Day 2 (Part I)

The day started with briefing on the inoculation process. It is crucial to carry out the aseptic techniques during the inoculation process to keep the contamination risk to the minimal.

With Mr. Sharman's supervision, we inoculated the yeast culture into the bioreactor around 10.30am.

Oxygen told by Mr. Sharman is one of the main factors that control the growth rate of the culture cells in the fermenter. The higher the oxygen transfer rate, the higher the cell growth rate.

The Oxygen transfer rate which is as the KLa is controlled by a few parameters; the rotatory speed of the impeller, the air flow rate, concentration of the oxygen supplied and the pressure in the vessel.

While using Minifors for the fermentation, we can easily manipulate 3 of the above parameters, which are the rotatory speed (rpm), the air flow rate (vvm) and the concentration of oxygen supplied (either we obtain oxygen from the air or from the oxygen tank).

Minifors is built in such a way that makes controlling the fermentation process easier and more efficient. The cascade mode is making use of an intelligent technology that constantly monitor the oxygen uptake rate by the cells in the fermenter. When the oxygen update rate by the cells increases, the concentration of the oxygen in the fermenter decreases, this change is detected by the oxygen regulatory system of the fermenter. With the cascade mode technology, rotatory speed will be increased spontaneously. Thus, the oxygen diffusing rate to the media will increase as well. 


Further reading on:
1. Inoculation process, please refer to the post on "Inoculation"
2. Calibration of the PO2 probe, please refer to the post on "PO2 probe Calibration"