Why are enzymes such as proteases and lipases used in some washing powders?

The role of enzymes such as proteases and lipases in the body is to break down proteins and fats respectively during digestion. Proteins are broken down into amino acids and fats are broken down into fatty acids and glycerol so these can be used elsewhere in the body. This occurs through what is known as a 'lock and key' hypothesis, where the enzyme can interact with these molecules, known as the substrates, due to them having a complimentary structure. The part of the enzyme that the substrate binds to is called the 'active site', which is specific for different enzymes- this is why only proteins are broken down by proteases and fats by lipases.The reason why these enzymes are added to what are known as 'biological' washing powders, is so they can help break down food-based stains on the clothes in the same manner as in the body, therefore making the washing powder more effective. It is because of this that enzymes are known as biological catalysts, therefore a high temperature is not needed with these washing powders, saving energy.