M. Brooke Hooper Microbiology Undergraduate student Microbiology Undergraduate student Biology department Biology department Tennessee Technological Univerisity Tennessee Technological Univerisity Cookeville, TN Cookeville, TN38505

Introduction I  Title: Affect of disaccharide concentration on the fermentation of saccharomyces cerevisiae  Objective: To relate affects of disaccharide concentration on the alcohol by volume percentage of wine from the fermentation of saccharomyces cerevisiae  Hypothesis: A stronger disaccharide concentration will yield a higher alcohol by volume percentage  Null hypothesis: a stronger disaccharide concentration will yield a lower alcohol by volume percentage

Introduction II  Saccaromyces cerevisiae is the yeast used in the fermentation of wine.  Bio-ethanol production from S. cerevisiae is presently the largest fermentation process in industrial ethanol production (Medina 2010).  During anaerobic growth of S. cerevisiae, sugar dissimilation occurs via alcoholic fermentation (Lin 2002).  Belonging to the kingdom Fungi,S. cerevisiae feed off of disaccharides for energy and fermentation as they acquire carbon from their immediate surroundings (Truckses 2004).

Introduction III  Yeast cells divide asymmetrically by budding (Kaeberlein 2008).  Ethanol fermentation from S. cerevisiae takes the following three steps (Devi 2000):  Development of a solution of soluble sugars  Fermentation of these sugars to alcohol  Purification of the ethanol

Materials & Methods   Six 0.35L bottles prepared with:   60ml Concentrated Grape Juice   Sugar solutions of 0g, 10g, 20g, 25g, 35g, or 45g.   Red Star Montrachet brand Saccharomyces cerevisiae  Each solution allowed to ferment in darkness for six weeks  Methods followed by:  

Materials & Methods ContainerDisaccharideJuiceWater A (control) none60ml240ml B10g60ml240ml C20g60ml240ml D25g60ml240ml E35g60ml240ml F45g60ml240ml

Home Wine Brewing

Materials & Methods  Data Collection: Specific gravities measured using a hydrometer before and after fermentation.  Equation: (specific gravity1- specific gravity2) x 125= ALCOHOL PERCENT BY VOLUME  Statistics: T-tests using Dr. Machida’s statistic tools Dr. Machida’s statistic toolsDr. Machida’s statistic tools

Saccharomyces cerevisiae Budding yeast cell Fermenting yeast cell

Results A positive correlation is noted between the increase in sugar and the increase of alcohol content.

Results   A negative correlation noted between increase of sugar concentration and the decrease of specific gravity.   A positive correlation noted between percent of alcohol and change in specific gravity   Specific gravities of each wine solution decreased with time   Ethanol Specific gravity=0.78 & Water Specific gravity=1.0   Null hypothesis rejected

Discussion  Benefits: amplification of understanding the ideal sugar amount required for optimal ethanol production.  Future Experiment 1: Study of other genus varieties.  Species S. diastaticus is distinguished from S. cerevisiae primarily by its ability to ferment starch (Innis 1985)  Future Experiment 2: Study of External factors  Glycerol protects the yeast cells in high osmolarity (Medina 2009).  Future Experiment 3: Study over max. lifespan/fermentation.  Cerevisiae become dormant after the ethanol % reaches a maximum or the yeast consume all of the sugar need for fermentation (Uptain 2002).  Future Experiment 4: Genetic study of genus  Gene redundancy: thought to be the consequence of whole-genome duplications in the species (Langki 2003).

Conclusions   A stronger disaccharide concentration will yield a higher alcohol by volume percentage.   A change in specific gravity connects with the percent alcohol by volume in a positive correlation.   A negative correlation is noted between increase of sugar concentration and the decrease of specific gravity as fermentation takes place.

Further Information    wine/ wine/ wine/  Works Cited Works Cited Works Cited

Citations  Devi, R. N., and S. Sumitra Bioconversion of cellulose into fermentable sugars by Saccharomyces cerevisiae cells for the production of ethanol using cellulolytic fungi isolated from soil. The Internet Journal of Microbiology 7: not applicable.  Home Brew Zone.“Using your hydrometer.” (March 17, 2010).  Innis, M.A., et al Expression, glycosylation, and secretion of an Aspergillus Glucoamylase by Saccharomyces cerevisiae. Science 228:  Instructables. “How to make wine.” (January 28, 2010).  Kaeberlein, M A molecular age barrier: a mother's instinct is to protect her children at any cost. In the budding yeast Saccharomyces cerevisiae this 'maternal instinct' comes at a high price--accelerated ageing and premature death. Nature 454:  Langkjaer, R. B., et al Yeast genome duplication was followed by asynchronous differentiation of duplicated genes. Nature 421:  Lin, S. J., et al Calorie restriction extends Saccharomyces cerevisiae lifespan by increasing respiration. Nature 418:  Medina, V. G., et al Elimination of glycerol production in Anaerobic cultures of a Saccaromyces cerevisiae strain engineered to use acetic acid as an electron acceptor. Applied and Environmental Microbiology 76:  Truckses, D. M., Lindsay S. G., and J. Thorner Jekyll and Hyde in the microbial world. Science 306:  Uptain, S. M., and S. Lindquist Prions as protein-based genetic elements. Annual Review of Microbiology 56: