Characterization Of Lactic Acid Bacteria Research Articles

Screening and characterization of lactic acid bacteria with antibacterial effect against heat-resistant spore outgrowth of Bacillus sporothermodurans

This study is the first to screen of lactic acid bacteria strains with antimicrobial effect against spore outgrowth of Bacillus sporothermodurans and characterize their technological properties. Eighty strains were isolated from Tunisia raw milk but only 8 isolates were selected based on their antagonistic activity against germinated spores of B. sporothermodurans and nine pathogenic bacteria. Phenotypic and genotypic characterization allowed us to distinguish three different species, namely Lactiplantibacillus plantarum, Levilactobacillus brevis and Lactococcus lactis. The lactic acid strains able to produce protease and lipase enzymes. The important antagonistic activity was observed in presence of L. lactis TLAB6 strain which produced a bacteriocin and lactic acid. The bacteriocin produced by the L. lactis TLAB6 is heat stable and resistant to trypsin. The results suggest that the selected LAB with antibacterial activity against germinated spore and technological properties may be used to preserve the food and formulate of bioactive functional foods.

Assessment and Characterization of Lactic Acid Bacteria Isolated from Fermented African oil Bean Seed (Pentaclethra macrophylla) for Probiotic Application

Among the bacteria in fermented foods, lactic acid bacteria play a pivotal role and its main function is to convert carbohydrates and other related raw materials into lactic acid (organic acid). Therefore, the aim of this research was to assess and use lactic acid bacteria isolates obtained from fermented African oil bean seeds as probiotics. Lactic acid bacteria were isolated using MRS agar and screened for organic acid production and the ability to tolerate some environmental conditions such as temperature, pH, and osmotic pressure. The use of the isolates as probiotics was investigated by screening and determining the antimicrobial inhibitory zone diameter of the isolates obtained against the indicator microorganisms such as Staphylococcus aureus, Bacillus cereus, Escherichia coli and Listeria monocytogenes. Results show that isolate2, isolate3, isolate5, isolate6, isolate7 and isolate8 were able to produce organic acid. Out of the six bacterial isolates tested for antimicrobial activities against the indicator microorganisms, isolate2, isolate3, isolate6 and isolate8 were able to show antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Listeria monocytogenes using different dilutions (10- 1 to 10- 3) of the isolates. The isolates were able to grow at temperatures of 37oCand 45oC; pH of 2.5, 3.0, 3.5 and 4.0; finally the osmotic pressure of 1.0, 1.5, 2.5 and 5.0 % w/v NaCl. The isolates were identified as Lactobacillus species and can be used as probiotics.

In vitro characterization of lactic acid bacteria from Indian fermented rice for probiotic applications

AimTo investigate probiotic attributes of lactic acid bacteria (LAB) isolated from under-explored Indian fermented rice for potential application in consumer health and functional product development. Methods and resultsThe isolates endured conditions resembling gastric stress, including pH (3), bile salt (4%), NaCl (6%), and phenol (0.6%). The selected isolates were identified as L. fermentum and L. plantarum strains by 16 S rRNA sequencing. In a simulated gastrointestinal tract (GIT), isolate SR1 outperformed other cultures in terms of viability. Auto-aggregation, and mucin adhesion abilities were tested for colonization potential. In which, compared to other isolates, MCR1 showed greater mucin adherence. SR1 and MCR1 showed higher percentages of auto-aggregation than GG. The auto-aggregation ranged from 9% to 88%., the levels significantly increase after 24 h incubation. The lower Salt aggregation Test (SAT) values indicated efficient hydrophobicity necessary for persistence in GIT and competitive inhibition to pathogens. All the isolates displayed considerably higher galactosidase activity than GG, isolate FCR2 expressed the highest, up to 613±0.92 Miller’s unit/ml activity. The probiotic candidates displayed broad spectrum antimicrobial activity against food-spoilage fungi and entero-pathogens. The study of safety aspects such as hemolytic, DNase activity, antibiotic susceptibility confirmed unavailability of any virulent factor. ConclusionThe isolates developed substantial galactosidase activity and significant broad-spectrum antibacterial activity. These characteristics make isolates an effective commercial option for β-galactosidase production in the food sector to create low-lactose or lactose-free products. Overall, the isolates' capacity for survival, colonization, and other useful traits may be of commercial relevance. Additionally, isolates can be researched for the production of antibacterial agents and in vivo studies for development of future functional food products. Moreover, these findings lay a robust groundwork for future exploration in probiotics, functional foods and nutraceuticals, while also shedding light on the mechanisms underlying the health benefits of the specified traditional food source. SignificanceThis investigation uncovered potential probiotic LAB of Indian fermented rice origin. By doing so, it expands our understanding of LAB diversity and presents promising candidates for applications in gut health improvement, functional food development, and exploration of natural antibacterial solutions.

Antimicrobial Activity, Genetic Relatedness, and Safety Assessment of Potential Probiotic Lactic Acid Bacteria Isolated from a Rearing Tank of Rotifers (Brachionus plicatilis) Used as Live Feed in Fish Larviculture.

Aquaculture is a rapidly expanding agri-food industry that faces substantial economic losses due to infectious disease outbreaks, such as bacterial infections. These outbreaks cause disruptions and high mortalities at various stages of the rearing process, especially in the larval stages. Probiotic bacteria are emerging as promising and sustainable alternative or complementary strategies to vaccination and the use of antibiotics in aquaculture. In this study, potential probiotic candidates for larviculture were isolated from a rotifer-rearing tank used as the first live feed for turbot larvae. Two Lacticaseibacillus paracasei and two Lactiplantibacillus plantarum isolates were selected for further characterization due to their wide and strong antimicrobial activity against several ichthyopathogens, both Gram-positive and Gram-negative. An extensive in vitro safety assessment of these four isolates revealed the absence of harmful traits, such as acquired antimicrobial resistance and other virulence factors (i.e., hemolytic and gelatinase activities, bile salt deconjugation, and mucin degradation, as well as PCR detection of biogenic amine production). Moreover, Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) analyses unveiled their genetic relatedness, revealing two divergent clusters within each species. To our knowledge, this work reports for the first time the isolation and characterization of Lactic Acid Bacteria (LAB) with potential use as probiotics in aquaculture from rotifer-rearing tanks, which have the potential to optimize turbot larviculture and to introduce novel microbial management approaches for a sustainable aquaculture.

Genotypic and Phenotypic Characteristics of Lactic Acid Bacteria Associated with Forage Plants in the Native Grassland of Western Inner Mongolia and Their Application for Alfalfa Silage Fermentation.

This study was conducted to investigate the genotypic and phenotypic characteristics of lactic acid bacteria (LAB) associated with forage plants in the native grassland of western Inner Mongolia and to evaluate their effects on alfalfa silage fermentation. Forage plants and their spontaneous fermentation silages were analysed using culture-based techniques for LAB isolation; the phenotypic properties and 16S rDNA and pheS or rpoA gene sequences of the isolates were evaluated; alfalfa was ensiled with four additive combinations: Lactiplantibacillus plantarum subsp. plantarum (GI19), Lact. plantarum subsp. plantarum and Pediococcus pentosaceus (GI19+GI51), GI19 and 20 g/kg fresh matter of sucrose (GI19+S), and GI19+GI51+S, for 60 d. A total of 73 strains belonging to 16 species were isolated. All isolates grew at 5-45 °C and in 3.0% NaCl, and most of them grew in 6.5% NaCl. Enterococcus faecalis and Lact. plantarum were 26.03% and 17.81% of the total isolates, respectively. All additives improved the silage quality, while GI19+S was more effective for alfalfa ensiling with a higher lactic acid content and lower pH, undesirable microorganism counts, and acetic acid and NH3-N contents than remnant additives. In conclusion, the LAB species were diverse, and most of them possessed good cryotolerance and osmotolerance; GI19+S was the optimal inoculant for alfalfa fermentation improvement.

Characterization of lactic acid bacteria isolated from the gastrointestinal tract of scaptotrigona mexicana and scaptotrigona pectoralis stingless bees

Stingless bees play an essential role as pollinators and have economic and cultural importance for their honey production. In the last decades, there has been a decrease in their populations by multiple factors. Stingless bees engage in symbiotic relationships with many microorganisms, some of which benefit the host nutritionally and protect them from natural enemies. Lactic acid bacteria benefit the host, but their probiotic ability depends on their antimicrobial capacity. This study included isolating and characterizing eight strains of lactic acid bacteria from the gastrointestinal tracts of stingless bees (Scaptotrigona mexicana and Scaptotrigona pectoralis). The bacterial phenotypic profile and antimicrobial activity, in vitro, against the pathogen Paenibacillus larvae and other common pathogens of the isolated bacteria, were also investigated. It was found that Weisella sp, Fructobacillus tropaeoli, Fructobacillus fructosus, and Fructobacillus pseudoficulneus showed probiotic potential.

Isolation and Potential Probiotic Characterization of Lactic Acid Bacteria from an Ethnic Fermented Beverage having Antibacterial Activity against Human Pathogen Entamoeba histolytica

Isolation and Potential Probiotic Characterization of Lactic Acid Bacteria from an Ethnic Fermented Beverage having Antibacterial Activity against Human Pathogen Entamoeba histolytica

Isolation and Characterization of Lactic Acid Bacteria From Sago Wastewater As Antibacterial

Background: Foodborne diseases are infections of the gastrointestinal tract caused by food containing microbiological agents and usually, these infections affect groups of individuals who have low immune systems. Lactic acid bacteria (LAB)are bacillus-shaped Gram-positive bacteria that work by inhibiting pathogenic bacteria that cause foodborne diseases. Maluku is a region in Indonesia rich in sago production. Sago ihur (Metroxylon sylvestre) and tuni (Metroxylon rumphii) are types of sago commonly found in Maluku. Sago is rich in carbohydrates and therefore has the opportunity to produce LAB. This study aimed to isolate and characterize LAB from sago wastewater was a laboratory experimental research with descriptive method using primary data. Methods: Bacterial isolation was carried out using a selective media. Characterization carried out by macroscopicly characterization by observing shape, margin, elevation, pigmentation, appearance, optical properties, and texture. Microscopic characterization was performed using Gram and spore staining. Results: The results of this study showed that five bacterial isolates (I1, I2, T3, T4, and I5) were successfully isolated in a round shape, flat edges, yellowish white color (not pigmented), shiny appearance, and mucoid texture, but isolate T3 showed a raised elevation and translucent to light (transparent), while for other isolates it was convex and translucent, and non-spore forming gram positive. Conclusion: Antibacterial tests against S. aureus and E. coli showed no inhibition zones. LAB isolates from sago wastewater showed no significant antibacterial effect

Isolation Identification and Molecular Characterization of Lactic Acid Bacteria From Raw Milk Samples Collected from Erzurum Region

Due to its high-water content, milk is an important source of different microbial contents, especially lactic acid bacteria. The aim of this study is to isolate and identify lactic acid bacteria from raw milk samples collected from Erzurum and its surroundings, and to introduce possible new species, or genera, to the taxonomy. For this purpose, DNAs of pure bacterial cultures obtained from 50 raw milk samples collected from producers in Erzurum and its districts were isolated, isolates that differed from each other were selected by rep-PCR, and 11 different species and subspecies [Corynebacterium casei, Enterococcus italicus, E. durans, Lactococcus lactis, Lactococcos lactis subsp. lactis, Lactococcos lactis subsp. hordniae, Lactobacillus paracasei, Leuconostoc lactis, Staphylococcus succinis, Streptococcus parauberis ve S. uberis] in raw milk samples by 16S rRNA sequence analysis. It was concluded that the (GTG)5-PCR method was more successful than BOX-PCR in the identification of lactic acid bacteria isolated from raw milk samples at a species and subspecies level, and the isolate coded TS10, which was 98% similar Streptococcus uberis, may be a new species and should be re-examined with advanced diagnostic techniques.

Molecular identification and probiotic potential characterization of lactic acid bacteria isolated from the pigs with superior immune responses.

Lactic acid bacteria (LAB) belong to a significant group of probiotic bacteria that provide hosts with considerable health benefits. Our previous study showed that pigs with abundant LAB had more robust immune responses in a vaccination experiment. In this study, 52 isolate strains were isolated from the pigs with superior immune responses. Out of these, 14 strains with higher antibacterial efficacy were chosen. We then assessed the probiotic features of the 14 LAB strains, including such as autoaggregation, coaggregation, acid resistance, bile salt resistance, and adhesion capability, as well as safety aspects such as antibiotic resistance, hemolytic activity, and the presence or absence of virulence factors. We also compared these properties with those of an opportunistic pathogen EB1 and two commercial probiotics (cLA and cLP). The results showed that most LAB isolates exhibited higher abilities of aggregation, acid and bile salt resistance, adhesion, and antibacterial activity than the two commercial probiotics. Out of the 14 strains, only LS1 and LS9 carried virulence genes and none had hemolytic activity. We selected three LAB strains (LA6, LR6 and LJ1) with superior probiotic properties and LS9 with a virulence gene for testing their safety in vivo. Strains EB1, cLA and cLP were also included as control bacteria. The results demonstrated that mice treated LAB did not exhibit any adverse effects on weight gain, organ index, blood immune cells, and ileum morphology, except for those treated with LS9 and EB1. Moreover, the antimicrobial effect of LR6 and LA6 strains was examined in vivo. The results indicated that these strains could mitigate the inflammatory response, reduce bacterial translocation, and alleviate liver, spleen, and ileum injury caused by Salmonella typhimurium infection. In addition, the LR6 treatment group showed better outcomes than the LA6 treatment group; treatment with LR6 substantially reduced the mortality rate in mice. The study results provide evidence of the probiotic properties of the LAB isolates, in particular LR6, and suggest that oral administration of LR6 could have valuable health-promoting benefits.

Characterization and technological functions of different lactic acid bacteria from traditionally produced Kırklareli white brined cheese during the ripening period.

In the present study, the evolution of the physicochemical and microbiological characteristics of lactic acid bacteria (LAB) in traditional Kırklareli white brined cheese collected from 14 different cheese manufacturing facilities were investigated on different days of the 90-day ripening period. The obtained LAB within the species Lactococcus (Lc.) lactis, Latilactobacillus (Lt.) curvatus, Lactobacillus (Lb.) casei and Lb. plantarum, Enterococcus (E.) durans, E. faecium, E. faecalis, Streptococcus macedonicus, and Weissella paramesenteroides were characterized in terms of their influence on technological properties and their potential as starter cultures for traditional white brined cheese production. The results of the microbiological and physicochemical investigations showed that a few selected isolates of Lc. lactis, Lb. casei, and Lb. plantarum had certain functions as starter germs. Moderate acidification capacity, antibacterial activity and proteolytic activity, which are characteristic of their use as starter lactic acid bacteria, were found. Importantly, antibiotic resistance among selected Lc. lactis, Lb. casei, and Lb. plantarum isolates was extremely low, whereas some of these isolates demonstrated antibacterial activity against major foodborne pathogenic bacteria. Based on the results obtained in this study, selected Lc. and Lb. isolates can also be considered as starter culture in traditional cheese production.

Characterization of Lactic Acid Bacteria (LAB) Isolated from Homemade Fermented Kimchi in Bangladesh

The purpose of this present study was to explore lactic acid bacteria (LAB) from homemade kimchi. Traditionally, kimchi was made in this study at home using fresh vegetables such as cabbage, carrots, radish, green onion leaf, red pepper, garlic, ginger, salt and rice flour, and fermented for seven days. LAB were isolated using selective media and identified by macroscopic and microscopic morphological analysis and short biochemical tests such as catalase, oxidase and Kliger's iron agar (KIA) test. Probiotic potential of LAB was investigated by acid, salt, temperature tolerance and sugar including glucose, fructose, sucrose, xylose and lactose fermentation test. Four distinct single colonies were isolated from four different kimchi preparations. All isolated bacteria were identified as lactic acid bacteria and found gram positive, non-spore forming, survive in both aerobic and anaerobic condition, catalase and oxidase negative. Isolated LAB survive in both highly acidic (pH 2) and alkaline (pH 8) medium, up to 4% NaCl concentrations and at temperatures ranging from 4°C to 55°C. The isolated LAB have also ability to ferment sugars. These findings reveal that isolated LAB found suitable to survive in the environment of human gastrointestinal tract and have probiotic potential. Bangladesh Pharmaceutical Journal 27(1): 103-109, 2024 (January)

Assessment of Potential Probiotic Properties and Biotechnological Activities of Lactobacillus Strains Isolated from Traditional Algerian Fermented Wheat ELHAMOUM

Background: The objective of the current study was to explore the in vitro probiotic and technological characteristics of lactic acid bacteria (LAB) isolated from Algerian fermented wheat. Methods: Three LAB strains were selected and identified using 16S rRNA gene sequencing, in vitro assessments of probiotic properties included resistance to simulated gastric and intestinal conditions, auto-aggregation and antimicrobial susceptibility against common pathogens. Furthermore, the strains were evaluated for their biotechnological properties. Results: The results of 16S rRNA gene sequencing showed that two of them were Levilactobacillus brevis (LAn91 and LAn110) and LAn12a was Lactiplantibacillus pentosus. The tolerance of all strains to gastric acid and bile salts was more than 90%; they showed a high auto-aggregation capacity and a variable antagonistic property against pathogenic strains. Strain LAn12a presented the best biotechnological characteristics (proteolytic, acidifying and lactose hydrolysis), while the LAn91 and LAn110 strains were not able to acidify milk. All the strains exhibited a survival count in fermented milk exceeding 7 log CFU/ml during storage at 4°C on day 21, which surpasses the requirement of 6 log CFU/ml to provide health benefits. These bacteria can also be employed for the creation of functional foods and to validate their suitability as probiotic starter cultures.

Screening and characterization of lactic acid bacteria and fermentation of gamma-aminobutyric acid-enriched bamboo shoots.

In order to produce fermented bamboo shoots with functional properties, two strains of lactic acid bacteria were selected for inoculation and fermentation. One strain, Lactiplantibacillus plantarum R1, exhibited prominent potential probiotic properties (including gastrointestinal condition tolerance, adhesion ability, antimicrobial ability, and antibiotic resistance), while the other, Levilactobacillus brevis R2, demonstrated the capability of high γ-aminobutyric acid (GABA) production (913.99 ± 14.2 mg/L). The synergistic inoculation of both strains during bamboo shoot fermentation led to a remarkable increase in GABA content (382.31 ± 12.17 mg/kg), surpassing that of naturally fermented bamboo shoots by more than 4.5 times and outperforming mono-inoculated fermentation. Simultaneously, the nitrite content was maintained at a safe level (5.96 ± 1.81 mg/kg). Besides, inoculated fermented bamboo shoots exhibited an increased crude fiber content (16.58 ± 0.04 g/100 g) and reduced fat content (0.39 ± 0.02 g/100 g). Sensory evaluation results indicated a high overall acceptability for the synergistically inoculated fermented bamboo shoots. This study may provide a strategy for the safe and rapid fermentation of bamboo shoots and lay the groundwork for the development of functional vegetable products enriched with GABA.

Isolation and Characterization of Lactic Acid Bacteria from Rice Washing Water Waste

Rice washing water is still considered as household waste because its benefits for plants are not widely known. Rice washing water is obtained from water that is washed many times before cooking which is rich in carbohydrate content in the form of starch and glucose and vitamins. Lactic acid bacteria (LAB) require sugar or carbohydrates from rice washing water which is used as food to support metabolic activity and microbial cell proliferation. LAB is also included in a large group of microorganisms that physiologically produce lactic acid as the main metabolic product. LAB are classified as good bacteria so they are widely used as food processing products, especially those related to human digestion. The use of lactic acid bacteria in the agricultural sector is still very minimal, especially as a biodecomposer, even though LAB has the ability to produce cellulase enzymes which are very important in the breakdown of lignin in organic matter. This study aims to determine the presence of lactic acid bacteria in rice washing water fermentation. Isolation of lactic acid bacteria using pour plate method with MRSA (de Man Rogosa Sharpe Agar) media. Lactic acid bacteria isolates obtained were then characterized morphologically, physically, and biochemically. The results of isolation and characterization obtained four isolates with the codes AL-01, AL-02, AL-03, and AL-04. Four LAB isolates showed gram-positive, catalase-positive, non-motile, non-H2S, and IAA-positive results.

Phenotypic and molecular differentiation of lactic acid bacteria in fonio millet ogi fermentation and their potential as starter cultures

This study focused on the phenotypic and 16S rRNA characterization of lactic acid bacteria (LAB) isolated from spontaneously fermented fonio ogi and evaluation of their starter cultures potentials. The isolates were screened for biochemical characteristics, acidification, organic acid production and growth kinetics. Phenotypically, LABs (n = 28) were identified to be inclusive of Lactiplantibacillus plantarum, Lactiplantibacillus pentosus, Limosilactobacillus fermentum and Pediococcus species. However, genotypic typing revealed the strains as Lactiplantibacillus plantarum, Levilactobacillus brevis, and Pediococcus pentosaceus well as presence of non lactobacillus strains. Suitability for starter cultures revealed higher acidification and organic acid production for strains of Lactiplantibacillus plantarum and Pediococcus pentosaceus to between 3.20–3.65 (pH); 4.67- 6.67 total titratable acidity (TTA); 46.4 − 57.4 mg/g (lactic acid), 0.27–0.36 h (maximum specific growth rate). The selected LABs were shown to be strain specific and strains with rapid rate of acidification, high organic acid production and low pH exhibited significant potential for starter culture.

Isolation and characterization of lactic acid bacteria producing a potent anti-listerial bacteriocin-like inhibitory substance (BLIS) from chhurpi, a fermented milk product.

Nowadays, the bacteriocin industries have seen significant growth, supplanting chemical preservatives in its ability to improve the shelf-life and safety of food. The increasing customer desire to use natural preservatives has fueled advancing bacteriocin research. The objective of this study was to identify lactic acid bacteria (LAB) that produce bacteriocin-like inhibitory substance (BLIS) and have strong anti-listerial activity. We have identified and analyzed a LAB obtained from chhurpi samples, a popular milk-derived product in the Himalayan regions of India and Nepal. The strain was studied and identified based on its morphological, biochemical, and physiological characteristics. Furthermore, the molecular 16s-rDNA analysis suggests that the strain was Lactococcus sp. RGUAM1 (98.2% similar to Lactococcus lactis subsp. hordniae NBRC 100931T). The isolated strain can produce a potent BLIS, which has shown efficacy against three gram-positive bacteria responsible for food spoilage, such as Listeria monocytogenes (MTCC 657), Staphylococcus aureus subsp. aureus (MTCC 87), Lactobacillus plantarum (MTCC 1407), Lactobacillus paraplantarum (MTCC 12904). The scanning electron microscope (SEM) image illustrates that the crude cell-free supernatant (CFS) disrupts the cell envelope, leading to the release of cellular contents and the clustering of cells. In addition, this BLIS can easily withstand a wide range of pH (2-12), temperature (up to 100°C for 15min), bile salt (0.3% W/V), salinity (4% W/V), and enzyme activity of 1600AU/ml against Listeria monocytogenes. Our research offers a robust framework and valuable insights into bio-preservation and its potential applications in diverse food products.

A circular economy approach: A new formulation based on a lemon peel medium activated with lactobacilli for sustainable control of post-harvest fungal rots in fresh citrus fruit

The aim of the study was to develop an effective bio-formulation for preventing post-harvest fungal rots in fresh citrus fruit through a multi-step process that includes isolation and characterization of lactic acid bacteria (LABs) from citrus fruit peel, selection of LAB strains with high antifungal activity, chemical characterization of cell free supernatants (CFS), formulation of a lemon peel powdery-based medium (LM) activated with LAB fermentates, chemical characterization of fermented LM, and evaluation of the efficacy of the new bio-formulation against blue mold. Thirteen LABs were recovered from the rind of citrus fruit and identified by the peptide mass fingerprinting method. The antifungal activity of LABs, isolated from citrus fruit, as well as cell free supernatants (CFSs), obtained from their liquid cultures, was tested against diverse plant pathogenic fungi and oomycetes, using the dual-culture overlay and the diffusion agar assays, respectively. Two isolates designated as N3B2 and M2B2, both identified as Lactiplantibacillus plantarum, were selected among the others for their relevant antifungal activity. Both isolates showed a broad spectrum antagonistic activity comprising also major postharvest pathogens of citrus fruit, such as Penicillium digitatum and P. italicum, the causal agents of green and blue moulds, respectively, Alternaria alternata, Colletotrichum gloeosporioides, C. karsti, Phytophthora citrophthora and Ph. nicotianae. The N3B2 and M2B2 isolates were used as starter cultures to ferment a lemon peel powder medium enriched with a nutrient water solution (LM). The two formulations obtained by fermenting LM with the N3B2 and M2B2 isolates showed a strong in vitro inhibitory activity on the same broad range of pathogens used in the preliminary screening of LABs. Moreover, the two LM-based formulations reduced the severity of blue mold infection and inhibited the sporulation of P. italicum on artificially inoculated lemon fruit. The chemical analysis of LM-based bioformulations revealed their antifungal activity was very probably due to the LAB-derived acidic components, including lactic, acetic, DL-3-phenyllactic, 3-4-dihydroxyhydrocinnamic, salicylic acid vanillic acids. These innovative LM-based bioformulations activated with LAB-derived antifungal compounds will be exploited as edible and biodegradable fruit coatings to prolong the shelf-life and prevent post-harvest rots of fresh citrus fruit.

Biomolecular Characterization of Lactic Acid Bacteria (Lactobacilli and Cocci) Isolated from Nonnonkoumou, a Artisanal Milk Curd in Daloa, Côte D’ivoire

Nonnonkoumou is an artisanal sour milk consumed in Côte d'Ivoire, particularly in the town of Daloa. Its production is carried out under uncontrolled conditions and uses a variety of lactic acid bacteria. The main objective of this study was to characterize the cocci and lactobacilli present in the nonnonkoumou. The cocci had the highest loads going from 8.31 ± 0.14 log CFU / mL to 6.76 ± 0.01 log CFU / mL compared to the lactobacilli which had loads between 6.12 ± 0.30 log CFU / mL and 4.35 ± 0.42 log CFU / ml. This preponderance of cocci in all the nonnonkoumou samples taken in comparison to bacilli have been shown through the cocci / bacilli ratio which varied from 1.9 to 1.22. PCR followed by Amplified Ribosomal DNA Restriction Analysis (ARDRA) after enzymatic digestion with Hae III and Hinf I have revealed 4 Hinf I profiles and 3 Hae III for lactobacilli and 2 Hae III profiles and 4 Hinf I profiles for cocci. This technique has revealed 4 species of lactobacilli isolated from nonnonkoumou which are Lactobacillus reuteri, Lactobacillus paracasei, Lactobacillus plantarum and Fructobacillus durionis and 6 groups of cocci corresponding to 6 species. The species identified during this study made it possible to understand their technological role and their contribution to the health quality of nonnonkoumou.

Characteristics of Lactic Acid Bacteria as Potential Probiotic Starters and Their Effects on the Quality of Fermented Sausages.

The aim of this study was to explore the potential of commercial lactic acid bacteria (LAB) as probiotic starters in fermented sausages. We initially investigated the growth activity, acid production capability, and tolerance to fermentation conditions of Lactobacillus sakei, Lactiplantibacillus plantarum, and Pediococcus pentosaceus. All three LAB strains proved viable as starters for fermented sausages. Subsequently, we explored their potential as probiotics based on their antibacterial and antioxidant capabilities. L. plantarum exhibited stronger inhibition against Escherichia coli and Staphylococcus aureus. All three strains displayed antioxidant abilities, with cell-free supernatants showing a higher antioxidant activity compared to intact cells and cell-free extracts. Moreover, the activities of superoxide dismutase, glutathione peroxidase, and catalase were stronger in the cell-free supernatant, cell-free extract, and intact cell, respectively. Finally, we individually and collectively inoculated these three LAB strains into sausages to investigate their impact on quality during the fermentation process. External starters significantly reduced pH, thiobarbituric acid reactive substances, and sodium nitrite levels. The improvements in color and texture had positive effects, with the L. plantarum inoculation achieving higher sensory scores. Overall, all three LAB strains show promise as probiotic fermentation starters in sausage production.