1. Detergent Industries Chapter 7

2. Enzymes Made by all living cells Speed up chemical reactions Work best at warm temperatures (e.g 40oC) Above 60oC, they are destroyed In the body, they help with digestion - break large molecules into smaller particles

3. ‘Biological’ detergents A detergent containing enzymes Enzymes digest stains - break large particles (e.g. protein) down into small particles Non-bio detergents have no enzymes Enzymes used are produced by bacteria Bacteria grown in an industrial fermenter Whilst growing, they release enzymes Some people suffer from allergies to ‘bio’ detergents - enzymes can be coated

4. Advantage of using biological washing powder Reduce fuel costs – work at lower temperatures Less damage to fabrics – less ‘shrinking at low temperatures Can remove ‘difficult’ stains, that non-bios can’t - e.g. grass, blood Bio detergents often contain several types of enzyme - e.g. protein-digesting, starch-digesting, fat- digesting

5. Environmental impact To supply electricity, power stations burn fossil fuels Release CO 2, sulphur dioxide (SO 2 ) - CO 2 helps global warming - SO 2 can lead to acid rain Bio-detergents can reduce the need for electricity

6. Detergents on wildlife Detergents are rich in phosphates Sewage works break down waste water and detergents into harmless wastes - bacteria are used to digest the waste Some detergents can kill sewage bacteria Waste water can pass through sewage works untreated Untreated waste appears as clouds of foam Phosphates can act as fertilisers - can help green algae grow in rivers/streams - too many algae use up all the oxygen To reduce the damage caused by phosphates….