EGEE 439
Alternative Fuels from Biomass Sources

Lesson 7: Processing to Produce Ethanol and Butanol from Carbohydrates and Enzymes


Lesson 6 covered the final project, composition of various carbohydrates, and the enzymes necessary for conversion of cellulose (to glucose), hemicellulose, and lignin. That’s just the initial step for conversion of lignocellulosic biomass. Lesson 7 will cover the process necessary to convert starch into smaller units (like glucose) as well as the entire processing required to produce ethanol. Once glucose is produced, production of ethanol is the same, whether beginning with starch or cellulose. In a separate section, we will also discuss production of butanol (a four carbon chain alcohol) rather than ethanol (a two carbon chain alcohol); this will include why we might want to convert to butanol.

Lesson Objectives

By the end of this lesson, you should be able to:

  • explain similarities and differences between sugar-based and starch-based ethanol production as well as butanol production;
  • describe the differences between wet and dry milling of corn;
  • explain process steps in dry milling ethanol and butanol production;
  • identify important co-products from corn ethanol and butanol production;
  • evaluate the largest factors that affect economics of ethanol and butanol production.

Lesson 7 Road Map

This lesson will take us one week to complete. Please refer to the Course Syllabus for specific time frames and due dates. Specific directions for the assignment below can be found within this lesson.

Steps for Completing Lesson 7
Step Activity Access/Directions
1 Read Robison, D. (2012, March 19). Startup Converts Plastic To Oil, And Finds A Niche. Retrieved December 16, 2014. 7.5
2 Read Bourzac, K. (2009, July 9). Biofuel Plant Opens in Brazil. Retrieved December 16, 2014. 7.5
3 Discussion #7 7.5


If you have any questions, please send them to All Course Instructors through ANGEL e-mail. I will check daily to respond. If your question is one that is relevant to the entire class, I may respond to the entire class rather than individually.