E. coli have a maximum respiration rate, qO2max, of about 240-mg O2/g-dry wt-h. It is desired to achieve a cell mass of 20 g dry wt/l. The kLa is 120 h-1 in a 1000-l reactor (800 l working volume). A gas stream enriched in oxygen is used (i.e., 80% O2) which gives a value of C* = 28 mg/L. If oxygen becomes limiting, growth and respiration slow; for example,

                                     

   where CL is the dissolved oxygen concentration in the fermenter. What is CL when the cell mass is  at 20 g/l?

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#Question id: 14736

#Section 2: General Biology

In basal structure of flagella of gram positive bacteria?

1. L

2. P

3. S

4. M

Which combination is not found in above bacteria? Choose the option with both incorrect rings.

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#Question id: 14737

#Section 2: General Biology

Which structures are involved in formation of biofilms

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#Question id: 14741

#Section 5: Bioprocess Engineering and Process Biotechnology

Microbial cell recovery is carried out in a continuous disc-stack centrifuge. The centrifuge is operated at 5000 rpm for separation of baker's yeast. At a feed rate of 60 1/min, 50% of the cells are recovered. At constant speed, solid recovery is inversely proportional to flow rate. What operating speed is required to recover 90% of cells if the flow rate in the centrifuge is maintained at 601/min? 

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#Question id: 14742

#Section 5: Bioprocess Engineering and Process Biotechnology

Gel chromatography is used for hormone separation. A pilot-plant scale gel chromatography column packed with sephacryl resin is used to separate two hormones, A and B. The column is 5 cm in diameter and 30 cm in height: V, = 1.9x 10-⁴m³, Wr = 3x10^-3m³ /kg dry sephacryl, ps =1.25 x 10³ kg/m³ . The partition coefficients are k_pA =0.38 and k_pB= 0.15. If the eluting flow rate is 0.7 I/h, what is the retention time for each hormone? 

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#Question id: 14743

#Section 5: Bioprocess Engineering and Process Biotechnology

for the fermenter with the given data. 

Air is sparged with 0.4 vvm, it is equipped with two sets of impellers and a flat-blade turbine with four baffles. calculate power, P 

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#Question id: 14744

#Section 5: Bioprocess Engineering and Process Biotechnology

For production of an enzyme used for synthesis of a sun protection lotion, the required kinetic data and constants are: 

vmax = 2.3 mmol.m^-3 s^-1 Km = 8.9 mmol.^-1 So = 12 mmol1- 

Find the reaction time for 95% conversion of raw material