17 December 2012

#24 Use of enzyme in biological washing powders

Biological washing powders contain protease and lipase to remove protein stains and fat/grease from clothes. The enzymes break down proteins or fats on the fabric, forming water-soluble substances that can be washed away.

Example: Blood contain the red protein Haemoglobin (Hb). The Proteases in biological washing powder break Hb molecules into smaller molecules, which are not coloured and which dissolve in water and can be washed away.  

This makes the washing powder more effective than detergent alone, especially at lower temperatures. This save energy (no need to boil water), but if the temperature is too high, the enzyme will be denatured.

Do it your self

Boil two standard eggs together, and push two teaspoons into the yolks so that there is some yolk left on the spoons.

Dissolve equal amounts of ordinary and 'biological' detergents in two separate glasses of water, and leave a yolk-stained spoon in each glass. After some time you will see that the spoon in the ordinary detergent still has yolk on, but the yolk on the other spoon has been digested by the 'biological' detergent. This will happen if the 'biological' detergent really contains 
enzymes that break down the proteins in egg yolk.

Try this

Figure above shows a box of biological washing powder.

a) Explain why:
   i) The presence of protease and lipase would make the washing powder more effective than ordinary detergent                              [3 marks]

   ii) The powder should not be used in boiling water           [2 marks]

b) Silk is a material made from protein. Explain why the biological washing powder should not be used to wash silk clothes                  [2 marks]


a)   i) Protease and lipase are enzyme
       They break down stains better than ordinary detergent
       Protease breaks down protein; lipase breaks down fat
    ii) Enzymes are denatured at high temperature
b)  There is protease in the biological washing powder
   This would digest the protein in the silk so the clothes would get spoiled.

Benefit from using enzymes in cleaning products, toothpaste and other products in our home. 

      Additional sources:

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