bacteria, yeasts (single celled fungi) and moulds are all examples of micro-organisms. scientists cultivate (grow) micro-organisms in a liquid that contains nutrients and a source of energy. This liquid is called the culture medium.
As they grow, micro-organisms use up the nutrients in the culture medium, and produce waste products and other substances. This process is called fermentation.
Making wine or beer :
Yeast is given sugar ---> uses the sugar as a nutrient + a source of energy -->
sugar is broken down to leave two waste products: carbon dioxide and alcohol (ethanol).
the nutrients and energy source that are added depend on the type of microorganism used. some micro-organisms use different sugars, such as sucrose or glucose. other…