Abstract: High-density cell culture could reduce the cost of large-scale cultivation of microalgae for biodiesel. Aeration is one of the important factors in high-density culture of microalgae. Chlorella vulgaris was cultured for 15 days in a novel concentric-tube photobioreactor with BG11 medium. The effect of different aeration intervals on cell density of Chlorella vulgaris，pH and dissolved oxygen changes of medium was studied. Air was passed into the concentric-tube photobioreactor at aeration flow rate 10L/min for 0.5h each aeration. The aeration manner of the novel concentric-tube photobioreactor could exclude dissolved oxygen timely. When biomass accumulation was stable，the pH of culture medium was substantially constant；the cell density was 7.22×106 cells/mL at aeration interval 0.5h. Compared to the cell concentration at aeration interval 1h，1.5h，2h，the cell concentrations at aeration interval 0.5h increased by 9.56%，41.02%，122.1%，respectively. Therefore，with the decrease of aeration interval time，concentration of Chlorella vulgaris increased.

Key words: microalgae cultivation, Chlorella vulgaris, aeration interval, cell density, novel concentric-tube photobioreactor

摘要： 细胞高密度培养有利于降低微藻规模化培养成本及其生物柴油制造的成本，曝气是影响微藻规模化高密度培养的重要因素之一。以普通小球藻（Chlorella vulgaris，FACHB-1227）为研究对象，采用BG11培养基，于新型套管式沿程曝气光生物反应系统中，以细胞密度为检测指标，实验研究了曝气间隔时间对藻液中细胞密度、藻液pH值、溶氧量变化的影响。控制每次曝气时气体流量为10L/min、持续时间为0.5h，培养周期为15天。结果表明，藻液中积累的溶解氧能够及时排除，进入生物质积累稳定期时，藻液的pH值基本恒定；微藻生长稳定期时（培养12天），曝气间隔0.5h时细胞密度为7.22×106个/mL，相比于1h、1.5h、2h分别提高了9.56%、41.02%和122.1%。可见，适当减少曝气间隔时间，可显著提高藻细胞密度。

关键词: 微藻培养, 普通小球藻, 曝气间隔, 细胞密度, 新型套管式光生物反应器