Synthesis of Chiral Alcohol through Enzymatic Reduction Flashcards
what are the general requirements for a cell undergoing metabolism?
food, water, heat
how are the basic needs of metabolism met in the lab?
sugar, aqueous media, incubator
why is it necessary to wait 15 min before adding substrate?
yeast is dormant and must be hydrated to wake up and then begin the metabolic process to make the product
if travel across the membrane reduces yield, how can it be optimized?
adding salt to increase [ ] gradient, forces water in, rupturing the cell, which releases the contents
what separation technique is used to separate an organic compound from water?
l-l extraction with an organic solvent
a large addition of salt impacts isolation process in 2 ways
- killing cell releases product, but stops production
2. killing cell stops side reaction
what is the key pitfall of using whole-cell biotransformation?
all enzyme systems of cell are present, so side reactions will occur
how does a polarimeter work?
passes monochromatic light through a polarizing filter, causing it to become a single beam of plane-polarized light
Then goes through sample, which rotates the beam, and a second filter determines the angle of rotation
what are the variables that must be addressed in determining optical rotation?
- concentration
- path length
- temperature
- wavelength
what is the difference between observed and specific rotation?
observed is the value read off the instrument. Specific accounts for pathlength and concentration
what are the 7 sources of error in this lab?
- transfers
- aqueous in l-l
- drying agent
- potential volatility, loss during distillation
- incomplete reactions due to equilibrium
- side reaction
- loss to alumina
why might the optical purity found in this lab be lower than the literature?
more oxygen during fermentation
why is celite used in this lab?
it allows for filtration of particless so small, they would pass through normal filter paper
what substances in reaction mixture could be responsible for an emulsion during the work-up?
left over cell components, products of metabolism, such as fatty acids, amino acids, glycols
what are the side reactions of this process?
all metabolic reactions, such as glycolysis, pyruvate processing, synthesis of amino and fatty acids
