Abstract

The main challenge in bioreactor scale-up is maintaining the bioprocess productivity. The aim of the present work was to scale-up the protein production with enhanced proteolytic activity by phosphate addition in Jacaratia mexicana cell culture, by using the shear rate as scale-up criterion. The volumetric proteolytic activity in the J. mexicana cell culture in shake flask increased 1.9 times with increasing phosphate concentration from 1.25 to 2.5 mmol L⁻¹, while the protein concentration was similar (∼55 mg L⁻¹). This culture was scaled-up from 0.4-L to 4-L in stirred tank bioreactors at average shear rate of 200 s⁻¹ and 234 s⁻¹, respectively, increasing the phosphate concentration in the 4-L bioreactor (2.5 mmol L⁻¹) with respect to the 0.4-L bioreactor (1.25 mmol L⁻¹). There was also an increase in the volumetric proteolytic activity (2 times), without statistically significant difference in the protein concentration. Scale-up strategy and improvement of the culture medium exhibited a similar behaviour maintaining the protein productivity and increasing the proteolytic activity. These results indicate that the average shear rate is a useful hydrodynamic parameter in the scale-up of protein production of J. mexicana cell culture. Additional phosphate and bioreactor hydrodynamics could be related to unusual lengthening and thinning of most cells in the 4-L stirred tank bioreactor. Finally, the power input per unit volume in the scaled-up bioreactor decreased by 53%, improving the volumetric proteolytic activity and maintaining protein productivity. These results encourage proceeding with the scale-up process using the shear rate as a scale-up criterion.

摘要

生物反应器放大的主要挑战是保持生物过程生产力。本工作的目的是通过使用剪切速率作为放大标准，通过在Jacaratia mexicana细胞培养物中添加磷酸盐来扩大具有增强蛋白水解活性的蛋白质生产。随着磷酸盐浓度从 1.25 增加到 2.5 mmol L ^-1，摇瓶中J. mexicana细胞培养物中的体积蛋白水解活性增加了 1.9 倍，而蛋白质浓度相似（～55 mg L ^-1）。该培养物在搅拌罐生物反应器中以 200 s ^-1和 234 s ^{-1 的}平均剪切速率从 0.4-L 放大到 4-L分别相对于 0.4-L 生物反应器 (1.25 mmol L ^-1 )增加 4-L 生物反应器 (2.5 mmol L ^-1 ) 中的磷酸盐浓度。体积蛋白水解活性也增加（2 倍），蛋白质浓度没有统计学上的显着差异。培养基的放大策略和改进表现出类似的行为，保持蛋白质生产力并增加蛋白水解活性。这些结果表明，平均剪切速率是在扩大J. mexicana蛋白质生产中的一个有用的流体动力学参数细胞培养。额外的磷酸盐和生物反应器流体动力学可能与 4-L 搅拌罐生物反应器中大多数细胞的异常延长和变薄有关。最后，放大后的生物反应器每单位体积的功率输入降低了 53%，提高了体积蛋白水解活性并保持了蛋白质生产力。这些结果鼓励使用剪切速率作为放大标准进行放大过程。