Basic Knowledge Questions
1. What is yeast?
Fungi,
Eukaryotic, single-celled micro-organism
Leavening agent
2. What is the scientific name of yeast?
Saccharomyces cerevisiae
3. What is the process of fermentation?
Primary, secondary, condition,
Metabolic process
Anaerobic respiration
Extraction of energy from carbohydrates in the absence of oxygen to produce carbon dioxide
4. What types of molecules does yeast need to conduct fermentation?
Basic sugar substrate, oxygen for growth, carbon dioxide
5. What carbohydrate source or mixture of sources affect fermentation the most?
Glucose (the greatest rate), carbon dioxide product is the greatest
6. What types of substrates and enzymes can yeast be used in the process of fermentation?
Maltase and invertase enzymes,
Glucose substrate
7. How do these enzymes function?
Yeast produces these enzymes to make simple sugars for cell growth and fermentation
8. How does ethanol concentration affect the yeast?
High ethanol increases cell death chances, decrease cell volume and specific growth rate inhibits
cell division
, Literature Review Questions
1. Fermentation using yeast article:
Yeast ferments carbon sources to produce ethanol and carbon dioxide. The yeast cell cycle haplo-
and diplophases.
horizontal gene transfer, changes in the gene copies number, chromosomal rearrangements,
hybrid genome breakdown, intraspecific hybridization.
Davydenko, S., Meledina, T., Mittenberg, A., Shabelnikov, S., Vonsky, M., & Morozov, A.
(2020). Proteomics Answers Which Yeast Genes Are Specific for Baking, Brewing, and Ethanol
Production. Bioengineering (Basel), 7(4), 1–15.
https://doi-org.lscsproxy.lonestar.edu/10.3390/bioengineering7040147
What impacts yeast fermentation article:
Temperature, pH value that is lower than pK, acetic acid (4.75 at 25 degrees Celsius)
Cellulose and hemicellulose chemicals, can increase acetic acid
Iron ions can catalyze the reaction and formation- oxidative damage
High ethanol concentration which can cause the cell to mutate
Environmental stress levels that the yeast endures needs to be adaptable or perfect conditions for
the conduction of the experiment
Vamvakas, S.-S., & Kapolos, J. (2020). Factors affecting yeast ethanol tolerance and
fermentation efficiency. World Journal of Microbiology & Biotechnology, 36(8), N.PAG.
https://doi-org.lscsproxy.lonestar.edu/10.1007/s11274-020-02881-8
2. Different types of yeast used for baking and brewing article:
Saccharomyces cerevisiae (top) - wine brewing yeast, improves ethanol tolerance
Vamvakas, S.-S., & Kapolos, J. (2020). Factors affecting yeast ethanol tolerance and
fermentation efficiency. World Journal of Microbiology & Biotechnology, 36(8), N.PAG.
https://doi-org.lscsproxy.lonestar.edu/10.1007/s11274-020-02881-8
Top-fermenting Saccharomyces cerevisiae and bottom-fermenting Saccharomyces pastorianus
including their strains and hybrids. Differences are growth and fermentation temperature,
forming of fermentation by-products or cell complexes.
Brewing yeasts are usually the bottom-fermenting Saccharomyces used for ‘wheat beers’