fermentation lab

AS and A Level Science

Fermentation Lab

PLANNING B

Materials:

6 Fermentation Tubes,

3 Thermometers

Equipment to recreate three different Environments (fridge, incubator, room with controlled temperature)

Enough Yeast to guarantee over 60mls for the six experiments

+ 30 ml of Sucrose

+ 30 ml of Starch

Ruler

Test Tubes

Measuring Cylinders, Graduated Cylinders

Indelible Pen

Stopwatch

Abundant supplies of Water for the CO2 measuring

These materials are needed only for my experiment, for the general class experiment use all these materials in greater quantities, therefore more than one stopwatch, and many more fermentation tubes etc., with also:

+ 200ml of Sucrose

+200ml of Starch

+ 200ml of Glucose

+ 600ml of Yeast

Method:

In this experiment we were supposed to note the different amount of CO2 by the different solutions at different temperatures. The polysaccharides have been chosen from a group of three: sucrose, starch or glucose. After this step we had to measure 10 ml of each in a measuring cylinder and then were dropped in 6 fermentation tubes. We then measured 10 ml of yeast; we repeated this step six times so that we had an equal number of fermentation tubes with the sugar. We then added the yeast to the fermentation tube. We shake the fermentation tube keeping our thumb on the opening. We recorded time from when there was no air in the fermentation tube. At the end of all this we will have three tubes with sucrose, and three with starch.

One test tube of sugar A and one test tube of sugar B were put in a fridge, were kept at room temperature or were put in an incubator. The fridge is at a temperature of 4 degrees Celsius, the room had a temperature of 20 degrees and the incubator had a temperature of 60 degrees Celsius.

We waited 45 minutes for the CO2 to ferment. We then noticed that an air bubble was formed and we put a mark with an indelible pen where the air finished and the liquid started. We then poured everything out and put an amount of water in the fermentation tube. The water was inserted according to the amount of CO2. We then convert the amount of water with the amount of CO2 ( 1ml of H20=1cm3)

DATA COLLECTION

Tables to show amount of Carbon Dioxide (in cm3) fermented in each different environment by the different groups using a fixed amount ...

This is a preview of the whole essay

DATA COLLECTION

Tables to show amount of Carbon Dioxide (in cm3) fermented in each different environment by the different groups using a fixed amount of Yeast and varying only the type of Sugar

Group I

Group II

Group III

Group IV

Group V

Group VI

Error is present in all the data that was recorded. Accuracy and efficiency were adopted yet some error is present in human and mechanical mistakes or inaccuracies, such can be quantified at the least as:

Time: +/-.5 seconds for each of the experiments

Initial measurement with the small measuring cylinders for the yeast and the sugars adds up to +/- 0.2 ml according to the equipment, yet the overall final measurement with the water created a much greater inaccuracy. Therefore the initial error could add up to the consecutive +/- 0.2 ml of water measurement.

* It should be recorded that great inaccuracies were made in the measuring with water for the very delicate and approximate nature of that calculation. If we add this error up with the initial error that could have been present we have great errors, and due to the very small nature of the results, often varying in few millimetres, then we see how error could play a huge part in this experiment.

DATA ANALYSIS

All data can be made more accurate using standard deviation.

Table to show Standard Deviation Values for the amounts of Carbon Dioxide fermented in cm3, for the various sugars with a fixed amount of yeast and in their different environments

*The temperature for the fridge, room and incubator as was earlier hinted is respectively 4, 20 and 60 degrees Celsius.

This data allows us to, using the previous table, analyse erroneous or at least inaccurate results.

Table to show results that apply to the Standard Deviations

Glucose used as Sugar

Starch used as Sugar

Sucrose used as Sugar

*in bold results that do not fit the First Standard Deviation. It is also evident that in the last row, the first number is the mean, followed by the range of the standard deviation around it.

We can therefore assume there to be general tendencies in the behaviour of the different sugars and the consequent amount of Carbon Dioxide fermented.

Table to show Average amount of Carbon Dioxide fermented by the different Sugars, in different environments with a fixed amount of Yeast

It appears that Sucrose is the sugar that when combined with Yeast, in a ratio of 10ml of Sucrose to 10ml of Yeast ferments most CO2 in all environments. Starch we can assume to be the least reactive, providing in all environments the least Carbon Dioxide out of its union with the living bacteria.

On a different note worth analysing is the anomaly in the behaviour of the yeast with all the three sugars. What we expected was to have a fermentation of Carbon Dioxide proportionate to the temperature increase, instead the results of all the three sugars and their various trials all prove this theory wrong. It appears that the bacteria in the Yeast works best at 60 C ̊than at 4C ̊and then at 20C ̊.

Table to show proportionate amount of CO2 fermented compared to 60C ̊seen as unit X in %

Therefore seeing the activity at 60 degrees as X it is clear how Yeast and the various sugars ferment much more, at times also double as much Carbon Dioxide at a cooler temperature than at the room temperature of 20 degrees.

EVALUATION:

This experiment therefore presents us with clear data regarding the fermentation of different sugars at different temperatures with a constant amount of Yeast. It does appear from all the results, despite some minor anomalies, that the Sucrose was the most fermenting sugar, followed by Glucose and lastly Starch. It also permeates how the Incubator environment allowed much more Carbon Dioxide to be fermented than the Fridge. The least Carbon Dioxide was fermented at room temperature. However we must understand that the very difficult nature of the final calculation of the air space, done by measuring with water the volume of gas, could once improved in accuracy upset all results.

Therefore the accuracy of this experiment, due also to the fact that very small units are the basis of the results implies that every error in the data collection has great relevance in the overall results and trends. Improving this field would greatly ameliorate the significance and accuracy of the results.

This experiment therefore could be improved with more accuracy in the final stages and maybe developing theories on why sucrose ferments more carbon dioxide than glucose or starch. Also the whole aspect of gasses escaping the fermentation tube was ignored, and in some cases the bubbles were recorded yet not analysed as linked to the Carbon Dioxide fermentation.