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, what is the upper limit for viscosity of the suspension if adequate mixing is to be maintained?

#Question id: 14268

#Part-B Specialized Branches in Biotechnology

An activated-sludge waste treatment system is required to reduce the amount of BOD₅ from 1000 mg/l to 20 mg/l at the exit. The sedimentation unit concentrates biomass by a factor of 3. Kinetic parameters are µ_m = 0.2 h-1 , K_s = 80 mg/l, k_d = 0.01 h-1 , and Y ^M _X/S = 0.5 g MLVSS/g BOD₅. The flow of waste water is 10000 l/h and the size of the treatment basin is 50,000 l. What is the value of the solids residence time?

#Question id: 14272

#Part-B Specialized Branches in Biotechnology

Penicillin is produced by P. chrysogenum in a fed-batch culture with the intermittent addition of glucose solution to the culture medium. The initial culture volume at quasi-steady state is V0 = 500 l, and glucose-containing nutrient solution is added with a flow rate of F = 50 l/h. Glucose concentration in the feed solution and initial cell concentration are S0 = 300 g/l and X0 = 20 g/l, respectively. The kinetic and yield coefficients of the organism are mm = 0.2 h-1 , KS = 0.5 g/l, and YX/S = 0.3 g dw/g glucose. If qP = 0.05 g product/g cells h and P₀ = 0.1 g/l, determine the product concentration in the vessel at t = 10 h

#Question id: 14278

#Part-B Specialized Branches in Biotechnology

Stirrer has a power number (Np) 10. If the stirrer speed (N) is 1s^-1, its diameter D=1m and the density of the medium is 1000 kg/m^3, the ungassed power input (P) in watts is 

#Question id: 14278

#Part-A Aptitude & General Biotechnology

Stirrer has a power number (Np) 10. If the stirrer speed (N) is 1s^-1, its diameter D=1m and the density of the medium is 1000 kg/m^3, the ungassed power input (P) in watts is 

#Question id: 14279

#Part-B Specialized Branches in Biotechnology