Use of Bacteriocins and Bacteriocinogenic Beneficial Organisms in Food Products: Benefits, Challenges, Concerns

Purification and characterization of a bacteriocin produced by the probiotic Lactiplantibacillus plantarum subsp. argentoratensis strain I1B

This study is aimed to characterize a broad-spectrum bacteriocin produced by Lactiplantibacillus plantarum subsp. argentoratensis strain I1B of fermented food origin and also to evaluate the in vitro probiotic properties of this strain. Cell supernatant of this strain showed broad-spectrum antibacterial activity against five prominent foodborne pathogens viz. Salmonella typhi 950, Escherichia coli 728, Yersinia enterocolitica 861, Listeria monocytogenes 657, and Klebsiella pneumoniae 618 with the strongest activity against the S. typhi 950. Cell supernatant also exhibited stability to proteolytic enzyme treatment, pH, and temperature. Optimum bacteriocin production was at 20-24 h of incubation in MRS broth at 37 °C with pH 6.0. The bacteriocin activity was retained in the 70% ammonium sulfate precipitate fraction, which was further purified using gel filtration chromatography (Sephadex G25 column) to the level of a single band on the SDS-PAGE and the activity was confirmed by zymogram. The molecular mass of the bacteriocin was found to be 22,199 Daltons. The pure molecule was identified using LC-MS/MS and was found to be an Adherence Protein with a sequence of chitin-binding domain consisting of 201 amino acid residues. The isolated strain exhibited potential probiotic activity within the established regulations and did not raise any possible safety concerns. This work reports a potent bacteriocin produced by a listed probiotic organism with latent postbiotic activity which could be used as a potential biopreservatives.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04279-5.

Postbiotic Potential of Newly Isolated Riboflavin-Overproducing Lactiplantibacillus plantarum Strains

Lactic acid bacteria (LAB) are food-grade microorganisms able to produce and release bioactive compounds of interest to human health. Some LAB strains can synthesize vitamin B2, i.e., riboflavin, a micronutrient essential for cellular metabolism. In this work, six Lactiplantibacillus plantarum isolated from fruits of the Mediterranean area were exposed to the selective pressure of roseoflavin in order to select spontaneous riboflavin-overproducing phenotypes. The best strains, as determined by the level of riboflavin produced, were characterized for some basic probiotic features, including antibacterial activity, production of organic acids, antibiotic resistance, and survival under digestive stresses using an in vitro gut model. The strain L. plantarum Lp 187_B2, which produced the highest riboflavin level (6 mg/L), exhibited good resistance to gastro-intestinal stress and a relevant capacity to antagonize undesired bacteria, was selected for additional investigations to assess its capacity to protect intestinal homeostasis. When used as a postbiotic, Lp 187_B2 significantly increased trans-epithelial electrical resistance (TEER) in Caco-2 cell monolayers, an in vitro model of the intestinal barrier. Moreover, in a Caco-2/THP-1 co-culture system, mimicking the inflamed bowel, Lp 187_B2 postbiotics significantly inhibited the release of TNF-α by macrophages, thus pointing to gut-barrier strengthening and potential anti-inflammatory properties. Though a validation in vivo is required, our preliminary results indicate that L. plantarum Lp 187_B2 could be successfully applied as both probiotic and postbiotic formulations for improving human health.

Harnessing the Power of Bacteriocins: A Comprehensive Review on Sources, Mechanisms, and Applications in Food Preservation and Safety

The Sustainable Development Goals (SDGs) emphasize the importance of food safety, prolonged shelf life, and reduced food waste, all of which rely on effective food preservation methods. Bacteriocins, natural antimicrobial substances produced by lactic acid bacteria (LAB), have potential applications in food preservation. This review highlights the role of LAB-derived bacteriocins in preserving food. Bacteriocins are highly effective against foodborne infections because they target cell membranes, break down enzymes, and interfere with cellular activities. The following study used molecular docking to understand the interaction of bacteriocins and their mode of action. With their natural origin and specific action, bacteriocins offer a promising strategy for preventing foodborne diseases and extending shelf life without impacting sensory characteristics. However, challenges such as stable manufacturing, regulatory hurdles, and cost effectiveness hinder the wide adoption of bacteriocins. Nevertheless, LAB-derived bacteriocins offer a safe and efficient approach to improving food preservation, enhancing food safety, and reducing reliance on artificial preservatives. Moreover, immobilized bacteriocins have the potential to be integrated into antimicrobial packaging films, providing a targeted way to reduce the risk of foodborne pathogen contamination and improve food safety. Exploring novel bacteriocins presents exciting opportunities for advancing food preservation and safety. The present study also highlights recent advancements in food preservation through bacteriocins.

Harnessing bacterial antimicrobial peptides: a comprehensive review on properties, mechanisms, applications, and challenges in combating antimicrobial resistance

Antimicrobial resistance (AMR) is a significant global health concern due to the persistence of pathogens and the emergence of resistance in bacterial infections. Bacterial-derived antimicrobial peptides (BAMPs) have emerged as a promising strategy to combat these challenges. Known for their diversity and multifaceted nature, BAMPs are notable bioactive agents that exhibit potent antimicrobial activities against various pathogens. This review explores the intricate properties and underlying mechanisms of BAMPs, emphasizing their diverse applications in addressing AMR. Additionally, the review investigates the mechanisms, analyses the challenges in utilizing BAMPs effectively, and examines their potential applications and associated deployment challenges providing comprehensive insights into how BAMPs can be harnessed to combat AMR across different domains. The significance of this review lies in highlighting the potential of BAMPs as transformative agents in combating AMR, offering sustainable and eco-friendly solutions to this pressing global health challenge.

Effect of Lactococcus lactis JNU 534 Supplementation on the Performance, Blood Parameters and Meat Characteristics of Salmonella enteritidis Inoculated Broilers

Salmonellosis in broilers is a disease with considerable economic implications for the poultry industry. As a foodborne illness, it also poses a public health risk due to potential cross-contamination. Probiotics have been proposed as alternative feed additives aiming to enhance growth, livestock productivity, and overall health. This study investigated the dietary impact of Lactococcus lactis JNU 534 on growth performance, blood characteristics, internal organ weight, and meat quality in broilers inoculated with Salmonella enteritidis (SE). A total of 96 one-day-old Arbor Acres broiler chickens, comprising both sexes, were challenged with SE and randomly assigned into two treatment groups and housed in eight pens (four pens per each treatment, with 12 birds per pen). They were fed a commercial broiler diet for 35 days. The two dietary treatment groups consisted of a control group receiving commercial feed, and a treatment group receiving commercial feed supplemented with 0.3% L. lactis JNU 534. Probiotic supplementation significantly improved average body weight gain, feed efficiency, and carcass yield compared to the control group (p < 0.05). Notably, the abdominal fat pad was significantly reduced in the probiotics group (p < 0.05). Meat quality assessments revealed no significant differences between the groups in terms of meat pH, cooking loss, drip loss, and water-holding capacity. These findings suggest that L. lactis JNU 534 is a promising candidate to mitigate the negative effects of Salmonella on growth performance in commercial broiler farms, without adversely affecting health. Extending the research to other types of livestock could help confirm its wider use as an alternative to antibiotics.

Phenolic Compounds and Bacteriocins: Mechanisms, Interactions, and Applications in Food Preservation and Safety

Beneficial properties of different natural antimicrobials are topics of scientific curiosity for improving safety and extending the shelf life of food commodities. In this regard, phenolic compounds, natural molecules known for their antioxidant, anti-inflammatory, and antimicrobial properties can be right choice. Moreover, bacteriocins, antimicrobial peptides produced by various microorganisms, capable of inhibiting the growth of other bacteria, particularly closely related species can be genuine alternative. Combining phenolic compounds with bacteriocins can enhance antimicrobial effects, extending the shelf-life of food products by combating spoilage and foodborne pathogens. Despite their potential, the chemical interactions between phenolic compounds and bacteriocins, including synergistic and antagonistic effects, are not well understood. Key areas needing further research include the following: the mechanisms of action against different bacterium types, interactions with cell membranes, enzyme activity, and gene expression; the effects of environmental factors like concentration, pH, temperature, and food matrix specificity on their interactions; and methods for incorporating these compounds into food products and packaging materials to improve food safety. Additionally, the safety, toxicity, allergenicity, sensory properties, nutritional value, regulatory approval, and consumer acceptance of using phenolic compounds and bacteriocins in food products require thorough investigation.

Distinct phenotypes of salivaricin-producing Ligilactobacillus salivarius isolated from the gastrointestinal tract of broiler chickens and laying hens

Ligilactobacillus salivarius harbors bacteriocin genes in its repA-type megaplasmid, specifically salivaricin P (salP), a class IIb bacteriocin. This study aimed to differentiate 25 salP-positive Lig. salivarius strains isolated from the gastrointestinal tract (GIT) of broilers and laying hens. Results showed that 12 isolates were classified as Type A, with active bacteriocins, while the rest were Type B, with no active bacteriocins. In vitro and in silico characterization of salP bacteriocins revealed narrow-spectrum antibacterial activity against Listeria monocytogenes and Enterococcus faecalis. SalP bacteriocins were predicted as positively charged, hydrophobic, small molecular weight (α, 4.097 kDa; ß, 4.285 kDa) bacteriocins with characteristic GXXXG motif. Investigation of the salP gene cluster based on genomic data revealed that Type B strains lacked the lanT and hlyD genes that encode export proteins dedicated to the modification and extracellular transport of mature salP peptides. However, two Type B strains (B4311 and B5258) showed inhibitory activity against L. monocytogenes ATCC19114. Multiplex PCR analysis and synteny mapping analysis revealed that B4311 and B5258 strains harbored the lanT gene, highlighting the importance of LanT protein in the cleavage of leader peptide and excretion of mature peptides. Further analysis revealed that the resistance of Type B strains to salP was attributable to the presence of a dedicated immunity protein, blurring the evolutionary significance of producing active bacteriocins for competitive advantage. Additionally, the loss of export proteins occurred in a polyphyletic manner, consistent with the genetic plasticity of the repA-type megaplasmid. This suggests that the loss of lanT and hlyD is likely in the presence of limited nutritional competitors. In conclusion, the observed differences in salivaricin production of Lig. salivarius exist independent of isolation host and that Type A and Type B strains can coexist in the same environment. Finally, the functional characterization of active salP allows for a better understanding of its potential to control specific bacteria in human food and animal production.

Minimal domain peptides derived from enterocins exhibit potent antifungal activity

The antimicrobial peptide (AMP) circularized bacteriocin enterocin AS-48 produced by Enterococcus sp. exhibits broad-spectrum antibacterial activity via dimer insertion into the plasma membrane to form membrane pore structures, compromising membrane integrity and leading to bactericidal activity. A specific alpha-helical region of enterocin AS-48 has been shown to be responsible for the membrane-penetrating activity of the peptide. The canon syn-enterocin peptide library, generated using rational design techniques to have ninety-five synthetic peptide variants from the truncated, linearized, membrane-interacting domain of enterocin AS-48, was screened against three clinically relevant fungal strains: Cryptococcus neoformans, Candida albicans, and Candida auris for potential antifungal activity. Twelve peptides exhibited antifungal activity against C. neoformans, and two peptides exhibited activity against C. albicans. The fourteen active antifungal peptides were minimally cytotoxic to an immortalized human keratinocyte cell line (HaCats). Four select peptides were identified with minimum inhibitory concentrations (MICs) below 8 µM against C. neoformans. In 36-hour cell growth tests with these fungicidal peptides, fungicidal peptide no. 32 displayed inhibitory properties comparable to the leading antifungal medication fluconazole against C. neoformans. Screening of peptide no. 32 against a deletion library of C. neoformans mutants revealed that the mechanism of action of peptide no. 32 may relate to multivesicular bodies (MVBs) or polysaccharide capsule targeting. These findings importantly demonstrate that naturally derived AMPs produced by bacteria can be sourced, engineered, and modified to exhibit potent antifungal activity. Our results will contribute to the development of broad treatment alternatives to fungal infections and lend themselves to direct implications for possible treatment options for C. neoformans infections.

Multifunctional Applications of Lactic Acid Bacteria: Enhancing Safety, Quality, and Nutritional Value in Foods and Fermented Beverages

Lactic Acid Bacteria (LAB) have garnered significant attention in the food and beverage industry for their significant roles in enhancing safety, quality, and nutritional value. As starter cultures, probiotics, and bacteriocin producers, LAB contributes to the production of high-quality foods and beverages that meet the growing consumer demand for minimally processed functional and health-promoting food products. Industrial food processing, especially in the fresh produce and beverage sector, is shifting to the use of more natural bioproducts in food production, prioritizing not only preservation but also the enhancement of functional characteristics in the final product. Starter cultures, essential to this approach, are carefully selected for their robust adaptation to the food environment. These cultures, often combined with probiotics, contribute beyond their basic fermentation roles by improving the safety, nutritional value, and health-promoting properties of foods. Thus, their selection is critical in preserving the integrity, quality, and nutrition of foods, especially in fresh produce and fruits and vegetable beverages, which have a dynamic microbiome. In addition to reducing the risk of foodborne illnesses and spoilage through the metabolites, including bacteriocins they produce, the use of LAB in these products can contribute essential amino acids, lactic acids, and other bioproducts that directly impact food quality. As a result, LAB can significantly alter the organoleptic and nutritional quality of foods while extending their shelf life. This review is aimed at highlighting the diverse applications of LAB in enhancing safety, quality, and nutritional value across a range of food products and fermented beverages, with a specific focus on essential metabolites in fruit and vegetable beverages and their critical contributions as starter cultures, probiotics, and bacteriocin producers.

Nisin-relevant antimicrobial peptides: synthesis strategies and applications

Small pentacyclic peptides, represented by nisin, have been successfully utilized as preservatives in the food industry and have evolved into a paradigm for understanding the genetic structure, expression, and control of genes created by lantibiotics. Due to the ever-increasing antibiotic resistance, nisin-relevant antimicrobial peptides have received much attention, which calls for a summarization of their synthesis, modification and applications. In this review, we first provided a timeline of select highlights in nisin biosynthesis and engineering. Then, we outlined the current developments in nisin synthesis. We also provided an overview of the engineering, screening, and production of nisin-relevant antimicrobial peptides based on enzyme alteration, substrate modification, and sequence mining. Furthermore, an updated summary of applications of nisin-relevant antimicrobial peptides has been developed for food applications. Finally, this study offers insights into emerging technologies, limitations and the future development of nisin-relevant antimicrobial peptides for pathogen inhibition, food preservatives, and improved health.

Genomic Characterization of Piscicolin CM22 Produced by Carnobacterium maltaromaticum CM22 Strain Isolated from Salmon (Salmo salar)

Carnobacterium maltaromaticum is a species of lactic acid bacteria (LAB) that has been isolated from various natural environments. It is well-known for producing a diverse spectrum of bacteriocins with potential biotechnological applications. In the present study, a new psychrotolerant strain of C. maltaromaticum CM22 is reported, isolated from a salmon gut sample and producing a variant of the bacteriocin piscicolin 126 that has been named piscicolin CM22. After identification by 16S rRNA gene, this strain has been genomically characterized by sequencing and assembling its complete genome. Moreover, its bacteriocin was purified and characterized. In vitro tests demonstrated that both the strain and its bacteriocin possess antimicrobial activity against several Gram-positive bacteria of interest in human and animal health, such as Listeria monocytogenes, Clostridium perfringens, or Enterococcus faecalis. However, this bacteriocin did not produce any antimicrobial effect on Gram-negative species. The study of its genome showed the genetic structure of the gene cluster that encodes the bacteriocin, showing a high degree of homology to the gene cluster of piscicolin 126 described in other C. maltaromaticum. Although more studies are necessary concerning its functional properties, this new psychrotolerant strain C. maltaromaticum CM22 and its bacteriocin could be considered an interesting candidate with potential application in agri-food industry.

Bio-Preservation Potential and Antimicrobial Activity of Bacteriocin-Producing Lactic Acid Bacteria Isolated from Ethiopian Traditional Fermented Dairy Products

This study aimed to assess the antibacterial activity and bio-preservation capability of bacteriocin-producing LAB isolated from Ethiopian traditional fermented dairy products in raw milk from Jimma town. Bacteriocin-producing LAB were tested for their antimicrobial activity against various foodborne pathogens, including Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, and Salmonella typhimurium. The results showed that probiotic LAB isolates inhibited foodborne pathogens (E. coli, S. aureus, and L. monocytogenes), with inhibition zones ranging from 22.00 ± 0.57 to 34.13 ± 0.57. Enterococcus faecium and Lactococcus lactis demonstrated possible antagonistic effects against E. coli, while Pediococcus pentosaceus had a 34.13 ± 0.57 mm inhibitory zone against Pseudomonas aeruginosa. The isolates also showed co-aggregation potential with the pathogens, with Lactococcus lactis isolates and their combinations demonstrating the best co-aggregation capabilities against the investigated pathogens. The bio-preservative assay showed that putative probiotic isolates (L. lactis JULABE35, E. faecium JULABE 23, and P. pentosaceus JULABE05) were efficient in decreasing Listeria monocytogenes in raw milk. After 7-8 days, milk samples diagnosed with these isolates showed complete reduction of Listeria monocytogenes. The bio-preservation capability of bacteriocin-producing LAB on raw milk extended the shelf life of milk at 4 °C storage for ten days, compared to six days for milk samples without probiotic LAB. The milk samples preserved with probiotic and bacteriocin-producing isolates showed good proximate analysis, showing significant variation with milk kept without bacteriocin-producing isolates. The isolated chemicals employed in this study can be used as food additives or food preservatives, indicating potential applications in Ethiopian traditional fermented dairy products.

Turbidimetric bioassays: A solution to antimicrobial activity detection in asymptomatic bacteriuria isolates against uropathogenic Escherichia coli

Traditional bacteriocin screening methods often face limitations due to diffusion-related challenges in agar matrices, which can prevent the peptides from reaching their target organism. Turbidimetric techniques offer a solution to these issues, eliminating diffusion-related problems and providing an initial quantification of bacteriocin efficacy in producer organisms. This study involved screening the cell-free supernatant (CFS) from eight uncharacterized asymptomatic bacteriuria (ABU) isolates and Escherichia coli 83972 for antimicrobial activity against clinical uropathogenic E. coli (UPEC) strains using turbidimetric growth methods. ABU isolates exhibiting activity against five or more UPEC strains were further characterized (PUTS 37, PUTS 58, PUTS 59, S-07-4, and SK-106-1). The inhibition of the CFS by proteinase K suggested that the antimicrobial activity was proteinaceous in nature, potentially bacteriocins. The activity of E. coli PUTS 58 and SK-106-1 was enhanced in an artificial urine medium, with both inhibiting all eight UPECs. A putative microcin H47 operon was identified in E. coli SK-106-1, along with a previously identified microcin V and colicin E7 in E. coli PUTS 37 and PUTS 58, respectively. These findings indicate that ABU bacteriocin-producers could serve as viable prophylactics and therapeutics in the face of increasing antibiotic resistance among uropathogens.

In Vitro and In Silico Characterization of N-Formylated Two-Peptide Bacteriocin from Enterococcus faecalis CAUM157 with Anti-Listeria Activity

Enterococcus faecalis CAUM157 (KACC 81148BP), a Gram-positive bacteria isolated from raw cow's milk, was studied for its bacteriocin production. The antimicrobial activity of CAUM157 was attributed to a two-peptide class IIb bacteriocin with potent activity against food-borne pathogen Listeria monocytogenes and periodontal disease-causing pathogens (Prevotella intermedia KCTC 15693 T and Fusobacterium nucleatum KCTC 2488 T). M157 bacteriocins exhibit high temperature and pH stability and resist hydrolytic enzyme degradation and detergent denaturation, potentially due to their structural conformation. Based on amino acid sequence, M157A and M157B were predicted to be 5.176 kDa and 5.182 kDa in size, respectively. However, purified bacteriocins and chemically synthesized N-formylated M157 peptides both showed 5.204 kDa (M157A) and 5.209 kDa (M157B) molecular mass, confirming the formylation of the N-terminal methionine of both peptides produced by strain CAUM157. Furthermore, the strain demonstrated favorable growth and fermentation with minimal bacteriocin production when cultured in whey-based media, whereas a 1.0% tryptone or soytone supplementation resulted in higher bacteriocin production. Although Ent. faecalis CAUM157 innately harbors genes for virulence factors and antimicrobial resistance (e.g., tetracycline and erythromycin), its bacteriocin production is valuable in circumventing the need for live microorganisms, particularly in food applications for pathogen control.

Bacteriocins: potentials and prospects in health and agrifood systems

Bacteriocins are highly diverse, abundant, and heterogeneous antimicrobial peptides that are ribosomally synthesized by bacteria and archaea. Since their discovery about a century ago, there has been a growing interest in bacteriocin research and applications. This is mainly due to their high antimicrobial properties, narrow or broad spectrum of activity, specificity, low cytotoxicity, and stability. Though initially used to improve food quality and safety, bacteriocins are now globally exploited for innovative applications in human, animal, and food systems as sustainable alternatives to antibiotics. Bacteriocins have the potential to beneficially modulate microbiota, providing viable microbiome-based solutions for the treatment, management, and non-invasive bio-diagnosis of infectious and non-infectious diseases. The use of bacteriocins holds great promise in the modulation of food microbiomes, antimicrobial food packaging, bio-sanitizers and antibiofilm, pre/post-harvest biocontrol, functional food, growth promotion, and sustainable aquaculture. This can undoubtedly improve food security, safety, and quality globally. This review highlights the current trends in bacteriocin research, especially the increasing research outputs and funding, which we believe may proportionate the soaring global interest in bacteriocins. The use of cutting-edge technologies, such as bioengineering, can further enhance the exploitation of bacteriocins for innovative applications in human, animal, and food systems.

Safety and Beneficial Properties of Bacteriocinogenic Lactococcus lactis and Pediococcus pentosaceus Strains, and Their Effect Versus Oral Cavity Related and Antibiotic-Resistant Pathogens

Pediococcus pentosaceus 732, Lactococcus lactis subsp. lactis 431, and Lactococcus lactis 808, bacteriocinogenic strains previously isolated from kimchi and banana, were investigated for their safety, beneficial properties and in vitro inhibition of pathogens such as Listeria monocytogenes ATCC 15313 and Staphylococcus simulans KACC 13241 and Staphylococcus auricularis KACC 13252. The results of performed physiological, biochemical, and biomolecular tests suggest that these strains can be deemed safe, as no virulence genes were detected in their DNA. Notably, only the gad gene associated with GABA production was identified in the DNA isolated of Lc. lactis 808 and Lc. lactis subsp. lactis 431 strains. All tested LAB strains exhibited γ-hemolysins and were non-producers of gelatinase and biogenic amines, which suggested their safety potential. Additionally, they were relatively susceptible to antibiotics except for streptomycin, tobramycin, and vancomycin for Pd. pentosaceus 732. The growth of Pd. pentosaceus 732, Lc. lactis subsp. lactis 431, and Lc. lactis 808 and their survival were minimally affected by up to 3% ox bile and low pH (except pH 2.0 and 4.0). Moreover, these LAB strains were not inhibited by various commercial extracts as well as most of the tested medications tested in the study. They did not produce proteolytic enzymes but exhibited production of D/L-lactic acid and β-galactosidase. They were also hydrophilic. Furthermore, their survival in artificial saliva, gastric simulation, and enteric passage was measured followed by a challenge test to assess their ability to inhibit the selected oral pathogens in an oral saliva model conditions.

Plasmid-Associated Bacteriocin Produced by Pediococcus pentosaceus Isolated from Smoked Salmon: Partial Characterization and Some Aspects of his Mode of Action

Strain ST3Ha, isolated from commercially available smoked salmon, was identified as Pediococcus pentosaceus based on biochemical and physiological tests and 16S rRNA sequencing. Strain ST3Ha produces a class IIa bacteriocin active against lactic acid bacteria, Listeria monocytogenes and Enterococcus faecalis. The antimicrobial peptide was inactivated by proteolytic enzymes, confirming his proteinaceous nature, but was not affected when treated with α-amylase, SDS, Tween 20, Tween 80, urea, and EDTA. No change in activity was recorded after 2 h at pH values between 2.0 and 9.0 and after treatment at 100 °C for 120 min or 121 °C for 15 min. The mode of action against Listeria ivanovii subsp. ivanovii ATCC 19119 and E. faecalis ATCC 19443 was bactericidal, resulting in cell lyses and enzyme leakage. The highest level of activity (1.6 × 106 AU/mL) was recorded when cells were grown at 37 °C or 30 °C in MRS broth (pH 6.5). Antimicrobial peptide ST3Ha adsorbs at high levels to the sensitive test organisms on strain-specific manner and depending on incubation temperature, environmental pH, and presence of supplemented chemicals. Based on PCR analysis, P. pentosaceus ST3Ha harbor a 1044-bp plasmid-associated fragment corresponding in size to that recorded for pediocin PA-1. Sequencing of the fragment revealed a gene identical to pedB, reported for pediocin PA-1. The combined application of the low levels (below MIC) of ciprofloxacin and bacteriocin ST3Ha results in the synergetic effect in the inhibition of L. ivanovii subsp. ivanovii ATCC 19119. Expressed by P. pentosaceus ST3Ha, bacteriocin was characterized as low cytotoxic, a characteristic relevant for its application in food industry and/or in human and veterinary medical practices.

Blue Biotechnology: Marine Bacteria Bioproducts

The ocean is the habitat of a great number of organisms with different characteristics. Compared to terrestrial microorganisms, marine microorganisms also represent a vast and largely unexplored reservoir of bioactive compounds with diverse industrial applications like terrestrial microorganisms. This review examines the properties and potential applications of products derived from marine microorganisms, including bacteriocins, enzymes, exopolysaccharides, and pigments, juxtaposing them in some cases against their terrestrial counterparts. We discuss the distinct characteristics that set marine-derived products apart, including enhanced stability and unique structural features such as the amount of uronic acid and sulfate groups in exopolysaccharides. Further, we explore the uses of these marine-derived compounds across various industries, ranging from food and pharmaceuticals to cosmetics and biotechnology. This review also presents a broad description of biotechnologically important compounds produced by bacteria isolated from marine environments, some of them with different qualities compared to their terrestrial counterparts.

Anti-Listerial Activity of Bacteriocin-like Inhibitory Substance Produced by Enterococcus lactis LBM BT2 Using Alternative Medium with Sugarcane Molasses

Listeria monocytogenes is a foodborne pathogen that contaminates food-processing environments and persists within biofilms on equipment, thus reaching final products by cross-contamination. With the growing demand for clean-label products, the search for natural antimicrobials as biopreservants, such as bacteriocins, has shown promising potential. In this context, this study aimed to evaluate the anti-listerial action of bacteriocins produced by Enterococcus lactis LBM BT2 in an alternative medium containing sugarcane molasses (SCM). Molecular analyses were carried out to characterize the strain, including the presence of bacteriocin-related genes. In the kinetic study on SCM medium E. lactis, LBM BT2 showed biomass and bacteriocin productions similar to those observed on a sucrose-based medium (control), highlighting the potential of the sugarcane molasses as a low-cost substrate. Stability tests revealed that the molecule remained active in wide ranges of pH (4-10) and temperature (60-100 °C). Furthermore, the proteolytic treatment reduced the biomolecule's antimicrobial activity, highlighting its proteinaceous nature. After primary purification by salting out and tangential flow filtration, the bacteriocin-like inhibitory substance (BLIS) showed bacteriostatic activity on suspended L. monocytogenes cells and against biofilm formation at a concentration of 0.625 mg/mL. These results demonstrate the potential of the produced BLIS as a biopreservative in the food industry.

Antibacterial mode of action of garviecin LG34 against Gram-negative bacterium Salmonella typhimurium

Garviecin LG34 produced by Lactococcus garvieae LG34 exhibits wide-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. This work aimed at clarifying the antibacterial mode of action of garviecin LG34 against Gram-negative bacterium Salmonella typhimurium. To determine the concentration for the bacteriocin antimicrobial mode experiments, the minimum inhibitory concentration of garviecin LG34 against S. typhimurium CICC21484 was determined as 0.25 mg/ml. Garviecin LG34 decreased the viable count of S. typhimurium CICC21484 and its antibacterial activity was the dose and time dependant. Garviecin LG34 led to the dissipation of transmembrane potential, the rise in the extracellular conductivity, UV-absorbing material at 260 nm, and LDH level of S. typhimurium CICC21484. Scanning electron micrographs results shown that garviecin LG34 cause dramatic deformation and fragmentation including the flagellum shedding, pores formation in surface, and even completely breakage of S. typhimurium cell. Moreover, garviecin LG34 decreased the intracellular ATP level. The results of this study demonstrated that garviecin LG34 can destroy cell structure, increase membrane permeability of S. typhimurium, thereby might be used as biopreservative for treating food borne and salmonellosis resulting from Gram-negative bacterium S. typhimurium.

Nanotechnological interventions in bacteriocin formulations - advances, and scope for challenging food spoilage bacteria and drug-resistant foodborne pathogens

Food spoilage bacteria (FSB) and multidrug-resistant (MDR) foodborne pathogens have emerged as one of the principal public health concerns in the twenty first century. The harmful effects of FSB lead to economic losses for the food industries. Similarly, MDR foodborne pathogens are accountable for multiple illnesses and pose a threat to consumers. Therefore, there is an urgent need to establish effective formulations for successful application against such microorganisms. In this context, the fusion of knowledge from biotechnology and nanotechnology can explore endless possibilities in the development of innovative formulations against FSB and foodborne pathogens. The current review critically examines the application of bacteriocins in the food industry and the use of nanomaterials to enhance the antimicrobial activity, stability, and precision in the target delivery of bacteriocins. This review also explores the technologies involved in the development of bacteriocin-based nanoformulations and their action against FSB and MDR foodborne pathogens, offering new possibilities in preservation technologies and addressing food safety issues in the food industry. The review highlights the challenges in the commercialization and technoeconomical feasibility of nanobacteriocin. Overall, it provides essential information and interpretation about nanotechnological advancements in bacteriocin formulation action against FSB and foodborne pathogens and future scopes.

Nanostructured Antimicrobials for Quality and Safety Improvement in Dairy Products

In the food sector, one of the most important economic activities is the dairy industry, which has been facing many challenges in order to meet the increasing demand by consumers for natural and minimally processed products with high quality. In this sense, the application of innovative and emerging technologies can be an interesting alternative, for example, the use of nanotechnology in packaging and as delivery systems. This technology has the potential to improve the quality and safety of dairy products, representing an interesting approach for delivering food preservatives and improving the mechanical, barrier and functional properties of packaging. Several applications and promising results of nanostructures for dairy product preservation can be found throughout this review, including the use of metallic and polymeric nanoparticles, lipid-based nanostructures, nanofibers, nanofilms and nanocoatings. In addition, some relevant examples of the direct application of nanostructured natural antimicrobials in milk and cheese are presented and discussed, as well as the use of milk agar as a model for a preliminary test. Despite their high cost and the difficulties for scale-up, interesting results of these technologies in dairy foods and packaging materials have promoted a growing interest of the dairy industry.

Lactiplantibacillus paraplantarum BPF2 and Pediococcus acidilactici ST6, Two Bacteriocinogenic Isolated Strains from Andalusian Spontaneous Fermented Sausages

Traditional spontaneously fermented foods are well known for their sensory and safety properties, which is mainly due to their indigenous microflora. Within this group of food, Mediterranean dry-cured sausages stand out as a significant source of lactic-acid bacterial strains (LAB) with biotechnological properties, such as their antimicrobial activity. The aim of this study was to investigate the biodiversity of antagonistic LAB strains from different Andalusian traditional sausages, such as salchichón and chorizo. First, a screening was carried out focusing on the antimicrobial activity against foodborne pathogens, such as Listeria monocytogenes, Escherichia coli, Clostridium perfringens, and Staphylococcus aureus, selecting two strains due to their higher antibiosis properties, both in agar and liquid media. These bacteria were identified as Lactiplantibacillus paraplantarum BPF2 and Pediococcus acidilactici ST6. In addition, genomic studies confirmed the presence of certain structural genes related to the production of bacteriocins. Finally, the culture supernatants of both strains were purified and analyzed by LC-MS/MS, obtaining the relative molecular mass and the amino acid sequence and identifying the peptides as the bacteriocins Pediocin-PA and Leucocin K. In conclusion, genomes and antimicrobial substances of P. acidilactici ST6, a Pediocin-PA producer, and Lpb. paraplantarum BPF2, a Leucocin K producer, isolated from Andalusian salchichón and chorizo, respectively, are presented in this work. Although further studies are required, these strains could be used alone or in combination as starters or protective cultures for the food industry.

After a century of nisin research - where are we now?

It is almost a century since nisin was discovered in fermented milk cultures, coincidentally in the same year that penicillin was first described. 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 our understanding of the genetic organization, expression, and regulation of genes involved in lantibiotic biosynthesis-one of the few cases of extensive post-translation modification in prokaryotes. Recent developments in understanding the complex biosynthesis of nisin have shed light on the cellular location of the modification and transport machinery and the co-ordinated series of spatio-temporal events required to produce active nisin and provide resistance and immunity. The continued unearthing of new natural variants from within human and animal gastrointestinal tracts has sparked interest in the potential application of nisin to influence the microbiome, given the growing recognition of the role the gastrointestinal microbiota plays in health and disease. Moreover, interdisciplinary approaches have taken advantage of biotechnological advancements to bioengineer nisin to produce novel variants and expand nisin functionality for applications in the biomedical field. This review will discuss the latest progress in these aspects of nisin research.

Immunomodulatory Properties of Probiotics and Their Derived Bioactive Compounds

Immune system modulation is an intriguing part of scientific research. It is well established that the immune system plays a crucial role in orchestrating cellular and molecular key mediators, thus establishing a powerful defense barrier against infectious pathogens. Gut microbiota represent a complex community of approximately a hundred trillion microorganisms that live in the mammalian gastrointestinal (GI) tract, contributing to the maintenance of gut homeostasis via regulation of the innate and adaptive immune responses. However, impairment in the crosstalk between intestinal immunity and gut microbiota may reflect on detrimental health issues. In this context, many studies have indicated that probiotics and their bioactive compounds, such as bacteriocins and short chain fatty acids (SCFAs), display distinct immunomodulatory properties through which they suppress inflammation and enhance the restoration of microbial diversity in pathological states. This review highlights the fundamental features of probiotics, bacteriocins, and SCFAs, which make them ideal therapeutic agents for the amelioration of inflammatory and autoimmune diseases. It also describes their underlying mechanisms on gut microbiota modulation and emphasizes how they influence the function of immune cells involved in regulating gut homeostasis. Finally, it discusses the future perspectives and challenges of their administration to individuals.

Design of Lactococcus lactis Strains Producing Garvicin A and/or Garvicin Q, Either Alone or Together with Nisin A or Nisin Z and High Antimicrobial Activity against Lactococcus garvieae

Lactococcus garvieae is a main ichthyopathogen in rainbow trout (Oncorhynchus mykiss, Walbaum) farming, although bacteriocinogenic L. garvieae with antimicrobial activity against virulent strains of this species have also been identified. Some of the bacteriocins characterized, such as garvicin A (GarA) and garvicin Q (GarQ), may show potential for the control of the virulent L. garvieae in food, feed and other biotechnological applications. In this study, we report on the design of Lactococcus lactis strains that produce the bacteriocins GarA and/or GarQ, either alone or together with nisin A (NisA) or nisin Z (NisZ). Synthetic genes encoding the signal peptide of the lactococcal protein Usp45 (SP_usp45), fused to mature GarA (lgnA) and/or mature GarQ (garQ) and their associated immunity genes (lgnI and garI, respectively), were cloned into the protein expression vectors pMG36c, which contains the P₃₂ constitutive promoter, and pNZ8048c, which contains the inducible P_nisA promoter. The transformation of recombinant vectors into lactococcal cells allowed for the production of GarA and/or GarQ by L. lactis subsp. cremoris NZ9000 and their co-production with NisA by Lactococcus lactis subsp. lactis DPC5598 and L. lactis subsp. lactis BB24. The strains L. lactis subsp. cremoris WA2-67 (pJFQI), a producer of GarQ and NisZ, and L. lactis subsp. cremoris WA2-67 (pJFQIAI), a producer of GarA, GarQ and NisZ, demonstrated the highest antimicrobial activity (5.1- to 10.7-fold and 17.3- to 68.2-fold, respectively) against virulent L. garvieae strains.

Biochemical and Genomic Characterization of Two New Strains of Lacticaseibacillus paracasei Isolated from the Traditional Corn-Based Beverage of South Africa, Mahewu, and Their Comparison with Strains Isolated from Kefir Grains

Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) is a nomadic lactic acid bacterium (LAB) that inhabits a wide variety of ecological niches, from fermented foodstuffs to host-associated microenvironments. Many of the isolated L. paracasei strains have been used as single-strain probiotics or as part of a symbiotic consortium within formulations. The present study contributes to the exploration of different strains of L. paracasei derived from non-conventional isolation sources-the South African traditional fermented drink mahewu (strains MA2 and MA3) and kefir grains (strains KF1 and ABK). The performed microbiological, biochemical and genomic comparative analyses of the studied strains demonstrated correlation between properties of the strains and their isolation source, which suggests the presence of at least partial strain adaptation to the isolation environments. Additionally, for the studied strains, antagonistic activities against common pathogens and against each other were observed, and the ability to release bioactive peptides with antioxidant and angiotensin I-converting enzyme inhibitory (ACE-I) properties during milk fermentation was investigated. The obtained results may be useful for a deeper understanding of the nomadic lifestyle of L. paracasei and for the development of new starter cultures and probiotic preparations based on this LAB in the future.