Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark.
Biotechnol Bioeng. 2011 Aug;108(8):1828-40. doi: 10.1002/bit.23121. Epub 2011 Mar 21.
The purpose of this article is to demonstrate how a model can be constructed such that the progress of a submerged fed-batch fermentation of a filamentous fungus can be predicted with acceptable accuracy. The studied process was enzyme production with Aspergillus oryzae in 550 L pilot plant stirred tank reactors. Different conditions of agitation and aeration were employed as well as two different impeller geometries. The limiting factor for the productivity was oxygen supply to the fermentation broth, and the carbon substrate feed flow rate was controlled by the dissolved oxygen tension. In order to predict the available oxygen transfer in the system, the stoichiometry of the reaction equation including maintenance substrate consumption was first determined. Mainly based on the biomass concentration a viscosity prediction model was constructed, because rising viscosity of the fermentation broth due to hyphal growth of the fungus leads to significant lower mass transfer towards the end of the fermentation process. Each compartment of the model was shown to predict the experimental results well. The overall model can be used to predict key process parameters at varying fermentation conditions.
本文旨在展示如何构建一个模型，以便能够以可接受的精度预测浸没式分批补料发酵过程的进展。所研究的过程是在 550L 中试工厂搅拌釜式反应器中用米曲霉生产酶。采用了不同的搅拌和通气条件以及两种不同的叶轮几何形状。生产力的限制因素是向发酵液提供氧气，而碳源进料流速由溶解氧张力控制。为了预测系统中的可用氧气传递，首先确定了包括维持底物消耗的反应方程式的化学计量。主要基于生物量浓度构建了一个粘度预测模型，因为由于真菌菌丝生长导致发酵液的粘度增加，在发酵过程的后期会导致传质显著降低。模型的每个部分都被证明可以很好地预测实验结果。该整体模型可用于预测不同发酵条件下的关键过程参数。
