The maintenance core of animal and plant cell fermentation tanks isCleaning and sterilization, component maintenance, parameter calibrationIt needs to be carried out in combination with the special characteristics of cell culture (no cell wall, sensitive to shear force, easy to contaminate). The specific maintenance process and key points are as follows:
Residual liquid drainage and preliminary flushing
After fermentation, first empty the residual liquid, culture medium, and cell debris from the tank, and then useDeionized water or purified waterRepeatedly rinse the inner wall of the tank, mixing blade, baffle, sampling port and other parts to remove visible residues.
For animal cell specific air lift fermentation tanks (without stirring blades, low shear force), it is necessary to focus on flushing the micropores of the gas-liquid distributor to prevent blockage.
Chemical cleaning to remove stubborn stains
Preparation for insoluble residues such as proteins and polysaccharidesAlkaline cleaning agent(such as 0.5% -1% NaOH solution), inject into the tank until all contact areas are submerged,Cycle cleaning for 30-60 minutesIf there is a lot of residue, it can be heated to 40-50 ℃ appropriately (to avoid high temperature damage to the seal).
If there are calcium and magnesium precipitates or inorganic residues, use firstAcidic cleaner(such as 0.1% -0.5% dilute nitric acid) cycle clean for 20-30 minutes, then rinse with a large amount of purified water until neutral (pH 6.5-7.5) to prevent acid-base residue from damaging cells.
Attention: Fermentation tanks for animal and plant cellsSilicone tube, rubber sealing gasketThe components should not be exposed to strong acids or alkalis for a long time. After cleaning, they should be promptly removed and treated separately.
Sterilization to prevent the growth of miscellaneous bacteria
In situ sterilization (SIP)Priority is given to using high-temperature steam sterilization, with parameters of121℃、0.1MPa、20–30minCovering all components in contact with the culture medium, such as tanks, pipelines, valves, sensor probes, etc; For components that are not resistant to high temperatures (such as pH electrodes and dissolved oxygen electrodes), they need to be disassembled before use75% ethanol soaking or UV irradiationSterilization.
Post sterilization treatmentAfter sterilization, keep the tank dry to prevent the growth of bacteria in condensed water; If not used for a long time, sterile air can be blown into the drying jar.
Maintenance of seals and connectors
The fermentation tankCan lid sealing ring, pipeline silicone gasket, valve sealing gasketIt is a vulnerable part that needs to be inspected once a month. If there is aging, deformation, or cracking, it should be replaced immediately to prevent air and liquid leakage and pollution.
Suggested selection of sealing components for animal cell fermentation tanksMedical grade silicone or fluororubberRegularly disinfect with medical grade alcohol to prevent material leaching from affecting cell growth.
Maintenance of mixing and ventilation system
Mechanical stirring fermentation tankCheck the bearings and reduction motors of the mixing blade every quarter, and add special lubricating oil; Check if the connection between the stirring blade and the shaft is loose to prevent shear force from damaging the cells during operation.
Ventilation systemRegularly disassemble and wash the air filter (the filter element material is mostly polytetrafluoroethylene or cellulose). If the filter element is clogged or sterilized too many times, replace it in a timely manner; The micro pores of the aeration head in the air lift fermentation tank need to be cleaned with ultrasonic waves to ensure uniform ventilation.
Calibration of sensors and instruments
PH electrode, dissolved oxygen electrodeCalibrate once a month, using standard buffer solutions (pH 4.0, 7.0, 10.0) for pH electrodes, and saturated sodium sulfite solution (zero oxygen point) and air (100% dissolved oxygen point) for dissolved oxygen electrodes; Soak the electrode in protective solution before and after use to prevent it from drying up and becoming ineffective.
Temperature sensor, pressure sensorCalibrate once every quarter to ensure temperature control accuracy within ± 0.5 ℃ and accurate pressure display.
If the fermentation tank is not used for a long time (more than 1 month), it needs to be completedCleaning Sterilization Dryingtechnological process:
Apply a layer of metal components such as the inner wall of the tank and the stirring bladeFood grade rust proof oilTo prevent rusting;
After cleaning and sterilizing detachable components such as electrodes, sealing rings, and filters, they should be sealed and stored in a dry, dust-free environment.
Disconnect the power and gas sources of the fermentation tank, close all valves, and provide dust cover protection; Regularly (monthly) power on and run for 10-15 minutes to check if the motor and control system are functioning properly.
The maintenance of animal and plant cell fermentation tanks requiresDistinguish materialsGlass tanks should avoid collisions and sudden temperature changes; Stainless steel tanks cannot be brushed with steel wire balls to prevent scratching the inner wall and the growth of bacteria.
When cleaning and sterilizing, avoidCorrosive reagentsContact sensors and electrical components; It is strictly prohibited to use chlorine containing disinfectants in animal cell fermentation tanks to prevent residual chlorine from poisoning cells.
Establish a maintenance ledger to record the time of each cleaning, sterilization, component replacement, and calibration for easy traceability.