Inloes D S, Smith W J, Taylor D P, Cohen S N, Michaels A S, Robertson C R
Departments of Chemical Engineering and Genetics, Stanford University, Stanford, California 94305.
Biotechnol Bioeng. 1983 Nov;25(11):2653-81. doi: 10.1002/bit.260251113.
Actively growing Escherichia coli C600(pBR322), immobilized within the macroporous matrix of asymmetric-wall hollow-fiber membranes, has been propagated to extremely high densities, typically more than 10(12) cells/mL of accessible void volume, in some regions cells accounting for nearly 100% of the available macrovoid volume forming a tissue-like mass. Production rates of beta-lactamase, an enzyme used as an indicator of the culture's biosynthetic potential, remained at high and relatively stable levels for more than three weeks of continuous operation, and effluent supernatant enzyme activities attained 25% of the accumulated level measured in a 24-h shaker-flask culture. Based on the accessible void volume within the fiber wall, the beta-lactamase productivity was independent of the specific asymmetric membrane used. On a per cell basis, however, cells cultured using hollow-fiber membranes were only 10% as productive as those in the shaker-flask culture, possibly due to the high packing density or culture aging. By contrast, the hollow-fiber bioreactor was 100 times more productive than the shaker-flask culture on a reactor-volume basis, primarily as a consequence of the high cell densities. Reactor productivity was dependent on the number of cells in the reactor, suggesting that reactor performance was kinetically controlled and not mass transport limited.
将处于活跃生长状态的大肠杆菌C600（pBR322）固定在非对称壁中空纤维膜的大孔基质内，已繁殖到极高的密度，通常每毫升可利用的空隙体积中细胞数超过10¹²个，在某些区域，细胞几乎占可用大孔体积的100%，形成类似组织的团块。β-内酰胺酶是一种用作培养物生物合成潜力指标的酶，在连续运行三周多的时间里，其生产率保持在较高且相对稳定的水平，流出物上清液中的酶活性达到了在24小时摇瓶培养中测得的累积水平的25%。基于纤维壁内可利用的空隙体积，β-内酰胺酶的生产率与所使用的特定非对称膜无关。然而，以每个细胞为基础，使用中空纤维膜培养的细胞的生产率仅为摇瓶培养中细胞的10%，这可能是由于高堆积密度或培养老化所致。相比之下，基于反应器体积，中空纤维生物反应器的生产率比摇瓶培养高100倍，这主要是高细胞密度的结果。反应器的生产率取决于反应器中的细胞数量，这表明反应器性能受动力学控制而非传质限制。
