IngredientsNisin is a polycyclic antibacterial peptide produced by the bacterium Lactococcus lactis that is used as a food preservative. It belongs to a specialized class of ribosomally synthesized and post-translationally modified peptides (RiPPs). Nisin is a commercially successful antimicrobial peptide (AMP) widely used as a food preservative; as a ribosomally synthesized and post-translationally modified peptide, nisin belongs to a diverse family of natural variants. More specifically, subtilin and epidermin are related to nisin; all are members of a class of molecules known as lantibiotics.
Lantibiotics are a growing class of antimicrobial peptides which possess antimicrobial activity against mainly Gram-positive bacteria, including highly resistant strains such as methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci. Within the lantibiotic classification, nisin has been proven to be the most extensively studied elongated type-A lantibiotic.
Nisin is a ribosomally synthesized, cationic, amphiphilic, hydrophobic, five-ring polypeptide having 34 amino acids in its active state and a molecular weight of 3354 Da. It has 34 amino acid residues, including the uncommon amino acids lanthionine (Lan), methyllanthionine (MeLan), didehydroalanine (Dha), and didehydroaminobutyric acid (Dhb).
Nisin is comprised of several unique amino acids resulting from post-translational modifications, such as dehydroalanine, dehydrobutyrine, one lanthionine residue (the A ring), and four beta-methyllanthionine residues (the B, C, D, and E rings). The molecule possesses a characteristic bipartite architecture: the N-terminal domain, containing three post-translationally incorporated (β-methyl)lanthionine rings (rings A, B and C), is linked to the C-terminal rings (rings D and E) by a flexible region, or hinge, consisting of three amino acids (Asn20-Met21-Lys22). It also has a low molecular weight of approximately 3.3 kDa.
Nisin is a natural antimicrobial peptide produced by Lactococcus lactis and widely employed as a food preservative. In the food industry, nisin is obtained from the culturing of L. lactis on natural substrates, such as dextrose, and it is not chemically synthesized. A recent study has highlighted that the genetic capacity to produce nisin is more widespread than previously thought, with over 100 species predicted to encode the genes to produce the peptide.
The bacteriocin nisin is naturally produced by Lactococcus lactis as an inactive prepeptide that is modified post-translationally, resulting in five (methyl-)lanthionine rings characteristic for class Ia bacteriocins; export and proteolytic cleavage of the leader peptide results in release of active nisin. Industrial nisin production is currently performed using natural producer strains, resulting in rather low product purity and limiting its application to preservation of dairy food products.
Six natural nisin variants have been identified to date, namely nisin A, nisin Z, nisin Q, nisin F (produced by strains of Lactococcus lactis), and nisin U and nisin U2 (produced by strains of Streptococcus uberis). More recently, natural nisin variants produced by strains of other genera have been reported, such as nisin U, nisin H, nisin O, nisin J, and nisin P, produced by Blautia spp., Staphylococcus spp., and Streptococcus spp.
This cationic peptide occurs in five natural variants; the two most common being nisin A and nisin Z, which differ by one amino acid at residue 27 — histidine and asparagine, respectively. All nisin variants share a basal structure consisting of five mono-sulfide bridges (lanthionine rings) and three dehydrated amino acid residues, which result from post-translational modifications, but have some amino acid substitutions.
Commercially, nisin is available in several grades of purity and formulations. The primary commercial products include a standard preparation containing approximately 2.5% nisin (w/w) balanced with sodium chloride and denatured milk solids, as well as higher-purity preparations such as nisin ZP (>95% purity) used in research and emerging clinical studies. Nisin has been widely used in dairy products, in meat products, in fruit juices, and in canned foods to extend shelf life under high temperatures. Its low solubility in neutral aqueous solutions, its instability at physiological pH, and its rapid breakdown by proteolytic enzymes has limited its use for processed foods including processed cheese, milk and derivatives, and canned vegetables.
It is almost a century since nisin was discovered in fermented milk cultures, coincidentally in the same year that penicillin was first described. The best studied lantibiotic is nisin, which was first discovered in 1928 by Rogers and Whittier and belongs to the class I lantibiotics. The name "nisin" is believed to derive from N-inhibitory substance, reflecting its early identification as a bacterial inhibitory compound from Lactococcus (then classified as Streptococcus) cultures.
Nisin has been used in the food industry since 1953 and obtained the status as generally recognized as safe (GRAS) in 1988 from the Food and Drug Administration (FDA). Over the last 100 years, this small, highly modified pentacyclic peptide has not only found success in the food industry as a preservative but has also served as the paradigm for understanding the genetic organization, expression, and regulation of genes involved in lantibiotic biosynthesis — one of the few cases of extensive post-translation modification in prokaryotes.
Since its discovery, this highly modified peptide has gained approval by regulators in over 80 countries, including the Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA). Unlike many traditional botanical preparations, nisin's use as an intentional food additive is entirely modern, stemming from its recognition as a natural constituent of certain fermented dairy foods rather than from any documented traditional medicinal system. Its use by cultures historically predates the formal use of isolated nisin only in the sense that fermented milk products naturally containing L. lactis bacteria were consumed across many food cultures, with no explicit medicinal attribution to nisin specifically.
Nisin A has been approved for use as a food preservative by the US Food and Drug Administration (FDA) (US Food and Drug Administration, 1988) and the European Food Safety Authority (EFSA; E number E234). Nisin (E 234) is currently an authorised food additive in the European Union (EU) under Annex II of Regulation (EC) 1333/2008 for use in several food categories. The Codex General Standard for Food Additives allows nisin A up to 12 mg/kg in flavored fluid milk drinks and dairy-based desserts, such as pudding, fruit, or flavored yogurt. A 2017 EFSA opinion increased the acceptable daily intake from 0.13 mg per kilogram body weight per day to 1 mg, and recommended manufacturers can use nisin in unripened cheese at a maximum level of 12 mg per kilogram and in heat-treated meat products at a maximum level of 25 mg per kilogram.
The biosynthesis of nisin A requires eleven genes in three transcription units. The nisin precursor peptide is post-translationally modified after synthesis in the ribosome; serine and threonine residues are subjected to enzymatic dehydration that leads to the production of Dha and Dhb; subsequently, thiol groups from adjacent cysteine residues attack Dha and Dhb double bonds, thioether bonds are formed, and lanthionine and beta-methyl lanthionine are formed, respectively.
NisC is a zinc-dependent metalloprotein that reacts dehydrated residues with cysteine, and in this reaction, part of one molecule is connected to another and a closed loop is formed; the biosynthesis of nisin A can be triggered by this peptide by activating the promoters upstream of NisF and NisA via the NisR/NisK two-component regulatory mechanism. These atypical amino acids are introduced by post-translational modification of a ribosomally synthesized precursor peptide.
The five-ring structure of nisin confers its functional specificity. The A, B, and C rings form a "cage" that facilitates binding of the pyrophosphate moiety of lipid II, thus interfering with cell wall synthesis. This binding in turn enhances the ability of the C-terminal segment, containing rings D and E, to form pores in the cell membrane, resulting in the rapid efflux of ions and cytoplasmic solutes, such as amino acids and nucleotides.
The antimicrobial peptide nisin exerts its activity by a unique dual mechanism: it permeates the cell membranes of Gram-positive bacteria by binding to the cell wall precursor Lipid II and inhibits cell wall synthesis. Through interaction with the membrane-bound cell wall precursor lipid II, nisin inhibits peptidoglycan synthesis and forms highly specific pores; the combination of two killing mechanisms in one molecule potentiates antibiotic activity and results in nanomolar MIC values.
The antibiotic peptide nisin is the first known lantibiotic that uses a docking molecule within the bacterial cytoplasmic membrane for pore formation; through specific interaction with the cell wall precursor lipid II, nisin forms defined pores which are stable for seconds and have pore diameters of 2 to 2.5 nm.
Nisin can permeabilize membranes by two different mechanisms: (I) through a low-affinity permeation mechanism that is only observed in model systems; (II) by a much higher nisin–Lipid II–dependent targeted pore-formation mechanism. In the first mode, which requires micromolar concentrations of nisin and presence of anionic lipids in the target membrane, nisin binds to the anionic lipids and is subsequently inserted in the membrane at the position of the phospholipid head groups. Pore formation is believed to cause rapid dissipation of transmembrane electrostatic potential, resulting in membrane permeabilization and rapid bacterial cell death.
At high concentration regimes of nisin, interaction with phospholipids may equally deform the bacterial cell membranes even under significantly varying amounts of lipid-II. An alternative mechanism of bactericidal action of nisin involves the segregation and loss of lipid II. Membrane thinning, destabilization, and decrease in lipid density depend on the degree of oligomerization of nisin.
Nisin is the only officially recognized non-toxic bacteriocin with an inhibitory effect on the growth of a broad range of Gram-positive bacteria and spores. This spore-inhibiting property is particularly important for its application in food systems, especially against Clostridium botulinum. Nisin functions in cheese products as an antimicrobial agent, particularly for the inhibition of the outgrowth of Clostridium botulinum spores and toxin formation.
Nisin is the prototype of the lantibiotic group of antimicrobial peptides; it exhibits broad spectrum inhibition of gram-positive bacteria including important food pathogens and clinically relevant antibiotic-resistant bacteria. By targeting the universal peptidoglycan precursor lipid II, nisin has a broad target spectrum including important human pathogens such as Listeria monocytogenes and methicillin-resistant Staphylococcus aureus strains. Nisin can also cause cell wall lysis in certain bacteria, including Staphylococci.
The use of nisin as a food preservative is the best-established and most thoroughly documented application. For its nanomolar-range antimicrobial activity, its virtual lack of toxicity for humans, and its exceptional resistance to thermal treatments, nisin is widely employed as a natural preservative in the dairy and the canning industries. As the most extensively studied elongated type-A lantibiotic, nisin has been proved to reduce the reliance on sterilization processing while improving the nutrition and flavor of food during production; it has been widely used in dairy products, meat products, fruit juices, and canned foods to extend shelf life under high temperatures.
Lantibiotics possess antimicrobial activity even against highly resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE), and some are already in pre-clinical trials. Nisin possesses unique characteristics such as an uncommon structure, amphiphilic nature, low likelihood of promoting bacterial resistance, and strong bactericidal activity against a wide range of pathogenic microorganisms. Evidence in this area remains largely preclinical — based on in vitro minimum inhibitory concentration (MIC) studies and animal models — with no completed human clinical trials as of the current literature.
Nisin is a lantibiotic widely used for the preservation of food and beverages; recently, investigators have reported that nisin may have clinical applications for treating bacterial infections. The aim of one key study was to investigate the effects of ultra pure food grade Nisin ZP (>95% purity) on taxonomically diverse bacteria common to the human oral cavity and saliva-derived multi-species oral biofilms, and to discern the toxicity of nisin against human cells relevant to the oral cavity.
This work demonstrates that nisin is a promising candidate for development as an oral therapeutic anti-biofilm agent; high purity food grade nisin (>95%) exerted anti-biofilm effects against saliva-derived multi-species biofilms without causing cytotoxic effects to the human oral cells. Further investigation of the clinical role of nisin in modulating the microbiome of the biofilm community and its immunomodulatory role in human oral cells are necessary to determine its potential as a therapeutic or prophylactic agent against oral disease.
One study aimed to test whether a nisin probiotic (using L. lactis) can promote a healthier oral microbiome in pathogen-spiked oral biofilms, and found that L. lactis can prevent oral biofilm formation and disrupt 24-h and 48-h pre-formed biofilms. These studies are in vitro and preclinical; rigorous human randomized controlled trials in oral health have not yet been published.
Antibacterial peptides or bacteriocins such as nisin, and a nisin-producing probiotic Lactococcus lactis, have not been examined extensively in the context of periodontal disease, yet warrant examination because of their biomedical benefits in eradicating biofilms and pathogenic bacteria, modulating immune mechanisms, and their safety profile in humans. One study's goal was to examine the potential for nisin and a nisin-producing probiotic to abrogate periodontal bone loss, the host inflammatory response, and changes in oral microbiome composition in a polymicrobial mouse model of periodontal disease.
Published research demonstrated that nisin effectively abrogates the growth of planktonic pathogenic bacteria and biofilm-encased bacteria associated with caries, periodontal disease, and persistent endodontic infections without inducing cytotoxicity to human oral cells; nisin also resets pathogenic oral biofilms towards control/healthy levels in vitro. These findings are preclinical and based primarily on in vitro assays and mouse models.
Nisin has in vitro efficacy against Gram-positive gut pathogens such as Clostridioides difficile and, in combination with cinnamaldehyde and EDTA, has been shown to control the growth of Gram-negative bacteria. An important mechanistic question concerns whether orally ingested nisin survives gastric transit. Orally ingested nisin survives transit through the porcine gastrointestinal tract intact (as evidenced by activity and molecular weight determination), where it impacts both the composition and functioning of the microbiota.
Specifically, nisin treatment caused a reversible decrease in Gram-positive bacteria, resulting in a reshaping of the Firmicutes and a corresponding relative increase in Gram-negative Proteobacteria; these changes were mirrored by modification in relative abundance of pathways involved in acetate, butyrate (decreased) and propionate (increased) synthesis, which correlated with overall reductions in short-chain fatty acid levels in stool. These reversible changes that occur as a result of nisin ingestion demonstrate the potential of bacteriocins like nisin to shape mammalian microbiomes. This evidence is from a porcine model; no comparable human controlled trials have been published.
One investigation evaluated the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract periodontitis-associated gut dysbiosis and to modulate the glycolipid metabolism and inflammation in the liver. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition commensurate with health, while preventing harmful inflammation in the small intestine and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA-Seq analyses confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding, and their restitution following nisin treatment. This work was conducted in a mouse model; it has not been replicated in humans.
Previously, nisin (2.5%, low content) was shown to have antitumor potential in head and neck squamous cell carcinoma (HNSCC) in vitro and in vivo; subsequent studies explored a naturally occurring variant (nisin ZP; 95%, high content) for its antitumor effects in vitro and in vivo.
HNSCC cells treated with increasing concentrations of nisin ZP exhibited increasing levels of apoptosis and decreasing levels of cell proliferation, clonogenic capacity, and sphere formation. Nisin ZP induced apoptosis through a calpain-dependent pathway in HNSCC cells but not in human oral keratinocytes; nisin ZP also induced apoptosis dose-dependently in human umbilical vein endothelial cells (HUVEC) with concomitant decreases in vascular sprout formation in vitro.
Orally administered nisin Z has significantly reduced tumor proliferation in a preclinical model and is currently in a phase I clinical trial for squamous and head and neck carcinoma. A clinical study of oral nisin administration in patients with oral cavity squamous cell carcinoma (OSCC) who are undergoing complete surgical resection surgery with or without adjuvant radiation/chemoradiation is underway at the University of California, San Francisco (UCSF). The primary objectives of this trial include evaluating the safety of nisin administration, as assessed by the frequency and severity of adverse events (Phase I). Secondary objectives include characterizing nisin-induced changes in oral microbiome population structure and function and nisin sensitivity among key oral bacterial species, as well as characterizing inflammatory and anti-tumor cellular responses to nisin in the oral cancer environment.
It must be emphasized that evidence for nisin as an anticancer agent remains at the preclinical and early Phase I stage. No completed randomized controlled human clinical trials demonstrating efficacy in cancer treatment have been published.
Nisin Z decreases the growth of colorectal cancer cells and moderately increases cell death in vitro; oral administration of nisin Z in an intestinal adenoma mouse model revealed a reduction of tumor burden in the middle region of the small intestine; this decreased tumor burden might in part be attributed to a direct anti-inflammatory effect, as well as an indirect effect on the gut microbiota and their metabolites due to nisin Z's antibacterial activity. A dose-dependent effect on NF-κB activation was also demonstrated, as well as shifts in the gut microbiome and microbial metabolites due to nisin Z's antibacterial properties. This evidence is entirely preclinical and requires human studies.
One study investigated the antiproliferative and mechanistic effects of nisin (N) and Urolithin B (UB), individually and in combination, against the human lymphoma cell line HKB-11; cytotoxic efficacy and underlying molecular pathways were evaluated using the Alamar Blue assay, combination index (CI) analysis, flow cytometry, reactive oxygen species (ROS) quantification, and bottom-up proteomics; N and UB displayed notable antiproliferative effects, with IC50 values of 1467 µM and 87.56 µM, respectively. This work is limited to a single in vitro cell line study.
The efficacy of nisin as a food preservative is supported by decades of regulatory review, documented industrial use, and extensive microbiological data. The Joint FAO/WHO Expert Committee on Food Additives (JECFA), European Food Safety Authority (EFSA), and many other national food safety regulatory bodies have assessed nisin A to be a safe and effective preservative when it is added within regulatory limits to food and beverages. This is the only area in which the evidence base is considered complete for human use.
Natural products that target lipid II, such as the lantibiotic nisin, are strategically important in the development of new antibacterial agents to combat the rise of antimicrobial resistance. However, no completed randomized human trials for nisin as a clinical antibiotic treatment have been published. Evidence is limited to in vitro MIC testing and animal models.
Multiple in vitro studies demonstrate nisin's ability to disrupt multi-species oral biofilms and inhibit oral pathogens without damaging human oral cells. These findings are mechanistically plausible but lack clinical validation from controlled human trials.
Preclinical evidence in HNSCC, colorectal cancer, and lymphoma cell lines is accumulating. Recent in vitro and in vivo evidence has indicated a role for nisin as an anticancer agent. A Phase I clinical trial in oral cavity squamous cell carcinoma is underway at UCSF. No efficacy data from completed human trials are available. All anticancer claims remain investigational.
Porcine studies show that orally ingested nisin can survive gastrointestinal transit and modulate the gut microbiome in a reversible manner. There is currently no published human clinical trial directly evaluating intentional nisin supplementation for gut microbiome modulation.
Nisin doses vary substantially across applications:
The Joint FAO/WHO Expert Committee on Food Additives (JECFA), EFSA, and many other national food safety regulatory bodies have assessed nisin A to be a safe and effective preservative when added within regulatory limits to food and beverages; the US FDA granted nisin A with the status of generally recognized as safe (GRAS) in 1988.
In addition to the studies previously evaluated by EFSA in 2006, the Panel considered data from a new subchronic toxicity study; no adverse effects were observed in a repeated dose oral toxicity study in which rats were administered nisin A for 90 days. A no observed adverse effect level (NOAEL) of 225 mg nisin A/kg bw per day was identified as the highest dose tested in this study.
Nisin's safety is secured in part by its fate in the human digestive system; as a polypeptide, nisin is rapidly broken down by natural digestive enzymes (proteases) in the stomach and intestines into inactive amino acids, similar to any other consumed protein. However, as noted in the gut microbiome section, porcine data indicate that some intact nisin does reach the lower gastrointestinal tract under certain conditions.
Its low solubility in neutral aqueous solutions, its instability at physiological pH, and its rapid breakdown by proteolytic enzymes has limited its use for processed foods. As a hydrophobic peptide, nisin is often affected by various factors in the food industry, such as salts, pH, processing temperatures, and even enzymes or fats.
Nisin's primary activity is directed against Gram-positive bacteria. Its efficacy against Gram-negative bacteria is limited by the outer membrane of those organisms, though combination strategies with agents such as EDTA have been explored. The EFSA Panel did not consider the possibility that using nisin in food induces antimicrobial resistance (AMR), nor a possible "modulating effect" on the gut microbiota, as these were deemed to fall outside the remit of the Panel; however, the Panel nonetheless recommended a separate evaluation of these risks.
Nisin treatment caused a reversible decrease in Gram-positive bacteria, resulting in a reshaping of the Firmicutes and a corresponding relative increase in Gram-negative Proteobacteria. While reversibility was observed in the porcine model, the implications for chronic human dietary exposure remain an open question flagged by EFSA for further evaluation. The EFSA Panel considered that the overall exposure estimate was below the new ADI for nisin A for all population groups and concluded that the proposed extension of use of nisin (E 234) as a food additive in unripened cheese and heat-treated meat products would not be of safety concern.
Nisin serves as a natural preservative with antimicrobial properties in various food products, including dairy and beverages, for extending product shelf life; the efficacy and safety of nisin A as a bacteriocin has been well characterized; however, there is limited evidence regarding the efficacy, stability, and safety of nisin Z as a food preservative, as it has not undergone comprehensive regulatory reviews.
Health conditions that Nisin may help support.
Body systems that Nisin may help support.
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