Temp P2

Question 1

Culturing micoorganims via inoculating broth

Answer 1

Culturing micoorganims via inoculating broth:
-Make suspension of bacteria to be grown
-Mix known volume with the sterile nutrient broth
-Stopper the flask with cotton wool to prevent contamination with the air
-Incubate at suitable temperature, shaking regularly to aerate the broth, providing oxygen for the bacteria

Question 2

Culturing microorganisms via inoculating agar

Answer 2

Culturing microorganisms via inoculating agar:
-Sterile inoculating loop held in a bunsen flame
-Dip loop into bacterial suspension, keeping agar surface intact
-Replace petri dish lid (not entirely sealed to allow some oxygen in, preventing growth of anaerobic bacteria)

Question 3

Stages of bacterial growth curve

Answer 3

Stages of bacterial growth curve:
-Lag phase = adapting to their environment
-Exponential/log phase = rate is at maximum
-Stationery phase = total growth is zero - new cells produced by binary fission in cancelled out
-Death stage = ceased reproduction and cells die

Question 4

Batch fermentation

Answer 4

Batch fermentation:
-Microorganisms incoluated into a fixed volume of medium
-Nutrients used up, new biomass and waste products build up
-Growth ceases at the stationery phase and microorganisms carry out biochemical changes to form desired end produced
-Products stop before death phase and are harvested

Question 5

Continuous culture

Answer 5

Continuous culture:
-Microorganisms inoculated in sterile medium
-Medium added continously once reached exponential growth
-Culture broth continuously removed and volume kept constant
-used mostly for single-celled protein and some water treatments

Question 6

Methods of immobilising enzymes

Answer 6

Methods of immobilising enzymes:
-Absorption -> held in place by ionic interactions
-Absorption -> attached to an inorganic carrier eg cellulose
-Entrapment -> in matrix
-Entrapment -> encapsulisation in a membrane

Question 7

Immobolised enzymes examples

Answer 7

Immobolised enzymes examples:
-Lactase (lactose -> glucose)
-Glucose isomerase (glucose -> fructose)

Question 8

Effeciency of energy transfer calculation

Answer 8

Efficiency of energy transfer calculation = net productivity/total energy received x 100