Up - General

Question 1

[Fermentation] What is DOT?

Answer 1

Dissolved Oxygen Tension - partial pressure of oxygen in liquid as % were 100% is saturation

Question 2

[OTR] What is kLa and how can it be measured?

Answer 2

Volumetric oxygen transfer coefficient.

Steady-state: Balance oxygen in, inside and out
- Expensive equipment

Sulphite oxidation: Measure by titration
- Not possible with living organisms (not actual media)

Dynamic: Steady, off and then on. Plot CL over t to get -qx and dCL/dt = OTR - qx
+ Specific conditions!

Question 3

[OTR] What affects the oxygen transfer (7)?

Answer 3

Gas flow rate: Positve (not too large - go through)

Stirring speed: Positive (shear stress)

Medium and biomass: Viscosity and [salt] (sol.) negative

Bioreactor design: Positive height:width + baffles

(Anti) foam: Small bubbles positive but foam, antifoam large bubbles (less area, less kLa)

Pressure: Positive (<2 bar)

O2 in gas: Positive