DEPATMENT OF CHEMICAL ENGINEERING
NATIONAL INSTITUTE OF TECHNOLOGY CALICUT
The Product recovery operation are also known as
downstream processing steps.
Product recovery in bioprocessing plays a vital role.
Downstream- ‘After the fermentation process’.
Primary ‘unit operations’ of Downstream
Cell recovery /removal
Secondary ‘unit operations’
The cell disruption techniques may be classified as
• Physical method
• Chemical method
The following unit operations are used for the separation
of solids :
• Foam Separation
System Type With phase
Solid-liquid Soluble Drying,
Insoluble Drying Filtration,
Liquid-liquid Soluble Distillation Chromatography
Insoluble Extraction Centrifugation
Solid-solid immiscible Selective
sievingMiscible Cell disruption
It is based on the differences in the surface activity.
It is chemical process of removing a component of a
liquid mixture using a bubbled gas and a surfactant to
collect the material.
Wastewater treatment systems often use foam
separation steps to remove solids from the water
It is also a very useful method for product recovery by
adding the precipitation agent .
The compounds from the corresponding salts or the
suspending solids which would settle down to the
This method is extensively used for product recovery
of protein isolates or protein concentrates from oil
Filtration is a physical or mechanical process to
separate solids particle from fluids.
Filtration is a technique used for two main purposes.
The first is to remove solid impurities from a liquid.
The second is to collect a desired solid from the
It is a very effective and convenient method of
separating the suspending solids from the slurries .
The fluid that pass through is called a filtrate.
Filtration is used to separate particles and fluid in a
suspension, where the fluid can be a liquid, a gas or
a supercritical fluid.
Filtration, as a physical operation is very important in
chemistry for the separation of materials of different
Filtration is also important and widely used as one of
the unit operations of chemical engineering.
Viscosity of filtrate
Area of filtering surface
Resistance of filtrate cake
Resistance of filtrate surface
Properties of slurry
Filters are divided into three main categories
1. Cake filters
2. Clarifying filters
3. Cross-flow filters
Slurries with high solid concentration are operated in
Very dilute liquids are passed through the clarifying
The cross-flow filters are used for concentrating the
solutions by using filtration technique.