The Yeast Cell Factory - A Discovery Experiment
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Yeast is traditionally known for its use in the production of bread and alcohol however, this versatile microorganism is capable of much more.
Yeast cells can be thought of as mini factories. When fed with nutrients, such as sugar, and programmed in a certain way, they produce valuable products in return.
Researchers in the EU-funded project CHASSY are finding innovative ways of using yeast in new methods of production that are more sustainable and less environmentally damaging than current methods.
In this video, CHASSY researcher Noemi Montini demonstrates the transformative power of yeast through a discovery experiment.
What You’ll Need:
• 2 100 cm3 graduated cylinders
• 4 100 cm3 beakers
• 1 500 cm3 beaker
• 2 separating funnels
• 3 glass rods
• 3 thermometers
• 2 retort stands
• an electronic balance
• weigh boats
• a syringe (20 cm3)
• a timer
• a sachet of yeast (without calcium sulphate - CaSO4)
• sodium alginate
• calcium chloride powder
• sucrose, distilled water
• glucose test strips
• hot water (30 °C – 40 °C)
Step by Step Instructions:
To begin, add 0.4 g of sodium alginate to 10 cm3 of distilled water in a 100 cm3 beaker and mix thoroughly.
Mix 2 g of yeast in 10 cm3 of distilled water in a 100 cm3 beaker.
Prepare 100 cm3 of a 1.4% w/v calcium chloride solution in the large beaker by dissolving 1.4g of calcium chloride in 100 cm3 of distilled water.
Add the yeast suspension to the sodium alginate solution and mix thoroughly with a glass rod.
Draw up all of the mixture into a 20 cm3 syringe.
From a height of 10 cm, release the mixture from the syringe, one drop at a time, into the calcium chloride solution.
Notice how beads containing yeast cells are forming.
Leave the beads to harden for at least 10 minutes.
Filter the beads through a sieve and rinse with distilled water.
Mix another 2 g of yeast in 10 cm3 of distilled water.
Pour this yeast suspension into a separating funnel labelled ‘Free yeast’.
Pour the beads into another separating funnel labelled ‘Immobilised yeast’.
Prepare 100 cm3 of 1% w/v sucrose solution by dissolving 1 g of sucrose in 100 cm3 of distilled water warmed to about 40 °C.
Pour 50 cm3 of the sucrose solution into the yeast in each of the separating funnels.
Using glucose test strips, immediately test samples from each funnel for glucose.
Repeat the test at two-minute intervals until glucose appears in both and record results.
Run off the remaining product from each funnel into the beakers.
Results:
It takes longer for glucose to be produced by the immobilised cells. Why do you think this is?
Answer:
The sucrose needs to enter the pores in the alginate beads for the enzymatic conversion to take place.
The benefits of using the immobilised yeast however are that you get a purer product, the enzyme is stabilised and the enzyme can also be reused. These benefits are important when using yeast in large scale production.
For more information about the CHASSY project, you can visit: www.chassy.eu
Cork Discovers is proudly brought to you by UCC Academy, University College Cork, Teagasc, Cork City Council, CIT Blackrock Castle Observatory and British Council with special thanks to our media partners 96FM and Irish Examiner. This project has received funding the European Union's Horizon 2020 Research and Innovation Programme under grant agreement no. 955330
