A bacterial culture having a specific oxygen uptake rate of 5 mmol O2 (g DCW)-1 hr-1 is being grown aerobically in a fed-batch bioreactor. The maximum value of the volumetric oxygen transfer coefficient is 0.18 s-1 for the stirred tank bioreactor and the critical dissolved oxygen concentration is 20% of the saturation concentration (8 mg mL-1). The maximum density to which the cells can be grown in the fed-batch process without the growth being limited by oxygen transfer, is approximately

In a well aerated and agitated microbial culture, the 'supply' of oxygen is equal to 'demand' (uptake) of the growing culture. The K_La for such a system will be (K_La = volumetric mass transfer coefficient, C* = dissolved oxygen concentration in liquid in equilibrium with gaseous oxygen, C = instantaneous value of dissolved oxygen concentration, 'r' = specific oxygen uptake rate per unit weight of cells, X = dry weight of the cells per unit volume)

A

$$\frac{{\left( {rX} \right)}}{{\left( {C* - C} \right)}}$$

B

$$\frac{{\left( r \right)}}{{X\left( {C* - C} \right)}}$$

C

$$\frac{{\left( {C* - C} \right)}}{{\left( {rX} \right)}}$$

D

$$\frac{{\left( X \right)}}{{r\left( {C* - C} \right)}}$$

A strain of Azotobacter vinelandii is cultured in a 15 m3 stirred fermenter for alginate production. Under current operating conditions kLa is 0.17 s-1. Oxygen solubility in the broth is approximately 8 x 10-3 kg m-3. The specific rate of oxygen uptake is 12.5 mmol g-1 h-1. What is the maximum possible cell concentration?

A

10 gl-1

B

15 gl-1

C

20 gl-1

D

12 gl-1

A bacterial culture with an appropriate biomass composition of CH_1.8O_0.5N_0.2 is grown aerobically on a defined medium containing glucose as the sole carbon source and ammonia being the nitrogen source. In this fermentation, biomass is formed with a yield coefficient of 0.35 gram dry cell weight per gram of glucose and acetate is produced with a yield coefficient of 0.1 gram acetate per gram of glucose. The respiratory coefficient for the above culture will be

A

0.90

B

0.95

C

1.00

D

1.05

In a batch process, the reaction takes place in the presence of an acid medium. The acid is drained from the reaction vessel at the rate of 15ml/s as a result of the density difference of the acid from the reacting component. To avoid wastage of acid, it is recycled to an acid tank which has 1000 L capacity. The acid drained from the reaction vessel, picks up 50 g/L solids from the reactor. Acid is fed once again to the process from acid tank. When the process is started, the acid is almost pure in the tank as a result of filtration. As the reaction proceeds, acid in the tank gets more and more contaminated with the solids. The concentration of the solids should not exceed 100 g/L from the process point of view. The batch time is 16h. Estimate whether the concentration of the solids will exceed 100g/L during the batch reaction.

A

37.04 h

B

30.05 h

C

36.04 h

D

32.05 h

Wash out (as defined by D = μ_max) of a continuous stirred tank fermenter is characterized by (X = biomass, S = substrate concentration in bioreactor, S₀ = substrate concentration in feed, P = product concentration in bioreactor).

A

X = 0, S = 0, P = 0

B

X = 0, S = S0, P = 0

C

X = 0, S

D

X

What is/are the following differences between private and public limited companies?
1. In a private limited company there is restriction on the number of members, where as no such restriction is applicable on a public limited company.
2. A private limited company can be listed on a stock exchange, where as a public limited company is always listed on a stock exchange.
3. A private limited company cannot issue debentures, whereas a public limited company can issue debentures.

A

1 only

B

2 and 3 only

C

1 and 3 only

D

1, 2 and 3

Which of the following statement(s) is/are CORRECT for antigen activated effector T cells?
P. CD4+ cells make contact with macrophages and stimulate their microbicidal activity.
Q. CD4+ cells make contact with B cells and stimulate them to differentiate into plasma cells.
R. CD8+ cells make contact with B cells and stimulate them to differentiate into plasma cells.
S. CD8+ cells make contact with virus infected cells and kill them.

A

Q only

B

Q and S only

C

P, Q and S only

D

P, Q, R and S

Refer to Q8 and, calculate the bacteria suffer growth inhibition after copper sulphate is accidently added to the fermentation broth. This causes a reduction in oxygen uptake rate to 3 mmol g-1 h-1. What maximum cell concentration can now be supported by the fermenter?

A

50 gl-1

B

10 gl-1 [ 25 gl-1 d) 55 gl-1

C

9. Refer to Q8 and, calculate the bacteria suffer growth inhibition after copper sulphate is accidently added to the fermentation broth. This causes a reduction in oxygen uptake rate to 3 mmol g-1 h-1. What maximum cell concentration can now be supported by the fermenter? a) 50 gl-1 b) 10 gl-1 b) 25 gl-1

D

55 gl-1

Ahar culture, Kayatha culture, Malwa culture, Savalda culture, Jorwa culture, Prabas culture, Rangpur culture are all parts of:

A

Lower Paleolithic Cultures

B

Middle Paleolithic Cultures

C

Upper Paleolithic Cultures

D

Chalcolithic Cultures

Ahar culture, Kayatha culture, Malwa culture, Savalda culture, Jorwe culture, Prabhas culture, Rangpur culture are all :

A

Mesolithic cultures

B

Palaeolithic cultures

C

The Chalcolithic cultures of Ancient India

D

None of these