Bioreactors Flashcards
What are bioreactors?
Bioreactor is a system in which a biological conversion is carried out.
What are the challenges of bioreactors?
- Mutation
- Contamination
- Change in environment
- Microbial growth
- Metabolite production
What are the advantages and disadvantages of bioreactors?
Advantages:
- Production of complex organic molecules
- Higher yields
- Operate at lower temperatures and near neutral pH
- Greater specificity
- Exclusive production of isomeric compounds
Disadvantages:
- Easily contaminated
- Product will be present as a complex mixture
- Necessary for proper handling of effluent
- Slow.
How can bioreactors be classified?
By the method of fermentation:
- Submerged fermentation: Fermentation under high water activity medium
- Solid state fermentation: Production of bioproducts under low moisture content.
By the mode of Bioreactions:
- Batch bioreactors
- fed-batch bioreactors
- Continuous bioreactors.
What are the parameters to be controlled in bioreactors?
- Temperature
- pH
- Substrate
- Water availability
- Oxygen
- Product and byproduct removal
What are the methods of sterilization of fermentation medium?
- High temperature
- Membrane filtration
- Irradiation
What are the methods of sterilizing air for aerobic fermentation?
- Pre-filter: Removes dust, oil droplets and moisture.
- Absolute filter to remove bacteria and virus
What is the importance of mixing in bioreactors?
- To ensure the uniform distribution of nutrients and/or dissolved oxygen to improve productivity, yield and product distribution.
What are the advantages and disadvantages of batch bioreactors?
Advantages:
- Reduced risk of contamination and mutation
- Lower capital investment
Disadvantages:
- Requires frequent sterilization
- Greater expense in preparing subcultures for inoculations
- Higher labor and processing cost
What are the advantages and disadvantages of continuous bioreactors?
Advantages:
- Increased potential for automation
- Reduced labor expense
- Continuous productivity
- Decrease toxicity risks to staff
- Reduced stress on instruments due to lower frequency of sterilization
Disadvantages:
- Uniformity of raw material is necessary
- High investment costs in equipment
- Higher risk of contamination and cell mutation.
What is the difference between fed-batch bioreactions and continuous bioreactions? Describe its advantages,
The effluent is not removed continuously from the fermenter in fed-batch bioreactions.
Advantages:
- Substrate can be manipulated to optimize product formation
- Less effect from contamination compared to continuous bioreactions.
What are biosensors?
A device that detects, transmits and records information regarding biochemical changes. It is used for monitoring bioreactions.
What are the there basic processes of formation of bioreaction products?
- Processes in which cells produces extracellular products
- Processes that produce cell mass
- Processes that modify a compound that is added to the fermentation process (biotransformation).
What are some processes used to recover and purify fermented products?
- Cell separation (centrifugation, settling, dead-end filtration)
- Cell disruption (high pressure homogenization)
- Clarification of extract (Centrifugation, extraction)
- Enrichment (ultrafiltration, partition, precipitation)
- High resolution techniques (Chromatography, electrophoresis etc)
- Concentration (Ultrafiltration, freeze drying, spray drying etc)
What are some parts of a bioreactor? State its use.
BIPRISM Water Outlet
- Baffles: Mixing (create turbulence and minimize vortex)
- Impeller: Mixing
- Probes: In-line measurement of process
- Rakes: Suppresses foam.
- Inlets; Inoculation, nutrients feeding, pH adjustments, antifoaming agent, air
- Sparger: Oxygen supply
- Motor: Drives the movement of the impeller
- Water jacket: Temperature control
- Outlets: Air exhaust, sampling port
