What Is Poly L Lysine? Uses, Safety, Side Effects

What Is Poly L Lysine? Uses, Safety, Side Effects

What is poly l lysine

Table of Contents

Poly l lysine (also known as PolyLysine or PL) is a synthetic compound that is used across the world for various applications. Some of its uses in products and food include for corrosion prevention, chelate manufacturing, corn degerming, gelatin manufacturing, textile production, leather finishing, etc.

In addition to the attention it has garnered due to the above applications, it has also been studied extensively by numerous scientists over the years because of its significant role in living organisms.

What Is poly l lysine?

Poly-L-lysine (PLL) is a positively charged amino acid that can be used as a coating material in the process of cell culture. It has a wide range of applications in the field of biotechnology and medicine, particularly in tissue engineering and cell culture.

Poly-L-lysine is available in both powder and granule forms. The granule form has better mechanical properties than the powder form but both forms can be used for coating.

The chemical formula for poly-L-lysine is C(-NH2)6NHC(-COOH)4. The chemical structure of poly-L-lysine consists of an amino group (NH2), six lysine residues (COOH) and four carboxylic acid groups (COOH).

What Is poly l lysine used for?

Poly-L-lysine is a synthetic amino acid that is used as a coating for culture dishes, cell and tissue culture media, and other materials. It helps to prevent the adhesion of cells to glass surfaces and to prevent bacteria from growing on the surface of solutions.

Poly-L-Lysine is used to help maintain the health of a variety of organisms, including humans and plants. It is also used in the manufacture of leather and synthetic fabrics.

Poly-L-lysine can be used in cell culture experiments to keep cells from sticking to the surface of a dish or flask. It can also be used as an antifungal agent in nutrient media used for growing fungi. As a cationic polymer, it adsorbs negatively charged proteins such as DNA and RNA. This adsorption prevents bacterial contamination during the storage of solutions containing nucleic acids.

Poly L lysine coating is a procedure that involves the application of a positively charged polymer to negatively charged particles. In the case of research, this is often done to nanometer-sized particles such as viruses, DNA or other proteins.

The benefit of this process is that it allows for the separation of coated molecules from other particles in solution. This is particularly useful when you want to separate and purify your sample prior to further study or analysis.

The process of coating with poly L lysine involves three steps:

Step 1: Adsorption – The negative surface of your particle must first be activated so that it can bind with the positively charged polymer. This is done by adding some type of activating agent like EDC (Ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride).

Step 2: Coating – Next you add the poly L lysine which acts as a bridge between your activated surface and your coating solution. This will produce a reaction between both materials that results in an electrostatic bond between them.

Step 3: Immobilization – Finally, you wash off any unreacted materials and allow your particles to dry. This will leave them coated with poly L lysine and ready to use in whatever project you have in mind!

What is poly l lysine made of?

Poly l lysine is a synthetic polymer made up of l-lysine monomers.

It has been used in the food industry as an antioxidant, emulsifier and thickener. In cosmetics, it’s used as a moisturizer and hair conditioner.

Poly l lysine is made by linking together l-lysine molecules with amide bonds. The resulting polymer is water soluble, which means it dissolves in water but not in oil.

The material is also known by its chemical name N-L-Lysine Polymer or PLP for short.

How is poly l lysine made?

One form of poly-L-lysine is pure, while another is mixed with maltodextrin powder in a 50:50 or 25% water solution, which is the most common form. Those two processes are as follows:

  1. ε-poly-L-lysine: made by Streptomyces. Using glucose as the substrate, albulus is fermented aerobically, and ion-exchange resins are used after spray drying.
  2. ε-poly-L-lysine hydrochloride: obtained by fermenting Streptomyces diastatochromogenes and purifying by ion exchange and spray drying.

How does poly l lysine Work?

This is the main preservation mechanism of polylysine:

  • ε-Polylysine is the name given to a highly polymerized polyvalent cation (positively charged) which attaches and interacts with negatively charged microorganism membranes of their living cells and creates holes in the membrane as a result.
  • As a result of its destruction of the cell membrane structure, it leads to the leakage of intracellular substances from microorganisms.
  • It enters the cell through a hole in the membrane, which affects its structure and function. It interferes with the normal physiological metabolism of microorganisms by altering the structure and function of the membrane. By causing the cell to undergo autolysis, and eventually killing the bacterial cell, the infection destroys the transmission of materials and energy within the cell.

These microorganisms (incomplete) are resistant to its antibacterial effects:

  • coli
  • Staphylococcus aureus
  • Subtilis Bacillus
  • Thermophilus streptococcus
  • Bulgaric Lactobacillus
  • Plantarum lactobacillus
  • Cerevisiae Saccharomyces
  • The Pichia
  • Candida
  • Rhizopus niger
  • Tall Mucor


Other names

Poly l-lysine hydrochloride (USP)

Poly l-Lysine HCl

Poly L-Lysine HCL

CAS Number


Chemical Formula

[C6H12N2O] n٠H2O n=25-35

Molecular Weight


Poly l lysine structure



In addition to its strong bactericidal properties, polylysine also has a broad spectrum of antibacterial activity, is water soluble, thermally stable, and will not affect the flavor of food.


There is a slightly bitter taste to the pure product. It is a light yellow powder.

Powdered hydrochloride salt: white to cream-yellow in color.


Insoluble in ethanol, ethyl acetate, and ether, but soluble in water.


The product works well with PH values ranging from 3 to 9 and can be used on a wide variety of food products.


When treated for 20 min in an aqueous solution at 120 °C, polylysine doesn’t decompose or lose its antibacterial activity. It is therefore possible to apply hot water with raw materials in the context of food processing to enable polylysine to go through the general heat process and prevent secondary contamination of food.

What is the application of ε-poly-l-lysine?

It was first applied commercially in Japan, then in Korea and the United States.In 2014, China approved ε-PL and its hydrochloride as a new food preservative for use in foods and drinks. The preservative could be sold mainly in the food and beverage industry.


It may be found in the following foods:

  • Rice
  • Pickles
  • Soft drinks
  • Yogurt
  • Soups
  • Salad dressings
  • Fruit-flavored drinks
  • Fish and shellfish-based foods
  • Tomato-based sauces
  • Processed cheese and cheese spreads

Use as Additives or Preservatives

As an antimicrobial food additive, poly-L-lysine can not only be used alone, but also mixed with other ingredients. In addition to synergizing with hydrochloric acid, acetic acid, citric acid, malic acid, and glycine, it also inhibits the formation of triglycerides.

There is significant synergistic effect between it and another natural preservative, Nisin, when used together to prevent Listeria monocytogenes and Bacillus cereus. ε-PL inhibits yeast and Escherichia coli in a way Nisin cannot.

It exhibits an antibacterial effect against Bacillus subtilis and Aspergillus flavus in synergistic relationship with glycine. Bacillus subtilis growth can be effectively inhibited through the combined use of “PL” and “acetic acid.”

Coating in Cell Culture

Coverslips coated with poly-L-lysine are commonly used in medical experiments to promote cell adhesion to solid surfaces (glassware and plasticware). Since poly-L-lysine hydrobromide solution (0.01%) interacts with anions on tissue slides and produces strong adhesion, it is widely used as an adhesive for tissue slides.

In this field, alpha-Poly-L-lysine (not food grade) is used instead of ε-Poly-L-lysine.

Is poly l lysine safe to use?

Yes, After ingestion, it partially hydrolyzes to L-lysine (an essential amino acid) which is considered safer than chemical preservatives. In addition to its preservation function, it also serves as a nutritional supplement.

The National Health Commission of the People’s Republic of China (NHC) approved it in 2014 after approval by the Japan Ministry of Health, Labour and Welfare, the U.S. FDA in 2003. Other countries have also approved it.

In today’s food industry, synthetic chemicals like sodium benzoate and potassium sorbate are commonly used as preservatives. As a result, consumers are most concerned about the safety of their food and seek safe preservatives, which is why biological preservatives are the most popular.


The Food and Drug Administration (FDA) made no objections in 2004 to the conclusion of the Japanese rice manufacturer Chisso Corporation that polylysine may be used as an antimicrobial agent in cooked rice and sushi rice at 50 mg/kg maximum use levels.

China NHC

A variety of products can be made using polylysine, and cooked meat products, including baked goods, fruit and vegetable juices, and their beverages. Here is a list of foods that can be used with polylysine hydrochloride:

  • Nuts, seeds, grains, fruits, vegetables, roots, edible fungi, and algae
  • Products made from rice
  • Products made from wheat flour
  • Products made from cereals
  • Products derived from meat
  • The condiment
  • Drinking
  • Corned beef and eggs with spices

What are the side effects of poly-l-lysine?

Poly-L-Lysine is a very safe drug. It is not harmful if taken as per the prescribed dosage.

Some of the side effects of Poly-L-Lysine include:

Itching, redness, burning, or swelling at the application site



The main difference between L-lysine and Poly-L-lysine is their molecular structure and the number of repeating units.

L-lysine is an essential amino acid found in almost all protein-rich foods, such as milk, meat, eggs, fish, beans, and grains. It is also produced naturally by the body from other amino acids. L-lysine is used for treating herpes virus infections in children to prevent recurrences. It can be given to newborns if they are at risk for herpes infection during birth (HSV).

Poly-L-lysine is a synthetic polymer that has a positive charge. It can be used to coat surfaces with antimicrobial properties or to increase the solution’s viscosity.

How to make poly-lysine solution?

The poly-lysine solution is a mixture of lysine and water, which is used in biochemistry experiments. It acts as a protein coating agent in some experiments. The concentration of the poly-lysine solution is calculated by the total number of moles of lysine divided by the total volume of solution.

The following procedure describes how to make a poly-lysine solution:

1. Prepare a 1 M stock solution of lysine hydrochloride (MW 100,000 g/mol) by dissolving 3.0 g in 100 mL of water at room temperature.

2. Dilute the stock solution so that each 0.5 mL contains 1 mM lysine hydrochloride and count the number of moles of lysines per liter (i.e., 1 M).

3. Calculate the volume needed to achieve this concentration using the following equation: V = nM / C, where C = concentration (mM), n = number of moles per liter (1), and V = volume (ml).

What is poly l lysine coating principle?

Poly L-Lysine Coating is the most common coating method used in the industry. This coating method is based on the principle that lysine has both positive and negative charges, which can be used to attract and bind to negatively charged surfaces.

In this process, an electrostatic charge is applied to the surface of the product through a corona discharge or corona treatment. Then, a solution containing positively charged poly L-lysine molecules is sprayed onto the surface of the product. As an electrostatic charge attracts negatively charged particles, so will the positively charged poly L-lysine molecules attract negatively charged particles on the surface of your product.

The result is a layer of positively charged poly L-lysine molecules over your product’s surface to protect it from contamination by foreign matter such as dust, grease, fingerprints, and other contaminants that may cause damage during storage or handling.

Poly-l-lysine vs Poly-d-lysine

Poly-l-lysine and poly-d-lysine are two different types of lysine. Both are used as additives in animal feed and in the manufacturing process of foods. The difference between them is that they have different amino acids in their chains.

Poly-d-lysine is an amino acid with a molecular weight of 575 grams per mole, while poly-l-lysine has a molecular weight of 645 grams per mole. Poly-d-lysine is also known as pDLys and Poly DLys.

The chemical structure of both molecules includes a positively charged nitrogen atom that bonds with negatively charged phosphate groups found in DNA, RNA and proteins. This allows both molecules to bind to these substances without disrupting their function.

What is the common form of poly-l-lysine?

Poly-L-lysine is a synthetic amino acid, and therefore not a natural product. It is available in various grades, with different molecular weights.

The two most common forms are:

Poly-L-lysine (MW 30000) – this is the form used in laboratories. It has a high molecular weight so it precipitates easily when added to solutions and as such is not ideal for use in culturing cells (cells will not take up these particles). However, it can be used in vitro to coat culture dishes or flasks to prevent the attachment of bacteria and fungi.

Poly-L-lysine hydrochloride (MW 3000) – this form has a lower molecular weight than MW 30000 and therefore is more soluble at neutral pH but still precipitates at acidic pH (7.0). This makes it ideal for coating culture dishes because it does not interfere with cell growth but does prevent bacterial and fungal adhesion.

Where to buy poly-l-lysine?

You can buy poly-l-lysine from Amazon, eBay, and other online retailers.

The most important thing to look for when buying poly-l-lysine is that it is pure and made in the United States.

There are many different brands of poly-l-lysine on the market, but many of them are made in China or India.  for Grade Chemical is one reliable poly l lysine supplier in China. you can purchase bulk quantity poly l lysine from them.

Frequently asked questions

Is poly-l-lysine natural?

Poly-l-lysine is a synthetic amino acid, and it is not naturally occurring in nature. Poly-l-lysine is used in a wide variety of medical applications, including as an anti-inflammatory agent and a treatment for burns.

Is poly-l-lysine gluten free?

Although poly-l-lysine is derived from wheat, it is not considered a gluten allergen because it does not contain any protein molecules. Therefore, poly-l-lysine is not considered a gluten allergen.

Is poly-l-lysine vegan?

Poly-L-lysine is not vegan. Poly-L-lysine is made from the fermentation of bacteria and yeast, which are both animals.

Is Poly-L-lysine toxic to cells?

Poly-L-lysine is not toxic to cells. Poly-L-lysine is a synthetic amino acid that is used as a cell culture medium, as well as in lab experiments involving cells. It has been deemed non-toxic by the FDA and is considered safe for use in both humans and animals.

Is polylysine a preservative?

Polylysine is not a preservative. Preservatives are substances that are added to food to prevent food spoilage, but polylysine is an additive that helps to preserve the color and texture of food.


If you follow its label diligently, this supplement is safe for use. Consult a doctor before starting any new supplements or medications, and make sure you are aware of any potential interactions with other substances or any pre-existing conditions. Common side effects when taking Poly L Lysine include an upset stomach and diarrhea, so it’s important to take this supplement with food and plenty of water.

Sophie Feng

Sophie Feng

Sophie Feng is the author of gradechemical.com, she is the co-founder of the grade chemical network. She has been in grade chemical company since 2017, with a working knowledge of food chemical .

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