6.2.1 Biotechnology Flashcards
what is biotechnology
the industrial use of living organisms to produce food, drugs and other product s
what is used in biotechnology and why?
microorganisms
- ideal growth conditions can be easily created - microorganisms will generally grow successfully as long as they have the right nutrients, temperature, pH, moisture levels and availability of gases
- because of their short life cycle, they grow rapidly under the right conditions, so products can be made quickly
- they can be grown on a range of inexpensive materials - this makes them economical to use
- they can be gown at any time of the year
enzymes also used
biotechnology - brewing
to make beer, yeast is added to a type of grain (barley) and other ingredients
the yeast respires anaerobically using the glucose from the grain and produces ethanol (and co2)
- fermentation
biotechnology - baking
yeast makes bread rise due to the co2 produced during fermentation
biotechnology - cheese making
old way - used to rely on rennet from the lining a claves stomachs, contains enzyme chymosin which clots milk
new way - chymosin can be obtained from genetically modified yeast cells
also involves lactic acid bacteria –> convert lactose in milk to latic acid which turns it sour and contributes to it solidifying
biotechnology - yoghurt production
uses lactic acid bacteria to clot milk so it thickens
then any flavours and colours are added
biotechnology - penicillin production
in times of stress, fungi from the penicillium genus produce an antibody, penicillin to stop bacteria from growing and competing for resources
one of the most common antibiotics used in medicine and is produced on a massive scale
the fungus is grown under stress in industrial fermenters and the penicillin produced is collected and processed to be used in medicine
biotechnology - insulin production
insulin is a hormone crucial for treating people with type 1 diabetes
insulin is made by genetically modified bacteria, which have had the gene for human insulin production inserted into their DNA
these bacteria are grown in an industrial fermenter on a massive scale and the insulin produced is collected and purified
biotechnology - bioremediation
using organisms to remove pollutants, oil and pesticides from contaminated sites
most commonly pollutant-removing bacteria that occur naturally at a site are provided with extra nutrients and enhanced growing conditions to allow them in multiply and thrive
these bacteria break down the pollutants into less harmful products, cleaning up the area
eg. oil spills
using microorganisms in food production - why?
microorganisms can also be grown as a source of protein (single celled protein) which can act as a valuable food source for humans and other animals
- quorn
advantages of using microorganisms in food production
- microorganisms used to make single cell protein can be grown using many different organic substances, including waste materials - a way of getting rid of waste products
- can be grown quickly, easily, and cheaply
- production costs are low because microorganisms have simple growth requirements
- can be grown on waste products
- less land required in comparison to growing crops - can be cultured anywhere if you have right equipment - means a food source could be readily produced in places where growing crops and rearing livestock is difficult. could help tackle malnutrition
- single cell protein is often considered a healthier alternative to animal protein
disadvantages of using microorganisms in food production
- conditions needed to grow the desired microorganisms are also ideal for other organisms - a lot of effort has to go into making sure the food doesn’t get contaminated with unwanted bacteria which could be dangerous to humans or spoil the food
- people may not like the idea of eating food that has been grown using waste products
- single cell protein doesn’t have the same texture or flavour as real meat
- is single cell protein is consumed in high quantities, health problems caused due to high levels of uric acid release when large amounts of amino acids are broken down
what are microorganisms grown in?
fermentation vessels
culturing microorganisms - two ways
batch
continuous
batch fermentation
microorganisms are grown in individual batches in a fermentation vessel
when one culture ends it is removed
then a different batch is grown in the vessel
continuous fermentation
where microorganisms are continually grown in a fermentation vessel without stopping
nutrients are put in and waste products are taken out at a constant rate
how can you maximise yield of desirable products?
conditions inside the fermentation vessel kept at optimum for growth
conditions in fermentation vessel favourable - pH
constatly mointered by a pH probe and kept at the optimum level
allow enzymes to work efficiently so the rate of reaction is kept as high as possible
conditions in fermentation vessel favourable - temperature
kept constant by a water jacket surrounding fermentation vessel
allow enzymes to work efficiently so the rate of reaction is kept as high as possible
conditions in fermentation vessel favourable - access to nutrients
paddles constantly circulate fresh nutrient medium around the vessel
ensures that the microorganisms always have access to their required nutrients
conditions in fermentation vessel favourable - volume of oxygen
sterile air is pumped into the vessel when needed
makes sure that the microorganism always have oxyegn for respiration
conditions in fermentation vessel favourable - vessel kept sterile
superheated steam sterilises the vessel after each use
kills any unwanted organisms that may compete with the ones being cultured
what are the phases of a growth curve? - batch
- lag
- exponential
- stationary
- decline
growth curve - lag phase
the population size increases slowly
microoorganisms have to make enzymes and other molecules before they can reproduce
reproduction rate is low
growth curve - exponential phase
population size increases quickly
culture contitions most favourable for reproduction (lots of food and little competition)
no. of organisms doubles at regular intervals
growth curve - stationary phase
pop. size stays level
death rate = growth rate
microorganisms die because not enough food and waste products build up
growth curve - decline phase
pop. size falls
death rate greater than reproduction rate
food scarce and waste products at toxic levels
growth curve - how many individuals present in a population after a certain number of division?
N = N0 x 2^n
number of individuals prestent = initial number of cells x 2^n (where n=no. of divisions)
double at regular intervals
how do you culture microorganisms?
- cultures can be grown in a lab
- on a agar plate - a sterile perti dish containing agar jelly
- microorganisms are transferred to the plate from a sample using a sterile wire incolulation loop and spreader
- incybate the plates and allow the microorganisms to grow
- nutrients can be added to the agar to help improve the growing conditions
aseptic techniques - why?
to prevent contamination by unwanted organisms which may affect growth
in laboratory experiments - imprecise results and may to hazourdous to health
industrial scale - costly as entire cultures may have to be thrown away
aseptic techniques - what?
- regurarly disinfect work surfaces
- work near a bunsen flame –> microorganisms in air drawn away
- sterilse the instrument used to transfer cultures before and after each use
- wire inoculation loop by passing it through a hot bunsen flame - minimise time agar plate is open - put lid on as soon as possible —> reduces chance of airborne microorganisms contaminating the culture (incoulation cabinet)
- sterilise all glassware before and after use (eg. autoclave)
- lab coat, gloves, hair ties back
factors affecting growth rate - investigation
- put a set vol. of sample on to an agar plate
- spread broth across entire surface of the agar using a sterile spreader
- put the lid on the agar plate and tape it shut
- repeat so have 6 plates
change variable investigating - have negative controls with no bacteria on plate
- upside down so no condensation falls on bacteria!!!
- leave all the plates the same amount of time then observe the results
- count the no. of colonies that have formed on each plate - record in a table
- work out mean no. of colonies
factors affecting growth rate - temperature
incubate at different temperatures
2 at each temp. w/ a control
factors affecting growth rate - pH
adding buffers at different pH levels to broth
factors affecting growth rate - nutrient availability
using different preperations of agar
what is too many colonies to count?
serial diution
- more manageable no. of colonies
how can you investigate growth of microorganisms in broth
spectrophotometer
- measures cloudiness (turbidity) of broth
what are immobilised enzymes
when enzymes that are attatched to an insoluble material so they cant become fixed with the products
how are enzymes immobilised?
- encapsulation in jelly like alginate beads, which act as a semi-permeable membrane
- trapped in a silica gel matrix
- covalently bonded to cellulose or collagen fibres
how are immobilised enzymes used in industry
the substrate soltuion is run through a column of immobilised enzymes
the active sites of the enzymes are still available to catalyse the reaction but the solution flowing out of the column will only contain the desired product
advantages of using immobilised enzymes
- column of immobilised enzymes can be washed and resused - this reduces costs of running a reaction on an industrial scale because don’t have to keep buying new enzymes
- product isn’t mixed with enzymes - no money or time is spent separating them out
- immobalised enzymes are more stable than free enzymes - less likely to denatre in high temps or extreme pHs
disadvantages of using immobilised enzymes
- extra equipment is required, which can be expensive to buy
- immobilised enzymes are more expensive than free enzymes so not always economical for smaller-scale production
- immobilisation of enzymes can lead to a reduction in the enzyme activity because they can’t freely mix with their substrate
uses of immobilised enzymes - conversion of lactose
to glucose and galactose
some people are unable to digest lactose (a sugar in milk) –> they don’t have the enzyme lactase
lactatse breaks down lactose into glucose and galatose by hydrolysis
industrially, fresh milk can be passed over immobalised enzymes to produce lactose free milk for use in the production of lactose-free dairy products
uses of immobilised enzymes - penicillins
penicillin is a useful antibiotic, but some bacteria have become penicillin resistant
semi-synthetic peneicillins can now be produced - have the same antibiotic properties as natural penicillin, but are effective against penicillin resistant bacteria
immobalised penicillin acylase enzymes is ised in their production
uses of immobilised enzymes - conversion of dextrins
to glucose
glucose and glucose syrup are used in massive amounts in industry - food industry to sweeten and thicken foods
gluose can be derived from starchy foods, corn and potatoes, using immobilised enzymes
starch breaks down into dexrins, which are broken down into glucose by the immobilised enzyme glucoamylase
uses of immobilised enzymes - conversion of glucose
to fructose
fructose is much sweeter than glucose
used as a sweetener in food - less is needed for the same level of sweetness
immobalised glucose isomerase is used
uses of immobilised enzymes - production of pure samples of L-amino acids
amino acids have two isomers - L or D
most amino acids utilised by the body need to be in L form
scientists able to chemically synthesis amino acids, but end up with a mix of L and D, the enzyme aminoacylase separates then
immobilised aminoacylase is used for the industrial production of animal and human food, and dietary supplements
