Sub-topic A Living factories Biotechnology Sub-topic A Living factories part 1

Biotechnology means using microbes to make useful products. Microbes include bacteria and yeast- a fungus. Useful products include bread, beer, wine, human antibiotics, insulin, biological detergents. Biotechnology is a major growth industry in Biology.

Yeast Yeast is a single-celled fungus. It uses sugar as a food supply nucleus cytoplasm cell wall Yeast reproduces new cells in a process called budding Word equation buds Sugar carbon dioxide + alcohol + energy

Anaerobic respiration (fermentation) Respiration in Yeast CREDIT Yeast respires glucose to obtain energy. If oxygen is present it will carry out aerobic respiration, which releases most of the energy from the glucose. Aerobic respiration glucose + oxygen lots of energy + carbon dioxide + water If oxygen is not available it will continue to respire anaerobically, but in doing so receives much less energy. Anaerobic respiration (fermentation) a little energy + carbon dioxide + Alcohol (ethanol) glucose

Fermentation Experiment CREDIT Control – the same as shown but use dead yeast thermometer Shows release of heat. bicarbonate indicator layer of oil Detects release of carbon dioxide. Oil keeps oxygen out of yeast and sugar mixture. Yeast in boiled and cooled glucose solution Boiling removes dissolved oxygen and kills all microbes. Cooling prevents yeast being killed when added. vacuum flask Prevents heat loss.

Bicarbonate indicator colour change Results CREDIT After 2 days; Experimental flask Control flask Thermometer reading Rises from 20oC to 23oC No change Bicarbonate indicator colour change Orange to yellow Distillation of liquid in flask at 80oC Ethanol collected No ethanol

Uses of Yeast Yeast is used in the baking and brewing industries. Respiration in yeast releases bubbles of carbon dioxide which spread through the dough, making it rise. Yeast Ferments the sugars in fruit and grains to produce alcohol.

Brewing Malting CREDIT Brewers Yeast releases energy from sugar in the absence of oxygen (anaerobically) to produce alcohol Alcoholic fermentation The sugars required are obtained from barley grains during a process called malting. Malting Barley grains are soaked in water for 2 days. The seeds germinate and the enzyme amylase changes starch into sugar. Endosperm (starch store)

Maltings Building CREDIT

Effect of germination on barley grains CREDIT dry barley grains contain starch but not simple sugar germinating seeds need; water oxygen warmth barley grains that have been allowed to germinate for a few days contain simple sugar but only a little starch Starch is broken down to simple sugar during germination Conclusion

this degradation process is brought about by an enzyme - amylase CREDIT amylase starch simple sugar normally in seed germination the sugar is used to provide food for the developing plant in brewing the sugar is used to provide food for yeast for fermentation

CREDIT After malting; The germinated barley grains are ground up with hot water to make a mash. This is sprayed with hot water to retrieve the sugars. The sugary liquid is boiled with hops in a wort kettle to give flavour and remove all unwanted microbes. The resulting mixture (called wort) is cooled, yeast are then added and grown under ideal conditions in a fermenter. The resulting beer is allowed to mature in casks.

growing condition required by yeast CREDIT growing condition required by yeast way in which growing condition is provided starch converted to sugar for yeast by germinating barley grains on floor of malting house food supply suitable temperature temperature of fermenter vessel controlled by thermostat all other micro-organisms killed by boiling in wort kettle before yeast is added lack of competition

Fermenters CREDIT A fermenter is a vessel which can be used to manufacture a range of products in the presence or absence of oxygen. They can be small and simple …. … or large and complex – needing to be monitored by computer.

Brewing -- Commercial Batch Processing CREDIT

Batch Processing CREDIT This is the technique used by commercial brewers to provide the best conditions for fermentation. The common feature of all batch processes is that they involve closed systems. After the addition of the raw materials, nutrients and yeast culture, the system is left untouched, although controlled, until fermentation ends. Fermentation ends because nutrients run out or waste materials build up. The beer then has to be drawn off and separated from the yeast, and the fermenter system needs to be cleaned and sterilised before being re-used. This wastes time and money.

In brewing, the fermenter is a large copper tank into which are placed the nutrients and yeast CREDIT Sensors monitor the pH, temperature and oxygen concentration to provide ideal growing conditions for the yeast. ( about 10oC – 18oC and a pH of about 7) (Respiration produces heat)

Immobilisation CREDIT Immobilisation involves attaching a cell or enzyme to another substance so that it can’t move freely. Whole cells such as yeast can be trapped inside gel beads. Enzymes can be attached to glass beads. enzymes enzymes attached to glass bead

Free Yeast Immobilised Yeast

CREDIT Many industries use immobilised cells or enzymes because; Products are separated easily and cheaply from cells or enzymes Products are easily purified. Less waste as cells / enzymes can be re-used Can be used in continuous flow processing

Commercial Continuous Flow Process CREDIT Commercial Continuous Flow Process

Continuous flow processing CREDIT Continuous flow processing Raw materials continuously fed in Fermenter vessel Glass / gel bead Product continuously removed Enzyme (or cell) immobilised to glass / gel bead

Continuous Flow Process; CREDIT Can be expensive to develop and set up, but; Raw materials are continuously added to the fermenter, so the cells / enzymes receives a steady stream of raw materials. Product does not have to be separated from cells / enzymes, so money saved. Cells / enzymes can be used again, so money saved. Valuable time not lost in cleaning out and re-setting fermenter as in batch processing. Less waste and pollution as cells / enzymes not discarded.

Milk Fermentation by Bacteria Fresh milk from a cow contains many bacteria The bacteria multiply and make the milk go sour. Lactose sugar in milk is broken down by bacteria to lactic acid Milk is pasteurised before we can drink it to remove harmful bacteria. Putting the milk in the fridge slows down the growth of any remaining bacteria. The souring of milk by producing lactic acid is a “Fermentation process” Bacteria Lactose sugar Lactic Acid CREDIT

Making yogurt Yogurt relies on the souring of milk by bacteria. The milk is sterilised by heating Bacteria are added The bacteria feed on the milk sugar (lactose) and convert it to lactic acid , this makes the milk curdle and go lumpy and gives yoghurt its sour taste Flavourings and colourings are added to give the final product.

How Cheese is Made Bacteria are added to the milk to make it go sour. Next an enzyme called rennin is added. This breaks down the proteins in milk and causes the milk to separate into solids (curds) and a liquid (whey).

The liquid whey is then drained off. The curd is finally allowed to ripen and mature to form cheese. Some cheeses are then flavoured by adding different microbes. Blue stilton