Nehring Dirk, Czermak Peter, Vorlop Jürgen, Lübben Holger
Department of Biotechnology, University of Applied Sciences Giessen-Friedberg, Wiesenstr. 14, 35390 Giessen, Germany.
Biotechnol Prog. 2004 Nov-Dec;20(6):1710-7. doi: 10.1021/bp049762e.
The oxygen supply of cell cultures with the aid of free gas bubbles is an efficient process strategy in pharmaceutical production. If the cell-damaging impact of gas bubbles is reduced, direct aeration becomes a practical solution with scale-up potential and comparatively high oxygen transfer rates. In this paper a microsparging aeration system made of porous ceramic was compared with bubble-free membrane aeration. The sparging system was used for the long-term cultivation of mammalian cells in 2- to 100-L scale bioreactors and produced bubble sizes of 100-500 microm in diameter. Using a scale of 2.5 and 30 L, a cell density of 2.6 x 10(6) cells/mL was attained. When a 100-L scale was used, a density of 1.1 x 10(6) cells/mL was achieved, whereas a comparable membrane-aerated system showed a cell density of 2.2 x 10(6) cells/mL. At relatively low agitation rates of less than 70 rpm in the sparged bioreactors, a homogeneous and constant oxygen concentration was kept in the medium. As a result of the different foam-forming tendency caused by the lower gas flow of the ceramic sparger compared to that of the standard aeration systems, we were able to develop an appropriate process control strategy. Furthermore, oxygen transfer measurements for the common stainless steel sparger and the ceramic sparger showed a 3-fold higher oxygen transfer coefficient for the ceramic sparger.
在制药生产中，借助游离气泡为细胞培养物供氧是一种有效的工艺策略。如果能降低气泡对细胞的损伤影响，直接曝气就会成为一种具有放大潜力且氧传递速率相对较高的实用解决方案。本文将一种由多孔陶瓷制成的微泡曝气系统与无泡膜曝气进行了比较。该微泡曝气系统用于在2升至100升规模的生物反应器中对哺乳动物细胞进行长期培养，产生的气泡直径为100 - 500微米。在2.5升和30升规模下，细胞密度达到了2.6×10⁶个细胞/毫升。当使用100升规模时，细胞密度达到1.1×10⁶个细胞/毫升，而类似的膜曝气系统的细胞密度为2.2×10⁶个细胞/毫升。在微泡曝气生物反应器中，搅拌速率相对较低，低于70转/分钟时，培养基中能保持均匀且恒定的氧浓度。由于陶瓷微泡发生器的气体流量低于标准曝气系统，导致形成泡沫的趋势不同，我们得以制定出合适的过程控制策略。此外，对普通不锈钢微泡发生器和陶瓷微泡发生器的氧传递测量结果表明，陶瓷微泡发生器的氧传递系数高出3倍。
