Membrane filtration is an efficient method for bioseparations for its multiple benefits, such as product sterilization, solute removal, product concentration, purification, and solute fractionation.
Membranes, being semi-permeable, catch or restrict heavier molecules while allowing the smaller ones to pass through. They are of different sizes and are used appropriately in the pharmaceutical and biotech sectors. In this article, we shall speak in detail about the major applications in these industries.
Broad classification of membranes
Membranes are usually classified based on their pore size and membrane structure.
When pore size is considered, membranes are divided as follows:
- Microfiltration membranes for fine particles mainly for solid/colloid – liquid separations
- Ultrafiltration membranes for macromolecular separation and fractionation
- Nanofiltration membranes for the separation, concentration and purification of peptides, sugars, and hormones and salts
- Reverse osmosis for water purification and desalination
The structure of the membranes can be any of the following:
- Homogenous
- Asymmetrical with 2 layers
- Composite
Membrane filtration for clarification of fermentation broths and recovering products
Fermentation broths consist of products of interest along with multiple organic and inorganic substances. Recovering the products that could be API, Small molecule, Enzyme, Peptides, Antibiotics, etc. from fermentation broth is a complex multi-step process that includes membrane filters of different types (MF/UF/NF/RO) based on product type and separation goal.
- The process starts with microporous MF membrane filters used to separate microorganisms and cells, colloids, etc. While the soluble cell free product comes into the permeate stream for further downstream. Diafiltration process is also part of MF process that helps to recover the complete product.
- Once we have cell free product stream then based on the type and nature of product UF / NF process is used to concentrate or purify the product.
- At times at final stage RO process is also integrated to recover water for recycle
Various membrane filtration steps are carried out through the process at pre-defined temperatures and atmospheric conditions.
Recovering solvents from a dilute product
Solvent recovery is yet another wonderful application for membrane filters. Solvent stable Nanofiltration / Reverse osmosis membrane systems are used for concentrating product from process stream, resulting in enriching product / API in reject stream & recovering solvent in permeate stream that can be recycled back. NF process needs much lower energy compared to distillation process and thus helps in improving process economics. NF works at room temperature suitable for heat labile products to reduce degradation of product during the distillation.
Conclusion
Membrane filtration is a crucial process in the pharmaceutical and biotechnology industry as it simplifies multiple steps in the filtration, recovery, and production procedures.
At Permionics, we have an integrated membrane and system manufacturing facility to tailor-make membranes as per need. We invite you to take a look at the various technologically-advanced membranes, made completely in India. We are the first and only company so far to have accomplished this milestone.
