Biotechnology - Summary notes OCR
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Biotechnology
Biotechnology = the industrial use of living organisms to produce food, drugs, and other products.
Casein = milk protein.
Rennet = contains the enzyme chymosin, which coagulates the milk (chymosin was originally extracted from the
lining of calves’ stomachs, but now extracted from genetically modified yeast cells.)
Lac operon =
Why do we use microorganisms?
1) Cheap and easy to grow.
2) Low Temperature needed compared to chemically engineering (saves fuel, reduces cost)
3) Pressure – can take place at lower pressure so safer and cheaper than other chemical reactions.
4) Not dependent on climate – can take place anywhere in the world.
5) MOOS can be fed with by-products of other industrial processes.
6) MOOS have a short life cycle and reproduce quickly – products can be made quickly.
Ways we can use microorganisms.
Alcohol SCP
• Product of anaerobic respiration of yeast. • Direct food production.
• S. Cerevisiae. • Fungus à Fusarium Venenatum
• Grape skin acts as yeast • Fungal protein = mycoprotein
• Sugars in grapes act as the respirates of yeast. • Increasing potential to make it more meat
• Ale – germinating barley used à starch textured by using new microorganisms like
converted to maltose, respired by yeast. Scytalidium.
Yoghurt Cheese
• Yoghurt is milk that’s been fermented. • Milk pre-treated with bacteria that produce
• Lactobacillus bulgaricus and Streptococcus lactic acid from lactose.
Thermophiles. • Once acidified, mixed with rennet.
• Bacteria convert lactose to lactic acid. • Rennet coagulates the mixture, in the presence
• Acidity denatures the milk protein (casein) of calcium ions.
causing coagulation. • Kappa casein breaks down, casein insoluble.
• Probiotics can then be added. • Casein precipitates and then curd is pressed
into moulds.
Steps of making alcohol
1) Malting à barley germinates, producing enzymes that breaks down starch molecules down to sugars which
yeast can use. Seeds are killed by slow heating but enzyme activity is retained to produce malt.
2) Mashing à malt is mixed with hot water and enzymes break down starches to produce wort. Hops added
for flavour and antiseptic qualities, wort is then sterilised and cooled.
3) Fermentation à wort inoculated with yeast, temperarture is maintained for optimum anaerobic respiration
(fermentation) and eventually the yeast is inhibited by falling pH, a build up of ethanol and lack of oxygen.
4) Maturation à Beer is conditioned for 4-29 days at temperatures of 2-6’C in tanks.
5) Finishing à beer is filtered, pastuerised and then bottled with the addition of carbon dioxide.
Bioremediation
Bioremediation = microorganisms are used to break down pollutants and contaminants in the soil or water.
• USING NATURAL ORGANISMS à many organisms break down organic material producing carbon dioxide
and water, if the natural organisms are supported they will break down and neutralise many contaminants.
• GENETICALLY MODIFIED ORGANISMS à scientists are trying to develop GM bacteria that break down
contaminants that they would not naturally encounter e.g., bacteria that remove mercury.
, Pros of SCP Cons of SCP
• No animal welfare issues • Protein must be purified to ensure it is not
• Biomass has very high protein content contaminated.
• Quick and cheap • Infection – conditions of MOO is also ideal for
• Production can be increased or decreased pathogens.
according to demand • Some people won’t want to eat fungi.
• Protein content high • Palatability – texture and taste not to people’s
• Not dependent on seasonal variation standards.
• No cholesterol or fat • Amino acid profile is different to animals – lacks
• Production is faster than animal protein methionine.
• Nutrient requirements are usually simple and • Nucleic acids may be present – must be
cheap. removed.
Fermentation vessels
There are two methods for culturing microorganisms:
1) Batch fermentation à where MOOS are grown in individual batches in a fermentation vessel – when one
culture ends it is removed and then a different batch of MOOS is grown in the vessel. (CLOSED CULTURE)
2) Continuous fermentation à where MOOS are continually grown in fermentation vessel without stopping.
Nutrients put in and waste products taken out at a constant rate.
Primary metabolites = normal growth, normal conditions e.g., SCP Quorn, alcohol.
Secondary metabolites = happen in response to specific conditions e.g., Stress – causes competition.
RUN, STOP, CLEAN, RUN, STOP, CLEAN………………. CONSTANT…….
Only add nutrients at start Keep adding nutrients
Cheaper sterilisation
More expensive sterilisation as more often so increased Regular product removal.
cost.
(-) ISSUE à contamination = loss of lots of moneys.
Factor How its regulated How it maximises yield
pH
Monitored by pH probe and kept at optimum level Allows enzymes to work efficiently,
so ROR as high as possible.
Temperature Kept constant by water jacket that surrounds
vessel.
Access to nutrients Paddles circulate fresh nutrient medium around Ensures MOOS always have access
vessel to nutrients.
Volume of oxygen Sterile air pumped into vessel when needed. Makes sure MOOS always have
oxygen for respiration.
Vessel kept sterile Superheated steam sterilises vessel after each use. Kills unwanted organisms that may
cause competition.
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