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

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

Overview

The previous lesson 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. This lesson 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.

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.

Questions?

If there is anything in the lesson materials that you would like to comment on, or don't quite understand, please post your thoughts and/or questions to our Throughout the Course Questions & Comments discussion forum and/or set up an appointment for office hour. While you are there, feel free to post responses to your classmates if you are able to help.