A 15-m ³ chemostat is operated with dilution rate 0.1 h^-1. A continuous steriliser with steam injection and flash cooling delivers sterilized medium to the fermenter. Medium in the holding section of the steriliser is maintained at 130⁰C The concentration of contaminants in the raw medium is 10⁵ ml^-l; an acceptable contamination risk is one organism every 3 months. The Arrhenius constant and activation energy for thermal death are estimated to be 7.5 × 10³⁹ h^-1 and 288.5 kJ gmol^{- 1}, respectively. The steriliser pipe inner diameter is 12 cm. At 130⁰C the liquid density is 1000 kg m^{- 3} and the viscosity is 4 kg m^{- 1} h^{- 1}. Assuming perfect plug flow, determine the length of the holding section.   __________________

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#Question id: 14403

#Section 5: Bioprocess Engineering and Process Biotechnology

Invertase is immobilised in ion-exchange resin of average diameter 1 mm. The amount of enzyme in the beads is measured by protein assay as 0.05 kg m ^-3. 20 cm ^3 beads are packed into a small column reactor; 75 ml sucrose solution at a concentration of 16 mM is pumped rapidly through the bed. In another reactor an identical quantity of free enzyme is mixed into the same volume of sucrose solution. Assume the kinetic parameters for free and immobilised enzyme are equal: K,,, is 8.8 mM and the turnover number is 2.4 x 10 gmol glucose (g enzyme)-'s^-1. The effective diffusivity of sucrose in the ion-exchange resin is 2 x 10^-6cm2s 4. What is the rate of reaction by free enzyme? 

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#Question id: 14404

#Section 5: Bioprocess Engineering and Process Biotechnology

Ultrafiltration is used to filtrate molecules of size 

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#Question id: 14405

#Section 5: Bioprocess Engineering and Process Biotechnology

If frequency adopted risk of contamination is 1 in 1000. For unsterile broth which having 10^11 viable organism then calculate the del factor? 

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#Question id: 14406

#Section 2: General Biology

Some members of the genus Proteus, as well as other genera, can lose their cell walls and swell into irregularly shaped cells called as 

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#Question id: 14407

#Section 2: General Biology

Most gram-negative bacteria are not as susceptible to penicillin as gram-positive bacteria are because

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#Question id: 14408

#Section 2: General Biology

Acid-fast bacteria such as Mycobacterium can be stained with