Which 6 Carbon Sugar Would be Most Suitable for Yeast Fermentation by Energy Efficiency?

Introduction

Many yeasts are anaerobic organisms or can survive in oxygen – absent environments during which time they ”switch” to a process called anaerobic respiration for the purpose of producing food by breaking down carbohydrates. The final products of the anaerobic respiration are nutrients, ethanol and carbon – dioxyde. Whats more, different types of carbohydrates release various amounts of energy during fermentation. The amount of CO2 released is directly proportionate to the quantity of energy gained by the process.

Research question

Which 6 – carbon sugar would be most suitable for yeast fermentation by energy – efficiency?

Hypothesis

In our opinion, glucose posesses the highest energy potential, due to its structure and the locations of its OH groups.

Dependent

CO2 released

Controlled

Independent

Types of sugars used

Fixed

Temperature of bath water

Concentration of sugars

Quantity and type of yeast

Table of variables

Materials

* yeast suspension

* 2% of glucose, sorbose, fructose and galactose solution

* distilled water

* 12 x 10cm3 syringes

* 12 test tubes plus corks

* 250 ml beaker

* hot water at 40�C

* 10mL measuring cylinder

* distilled water

* stop water

* gloves

Method

1. Pour 5 cm3 yeast solution mixture into a test tube

2. Add 5 cm3 of fructose into the test tube

3. Shake the test tube to mix the solutions

4. Put the stopper with syringe into a test tube

5. Place the tube containing the syringe into the beaker with water bath at 40�C

6. Measure the CO2 for every 5 min

7. Repeat the procedure with the other solutions

8. Record the time you begin the experiment

Data collection and processing

Raw data obtained as a result of the experiment is exibited in Table 1 and that data is also presented in Graph 1.

Conclusion and evaluation

From the data obtained we can see that the highest emission of carbon – dioxyde was a result of glucose fermentation and therefore we can conclude that this sugar would be the optimal choice for maximizing energy efficiency of anaerobic respiration.

There are, however a couple of things that may make the final results of the experiment unvalid, and that is the inconsistency and subjectivity in the evaluation of the time interval between pushing the plunger inside and letting it com back, and the posiible leakages around the wooden corks, as well as their stability inside the test tubes.