Li Yanqun, Horsman Mark, Wang Bei, Wu Nan, Lan Christopher Q
Department of Chemical Engineering, University of Ottawa, 161 Louis Pasteur St., Ottawa, Ontario, K1N 6N5, Canada.
Appl Microbiol Biotechnol. 2008 Dec;81(4):629-36. doi: 10.1007/s00253-008-1681-1. Epub 2008 Sep 16.
Microalgal lipids are the oils of future for sustainable biodiesel production. However, relatively high production costs due to low lipid productivity have been one of the major obstacles impeding their commercial production. We studied the effects of nitrogen sources and their concentrations on cell growth and lipid accumulation of Neochloris oleoabundans, one of the most promising oil-rich microalgal species. While the highest lipid cell content of 0.40 g/g was obtained at the lowest sodium nitrate concentration (3 mM), a remarkable lipid productivity of 0.133 g l(-1) day(-1) was achieved at 5 mM with a lipid cell content of 0.34 g/g and a biomass productivity of 0.40 g l(-1) day(-1). The highest biomass productivity was obtained at 10 mM sodium nitrate, with a biomass concentration of 3.2 g/l and a biomass productivity of 0.63 g l(-1) day(-1). It was observed that cell growth continued after the exhaustion of external nitrogen pool, hypothetically supported by the consumption of intracellular nitrogen pools such as chlorophyll molecules. The relationship among nitrate depletion, cell growth, lipid cell content, and cell chlorophyll content are discussed.
微藻脂质是可持续生物柴油生产的未来用油。然而，由于脂质生产率低导致生产成本相对较高，一直是阻碍其商业化生产的主要障碍之一。我们研究了氮源及其浓度对富油微藻新绿藻（Neochloris oleoabundans）细胞生长和脂质积累的影响，新绿藻是最有前景的富油微藻物种之一。虽然在最低硝酸钠浓度（3 mM）下获得了最高脂质细胞含量0.40 g/g，但在5 mM时实现了显著的脂质生产率0.133 g l(-1) 天(-1)，脂质细胞含量为0.34 g/g，生物质生产率为0.40 g l(-1) 天(-1)。在10 mM硝酸钠时获得了最高生物质生产率，生物质浓度为3.2 g/l，生物质生产率为0.63 g l(-1) 天(-1)。观察到外部氮库耗尽后细胞仍继续生长，推测这是由细胞内氮库（如叶绿素分子）的消耗所支持。讨论了硝酸盐耗尽、细胞生长、脂质细胞含量和细胞叶绿素含量之间的关系。
