CenUSA Bioenergy High School CurriculumJuly, 2015
CenUSA Bioenergy High School Curriculum
July, 2015
Lesson 5: Fermentation
This lesson covers the fermentation process. Student will need this knowledge to complete labs and research in following lessons. Lessons are designed for 10th-12th grade students. This lesson was designed for a block schedule; however, it may be shortened and edited to suit the teacher, the material, and the class. This material may also be used in other agricultural classes.
Learning Objectives
At the end of this lesson, students will be able to successfully achieve the following objectives:
- Define fermentation and the basic steps involved in the process.
- Describe how fermentation is used in biofuel production.
- Rankdifferent fermentation feedstocks based upon their fermentation potential.
Academic Standards
Domain:Biomass Systems
Core Standard 5:Students evaluate various aspects of biomass systems as alternative energy resources.
Indiana State Standard:SEA-5.1, 5.2, 5.5, 5.6, 5.9
National AFNR Standards:CS.02.04; CS.03.03; BS.01; BS.02
Next Generation Science Standards:HS-PS3-3, HS-ESS2-6, HS-ESS2-7
Documentation of Competencies Met by This Lesson
Connection to SAE/Career Development: Agriscience Research - Plant Systems, Emerging Agricultural Technology, Food Science and Technology
Connection to FFA/Leadership Development/Personal Growth: Anything that involves working with new and emerging technology, fermentation, or continuing education.
Note. The content for this lesson was originally created by Craig A. Kohn of Waterford Union High School, Waterford, WI. It is used and reprinted with his permission.
For more information and other activities, please visit his website at:.
Orvis, Kararo, Long ©PurduePage 1August 2014
CenUSA Bioenergy High School CurriculumJuly, 2015
Curriculum Content Included
Websites Utilized
Supplies Needed
Teaching Content and Learning Activities
5.1 Introduction to Fermentation
Learning Activity
Teaching Content
Learning Activity
Teaching Content
5.2 Ethanol
Teaching Content
5.3 Cellulose
Teaching Content
5.4 Ruminant Fermentation
Teaching Content
5.5 Lab: Biofuels and Fermentation
Description
Background Information
Learning Objective
Time Requirement
Supplies
Warnings
Directions
5.6 Ethanol Fermentation Jeopardy
Learning Activity
Lesson 5: Student Review Questions
Lesson 5: Student Review Questions - KEY
Lesson 5: Teacher Assessment
Supplemental Documents:
Lesson 5 PowerPoint Presentation
Lesson 5 Print Outs
Lesson 5 Ethanol Jeopardy PowerPoint Game
Websites Utilized
- Craig A. Kohn on May 24, 2011;
Supplies Needed
Orvis, Kararo, Long ©PurduePage 1August 2014
CenUSA Bioenergy High School CurriculumJuly, 2015
•Balloons
•Yeast
•Sugar
•Warm Water
•Corn kernels
•Table sugar
•Soybeans
•Fruit
•Potato
•Corn husks
•20 oz. soda bottles
•Yeast
•Hydrometer
•Calculators
•Balloons
•Scale
•Weigh boats
•Gloves
•Small scoops
•Mortar and pestle
Orvis, Kararo, Long ©PurduePage 1August 2014
CenUSA Bioenergy High School CurriculumJuly, 2015
Teaching Content and Learning Activities
Notes.
A PowerPoint presentation is included with this curriculum and includes the follow teaching content and learning activities. You may modify the presentation as needed for your class.
The teaching content and learning activities are presented here in the suggested order of occurrence.
5.1Introduction to Fermentation
Learning Activity
Have students consider what they think about when they hear the word fermentation. After they have thought about it for a short time, have them write down on a piece of paper what different types of things are needed for fermentation to happen. Allow them two to three minutes to complete this. Have volunteers share with the class what they wrote on their paper.
Teaching Content
The process of fermentation is critical for the production of products such as:
•Ethanol
•Bread (yeast causes the bread to rise)
•Alcoholic beverages
•Yogurt and cheese (bacteria produce lactic acid which with rennet curdles the milk)
•Pickles and sauerkraut
Additionally, fermentation is necessary for ruminants, such as cattle, to break down cellulosic vegetation.
What is Fermentation?
Fermentation is a form of cellular respiration done in an environment without oxygen (anaerobic). Respiration is the complete breakdown of a source of energy such as a sugar into CO2 and H2O in an aerobic environment.
Yeast and bacteria are frequently used as fermenters. They consume sugars for energy and release byproducts such as ethanol and carbon dioxide.
Fermentation is the process by which we create ethanol from renewable plant materials. This is very different from transesterification, the process by which we create biodiesel. Transesterification is a chemical process; fermentation is a biological process.
Learning Activity
Supplies
•Balloons
•Yeast
•Sugar
•Warm Water
Directions
- Have students fill a balloon with a tsp of yeast, a tsp of sugar, and a Tbs of warm water.
- Have them tie off the balloon and shake the mixture together.
- Allow the balloons to sit as you teach this lesson. A time passes, the balloons will start expanding.
Discussion
Have students answer the following questions:
- What is yeast?
- How did sugar and warm water contribute to this experiment?
Have students connect back to the lesson and how yeast contributes to fermentation and biofuels.
Teaching Content
Fermentation consists of substrates and products. Substrates are the substances being acted upon (usually a sugar) and products are the substances created (ethanol, lactic acid, etc.). Ethanol is a waste product for the organism because it cannot acquire any additional energy from this molecule.
Fermentation requires an organism that can break down substrates in the absence of oxygen. For example, yeast (saccharomyces) is most often the organism of choice because they contain certain enzymes that can break down sugars. However, yeast is not the only organism that can do this. Many species of bacteria can also ferment.
5.2 Ethanol
Teaching Content
Ethanol from Starch and Cellulose
Ethanol production becomes more difficult when starting with corn grain or other more complex plant materials.The long sugar molecules in starches (like corn and potatoes) require additional steps to complete fermentation. The fermenting organism musthave enzymes that chop the long chains of starch into smaller glucose units.This is known as saccharification.
Corn Ethanol
Fermented corn is how the United States currently produces the majority of its ethanol that is used as a biofuel. It is generally either sold as 85% ethanol (E85) or blended with standard gasoline at a rate of 5-15% (E5-E15). Corn-based ethanol is made by using one of two processes: wet-milling or dry-milling.
In wet-milling, the corn is “steeped” (soaked in hot water) before it is processed any further. The steeping process helps release the starches contained within the kernel. Wet-milling is an industrial-scale flexible process that can create many byproducts from corn, but there is a high initial cost of equipment, so it is mostly used by large companies. From this point, there are a number of detailed processes that ultimately result in the production of gluten, oil, and starch. Gluten can be processed further into livestock feed, oils can be processed further into a variety of food products, and starches can be processed further into sugars and fermented by yeast into ethanol.
In the dry-milling process, the corn kernels are not steeped. Smaller farmer co-ops that focus on ethanol production usually use the dry-milling process due to its lower overhead costs. Instead of steeping the corn kernels, they are ground into a fine powder or flour before being added to water. The corn-water mixture is called a “mash.” Enzymes are then added to the mash that turn starch into sugars. Yeast is then added to the mash and fermentation takes place converting the sugar into ethanol. After fermentation is completed, the ethanol is removed and the remaining material is sold as “DDG” (dried distillers grains), which is a nutrient-rich livestock feed.
5.3 Cellulose
Teaching Content
Cellulose as a Feedstock
Cellulose is another possible feedstock for the fermentation method of creating ethanol. It has the potential to be the largest source of biofuel due to cellulose making up a majority of plant tissues, and being made up of complex sugar chains. So why are we not utilizing this resource right now since sugars are able to be fermented into ethanol? The answer lies in the differences between cellulose and starch.
Both starch and cellulose are polymers (chain of molecules) made up of glucose (sugar). In cellulose, the complex orientation of the molecules makes it stronger than starch, and more difficult to break down than simple starches. Additionally, cellulose is wrapped in lignin and hemicellulose, thus making the cellulose even more difficult to access. Besides the physical characteristics that make cellulose more difficult to break down into sugars than starch, there is also the issue of needing enzymes. Enzymes break down polymers into individual molecules, and there are many more known enzymes that can break down starch than can break down cellulose.
Today’s Work
Currently researchers in chemistry labs are attempting to find ways to make accessing cellulose easier and cheaper, which involves dealing with lignin and hemicellulose, the two complex polymers that surround cellulose and increase its strength. In addition to dealing with the physical barriers to accessing the cellulose polymers, scientists are also attempting to find more cellulose enzymes in order to reduce costs. This would address the chemical differences between starches and cellulose. In a future lesson, we will discuss how biologists are contributing to the cellulosic ethanol industry by selectively breeding plants for certain characteristics that make cellulose easier to access.
5.4 Ruminant Fermentation
Teaching Content
In many ways, what we want to accomplish in regards to fermentation of cellulosic ethanol is very similar to what the rumen (the first stomach) of a cow already does for the following reasons:
- A cow’s rumen is filled with microbes that produce cellulase, the enzyme that breaks down cellulose.
- A cow’s rumen is the perfect environment for these microbes to thrive.
- A cow’s rumen is a good model for what we want to be able to do with cellulosic feedstock for ethanol.
- The work of the rumen produces far more energy than it consumes.
The top benefit of being an herbivore is the ability to extract energy from cellulose in plant cell walls. Cellulose makes up about half of the dry weight of stems, roots, and leaves. A cow can meet almost all of its dietary needs from the vegetation that surrounds it in a pasture. Few animals are better equipped to obtain large amounts of energy from cellulose.
We would like to do the same, but for fuel.
Think about what a cow must do to break down cellulose:
- Obtain the food (graze).
- Grind the food to increase the surface area (chew).
- Chemically break down the food (with enzymes in the saliva such as amylase). This would be known in chemistry as hydrolysis. Hydrolysis is a reaction with water that breaks larger molecules into smaller ones (e.g. example breaking cellulose into glucose).
- Ferment the food in their rumen with microbes
- Absorb and digest the carbohydrates in their stomachs and intestines
The steps in making cellulosic ethanol are very similar.
5.5 Lab: Biofuels and Fermentation
Modified from:
Biofuels. (2015). Retrieved August 26, 2015, from
Valenti, C., King, K., & Yowell, J. (2009). Corn for Fuel? Retrieved August 26, 2015, from
Description
This lab will provide students with a more in-depth understanding of fermentation.Students will design an experiment to compare the amount of ethanol produced by the fermentation of various organic materials such as corn, grass, and fruits. Students will then research the pros and cons of growing and processing these materials for use as biofuels. Finally, students will use the information from the experiment and research to design a bio-refinery plant.
Background Information
Have students watch the video How Ethanol is Made to review and visualize fermentation. The video can be accessed here:
Learning Objective
Upon completion of this lab, students will be able to:
•Differentiate between efficiencies of fermentation “feedstocks”.
•Design a bio-refinery plant.
Time Requirement
Approximately 20-30 minutes; entire process takes multiple days.
Supplies
Orvis, Kararo, Long ©PurduePage 1August 2014
CenUSA Bioenergy High School CurriculumJuly, 2015
- Corn kernels
- Table sugar
- Soybeans
- Fruit
- Potato
- Corn husks
- 20 oz. soda bottles
- Yeast
- Hydrometer
- Calculators
- Balloons
- Scale
- Weigh boats
- Gloves
- Small scoops
- Mortar and pestle
Orvis, Kararo, Long ©PurduePage 1August 2014
CenUSA Bioenergy High School CurriculumJuly, 2015
Warnings
- Students should wear gloves and goggles at all times.
- Experiments should be conducted in a well-ventilated area.
- While the amount of ethanol produced is minimal and very diluted and thus not highly flammable, the ethanol should be disposed of properly and carefully. Check your state regulations on proper disposal.
Directions
Split the students into groups of 4. As a group, have the students select 3-4 types of biomass they want to test.
- Have students prepare a different soda bottle for each biomass sample, including a control bottle.Make sure the bottles are labeled with the type of biomass going inside.
- Students should measure out 2 grams of yeast for each bottle using the weigh boats and scales.
- All biomass should now be broken up in whatever way is proper (e.g. using the mortar and pestle). In lieu of breaking it up themselves, students can be provided with samples that do not need breaking up (e.g. sugar or corn meal).
- 10-20 grams of biomass from each sample should be placed in each appropriate bottle. Samples sizes can be within the range of 10-20 grams, but make sure students take care and place the same amount of each material in each bottle.
- For each bottle, students should fill a balloon with warm (but not too hot) water to the point where the balloon begins to expand (do not overfill balloons). Have students then fit the balloons to the top of the bottles, creating a seal. The water in the balloons can then be released into the bottles.
- Bottles should be slightly agitated to mix all ingredients and then placed in a warm location (conditions should be as similar as possible for all bottles).
- Fermentation will begin to occur, but may take several days to complete. Observations and measurements should be taken each day (e.g. visual composition of mixtures, balloon circumferences, etc. adapt as needed). How much are the balloons expanding? What do the mixtures in the bottles look like? Were there any unforeseen variables that need to be taken into account?
- On the days where the class is waiting for fermentation to complete, have students research each of the biomass material they used in their bottles. What is needed for each to grow? How much land is needed to grow each type of biomass? How long does it take for each type of biomass to grow to a size useful for bioenergy purposes? How much fertilizer is needed? What type of pre-fermentation processing is needed? Which biomass sources elicit a food vs. fuel debate?
- After the measurements of balloon circumferences are unchanged on two consecutive days, have students make final observations of all previously defined variables for each bottle. Discuss how the balloon circumference is a proxy for level of ethanol production due to the fermentation process.
- Students should then as small groups compare the relative ethanol production of their different biomass materials. Using their data and the research they conducted, each group should be assigned an area of the state (or entire state, or country) for which they need to design a biomass ethanol production facility. Groups should prepare a presentation covering variables involved in their decision-making process (e.g. initial production startup costs, fossil fuels needed for production, production efficiency, food vs. fuel debate, plant location, etc.).
- Final presentation should be to the entire class and include detailed data for their plant construction. Presentations should be as if the groups are presenting to an investment group that could fund plant construction.
Lesson 5: Student Review Questions
Name: ______Date: ______
Select T/F for the questions listed below:
1. ______Fermentation: a form of cellular respiration done in an environment without oxygen (anaerobic)
2. ______In many ways, what we want to accomplish in regards to fermentation of cellulosic ethanol is very similar to what the rumen (the first stomach) of a cow already does.
3. ______There are two methods used to convert the corn kernel into a usable fuel: wet milling and dry milling
4. ______Yeast (saccharomyces) is most often the bacteria of choice.
5. ______Pretreatment is currently the least expensive part of the conversion process.
Lesson 5: Student Review Questions - KEY
Name: ___ MASTER KEY______Date: ______
Select T/F for the questions listed below:
1. _____T_____ Fermentation: a form of cellular respiration done in an environment without oxygen (anaerobic)
2. _____T_____ In many ways, what we want to accomplish in regards to fermentation of cellulosic ethanol is very similar to what the rumen (the first stomach) of a cow already does.
3. _____T_____ There are two methods used to convert the corn kernel into a usable fuel: wet milling and dry milling
4. _____F_____ Yeast (saccharomyces) is most often the bacteria of choice.
5. _____F_____ Pretreatment is currently theleast expensive part of the conversion process.
Lesson 5: Teacher Assessment
As the teacher, reflect on the Lesson 5 and answer the following questions.
- What did the students like about this lesson?
- What did the students dislike about this lesson?
- Did the students find anything difficult in this lesson? If so, what?
- What are the strengths of this lesson?
- What are the weaknesses of this lesson?
- What went well during this lesson?
- What did you find difficult or challenging during this lesson?
- Where the objectives met effectively during this lesson?
- Were the labs or activities relevant to the lesson topic?
- Overall, do you have any other suggestions or thoughts about this lesson?