Biotechnology is any process which makes use of a living organism or part of one to either make a product or perform a service.
Biotch has been used for hundreds of years e.g to make cheese, yougart, beer, microproteins...
WW1: Bacteria- clostridium acetubutyllccum was used to make acetone for explosives and butanol for rubber. The Germans also used yeast to produce glycerol (explosives)
Current uses: pharmacuticals, drugs, microphropigation, tissue culture, enzymes in food+detergent, genetically engineered organisms-> herbacide resistant crops, high nutrient crops, pharming
Why use microbes?
1. Quick growth
2. Can be genetically engineered-> just one strand of DNA makes modification easy
3. Can be used to produce pure products
4. Can grow on toxic and otherwise useless materials
5. Can grow at extreme temperatures and in any climate
6. Produce proteins+metabolites into medium for harvest
7. No ethical issues
Microbe growth curve
Lag phase-> no growth, the microbe is adjusting to its environment, switching off unnecesairy genes, working out which enzymes are nessecairy(length depends on conditions)
Log phase-> rapid multiplication, maximum growth as it is adapted and has a food source
Stationary phase-> microbes reproduction=death, no food source, waste(metabolites) build-up, open system= carrying capacity
Death phase-> higher death rate than birth, no food source, high levels of waste, closed system=extinct
Substances which are produced by the metabolism of the organism, can be useful or waste products-> waste products can be useful nutrients to other organisms
Primary metabolites->Substances produced as part of the organisms normal growth, they are produced almost continuosly, concentration gradient= population size
E.g Protein:amino acids:enzymes, Nucleic acids, Ethanol, Lactate
Secondary metabolites-> Substances which are not normally produced by the organism, much rarer, only produced once the microbe is well established, production occurs once food is gone using a waste product as its start, concentration gradient does NOT match population size
E.g Antibiotics in fungi, Codeine, Morphine
Large-scale production techniques
Batch culture Secondary metabolites
+ive-> Easy setup and maintenance
Contamination only effects very small quantities
Can be easily cleaned and therfore used for other products
Clumping doesnt occur, inlet and outlet pipes cannot be blocked
-ive-> Slow growth rate as nutrient levels fall over time
Less efficient as activity isnt constant and conditions must be recreated for evey batch
Continous culture Primary metabolites
+ive->Higher growth rate as nutrient levels are constant and at maximal levels
More effiecient as activity is constant and conditions are constantly maintiained
Continual input and output means less space is needed so relativly small vessels are used
-ive-> Difficult setup and tricky maintenance
Contamination can effect large quantities
Input and output pipes can be blocked due to clumping of cells
To make a product the enzyme and susbstrate must meet, mixing the substrate with the enzyme is the easiest method however the product must then be seperated(costly). Immobilising enzymes allows the reaction to occur without the need of seperation.
Methods of immobilising enzymes
1.Adsorption-> Enzyme is mixed with a immobilising supports(porous carbon, glass beads, clay...) with hydrophobic interactions and iconic links. Detachment is possible due to weak bonds, high reaction rates.
2.Covalent bonding-> Enzymes are covalently linked to an insoluble material(clay using a cross linking agent) Strong binding, very little enzyme leakage, only small quantities, hard to attach.
3.Entrapment-> Enzyme is trapped in a gel bead or cellulose fibre network. Active are not affeted but reaction rates are reduced as substrates have to move through the trapping barrier.
4.Membrane seperation-> Enzymes seperated from substrates by a partially permeable membrane. Enzymes on one side, substrate on the other side. Substrate molecules and products can pass across the membrane but the enzymes cannot.