Natural Antimicrobial Substances Research Articles

Revealing antibiotic resistance's ancient roots: insights from pristine ecosystems.

The prevailing belief that antibiotic resistance mechanisms emerged with human antibiotic use has been challenged. Evidence indicates that some antibiotic resistance genes (ARGs) have a long evolutionary history, predating the advent of antibiotics in human medicine, thereby demonstrating that resistance is an ancient phenomenon. Despite extensive surveys of resistance elements in environments impacted by human activity, limited data are available from remote and pristine habitats. This minireview aims to compile the most relevant research on the origins and evolution of ARGs in these habitats, which function as reservoirs for ancient resistance mechanisms. These studies indicate that ancient ARGs functionally similar to modern resistance genes, highlighting the general role of natural antimicrobial substances in fostering the evolution and exchange of diverse resistance mechanisms through horizontal gene transfer over time. This minireview underscores that antibiotic resistance was present in ancestral microbial communities and emphasizes the ecological role of antibiotics and resistance determinants. Understanding ancient ARGs is crucial for predicting and managing the evolution of antibiotic resistance. Thus, these insights provide a foundational basis for developing new antibiotics and strategies for microbial resistance management.

Recent advances in physical/chemical methods as alternatives to SO2 for winemaking: Principles, challenges and perspectives

Sulphur dioxide (SO2) is commonly used in the wine industry to prevent oxidation and maintain microbial stability. However, it can harm consumer health, resulting in a growing demand for chemical-free wine. Therefore, reducing or eliminating the addition of SO2 has become a prevalent trend in the wine industry. In recent years, researchers have made significant progress in finding alternative methods to SO2. This review provides the latest research progress on innovative methods proposed to replace SO2 in winemaking. These include dimethyl dicarbonate, silver nanoparticles, lysozyme, chitosan, phenolic compounds, membrane filtration, ultrasound, ultraviolet irradiation, high pressure, and pulsed electric field. However, these individual antimicrobial methods do not possess the same comprehensive antimicrobial and antioxidant properties as SO2. In the proposed strategy, a promising alternative to SO2 could be to combine physical sterilization technologies with antimicrobial substances. In particular, gentle physical techniques such as pulsed electric field in synergy with natural grape polyphenols can maintain the microbiological stability of wine without the introduction of foreign aid substances, while enhancing the wine's antioxidant properties. In conclusion, while replacing SO2 entirely for wine production remains challenging, the combination of physical sterilization technologies and natural antimicrobial substances shows promise as a viable alternative.

Effectiveness of Essential Oil Component Cocrystals Against Food Spoilage Bacteria

AbstractImproving food preservation technologies is a key aspect in the struggle to reduce global food waste, and natural antimicrobial substances, such as essential oil (EO) components represent very promising food preserving agent. However, their intrinsic chemico‐physical properties, such as the low melting point, low water solubility and high volatility, pose some practical difficulties in exploiting them for practical applications. Cocrystallization is used to stabilize liquid or volatile EO components providing them whit a crystalline environment, thus improving their potential application as antibacterial agents. Five EO active ingredients (THY = thymol, CAR = carvacrol, EUG = eugenol, CAD = trans‐cinnamaldehyde, and VAN = o‐vanillin) and two coformers (INA = Isonicotinamide, and HBA = 4‐hydroxybenzoic acid) have been combined and the corresponding cocrystals have been studied for their potential inhibiting effect against four food spoilage bacteria (Bacillus thuringiensis, Enterobacter cloacae, Pseudomonas fluorescens, and Serratia marcescens). The structures of the five cocrystals have been used to derive structure‐activity relationships in terms of release energy of the active ingredients form the crystalline environment, and a correlation has been derived with the Intermolecular Interaction Energies of the EO molecules.

Clinical Trial Findings and Drug Development Challenges for Curcumin in Infectious Disease Prevention and Treatment.

Since ancient times, turmeric, scientifically known as Curcuma longa, has been renowned for its therapeutic properties. Recently, extensive documentation has highlighted the prevalence of microbial diseases without effective treatments, the increased expense of certain antimicrobial medications, and the growing occurrence of antimicrobial drug resistance. Experts predict that drug resistance will emerge as a significant global cause of death by the middle of this century, thereby necessitating intervention. Curcumin, a major curcuminoid molecule, has shown extensive antimicrobial action. Improving and altering the use of natural antimicrobial agents is the most effective approach to addressing issues of targeted specificity and drug resistance in chemically synthesized medicines. Further research is required to explore the efficacy of curcumin and other natural antimicrobial substances in combating microbial infections. The solubility and bioavailability of curcumin impede its antimicrobial capability. To enhance curcumin's antimicrobial effectiveness, researchers have recently employed several methods, including the development of curcumin-based nanoformulations. This review seeks to compile the latest available literature to assess the advantages of curcumin as a natural antimicrobial agent (particularly antiviral and antibacterial) and strategies to enhance its medical efficacy. The future application of curcumin will help to alleviate microbial infections, thereby promoting the sustainability of the world's population.

Interventions based on alternative and sustainable strategies for postharvest control of anthracnose and maintain quality in tropical fruits.

Colletotrichum spp. is a phytopathogen causing anthracnose in a variety of tropical fruits. Strategies used to control postharvest diseases in tropical fruits typically rely on the use of synthetic fungicides, which have stimulated the emergence of resistant pathogens. Safer alternative strategies to control anthracnose in tropical fruits have been described in the literature. This review presents and discusses the main innovative interventions concerning the application of sustainable alternative strategies in the postharvest control of pathogenic Colletotrichum species in tropical fruits, with a particular emphasis on the studies published in the last 5 years. The available studies have shown the use of various methods, including physical barriers, natural antimicrobials, and biological control with antagonistic microorganisms, to reduce anthracnose lesion severity and incidence in tropical fruits. The available literature showed high inhibitory activity in vitro, reduced anthracnose incidence and lesion diameter, and total disease inhibition in tropical fruits. Most studies focused on the inhibition of Colletotrichum gloeosporioides on avocado, papaya, and mango, as well as of Colletotrichum musae on banana; however, the inhibition of other Colletotrichum species was also demonstrated. The application of emerging sustainable alternative methods, including natural antimicrobial substances, also stimulated the induction of defense systems in tropical fruits, including enzymatic activity, such as polyphenol oxidase, peroxidase, and phenylalanine ammonia-lyase. The retrieved data helped to understand the current state of the research field and reveal new perspectives on developing efficient and sustainable intervention strategies to control pathogenic Colletotrichum species and anthracnose development in tropical fruits.

An Overview of Advanced Antimicrobial Food Packaging: Emphasizing Antimicrobial Agents and Polymer-Based Films.

The food industry is increasingly focused on maintaining the quality and safety of food products as consumers are becoming more health conscious and seeking fresh, minimally processed foods. However, deterioration and spoilage caused by foodborne pathogens continue to pose significant challenges, leading to decreased shelf life and quality. To overcome this issue, the food industry and researchers are exploring new approaches to prevent microbial growth in food, while preserving its nutritional value and safety. Active packaging, including antimicrobial packaging, has gained considerable attention among current food packaging methods owing to the wide range of materials used, application methods, and their ability to protect various food products. Both direct and indirect methods can be used to improve food safety and quality by incorporating antimicrobial compounds into the food packaging materials. This comprehensive review focuses on natural and synthetic antimicrobial substances and polymer-based films, and their mechanisms and applications in packaging systems. The properties of these materials are compared, and the persistent challenges in the field of active packaging are emphasized. Specifically, there is a need to achieve the controlled release of antimicrobial agents and develop active packaging materials that possess the necessary mechanical and barrier properties, as well as other characteristics essential for ensuring food protection and safety, particularly bio-based packaging materials.

Single and combined application of bacteriophage and cinnamon oils against pathogenic Listeria monocytogenes in milk and smoked salmon

Nowadays, the discovery of alternative natural antimicrobial substances such as bacteriophages, essential oils, and other physical and chemical agents is developing in the food industry. In this study, nine bacteriophages were isolated from various parts of raw chickens and exhibited lytic activities against L. monocytogenes and various Listeria spp. The characterization of phage vB_LmoS-PLM9 was stable at 4 to 50 °C and pH range from 4 to 10. Phage vB_LmoS-PLM9 had a circular, double-stranded genomic DNA with 38,345 bp having endolysin but no antibiotic resistance or virulence genes. Among the eight essential oils tested at 10 %, cinnamon bark, and cassia oils showed the strongest antilisterial activities. The combined use of phage vB_LmoS-PLM9 and cinnamon oils indicated higher efficiency than single treatments. The combination of phage (MOI of 10) and both cinnamon oils (0.03 %) reduced the viable counts of L. monocytogenes and inhibited the regrowth of resistant cell populations in broth at 30 °C. Furthermore, treatment with the combination of phage (MOI of 100) and cinnamon oil (0.125 %) was effective in milk, especially at 4 °C by reducing the viable count to less than lower limit of detection. These results suggest combining phage and cinnamon oil is a potential approach for controlling L. monocytogenes in milk.

Antifungal efficacy of natural antimicrobial substances during the fermentation and storage of hardaliye

Hardaliye is a non-alcoholic traditional fermented beverage produced using black grapes, mustard seeds, sour cherry leaves, and sodium benzoate. In this study, the effect of using plant materials (quince leaves, green tea, mulberry leaves, linden flowers, horseradish roots) as an alternative to sodium benzoate for inhibiting yeast growth to produce additive-free hardaliye was investigated. Hardaliye samples were produced using the selected test materials, microbiological and chemical analyses were performed during fermentation (20 °C for 18 days) and storage (4 °C for 2 months) periods. Additionally, the antifungal effects of test material extracts against Saccharomyces cerevisiae in grape juice and Malt Extract Broth (MEB), as well as the survival of S. cerevisiae in grape juice containing plant materials were examined. Only mustard seed extract had inhibitory and fungicidal effects at 25 mg/mL on S. cerevisiae in MEB among the tested plant material extracts and the effect increased when used in combination with grape juice. The total phenolic contents of the hardaliye samples were in the range of 2119.26–8653.33 mg gallic acid equivalents (GAE)/L, and antioxidant activities were in the range of 30.24–93.15%. The numbers of S. cerevisiae decreased below the detection limit (<1 log CFU/mL) after 1 day in grape juice containing horseradish (5%), mustard seeds (1.5%) or sodium benzoate (0.1%). This study indicated that crushed mustard seeds at increased concentrations (1.5%), mustard seeds water extract (7.5 mg/mL), or horseradish roots (5%) have the potential to be used in the production of hardaliye as an alternative to sodium benzoate.

Protein‐based active films: Raw materials, functions, and food applications

AbstractBiopolymer packaging materials are an emerging trend in food packaging due to their degradability, nontoxicity, low cost, and low environmental stress; moreover, some properties of biopolymer packaging are better than those of traditional packaging. Proteins are a type of natural biopolymer packaging film matrix, and enhancing the packaging properties of proteins has been a focus of research. Preparing protein‐active packaging films by adding natural active substances with antimicrobial and antioxidant properties and nanoparticles to protein‐based films to provide more significant antimicrobial, antioxidant, and UV‐blocking effects is essential in food packaging and demonstrates the potential of using proteins in active food packaging applications. In recent years, the origin of natural actives, their mechanism of action, and their release from active packaging films have attracted much attention. In this review, we provide a comprehensive overview of protein film matrices for active packaging, natural antimicrobial agents, and natural antioxidants and discuss the potential of such active films in the packaging field. The sources of natural antimicrobial active substances and natural antioxidant active substances in packaging materials, their mechanisms of action, and their effects after being used to modify protein active films are summarized. The biorelease functions of protein active films with antimicrobial and antioxidant effects and their applications for various types of food are highlighted to understand the current effects of protein active films in food packaging.

Streptomyces rapamycinicus HCD1–10: An effective biocontrol actinomycetes against postharvest Chinese flat peach brown rot caused by Monilinia fructicola

Monilinia spp. causing brown rot are fungal pathogens producing severe losses in worldwide stone fruit production, with high economic relevance (M€ 1.7/year). There are three main fungal species: Monilinia laxa, M. fructigena and M. fructicola. The pathogen infects aerial parts of host plants with a variety of symptoms, including blighting of blossoms, cankers on woody tissues and rotting of fruits, although the prevalent fruit losses are in the postharvest phase. Fungicide sprays in pre- and postharvest periods are usually used to control Monilinia spp. but, in Europe, no fungicide fruit treatments are allowed after harvest. Many studies conducted in recent years have defined three main research fields within the alternative methods for postharvest brown rot control: (1) biological control sensu strictum with microbial antagonists; (2) use of natural bioactive compounds; and (3) use of physicochemical methods. Although the reviewed results have reported a significant reduction of pesticide use, a multidisciplinary approach is recommended in the future, where biological products will be combined with low-risk chemical fungicides, natural antimicrobial substances and other physical means for an integrated strategy to control brown rot.

Evaluation of Natural Antimicrobial Substances Blend as a Replacement for Antibiotic Growth Promoters in Broiler Chickens: Enhancing Growth and Managing Intestinal Bacterial Diseases.

In recent years, commercial use of antibiotic growth promoter (AGP) has restrictions due to drug resistance against intestinal pathogenic bacteria: Escherichia coli, Salmonella, and Clostridium perfringens. Currently there is no single non-antibiotic treatment approach that is effective against intestinal illnesses in broiler chicken. Hence, present study aimed to analyze efficacy of blend of natural antimicrobial substances (probiotics, prebiotics, organic acids, and essential oils blend named as AGPR) as replacers of AGPs (BMD and CTC) for promoting growth and controlling bacterial diseases in aforementioned three microbes challenged broiler chickens. Effects of treatments (5) and microbes (3) on growth and health performances in experimental birds were analyzed using two factorial ANOVA. Health performance like pathogen loads, morbidity and mortality was considerably reduced by AGPR. Similarly small intestine villi morphometry, nutrition utilization, serum immune response, and carcass yield, was improved significantly by AGPR equivalent to AGPs. Further, growth performance like body weight gain, feed efficiency was also improved by AGPR compared to control but, non-significantly. Among three microbes, E. coli infections had higher morbidity and mortality rates. It was concluded that AGPR blend could be used to improve growth and control the intestinal bacterial infections in broiler chickens as an alternative for AGPs.

The prospect of using nisin for pre-milking treatment of the udder of cows

Bacteriocins, in particular, nisin, are increasingly used for the development of sanitizing agents along with natural antimicrobial substances, such as organic acids, essential oils, alcohols, and others. The purpose of the work was to investigate the bactericidal effect of nisin on test cultures of microorganisms that cause mastitis in cows for its use in means for pre-milking treatment of the udder in combination with lactic acid. The minimum inhibitory concentration was studied on test cultures of Staphylococcus aureus (ATCC 25923), Escherichia coli (055К59 №3912/41) and Streptococcus uberis (field strain) by the method of serial dilutions with exposures of 30 seconds and 10 minutes. In the experiment was used nisin produced by Glory Chem Co., Ltd. (China), lactic acid food 80 % solution (“Klebrig”, Belgium). It was established that the minimum inhibitory concentration of nisin after exposure for 30 seconds on S. aureus cultures was 1.0 % and Str. uberis – 0.125 %. Nisin at the content of 2 % and 1 % in the solution did not show the minimum inhibitory concentration on E. coli cultures within 30 seconds, but inhibited 91.7 and 82.3 % of the microflora, respectively, at this concentration. It was found that the minimum inhibitory concentration of lactic acid after exposure for 30 seconds on S. aureus and E. coli cultures was 2 %, and on Str. uberis – 1 %. At the same time, lactic acid diluted below the minimum inhibitory concentration, in particular, 1 % and 0.5 %, inhibited 98.9–96.5 % of microorganisms in the solution, which may be sufficient for its use in means for processing the udder of cows before milking and at lower concentration. The study of the bactericidal effect by the well method showed that nisin exhibits a synergistic bactericidal effect with lactic acid and can be used in combination to create a means for pre-milking treatment of the udder of cows. Therefore, in order to create means for pre-milking treatment of the skin of udders of cows, it is necessary that the working concentration of nisin be from 0.5 to 1.0 %, and lactic acid from 1 to 2 %.

Natural antibacterial membranes prepared using Schisandra chinensis extracts and polyvinyl alcohol in an environment-friendly manner

Foodborne pathogens can cause food spoilage and lead to food safety issues. In recent years, food packaging has received a lot of attention. Traditional packaging membranes are non-biodegradable and remain in the environment for a long time. In this study, natural antimicrobial substances were extracted from Schisandra chinensis by a green extraction process using distilled water as the solvent, and the effects of different treatment on the antimicrobial activity of the extract were compared. At the same time, four types of Schisandra chinensis antimicrobial membranes were prepared using polyvinyl alcohol (PVA) as the substrate. The whole extraction and membrane preparation process did not involve organic solvents, making the process green and environment friendly. Material characterization included inverted biological microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), tensile strength test, pore size measurement, water uptake test, etc. Among them, no extract particles were observed with the naked eye on the surfaces of MⅡ and MⅣ. MⅡ has a uniformly transparent, nearly colorless morphology and is the most tensile. MⅣ surface is flat and smooth, the microstructure is dense and uniform. At the same time, the four types of membranes were tested against common pathogenic bacteria for 12 h, and the OD600 trend revealed the excellent antimicrobial activity of the membranes against S. aureus, MRSA, E. coli, and L. monocytogenes. The membranes could also be reused at least once. This study provides a new idea for preparing natural plant-based antimicrobial membranes.

Antimicrobial Effects of Edible Mixed Herbal Extracts on Oral Microorganisms: An In Vitro Study.

Background and Objectives: The oral cavity is inhabited by pathogenic bacteria, whose growth can be inhibited by synthetic oral drugs, including antibiotics and other chemical compounds. Natural antimicrobial substances that elicit fewer negative side effects may serve as alternatives to synthetic agents for long-term use. Thus, the aim of this study was to evaluate the effects of edible mixed herbal extracts on the growth of oral pathogenic bacteria. Materials and Methods: The yield of each herbal extract was as follows: 5% Schizonepeta tenuifolia Briq (STB), 10.94% Mentha piperascens (MP), 5.47% Acanthopanax sessiliflorus Seem (AS), and 10.66% Glycyrrhiza uralensis (GU). The herbal extracts used included 0.5 mg/mL STB, 1.5 mg/mL MP, 1.5 mg/mL AS, and 2.0 mg/mL GU. Antimicrobial tests, morphological analyses (using scanning electron microscopy), microbial surface hydrophobicity measurements, and oral malodor reduction tests were performed using each extract. Statistical analyses were performed with IBM® SPSS® (version 24), using paired t-tests. Results: The mixed herbal extracts significantly inhibited the growth of Streptococcus mutans, Enterococcus faecalis, Candida albicans, and Porphyromonas gingivalis compared to the control (p < 0.001). Scanning electron microscopy results further revealed altered cellular morphology in the groups treated with the mixed herbal extracts. Additionally, the hydrophobicity assay results showed that the mixed herbal extracts reduced the oral adhesion capacities of bacteria (p < 0.001). Administration of the mixed herbal extracts also reduced the levels of volatile sulfur compounds, the main contributors to oral malodor (p < 0.001). Conclusions: Edible mixed herbal extracts can effectively eliminate oral pathogens and may be useful for improving oral health. The herbal extracts used were effective against all species of oral pathogens studied in this report.

ACOMPARATIVE STUDY OF ANTIMICROBIAL ACTIVITY OF MELALEUCA ALTERNIFOLIA,ACHILLEA MILLEFOLIUMAND CINNNAMOMUM CAMPHORAVAGINAL SUPPOSITORIES

Vaginal inflammation represents a heterogeneous group of disorders caused by infection, inflammation, or disruption of vaginal microflora. The most common causes of vaginal infection are Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, Escherichia coliand Candida albicans. Antibiotic resistance is a major global problem, which can be mitigated by using natural antimicrobial substances such as essential oils. Each essential oil has an extremely complex composition (some essential oilshave over 200 components), which prevents microorganisms from developing resistance. Therefore, essential oils retain their effects.The aim of our study was to investigate antibacterial activity Melaleuca alternifolia, Achillea millefoliumand Cinnamomumcamphoravaginal suppositories, and see which essential oil has the strongest potential to be used as active ingredient for vaginal infections.The antimicrobial activity of the vaginal suppositories was examined using the disk diffusion method. Standard bacterial strains were used for the ATCC collection: Staphylococcus aureus (S. aureus) ATCC 25923, Enterococcus faecalis (E. faecalis)ATCC 51299, Escherichia coli (E. coli)ATCC 25922, Candida albicans (C. albicans)ATCC 10231.The results showed that Melaleuca alternifolia essential oil has an antimicrobial effect on all tested strains, with the strongest effect on Candida albicans(ZI 22.7 mm). Achillea millefoliumessential oil had no effect on Enterococcus faecalis, whereas Cinnamomum camphoraessential oil did not show zones of inhibition of Candida albicans.KEYWORDS:vaginal suppository, Melaleuca alternifolia, Achillea millefolium, Cinnamomum camphora,antimicrobial activity

Phytopathogenic Fungal Growth Inhibition by Actinomycetes Isolated from the Rhizosphere of Cymbopogon citratus (Lemongrass)

The search for natural antimicrobial substances to mitigate the deleterious effects of pathogens is on the increase due to the spread of resistance. In the agricultural sector, the current focus is on natural, eco-friendly, and sustainable approaches to improve crop yield. In this study, sixty actinomycetes isolates belonging to 3 genera; Streptomyces, Nocardia, and Micromonospora, obtained from 30 lemon grass rhizosphere samples, were screened for antifungal activity using three common fungi phytopathogens; Fusarium solani, Aspergillus flavus and Alternaria alternata. Preliminary screening involving the in vitro dual culture assay and the agar well diffusion techniques were employed to investigate the inhibitory activities of actinomycetes isolates and the ethyl acetate extract of their metabolites against the phytopathogens. Results obtained revealed that mycelial extensions in the fungi were significantly inhibited, though, to varying extents. Among the 60 actinomycetes isolates screened, 19 (31.37%) demonstrated significant inhibitory activity against at least one of the three test fungi. Out of the 19 isolates, 5(26.3%) suppressed mycelial growth in all three test fungi with percent mycelial inhibitions ranging from 51.63 – 69.29 %. Also, the crude extracts of the metabolites of these five actinomycetes isolates produced mycelial inhibitions ranging from 75.45 - 89.31 %. Analysis of the crude extracts using gas chromatography, revealed the production of five antifungal compounds which include: Benzylaldehyde,2-nitro-diaminomethylidene hydrazine, [1,2,4] triazolo [1,5] pyrimidine -6-carboxylic acid, 1,2, - benzenediol,3,5-bis(1,1-dimethylethyl), Benzo[h] quinolone,2,4-dimethyl-, and 2,4,6-cycloheptatrien-1-one, 3,5, bis-trimethylsilyl-. Therefore, the antifungal capabilities of these actinomycetes isolates make them efficient, natural, and ecologically friendly alternatives in the control of fungal phytopathogens.

Telaah: Pengaruh Variasi Jenis Bahan dan Metode Pengawetan Alami Terhadap Kualitas Telur Ayam

Chicken eggs are one of the food products that are easily contaminated by microorganisms either directly or indirectly. Contamination generally comes from straw where eggs are laid, soil, air and poultry droppings. Eggs stored at room temperature for more than 10-14 days will undergo chemical and microbiological changes which result in a decrease in quality. One of the things that is needed to address this is to preserve egg products so that the products can be stored for a longer time. The main parameters of egg quality can be observed based on the index of egg yolk and egg white, HU value, and pH value. active ingredients contained in the ingredients, conditions and duration of storage, and methods of preservation. Preservation methods can be done by utilizing natural ingredients that contain active compounds. Active compounds that play a role can be tannins, polyphenols, flavonoids which act as natural antimicrobial substances. Generally, these active compounds will inhibit the entry of microorganisms through the pores of the eggs by forming complex compounds so that the metabolism of microorganisms will be disrupted. Keywords: Active Compounds , Damage, Eggs , Natural Ingredients, Preservation .

Effects of the cultivation conditions on antimicrobial activity of Lactiplantibacillus sp. NCL33 isolated from Nem chua

There is an increasing demand from consumers for natural and minimally processed foods. Therefore, developing and producing effective natural antimicrobial substances for food preservation is of great interest. This work aimed to investigate the effect of growth conditions on the maximum activity of antibacterial substances production by Lactiplantibacillus sp. NCL33 from Nem chua, a traditional fermented meat. The results revealed that the antibacterial substances exhibited a broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria. The antibacterial activity of NCL33 was optimized with MRS broth supplemented with 20 g/L glucose. The suitable nitrogen source for antibacterial biosynthesis was yeast extract with a concentration of 25 g/L. Moreover, the inoculated temperature and initial pH significantly influenced the antimicrobial activity. The maximum antimicrobial activity of NCL33 was obtained at 30&amp;deg;C and pH 7,0. &amp;nbsp;

Purification, structure and characterization of the novel antimicrobial lipopeptides produced by Paenibacillus ehimensis HD

Considerable challenges remain in the development and application of natural antimicrobial substances for food preservation to meet food safety needs. In this paper, ehimensins F4, F5, and F6, three antimicrobial peptides produced by Paenibacillus ehimensis HD, were purified by using macroporous adsorption resin and RP-HPLC. The molecular mass of ehimensins F4 and F5 was 1101 Da and that of ehimensin F6 was 1115 Da. LC–MS/MS demonstrated that each ehimensin consisted of fatty acids, 2,4-diaminobutyric acid, and amino acids. Meanwhile, circular dichroism revealed that each ehimensin was mainly composed of random coil and β-sheet structures. The three ehimensins maintained high activities under different conditions because they were stable over a wide range of temperatures and pH and in the presence of protease. Moreover, they exhibited low hemolysis activities and obvious antimicrobial activities against various food pathogenic bacteria and fungi. Soaking the strawberries in 1.0 mg/mL ehimensins for 1 min at room temperature could significantly inhibit fungal growth. And the shelf life of the strawberries was extended from 1 day to 4 days. These results suggested that ehimensins from P. ehimensis HD have great potential for use as biopreservatives to improve food safety.

Construction of nano slow-release systems for antibacterial active substances and its applications: A comprehensive review.

At present, nano-carrier materials with antibacterial activity are of great significance. Due to the widespread resistance of many pathogenic microorganisms, it has seriously threatened human health. The natural antimicrobial substances extracted from fruits and vegetables can significantly improve their stability combined with nano-carrier materials. The resistance of pathogenic microorganisms will be substantially reduced, greatly enhancing the effect of active antimicrobial substances. Nanotechnology has excellent research prospects in the food industry, antibacterial preservation, food additives, food packaging, and other fields. This paper introduces nano-carrier materials and preparation techniques for loading and encapsulating active antibacterial substances in detail by constructing a nano-release system for active antibacterial substances. The antibacterial effect can be achieved by protecting them from adverse external conditions and destroying the membrane of pathogenic microorganisms. The mechanism of the slow release of the bacteriostatic active substance is also described. The mechanism of carrier loading and release is mainly through non-covalent forces between the bacteriostatic active substance and the carrier material, such as hydrogen bonding, π-π stacking, van der Waals forces, electrostatic interactions, etc., as well as the loading and adsorption of the bacteriostatic active substance by the chemical assembly. Finally, its wide application in food and medicine is introduced. It is hoped to provide a theoretical basis and technical support for the efficient utilization and product development of bacteriostatic active substances.