Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition you have a wild type (Lac+) strain carrying a Tn5 insertion known to be near several Lac genes on the E. coli chromosome. You grow P1 phage on this strain and use the resulting phage lysate to infect the lac1– strain, selecting for kanamycin resistance (Kanr). Among 100 Kanr transductants, you find that 82 are Lac– and 18 are Lac+. Express the distance between Tn5 and the lac1– mutation as a cotransduction frequency;

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#Question id: 15465

#SCPH05 I Biotechnology

50 g benzaldehyde vapour is condensed at 179°C. What is the enthalpy of the liquid relative to the vapour?  (Standard latent heat for vaporisation for benzaldehyde is 38.40 kJ gmol^-1)

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#Question id: 15466

#SCPH05 I Biotechnology

Water at 25°C enters an open heating tank at a rate of 10 kg h^-1. Liquid water leaves the tank at 88°C at a rate of 9 kg h^-1; 1 kg h^-1 water vapour is lost from the system through evaporation. At steady state, what is the rate of heat input to the system?

h (liquid water at 25°C = 104.8 kJ kg^-1) 

h (liquid water at 88°C = 368.5 kJ kg^-1) 

h (saturated steam at 88°C = 2656.9 kJ kg^-1)

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#Question id: 15467

#SCPH05 I Biotechnology

Fumaric acid is produced from Malic acid using Fumarase. Calculate standard heat of reaction for the following transformation:

C₄H₆O₅ → C₄H₄O₄ + H₂O

Given: (Δhc°)malic acid= -1328.8 kJ/gmol 

   (Δhc°)Fumaric acid= -1334.0 kJ/gmol

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#Question id: 15468

#SCPH05 I Biotechnology

In downstream processing of gluconic acid, concentrated fermentation broth containing 20% (w/w) gluconic acid is cooled in a heat exchanger prior to crystallisation. 2000 kg h^-1 liquid leaving an evaporator at 90°C must be cooled to 6°C. Cooling is achieved by heat exchange with 2700 kg h^-1 water initially at 2°C. The final temperature of the cooling water is 50°C. 

Assume (heat capacity of gluconic acid is 0.35 cal g^-1 °C^-1).

h (liquid water at 90°C = 376.9 kJ kg^-1)

h (liquid water at 6°C = 25.2 kJ kg^-1)

h (liquid water at 2°C = 8.4 kJ kg^-1 )

h (liquid water at 50°C = 209.3 kJ kg^-1)

h (gluconic acid at 90°C=0)

How much heat is removed to the cooling water?

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#Question id: 15469

#SCPH05 I Biotechnology

What is the rate of heat loss from the gluconic acid solution to the surroundings? 

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#Question id: 15470

#SCPH05 I Biotechnology

In the stoichiometric equation given below identify which one of the following corresponds to oxygen balance:

CwHxOyNz + aO2 + bHgOhNi cCHαO_βN_δ + dCO₂ + eH₂O