Precipitation

secondary metabolite Precipitation process

1. Precipitation
Dr. Deepak Bhusare
Department of Microbiology
DB, ACS College, Bhokar.

2. Introduction
•Proteinprecipitationiswidelyusedindownstreamprocessingofbiological
products.
•Hydrophilicandhydrophobicaminoacidresiduesontheprotein'ssurface.
•Highhydrophobicaminoacidhavelowsolubilityinanaqueoussolvent.
•Chargedandpolarsurfaceresiduesinteractwithionicgroupsinthesolventand
increasethesolubilityofaprotein.

3. Protein precipitation
•Nucleationphase: submicroscopic sized protein aggregates, or particles,
are generated.
•Particle size 0.1 µm to 10 µm.

4. Solvents Precipitation
•EthanolorMethanoltoasolutionmaycauseproteinsinthesolution
toprecipitate.
•theproteinscanaggregatebyattractiveelectrostaticanddipoleforces.
•Importantparameters:Temperaturelessthan0°Cto
avoiddenaturation,pHandproteinconcentrationinsolution

5. Non-ionic hydrophilic polymers Precipitation
•Polymers:DextransandPolyethyleneGlycols,arefrequentlyusedto
precipitateproteins.
•Attractwatermoleculesawayfromthesolvationlayeraroundthe
protein.
•Thisincreasestheprotein–proteininteractionsandenhances
precipitation

6. Isoelectric (pI) precipitation
•AthighpIproteinpossessnegativecharge.
•AtlowpIproteinpossesspositivecharge.
•ThepIofmostproteinsisinthepHrangeof4–6
•Mineralacids,suchashydrochloricandsulfuricacidareusedas
precipitants

7. Thank You