6.2.1 Cloning And Biotechnology Flashcards
What is biotechnology
Industrial use of living organisms to produce food, drugs or other products
Or to carry out useful services - sewage treatment, composting and bioremediation
Mostly use microorganisms or parts of living organisms to make products
Why are microorganisms used
Reproduce rapidly
Have simple growth requirements
Occupy very little space
Can be genetically engineered
Grow at relatively low temps
Can be grown anywhere in the world
Produce pure products
Can be grown on an industrial scale to perform duties useful to large numbers of population
Types of enzymes used
Intercellular enzymes - Enzymes used in industry which are contained within the cells of an organism
Isolated enzymes - enzymes use that are not contained within cells
Some are secreted naturally- extracellular enzymes
Common processes that use biotechnology
Brewing and baking
Baking bread
Cheese making
Yoghurt making
Penicillin production
Insulin production
Mycoprotein production
Bioremediation
Possibility of:
Production of biofuels - replace fossil fuels
Production of vaccines + antibodies
Brewing and distillation
Uses yeast species to respire sugars from barley malt an produce ethanol and CO2
Anaerobic process - fermentation
To increase alcohol content - ferment first then distill further
Baking bread
Whetstone or rye flour mixed with yeast and other ingredients to make dough
Commercial bakers carefully control the species of yeast usedb
Yeast enzymes begin by hydrolysing the starch in flour to maltose
Maltose is thenhydrilywes to produce monosaccharides which can be used for aerobic respiration
When O2 runs out, yeast respires anaerobically
Produce CO2 bubbles which cause the dough to rise
Baking kills the yeast + causes gas pockets in the dough to expand
Yoghurt making
Started culture of Lactobacillus bulgaricus and Streptococcus thermophilus bacteria are introduced to pasteurised milk
Bacteria use sugars in the milk to respite and produce lactic acid as a waste product
Lactic acid denatures the proteins in the milk, causing them to conjugate
This produces the thick texture and sour taste
Cheese making
Pasteurised milk used as a raw material
Add rennet to the milk
Enzyme chymosin clots the milk
Lactic acid bacteria are added which converts lactose in the milk into lactic acid
Makes it turn sour and solidify
The liquid portion (whey) is removed from the curd
The curd is then pressed into moulds and the different treatments while making the curd determine the characteristic flavour and texture of the cheese
Penicillin production
Species of mould from Penicillium genus can be cultured in industrial fermenters - deep tank fermentation
Extraction an purification of the product produces large volumes of the drug for therapeutic use
Insulin production
Large scale production of human insulin can be carried out using biotechnology
Previously, diabetics treated with pig insulin, hard to isolate, expensive, but as effective as human insulin
Recombinant DNA tech can incorporate the gene for human insulin into the genome of the bacterium, Escheriscia coli
Grown in batch fermenters, each bacteria cell expresses insulin
Releases into the batch medium and purified
Mycoprotein (Quorn)
Mycoprotein is a meat substitute product used to make vegetarian, meat-like products
like burgers and sausages.
• Mycoprotein is low-fat and high in fibre
• This could play a part in ensuring that a growing human population eats enough
protein.
• The microorganism used is Fusarium venenatum, a filamentous fungus.
• A source of glucose is added to the tank.
• Oxygen is also supplied to ensure aerobic respiration can occur, which yields maximal
growth of hyphae (the part that forms the meat-like material).
• Nitrogen is introduced in the form of ammonia.
• The product in mycoprotein is the fungus itself, rather than a substance produced by
microorganisms.
• This is known as single cell protein (SCP). The microorganism is used directly as food)
Bioremediation
Humans can contaminate land and water with toxic substances through their activity.
• Remediating this land can remove the pollutants and restore the land to its natural state.
• Examples are oil spills, industrial accidents, acidic damage from mining and cleanup of crime scenes.
• Many bioremediation techniques rely on oxidative digestion of pollutants.
• Bioventing - a process which allows oxygen to reach the contaminants.
– Naturally occurring microorganisms perform aerobic digestion of the contaminants and release non-polluting products.
• Biostimulation also relies on naturally occurring microorganisms but adds nutrients that promote microbial
digestion of pollutants.
• Genetic engineering has been trialled to create microorganisms that are capable of bioremediation.
• Examples are Pseudomonas putida and Dechloromonas aromatica which remove pollutants from water
Advantages and disadvantages of using microorganisms to make food
Advantages:
Microorganisms used to make single-cell protein can be grown using many different organic substrates, including waste materials - molasses - getting rid of waste products
Microorganisms can be grown quickly, easily and cheaply. Production costs are low - simple growth requirements, can be grown on waste products and less land required in comparison to growing crops
Can be cultures anywhere if you have the right equipment- food source could be readily produced in places where growing crops band rearing livestock is difficult
Disadvantages:
Aseptic technique must be used - conditions needed to grow desire microorganism are also ideal for other microorganisms- lots of effort goes into making sure that the food doesn’t get contaminated with unwanted bacteria- dangerous or spoil the food
People may not like the idea of eating food that has been grown using waste products
Singe-cell protein doesn’t have the same texture or flavour as meat
What is a culture
A population of one type of microorganism that has been grown under controlled conditions
Brown in large stainless steel vats called fermenters or fermentation vessels
Batch fermentation
Where microorganisms are brown in individual batches in a fermentation vessel - when one culture ends, it’s removed and a different batch of microorganisms is grown (closed culture)
Continuous fermentation
Microorganisms are continuously grown in a fermentation vessel without stopping
Nutrients are put in and waste products taken out at a constant rate
Needs to be incredibly sterile or will ruin all the microorganisms
Production of penicillin via batch fermentation
- Penicillium mold produces the antibiotic penicillin
- Scientists grow mold in deep batch fermenters by adding sugar and other key ingredients
- Scientists separate the penicillin from the mold
- Penicillin is purified for use as an antibiotic medicine
Evaluating batch culture
- requirements are added and left to ferment
- easy, minimum attention required
- once sterilised, can be used for variety of other reasons
- if contaminated, only singe batch lost
- inlet/outlet pipes unlikely to be blocked
- growth rate slower as nutrient levels decrease with time
- less efficient, as fermenter has “down time”
- useful for production of secondary metabolites - penicillin
Evaluating continuous culture
• Steady input of nutrients into fermenter and steady harvest from it= growth rate higher
• No ‘down time’= more efficient
• Smaller vessels can be used as output continuous so less space needed for good yield
• If contamination occurs huge volumes may be lost
• Set up can be more difficult and maintenance of growing conditions can be difficult to
maintain
• Useful for production of primary metabolites e.g. proteins/enzymes for growth
Primary metabolites
- substances produced by an organism as part of its normal growth
- produced most of the time so conc match the population size
-proteins, nucleus acids, ethanol, lactate
Secondary metabolites
-substances produced by an organisms that are not part of its normal growth
- much rarer than primary metabolites
- only be produced when microbe is well-established in the growth medium
-conc don’t match population size
- antibiotics in fungi – production in response to stress caused by competition
Standard growth curve
– Lag phase - the population size increases slowly as the microorganism
population adjusts to its new environment and gradually starts to reproduce
– Exponential/Log phase- with high availability of nutrients and plenty of space,
the population moves into exponential growth (the population doubles with
each division)
– Stationary phase occurs when the population reaches its maximum as it is
limited by resources e.g. nutrients, toxic substances. The number of
microorganisms dying equals the number being reproduced by binary fission
– Decline/death phase occurs due to lack of nutrients and death due to toxic
substance build up. Death rate exceeds reproduction rate
Aseptic technique
Any measure taken during a biotechnological process to ensure
unwanted microorganisms do not contaminate culture being
grown or products extracted
• Disinfecting the working area
• Washing hands
• Lab technicians wear clean lab coats, cover hair and wear gloves
• All equipment sterilised before and after use by heating in flame
until glowing, UV light, Autoclave (121oC for 15 minutes)
• Work carried out in fume cupboard or updraft of Bunsen burner
so air circulation carries away airborne contaminants
• Passing the neck of an open vessel through the Bunsen burner
flame once opening and again before closing
• Cultures kept closed wherever possible
Inoculating broth
- Make a suspension of the bacteria to be grown
- Mix a known volume with the sterile nutrient broth in the flask
- Stopper the flask with cotton wool to prevent contamination from the air
- Incubate at a suitable temp, shaking regularly to aerate the broth providing oxygen for the growing bacteria
