Yeast and Fermentation Biotechnology

Essential Questions: What are the key components in Yeast Growth Medium? How does yeast obtain energy through the processes of cellular respiration and fermentation?

Eukaryotic Cells Found in model organisms mice, rats, fruit flies, arabidopsis, and yeast What distinguishes a eukaryotic cell from a prokaryotic cell?

Example of Eukaryotic Cell Saccharomyces cerevisiae –yeast A fungus Found in sugar rich material (e.g. skins of fruits and berries and exudates from plants (such as plant saps or cacti).

Significance to Biotechnology Serves as eukaryotic model organism like E. coli for prokaryotes Important to Pharmaceutical Industry Ex. Important source of antibiotics and drugs to lower cholesterol Important to production of biofuels Genetic engineering Yeast to become more alcohol tolerant Ethanol used in biofuel production Important to the Food Industry Baking of bread Production of beer and wine

Culture Medium for Growing Yeast Like E. coli, can be grown in either a liquid (i.e. broth) or on a solid medium (i.e. agar) Typical broth used for yeast is YPD medium This broth contains Yeast extract (Y)-vitamins and trace elements Peptone (P) – amino acids Dextrose (glucose-D) - carbon source

Why does yeast need a carbon source? To make energy in the form of ATP needed for cell division and synthesis of key macromolecules-protein, carbohydrates, lipids, and DNA Yeast can make ATP in one of two ways Presence of oxygen by cellular respiration Absence of oxygen by fermentation

Cellular Respiration Process in which glucose is broken down to CO2 and water in the presence of O2 Most of the pathway occurs in the mitochondria Makes 34 ATP Property of CTE Joint Venture

Fermentation Process in which glucose is broken down to ethyl alcohol and CO2 in the absence of oxygen Occurs in the cytoplasm Makes less energy – only 2 ATP

PROPERTY OF PIMA COUNTY JTED, 2010 Think-Pair-Share Which pathway would humans use if they are O2 deprived? 3. Think-pair-share teacher presents a question teacher gives wait time for student to form answer teacher instructs students to share their answer with a partner teacher calls on non-volunteers to share with the class PROPERTY OF PIMA COUNTY JTED, 2010 Property of CTE Joint Venture

Example of How Yeast and Fermentation Is used in making root Beer Property of CTE Joint Venture

Ingredients of Root Beer Sugar Yeast Sassafras root Burdoch root Sarsaparilla root Spikenard root water

Sugar Sweetens the root beer Provides a carbon source for the yeast

Yeast Provide the biochemical process fermentation to generate CO2 for carbonation

Flavoring Comes from extracts of Sassafras root Burdock root Sarsaparilla root Spikenard root Instead of grinding up each root and extracting the flavor, we will use a root beer extract