7a201-mt----microbial Bioreactors Engineering

NR

Code No: 7A201/MT

M.Tech. – II Semester Regular Examinations, September, 2008 MICROBIAL BIOREACTORS ENGINEERING (Biotechnology) Time: 3hours

Max. Marks:60 Answer any FIVE questions All questions carry equal marks ---

1.

Discuss the CSTR designs for enzyme catalysed reactions. Add a note on CSTR cell reactors with recycle.

2.a)

Discuss the ‘Dynamic Method’ for measuring the mass transfer coefficient (KLa). A fermenter containing bacterial culture used for the production of an organic acid. Air flow is shut off for a few minutes and the dissolved oxygen level drops. The air supply is then reconnected. When steady state is established, the dissolved oxygen tension is 82% air saturation and the following results are observed.

b)

Time (s) Oxygen tension ( % air saturation)

10

25

60

73

With the given data, estimate the KLa using dynamic method. 3.

What is the importance of heat transfer in microbial bioreactors? Give some examples of heat – transfer configurations.

4.

Discuss various important factors to be considered in scale – up of microbial bioreactors. What are the difficulties associated with scale – up of a bioreactor?

5.

A stirred – tank reactor is to be scaled down from 10m3 to 0.1m3. The dimensions of the large tank are Dt = 2m, Di = 0.5m, N = 100rpm. a) Determine the dimensions of the small tank (Dt, Di, H) by using geometric similarity. b) What would be the required rotational speed of the impeller in the small tank if the following criteria were used. i) Constant tip speed ii) Constant impeller Renumber. Contd…2.,

Code No: 7A201/MT

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6.

Write about various possible measuring devices and probes for monitoring and control of chemical environment in a bioreactor.

7.

Design a bioreactor for the production of secondary metabolites using non – filamentous fungi. Add a note on the product recovery.

8.

Explain about various products of animal cell cultures with suitable examples. $$$