6. What is the pH of the medium when sucrose is used as a substrate for the production of citric acid?
A. 3
B. 4
C. 5
D. 6
7. In the liquid surface culture process for the fermentation to produce citric acid,
A. A. niger is used with the solid substrate as sweet potato
B. A. niger floats on the surface of the solution
C. Fungal mycelium grows throughout the solution in a deep tank
D. both (a) and (b)
8. In the koji process for the fermentation to produce citric acid,
A. A. niger is used with the solid substrate as sweet potato
B. A. niger floats on the surface of the solution
C. Fungal mycelium grows throughout the solution in a deep tank
D. both (a) and (b)
9. What is the pH of the medium when molasses is used as a substrate for the production of citric acid?
A. 3
B. 4
C. 5
D. 6
10. Which of the following nitrogen sources is added in the fermentation medium of citric acid production?
A. Ammonium salt
B. Urea
C. Both (a) and (b)
D. Peptone