Nicotiana tabacum cells are cultured to produce a polysaccharide gum. The reactor used is a stirred-tank reactor with an initial volume of 100 L. The maximum specific rate of growth of the culture is 0.18 d-1 and the yield coefficient of substrate in biomass is 0.5 gX/gS. The concentration of the limiting substrate in the medium is 3% (m/v). The reactor is inoculated with 1.5 g/L of cells and operated in batch until the substrate is exhausted, when the medium is fed with a constant flow rate of 8 L/d. The fed batch occurs in a quasi-steady state condition. a) Estimate the time of the batch step and the concentration of cells reached in this phase, considering exponential cell growth. b) The fed batch phase is carried out for a period of 40 days. What is the final concentration of cells in the reactor? c) The bioreactor is available for the process for 275 days a year, with an interval of 24 hours between each cultivation. What is the most advantageous operating mode for the process (annually): single batch or fed batch? (answers: a) t = 13.3 days (14 days); X = 16.5 g/Lb) X = 15.4 g/L c) fed batch)
Nicotiana tabacum cells are cultured to produce a polysaccharide gum. The reactor used is a stirred-tank reactor with an initial volume of 100 L. The maximum specific rate of growth of the culture is 0.18 d-1 and the yield coefficient of substrate in biomass is 0.5 gX/gS. The concentration of the limiting substrate in the medium is 3% (m/v). The reactor is inoculated with 1.5 g/L of cells and operated in batch until the substrate is exhausted, when the medium is fed with a constant flow rate of 8 L/d. The fed batch occurs in a quasi-steady state condition.
a) Estimate the time of the batch step and the concentration of cells reached in this phase, considering exponential cell growth.
b) The fed batch phase is carried out for a period of 40 days. What is the final concentration of cells in the reactor?
c) The bioreactor is available for the process for 275 days a year, with an interval of 24 hours between each cultivation. What is the most advantageous operating mode for the process (annually):
single batch or fed batch?
(answers: a) t = 13.3 days (14 days); X = 16.5 g/Lb) X = 15.4 g/L c) fed batch)
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