How to properly sterilize a bioreactor? Did you do it right?

Sterilization operation of the bioreactor is an essential link before carrying out the biological reaction experiment. If the sterilization operation is not in place, it is easy to contaminate the fermentation products during the operation of the bioreactor, resulting in greater losses. Therefore, it is very important to find the skills of sterilization. Next, we will briefly discuss the sterilization steps of the bioreactor.

Sterilization steps for bioreactors

STEP 1

Remove the stirring motor of the bioreactor, lay it flat on the table, wrap the motor interface with tinfoil and bind it with a rubber band to prevent it from falling off during the sterilization process, so as to eliminate the damage to the motor interface caused by high-temperature steam generated during high-pressure steam sterilization.

STEP 2

Remove the temperature sensor from the tank. The temperature sensor does not directly contact the fermentation broth and does not require sterilization.

STEP 3

To install the pH electrode:
There is a rubber ring protection between the pH electrode and the panel;
Be sure to tighten the upper and lower fixing nuts of the electrode;
The pH electrode cable interface is wrapped with tin foil and tied with a rubber band to prevent the sterilization process from falling off and affecting the performance of the electrode;
The pH electrode should be calibrated before sterilization.

STEP 4

To install the DO electrode:
There is a rubber ring protection between the DO electrode and the panel;
Be sure to tighten the upper and lower fixing nuts of the electrode;
The DO electrode cable interface is wrapped with tin foil and tied with a rubber band to prevent the sterilization process from falling off and affecting the electrode performance;
Calibration of DO electrode after sterilization;
Before sterilization, pay attention to whether the electrolyte in the dissolved oxygen electrode still exists, if not, add it.

Remove the defoaming or liquid level cable, and insert the defoaming or liquid level cable to the bottom. After sterilization, it is positioned to the required height and then do not press it again. The height of the defoaming electrode is about 1.5cm from the liquid surface.

STEP 5

STEP 6

Remove the cooling water inlet and outlet pipes on the bioreactor and the inlet and outlet pipes on the condenser in turn. When removing, clamp the joints of the removed water pipes with clips to prevent water from flowing out.

STEP 7

Remove the air tube from the luer connector, and clamp the silicone tube of the air inlet with a hose clamp. The silicone tube and the air filter are sterilized together with the glass jar. The exhaust port is also clamped with a hose clamp, and then the silicone tube is sterilized with the air filter. Put the exhaust filter into the sterilizer together.

STEP 8

The mouth of the four-way feeding tube can be blocked with a silicone tube, or it can be sterilized together with the feeding bottle (one end of the feeding bottle is connected to the breathing valve), and the treatment should be carried out according to the working conditions (if it is sterilized together with the feeding bottle, the feeding end must be sterilized together with the feeding bottle). Use hose clamps).

STEP 9

Use hose clamps to clamp the panel end of the harvest tube and the spare nozzle respectively.

STEP 10

Before sterilization, the position of the stirring blade should be adjusted. The lower stirring blade should be installed at the bottom of the stirring shaft as much as possible, and the upper stirring blade should be adjusted to the middle position of the added fermentation liquid.

STEP 11

Before sterilization, tighten the six retaining nuts of the bioreactor.

STEP 12

Before sterilization, the flame inoculation port must be loosened to prevent the pressure difference between the inside and outside of the tank from being too large;
Usually high temperature and high pressure sterilization at 121 ℃, 20min (the specific time is adjusted according to the medium composition);
After sterilization, the temperature of the fermentation tank may be high, do not touch it directly, wait for the equipment to cool down, and wear protective gloves before operating;
After sterilization, tighten the flame inoculation port as soon as possible to prevent contamination.