E1105 – LYSOZYME

CAS Number: 9001-63-2
 Synonyms: Lysozyme, E1105, muramidase, N-acetylmuramide glycanhydrolase, lysozyme from hen egg white (HEWL), L-zyme, Neutrapharm, Lysobac, Lysozyme hydrochloride
Physical Properties: White to off-white crystalline powder or lyophilized (freeze-dried) powder. Soluble in water (typically 1–10% w/v depending on purity and pH); insoluble in organic solvents. Molecular weight approximately 14,300 Daltons (14.3 kDa) for hen egg white lysozyme. Isoelectric point pI ≈ 11.0 (strongly cationic under neutral and acidic conditions). Optimum pH for enzymatic activity: 4.5–6.5. Optimum temperature: 35–45°C (thermolabile; denatures above 70°C). Specific activity: typically 20,000–40,000 units/mg (one unit defined as decrease in absorbance at 450 nm of 0.001 per minute using Micrococcus lysodeikticus substrate). Stable in dry form (years at 4°C); in solution, stable at low pH (3–5) but denatures at neutral/alkaline pH or high temperature.
Applications: Food preservative (E1105) in cheese (especially semihard and hard cheeses such as Gouda, Edam, Emmental, Grana Padano, Parmigiano-Reggiano, and Provolone) to prevent late blowing caused by Clostridium tyrobutyricum and other clostridial spores. Wine and beer (inhibits lactic acid bacteria and some spoilage yeasts, used in sparkling wine production to prevent refermentation, and in beer to control Pediococcus and Lactobacillus). Seafood (fresh and lightly preserved seafood such as shrimp, crab, and surimi to inhibit Listeria monocytogenes and other Gram-positive pathogens). Meat products (fresh and cooked sausages, luncheon meats, and marinated poultry). Pharmaceuticals (treatment of oral mucositis, periodontitis, aphthous ulcers, and as a preservative in ophthalmic solutions). Cosmetics (preservative in eye drops, contact lens cleaning solutions, skin creams, and toothpaste for its antimicrobial and anti-inflammatory properties). Medical (component of wound healing dressings, treatment of chemotherapy-induced oral ulcers, and as a natural antibiotic). Biotechnology (cell lysis buffer for Gram-positive bacteria in DNA/RNA extraction; enzyme standard in analytical assays).
Description:
 Lysozyme (E1105) is a naturally occurring antimicrobial enzyme that hydrolyzes the peptidoglycan layer of bacterial cell walls, causing cell lysis. The most commercially important source is hen egg white (HEWL – hen egg white lysozyme), where it constitutes approximately 3.5 percent of the egg white protein, making it the second most abundant protein after ovalbumin. Lysozyme is also found in human tears, saliva, milk, and mucus, where it functions as a component of the innate immune system, providing protection against bacterial infections. The enzyme was first discovered by Alexander Fleming (the same scientist who later discovered penicillin) in 1921 when he noticed that his own nasal mucus had bactericidal properties due to the presence of lysozyme.
The mechanism of action of lysozyme is well characterized at the molecular level. Lysozyme is a glycoside hydrolase that specifically cleaves the β-(1,4) glycosidic bonds between N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) in the peptidoglycan layer of bacterial cell walls. Peptidoglycan is a rigid, mesh-like polymer that surrounds the bacterial cell membrane and provides structural integrity. When lysozyme hydrolyzes these bonds, the peptidoglycan structure weakens, and the internal osmotic pressure of the bacterial cell (which can be 5 to 20 atmospheres) causes the cell to swell and burst (lyse). The active site of lysozyme contains two key amino acid residues, glutamic acid 35 (Glu35) and aspartic acid 52 (Asp52), which act as a catalytic pair (a general acid-general base mechanism) to cleave the glycosidic bond. Lysozyme is most effective against Gram-positive bacteria, whose cell walls are composed predominantly of peptidoglycan (40–90% of the cell wall mass) and are directly exposed to the external environment. In contrast, Gram-negative bacteria (such as Escherichia coli, Salmonella, and Pseudomonas) have an additional outer membrane composed of lipopolysaccharide (LPS) and phospholipids that shields the peptidoglycan layer from lysozyme. However, lysozyme can be effective against Gram-negative bacteria when combined with outer membrane permeabilizers such as EDTA (ethylenediaminetetraacetic acid) or when the bacteria are subjected to other stressors such as mild heat, high pressure, or low pH.
In the food industry, lysozyme (E1105) is used most extensively as a preservative in cheese production. Semihard and hard cheeses such as Gouda, Edam, Emmental, Grana Padano, and Parmigiano-Reggiano are susceptible to a spoilage defect known as "late blowing," caused by the germination of Clostridium tyrobutyricum and other clostridial spores that survive pasteurization. These spores are present in raw milk, particularly from silage-fed cows, and are highly heat-resistant. During cheese ripening (aging), the clostridial spores germinate and produce butyric acid and carbon dioxide gas, which causes the cheese to develop undesirable large gas holes, off-flavors (rancid buttery or cheesy odor), and in severe cases, the cheese blocks may crack or explode. Lysozyme is added to the cheese milk (typically at 200–500 mg per liter of milk) or to the brine used for surface treatment. The enzyme diffuses into the cheese matrix and lyses clostridial cells, effectively preventing late blowing without affecting the desirable lactic acid bacteria that are essential for cheese flavor development. Lysozyme is particularly valued in organic cheese production because it is considered a natural processing aid (since it is derived from eggs) and can be used in place of chemical preservatives such as sodium nitrate (E251) or potassium nitrate (E252). However, because lysozyme is derived from egg white, it is a potential allergen (egg allergy), and foods containing E1105 must be labeled accordingly in many jurisdictions.
In wine and beer production, lysozyme is used to inhibit lactic acid bacteria (LAB) such as Oenococcus oeni, Lactobacillus brevis, and Pediococcus damnosus, which can cause wine spoilage (e.g., mousy off-flavor, diacetyl production, and ropiness) and refermentation in sweet or sparkling wines. Unlike sulfur dioxide (SO₂), which is a common antimicrobial but can cause allergic reactions and has negative sensory effects at high concentrations, lysozyme is flavor-neutral and does not kill yeasts, making it ideal for preserving wine without interfering with the desired alcoholic fermentation. In sparkling wine production (Champagne method), lysozyme is added before the secondary fermentation to prevent growth of spoilage bacteria while allowing the added yeasts to ferment and produce carbonation.
Beyond food, lysozyme has significant pharmaceutical and medical applications. It is used in oral care products (toothpaste, mouthwash) to reduce plaque formation and gingivitis by inhibiting Streptococcus mutans and other caries-associated bacteria. In the treatment of oral mucositis (painful ulcerations) caused by chemotherapy or radiotherapy, lysozyme-containing mouth rinses accelerate healing and reduce pain due to the enzyme's anti-inflammatory and tissue-repair properties. Lysozyme is also used as a preservative in ophthalmic solutions (eye drops) and contact lens cleaning solutions because it is gentle on ocular tissues while providing antimicrobial protection. In wound healing, lysozyme-impregnated dressings help prevent infection and promote debridement of necrotic tissue. In clinical diagnostic laboratories, lysozyme is a standard reagent for lysing Gram-positive bacteria to release DNA, RNA, or intracellular proteins for analysis (e.g., DNA extraction from Staphylococcus aureus or Bacillus subtilis). Resistance to lysozyme can develop in bacteria through several mechanisms: modification of peptidoglycan structure (e.g., O-acetylation of N-acetylmuramic acid), alteration of cell wall teichoic acids, or expression of lysozyme inhibitors (e.g., Ivy protein in E. coli). However, widespread resistance is not a major concern because lysozyme is typically used in combination with other preservation hurdles such as low pH, salt, or mild heat. The acceptable daily intake for lysozyme was not specified by JECFA because it is a protein that is digested and degraded like any other dietary protein, with no toxicity or accumulation. The main limitation of lysozyme is its high cost compared to chemical preservatives, its thermolability (denatures at pasteurization temperatures above 70°C, so it must be added after heat treatment), and its allergenicity for individuals with egg allergy. Nevertheless, E1105 is considered an exemplar of "clean label" preservation, being a naturally derived enzyme with a clear mechanism of action and excellent safety profile.

SAFETY INFORMATION ABOUT E1105 – LYSOZYME

First aid measures:
Description of first aid measures:
General advice:
Consult a physician. 
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
 
If inhaled:
If breathed in, move person into fresh air. 
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately. 
Wash off with soap and plenty of water.
Consult a physician.
 
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
 
If swallowed:
Do NOT induce vomiting. 
Never give anything by mouth to an unconscious person. 
Rinse mouth with water. 
Consult a physician.
 
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
 
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment. 
 
Avoid breathing vapours, mist or gas. 
Evacuate personnel to safe areas.
 
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste. 
Keep in suitable, closed containers for disposal.
 
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
 
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place. 
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
 
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
 
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles. 
Faceshield (8-inch minimum). 
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
 
Skin protection:
Handle with gloves. 
Gloves must be inspected prior to use. 
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product. 
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. 
Wash and dry hands.
 
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
 
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. 
 
If the respirator is the sole means of protection, use a full-face supplied air respirator. 
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so. 
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions. 
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
 
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company. 
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product