1.3: Biotechnology in Food Production Flashcards
What are examples of industrial microbial products?
- health and food products (lysine, vit B12)
- pharmaceuticals (oestrogen, cortisone, penicillin)
- food (mycoprotein or Quorn)
- beer/wine
What are the three stages of setting up an industrial process?
- laboratory scale
- pilot plant scale
- industrial plant scale
What does the laboratory scale consist of?
- Grow microorganism which has been found to make a useful product in small flask (200cm3)
- Check that product can be produced
- Purity of product is checked
- Optimum conditions for growth determined
What does the pilot plant scale consist of?
- A small fermenter (200-500dm3) is used to culture the microorganism
- Check that reaction works when scaled up
- Check that any gases produced can be ventilated
- Optimum operating conditions are confir
What does the industrial plant scale consist of?
- Microorganism is grown in a large industrial fermenter (bioreactor)
- This is thousands of dm3 in volume
What are the problems encountered with scaling up?
- Small scale fermenters are stirred by a small electric mixer, using a small quantity of electricity
- If it were scaled up directly in proportion to the vessel the mixer would be too large, need too much electricity and generate too much heat. Therefore alternative methods of mixing may be needed
- Large volumes of liquid are slow to heat and cool
- Maintenance of sterile conditions
Difficulties in maintaining constant flavour/quality - Errors can lead to loss of several days production
Label the fermenter/bioreactor
what are the functions of a stirrer?
stirs the contents of the fermenter so that cells are constantly brought into contact with fresh medium
What is the function of the water jacket?
contains cold water which circulates constantly to keep the contents of the fermenter from over heating
What is the function of the acid/alkali inlet?
maintains a constant pH for optimum growth conditions
What is the function of the sterile air inlet?
allows sterile O2 in if organisms are aerobic or adds CO2 if organisms are anaerobic
What is the function of the air inlet?
allows venting of waste gases
What is the typical growth curve for bacteria?
What is the difference in fermenter between batch and continuous culture?
- batch - Carried out in a closed fermenter
- continuous: in a closed fermenter
What is the difference in addition of microorganisms and nutrient medium between batch and continuous culture?
- Batch: Microorganism and nutrient medium are added at the start and product is extracted at the end
- Continuous: Nutrients added and products removed continuously
What is the difference in growth curves between batch and continuous culture?
- Batch: Short phase of exponential growth
- Continuous: Phase of exponential growth of microorganism maintained
How hard is it to monitor and maintain environment in batch and continuous culture?
- Batch: Easy to set up and control the conditions
- continuous: Can be difficult to monitor environmental conditions
What happens if contamination occurs in batch and continuous culture?
Batch: Only 1 batch lost if contamination occurs
Continuous: if contamination occurs, there is a considerable waste. costly
What can happen in continuous batches?
Foaming, clumping and blockages may occur
What is the growth curves of a microorganism grown in a continuous fermenter?
What is beer made from?
Malted Barley
What is the first step of the beer making process?
- Grains are soaked for 2-3 days
- Incubated at 13 – 17 ° C for 10 days
- Grain germinates and produces amylase enzymes which convert starch to maltose
What is the second step of the beer making process?
- The temperature is raised to 40 – 70 °C
- This denatures enzymes and stops germination
- This is often carried out by specialist maltsters and the malt is sent to the brewery
What is the third step of the beer making process?
- The roasted grains are cracked open by passing between rollers
- The crushed malt is called grist
- This is mixed with hot water in a large container called a mash tun
How long does the mash stand for?
2 hours so that the sugars dissolve, then passes into another vessel where the sugar liquid is drained off
What happens to the grain when the wort is drained off?
- The grain is sprayed with hot water to wash out the sugars
- The spent grain is sold for cattle feed
Why is the hop added to the grain?
To add flavour