Converting Cellulosic Biomass to Ethanol

Contributor
Massachusetts Institute of Technology (MIT) Department of Biology
Type Category
Instructional Materials
Types
Instructor Guide/Manual , Experiment/Lab Activity
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

This review focuses on the Sugar Fermentation lab resources contributed by MIT (see Vernier Manuals and Lab Extensions section for links to the lab activities and teacher guide at http://goo.gl/q5HkWn). The Sugar Fermentation Lab utilizes gas pressure sensors (or alternatively a balloon setup) for students to collect fermentation rate data for different sugars (glucose, fructose, and galactose). Students compare the results from the different sugars and propose explanations for why the rates differ. The lab then leads to further exploration of other carbohydrate sources to connect the lab to understanding the processes and challenges associated with converting cellulosic biomass to ethanol. The lesson sequence was designed by the Biology Department at the Massachusetts Institute of Technology (MIT) to provide an opportunity for students to connect learning about metabolic processes and molecular structure while exploring the process of creating cellulosic ethanol. The lesson is part of a sequence from the Great Lakes Bioenergy Resource Center (GLBRC), which primarily focuses on experiments comparing biomass sources. The addition of the Sugar Fermentation lab to the lesson sequence makes the set of resources especially relevant for units in chemistry. The other resources included by MIT and GLBRC in this collection of lessons should be used to provide a rich, relevant context for this lesson.

Intended Audience

Educator and learner
Educational Level
  • Grade 12
  • Grade 11
  • Grade 10
  • Grade 9
  • High School
Language
English
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

HS-PS2-6 Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.

Clarification Statement: Emphasis is on the attractive and repulsive forces that determine the functioning of the material. Examples could include why electrically conductive materials are often made of metal, flexible but durable materials are made up of long chained molecules, and pharmaceuticals are designed to interact with specific receptors.

Assessment Boundary: Assessment is limited to provided molecular structures of specific designed materials.

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation
Question #2 after the data analysis section in the lab handout asks students to hypothesize why galactose is not metabolized by yeast in the experiment while glucose and fructose are. This question provides an opportunity for students to begin considering how the molecular-level structure of sugars is important to their properties. The series of lessons that includes the lab activity will provide substantial opportunity for students to engage in many practices.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
The student handout includes detailed directions for using Vernier’s Logger Pro software to process the data and determine fermentation rates for each sugar in ppm/min. Then, students answer questions, using the results of the lab as evidence to support their claims. Teachers can consider modifying the lab sheet and asking students to determine ways to analyze the data in a way that results from the different sugars can be compared. Besides fermentation rate, students may consider total gas produced or compare methods for testing the ethanol content of the resulting solutions. Students could then build consensus as a class through argumentation about the best method for analyzing the data and/or the meaning of patterns in the data.

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
While discussing lab question #2 about why the data from the three test sugars (glucose, galactose, and fructose), students may suggest other reasons for the differences. Teachers should provide opportunities following the discussion to further explore all plausible explanations, including an opportunity for students to examine molecular models of the sugars that were tested.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
The questions posed in the lab ask students to consider cause and effect relationships as they suggest reasons for the difference in fermentation rates for different sugars. The cause and effect relationship is further extended when the results of this lab are connected to the larger context of producing ethanol from cellulose found in different feedstocks. The additional resources from GLBRC linked from the MIT page provides suggestions for how to connect this lab experience to the production of cellulosic ethanol.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This resource is an opportunity for students to collect data that they then use to propose an explanation about why sugars are utilized by yeast differently. When used within a lesson sequence about converting cellulosic biomass to ethanol in a similar as proposed by the MIT and GLBRC resources, this might be rated as a superior quality resource. To bring the resource to that level of learning, attention needs to be paid to supporting three-dimensional learning throughout the unit by providing more explicit opportunities for students to develop and use specific elements of the disciplinary core ideas to make sense of phenomena.

  • Instructional Supports: Good guidance is provided for the collection and analysis of data to help guide students to develop a deeper understanding of the practice of analyzing and interpreting data. However, teachers will need to consider how to provide differentiated support for all learners through opportunities for students to represent their ideas and respond to peer and teacher feedback in their written explanations for why the fermentation rates of the sugars differ. The instructor resource provides only minimal guidance for this in the “Communicating the Results” section. A discussion of results should include opportunities for each group to present their data and initial explanations with critique from other students to reach further consensus of connecting data to the molecular structure of various sugars.

  • Monitoring Student Progress: Teacher should consider formative assessment strategies for monitoring student progress throughout instruction, including during the experiment. This may include holding short conferences with each group, posing questions such as “what patterns do you notice in the data?” or “what does your data mean?” and then following with further probing questions to uncover students’ thinking. The conferences provide an opportunity for the students to prepare to communicate their results and provides the teacher with data to use in planning appropriate ways to support students in practices of data analysis and constructing explanations in ways that connect to the disciplinary core ideas and crosscutting concepts.

  • Quality of Technological Interactivity: This review pertains to the written lab activity and not the technology aspects of data collection and analysis during the activity.