How can you maintain sterility in a bioreactor?

Additionally, Based on the production system’s specifications: e.g., the ratio of tank diameter to maximal liquid height (aspect), impeller and sparger types, and design and placement of probes and ancillary equipment within a vessel shall be considered. The FDA also endorses computer-based and virtual simulations. Computational fluid dynamics (CFD) simulations for calculating energy dissipation rates (EDR) can be a useful scaling approach because EDR is a scalar quantity (unit: W/m3) that corresponds well to fluid hydrodynamic conditions Refer : CBER/CDER/CVM 2011. Guidance for Industry: Process Validation — General Principles and Practices, US Food and Drug Administration, Rockville.

In some cases, the sterility controls begin before the bioreactor. An example is media preparation where single use powder transfer bags can be used for charging media into a mixer. By sterilzing the powder transfer bags via gamma irradiation or even x-ray, possible bioburden is reduced. This can be critical to reduce the loading on the sterile filtration as it is fed to the bioreactor and mitgating risk of contamination.

Most standard bioreactor and fermenter designs include a spray device and piping connection package with recommended CIP supply flow rate and pressure requirements. So the validation shall consider these requirements. Important is to optimise the cycle times, Optimizing cycle times which increases system productivity by minimizing the time and utilities needed to rinse and wash the process equipment. Usually , A system’s cleaning cycle parameters for a process are first developed based on the initial coupon studies performed, which provide parameters for TACT (Time, Action, Chemical, Temperature). These parameters can be optimized in the field during the commissioning process.

In general the final Water rinse sample needs to have test results adhered to WFI specification especially BET, Microbial,pH and conductivity

Reactor cleaning is mainly done with water, regardless of the other cleaning agents used. Water is present in most phases. The last rinse must comply with WFI requirements, which do not imply sterility. WFI has both microbiological and endotoxin limits. It is not advisable to leave the reactor wet, even with a very low bioburden. The sterilization cycle should start as soon as possible and preferably within a defined and validated timeframe.

Rouging is a common phenomenon in most stainless steel equipment, especially if they are regularly treated with water and steam. You should check for rouging in a defined and regular manner and perform system (reactor, piping, and similar) passivation if necessary.

In my view we may need to consider regulations too. In A recent FDA guidance for industry on process validation which outlines a plan for equipment qualification and lists expectations for five items studies/ tests, criteria, timing, responsibilities, and procedures for documenting and approving the qualifications. In line with those regulatory guidelines and expectations validations protocols shall be designed as a basic requirement. You should scientifically justify your validation approach and its specific components (e.g., parameters selection, ranges to be tested, and experimental design) and tailor them to your specific platform, process, and product.

Surprisingly this post doesn’t mention validation of sterilization of the bioreactor prior to use which is often dismissed as an excessive requirement. That is plainly wrong, it has to start out sterile or nothing else matters. Steam-in-place without definitive evidence of effectiveness is a common shortcut and contributes to contamination later on.

Maintaining sterility in bioreactors is key for biotechnological cultivation. Key strategies include: Sterilization: Sterilize components using autoclaving or gamma irradiation. Biosecurity: Limit access to trained personnel; employ monitoring systems. Bio-burden Control: Monitor and reduce bioburden using filtration and UV light. Biosafety: Utilize containment systems; equip personnel with PPE. Cleaning and Maintenance: Schedule routine cleaning; conduct equipment checks. Technology and Automation: Minimize human intervention through automation; employ real-time monitoring for critical parameter control. Implementing these strategies ensures sterility, biosecurity, and biosafety in bioreactor operations.

Basics essential to establishment and maintenance of process asepsis include the integrity of the process envelope and services and robust aseptic practice A new ASME U stamped mammalian cell culture reactor had repeated contamination; a lengthwise seam had occurred along the vessel weld. This crack was invisible as it was under the coded jacket and insulation and belly band. Under jacket sterilization steam pressure, it closed. when the jacket cooled, it opened, bleeding cooling glycol into the vessel A new media vessel had chronic contamination. The tank OEM sanitary ferrule angle differed enough from the sanitary diaphragm valve ferrule angle such that after the junction had cooled post steam sterilization a gap occured at the gasket