22.7Culturing microorganisms an industrial scale Flashcards
What are primary metabolites
Substances that are wanted which are formed as an essential part of the normal functioning of a microorganism
What are secondary metabolites
Organisms produce substances which are not essential for growth but are still used by cells
Organism wouldnt suffer without them
What are teh 2 main ways of growing microorganisms
Batch fermentation
Continuous fermentation
What are teh first 2 stages of batch fermentation
Microorganisms are inoculated into a fixed volume of medium
Growth will then begin to take place and the nutrients are used up and both new biomass and waste products build up
What happens in batch fermentation when the culture reaches the stationary phase
Overall growth stops but microorganisms often carry out biochemical changes to form desired end product
The process is stopped before the death phase and the products are harvested
What happens in continuous fermentation
Microorganisms are inoculated into sterile nutrient medium and start to grow
Sterile nutrient medium is added continuously to culture once it reaches exponential point of growth
And teh culture broth is continuously removed
This keeps the culture volume in the bioreactor constant
How do we control bioreactors and why is it important
Important to maximise the yield of products required
Control - Temp Nutrients and oxygen Mixing things up Asepsis - sealed in aseptic units