Microbial Biotechnology and BioEthics Flashcards
Name the various applications of amino acids.
Amino acids is used in:
1. Animal feed
2. Health foods
3. Pharmaceutical precursors
4. Dietary supplements
5. Artificial sweeteners
6. Comestics
The worldwide amino acid market is -
> $20 billion
What are some amino acids that can/are made using microbial production?
proline and glutamate
What is a primary part of the production of proline using microorganisms?
Microbial production of proline is done by using the technique of amino acid overproduction.
Amino acids are used as?
- Flavour enhancers
- Supplements
- Sweeteners
- Intravenous infusions
- Industrial purposes (detergents and water purification)
- Pharmaceuticals
Why is it not metabolically wise for a microorganisms to overproduce amino acid and secrete them?
What’s the solution scientists have found to combat this?
It is not metabolically wise because overproduction creates a metabolic load that cells may not be able to control.
Finding and utilizing mutants that naturally overproduce or metabolically engineer microbes that overproduce
There are three methods that microorganisms use to control metabolic pathways. What are they?
- Feedback inhibition
- Transcription regulation
- Attenuation
Which commonly used microorganisms use all three control mechanisms?
Escherichia coli
To produce proline, the microorganism Serratia marcescens is used. Why is this used as opposed to E.coli
- E. coli has the three levels of regulations that scientist must overcome for amino acid overproduction.
- Serratia marcescens only has one mechanism to overcome and that is feedback inhibition
Give an overview on how proline is overproduced by S. marcescens.
- For proline overproduction to take place, feedback inhibition must be overcome
- This is achieved by plating Serratia marcescens on proline analogs. This caused the wild type to die and the S. marcescens with impaired/mutated feedback inhibition (FI) were able to survive
- These S. marcescens were further modified and the gene responsible for proline degradation was removed.
- Those were then grown on high salt concentration because S.marcescens used proline as an osmoprotectant.
- The cells produced 60-75 g/L of proline
- The final genes for proline biosynthesis was cloned into a plasmid that had a high copy number so more proline could be produced.
- There was a 50% increase in the proline produced
Why would the strategy used to overproduce proline not work for other amino acid production.
- the amino acids are not used as osmoprotectants
- Many amino acids are produced by branched pathways and has several points of feedback inhibition.
Name the amino acid that was first produced on an industrial scale.
Glutamate
How is glutamate produced?
- Bacteria that overproduce glutamate are isolated from the soil and belong to the corynebacterium-brevibacterium group
- C. glutamicum is used for the overproduction
- Glutamate is overproduced under certain conditions such as :
1. Biotin starvation
2. Low oxygen
What is citric acid’s primary use?
- widely used in the beverage industry as an acidulant to lower pH in beverages
- inhibit flavour development in fresh and frozen fish
How is citric acid produced?
- produced industrially by Aspergillus niger
- Overproducing A. niger strains will overproduce citric acid from glucose if given:
1. sufficient oxygen
2. media deficient in manganese
