Polylysine in its alpha-linked form (poly-L-lysine, alpha-PL) is typically produced by chemical polymerization or solid-phase synthesis, while the natural epsilon form is produced by fermentation. Both forms are polycationic polymers that interact electrostatically with negatively charged components of microbial cell walls and membranes, compromising structural integrity and causing cell death. The alpha-linked form also finds use as a biomaterial coating to improve cell adhesion in pharmaceutical and diagnostic applications.
In food science, polylysine preparations are evaluated for preservation of a wide range of food products owing to their GRAS or equivalent status in several Asian markets and their thermal stability. Some commercial preparations labeled 'Polylysine' are composed of or contain ε-polylysine (see separate entry). Dosage levels of 10–200 ppm are typically effective in most food systems.