simultaneously being triggered. The concentration of 5g/L sodium acetate could not only promote the microalgal growth and the continuous NL accumulation, but also avoid the environmental stress caused by the excessive organic carbon to algae. After 12-day cultivation, the NL content per cell, biomass production, and total lipid productivity were 4.5, 2.1, and 3.1times those of the autotrophic control samples, respectively. Under the dosage of 5g/L sodium acetate, the fatty acids of lipid mainly consisted of saturated fatty acid C16:0 (22.42%) and unsaturated fatty acids C18:1 (31.58%) and C18:2 (10.89%).
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