To ensure turbulent conditions and minimum mixing time during agitation with a turbine impeller, the Reynolds number must be at least 10⁴. A stirred laboratory-scale fermenter with a turbine impeller 5 cm in diameter is operated at 800 rpm. If the density of broth being stirred is close to that of water. The mixing system is scaled up so the tank and impeller are 15 times the diameter of the laboratory equipment. The stirrer in the large vessel is operated so that the stirrer tip speed (tip speed = π N i D i) is the same as in the laboratory apparatus. How does scale-up affect the maximum viscosity. 

TLS Online TPP Program

#Question id: 14397

#Section 5: Bioprocess Engineering and Process Biotechnology

A purified hydrolytic enzyme (Mr 150 000) is available with the description: Gives a Vmax of 3 200 units/mg protein under optimal conditions. How many nmol of enzyme are there in 1 mg  

TLS Online TPP Program

#Question id: 14398

#Section 5: Bioprocess Engineering and Process Biotechnology

The internal effectiveness factor is useful because , which statement is not correct 

TLS Online TPP Program

#Question id: 14399

#Section 5: Bioprocess Engineering and Process Biotechnology

 observable Thiele modulus CD decreases when 

TLS Online TPP Program

#Question id: 14400

#Section 5: Bioprocess Engineering and Process Biotechnology

internal mass transfer effects are eliminated when the internal effective ness factor is 

TLS Online TPP Program

#Question id: 14401

#Section 5: Bioprocess Engineering and Process Biotechnology

Denitrifying bacteria are immobilised in gel beads and used in a stirred reactor for removal of nitrate from groundwater. At a nitrate concentration of 3 g m ^-3, the conversion rate is 0.011 g s-1 m-3 catalyst. The effective diffusivity of nitrate in the gel is 1.5 × 10 ^-9 m ² s^-1, the beads are 6 mm in diameter, and the liquid-solid mass-transfer coefficient is 10 ^-5 m s^-1. Km for the immobilised bacteria is approximately 25 g m ^-3. Calculate the observable Thiele modulus with CAs = 1.9 g m ^-3

TLS Online TPP Program

#Question id: 14402

#Section 5: Bioprocess Engineering and Process Biotechnology

Baby hamster kidney cells are immobilised in alginate beads. The average particle diameter is 5 mm. Rate of oxygen consumption at a bulk concentration of 8 x 10 ^-3 kg 0 2 m ^-3 is 8.4 x 10 ^-5 kg s^- 1 m^-3 catalyst. The effective diffusivity of oxygen in the beads is 1.88 x 10^ -9 m 2 s^- 1. Assume that the oxygen concentration at the surface of the catalyst is equal to the bulk concentration, and that oxygen uptake follows zero-order kinetics. calculate the observable Thiele modulus.