不同培养模式下魏氏真眼点藻生长和产油特性的研究

为了解魏氏真眼点藻(Eustigmatos vischeri Hibberd)的生物学特性,探究"批量法"、"两步法"、"补料法"和"添加碳酸氢盐"4种不同培养模式对魏氏真眼点藻生长和油脂积累的影响,本文分别采用不同初始浓度的硝酸钠供应、更换培养基、分次少量补加硝酸钠及添加低浓度Na HCO3或NH4HCO3等方法培养魏氏真眼点藻。结果显示,"批量"培养下,硝酸钠浓度为3.0 mmol/L时藻细胞生物量达到8.41 g/L,油脂最高可达到65.16%,油脂产率为0.30 g·L-1·d-1。"两步法"和"补料法"培养对藻细胞油脂积累没有显著影响,而通过"添加碳酸氢盐"培养对该藻细胞生长和油脂积累的效果最显著,其中Na NO3+NH4HCO3组生物量达到11.56 g/L,油脂最高达60.92%,与相同氮浓度"批量"培养相比,生物质浓度提高了1.0 g/L,总脂含量提高了10%,大大提高了该藻的总脂产率(达到0.39 g·L-1·d-1)。因此,魏氏真眼点藻是一株高产油藻株,当添加低浓度碳酸氢铵时最有利于促进该藻生物质浓度和总脂含量的提高,这是一种最佳的培养模式,具有潜在的开发和利用价值。

Growth and Oil-production Characteristics of Eustigmatos vischeri Hibberd under Different Cultivation Modes

We investigated the biological characteristics of the alga Eustigmatos vischeri Hibberd, and explored the effects of four cultivation modes (batch, two-stage, fed-batch and bicarbonate-addition culture) on its growth and lipid accumulation. We cultured E. vischeri by supplying different initial sodium nitrate, which was replaced with fresh medium, with a small amount of sodium nitrate and low concentrations of sodium bicarbonate or ammonium bicarbonate added. The biomass concentration in the batch culture reached 8.41 g/L, while the highest total lipid content was 65.16% and productivity was 0.30 g·L^-1·d^-1. Compared to the batch culture, the two-stage and fed-batch cultures had no significant effect on lipid accumulation in E. vischeri. However, the bicarbonate-addition culture did have a significant effect on growth and lipid accumulation, especially maximum biomass concentration in the NaNO₃+NH₄HCO₃ group, which reached 11.56 g/L, and total lipid content reached 60.92%. Thus, the biomass concentration and total lipid content increased by almost 1.0 g/L and 10%, respectively, compared with that in the batch culture under the same nitrogen concentration. In addition, the productivity of total lipids also increased (0.39 g·L^-1·d^-1). Our results indicated that E. vischeri is an oleaginous microalga with high development and utilization value. Moreover, the addition of a low concentration of ammonium bicarbonate promoted the growth and lipid accumulation of E. vischeri, and is thus a suitable method for cultivation.