Micro organisms Flashcards
Bacteria ferment milk to produce……
Yoghurt
What is fermentation?
When microorganisms break sugars down to release energy, usually by anaerobic respiration.
Why is lactobacillus bacteria added when making yoghurt?
Lactobacillus bacteria ferments the lactose sugar in the milk to form lactic acid. Lactic acid causes the milk to clot and solidify into yoghurt.
Why can microorganisms, like bacteria be useful?
They can be used to make penicillin or insulin
In industry, microorganisms are grown in large containers called………
Fermenters
What is the name of the liquid in the fermenter in which microorganisms can grow and reproduce?
Culture medium
Why are the conditions in the fermentation vessels kept at the optimum levels?
For the best levels for growth, which means yield of products from the micro organisms to be as big as possible
When the oxygen runs out the yeast switches to anaerobic respiration, this is also known as…….
Fermentation
Why is the pH monitored and kept an optimum level in fermenter?
For the micro organisms’ enzymes to work efficiently which keeps the rate of reaction and product yield as high as possible.
What is used around a fermenter to keep the temperature at an optimum level?
A water-cooled jacket to make sure it doesn’t get so hot that the enzymes denature
What is the purpose of the paddles that circulate / agitate the medium around the vessel?
To ensure the microorganisms are kept in contact with fresh medium which increases the yield because they always have access to nutrients that they need for growth
Why is sterile air pumped into the fermenter?
To provide oxygen so the micro organisms can respire to provide energy for growth, to increase yield
Why are vessels sterilised between uses with superheated steam?
To kill unwanted microbes as having aseptic conditions increases the yield because the microorganisms are not competing with other organisms. It also means the product does not get contaminated.
Why is yeast a useful microorganism?
When it respires aerobically it breaks down sugar into CO2 and water. In baking the bubbles of CO2 make the dough rise.
