Perfusion Seed Culture for High-Density Fed-Batch Bioproduction
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Solution Overview
Problem
Traditional batch or fed-batch production processes in bioreactors face challenges in achieving high viable cell densities in the N-1 seed train stage, leading to inefficient production due to prolonged unproductive growth phases and reduced volumetric productivity.
Innovation Solution
Culturing CHO cells in a N-1 culture vessel to achieve at least 25 x 10^6 viable cells/ml, with nutrient supplementation and waste product removal, and maintaining lactate levels below 15 mM, followed by inoculating a N culture vessel at 8.5 x 10^6 viable cells/ml, and optionally using a perfusion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional batch or fed-batch N-1 seed train cultures are used, then the process is simple to operate, but high viable cell densities cannot be achieved
Solution Approach 1:
The patent implements perfusion culture that continuously removes waste products (lactate, ammonia) and supplements nutrients, fundamentally changing the cultural parameters from static batch/fed-batch to dynamic perfusion conditions. This enables sustained high viable cell densities (≥25×10^6 cells/ml) by maintaining optimal metabolic environment throughout the culture period
Solution Approach 2:
The perfusion process operates continuously with constant medium exchange, ensuring uninterrupted nutrient supply and waste removal. This continuous action maintains cells in a productive state longer than discontinuous batch processes, achieving higher cell densities without proportionally increasing operational complexity
2Productivity
If the unproductive growth phase is extended in the production bioreactor, then cell mass accumulates sufficiently, but the production duration increases and volumetric productivity decreases
Solution Approach 1:
The patent performs the growth phase in advance in the N-1 seed train bioreactor using perfusion culture to achieve high viable cell densities before inoculation into the production bioreactor. This preliminary accumulation of cell mass at high density allows the production phase to begin immediately with cells already in a productive state, eliminating the need for an extended unproductive growth phase in the production bioreactor
Solution Approach 2:
The patent segments the culture process into distinct stages: N-1 seed train stage for high-density cell accumulation using perfusion, and N production stage for bioproduct generation. By separating the growth and production functions into different bioreactors with optimized conditions for each, the system achieves high volumetric productivity without extending total production duration
3Quantity of substance
If perfusion culture is implemented in the N-1 seed train stage, then high viable cell densities are achieved, but the device complexity increases
Solution Approach 1:
The patent employs a single perfusion-capable bioreactor design that serves dual purposes: as an N-1 seed train bioreactor for high-density cell cultivation and potentially as an N production bioreactor. This multi-functional equipment reduces overall system complexity compared to having separate specialized bioreactors for each stage, as the same hardware platform can be reused across different process phases
Data Source
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AI summary
Methods of improving the efficiency of production of a protein product of interest in mammalian cell culture are presented. In particular, the methods result in an increase in the quantity of a protein product produced, or decreases protein product production time in a manufacturing-scale bioreactor cell culture. The disclosed methods comprise: (a) culturing the N-1 bioreactor culture to high viable cell densities; and (b) seeding the production bioreactor culture at high viable cell seeding densities.