Enzymes inorganic solvent their properties and reaction and application in different fields.

1. ENZYMES IN ORGANIC SOLVENT
Presented by
TIASHA CHAKRABORTY
02016001322

2. INTRODUCTION
• Enzymatic catalysis in organic solvents is a new
and rapidly growing area of enzymology.
• The first report on catalytic activity of
chymotrypsin and xanthine oxidase suspended in
non aqueous media appeared twenty years ago.
• It has been a common belief that enzymes are
not catalytically active in organic solvents.

3. PROPERTIES
• Substrate Specificity - When the medium is
substituted by an organic solvent the enzyme-
substrate binding changes affecting both substrate
specificity and activity of the catalysts.
Example - chymotrypsin
• Stereo specificity - Enzymes placed in organic
solvents retain their stereo selectivity and can be
used successfully for preparative synthesis. The
transition from water to an organic solvent as the
reaction medium, the enantioselectivity of some
enzymes changes.
Example – Lipase catalysed esterifications

4. • Structure - Enzymes in some organic solvents
exhibit activities comparable to those in water.
This indicates that their structure in these
solvents is not radically different from that in
water. Example - Protease from Lysobacter
enzymogenes suspended in anhydrous acetone
and octane was preserved, indicating that the
enzyme remains intact in these solvents.
• Thermo stability - The use of dry organic solvents
as a reaction media that significantly increases
enzyme stability and their thermostability.
Example - stability of porcine pancreatic lipase

5. APPLICATION
• Alcohol Dehydrogenase
Alcohol dehydrogenases are widely used in the
preparative production of optically active
alcohols and ketones.
The instability of dehydrogenases in aqueous
environments limit their use for large-scale
synthesis.
The use of organic solvents as media for alcohol
dehydrogenase-catalyzed reactions helps
eliminate the problem.

6. • Polyphenol Oxidase
Attempts to use polyphenol oxidase as
a practical catalyst have not been
successful due to its instability.
Polyphenol oxidase immobilized on
glass beads providing a larger surface
area, placed in chloroform, and used
as a catalyst for oxidation of a number
of phenols.
The substrate specificity of the enzyme
in chloroform was found to be similar
to that in water.

7. • Horseradish Peroxidase
Horseradish peroxidase efficiently catalyzes a
variety of oxidations in a number of different
organic solvents.
The rate of oxidation of p-anisidine with
hydrogen peroxide in toluene, ether, and
ethyl acetate is as high as 20 % of that
observed in aqueous solutions.
Due to its high activity and stability in non
aqueous media, it was found useful in a
variety of applications.
For example, it was used for the quantitative
analysis of cholesterol in toluene, variety of
polymers have been produced.

8. • Lipases modification
Lipases are used in a variety of esterification reactions
for the production of triglycerides with the desired
physical properties.
The major advantage is the product has more defined
chemical composition than that obtained by
traditional chemical processes.
The lipase is catalytically active in a variety of organic
solvents including benzene, hexane, methylene
chloride and chloroform.
Porcine pancreatic and Candida cylindracea lipases
efficiently catalyze esterification of bromopropionic
acid with butanol.

9. • Steroids, Sugars, and Sugar-Related
Compounds
The enzymatically produced sugar
alcohol esters were found to be far
superior to their chemically produced
counterparts.
Sugars are reasonably well soluble in
only few very hydrophilic organic
solvents such as pyridine, formamide,
and dimethylformamide, i.e., solvents
which are the least appropriate for
lipases.

10. CONCLUSION
• It has been demonstrated in recent years that a
variety of enzymes are catalytically active in
organic solvents.
• Due to the low water activity, enzymes are
highly thermo stable in dry organic solvents and
can be used for months without loss of activity.
• Similar to their action in aqueous solutions,
enzymes in organic solvents are substrate-
specific.

11. BIBLIOGRAPHY
• Biocatalysts for Industry -- Jonathan S_ Dordick
(auth_), Jonathan S_ Dordick (eds_) -- 1, 1991 --
Springer -- 10_1007_978-1-4757-4597-9 --
530f40822e238004d60529e3118ca99b --
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