Simulated oxygen and glucose gradients as a prerequisite for predicting industrial scale performance a priori

Abstract

Transferring bioprocesses from lab to industrial scale without loss of performance is key for the successful implementation of novel production approaches. Because mixing and mass transfer is usually hampered in large scale, cells experience heterogeneities eventually causing deteriorated yields, that is, reduced titers, productivities, and sugar‐to‐product conversions. Accordingly, reliable and easy‐to‐implement tools for a priori prediction of large‐scale performance based on dry and wet‐lab tests are heavily needed. This study makes use of computational fluid dynamic simulations of a multiphase multi‐impeller stirred tank in pilot scale. So‐called lifelines, records of 120,000 Corynebacterium glutamicum cells experiencing fluctuating environmental conditions, were identified and used to properly design wet‐lab scale‐down (SD) devices. Physical parameters such as power input, gas hold up, , and mixing time showed good agreement with experimental measurements. Analyzing the late fed‐batch cultivation revealed that the complex double gradient of glucose and oxygen can be translated into a wet‐lab SD setup with only few compartments. Most remarkably, the comparison of different mesh sizes outlined that even the coarsest approach with a mesh density of was sufficient to properly predict physical and biological readouts. Accordingly, the approach offers the potential for the thorough analysis of realistic industrial case scenarios.

Metabolic engineering of Vibrio natriegens

“…Eventually, successfully developed lab-scale processes have to be transferred to industrial scale. Thus, scale up studies need to provide a comprehensive understanding of the metabolism and its regulation under fluctuating process conditions such as substrate, oxygen and CO 2 /HCO 3 − gradients as typically found in large-scale bioreactors (Figure 3; [51][52][53]). To satisfy the demand of V. natriegens for sodium ions, most cultivation media are supplemented with at least 15 g NaCl l −1 .…”

Monitoring Intracellular Metabolite Dynamics in Saccharomyces cerevisiae during Industrially Relevant Famine Stimuli

“…More precisely, the exposure of individual microorganisms to substrate gradients can be recorded during all process phases and expressed as lifelines [ 36 ]. Currently, this approach reaches considerable agreement with quantitative data on concentration gradients from pilot to industrial scale [ 37 , 38 , 39 , 40 ]. An adjacent development goal is to increase the predictive power to uncover biological scale-up effects already at the development stage in the lab via data-driven models.…”

Data‐driven in silico prediction of regulation heterogeneity and ATP demands of Escherichia coli in large‐scale bioreactors

“…To detect the latter and to describe them properly in data‐driven models, experimental scale‐up simulators are necessary that mirror transcriptional and translational cellular replies as performed by Kuschel and Takors (2020). The setting of such devices may differ from “conventional” scale‐up simulators that typically mimic circulation times.…”