Saccharomyces cerevisiae

HAWASSA UNIVERSITY
12/19/2018 2
MSc : clinical laboratory ( special truck diagnosis and
public health microbiology)
Course : microbial genetics
Lecturer : Moges Desta (PhD)
by : Abdikhaliq Hussein Ali

Learning Objectives
At the end of this module, participants will be able to:
Discuss the importance of the overview of Saccharomyces cerevisiae
Describe general features and genetic makeup of Saccharomyces
cerevisiae
Applications of Saccharomyces cerevisiae

Outline
 Introduction of Saccharomyces cerevisiae
 Genetic makeup of Saccharomyces cerevisiae
 Application of Saccharomyces cerevisiae
 Summery

Introduction to Saccharomyces cerevisiae
• Saccharomyces cerevisiae is (commonly known as baker’s
yeast) is a single-celled eukaryote. More specifically, it is a
globular-shaped, yellow-green yeast belonging to the Fungi
kingdom
• Other names of Saccharomyces cerevisiae :
• Brewer's yeast
• Ale yeast
• Top-fermenting yeast
• Baker's yeast
 First species domesticated by humans
 Called baker’s yeast (or brewer’s yeast)
 Ferments glucose to ethanol and carbon dioxide

Introduction
• S. cerevisiae has developed as a model organism for
studies of biochemistry, genetics, molecular and
cell biology because it scores favorably on a number
of these criteria:
rapid growth rate
easy to modify genetically
features typical of eukaryotes
relatively simple (unicellular)
relatively small genome

taxonomical Classification
• Domain: Eukarya
• Kingdom: Fungi
• Subkingdom: Dikarya
• Phylum: Ascomycota
• Subphylum: Saccharomycotina
• Class: Saccharomycetes
• Order: Saccharomycetales
• Family: Saccharomycetaceae
• Genus: Saccharomyces
• Species: Cerevisiae

General characteristics of Saccharomyces cerevisiae
• S. cerevisiae lives primarily on fruits, flowers and
other sugar containing substrates
• Free-living organism: yeast copes with a wide range of
environmental conditions:
 S. cerevisiae proliferate from 12°C to 40°C
Growth is possible from pH 2.8-8.0
Almost complete drying is tolerated (dry yeast)
 S. cerevisiae can still grow and ferment at sugar
concentrations of 3M (high osmotic pressure)
Yeast can tolerate up to 20% alcohol
S. cerevisiae have both a stable haploid and diploid state

Genetic makeup of S. cerevisiae

Genetic makeup of S. cerevisiae
 S. cerevisiae has two vegetative stages, haploids and diploids.
 This allows generating mutations/mutants in haploids and study the
consequences of such mutations directly.
 Furthermore, mutations can be allocated to genes by
complementation in diploids heterozygous for a mutation.
 Genetic relationship can be studied directly in the haploid progeny of
meiosis: gene mapping and functional relationship of different genes.
 Those were main features making yeast a model in the pre-genomic
era, i.e. can 1960-1990.

The lifecycle of S. cerevisiae

Diploid
Mitosis
Haploid
Mitosis
15

Pathogenicity
• Saccharoyces cerevisiae is not normally
considered to be a pathogen. In healthy people,
disease resulting from S. cerevisiae colonizing in a
particular area are very rare, but have been
reported.
• 1% of all vaginal yeast infections occur due to S.
cerevisiae in the vagina
• immunosuppressed individuals, followed by
those who have taken S. cerevisiae as an
probiotic for diarrhea

Traditional applications
• Brewing: Saccharomyces cerevisiae is used in
brewing beer, when it is sometimes called a
top-fermenting or top-cropping yeast.

applications
• Baking (Baker's yeast )
S. cerevisiae is used in baking; the carbon dioxide
generated by the fermentation is used as a leavening
agent in bread and other baked goods.

modern applications
• The yeast Saccharomyces cerevisiae is a key
cell factory already used for the production of
a wide range of industrial products.
Metabolic Engineering in Saccharomyces cerevisiae
Biopharmaceuticals
Agricultural and Biocontrol Applications
Environmental Applications
Biocatalysis and Fine Chemicals

Representative Commercial Recombinant Protein Pharmaceuticals and
Vaccines Produced in Yeasts (Johnson & Echavarri-Erasun, 2011)

summery
Saccharomyces cerevisiae is (commonly
known as baker’s yeast) is a single-celled
eukaryote. More specifically, it is a globular-
shaped, yellow-green yeast belonging to the
Fungi kingdom
First species domesticated by humans
Called baker’s yeast (or brewer’s yeast)
Ferments glucose to ethanol and carbon
dioxide

summery
• S. cerevisiae lives primarily on fruits, flowers
and other sugar containing substrates
The S. cerevisiae nuclear genome has 16
chromosomes.
In addition, there is a mitochondrial genome
and a plasmid, the 2μ circle.
The yeast chromosomes contain centromeres
and telomeres, which are simpler than those
of higher eukaryotes.

summery
Traditional applications
 Baking (Baker's yeast )
 Wine making
 Baking (Baker's yeast )
Modern applications
 Metabolic Engineering in
Saccharomyces cerevisiae
 Biopharmaceuticals
 Agricultural and Biocontrol
Applications
 Environmental Applications
 Biocatalysis and Fine
Chemicals
The yeast Saccharomyces cerevisiae is a key cell factory already
used for the production of a wide range of applications include:

References
• Ageitos, J.M., Vallejo, J.A., Veiga-Crespo, P., Villa, T.G., 2011. Oily yeasts as
oleaginous cell factories. Appl. Microbiol. Biotechnol., 90(4):1219-1227.
• Buijs, N.A., Siewers, N., Nielsen, J., 2013. Advanced biofuel production by the yeast
Saccharomyces cerevisiae, Current Opinion in Chemical Biology, 17: 480-488.
• Mustafa Türker, Pakmaya . April ,2014 Yeast Biotechnology: Diversity and
Applications publication at https://www.researchgate.net/publication/285598626
• Straathof, A.J.J., Panke, S. and Schmid, A.; The production of fine chemicals by
biotransformations, Current Opinion in Biotechnology 2002, 13:548–556.
• Wikipedia
https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae#In_commercial_applicati
ons

Saccharomyces cerevisiae

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