 |
 |
||||||||
 |
 |
 |
|
||||||
 |
 |
 |
|
||||||
 |
|
||||||||
 |
|
||||||||
 |
 |
 |
 |
 |
|
||||
 Some
present-day applications of biocatalysis in industry
Making use of milder conditions Enzymes are very active catalysts, which means that reactions can be carried out under much milder conditions than with conventional chemical processes. This is a big advantage in the production of propenamide. If a naturally occurring enzyme is not exactly right it can be genetically engineered to give better properties. The Nitto chemical company in Japan used chemical mutagenesis methods to improve the activity of an enzyme by a factor of 3000 and used it in the manufacture of propeneamide. Click for details of the procedure.
Making use of selectivity Enzymes stereo-selective. An esterase given the opportunity to hydrolyse a mixture of chiral esters can hydrolyses one enantiomer faster than its mirror image giving a chiral acid and leaving a chiral ester which can be recovered, racemised and recycled
   +
Using
selectivity to avoid unwanted by-products
A condensation reaction can create an amide link by the reaction of an amino group and a hydroxyl group.
If
the starting material is a racemic mixture an enzyme will catalyse the
reaction of only one isomer to give the desired product leaving the other
isomer to be racemised again and recycled.
This technique is used in the manufacture of aspartame because while one isomer is sweet the other is extremely bitter - not something you would want in a sweetener!  
|