31. Biomass is being produced in a continuous stirred tank bioreactor of 750 L capacity. The sterile feed containing 8 g L-1 glucose as substrate was fed at a flow rate of 150 L h-1. The microbial system follows Monod's model with μm = 0.4 h-1, KS = 1.5 g L-1 and \[{Y_{\frac{X}{S}}}\] = 0.5 g cell mass-g substrate-1. Determine the cell productivity (g L-1 h-1) at steady state.
32. A bacterial culture with an appropriate biomass composition of CH1.8O0.5N0.2 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
33. Batch fermentation of glucose to ethanol yields a productivity of 4.5 g-1L h-1. If the yeast cell concentration in the fermentation broth is 5% (v/v) and the intracellular NAD+/NADH concentration in the yeast cells is 10 μM, the cycling rate of NAD+ ⇌ NADH will be
34. A roller bottle culture vessel perfectly cylindrical in shape having inner radius (r) = 10 cm and length (l) = 20 cm was fitted with a spiral film of length (L) = 30 cm and width (W) = 20 cm. If the film can support 105 anchorage dependent cells per cm2, the increase in the surface area after fitting the spiral film and the additional number of cells that can be grown respectively are
35. A protein binds to phosphocellulose column at pH 7.0 and elutes at pH 8.0. If the protein has to be further purified on a DEAE Sephacel column, the binding buffer should have a pH of
36. Which one of the following monolayer culture systems have the highest surface area to medium ratio?
37. Match the downstream processes in Group I with the products in Group II.
Group I
Group II
P. Solvent extraction
1. Lactic acid
Q. Protein-A linked affinity chromatography
2. Penicillin
R. Extractive distillation
3. Monoclonal antibody
d. S. Salting out
4. Lipase
| Group I | Group II |
| P. Solvent extraction | 1. Lactic acid |
| Q. Protein-A linked affinity chromatography | 2. Penicillin |
| R. Extractive distillation | 3. Monoclonal antibody |
| d. S. Salting out | 4. Lipase |