Nutrient medium is to be heated from 10⁰C to 28⁰C is a single-pass countercurrent shell-and-tube heat exchanger before being pumped into a fed-batch fermenter. Medium passes through the tubes of the exchanger; the shell-side fluid is water which enters with flow rate 3 x 10^4 kg h^- 1 and temperature 60⁰C pre-heated medium is required at a rate of 50 m^3 h^-1. The density, viscosity and heat capacity of the medium are the same as water; the thermal conductivity of the medium is 0.54 Wm^- 1 ⁰C^ - 1. It is proposed to use 30 steel tubes with inner diameter 5 cm; the tubes will be arranged in line. The pipe wall is 5-mm thick; the thermal conductivity of the metal is 50 Wm^- 1 ⁰C^ - 1. The maximum linear shell-side fluid velocity is estimated as 0.15 m s^-1.  Determine the heat-transfer area. ____________

#Question id: 14269

#Section 5: Bioprocess Engineering and Process 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 treatme nt basin is 50,000 l. What value of the recycle ratio must be used?

________________________

#Question id: 14271

#Section 5: Bioprocess Engineering and Process 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. Determine the concentration of cells at quasi-steady state when t = 10 h.

#Question id: 14272

#Section 5: Bioprocess Engineering and Process 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: 14273

#Section 5: Bioprocess Engineering and Process Biotechnology

Nicotiana tabacum cells are cultured to high density for production of polysaccharide gum. The reactor used is a stirred tank, containing initially 100 litres medium. The maximum specific growth rate of the culture is 0.18 d^-1 and the yield of biomass from substrate is 0.5 g g^-l. The concentration of growth-limiting substrate in the medium is 3% (w/v). The reactor is inoculated with 1.5 g l^{- 1} cells and operated in batch until the substrate is virtually exhausted; medium flow is then started at a rate of 4 l d^-1. Fed-batch operation occurs under quasi-steady-state conditions. Estimate the batch culture time.                                  ____________________

#Question id: 14274

#Section 5: Bioprocess Engineering and Process Biotechnology

Nicotiana tabacum cells are cultured to high density for production of polysaccharide gum. The reactor used is a stirred tank, containing initially 100 litres medium. The maximum specific growth rate of the culture is 0.18 d^-1 and the yield of biomass from substrate is 0.5 g g^-l. The concentration of growth-limiting substrate in the medium is 3% (w/v). The reactor is inoculated with 1.5 g l^{- 1} cells and operated in batch until the substrate is virtually exhausted; medium flow is then started at a rate of 4 l d^-1. Fed-batch operation occurs under quasi-steady-state conditions. Estimate final biomass concentration?

________________