Raposo S, Lima-Costa M E
Faculdade de Engenharia de Recursos Naturais, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.
Biotechnol Lett. 2006 Mar;28(6):431-8. doi: 10.1007/s10529-005-6181-0.
Centaurea calcitrapa suspension cultures were grown either in Erlenmeyer flasks or in a mechanically stirred bioreactor. Its rheological behaviour, when fitted to the Oswald-de Waele model (power law), showed pseudoplastic characteristics in both cases. The flow behaviour index (n) decreased over the course of a growth cycle and the consistency index (K) increased, reached a value of 1.81 N sn m(-2 )run on 2 l bioreactor. Bioreactor cultivation of C. calcitrapa cells at different agitation rates (30, 60, 100 and 250 rpm), highlighted the influence of shear forces on cell viability loss (90-34%) and phenol accumulation (74-140 microg l(-1)), due to increased stirring speeds. Analysis of these results suggests that this cell line is shear-sensitive. An empirical exponential correlation was defined between apparent viscosity and biomass concentration, under the studied conditions, giving the possibility to estimate the prevailing broth regime and to optimize bioreactor design.
矢车菊悬浮培养物在锥形瓶或机械搅拌生物反应器中生长。当拟合到奥斯瓦尔德-德瓦埃勒模型（幂律）时，其流变行为在两种情况下均表现出假塑性特征。流动行为指数（n）在生长周期过程中降低，而稠度指数（K）增加，在2升生物反应器中运行时达到1.81 N s n m(-2)的值。在不同搅拌速率（30、60、100和250 rpm）下对矢车菊细胞进行生物反应器培养，突出了剪切力对细胞活力损失（90 - 34%）和苯酚积累（74 - 140 μg l(-1)）的影响，这是由于搅拌速度增加所致。对这些结果的分析表明该细胞系对剪切敏感。在研究条件下，定义了表观粘度与生物量浓度之间的经验指数相关性，从而有可能估计主要的发酵液状态并优化生物反应器设计。
