Corn is a vital part of our society. It has many uses, such as feeding people and producing ethanol. This lab can be used in two different ways. It can be used as a stand-alone lab if you do not have the time or resources to conduct a full ethanol distillation lab. However, you can also use this lab to enhance the Ethanol- Corn Mash and Distillation and to observe the different levels of nutrient availability before fermentation, after fermentation, and again after distillation. We will focus on what is happening to the nutrients, along with discussing macromolecules and the importance they provide to organisms.
The first part of the lab is creating a corn mash that will ferment and form methanol and ethanol. Discussions about ethanol can begin here. The main focus will be on what the yeast is doing to the corn, as well as the purpose of the enzymes that are present in the corn mash. The next part of the lab will be to compare the nutrient availability with a corn slurry (this can be made at the start of the second lab day), and the corn mash. This lab focuses on the liquid feed. Lugol’s Iodine provides a black color change when present in starch. The Buiret Test Solution provides a purple color change when present in protein. The last indicator provides an orangish-red color change when heated and present with glucose. These changes provide an important laboratory practice in observations.
Students who demonstrate understanding can
All glassware has a possibility of breaking. Protective eyewear should be worn at all times. The indicators being used can cause skin irritations and have the possibility of staining clothes.
Biuret Reagent, Lugol’s Solution, and Benedict’s Solution are all possible skin irritants. Please review all Safety Data Sheets for reagents used in lab for further safety information.
Note: The following procedures are what you will use if you are doing this as a stand-alone lab. You will need to make up the mash and slurry prior to starting the lab. You also have the option to perform this lab as part of the sequence in ethanol distillation. Kansas Corn: Ethanol – Corn Mash and Distillation (available online at kscorn.com) is the recommended unit to perform first in the sequence. The DDG Nutrient Test can be done before and after fermentation, as well as after distillation is complete, to compare the levels of nutrients in the different stages of production.
Preparation of yeast solution (1-2 hours before the lab)
Preparation of Enzymes (Prepare before the start of the lab)
Prescribed preparation of corn mash
Corn Slurry Preparation and Workstation Set-up.
In the United States, commercial production of fuel ethanol involves breaking down the starch present in corn into simple sugars, also called “glucose”. These sugars are than fed to yeast, which begins the process of fermentation. The main product is used as ethanol – it is primarily found as a fuel additive in the gasoline used in our vehicles. The ethanol industry utilizes many different parts of the production process. Some of the other products produced include animal feed, corn oil, and carbon dioxide. The product used in animal feed is known as distillers grains. There are two types of these grains – wet distillers grains and dry distillers grains. Wet distillers grains have a high water content and low shelf life. This results in transportation to local farmers near the ethanol plant for use in feed for livestock. Dry distillers grains have been dried to have a low water content. They have a longer shelf life and can provide feed for farmers at locations further away.
Introduce the topic and assess students for prior understanding. Let students discuss their ideas, and guide the discussion without telling them if they are right or wrong.
Making Fermented Corn Mash and Forming Predictions:
Have the students answer the following questions on the DDG Student Lab Report Sheet:
Students should have made observations about the results they found in the test. Students should be able to identify where these distillers grains are produced and the importance it has for the ethanol industry. The following include some sample questions to pose for the students after the tests are completed:
Students should understand that the production of ethanol not only makes ethanol that we use in gasoline, but it also provides farmers with resources to help cattle and other livestock grow by using distillers grains as a food source.
To wrap-up this topic, students can research some of the following careers. Students can find out what role each of the careers plays in studying nutrients and their functions in agriculture. Students can complete this part of the write up on the DDG Student Lab Report Sheet.
Soil and Plant Scientist
Any educator electing to perform demonstrations is expected to follow NSTA Minimum Safety Practices and Regulations for Demonstrations, Experiments, and Workshops, which are available at http://static.nsta.org/pdfs/MinimumSafetyPracticesAndRegulations.pdf, as well as all school policies and rules and all state and federal laws, regulations, codes and professional standards. Educators are responsible for abiding appropriate legal standards and better professional practices under a duty of care to make laboratories and demonstrations in and out of the classroom as safe as possible. If in doubt, do not perform the demonstrations.
Investing in teachers is a priority therefore the Kansas Corn Commission is committed to providing free materials and training to help teachers excel in the classroom. Distillation kits and funding for ethanol plant tours are available to teachers who teach Kansas Corn’s ethanol labs. Teachers who seek to expand their knowledge and skill of these labs are encouraged to seek out a training opportunity.