Biotechnology Flashcards
What is biotechnology?
The use of living organisms or their compounds to synthesise, breakdown or transform materials for human use
Biotechnology in brewing
Yeast ferment sugars anaerobically to produce ethanol and CO2 to make alcoholic drinks
Biotechnology in baking
The carbon dioxide produced by yeast during sugar fermentation makes bread dough rise
Biotechnology in cheese making
Chymosin coagulates milk into curds
Bacteria and moulds contribute to acidification, thickening and flavour
Biotechnology in yoghurt
Certain bacteria ferment lactose into lactic acid which sours and solidifies milk into yoghurt
Biotechnology in medicine
Bioengineered fungi and bacteria produce drugs, like penicillin and insulin for diabetes treatment
Biotechnology in bioremediation
Microbes speed up degradation of pollutants like oil spills
How is penicillin made?
- Small fermenters with constant stirring to ensure high oxygen levels
- A nutrient-rich medium for optimal growth
- A buffer to keep stable pH at around 6.5
- A constant temperature of about 25-27 for ideal fungal activity
2 main approaches to bioremediation
Use natural organisms - uses microbes ability to digest organic materials
Develop genetically modified organisms - uses bacteria to break down specific pollutants
Why are microorganisms cultured?
To generate biomass of the microorganisms
To manufacture compounds the microbes synthesise
What are primary and secondary metabolites?
Primary metabolites - substances that are produced in essential processes for normal microbial function
Secondary metabolites - substances produced in non-essential processes
What are bioreactors?
Used for large, commercial-scale production of microbial cultures
Large fermentation tanks that are optimised for microbial growth
What are the components of a bioreactor?
Metal or plastic tank with inputs and outputs for liquids and gases
Paddles for mixing culture for even distributing food oxygen and temperature
Probes to monitor pH, temperature and dissolved oxygen
Ports for adding ingredients
Sterilisation system
How are nutrients controlled in bioreactors and why?
Fresh medium circulated by paddles
As population increases, demand for nutrients increase, so microbes need constant supply
How is temperature controlled in bioreactors and why?
Heating/cooling jacket surrounds the vessel
Too low temp means enzymes wont work
Too high temp means enzymes denature
How pH controlled in bioreactors and why?
Monitored by pH probe and automaticall adjusted by adding acid/base
Increased CO2 reduces pH which inhibits enzyme activity
How are oxygen levels controlled in bioreactors and why?
Sterile air pumped in
As population size increases the demand for oxygen increases for aerobic respiration
How is waste controlled in bioreactors and why?
Steam sterilation and removal of waste products
Unwanted microbes creates competition
Build of of waste can kill bacteria
What is batch fermentation?
Microbes are grown in a fixed volume in individual batches until nutrients deplete and waste accumulates
What is continuous fermentation?
Continuously supplying fresh nutrients and removing the culture broth
This maintains growth of culture
What are the 4 stages in microbial growth curve?
Lag phase - slow growth, adapt to environment
Exponential phase - rapid division, maximum growth rate
Stationary phase - cell growth = cell death
Death phase - cell death > cell growth
How can factors affecting microbial growth be investigated?
Temperature - incubate duplicate plates at different temperatures
pH - add buffer solution to agar
Nutrient availability - prepare agar with different nutrient concentrations
What are the main methods of enzyme immobilization?
Binding - enzymes bound to insoluble materials by covalent or ionic bonds
Adsorption - enzymes adsorbed onto the surface of insoluble material
Entrapment - Enzymes trapped in matrix
Encapsulation - enzymes isolated by partially permeable membrane
Advantages of using immobilised enzymes
Cost effective - can reuse enzymes
Product purity - enzyme-free products produced
Improved stability - more tolerant to temp and pH change
Disadvantages of using immobilized enzymes
Higher initial costs - materials and bioreactors are expensive
Reduced enzyme activity
Technical problems
