Question

3.11. The growth of baker's yeast (S. cerevisiae) on glucose may be described simply by the following equation: CH 206 +302 +0.48NH7+0.48C4HNO3 (yeast) +4.32H 0+3.12CO, In a batch reactor of volume 105 L, the final desired yeast concentration is 50 g/L. Using the preceding reaction stoichiometry: (a) Determine the concentration and total amount of glucose and (NH4)2SO4 in the medium. (b) Determine the yield factors YFX/s (biomass/glucose) and YFxo, (biomass/ oxygen). (c) Determine the total amount of oxygen required. (d) If the rate of growth at exponential phase is rx =0.7 g/(L h), determine the rate of oxygen consumption at g-02/(L h). (e) Calculate the heat-removal requirements for the reactor.

Answer 1

Given Ron is - Co Hig On + 39 to 48 NH3 0.48 C6H, NO₂ + 4.324.0 Yeast) +3 12 co Noboda Cycast total los L. = Sog/L ( vom of ( Come of Reactor). yeast). yeast = losx 50 g = 5250 g. total moles of yeast = 5250- M.wt of yeast Mint of yeast = 6x12 + 10x1 + 1 x 24+ 3x16 _=144 glmali tolal moles of yeast = 5250 moles a = 36.46 moles By stoichiometry of Ren - Moles of glucose Req = 36.46. ~ 76 moles 0.48 Man of glucose hea i 180x 76. - 13680g = 13.68 kq. Concentration of glucose = 12680. - 130.3g/4 los

Moles of NH₃ hea tormed. moles of yeast = 36.46 moles 1 mole of W/44)₂ Sou gives 2 moles of NH (alla), so → 2NH3 + H₂SO4 Moles of (144), SO4 Req = Moles of NH3 36:48 - 18.23 moles Mint of (N1442504 = 132 g/mol. Man of W Hada Sou reqa 18.23x132 - 24069 2.406 ke Conc. of (alkala so = 2.406 x 10 105 22.91 g/L glucose - g of yeast formed second 3 5250 13680 0.384. g broman g glucose Y biomom ortun g of yeast toomd go on raj.

Man of On rea= 3. x moles of yeast 832 7292 g Y bioman = 5250 7292 = 0 72 g bioman 9 O2 ey total amte of Os rea = 72.92 g. 7.292 kg from stoichiometry of renal 48 -roz a 3 x -oz (mal) = 6.25 Nyest ryeast (mol/L.hr.). -roz ( a 2 = 6:25 x 144. syeast ( 9/1 hne - 2 8 12s (geant ( 8 ) L.hr 32