The effect of hydrodynamic stress on the growth of Xanthomonas campestris cultures in a stirred and sparged tank bioreactor
The effect of hydrodynamic stress on the growth of Xanthomonas campestris cultures in a stirred and sparged tank bioreactor
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DOI：
10.1007/s00449-012-0825-y
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发表时间：
2013-07
影响因子：
3.8
通讯作者：
F. García-Ochoa;E. Gómez;A. Alcón;V. E. Santos
中科院分区：
文献类型：
--
作者：
F. García-Ochoa;E. Gómez;A. Alcón;V. E. Santos
研究了不同剪切水平下葡萄黄单胞菌在摇瓶和搅拌喷淋式生物反应器中的比生长和黄原胶产量。用摇瓶作为研究剪切效应的参考。在两种培养模式下，用观察到的生长速率与无氧限制或细胞损伤的生长速率之比表示的有效因子进行了计算。据观察，效能因子在很大程度上取决于操作条件。在低搅拌速率下，观察到强氧传递限制，有效系数降低54%。相反，在较高的搅拌速度下，细胞损伤是由肉汤湍流体中的流体动力应力引起的，当搅拌速度高于500转/分时，有效因子值再次下降。细胞形态的变化也随搅拌条件的变化而变化，在高剪切应力下，细胞形态的差异是明显的。
The specific growth and the xanthan production rates by the bacteriumXanthomonas campestrisunder different shear levels in shake flasks and in a stirred and sparged tank bioreactor have been studied. The shake flask has been used as a reference for studying the shear effects. An effectiveness factor expressed by the ratio of the observed growth rate and the growth rate without oxygen limitation or cell damage was calculated in both modes of cultures. It was observed that the effectiveness factor was strongly dependent on the operational conditions. A strong oxygen transfer limitation at low stirring rates, indicated by a 54 % decrease in the effectiveness factor was observed. In contrast, at higher stirrer speed, cell damage was caused by hydrodynamic stress in the turbulent bulk of the broth, yielding again a decrease in the effectiveness factor values for stirrer speeds higher than 500 rpm. Cell morphological changes were also observed depending on the agitation conditions, differences in morphology being evident at high shear stress.