Fermentation with Yeast

Recommended for grades 10–16.

Figure from experiment 11 from Investigating Biology through Inquiry

Introduction

Yeast can metabolize sugar in two ways, aerobically, with the aid of oxygen, or anaerobically, without oxygen. When yeast metabolizes a sugar under anaerobic conditions, ethanol (CH₃CH₂OH) and carbon dioxide (CO₂) gas are produced. An equation for the fermentation of the simple sugar glucose (C₆H₁₂O₆) is:

\text{C}_{6}\text{H}_{12}\text{O}_{6} \rightarrow \text{2 } \text{CH}_{3}\text{CH}_{2}\text{OH} + \text{2 } \text{CO}_{2} + \text{energy}

The metabolic activity of yeast can be determined by the measurement of gas pressure inside the fermentation vessel.

Objectives

In this Preliminary Activity, you will use a Gas Pressure Sensor to monitor the pressure inside a conical tube as yeast metabolizes glucose anaerobically. When data collection is complete, you will perform a linear fit on the resultant graph to determine the fermentation rate.

After completing the Preliminary Activity, you will first use reference sources to find out more about sugar fermentation by yeast before you choose and investigate a researchable question dealing with fermentation. Some topics to consider in your reference search are:

sugars
glucose
monosaccharides
disaccharides
fermentation
anaerobic respiration

aerobic respiration
yeast
enzyme
substrate
enzyme inhibitor

Sensors and Equipment

This investigation requires each of the following Vernier sensors and equipment (unless otherwise noted):

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

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Step-by-step instructions for the Preliminary Activity
List of materials and equipment

Note: The experiment preview of the Preliminary Activity does not include essential teacher information, safety tips, or sample data. Instructions for Logger Pro and other software (such as LabQuest App or TI handheld software, where available) are on the CD that accompanies the book. We strongly recommend that you purchase the book before performing experiments.

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Standards Correlations

No standards correlations for this experiment.