The generation of foam is common in aerobic bioreactor systems. Foaming can cause a range of problems, including increased contamination risks through potential exhaust filter fouling, poor mass transfer, product/cell entrainment, increased shearing from bursting bubbles, and cell death [1,2,3]. The development of proper methods and equipment to control foam is critical. A single-use foam probe would allow the end user to shift from a time-dependent antifoam delivery protocol developed based on educated guesses to a controlled protocol based on an output signal, resulting in greater confidence and control of the system, less antifoam consumption, and traceability of foam generation within the bioprocess.
Purpose: Cell culture and fermentation has the potential to generate foam in great quantity in stirred-tank reactors. To reduce the need for constant supervision, manual intervention, and excessive chemical anti-foam usage, an automated foam probe is proposed.
Methods: A foam detection system was designed to provide accurate and consistent results. It was designed to resist forces applied from manufacturing, shipping, and BPC installation, and to resist fouling in culture. The system was tested to automatically manage foam in several cell culture applications, and was compared to time-based anti-foam addition strategies. Comparisons included viable cell density, and amount of antifoam used.
Results: The design of the foam detection system was proven effective in standard cell culture fed-batch processes as well as ultra-high density perfusion processes. The effectiveness was proven to scale through the full range of HyPerforma™ Single-Use Bioreactors (S.U.B.). It was shown to reduce the amount of chemical anti-foam required, decrease risk, and increase confidence in bioreactor safety and functionality.