Single-pass filtration systems and processes
The present invention provides, in various embodiments, hybrid single-pass tangential flow filtration assemblies, disposable single-pass tangential flow filtration assemblies, scalable single-pass tangential flow filtration assemblies and adaptable modular single-pass tangential flow filtration assemblies. In other embodiments, the invention relates to processes for recovering proteins from the surface of a filtration membrane in a single-pass tangential flow filtration assembly and for cleaning a tangential flow filtration assembly. In additional embodiments, the invention provides methods of increasing the processing capacity of a single-pass tangential flow filtration assembly.
1. A process for cleaning a tangential flow filtration (TFF) assembly, consisting essentially of:
a) flushing a liquid that lacks cleaning agent through a feed channel in a TFF assembly comprising two or more TFF cassettes to displace product from the surfaces of filtration membranes in the assembly to the feed channel;
b) flushing the feed channel in the assembly with a cleaning solution comprising a cleaning agent, thereby removing the displaced product from the feed channel;
c) stopping the flow of liquid through the assembly to allow the cleaning agent to reach the internal surfaces of the assembly and diffuse into fouling deposits on the filtration membrane for about 30 to about 60 minutes, thereby dissolving the fouling deposits; and
d) flushing the assembly with a liquid that lacks the cleaning agent to remove residual cleaning agent from the assembly, wherein;
said process for cleaning is performed on a TFF assembly wherein cleaning can be performed in parallel when valves between cassettes are open and in series when valves between cassettes are closed.
2. The process of claim 1 , wherein the assembly is tested to determine whether the surface of the filtration membrane has been restored to a desired level of cleanliness.
3. The process of claim 2 , wherein the level of cleanliness is determined by measuring the normalized water permeability of the at least one TFF cassette and filter membranes.
4. The process of claim 2 , wherein the cleanliness of the TFF assembly is tested after cleaning by flushing the system with a solution that lacks cleaning agent and assaying for residual total organic carbon (TOC).
5. The process of claim 1 , wherein the cleaning agent is NaOH.
6. The process of claim 1 , wherein the TFF assembly is used for up to twenty (20) cycles prior to cleaning.