Microbiology and Yeast Cell Fermentation

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Microbiology and Yeast Cell Fermentation
Photo from Flickr.com
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What are Microbes?

• Microbes Living things that must be greatly
  magnified to be seen. They include bacteria,
  fungi and viruses.

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What is Microbiology?

• Microbiology is the study (logy) of very small
  (micro) living (bio) things. One of the most
  famous microbiologist is Louis Pasteur. Pasteur
  performed experiments that proved that microbes
  cause fermentation.

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What is fermentation?

• Fermentation A process of growing
  microorganisms (microbes) to produce various
  chemicals or pharmaceutical compounds.

Fermentation of microbes is how most
Biotechnology companies products such as enzymes
and medicines.
Definition from Mapping your Future Exploring
Careers in Biomanufacturing
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What is yeast?

• Yeast A general term for single-celled fungi
  that reproduce by budding.

Some yeast can ferment carbohydrates (starches
and sugars) and thus are important in brewing and
baking.
Yeast cells under the microscope.
Yeast cells budding.
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What do yeast cells need to grow and survive?

• Carbon (sugar source)
• Nitrogen (protein source)
• Vitamins

Yeast feeds on sugar from a variety of sources,
including fruit, grain, nectar and molasses.
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How DID Biotech first use microbes?

• Around 4000 BC, Egyptians used the living
  organism yeast to make bread. Airborne wild yeast
  accidentally got their bread dough, causing it to
  rise.

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How does yeast affect the bread making process?

• Bread Dough is made with flour which contains
  nutrients and sugar that the yeast cells digest.
• When the yeast eats the sugar, it gives
  off 2 waste (by) products The chemical
  reaction is written as follows
• YEAST SUGAR
• CARBON DIOXIDE ALCOHOL

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How do the by-products of yeast fermentation
influence the bread making process?

• The carbon dioxide is what makes the dough rise
  and give it a light, airy texture.
• The alcohol evaporates during baking and gives
  off that wonderful aroma of baking bread.
• The baking destroys the yeast.