以异养细胞作为种子的椭圆小球藻产油脂光自养培养优化

Optimization of photoautotrophic lipid production of Chlorella ellipsoidea seeded with heterotrophic cells

摘要:

异养细胞种子/光自养培养方法是一种可异养培养的能源微藻培养的有效方法，但已有文献尚未从工艺优化角度考察其发展潜力。为了获得较高细胞密度的用于光自养培养的种子和提高光自养培养的细胞密度与油脂产率，对异养细胞种子/光自养培养的培养基和培养条件进行了优化。结果表明，采用优化后的培养基，椭圆小球藻在摇瓶中异养培养的最高藻细胞密度可达11.04 g/L，比在原始培养基条件下提高了28.0%，在5 L发酵罐中异养培养的藻细胞密度达到73.89 g/L；在2 L柱式光生物反应器中光自养培养的藻细胞密度、油脂含量和油脂产率分别达1.62 g/L、36.34%和6.1 mg/(L·h)，油脂成分主要为含C16-C18碳链的脂肪酸，是制备生物柴油的理想原料。经过优化，异养细胞种子/光自养培养这一方法能够显著地提高椭圆小球藻产油脂的能力，这进一步表明异养细胞种子/光自养培养方法有望成为可异养的能源微藻的高效培养方式。

Abstract:

Photoautotrophic cultivation with heterotrophic cells as seeds (heterotrophic cells / photoautotrophic cultivation) is an effective way for the development of microalgal biofuel, but its development potential from the point of process optimization has not been investigated in literatures. To evaluate this, the optimizations of medium and culture conditions for Chlorella ellipsoidea were studied. In the heterotrophic stage, the biomass concentration reached 11.04 g/L with the optimized medium in flask, which were 28.0% higher than that with the original medium, and the biomass concentration reached 73.89 g/L in 5-L fermenter. In the photoautotrophic stage, the culture medium and conditions were studied in a 2-L column photobioreactor. The maximum biomass concentration, lipid content and lipid productivity reached 1.62 g/L, 36.34% and 6.1 mg/(L·h) under the optimal photoautotrophic conditions. The lipids were mainly composed of C16-C18 fatty acids, which were raw material suitable for biodiesel. After optimization, heterotrophic cells / photoautotrophic cultivation can significantly improve the capacity of biofuel production by Chlorella ellipsoidea, this method is also expected to be an efficient way for the cultivation of other microalgae that can grow heterotrophically.