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ChE513: Biochemical Engineering University of Santo Tomas Engr.

Achilles Espaldon

Submission Date: July 4, 2012 Group Members: ______________________ ______________________ ______________________ ______________________ ______________________

Assignment # 3 (for all sections) 1. A batch fermentation producing hybridoma cells generated the following data below; t, hr 0 1 2 3 4 5 5.5 6 7 8 a. b. c. d. e. X, g/L 0.18 0.19 0.2 0.25 0.68 1.8 3 5 5.2 5.3 S, g/L 10 9.9 9.8 9.7 8.8 6.5 4.1 0.2 0.01 0

Determine the maximum specific growth rate. Calculate the doubling time. Calculate the yield coefficient. Estimate the Ks. Take note of your assumptions. How long is the Lag phase? How long is the Growth phase? What is the total reaction time if we are going to run this in a batch reactor?

2. A facultatively anaerobic organism causes the following reaction to occur under anaerobic conditions: C6H12O6 -------------------- 2 C2H6O + 2 CO2 The fermentation is conducted in a mineral salts medium with the following partial composition (g/l): Medium formulation Glucose NH4Cl KH2PO4 MgSO4 g/L 20 2.5 0.25 0.1

All other required elements are present in excess. The facultative anaerobe has the following partial elemental composition (% dry weight basis): C = 50; N = 10; P = 4; S = 1.

Under anaerobic conditions, the cell yield on glucose is 0.1 g cell/g glucose. Under aerobic conditions, the cell yield is 0.4 g cells/g glucose. You may neglect glucose consumption for cell maintenance. a. Under anaerobic conditions, how much cell mass and ethanol will be produced per liter of fermentation broth? b. Under aerobic conditions, what will be the maximum cell concentration and residual glucose concentration? Be sure to note your major assumptions.

3. You are asked to develop a new product of a low calorie, high alcohol beer somewhat similar in specification to a leading brand, San Mig Light. You have a current product run at 10 m3 reactor volume with fermentation data below which you need to use for development with total reaction time of 100 hours. Assume that your substrate is a carbohydrate from the grains/ sugars used for brewing. Assume K s = 1.0 g/L, um = 0.4 hr-1 , KP = 7 g/L and YP / S = 1 . a. From the current product, calculate the carbohydrate content in grams per 350 mL bottle serving and alcohol content in %v/v. b. Plot the concentrations of X, S and P vs. time (in one graph only) c. Calculate the growth rate at 0, 24 and 70 hours. d. For the new product, calculate the volume of alcohol (L) needed to distill off to achieve a desired product with reduced carbohydrate content of 2.45 g per 350 mL bottle serving e. Calculate your total alcohol content in % v/v when the distilled alcohol is sent back to the fermentation solution. t, hr 0 1 5 12 24 40 70 100 X,g/L 0.03 0.50 2.20 5.30 10.40 16.30 11.40 1.20x10-4 S, g/L 50.00 49.40 47.09 43.29 37.49 30.94 21.59 15.06 P, g/L 0.00 0.60 2.91 6.71 12.51 19.06 28.41 34.94

"I pledge on my honour that as the group representative, I have honestly accomplished this homework and assignment only with the help of my groupmates and that sharing our solutions, answers and ideas to other groups violates the principle of independent thinking and working which constitutes our core integrity as students of ChE513 Biochemical Engineering. I believe that doing my best effort with the right mindset and attitude will fulfill my highest ideals as a student of this university."

____________________________________ Signature of group representative
