Eau That Smell Lab

Teacher Considerations

Eau That Smell Activity

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Quick Guide Eau That Smell

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In this lab, normally stinky smelling bacteria are made to smell sweet, like bananas. Four strains are compared for their banana smells. The activity provides a valuable opportunity to teach microbiology techniques, population growth dynamics, molecular genetics and basic synthetic biology concepts such as system design and transfer curves. The analysis of the lab's data will provide the students with a chance to do meaningful error analysis and examine the difference between quantitative results and qualitative results. Finally, this lab offers two protocols based on the time the teacher wishes to allow. Each of these protocols covers the same concepts but allows for different emphases.

Download poster for the lab

Download Quick Guide for the lab

Download Chapter 6: Eau that Smell, from the BioBuilder Textbook

Download Teacher's Lab Manual (color)

Alignment to Standards

Downloads that show how BioBuilder content can be used to meet the following teaching standards:

Sample Unit Plans

Some helpful background content and skills


  • DNA Basics: what it is and how it works
  • Gene Expression: Transcription, Translation, Operons
  • Recombinant DNA: Restriction enzymes, cloning, selection with antibiotic resistance


  • Pipetting
  • Measuring cell density with a spectrophotometer
  • Basic microbiology skills: Culturing bacteria, Aseptic technique, Antibiotic resistance, Population dynamics
Some lab materials to have on hand
  • HARDWARE: Some basic biology laboratory equipment such as glassware, pipets, a water bath or heat block to heat samples, an icebucket or styrofoam cup to cool samples, 4C fridge and ice-cold freezer (ideally to -20C) to store samples, a stir plate to mix samples, and an incubator to grow samples (though room temperature can work too). Some additional experiments might need a chemical hood, electrophoresis chambers, spectrophotometer, or a PCR machine.
  • CONSUMABLES: Some basic consumable laboratory equipment such as pipet tips, plastic tubes, growth media, petri dishes, toothpicks, spreaders, sterile loops, bleach or the like for decontamination and disposal of bioreagents. Some additional experiments might need additional consumables such as gel running buffers, loading buffers, stains to visualize DNA or proteins, cuvettes, PCR master mix, or an autoclave for sterilizing reagents.

BioBuilder Classroom

Here are some activity specific materials you can use in addition to the more general resources you'll find on the "Teacher Resources" page.


Download Chapter 6: Eau that Smell, from the BioBuilder Textbook

Download a Methods in Enzymology chapter describing this lab.

Download Teacher's Lab Manual (color)

Download Teacher's Lab Manual (B&W)


Download "Intro to SynBio" video lesson slides

Download "Eau d'coli" video lesson slides

Download iGEM team Jamboree presentation slides


Intro to SynBio Intro to Eau d'coli
MIT iGEM team presentation


Download Eau That Smell Poster

Download Poster

Quick Guide for Eau That Smell

Download Quick Guide

Eau That Smell

Download comic strip

BioBuilder Lab

Lab Materials

Download Student's Lab Manual (color)

Download Student's Lab Manual (B&W)

Download Quick Guide for the lab

Download Reagents List (Appendix) from the BioBuilder Textbook

Download packing list for the Eau That Smell lab

Lab Videos

Streaking Cells Overnight Cultures
Growth Curves


Download lab intro_v1

Download lab intro_v2

Other resources

Download workflow for Eau That Smell_protocol A

Download workflow for Eau That Smell_protocol B

Download helpful tips for running Eau That Smell lab

Analysis and Feedback

Lab Follow-ups

Can fruitflies be used to measure intensity of banana smell?

What is effect on smells if growing the cells at different temperatures?

If you are using the McFarland standard, would more precise or subtle standards be useful?

Rather than telling the students which strain is which, can they identify the strains based on their smell patterns?

Submit your data

Eau That Smell Sample Data

When the students have finished their experiments, ask them to upload their data to the BioBuilder site to see how their measurements compare to what other BioBuilders around the country have seen. Email BioBuilder for the passcode to enter the data sharing portal.

Assessment rubrics

Download sample rubrics to modify and use:

Lab Report Score Sheet for Eau That Smell

Lab Report Rubric for Eau That Smell