Biotechnology

Microorganisms used in food production

Yeast (fungus)

• Used to make bread, beer and wine in the process of fermentation.

• Learning Intentions– Understand biotechnology’s use of bacteria

• Success Criteria

• All can– I can state 3 uses of yeast and describe yeast– I can state the word equation for glucose fermentation

• Most Can– I can describe and compare aerobic and anaerobic

respiration– I can describe the manufacture of beer– I can explain batch processing– While discussing the need to malt barley I can give

ideal growing conditions for yeast.

Biotechnological Process

• This is a process in which living cells are used to convert a raw

material into a useful substance.

Biotechnological Processes

Raw materials

Services

Sewage treatment, water purification

Suitable micro-organisms

Products

Food, enzymes, fuel, antibiotics, hormones

Yeast at Work• Yeast is a tiny living thing, called a microbe.• As you can see it is made of single cells.• It is a type of plant called a fungus, (no

chlorophyll).• It is used in baking and brewing. Budding.

Yeast

Yeast is seen as a grey dust (bloom) on fruits.

A long time ago people crushed fruit and due to the yeast on the surface of this fruit it fermented making alcohol.

Yeast at Work• Remember the equation for aerobic respiration?• Glucose + Oxygen water + carbon dioxide

+ energy

• All cells carry out this process, including yeast.• However, biotechnology is about creating useful products and

carbon dioxide and water are not very profitable.

• If you take away oxygen though (anaerobic respiration)– Glucose (sugar) alcohol + carbon dioxide

+ energy• So this is how alcohol is produced.• This is called Fermentation

• When making alcohol the process is called alcoholic fermentation.

• Yeast obtains energy by doing this.

Barley Grains• The energy seeds need to grow is stored

inside them as starch.• When they start to grow they convert this

starch to simple sugars using what enzyme?– Amylase

• Beer making uses Barley for energy for the yeast.

• However starch is too large for yeast to digest so the grains have to be first left to germinate to make sugar.

• This is called malting.

Grains allowed to germinate to make sugar (seeds stopped for using sugar themselves)

Dead sprouted grains (malt) mashed and dissolved into water = wort

Hops added for flavour and wort boiled to kill bacteria and wild yeast

Cooled and yeast added. Fermentation stops when alcohol kills yeast

Beer stored to allow it to mature and filtered to remove sediment.

Spend grains = cattle food

Spent hops = fertiliser

• Learning Intentions– Understand biotechnology’s use of bacteria

• Success Criteria

• All can– I can state 3 uses of yeast and describe yeast– I can state the word equation for glucose fermentation

• Some Can– I can describe and compare aerobic and anaerobic

respiration– I can describe the manufacture of beer– I can explain batch processing– While discussing the need to malt barley I can give

ideal growing conditions for yeast.

Bacteria in food production

Converting Milk to Yogurt or Cheese uses lactobacillus

• Learning Intentions• Describe the uses of bacteria in biotechnology

• Success Criteria

• All can– I can describe the process of cheese making– I can describe the process of yoghurt making– I can state that the souring of milk is a fermentation

process– I can explain the souring of milk in terms of

fermentation of lactose

Milk

• Fresh milk straight from the cow usually has a lot of bacteria.

• These bacteria feed on the milk (source of food) and grow and multiply.

• It is for this reason milk is treated.

• The bacteria respire anaerobically (with out oxygen) and feed on the sugar in milk (lactose) turning it to lactic acid.

• This makes milk sour.• The souring of the milk is a further example of

fermentation.

• Lactose Lactic acid

• This is called Lactic acid fermentation

Cheese and Yoghurt

• To make cheese and yoghurt milk has to curdle and lactic acid makes this happen.

• To make Yoghurt

1. Pasteurise milk (heated 73oC for 15s)

2. Let cool to 40 degrees celcius

3. Add yoghurt making bacteria (converts sugar to lactic acid = curdling)

4. Notice the lowering pH as bacteria convert lactose to lactic acid

5. Yoghurt is formed as lower pH denatures proteins in milk (curdling) over several hours.

6. Stored in fridge to slow down bacteria growth

• Learning Intentions• Describe the uses of bacteria in biotechnology

• Success Criteria

• All can– I can describe the process of yoghurt and cheese

making– I can state that the souring of milk is a fermentation

process– I can explain the souring of milk in terms of

fermentation of lactose

Large Scale Microbe Production

Learning Objectives

1. To understand how microbes are cultured on a large scale.

2. To know how fungi can be used as a meat substitute.

On a small scale• You can grow

microbes on a small scale in a petri dish.

• They can get plenty of food, oxygen and warmth to grow.

On a small scale

• Waste that bacteria produce is not a problem on a small scale.

Simple Fermentation in the School LaboratorySimple Fermentation in the School LaboratoryIn the school laboratory you may have used apparatus similar to that shown below to investigate the effect of temperature or glucose concentration on the rate of respiration in yeast.

The yeast culture is growing in conditions where the temperature is controlled and glucose is provided - this is a basic fermenter.

On a large scale

• On an industrial scale, waste can become a problem.

Uses of Microbes

- Antibiotics - Food

How do we go from

this…………….….to………….…..this…..?

A graph to show what is happening in the fermenter

Problems with fermenters

- As numbers of microorganisms increase;

1. The food is used up.2. The temperature increases as they respire.3. Oxygen levels decrease as they respire.4. As the carbon dioxide levels increase, the pH

changes.5. As waste increases the microorganisms begin to

die.

Industrial Fermenters - FeaturesIndustrial Fermenters - Features

So what do we have to do to overcome these problems?

- Oxygen is supplied for respiration.- There is a stirrer to keep the microorganisms

spread out (not settling to the bottom) and the temperature the same.

- There is a water cooled jacket around the outside, to try and maintain the temperature, as the microbes release heat.

- There are sensors to monitor the pH and temperature.

Mycoprotein Production

• A new substance was discovered not long ago, a food based on fungi, and it is called mycoprotein.

• It is produced using the fungus Fusarium, which grows and reproduces very rapidly based on a cheap energy supply (an inexpensive sugar syrup made from waste carbohydrates) in a large fermenter.

Mycoprotein Production

• It does require areobic conditions to grow. Its mass doubles every 5 hours or so, and this biomass is harvested, purified and dried to leave mycoprotein.

Mycoprotein Production

• On its own, it is pale yellow in colour and tastes faintly of mushrooms.

• But a range of colours and flavours can be added to it to enhance it.

Mycoprotein Production

• Mycoprotein serves as a high-protein, low-fat meat substitute. This means it is good for dieters and vegetarians.