Which method is better for kLa determination?

The dynamic gassing-out method has the advantage over the previous methods of determining the KLa during an actual fermentation and may be used to determine K L a values at different stages in the process.

What is kLa method?

In submerged fermentation, four methods are available to estimate the overall oxygen mass transfer coefficient (KLa): the dynamic method, the stationary method based on a previous determination of the oxygen uptake rate (QO2 X), the gaseous oxygen balance and the carbon dioxide bal- ance.

What is the significance of calculation kLa in bioreactor operation?

Measurements of kLa provide important information about a bioprocess or bioreactor. These determinations ensure that processing conditions are such that an adequate supply of oxygen is available for proliferation of cells. The kLa value can also be used to optimize control variables over the lifecycle of a bioprocess.

What is mass transfer coefficient in bioreactor?

The kLa (Volumetric Mass Transfer Coefficient) and the OTR (Oxygen Transfer Rate) detail how efficient oxygen is transferred from the gas bubbles into the bioreactor medium, i.e. how much oxygen is available for the cultivated biomass.

How kLa can be measured by sulfite oxidation method?

The chemical method is known as the sulfite oxidation method. It involves the determination of the maximum rate of oxidation of sodium sulfite to sodium sulfate in the presence of c0so4 or CuSO4 catalyst, in which there is no back pressure of dissolved oxygen.

What is the proper concentration unit of kLa?

What is the proper concentration unit of kLa? Explanation: In this relation, the volumetric oxygen transfer coefficient, kLa, has the units of mmol, of O2/ml.

What is kLa bioreactor?

kLa is a gas transfer coefficient, a measurement of the capacity of the bioreactor to transfer oxygen into the cultures. kLa is influenced by factors such as bioreactor geometry, gas flow, superficial gas velocity, impeller type and speed, and power input for mixing per unit reaction volume.

What factors affect kLa?

Here are four key variables that can affect kLa values:

• Gas bubble size. When gas bubble size decreases, surface area and gas residency time increases, causing bubbles to stay in the culture longer.
• Mixing.
• Air flow rate.
• Properties of the liquid or medium.

What is the unit of kLa?

Explanation: In this relation, the volumetric oxygen transfer coefficient, kLa, has the units of mmol, of O2/ml. h. unit concentration gradient. Using the proper concentration units, kLa has the unit of reciprocal of time (i.e., time-1).

How do you measure kLa?

So, kLa=OUR/(C*-CL) and OUR is generally calculated as OUR=qO2*Cx. Therefore, kLa=qO2*Cx/(C*-CL), where qO2 is the specific oxygen uptake rate of oxygen and Cx is the biomass concentration.