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TLS Online TPP Program

#Question id: 3300

In a population individuals having heterozygous phenotype are more favored than either homozygous, under such condition-

#Section 3: Genetics, Cellular and Molecular Biology

  1. Recessive alleles would be lost from population 

  2. Dominant alleles would be lost

  3. Both alleles would remain in population       

  4. Alleles would be lost randomly

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TLS Online TPP Program

#Question id: 14236

#Section 5: Bioprocess Engineering and Process Biotechnology

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. What tube length is required? ____________
TLS Online TPP Program

#Question id: 14237

#Section 5: Bioprocess Engineering and Process Biotechnology

A genetically-engineered strain of yeast is cultured in a bioreactor at 30⁰C for production of heterologous protein. The oxygen requirement is 80 mmol 1-1 h-I; the critical oxygen concentration is 0.004 mM. The solubility of oxygen in the fermentation broth is estimated to be 10% lower than in water due to solute effects. What is the minimum mass-transfer coefficient necessary to sustain this culture if the reactor is sparged with air at approximately 1 atm pressure ?         
TLS Online TPP Program

#Question id: 14238

#Section 5: Bioprocess Engineering and Process Biotechnology

A genetically-engineered strain of yeast is cultured in a bioreactor at 30⁰C for production of heterologous protein. The oxygen requirement is 80 mmol 1-1 h-I; the critical oxygen concentration is 0.004 mM. The solubility of oxygen in the fermentation broth is estimated to be 10% lower than in water due to solute effects. What mass-transfer coefficient is required if pure oxygen is used instead of air?                       
TLS Online TPP Program

#Question id: 14239

#Section 5: Bioprocess Engineering and Process Biotechnology

A 200-1itre stirred fermenter contains a batch culture of Bacillus subtilis bacteria at 28⁰C Air at 20⁰C is pumped into the vessel at a rate of 1 vvm; (vvm stands for volume of gas per volume of liquid per minute). The average pressure in the fermenter is 1 atm. The volumetric flow rate of off-gas from the fermenter is measured as 189 l min-1. The exit gas stream is analysed for oxygen and is found to contain 20.1% 02. The dissolved-oxygen concentration in the broth is measured using an oxygen electrode as 52% air saturation. The solubility of oxygen in the fermentation broth at 28⁰C and 1 atm air pressure is 7.8 x 10-3 kg m-3. Calculate the oxygen transfer rate_____________
TLS Online TPP Program

#Question id: 14240

#Section 5: Bioprocess Engineering and Process Biotechnology

A 200-1itre stirred fermenter contains a batch culture of Bacillus subtilis bacteria at 28⁰C Air at 20⁰C is pumped into the vessel at a rate of 1 vvm; (vvm stands for volume of gas per volume of liquid per minute). The average pressure in the fermenter is 1 atm. The volumetric flow rate of off-gas from the fermenter is measured as 189 l min-1. The exit gas stream is analysed for oxygen and is found to contain 20.1% 02. The dissolved-oxygen concentration in the broth is measured using an oxygen electrode as 52% air saturation. The solubility of oxygen in the fermentation broth at 28⁰C and 1 atm air pressure is 7.8 x 10-3 kg m-3. Determine the value of kLa for the system ____________
TLS Online TPP Program

#Question id: 14241

#Section 5: Bioprocess Engineering and Process Biotechnology

Yeast cells are to be separated from a fermentation broth. Assume that the cells are spherical with diameter 5 µm and density 1.06 g cm-3. The viscosity of the culture broth is 1.36 x 10-3 N s m-2. At the temperature of separation, the density of the suspending fluid is 0.997 g cm-3. 500 litres broth must be treated every hour. Specify Σ for a suitably-sized disc-stack centrifuge

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