Indiabix_Biochemical Engineering (Numerical Answers)

Given an enzyme with a Km = 10m M and Vmax = 100 m mol/min. If [S] = 100 m M, which of the following will be true?

a. A 10-fold increase in Vmax would increase velocity 10-fold y

b. A 10-fold decrease in Km would increase velocity

c. Both (a) and (b)

d. A 10-fold increase in Vmax would decrease velocity 20-fold

a. A 10-fold increase in Vmax would increase velocity 10-fold y

An enzyme is assayed at an initial substrate concentration of 2 x 10-5M. In 6-minute, half of the substrate is used. The Km for the substrate is 2 x 10-3M. The value of k in minute is

a. 0.115

b. 0.42

c. 0.093

d. 6.693

a. 0.115

If a reaction occurs in the absence of inhibitor with rate ν0 and in the presence of inhibitor with rate νi, the degree of inhibition is defined as

a. (ν0 - νi)/ν0

b. (ν0 + νi)/ν0

c. (ν0νi)/ν0

d. (ν0-νi)/νi

a. (ν0 - νi)/ν0

The rate equation in competitive inhibition based on Michaelis Menten equation is given by

a. rmaxS/(Km(1+I/Ki) +S))

b. rmaxE/(Km(1+I/Ki) +S))

c. rmaxI/(Km(1+I/Ki) +S))

d. rmaxS/(Km(1+I/Ki))

a. rmaxS/(Km(1+I/Ki) +S))

In the steady state the material balance equation for any component of a system is

a. rate of addition + rate of removal - rate of formation = 0

b. rate of addition - rate of removal + rate of formation = 0

c. rate of addition + rate of removal + rate of formation = 0

d. none of the above

b. rate of addition - rate of removal + rate of formation = 0

For an enzyme that displays Michaelis-Menten kinetics, the reaction velocity (as a fraction of Vmax) observed at [S] = 2 KM will be

a. 0.09

b. 0.33

c. 0.66

d. 0.91

c. 0.66

An enzyme has a Km of 4.7 x 10-5M. If the Vmax of the preparation is 22m moles liter-1 min-1, what velocity would be observed in the presence of 2.0 x 10-4M substrate and 5.0 x 10-5M of a competitive inhibitor?

a. 13.54μ moles liter-1min-1

b. 6.68μ moles liter-1min-1

c. 7.57μ moles liter-1min-1

d. 17.8μ moles liter-1min-1

a. 13.54μ moles liter-1min-1

The rate equation in non-competitive inhibition based on Michaelis Menten equation is given by

a. rmaxS/ (Km + S) (1+I/Ki)

b. rmaxE/ (Km (1+I/Ki) +S))

c. VmaxS/ (Km + S) (1+I/Ki)

d. rmaxS/Km

a. rmaxS/ (Km + S) (1+I/Ki)

The slope of Lineweaver Burk plot for Michaelis Menten equation is

a. Vmax/Km

b. Km/Vmax

c. 1/Km

d. Km•Vmax

b. Km/Vmax

The initial velocity, V0, of an enzyme catalyzed reaction reaches Vmax as

a. [S] = KM

b. [S] = 10 * KM

c. 1/[S] = 1/KM

d. 1/[S] → 0

d. 1/[S] → 0

Michaelis Menten equation can also be written as

a. (-Cs)/r = (Cs/rmax)+(Km/rmax)

b. 1/r = (1/rmax)+(Km/(rmax.Cs))

c. r = rmax-(Km.r/Cs)

d. All of these

d. All of these

When substrate [S] = KM (Michaelis-Menten constant), the velocity of an enzyme catalyzed reaction is about

a. 0.1 * Vmax

b. 0.2 * Vmax

c. 0.5 * Vmax

d. 0.9 * Vmax

c. 0.5 * Vmax

when [S] = Km: v = Vmax/2

The viscosity of water at STP is approximately

a. 0.005 kg.m-1.s-1

b. 0.001 kg.m-1.s-1

c. 0.003 kg.m-2.s-1

d. 0.1 g.cm-1.s-1

b. 0.001 kg.m-1.s-1

Which of the following refers to pseudo steady state?

a. d(CE)/dt = 0

b. d(Cp)/dt = 0

c. d(CES)/dt = 0

d. d(Cs)/dt = d(CES)/dt

c. d(CES)/dt = 0

The equation for the rate of product formation for simple enzyme reaction is given by (Where rmax, maximum reaction rate, Cs substrate concentration, Cp product concentration ES, CES enzyme-substrate concentration)

a. rp = rmax Cs/(Km+Cs)

b. rp= rmax CES/ (Km+ CES)

c. rp = rmax Cs/(Km+CES)

d. rp = rmax Cs/(Km+Cp)

a. rp = rmax Cs/(Km+Cs)

When [S] = 0.1 *KM, the velocity of an enzyme catalyzed reaction is about:

a. 0.1 * Vmax

b. 0.3 * Vmax

c. 0.5 * Vmax

d. 0.7 * Vmax

a. 0.1 * Vmax

The SI unit for viscosity is

a. kg.m-1. s-1

b. kg.m-2. s-2

c. kg.m-3. s-1

d. kg.m-1.s-2

a. kg.m-1. s-1

A liquid is flowing at 11,400 l.h-1 along a pipeline having a diameter of 4 cm. If the liquid has a density of 1 g.ml-1 and viscosity of 0.001kg.m-1.s-1, then the liquid would be in the

a. laminar phase

b. transient phase

c. turbulent phase

d. any of the phase

c. turbulent phase

A stirred tank reactor containing a fluid with a density of 2.5 g.ml-1 and viscosity of 0.002 kg m-1s-1 is mixed at 120 rpm. If the fluid is mixed with an impeller having diameter 50 cm, then the Reynolds number of the liquid in the reactor is

a. 2500

b. 100

c. 12,50,000

d. 1,000,000

c. 12,50,000

Reynolds number for laminar flow over a plate should be less than

a. 500 mm

b. 5 x 10-5

c. 5 x 105

d. 5 m

c. 5 x 105

Reynolds number for turbulent flow over a plate should be more than

a. 5 x 10-5

b. 106

c. 5 x 105

d. 500

b. 106

Transient flow range of mixing speed is obtained for

a. Rei < 10

b. 10 < Rei < 104

c. Rei > 104

d. None of these

b. 10 < Rei < 104

Laminar flow range of mixing speed is obtained for

a. Rei < 10

b. 10 < Rei < 104

c. Rei > 104

d. None of these

a. Rei < 10

Turbulent flow range of mixing speed is obtained for

a. Rei < 10

b. 10 < Rei < 104

c. Rei > 104

d. None of these

c. Rei > 104

For laminar flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Rei is Reynolds number for agitator; Di, stirrer diameter; and N, stirrer speed).

a. 𝑁𝑃 = 𝐾(𝑅𝑒𝑖)−1

b. 𝑁𝑃 = 𝑁2𝐷𝑖(𝑅𝑒𝑖)−1

c. 𝑁𝑃 = 𝐾(𝑅𝑒𝑖)

d. 𝑁𝑃 = 𝐾𝐷𝑖(𝑅𝑒𝑖)−2

a. 𝑁𝑃 = 𝐾(𝑅𝑒𝑖)−1

For turbulent flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Rei is Reynolds number for agitator; Di, stirrer diameter; and N, stirrer speed).

a. 𝑁𝑃 = 𝐾(𝑅𝑒𝑖)−1

b. 𝑁𝑃 = 𝑁2𝐷𝑖(𝑅𝑒𝑖)−1

c. 𝑁𝑃 = 𝐾

d. Can't be correlated.

c. 𝑁𝑃 = 𝐾

Fermenter should be filled with medium up to

a. 65-70%

b. 70-75%

c. 75-80%

d. 80-85%

c. 75-80%

The height to diameter ratio (H/D) for the column fermenters is

a.

b. >3

The height to diameter ratio (H/D) for the tank fermenters is

a.

a.

What is the ratio of depth of liquid in vessel to the diameter of tank (H:Dt)?

a. 1:1

b. 2:1

c. 4:1

d. None of these

a. 1:1

What is the ratio of diameter of impeller to the diameter of tank (Da:Dt)?

a. 1:3

b. 2:1

c. 4:1

d. 1:5

a. 1:3

Population doubling time, td can be expressed as (where μ is the specific growth rate.)

a. log2/μ

b. ln2/μ

c. μ/ln2

d. μ/log2

b. ln2/μ

The number of baffles in a standard stirred tank bioreactor is

a. 8

b. 6

c. 4

d. 2

c. 4

A functional relationship between the specific growth rate and essential compounds concentration was proposed by Monod in

a. 1958

b. 1946

c. 1942

d. 1950

c. 1942

If the specific growth rate, μ. is constant with time during the exponential growth period, the equation correlating bacterial number density Cn), cell number concentration with respect to time can be expressed as

a. Cn= Cn0 exp [μ (t - t0)]

b. Cn0 = Cn exp [μ (t - t0)]

c. Cn/Cn0 =(1/μ) exp(t-t0)

d. Cn0 / Cn = (1/μ) exp(t-t0)

a. Cn= Cn0 exp [μ (t - t0)]

The diameter of the baffles in a standard stirred tank bioreactor ranges from

a. 1/10th - 1/12th of the tank diameter

b. 1/3rd - 1/4th of the tank diameter

c. 1/15th - 1/20th of the tank diameter

d. 1/20th - 1/25th of the tank diameter

a. 1/10th - 1/12th of the tank diameter

Maintenance cost varies from

a. 0-4% of the capital cost

b. 12-16% of the capital cost

c. 4-8% of the capital cost

d. 8-12% of the capital cost

c. 4-8% of the capital cost

For cost analysis in a fermenter system, the depreciation cost varies from

a. 5-6% of the capital cost

b. 6-7% of the capital cost

c. 6-10% of the capital cost

d. 8-10% of the capital cost

c. 6-10% of the capital cost

Start up expenses in a fermentation industry varies from

a. 0-5% of the capital cost

b. 10-15% of the capital cost

c. 5-10% of the capital cost

d. 15-20% of the capital cost

c. 5-10% of the capital cost

The optimum wet solid content for the cell suspension for a bead mill is typically somewhere between

a. 5-15% by volume

b. 15-30% by volume

c. 30-60% by volume

d. 60-90% by volume

c. 30-60% by volume

Assuming the laminar flow across the filter, the rate of filtration (dVf/dt) can be expressed as a function of pressure drop Dp by the modified D'Arcy's equation as (where A is the area ofiltering surface, K is the D'Arcy's filter cake

permeability and Lis the thickness of the filter cake)

a. (1/A) dVf/dt = Δp/μ(L/K)

b. dVf/dt = (1/A)Δp/μ(L/K)

c. (1/A) dVf/dt = Δp/μ LK

d. dVf/dt = (1/A)Δp/μ LK

a. (1/A) dVf/dt = Δp/μ(L/K)

Filtration leaf test results indicate that the filtration rate of a protein product is 100 dry lbs/(ft2 hr). What size production filter would be required to obtain 100 dry lbs of filter cake/hr?

a. 1.54 ft2

b. 3.08 ft2

c. 65 ft2

d. 65 lbs/ ft2.hr

a. 1.54 ft2

If the solute passes through membrane freely, the the rejection coefficient (s) is

a. 1

b. 0

c. >1

d.

c. >1

If the membrane rejects all solute, the rejection coefficient (s) is

a. 1

b. 0

c. >1

d.

a. 1

For the extractions operation, the selectivity should be

a. > 1

b. < 1

c. 1

d. Zero

a. > 1

For a steady state condition, the change of substrate concentration (dCS/dt) is

a. Zero

b. 1

c. > 1

d. < 1

a. Zero

In antibiotic manufacturing processes, the fermentation time ranges from

a. 2-3 weeks

b. 1-2 weeks

c. 4-5 weeks

d. 2-4 weeks

c. 4-5 weeks

The conventional filtration involves the separation of large particles generally

a. dp>5μm

b. dp>10μm

c. dp>15μm

d. dp>20μm

b. dp>10μm

Micro filtration refers to the separation of suspended material such as bacteria by using a membrane with spore sizes of

a. 0.02 to 10μm

b. 1-10A°

c. 20-30μm

d. 10-200A°

a. 0.02 to 10μm

The solvent flux across the membrane can be expressed as (where A is the area, Lp is the membrane permeability, σ is the reflection point, Δp is applied pressure and Δπ is the osmotic pressure)

a. J = Lp(Δp - σΔπ)

b. J/A = Lp(Δp - σΔπ)

c. J= Lp/σΔπ

d. J/A = Lp/Δp

a. J = Lp(Δp - σΔπ)

The purity of a solute collected between two times t1 and t2 during chromatographic separation can be calculated as

a. amount of solute eluted - amount of impurity eluted

b. amount of solute eluted / amount of impurity eluted

c. amount of solvent eluted + amount of impurity eluted

d. amount of solvent eluted / amount of impurity elute

b. amount of solute eluted / amount of impurity eluted

The correlation often employed to correlate adsorption data for protein is (where Ymax is the maximum amount of solute adsorbed per mass of adsorbent, X is the mass fraction of solute in the diluent phase in solute-free basis, KL is a constant and Y is the equilibrium value of the mass of solute adsorbed per mass of adsorbent)

a. Y = YmaxX/(KL+X)

b. Y= Ymax/(KL+X)

c. Y= YmaxX/KL

d. Y = Ymax- X/ (KL+X)

a. Y = YmaxX/(KL+X)

A typical tubular centrifuge has a bowl of 2 to 5 inch in diameter and 9 to 30 inch in height with a maximum rotating speed of

a. 15,000 to 50,000 rpm

b. 50,000 to 100,000 rpm

c. 100,000 to 150,000 rpm

d. 150,000 to 200,000 rpm

a. 15,000 to 50,000 rpm

If Damkohler number, NDa >>1, the reaction rate is much greater than the mass transfer rate and the overall reaction is controlled by the rate of mass transfer. In this case, the enzyme reaction can be described as (where Csb and Cs are the substrate concentration in bulk of solution and at the immobilized enzyme surface respectively. ks mass transfer coefficient, and a is the surface area of an immobilized enzyme particles)

a. rp = kₛa(Cₛᵦ-Cₛ)

b. rp = kₛaCₛᵦ

c. rp = kₛaCₛ

d. rp = kₛa(Cₛᵦ+Cₛ)

b. rp = kₛaCₛᵦ

In batch culture, protogon is produced from peptone during the stationary phase with a yield of 0.4 protogon mg per g of peptone. If it is to be produced in a chemostat at a dilution rate of 0.5 h-1 from a medium containing 10 g/L of peptone, then the rate of protogon synthesis would be

a. 0 g/L-h

b. 0.5 g/L-h

c. 1 g/L-h

d. 2 g/L-h

a. 0 g/L-h

A continuous reactor has a dilution rate of 0.5/h. Its residence time would be

a. ln(2)/0.5

b. ln(2) x 0.5

c. 0.5 h

d. 2 h

d. 2 h

Which of the following is used to calculate mass of substrate in the reactor?

a. Flow rate x substrate concentration in the reactor

b. Volume of reactor x substrate concentration in reactor

c. Flow rate x mass of reactor

d. Volume of reactor x flow rate

b. Volume of reactor x substrate concentration in reactor

In a continuous reactor, the medium contains 40 g/L of maltose and the medium flow rate is 10 liters per hour and the effluent contains 20 g/L of

lactate. What is the productivity of lactate production from this reactor?

a. 50 g-maltose/L

b. 50 g-lactate/L

c. 200 g-maltose/L

d. 200 g-lactate/L

d. 200 g-lactate/L

A fed-batch reactor containing 1 g/L of substrate in 2 liter of medium. It is fed with 1 g/L of substrate at the rate of 1 liter per hour. After 10 hours, the concentration of substrate in the reactor was 0.5 g/L. the mass of substrate that

was used by the culture in the reactor was

a. 2g

b. 6g

c. 8g

d. 12g

b. 6g

In fed-batch fermentation, mass of substrate utilized is calculated using the relationship

a. Initial mass of substrate in the reactor + final mass of substrate in the reactor + flow rate x [substrate in the feed].

b. Initial mass of substrate in the reactor - final mass of substrate in the reactor + flow rate x [substrate in the feed]

c. Initial mass of substrate in the reactor + final mass of substrate in the reactor - flow rate x [substrate in the feed]

d. Initial mass of substrate in the reactor + final mass of substrate in the reactor - flow rate

b. Initial mass of substrate in the reactor - final mass of substrate in the reactor + flow rate x [substrate in the feed]

A chemostat has a liquid volume of 2 liters and is being fed at a rate of 4 liters per hour. Dilution rate for this reactor will be

a. 2 liters

b. 2 liters per hour

c. 2 h-1

d. 4 liters per hour

c. 2 h-1

The growth of an organism on glucose is described by the following Monod model parameters: 𝜇𝑚 = 0.5 ℎ−1 and 𝐾𝑆 = 0.1 𝑔.𝑙−1, if the concentration of glucose in the feed is 10 g/L and the dilution rate is set to 0.4/h, then the steady state concentration of glucose in the effluent will be

a. 0 g/L

b. 0.5 g/L

c. 1.0 g/L

d. 10 g/L

b. 0.5 g/L

A continuous reactor at steady state contains 0.04 g/L of biomass and 0.02 g/L of phenol. The feed contained 0.1 g/L of phenol. The biomass yield would be

a. 0.4 g/g

b. 0.5 g/g

c. 1.0 g/g

d. 5.0 g/g

b. 0.5 g/g

On a glucose medium, the growth of an organism is characterized by the following Monod model and stoichiometric parameters

𝜇𝑚 = 0.3 ℎ−1, 𝐾𝑆 = 0.05 𝑔.𝑙−1 and 𝑌𝑋 = 0.3 𝑔.𝑔−1.

When this organism is grown in a 2-liter continuous on a medium containing 10 g/L of glucose added at 1 L/h, the steady state concentration of biomass in the reactor will be

a. 0 g/L

b. 0.4 g/L

c. 0.5 g/L

d. 10 g/L

a. 0 g/L

Unsteady state mass balance for dynamic model of continuous stirred tank reactor (CSTR) is

a. Time rate of total amount in reactor = rate of addition to reactor - rate of removal + rate of formation

b. Total amount in reactor = rate of addition to reactor - rate of removal + rate of formation

c. Rate of total amount in reactor = rate of addition to reactor - rate of removal + rate of formation

d. None of the above

a. Time rate of total amount in reactor = rate of addition to reactor - rate of removal + rate of formation

A fed-batch reactor initially contains 2 liter of medium. If it was fed at 1 liter per hour, then after 10 hours, the volume of the reactor will be

a. 1 liter

b. 2 liter

c. 3 liter

d. 13 liter

b. 2 liter

In a glucose-yeast extract medium, Lactococcus lactis has a maximum specific growth rate (µm) of 1.23/h. what would be the specific growth rate

of this organism at steady state in a 4-liter reactor being fed at 2 liters per hour?

a. 0.5/h

b. 1.2/h

c. 2.4/h

d. 4/h

a. 0.5/h

A strain of Escherichia coli has a maximum specific growth rate of 0.8/h on a glucose based medium. If this organism is being grown in a chemostat with a dilution rate of 1.2/h, then at steady state the concentration of E. coli in the

same medium will

a. Increase

b. Be zero

c. Change randomly

d. Decrease

b. Be zero

A fed-batch reactor containing 2 liters of medium and 0.1 g/L of biomass is fed with a medium containing 1 g/L of substrate at 1 liter per hour. If after 10 hours, the concentration of biomass in the reactor was 0.2 g/L, then the biomass produced during the 10-hour period is

a. 1.5 g

b. 2.2 g

c. 3.0 g

d. 6.0 g

b. 2.2 g

Two continuous bioreactors containing the same organisms, fed with the same feed at the same dilution rate were compared. Reactor 1 started with an initial concentration of glucose of 10 g/L, while reactor 2 contained 0.1 g/L of glucose at the start of the process then at steady state

a. The concentration of glucose in reactor 1 would be greater than that in reactor 2.

b. The concentration of glucose in reactor 1 would be equal to reactor 2.

c. The concentration of glucose in reactor 1 would always be zero.

d. The concentration of glucose in reactor 1 would be less than that in reactor 2.

b. The concentration of glucose in reactor 1 would be equal to reactor 2.

The concentration of biomass in a continuous stirred tank reactor is 20 g dry weight per liter. What would be the concentration of biomass in the effluent?

a. Greater than 20 g dry weight per liter.

b. Approximately 20 g dry weight per liter.

c. Lesser than 20 g dry weight per liter.

d. More than 30 g dry weight per liter.

b. Approximately 20 g dry weight per liter.

Pseudomonas aeruginosa has a maximum specific growth rate of 0.8/h in a medium with glucose as a growth limiting substrate. To prevent washout, the dilution rate must be set to

a. Greater than 0.8/h

b. Less than 0.8/h

c. Equal to 0.8/h

d. 1.6/h

b. Less than 0.8/h

The range of width for the baffle in the fermenter is ___ times of vessel diameter.

a. 1/10 to 1/12

b. 1/8 to 1/10

c. 1/5 to 1/8

d. None of these

a. 1/10 to 1/12

The oxygen uptake requirements of a microbial population is characterized by the following parameters: µm = 0.2 h-1, K0 = 0.2 mg O2 L-1, Y0 = 0.5 mg dry weight/mg O2 and C0,crit = 0.8 mg L-1. The required concentration of cells is 1000 mg L-1 and the saturation oxygen concentration of the medium is 5.8 mg L-1. The required KLa must be greater than

a. 64 h-1

b. 32 h-1

c. 16 h-1

d. 8 h-1

a. 64 h-1

If liquid density and viscosity remains constant, then the Reynolds number in a stirred tank reactor will vary with the

a. Impeller diameter

b. Square root of the impeller diameter

c. Square of the impeller diameter

d. Cube of the impeller diameter

c. Square of the impeller diameter

At 25°C, the saturation concentration of oxygen in water is 1.26 mmol/L and the partial pressure of oxygen is 1 atm. The Henry's law constant will be

a. 0.793 atm-L/mmol

b. 0.207 atm-L/mmol

c. 1.26 atm-L/mmol

d. 8.74 atm-L/mmol

a. 0.793 atm-L/mmol

The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively)

a. H = (Zf-Zl)/Zf

b. H = Zf/Zl

c. H = Zf/ZfZl

d. H =(Zf+Zl)/Zf

a. H = (Zf-Zl)/Zf

In a two-phase system where the continuous phase remains in place, the gas hold up can be expressed as (where VS and Vt are the superficial gas velocity and bubble rise velocity).

a. 𝐻 = 𝑉𝑆/(𝑉𝑆 − 𝑉𝑡)

b. 𝐻 = 𝑉𝑆/(𝑉𝑆 + 𝑉𝑡)

c. 𝐻 = 𝑉𝑆/(𝑉𝑆𝑉𝑡)

d. 𝐻 = (𝑉𝑆 + 𝑉𝑡)/𝑉𝑆

b. 𝐻 = 𝑉𝑆/(𝑉𝑆 + 𝑉𝑡)

Which of the following will have the largest interfacial area per unit volume?

a. A bubble with a diameter of 1 mm.

b. A bubble with a diameter of 5 mm.

c. A bubble with a diameter of 15 mm.

d. A bubble with a diameter of 50 mm.

a. A bubble with a diameter of 1 mm.

The specific death rate of an organism can be expressed as

a. ln(2)/D

b. D/ln(2)

c. Dln(2)

d. 2.0.3/ln(2)

a. ln(2)/D

The interception efficiency can be expressed as (where dP is the particle diameter and DC cylindrical collection diameter).

a. 𝑑𝑃/𝐷𝐶

b. 𝑑𝑃 × 𝐷𝐶

c. 𝑑𝑃/𝐷𝐶 × 100

d. 𝑑𝑃𝐷𝐶/100

a. 𝑑𝑃/𝐷𝐶

A reactor has a total volume of 50,000 liters. If it has a headspace volume of 10,000 liters, then volume of liquid in the reactor will be

a. 10,000 L

b. 20,000 L

c. 30,000 L

d. 40,000 L

d. 40,000 L

A cylindrical reactor has a liquid volume of 100,000 liters. It has an aspect ratio, the ratio of the channel height to width of 1:1. The height of the liquid in the reactor will be approximately:

a. 1.0 m

b. 3.0 m

c. 5.0 m

d. 7.0 m

c. 5.0 m

A cylindrical reactor fitted with Rushton Turbine has a liquid volume of 100,000 liters. It has an aspect ratio (the ratio of the channel height to the width) of 2:1. The diameter of the impeller should be approximately:

a. 1.3 m

b. 3.3 m

c. 5.3 m

d. 7.3 m

a. 1.3 m

In the design of a paddle agitator, the ratio of paddle diameter to tank diameter is normally taken as

a. 0.1

b. 0.8

c. 0.25

d. 0.5

b. 0.8

Industrial paddle agitators turn at the speed of

a. 20 and 150 rpm

b. 150 and 300 rpm

c. 400 and 800 rpm

d. 1150 rpm

a. 20 and 150 rpm

Larger propellers turn at the speed of

a. 20 to 150 rpm

b. 150 to 300 rpm

c. 400 to 800 rpm

d. 1150 rpm

c. 400 to 800 rpm

Small propellers turn at the speed of either

a. 20 or 150 rpm

b. 150 or 300 rpm

c. 400 or 800 rpm

d. 1150 rpm or 1750 rpm

d. 1150 rpm or 1750 rpm

A fermentation system has a KLa of 3 s-1 and a CO* of 5 ppm of O2. If the bulk liquid is completely depleted of oxygen, then the oxygen transfer rate will be equal to

a. Zero

b. 15 mg L-1 s-1

c. 10 mg L-1 s-1

d. 5 mg L-1 s-1

b. 15 mg L-1 s-1

A fermentation system has a KLa of 3 s-1 and a CO* of 5 ppm of O2. If the bulk liquid is saturated with oxygen, then the oxygen transfer rate will be equal to

a. Zero

b. 3 mg L-1 s-1

c. 5 mg L-1 s-1

d. 15 mg L-1 s-1

a. Zero

During aeration, a cylindrical reactor had a height of 10 m. Without aeration, the height was 7.5 m. Under these aeration and mixing conditions, the gas hold up in the reactor is

a. 100%

b. 75%

c. 50%

d. 25%

d. 25%

In a bioreactor, if at a particular time the oxygen transfer rate is 23 kg h-1, then the oxygen uptake will be

a. 23 kg h-1

b. Less than 23 kg h-1

c. Greater than 23 kg h-1

d. 2.3 kg h-1

a. 23 kg h-1

If the packing density (α) is defined as the volume of the fiber unit volume of filter bed, the velocity with the filter void space is equal to (where V1 is velocity in fluid void space and V0 is undisturbed fluid velocity).

a. V = V0/(1-α)

b. V-V0 = 1 - α

c. V = V0(1 - α)

d. V = V0/(1 + α)

a. V = V0/(1-α)

The typical size of particles collected by diffusion mechanism is

a. < 0.25 µm

b. < 0.5 µm

c. < 0.75 µm

d. < 1 µm

b. < 0.5 µm

The X90 value for a filtration system is

a. The time required to reduce microbial population by 90%.

b. The time required to traverse survivor curve by one log cycle.

c. The depth required to reduce population by 90%.

d. The depth of the filter required to reduce population by 99%.

c. The depth required to reduce population by 90%.

For laminar flow of Newtonian fluid through a smooth round pipe, the ratio of average fluid velocity to the maximum velocity is

a. 0.5

b. 0.75

c. 0.87

d. 0.37

a. 0.5

The reduction of number of cells from 1010 to one will result into the del factor (∆) of

a. 1

b. 10

c. 23

d. 103

c. 23

The highest temperature which appears to be feasible for batch sterilization is

a. 121°C

b. 100°C

c. 105°C

d. 130°C

a. 121°C

The radius of the filter with a depth of 14 cm required for a volumetric airflow rate of 10 m3/min is approximately

a. 1.6 m

b. 0.6 m

c. 3 m

d. 6 m

b. 0.6 m

Typical aeration rates for aerobic fermentation are

a. 0 - 0.5 vvm

b. 0.5 - 1.0 vvm

c. 1.0 - 1.5 vvm

d. 1.5 - 2.0 vvm

b. 0.5 - 1.0 vvm