Understanding the Options

Microbial Cell Culture Clarification:
Expressed Protein

Expressed Protein Clarification: Cell Removal

• Separation of cells from fermenter broth and product recovery in filtrate fluid
• High solids content in feed stream, which makes centrifugation a viable option
• Feed stream quality can vary depending upon cell type and culture conditions

Recommended Filter	Filter Characteristics
Depth Filtration Double-layer Millistak+ HC Filters (Grade C0HC or D0HC) Disc Filters Pod Filters	Better suited for small to medium size fermenters up to 1,000 L or larger volumes with low usage rates of less than 10 batches/year Double-layer design enhances loading capacity and filtrate quality Unique configuration allows compression of multiple process steps into one, lowering overall filtration costs Selection of C0HC or D0HC media grade depends on particle size distribution in feed solution. Choice should be based upon small-scale testing.
TFF with Microfiltration Membrane Prostak Open-Channel Modules with 0.22 µm or 0.1 µm Durapore Membrane	Open-channel design ideal for fluids containing high cell densities and solids High flux at low transmembrane pressure allows volume reduction as fluid gets concentrated Robust construction for multiple use Validated for multiple SIP cycles Selection of 0.22 µm or 0.1 µm membrane depends on particle size distribution in feed solution. Choice should be based upon small-scale testing.

Sterile Filtration: Bioburden Reduction

• Reduces bioburden
• Protects downstream chromatography and UF/DF steps
• Maintains yield of dilute protein and preserves purity
• Sterilizing-grade filtration required

Recommended Filter

Filter Characteristics

Single-layer Durapore 0.22 µm PVDF Filters Cartridge Filters Optiseal Cartridge Filters Opticap Capsule Filters Optiseal Capsule Fitlers

Sterilizing-grade PVDF membrane won’t bind valuable protein 100% Integrity tested to ensure proven performance Can be integrity testable on-site Although 0.22 µm is typical for this application, Durapore filters are available in several pore sizes and, in single-layer or multi-layer configurations to accommodate the needs of each user, the degree of protection required for the downstream process and the plugging characteristics of the fluid. Choice should be based on small-scale testing.