Selective isolation of cationic amino acids and peptides by electro-membrane filtration

Abstract

In the food industry there is a clear trend towards the production of speciality products with a high added value. Electro-membrane filtration (EMF) can be used to separate and concentrate these products from complex solutions. With EMF, lysine was separated from a model solution and a protein hydrolysate both containing leucine. The lysine fraction in the permeate ranged from 0.86 to 0.96. The lysine transport rate and purity were improved by increasing the potential difference from 20 V to 40 V. Reduction of the transmembrane pressure from 2 to 0.5 bar improved the purity at a practically unchanged lysine transport rate. An enriched fraction of antibacterial cationic peptides (e.g. lactoferricin-B) could be produced from a lactoferrin hydrolysate using EMF. Isolation of these bioactive peptides is normally expensive due to the complex nature of the hydrolysate feed. EMF has the potential to become an attractive (partial) isolation technology.