TLS Online TPP Program

#Question id: 14244


Ethanol is produced by anaerobic fermentation of glucose by Saccharomyces cerevisiae. For the particular strain of S. cerevisiae employed, the maintenance coefficient is 0.18 kg kg- 1 h- 1, Yxs is 0.11 kg kg-1, YPX is 3.9 kg kg-1 and µmax is 0.4 h-1.  It is decided to investigate the possibility of using Zymomonas mobilis bacteria instead of yeast for making ethanol. Z. mobilis is known to produce ethanol under anaerobic conditions using a different metabolic pathway to that employed by yeast. Typical values of Yxs are lower than for yeast at about 0.06 kg kg-1; on the other hand, the maintenance coefficient is higher at 2.2 kg kg -1 h -1. Ypx for Z. mobilis is 7.7 kg kg-l; µmax is 0.3 h- 1.  From stoichiometry, what is the maximum theoretical yield of ethanol from glucose                 

#Section 5: Bioprocess Engineering and Process Biotechnology
  1. 0.51gg-1       
  2. 0.71gg-1    
  3. 0.61gg-1
  4. 0.91gg-1