Egg-derived lysozyme (Gallus gallus domesticus; E1105)
Bacteriolytic enzyme (N-acetylmuramidase) isolated from egg white (albumen) and used as a technological aid/preservative in foods and beverages (e.g., hard/semi-hard cheeses against late blowing by Clostridium; wines to modulate lactic bacteria). Supplied as powder (crystalline or spray-dried) or solution. It is a basic protein (~14.3 kDa; pI ~11) with four disulfide bonds, active mainly against Gram-positive bacteria.
Caloric value (per 100 g of product)
~360–400 kcal/100 g (pure protein ≈ 4 kcal/g).
At use levels (mg/kg or mg/L) the energy contribution is negligible.
Key constituents
Enzyme protein: lysozyme (sometimes as hydrochloride salt).
Traces: residual egg-white proteins, salts (Cl⁻), moisture.
Analytical markers: enzymatic activity (U/mg with Micrococcus lysodeikticus assay), protein purity (%), moisture, ash, chlorides.
Mechanism of action and spectrum
Hydrolyses the β(1→4) linkage between N-acetylmuramic acid and N-acetylglucosamine in peptidoglycan, weakening the cell wall of Gram-positive bacteria (e.g., Lactobacillus, Pediococcus, Clostridium). Activity is limited on Gram-negatives (outer membrane barrier) but can increase in the presence of suitable chelators/permeabilizers. Ineffective on yeasts and molds.
Lipid profile (per 100 g; always reported)
Total fat <0.5 g/100 g (trace).
SFA/MUFA/PUFA (n-6/n-3): not nutritionally significant.
Trans/CLA: absent. Cholesterol: absent.
Production process
Pasteurized egg white → selective capture (e.g., cation-exchange resins) → elution and concentration (UF/DF) → optional conversion to hydrochloride → crystallization or spray-drying → sieving and standardization (activity/purity) → barrier packaging. Controls for egg allergens, microbiology, metals, and process residues.
Sensory and technological properties
Appearance/solubility: white to off-white powder, highly water-soluble.
Stability: good in dry form; in solution most stable around pH 4–7; typical activity optimum pH 4.5–6.5 (matrix-dependent). Thermosensitive above 70–80 °C (denaturation), partially stabilized by sugars/salts.
Interactions: binds polyanions (e.g., pectins, carrageenans) to form complexes; in wine may cause protein haze (manage with bentonite/fining).
Food applications
Cheese (hard/semi-hard): prevention of late blowing (Clostridium tyrobutyricum); added to milk/curd.
Wine: control of lactic bacteria (selective MLF management or stabilization).
Other matrices: beers/ferments, acid preserves, RTE cooked meats (surface).
Indicative dosages (always per local regulations and pilot trials): 10–400 mg/kg (solids) or 50–500 mg/L (beverages), depending on microbial load, pH, and aw.
Nutrition and health
An egg protein with enzymatic function; no health claims should be made without authorization. At realistic doses the nutritional contribution is immaterial.
Quality and specifications (typical topics)
Activity: U/mg (substrate M. lysodeikticus, A₄₅₀ decrease).
Purity: ≥90–99% protein; moisture; ash/chlorides (if HCl-lysozyme).
Solution pH (1% w/v), bulk density, granulometry.
Microbiology: low TVC, pathogen-free; endotoxins (for pharma grades).
Allergen: egg presence must be managed and declared; verify cross-contact.
Storage and shelf life
Store cool, dry, and dark (typically <25 °C) in airtight, low-permeability containers; protect from humidity. In solution: use promptly, keep at ~4 °C; avoid repeated freeze–thaw. Apply FIFO.
Allergens and safety
Derived from egg → major allergen: mandatory labeling where required (including in wines and cheeses). Not suitable for egg-allergic individuals. Respect authorized uses/limits (additive E1105 where permitted). Consider risks of haze and interactions with stabilizers/fines.
INCI functions in cosmetics
Entry: Lysozyme. Roles: antimicrobial, skin conditioning, deodorant/oral care; potential sensitization in egg-allergic users—include appropriate preservation and labeling.
Troubleshooting
Loss of efficacy → pH/temperature off-optimum or high Gram-negative load → adjust pH, combine with suitable chelators, review dose/contact time.
Wine haze → protein precipitation → bentonite fining and cold filtration.
Residual activity in cheese → overdosage → titrate to spore load and process.
Undeclared allergen → recall risk → strengthen label review and traceability.
Sustainability and supply chain
Adds value to the egg-processing by-product stream; impacts from resins/solutions and effluents (treat to BOD/COD targets). Use recyclable barrier packaging; control T/RH in logistics.
Conclusion
Egg-derived lysozyme is a targeted tool for bacterial control in sensitive food matrices, with strong efficacy against Gram-positives and established use in cheese and wine. Performance hinges on pH, dose, contact time, and matrix interactions; allergen management and colloidal stability (wine) are key quality points.
Mini-glossary
E1105 — egg lysozyme (EU additive code)
U/mg — activity units per mg protein (Micrococcus assay)
pI — isoelectric point
MLF/MALO — malolactic fermentation
aw — water activity
TVC — total viable count
FIFO — first in, first out
BOD/COD — biochemical/chemical oxygen demand (effluents)
SFA/MUFA/PUFA (n-6/n-3) — fatty-acid profile (here negligible in absolute terms)
Lysozyme has several applications in the medical field. It is used as a natural antimicrobial agent, as it can break down the cell walls of gram-positive bacteria. It is also used as a preservative in some pharmaceutical and food products. Additionally, lysozyme is being studied for its immunomodulatory and anti-inflammatory properties and may have potential use in the therapy of inflammatory diseases and as a biomarker for certain pathological conditions.
It acts as an antioxidant, anti-inflammatory and antibacterial agent especially against Gram-positive and Gram-negative bacteria (1), acts as a protective agent in Alzheimer's disease (2), in the treatment of infections by Staffilococcus Aureus bacteria (3) and is an effective substitute for chlorhexidine and benzidine in the treatment of acute pharyngitis (4).
Cosmetics
Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.
- Molecular Formula C99H159N37O23
- Molecular Weight 2235.6
- CAS 9001-63-2 235-747-3
- UNII
- EC number 232-620-4
References_________________________________________________________________________
(1) Vilcacundo R, Méndez P, Reyes W, Romero H, Pinto A, Carrillo W. Antibacterial Activity of Hen Egg White Lysozyme Denatured by Thermal and Chemical Treatments. Sci Pharm. 2018 Oct 30;86(4):E48. doi: 10.3390/scipharm86040048.
Abstract. The aim of this study was to increase the antibacterial spectrum of modified hen egg white lysozyme (HEWL) with thermal and chemical treatments against Gram-negative bacteria. The antibacterial activity of heat-denatured HEWL and chemical denatured HEWL against Gram-negative and Gram-positive bacteria was evaluated in 15 h of incubation tests. HEWL was denatured by heating at pH 6.0 and pH 7.0 and chemical denaturing was carried out for 1.0, 1.5, 2.0, and 4.0 h with DL-Dithiothreitol (DTT). HEWL modified by thermal and chemical treatments was characterized using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis method. Heat-denatured HEWL lytic activity against Micrococcus lysodeikticus lessened with increasing temperature and time of incubation with the chemical agent (DTT). The loss of lytic activity in modified HEWL suggests that the mechanism of action of the antibacterial activity is not dependent on the lytic activity. Thermal and chemical treatments of HEWL enabled the production of oligoforms and increased antibacterial activity over a wider spectrum. Heat-denatured HEWL at pH 6.0 and chemically-denatured HEWL increased the HEWL antibacterial spectrum against Gram-negative bacteria (Escherichia coli ATCC 25922). HEWL at 120 °C and pH 6.0 (1.0 mg/mL) inhibited 78.20% of the growth of E. coli. HEWL/DTT treatment for 4.0 h (1.0 mg/mL) inhibited 68.75% of the growth E. coli. Heat-denatured HEWL at pH 6.0 and pH 7.0 and chemically-denatured HEWL (1.0, 1.5, 2.0, and 4.0 h with DTT) were active against Gram-positive bacteria (Staphylococcus carnosus CECT 4491T). Heat-denatured and chemical-denatured HEWL caused the death of the bacteria with the destruction of the cell wall. LIVE/DEAD assays of fluorescent dye stain of the membrane cell showed membrane perturbation of bacteria after incubation with modified HEWL. The cell wall destruction was viewed using electron microscopy. The results obtained in this study suggest that heat-denatured HEWL at pH 6.0 and chemical-denatured HEWL treatments increase the HEWL antibacterial activity against Gram-negative bacteria.
(2) Helmfors L, Boman A, Civitelli L, Nath S, Sandin L, Janefjord C, McCann H, Zetterberg H, Blennow K, Halliday G, Brorsson AC, Kågedal K. Protective properties of lysozyme on β-amyloid pathology: implications for Alzheimer disease. Neurobiol Dis. 2015 Nov;83:122-33. doi: 10.1016/j.nbd.2015.08.024.
(3) Chen, L.L., Shi, W.P., Zhang, T.D., Zhou, Y.Q., Zhao, F.Z., Ge, W.Y., Jin, X.Q., Lin, W.J., Guo, W.H. and Yin, D.C., 2022. Antibacterial activity of lysozyme-loaded cream against MRSA and promotion of scalded wound healing. International Journal of Pharmaceutics, 627, p.122200.
Abstract. Staphylococcus aureus (S. aureus) infection, especially its drug-resistant bacterial infection, is a great challenge often faced by clinicians and patients, and it is also one of the most important threats to public health. Finding a safe and effective antibacterial agent is of great significance for the prevention and treatment of S. aureus infection. Lysozyme is known to have antibacterial effects against Gram-positive bacteria including S. aureus. Here, high-quality lysozyme with a purity of more than 99% and an activity of more than 60, 000 U/mg was prepared from egg white, which showed excellent antibacterial activity against three strains of S. aureus, especially against MRSA. Furthermore, an antibacterial cream loaded with lysozyme was prepared and tested in scald wound healing. The lysozyme-loaded cream exhibited the effect of preventing wound infection and promoting wound healing on scalds, and no toxicity was found in animal organs. Overall, lysozyme showed great application potential in the prevention and treatment of infections caused by S. aureus and scalded wound healing. The most remarkable discovery in this work is the unexpectedly powerful inhibitory effect of lysozyme on the drug-resistant bacterial, especially MRSA, which is usually very difficult to deal with using normal antibacterial drugs.
(4) Golac-Guzina, N., Novaković, Z., Sarajlić, Z., Šukalo, A., Džananović, J., Glamočlija, U., Kapo, B., Čordalija, V. and Mehić, M., 2019. Comparative study of the efficacy of the lysozyme, benzydamine and chlorhexidine oral spray in the treatment of acute tonsillopharyngitis-results of a pilot study. Acta Medica Academica, 48(2), pp.140-146.
Abstract. Objective. Lysozyme is a natural antimicrobial and immunomodullatory enzyme, which is produced as a host response to infectious agents. The objective of this study was to compare the efficacy and safety of lysozyme-based versus benzydamine and chlorhexidine-based oral spray in patients with an acute tonsillopharyngitis associaated with a common cold. Patients and Methods. A prospective two-arm pilot study (lysozyme/cetylpyridinium/lidocaine spray versus: benzydamine spray—arm 1; chlorhexidine/lidocaine spray—arm 2) was conducted in the primary health care unit. Efficacy was evaluated by the patient’s self-assessment of pain, difficulty in swallowing and the throat swelling, by using the visual analog scale (VAS) at baseline and three follow-up visits. Safety was evaluated by the assessment of the frequency and severity of adverse effects. Results. Lysozyme-based spray reduced pain faster than benzydamine-based spray and slower than chlorhexidine-based spray. Lysozyme-based and chlorhexidine-based sprays similarly reduced difficulty in swallowing, but were faster than benzydamine-based spray. Similar effects on the reduction of throat swelling were seen in all treated groups. All tested products showed proper safety and were well tolerated, with no serious adverse events reported. Conclusions. The lysozyme-based oral spray was shown to be effective and safe in the reduction of pain, difficulty in swallowing and throat swelling in patients with acute tonsillopharyngitis associated with a common cold. Lysozyme-based oral spray (containing natural compound with advantages of influencing immune system and preventing recurrences) had similar activity to benzydamine and chlorhexidine-based oral antiseptic sprays.
Lysozyme (egg) 
