Can yeast ferment polysaccharides as efficiently as disaccharides?
By Nashai Pillay
Table of Contents Page
Review of Literature4
Processing of Findings8
Can yeast ferment polysaccharides as efficiently as disaccharides?
The yeast will ferment polysaccharides more efficiently than disaccharides.
The aim of my project is to see how efficiently yeast ferments polysaccharides compared to how yeast ferments disaccharides.
Why I Chose It
I chose this topic because, I was very interested to observe the breaking down of different sugar molecules through the process of fermentation, and how different sugars react differently in certain circumstances.
Review of Literature
Yeast is a microorganism part of the fungus kingdom, and they are mostly found in soils and on the surfaces of plants (Encyclopedia Britannica). Yeast has over 500 types of species.
The DNA of yeast is in the nucleus and yeast also has mitochondria. Yeast converts sugar from liquid to alcohol, therefore due to this fact, it was discovered that yeast had many other purposes than just being a chemical catalyst as believed back then.
Polysaccharides are carbohydrates that have molecules which consist of a number of sugars bonded together. They are large molecules made of many monosaccharides, (monosaccharides being the different types of sugars). The three main types of polysaccharides are starch, cellulose and glycogen. There are two types of polysaccharides: homopolysacharides (the monosaccharides are the same), and heteropolysaccharides (the monosaccharides are different).
Polysaccharides have many different functions such as: storing energy, providing support to cells and tissues and sending cellular messages. (Biology Dictionary). Polysaccharides represent a major part of a yeast cell wall and they build the skeletal carcass defining cell wall stability. (US National Library of Medicine).
Disaccharides are sugars that are formed with two monosaccharides. The three most common disaccharides are sucrose, lactose and maltose. For disaccharides to be absorbed, they need to be digested first. (Nutrients Review). One function of a disaccharide Is a good energy source. According to Tessa M. yeast uses sugar to convert monosaccharides into carbon dioxide and ethanol.
Yeast fermented sucrose more efficiently (Science and Plants for Schools), therefore coming to the conclusion that yeast ferments disaccharides more efficiently than polysaccharides. Although we cannot take that as the most correct conclusion, as other sources have stated that polysaccharides are fermented more efficiently, or that both polysaccharides and disaccharides ferment at the same rate.
Due to this result unbalance, I am testing to see whether one ferments faster than the other or if they both ferment at the same rate. Hence my research question: Can yeast ferment polysaccharides as efficiently as disaccharides?
Prepare a 1 molar solution of sucrose, maltose, and cellulose. To prepare 1 molar solutions measure the molecular mass of each substance using a triple beam balance.
Label three flasks with molar concentration and solution name.
Transfer the weighed substances to a 1 Liter flask and dissolve in 800 milliliters of water. Once the substance is fully dissolved, add an additional 200 milliliters of water.
Measure 5 grams of yeast onto a tray.
Transfer the yeast to fit inside the rubber end of the dropper.
Reattach the rubber end of the dropper to the glass tube it came from keeping the dropper inverted.
With the inverted dropper place inside a test tube. The rubber end of the dropper with the yeast inside should rest at the bottom of the test tube.
Add 4 milliliters of the 1 molar sucrose solution inside the dropper and fill the test tube with tepid water.
Record the number of carbon dioxide bubbles that evolve from the rubber end of the dropper.
Repeat steps 4-9 for the maltose and cellulose solution.
Processing of Findings
A table showing the comparison of the mass of carbon dioxide vs. the time for the fermentation of sucrose (disaccharide)
Time (minutes) Mass of Carbon Dioxide released (g)
A line graph showing the comparison of the mass of carbon dioxide vs. the time for the fermentation of sucrose (disaccharide)
A table showing the comparison of the mass of carbon dioxide vs. the time for fermentation of sucrose and glucose (polysaccharide and disaccharide).
Time (minutes) Sucrose Glucose
30 0,8 0,6
60 1,8 1,7
90 3,5 2,2
120 5,1 2,8
160 6,7 3,4
190 6,8 4,2
220 8,1 4,8
260 8,8 5,3
290 8,8 6,2
320 9,2 6,3
A line graph showing the comparison of the mass of carbon dioxide vs. the time for fermentation of sucrose and glucose (polysaccharide and disaccharide).
A table showing the comparison of the mass of carbon dioxide released vs. the time for the fermentation of the glucose (polysaccharide).
Time (minutes) Mass of carbon dioxide released (g)
A line graph showing the comparison of the mass of carbon dioxide released vs. the time for the fermentation of the glucose (polysaccharide).
Due to the information supplied above, my results reflect what my literature review states, which is that sucrose(disaccharide) was fermented more efficiently than the polysaccharide. Therefore, proving my hypothesis incorrect, and proving that my literature review is correct.
Therefore, due to the above given information, my hypothesis being that yeast would ferment polysaccharides more efficiently than disaccharides is proved to be incorrect, therefore the conclusion being that disaccharides are fermented more efficiently than polysaccharides.
John Hewitson and Charles Hill. How Does Sugar Affect Yeast and Growth? Science and Plants for Schools. Available: http://www.saps.org.uk/saps-associates/browse-q-and-a/169-q-a-a-how-does-sugar-affect-yeast-growth .5 March 2018.
Tessa M. Polakowski. March 2008. The Effect of Different Sugars on the Rate of Fermentation in Yeast. EBSCO Information Services. Available: http://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=00300950&AN=31746029&h=DCf3ri%2bY9tu0yrAnZVmrg0SavbvulFgcC6uA67o5k%2bYKN5RINkyPR7AOy499ei0AypKwbcDH51%2bzRsHNeabAtw%3d%3d&crl=c&resultNs=AdminWebAuth&resultLocal=ErrCrlNotAuth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d00300950%26AN%3d31746029 . 3 March 2018 .
Disaccharides. Nutrients Review.com. Available: http://www.nutrientsreview.com/carbs/disaccharides.html . 29 February 2018.
Polysaccharide. Biology Dictionary. Available: https://biologydictionary.net/polysaccharide/ . 4 March 2018.
Yeast Facts. SoftSchools.com. Available: http://www.softschools.com/facts/organisms/yeast_facts/2897/ . 1 March 2018.
Can Yeast Ferment Polysaccharides as Efficiently as Disaccharides? education.com. Available: http://www.softschools.com/facts/organisms/yeast_facts/2897/ . 7 February 2018.