What is oxygen transfer rate in bioreactor?
The oxygen transfer rate (OTR) through an interface is calculated as the multiplicative product of the mass transfer coefficient, the specific transfer area, and the concentration driving force. In a bioreactor for cell cultivation, oxygen is typically supplied by blowing air into the culture medium through a sparger.
What are the different methods of the measurement of the oxygen transfer coefficients in a bioreactor system?
There are many techniques for measuring oxygen concentration and OTR in bioreactors. Zirconia, electrochemical, infrared, ultrasonic and laser cells are used to measure oxygen concentration in the liquid medium. Optical sensors are better alternatives to measure oxygen concentration in small bioreactors.
Which is used in determination of oxygen transfer rate?
… The oxygen transfer rate (OTR) is proportional to the mass transfer coefficient, k L , the specific interfacial, a, and the difference between the saturation concentration and the dissolved oxygen concentration in the broth.
What is oxygen transfer rate in fermentation?
The oxygen transfer rate describes the rate of oxygen delivery from gas into liquid such as an agitated suspension culture in a bioprocess vessel. OTR is a very important parameter of fermentation vessels which affects the selection, design, and scale-up of a bioprocess protocol [1].
What is oxygen transfer in bioreactor?
Oxygen transfer is often the rate-limiting step in the aerobic bioprocess due to the low solubility of oxygen in the medium. The correct measurement and/or prediction of the volumetric mass transfer coefficient, (k(L)a), is a crucial step in the design, operation and scale-up of bioreactors.
How do you increase oxygen transfer rate in bioreactors?
3. Air flow rate. Higher oxygen availability drives kLa increases. Increasing oxygen supply to a bioreactor drives this availability and can be controlled by modifying concentration (air vs O2 enrichment) and volumetric flow.
What is Standard oxygen Transfer Rate?
The Standard Oxygen Transfer Rate (SOTR) is the rate at which the SOR is transferred in tap water at 20°C and zero DO. The Actual Oxygen Transfer Rate (AOTR or OTRf) is the rate at which AOR is transferred under field conditions.
What is oxygen uptake rate?
The Specific Oxygen Uptake Rate (SOUR), also known as the oxygen consumption or respiration rate, is defined as the milligram of oxygen consumed per gram of volatile suspended solids (VSS) per hour.
What is an oxygen transfer rate?
Oxygen transfer is often the rate-limiting step in the aerobic bioprocess due to the low solubility of oxygen in the medium. The possible increasing on OTR due to the oxygen consumption by the cells is taken into account through the use of the biological enhancement factor.
How do you increase oxygen transfer rate?
It can be increased by:
- Creating a bigger surface of gas bubbles (kLa) by increasing gas flow and stirrer speed and by adding baffles.
- Creating a higher O2 concentration gradient by adding O2 to gasmix and increasing the pressure.
What is aeration rate?
Aeration rate is defined as the gas volumetric flow rate per unit volume of culture medium (vvm) [34].
Why is oxygen transfer rate important in bioreactors?
In aerobic bioprocesses, oxygen is a key substrate; due to its low solubility in broths (aqueous solutions), a continuous supply is needed. The oxygen transfer rate (OTR) must be known, and if possible predicted to achieve an optimum design operation and scale-up of bioreactors. Many studies have be …
Do you know the oxygen transfer rate ( OTR )?
The oxygen transfer rate (OTR) must be known, and if possible predicted to achieve an optimum design operation and scale-up of bioreactors. Many studies have be …
What is the mass transfer coefficient in a bioreactor?
For this discussion the gas bubble contains oxygen, and the liquid is the liquid in a bioreactor. kLa can be represented by the following equation: kLa = kL × a Where kLa is the mass transfer coefficient from the gas to liquid phase, given in sec ‑1 kL = liquid side mass transfer coefficient (resistance in gas side film can be neglected)
Why is oxygen transfer important in aerobic bioprocesses?
Bioreactor scale-up and oxygen transfer rate in microbial processes: an overview In aerobic bioprocesses, oxygen is a key substrate; due to its low solubility in broths (aqueous solutions), a continuous supply is needed.