Comparing feedstocks for fermentation

FTW Alumni educator Jeff Jostpille’s biology students used the Engineering Design process to investigate the production of industrial ethanol with the Corn Fermentation in a Bag experiment. They tested the process of fermentation using resealable bags with yeast, warm water, various feedstocks and enzymes.

Jostpille gave students feedstocks such as agave, coconut sugar, corn starch, stevia, and honey to use in their experiments. The students then measured the changes in plastic bags due to fermentation of the feedstocks with breathalyzers and bag inflation.

The students discovered that the relationship of the amount of CO2 to the level of alcohol found with the breathalyzer was equal. They also found that the variety of enzymes that they could use along with the yeast should have been specific to the type of carbohydrate they had in their bags—if they used a starch like the corn starch, they needed both amylase and glucoamylase in order for it to have the monosaccharides (simple sugars) that the yeast needed in order to make the alcohol.

Try this lesson in your class and see what YOUR students discover!