Micro-organisms understand the role of yeast in the production of beer describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions   understand the role of bacteria (Lactobacillus) in the production of yoghurt interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of microorganisms

Understand the role of yeast in the production of beer The best known fermentation reaction is the anaerobic respiration of glucose by yeast. This is also known as alcoholic fermentation. Glucose is the nutrient (also known as the substrate) that needs to be present in the culture medium for yeast to grow and reproduce. The word equation for alcoholic fermentation. Glucose  alcohol + carbon dioxide The waste products of the reaction are: Carbon dioxide Ethanol (alcohol). However if the alcohol concentration in the medium increased to over 9% the yeast would be killed because it would be too toxic.

Understand the role of bacteria (Lactobacillus) in the production of yoghurt Some of the characteristics of the Bacterial Kingdom no nucleus unicellular cell wall Circular DNA Lactobacillus uses Lactose (a sugar) to obtain energy. The word equation for this is: Lactose  lactic acid + energy Lactic acid gives yoghurt its sour taste. Pasteurising milk is the process where by the milk is heated before adding Lactobacillus. It is pasteurised in order to destroy any unwanted bacteria in the milk. If the pH of the enzyme is altered this could denature the enzyme which would mean it wouldn’t work as effectively.

An industrial fermenter

An industrial fermenter Air Supply Need oxygen for respiration Cooling Jacket Respiration creates heat The cold water helps to cool the fermenter Paddle Mix up the contents  ensure microorganims are in contact with food source and oxygen Air Out Waste gases need to be removed so that pressure does not build up Sterile Needs to be carefully cleaned to remove any unwanted micro-organisms