ABSTRACT
Lysozyme is an antimicrobial enzyme derived from chicken egg white, tear secretions, and some bacteriophages, as well as having recently been produced in transgenic animals through recombinant processes. The hydrolytic enzyme cleaves β(14) glycosidic bonds in microbial peptidoglycan, resulting in cytoplasmic contents leakage and cell death. Hen egg-white lysozyme (HEWL) is considered generally recognized as safe (GRAS) in the United States, and exhibits antimicrobial activity against multiple foodborne Gram-positive bacterial organisms, including Micrococcus, Clostridium, Listeria, Streptococcus, and Staphylococcus spp., amongst others. Additionally, Gram-negative microorganisms can be rendered sensitive to lysozymes by the use of chelators (e.g., phosphates, EDTA) that facilitate microbial inhibition. Lysozyme exhibits enhanced solubility at reduced pH; research has shown that acid-hydrolyzed oligopeptides from lysozyme exhibit antimicrobial activity, and that the enzyme’s catalytic activity may be independent of its antimicrobial activity. The combination of lysozyme with other antimicrobials can produce effective antimicrobial hurdle processes for food preservation, potentially accommodating clean-label food product needs for food manufacturers.
