The present work was oriented toward analyzing the growth and total lipid accumulation of two green microalgae, Pseudochlorococcum polymorphum UTEX 1791 and Pseudochlorococcum typicum UTEX 1792, both of which were cultured in the BG-11medium but under different sodium nitrate concentrations of 0.3, 0.5, 1.0, and 1.5 g·L−1. The results showed that the sodium nitrate concentration, ranging from 0.3 to 1.0g·L−1 was suitable for the growth of P. polymorphum UTEX 1791:its final dry biomass weight was about 3.7g·L−1. The optimum concentration of sodium nitrate for P. typicum UTEX 1792 was 1.0 g·L−1, and its final dry biomass weight reached 4.35g·L−1. The close relationship between the variation of chlorophyll a content and the accumulation of total lipid was observed from these two algal cultures. At the early growth phase, the content of chlorophyll a in all experimental groups increased sharply, while the total lipid accumulation was not significant. However, in the mid growth phase, the content of chlorophyll a increased slowly, but the total lipid content increased significantly in all experimental groups, especially in the 0.3g·L−1 of sodium nitrate group, whose total lipid content increased by 11.65%(UTEX1791) and 24.99% (UTEX 1792), the maximum total lipid content and yield were up to 26.28% (dry weight)(UTEX1791) and 44.35% (dry weight) (UTEX 1792), 0.98 g·L−1 (UTEX 1791) and 1.61 g·L−1 (UTEX 1792), respectively.% 以多形拟绿球藻(Pseudochlorococcum polymorphum UTEX 1791)和模式拟绿球藻(Pseudochlorococcum typicum UTEX 1792)为材料,采用BG-11培养基,研究其在0.3、0.5、1.0和1.5g·L−1等4个硝酸钠浓度条件下的生长和总脂含量.结果表明：适宜多形拟绿球藻生长的硝酸钠浓度范围为0.3—1.0g·L−1,其最终生物质干重在3.7g·L−1左右；模式拟绿球藻在1.0g·L−1的硝酸钠浓度条件下生长最好,可获得4.35g·L−1的生物质干重.在培养过程中两株绿藻的叶绿素a含量与总脂的含量关系密切,在培养初期各实验组叶绿素a含量增加,藻体的总脂含量增长不明显,而在培养中期藻细胞叶绿素 a的含量增长平缓,总脂含量增长较明显,其中在0.3g·L−1的硝酸钠浓度实验组总脂增长最为显著,多形拟绿球藻增长了11.65%,模式拟绿球藻增长了24.99%.两株绿藻在0.3g·L−1的低氮实验组总脂含量最高,多形拟绿球藻和模式拟绿球藻总脂分别为细胞干重的44.35%和26.28%,在此条件下两株藻的最大总脂收获量分别为0.98g·L−1和1.61g·L−1.
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