A process for the microbial synthesis of 1,3-propanediol ( 3 8 2 C H O ) uses an anaerobicfermenter with a selected strain of K. pneumoniae to convert glycerol ( 3 8 3 C H O ) to 1,3-propanediol and acetic acid ( 2 4 2 C H O ). All other byproducts are of negligible concentration.The fermentation and cell growth equation can be written:3 8 3 3 4 7 2 3 8 2 2 4 2 2 2 68 3 3 49 15 15 40 C H O NH C H O N C H O C H O CO H O + → + + + +The continuous fermentation process is set up at 37°C and atmospheric pressure.Anaerobic conditions are maintained by sparging the fermentation broth with N2 at aflowrate of 500 litres per minute. The medium, containing ammonia, is fed at 500 kg perhour, and has a composition of 14% (w/w) glycerol. Suppression of the side reactions isachieved by excess glycerol, so the liquid product contains 3% (w/w) unreacted glycerol.2a. Draw a process diagram. List all your assumptions necessary to write a materialbalance.(5 marks)2b. List your unknowns.(3 marks)2c. Write an overall materials balances for the mass flow rates of the liquid streams and thegas streams separately. Make assumptions about which terms are negligible. Write a massbalance for glycerol.(3 marks)2d. Compute the molar rate of glycerol consumption by K. pneumoniae in the fermenter.The molecular weight of glycerol is 92 g mol-1.(3 marks)2e. Compute the rate of CO2 gas rate evolution in litres per minute by the metabolism ofK. pneumoniae in the fermenter. Note that the molar volume of an ideal gas at 37°C is25.24 litres.(3 marks)2f. Estimate the flowrate V and composition of the offgas stream.(3 marks)2g. What is the minimum concentration of ammonia needed in the medium?(2 marks)2h. If the ammonia concentration is the minimum required in the feed stream as in 2g.,what is the mass flowrate of 1-3propanediol in the product stream?
A process for the microbial synthesis of 1,3-propanediol ( 3 8 2 C H O ) uses an anaerobic
fermenter with a selected strain of K. pneumoniae to convert glycerol ( 3 8 3 C H O ) to 1,3-
propanediol and acetic acid ( 2 4 2 C H O ). All other byproducts are of negligible concentration.
The fermentation and cell growth equation can be written:
3 8 3 3 4 7 2 3 8 2 2 4 2 2 2 68 3 3 49 15 15 40 C H O NH C H O N C H O C H O CO H O + → + + + +
The continuous fermentation process is set up at 37°C and atmospheric pressure.
Anaerobic conditions are maintained by sparging the fermentation broth with N2 at a
flowrate of 500 litres per minute. The medium, containing ammonia, is fed at 500 kg per
hour, and has a composition of 14% (w/w) glycerol. Suppression of the side reactions is
achieved by excess glycerol, so the liquid product contains 3% (w/w) unreacted glycerol.
2a. Draw a process diagram. List all your assumptions necessary to write a material
balance.
(5 marks)
2b. List your unknowns.
(3 marks)
2c. Write an overall materials balances for the mass flow rates of the liquid streams and the
gas streams separately. Make assumptions about which terms are negligible. Write a mass
balance for glycerol.
(3 marks)
2d. Compute the molar rate of glycerol consumption by K. pneumoniae in the fermenter.
The molecular weight of glycerol is 92 g mol-1
.
(3 marks)
2e. Compute the rate of CO2 gas rate evolution in litres per minute by the metabolism of
K. pneumoniae in the fermenter. Note that the molar volume of an ideal gas at 37°C is
25.24 litres.
(3 marks)
2f. Estimate the flowrate V and composition of the offgas stream.
(3 marks)
2g. What is the minimum concentration of ammonia needed in the medium?
(2 marks)
2h. If the ammonia concentration is the minimum required in the feed stream as in 2g.,
what is the mass flowrate of 1-3propanediol in the product stream?
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