BIOCHEMICAL CONVERSION: BIOFUELS BY INDUSTRIAL FERMENTATION - Biomass as a Sustainable Energy Source for the Future - page 438

KEY CONCEPTS

Anaerobic fermentation
Yield on substrate
Enzymatic hydrolysis
Metabolic pathways
Cell growth and maintenance
ATP production
Biofuel energy content
Fermentable sugars
Product inhibition
Engineered or recombinant microorganisms

SHORT-ANSWER QUESTIONS

13.1 What crops are typically used as a feedstock for ethanol fermentation?

13.2 What are bagasse and vinasse?

13.3 What is the advantage of producing a liquid biofuel that is immiscible

with water?

13.4 Calculate the ethanol production per year from the data given in Table 13.3 or
13.5 on the basis of 167 days of operation per year (24 h per day).

13.5 What is a typical energy content of biofuel produced from a 1 kg glucose by
fermentation?

PROBLEMS

13.1 Combine Figures 13.2 − 13.7 in one drawing.

13.2 Does the material balance of Table 13.4 close?
13.3 Calculate the maximum theoretical yield of ethanol on sucrose in kg.kg -1 on
the basis of the reaction equations in 13.2.5 (molecular weights (g.mol -1 ):
sucrose, 342; ethanol, 46; CO 2 , 44), and compare to the actual yield according
to Table 13.4.

13.4 The material balance of Table 13.3 does not exactly close, seemingly a small
calculation error. But how many kg per day has an unknown source?

13.5 Check the fermentor volume calculation in Section 13.2.7 using Table 13.4.

13.6 Derive the 85,980,300 $ per year revenues of the first-generation
bioethanol process from the data given in 13.2.8 and the answer to short
question 13.4.