Tangential Flow Filtration: Membrane Types and Process Parameters

Tangential Flow Filtration [TFF] is used for clarifying, concentrating and purifying proteins.

Filtration is a pressure driven separation process that uses a membrane to separate components in liquid solution or suspension based on size and charge difference.

Types of Membrane Filtration

1. Normal Flow Filtration - Dead End Filtration

2. Tangential Flow Filtration - Cross Flow Filtration

Tangential Flow Filtration:

Tangential Flow Filtration is divided into categories based on the size of the components being separated.

Generally membrane pore size is given as micron value, particles sized above this value will be retained.

Types of TFF

1. Micro Filtration 

2. Ultra Filtration

Ultra Filtration is catagorized into two 

• Virus Filtration
• High Performance Tangential Flow Filtration

Process Goals

1. Final Product Concentration
2. Feed Volume Reduction
3. Extent of Buffer Exchange
4. Contaminant Removal Specification

Primary Protein Processing Goals

1. High Product Yield
2. High Product Quality
3. High Product Purity
4. Controlled Bioburden

Membranes

• Polyethersulfone (PES)
• Regenerated Cellulose

Types of Membranes

1. Flat Plate
2. Spiral Wound
3. Hollow Fiber

Key Parameters to Optimize

1. Cross Flow Rate
2. Transmembrane Pressure
3. Filtrate Control
4. Membrane Area
5. Diafiltration Design

Factors affecting Product Yield

These are the four contribution of product loss during Tangential FLow Filtration

1. Retention Loss
2. Adsorption Loss
3. Solubility Loss
4. Unrecoverable hold up volume loss

Factors affecting Product Quality

Quality of product is compromised due to aggregation or denaturation caused by

1. Micro cavitation
2. Air-Liquid Interface
3. High Protein Concentration
4. Temperature Effects