BIOTECHNOLOGY Any technological process that uses living things to make or modify products or processes

BIOTECHNOLOGY PRODUCTS Biotechnology is about using living cells or enzymes. Biotechnologists use biological organisms or their enzymes to manufacture useful products or provide services for us e.g. Food production – beer, wine, yoghurt Production of chemicals – ethanol Waste treatment – sewage/hazardous substances/biodegradable products Energy source – fuels Agriculture – fertilizers Medicine – insulin, antibiotics

Growth of microbes Microbes are small organisms (living things) that can only be seen with a microscope They include bacteria, fungus and viruses Microbes require specific conditions in order to thrive, these include: Moisture Food Warm temperature (20 – 400C) Specific pH (not too acidic or basic) Most micro-organisms need oxygen (aerobic) a few can survive without (anaerobic)

FERMENTATION The process of using yeast to make beer and wine started before 6000BC Fermentation is another name for the production of energy from food without using oxygen. Glucose + yeast→ alcohol + carbon dioxide + energy

Respiration The term "respiration" describes any chemical process which releases energy from food. There are two types: aerobic respiration needs oxygen anaerobic respiration happens when no oxygen is available.

Energy Efficiency Aerobic respiration releases much more energy from a given amount of food. Anaerobic respiration, or fermentation, releases much less energy. Anaerobic respiration produces alcohol as a by-product when it happens in plants or fungi such as yeast. Fermentation in bacteria produces lactic acid as a by-product.

Best growing conditions Commercial brewers make sure that beer production is as efficient as possible by providing the best possible conditions for yeast to grow and ferment. This means that the temperature, oxygen supply and amount of glucose must be carefully controlled, and unwanted micro-organisms must be kept out.

Yeast as a microbe Yeast is a single celled, microscopic fungus which uses sugar as food. During bread making the baker is interested in the carbon dioxide the yeast produces. This gas makes the dough rise before baking. A brewer is interested in both the alcohol and the carbon dioxide made by the yeast. Beer is expected to be alcoholic and the carbon dioxide gives the characteristic fizz.

Food source? The brewing industry uses barley as the source of the food which the yeast ferments to make the alcohol in beer. However barley stores food in the form of starch - which is a type of food that yeast cannot use. In order to solve this, the brewer allows the barley grains (seeds) to germinate. Enzymes in the barley then convert the starch into maltose sugar, which the yeast can ferment. This process is called malting.

Yoghurt Making cheese and yoghurt are also processes which depend upon micro-organisms - in this case bacteria. The souring of milk is a fermentation process, as it takes place better when oxygen is absent. Fresh milk contains sugars and some bacteria. The bacteria feed on the sugars in the milk. The main sugar in milk is called lactose. Lactose is converted into lactic acid by bacterial fermentation, the increased acidity makes sours and thickens the milk.

Have a go! The following phrases refer to aerobic or anaerobic respiration. alcohol is made most energy release oxygen is needed lactic acid is made oxygen is not required Complete the table below by writing the phrases under the correct headings (aerobic/anaerobic respiration)