Isolation, Identification, and Screening of Lactic Acid Bacteria with Probiotic Potential in Silage of Different Species of Forage Plants, Cocoa Beans, and Artisanal Salami

Novel food isolates with striking α-glucosidase inhibitory activity and probiotic potential for an antidiabetic role

In the current study, ten lactic acid bacteria (LAB) isolates exhibiting anti-α-glucosidase activity were isolated from fermented food. It is directed at novel supplementary diets to prevent/improve diet-induced carbohydrate metabolism disorders and related chronic diseases. Moreover, to evaluate their safety, functionality, and probiotic potential via in vitro simulated test conditions. From 16s-rRNA sequencing, Pediococcus acidilactici (NKUST 803, 845, 858), Lactobacillus plantarum (NKUST 817, 828, 851), Levilactobacillus brevis (NKUST 816, 855) and Lactobacillus acidophilus (NKUST 803, 863) were identified. The results showed that the isolates possessed anti-pathogenic activity, auto-aggregation ability, hydrophobicity (47.44-96.4%), and gastric acid-resistant activity (79-99.1%), which proved their potential for probiotics in nutraceuticals to render hypoglycemic activity or antidiabetic effects to the host positively. Among tested isolates, L. plantarum 817 and P. acidilactici 858 exhibited maximum α-glucosidase inhibitory (AGI) activity of 35-40%. The heat map clearly showed that L. plantarum 817 exhibited the best AGI activity and probiotic potential, among others. These were studied under various simulated gut conditions and safety tests. However, all isolates possess the potential to be used as probiotics in commercial-scale health applications. Pediococcus sp. possesses notable AGI activity but relatively less colonization potential in the gut hence recommended daily intake for positive health effects.

K. J, Goh KW, Desai SM, H. L. K, Ramu R. Characterization of Lactobacillus spp. as Probiotic and Antidiabetic Potential Isolated from Boza, Traditional Fermented Beverage in Turkey

Boza, a cereal-based beverage popular in southeast Europe, is fortified with probiotics and is believed to positively impact the composition of the gut microflora. This investigation focused on fermented cereal-based beverage boza to identify strains of probiotic Lactobacillus spp. capable of inhibiting carbohydrate-hydrolysing enzymes α-glucosidase (AG) and α-amylase (AA). The isolated bacterial strains underwent a comprehensive assessment, including biochemical, molecular, and probiotic trait analyses such as tolerance survivability, adhesion, safety, and health-promoting attributes. We evaluated the inhibitory potential of the supernatant, cell lysate, and intact cells of Lactobacillus spp. Molecular analysis has revealed that isolates RAMULAB30 and RAMULAB29 exhibit a significant genetic similarity (>97%) to Lacticaseibacillus paracasei and Limosilactobacillus fermentum, respectively. These findings are documented in the NCBI database. They exhibited significant resistance to gastrointestinal and intestinal fluids, also indicating their potential for adhesion. Additionally, the isolates showed a significant antibacterial activity, particularly against Micrococcus luteus. They showed resistance to vancomycin and methicillin antibiotics but were more susceptible to streptomycin and ampicillin. Furthermore, the strains demonstrated antioxidant properties. To ensure their safety, a haemolytic assay was conducted despite their general recognition as safe (GRAS) status. The study primarily aimed to evaluate the inhibitory effects of the extract on enzymes AG and AA. Bacterial isolates demonstrated a significant inhibitory activity against both enzyme AG (32%-67% inhibition) and enzyme AA (18%-46% inhibition) in different forms, including supernatant (CS), lysed extract (CE), and intact cell (IC). These findings underscore the potential of bacterial isolates to inhibit the enzyme activity effectively. Furthermore, the L. fermentum RAMULAB29 and L. paracasei RAMULAB30 strains exhibit remarkable antidiabetic potential. Food products incorporating these strains have promising prospects as nutraceuticals, providing improved health benefits.

A novel Lactiplantibacillus plantarum strain: probiotic properties and optimization of the growth conditions by response surface methodology

The objective of this study is to explore the probiotic properties and optimal growth conditions of Lactiplantibacillus plantarum BG24. L. plantarum BG24 exhibited a remarkable ability to utilize lactose, and to grow under acidic conditions and in the presence of high levels of bile salts. The strain showed the highest antibacterial activity against L. monocytogenes Scott A (zone of inhibition: 26 mm). L. plantarum BG24 was found to be resistant to 8 of the tested 19 antibiotics using the disc diffusion method.and its multiple antibiotic resistance (MAR) index was calculated as 0.421. The adhesion rate to human intestinal epithelial Caco-2 cells was determined as 37.51%. The enzyme profile of L. plantarum BG24 was investigated using API ZYM test kit and the highest enzymatic activities were found for Leucine arylamidase, β-glucosidase, Valine arylamidase, β-galactosidase and N-acetyl-β-glucosaminidase. L. plantarum BG24 strain showed higher microbial growth under static conditions (6.60 OD600) compared to 100 rpm (5.73 OD600) and 200 rpm (5.02 OD600) shaking speed due to its facultative anaerobic characteristic. However, different inoculation rates and glucose addition did not make a statistically significant difference on biomass formation (p > 0.05). The specific growth rate of L. plantarum BG24 was 0.416 h-1, the doubling time was 1.67 h, and the biomass productivity value was 0.14 gL-1 h-1 in the original MRS broth (pH 5.7) while higher values were found as 0.483 h-1, 1.43 h and 0.17 gL-1 h-1, respectively, in MRS broth (pH 6.5) medium enriched with 5 g/L yeast extract. The stirred tank bioreactor was used to optimise the growth of BG24 strain. The process variables was optimized at 0.05 vvm of aeration rate, 479 rpm of agitation speed, 3% of inoculation rate and 18 h of incubation time. The maximum biomass (g/L) production was obtained as 3.84 g/L at the optimized conditions.

Effects of Different Lactic Acid Bacteria in Single or Mixed Form on the Fermentative Parameters and Nutrient Contents of Early Heading Triticale Silage for Livestock

Lactic acid bacteria (LAB) are excellent anaerobic fermenters that produce highly valuable grass-based animal feed containing essential nutrients. In the present study, an ensiling process was used to improve anaerobic fermentation in triticale silage under different moisture conditions with LAB. The triticale was treated with either a single bacterium or combined LAB and then vacuum-sealed. After 180 and 360 days of storage, the silage's fermentation characteristics, microbial changes and nutrient contents were analyzed. The pH of the silage was significantly lower than the control silage. There was a significant difference in the pH values between the silages treated with single or mixed LAB. The LAB treatment led to a substantial increase in lactic acid (LA), a decrease in butyric acid (BA), and marginal levels of acetic acid (AA). The LA content after the mixed LAB treatment was significantly higher than that after the single culture LAB treatment. After single or combined inoculant treatments, the LAB population in the silage increased, while the yeast and mold levels decreased. These findings suggest that the addition of LAB to silage during ensiling could enhance the nutritional quality and reduce unwanted microbial growth. The mixed LAB treatments produced silage with a significantly higher nutritional value than the single LAB treatments.

Probiotic and Safety Evaluation of Twelve Lactic Acid Bacteria as Future Probiotics

The human gut flora is highly diverse. Most lactic acid bacteria (LAB) are widely used as probiotics in human and animal husbandry and have a variety of physiological benefits. This article mainly studied the bacteriostatic ability of LAB against four pathogenic bacteria, gastrointestinal environment tolerance, and adhesion ability to Caco-2 cells. The genome of Lactiplantibacillus plantarum L461 was sequenced and analyzed. The results showed that strains F512, L461, and D469 had the most significant inhibitory effects on Escherichia coli, Salmonella enterica B, Staphylococcus aureus, and Listeria monocytogenes. In addition, strains L461, C502, and P231 showed good tolerance after exposure to simulated gastric fluid for 0-4 h. Strains C502, H781, and L461 showed good tolerance in simulated intestinal fluid. Strains L461 and H781 showed good adhesion to Caco-2 cells. The number of viable bacteria was more than 60. Therefore, we screened L. plantarum L461 from 12 LAB strains through three aspects of evaluation, and conducted whole genome sequencing and analysis. Sequencing results showed that L. plantarum L461 had more defense mechanisms and phage annotation genes than L. plantarum WCFS1. Virulence factor studies showed that L. plantarum L461 has iron absorption system and adhesion-related gene annotation, indicating that L. plantarum L461 has survival advantage in intestinal tract. The predicted results showed that there were eight phages with phage resistance in L. plantarum L461. L. plantarum L461 is sensitive to several antibiotics, notably penicillin and oxacillin. In summary, the results of this study prove that L. plantarum L461 has good prebiotic function and is safe. Therefore, L. plantarum L461 can be safely used as a potential functional probiotic.

Exploration of probiotic attributes in lactic acid bacteria isolated from fermented Theobroma cacao L. fruit using in vitro techniques

Probiotics are known for their health-promoting properties and are recognized as beneficial microorganisms. The current investigation delves into the isolation and comprehensive in vitro characterization of lactic acid bacteria (LAB) obtained from the Indian-origin Theobroma cacao L. Forastero variety to assess their potential as probiotic candidates. Eleven LAB isolates were obtained, and among them, five exhibited classical LAB traits. These five isolates underwent rigorous in vitro characterization to evaluate their suitability as probiotics. The assessments included resilience against acid and bile salts, which are crucial for probiotic viability. Additionally, the isolates were subjected to simulated gastric and pancreatic fluids and lysozyme exposure to assess their survival rates. Auto- aggregation, co-aggregation, hydrophobicity, and exopolysaccharide production were also examined. The inhibitory potential of α-glucosidase, an enzyme related to glucose metabolism, was measured, and antioxidant activity was evaluated using DPPH and ABTS assays. A safety assessment was conducted to confirm the non-pathogenic nature of the isolates. Among the five isolates, CR2 emerged as a standout candidate with maximal bile salt hydrolase activity, phenol resistance, and lysozyme resistance. CR2 and CYF3 exhibited notable survival rates under simulated conditions. The isolates displayed variable degrees of auto-aggregation, co-aggregation, and hydrophobicity. CR2 exhibited the highest exopolysaccharide production (0.66 mg/mL), suggesting diverse applications in the food industry. CR2 also demonstrated the highest inhibition rate against α-glucosidase (56.55%) and substantial antioxidant activity (79.62% DPPH, 83.45% ABTS). Safety assessment confirmed the non- pathogenic nature of the isolates. Molecular characterization identified CR2 as Lactococcus lactis subsp. lactis and CYF3 as Limnosilactobacillus fermentum. Both strains exhibited commendable probiotic and technological attributes, positioning them as promising candidates for functional foods and beyond. This study provides valuable insights into the in vitro characterization of LAB isolated from Indian Theobroma cacao L., highlighting their potential as probiotic candidates with advantageous traits, including survival in hostile conditions, beneficial enzymatic activities, bioactivity, and other essential attributes.

The Impacts of Acidophilic Lactic Acid Bacteria on Food and Human Health: A Review of the Current Knowledge

The need to improve the safety/quality of food and the health of the hosts has resulted in increasing worldwide interest in acidophilic lactic acid bacteria (LAB) for the food, livestock as well as health industries. In addition to the use of acidophilic LAB with probiotic potential for food fermentation and preservation, their application in the natural disposal of acidic wastes polluting the environment is also being investigated. Considering this new benefit that has been assigned to probiotic microorganisms in recent years, the acceleration in efforts to identify new, efficient, promising probiotic acidophilic LAB is not surprising. One of these effots is to determine both the beneficial and harmful compounds synthesized by acidophilic LAB. Moreover, microorganisms are of concern due to their possible hemolytic, DNase, gelatinase and mucinolytic activities, and the presence of virulence/antibiotic genes. Hence, it is argued that acidophilic LAB should be evaluated for these parameters before their use in the health/food/livestock industry. However, this issue has not yet been fully discussed in the literature. Thus, this review pays attention to the less-known aspects of acidophilic LAB and the compounds they release, clarifying critical unanswered questions, and discussing their health benefits and safety.

Interaction between plants and epiphytic lactic acid bacteria that affect plant silage fermentation

Lactic acid bacteria (LAB) have the ability to ferment water-soluble carbohydrates, resulting in the production of significant amounts of lactic acid. When utilized as additives in silage fermentation and feed, they have been shown to enhance the quality of these products. Epiphytic LAB of plants play a major role in the fermentation of silage plants. Plant species in turn affect the community structure of epiphytic LAB. In recent years, an increasing number of studies have suggested that epiphytic LAB are more effective than exogenous LAB when applied to silage. Inoculating silage plants with epiphytic LAB has attracted extensive attention because of the potential to improve the fermentation quality of silages. This review discusses the interaction of epiphytic LAB with plants during silage fermentation and compares the effects of exogenous and epiphytic LAB on plant fermentation. Overall, this review provides insight into the potential benefits of using epiphytic LAB as an inoculant and proposes a theoretical basis for improving silage quality.

Dynamic Development of Viral and Bacterial Diversity during Grass Silage Preservation

Ensilaging is one of the most common feed preservation processes using lactic acid bacteria to stabilize feed and save feed quality. The silage bacterial community is well known but the role of the virome and its relationship with the bacterial community is scarce. In the present study, metagenomics and amplicon sequencing were used to describe the composition of the bacterial and viral community during a 40-day grass silage preservation. During the first two days, we observed a rapid decrease in the pH and a shift in the bacterial and viral composition. The diversity of the dominant virus operational taxonomic units (vOTUs) decreased throughout the preservation. The changes in the bacterial community resembled the predicted putative host of the recovered vOTUs during each sampling time. Only 10% of the total recovered vOTUs clustered with a reference genome. Different antiviral defense mechanisms were found across the recovered metagenome-assembled genomes (MAGs); however, only a history of bacteriophage infection with Lentilactobacillus and Levilactobacillus was observed. In addition, vOTUs harbored potential auxiliary metabolic genes related to carbohydrate metabolism, organic nitrogen, stress tolerance, and transport. Our data suggest that vOTUs are enriched during grass silage preservation, and they could have a role in the establishment of the bacterial community.

Isolation of lectin from Musa acuminata for its antibiofilm potential against Methicillin-resistant Staphylococcus aureus and its synergistic effect with Enterococcus species

Methicillin resistant Staphylococcus aureus (MRSA) is an emerging pathogen posing a considerable burden on the healthcare system due to its involvement in skin and soft tissue infections (SSTIs). Lectins are carbohydrate binding proteins found ubiquitously in animals, plants and microorganisms. Extraction and isolation of proteins from Musa acuminata were performed by using Affinity chromatography with Sephadex G 75 to determine antibiofilm activity against MRSA. Enterococcus strains obtained from dairy products, beans and vegetables were also screened for its potential to inhibit growth and biofilm formation of MRSA by using 96 well microtiter plates. Synergistic effect of cell free supernatant of Enterococcus with proteins from ripe banana were also tested. BanLec was successfully isolated and appeared as 15 KDa band after SDS-PAGE (15%) while multiple bands of unbound protein fractions were observed. The unbound fractions showed inhibition of planktonic cells and biofilm but BanLec exhibited no significant effect. The CFS of Enterococcus faecium (LCM002), Enterococcus lactis (LCM003) and Enterococcus durans (LCM004 and LCM005) displayed antagonistic effects against pathogen. The synergistic effect of CFS from E. lactis (LCM003) and unbound proteins showed inhibition of biofilm and pathogenic growth. This study demonstrates the use of Enterococcus species and plant proteins against pathogens and results suggested that it can inhibit the growth of resistant strains of Staphylococcus aureus and their synergistic effect has opened new ways to tackle emerging resistance. Furthermore, after assessment of Enterococcus as probiotics, this could be used in food industries as well as in treatment of severe skin infections.

Lactic acid bacteria biofilms and their antimicrobial potential against pathogenic microorganisms

The continuous growth of pathogenic microorganisms and associated biofilms poses severe public health challenges, particularly in food and clinical environments. However, these difficulties have enabled scientists to develop novel and safe methods for combating pathogens. The use of biofilms produced by lactic acid bacteria (LAB) against pathogenic bacteria has recently gained popularity. This review provides an in-depth look at LAB biofilms, their distribution, and mechanisms of action against pathogenic bacteria. More importantly, the bioactive substances produced by LAB-forming biofilm may be active against undesirable microorganisms and their products, which is of great interest in improving human health. Therefore, this review implies that a combination of LAB biofilms and other LAB products like bacteriocins could provide viable alternatives to traditional methods of combating pathogenic microorganisms and their biofilms.

Exploring the effect of Lactiplantibacillus plantarum Lac 9-3 with high adhesion on refrigerated shrimp: Adhesion modeling and biopreservation evaluation

Lactic acid bacteria (LAB) have recently become ideal candidates for developing food biopreservatives. Adhesion is critical for LAB to perform biocontrol functions in food processing and preservation. In this study, we innovatively proposed an effective adhesion evaluation model related to the surface properties of LAB to excavate a LAB strain with high adhesion on the surface of shrimp. Then, the biocontrol potential regarding the quality of refrigerated shrimp was explored, especially for protein quality. The screening of highly adherent LAB was performed using 54 LAB strains tolerant to the low temperature (4 °C) and present antimicrobial activity. Based on surface hydrophobicity, autoaggregation, and biofilm formation, a new method for predicting LAB adhesion was established by stepwise multiple linear regression. The most relevant relationship between adhesion and biofilm formation was derived from the model. Lactiplantibacillus plantarum Lac 9-3 stood out for the strongest adhesion on the shrimp surface and the highest antimicrobial activity. The preservation results showed that Lac 9-3 significantly (p < 0.05) retarded the accumulation of total volatile basic nitrogen (TVB-N) and the growth of spoilage bacteria. The damage to the texture properties of shrimp was inhibited. Meanwhile, the degradation of myofibrillar protein was alleviated, including a significant delay (p < 0.05) in sulfhydryl (SH) group reduction, surface hydrophobicity increases, and protein conformation changes. This research optimized the evaluation of the bacteria adhesion potential, providing a new idea for developing biocontrol strategies to extend the commercial life of aquatic products.

Vitality, fermentation, aroma profile, and digestive tolerance of the newly selected Lactiplantibacillus plantarum and Lacticaseibacillus paracasei in fermented apple juice

Background

To enrich the probiotic lactic acid bacteria (LAB) strains and expand the commercialization of new fermented juice products, we have identified two LAB strains with excellent potential in fermenting apple juice from pickles.

Methods

The two strains were morphologically, physiologically, and genetically characterized. The strains' fermentation performance and alterations in volatile aroma components of apple juice and ability to survive in a simulated gastrointestinal environment were evaluated.

Results

Two strains were identified as Lacticaseibacillus paracasei (WFC 414) and Lactiplantibacillus plantarum (WFC 502). The growth of WFC 414 and WFC 502 in apple juice for 48 h reached 8.81 and 9.33 log CFU/mL, respectively. Furthermore, 92% and 95% survival rates were achieved in 2 h simulated gastric juice, and 80.7 and 83.6% survival rates in 4 h simulated intestinal juice. During the fermentation, WFC 414 and WFC 502 reduced the soluble sugars and total polyphenols in apple juice, and consumed malic acid to produce large amounts of lactic acid (3.48 and 5.94 mg/mL). In addition, the esters and aldehydes were reduced, and the production of alcohols, acids and ketones was elevated in the apple juice fermented by both strains.

Conclusion

These results show that WFC 414 and WFC 502 have great potential applications in the fermented fruit juice industry.

Current approaches on the roles of lactic acid bacteria in crop silage

Lactic acid bacteria (LAB) play pivotal roles in the preservation and fermentation of forage crops in spontaneous or inoculated silages. Highlights of silage LAB over the past decades include the discovery of the roles of LAB in silage bacterial communities and metabolism and the exploration of functional properties. The present article reviews published literature on the effects of LAB on the succession, structure, and functions of silage microbial communities involved in fermentation. Furthermore, the utility of functional LAB in silage preparation including feruloyl esterase-producing LAB, antimicrobial LAB, lactic acid bacteria with high antioxidant potential, pesticide-degrading LAB, lactic acid bacteria producing 1,2-propanediol, and low-temperature-tolerant LAB have been described. Compared with conventional LAB, functional LAB produce different effects; specifically, they positively affect animal performance, health, and product quality, among others. In addition, the metabolic profiles of ensiled forages show that plentiful probiotic metabolites with but not limited to antimicrobial, antioxidant, aromatic, and anti-inflammatory properties are observed in silage. Collectively, the current knowledge on the roles of LAB in crop silage indicates there are great opportunities to develop silage not only as a fermented feed but also as a vehicle of delivery of probiotic substances for animal health and welfare in the future.

Optimizing Conditions in the Acid Tolerance Test for Potential Probiotics Using Response Surface Methodology

Acid tolerance is an important feature of probiotic development. It is one of the factors underlying the beneficial effects of probiotics in the intestine. However, the methods used by different researchers to test acid tolerance vary, causing confusion in the interpretation of the results. Therefore, in this study, we determine the optimal conditions for the acid tolerance test using response surface methodology. The factors of pH (2.5 to 3.5), exposure time (1 to 2 h), and pepsin (presence or absence) were used as independent variables, and the survival rates of seven strains (Lacticaseibacillus casei KACC 12413, Lactiplantibacillus plantarum KACC 15357, Limosilactobacillus fermentum KACC 11441, Lactiplantibacillus plantarum WCFS1, Lacticaseibacillus rhamnosus GG, Lactiplantibacillus plantarum KCTC 21024, and Lactiplantibacillus plantarum WiKim 0112) known to have probiotic properties were used as dependent variables. The results of the analysis of variance (ANOVA) indicated that the pH value and exposure time in acidic environments significantly affected the acid tolerance test model, and their interaction also had an effect (P < 0.05). Using the ANOVA results, the condition of the acid tolerance test was optimized with a target of an 85% survival rate for each strain. The optimized conditions of the acid tolerance test were as follows: pH 2.92, exposure time of 1.73 h, and presence of pepsin and pH 3, exposure time of 1.98 h, and absence of pepsin. These results can optimize strain selection with rigorous acid tolerance without confusion by unifying the conditions for the acid tolerance test. IMPORTANCE The acid tolerance test, which is the first step in selecting probiotics, is not standardized and can often cause confusion in the interpretation of results. Thus, in the present study, we optimized the conditions for the acid tolerance test using response surface methodology. These optimized conditions can be used to screen for strains with acid tolerance.

Exopolysaccharide produced by Lactiplantibacillus plantarum RO30 isolated from Romi cheese: characterization, antioxidant and burn healing activity

Microbial exopolysaccharides (EPSs) extracted from lactic acid bacteria (LAB) are generally recognized as safe. They have earned popularity in recent years because of their exceptional biological features. Therefore, the present study main focus was to study EPS-production from probiotic LAB and to investigate their antioxidant and burn wound healing efficacy. Seventeen LAB were isolated from different food samples. All of them showed EPS-producing abilities ranging from 1.75 ± 0.05 to 4.32 ± 0.12 g/l. RO30 isolate (from Romi cheese) was chosen, due to its ability to produce the highest EPS yield (4.23 ± 0.12 g/l). The 16S rDNA sequencing showed it belonged to the Lactiplantibacillus plantarum group and was further identified as L. plantarum RO30 with accession number OL757866. It displayed well in vitro probiotic properties. REPS was extracted and characterized. The existence of COO⁻, OH and amide groups corresponding to typical EPSs was confirmed via FTIR. It was constituted of glucuronic acid, mannose, glucose, and arabinose in a molar ratio of 2.2:0.1:0.5:0.1, respectively. The average molecular weight was 4.96 × 10⁴ g/mol. In vitro antioxidant assays showed that the REPS possesses a DPPH radical scavenging ability of 43.60% at 5 mg/ml, reducing power of 1.108 at 10 mg/ml, and iron chelation activity of 72.49% and 89.78% at 5 mg/ml and 10 mg/ml, respectively. The healing efficacy of REPS on burn wound models in albino Wistar rats showed that REPS at 0.5% (w/w) concentration stimulated the process of healing in burn areas. The results suggested that REPS might be useful as a burn wound healing agent.

Probiotic potential of Lactobacillus isolated from horses and its therapeutic effect on DSS-induced colitis in mice

Inflammatory bowel disease (IBD) is a refractory disease that endangers both humans and animals. In recent times, Lactobacillus have been used to treat animal diseases. It may be a good choice to try to isolate Lactobacillus with probiotic potential to treat IBD. Equine, as a kind of hindgut fermentation animal has rich intestinal microflora, but data regarding this is scarce. The isolation of Lactobacillus with probiotic potential from equine may become a new method for the treatment of IBD. Four isolates of Lactobacillus were isolated from fresh feces of healthy male adult horses and analyzed their biological characteristics. According to the phylogenetic analysis, A2.5 and A7.1 were identified as Pediococcus pentosaceus, A3 as Lactobacillus plantarum, and B8.2 as Weissella cibaria. All four isolates showed tolerance to the environment of acid, bile salt concentration and simulated artificial gastrointestinal fluid. The hydrophobic rate and self-aggregation rate of A3 were close to 100%, and the adhesion rate was 28.85 ± 0.74%. Four isolates were negative in hemolysis test and sensitive to common antibiotics and different isolates had different sensitivity to antibiotics. The four isolates had antibacterial and antioxidant activities which can reflect their probiotic potential. Furthermore, they could regulate the LPS (Lipopolysaccharides) stimulated Caco-2 cells. We chose A3 as the treatment strain to intervene Dextran sulfate sodium salt (DSS)-induced mice. The results showed that compared with DSS group, DSS + A3 group exhibited reduced Disease activity index (DAI), increased colon length, reduced pathological score and regulated cytokine secretion at the level of gene expression. In this study, four isolates of Lactobacillus with probiotic potential were isolated, and Lactobacillus plantarum A3 with reduced ulcerative colitis in mice was screened. It might provide a potential treatment for IBD.

Probiotic and Antioxidant Properties of Lactic Acid Bacteria Isolated from Indigenous Fermented Tea Leaves (Miang) of North Thailand and Promising Application in Synbiotic Formulation

Miang, a traditional fermented tea from Northern Thailand, potentially hosts beneficial probiotic bacteria. A total of 133 isolates of lactic acid bacteria (LAB) isolated from Miang were evaluated for probiotic potential. Among them, 5 strains showed high tolerance to bile and acidic conditions and were selected for further evaluation. All selected strains showed inhibitory activity against human pathogens, including Bacillus cereus, Staphylococcus aureus, and Salmonella ser. Typhimurium. Nucleotide sequences analysis of the 16S rRNA gene revealed that 3 isolates were identified as Lactobacillus pentosus; the remaining were L. plantarum and Pediococcus pentosaceus, respectively. All 5 strains showed a high survival rate of more than 90% when exposed to simulated gastrointestinal conditions and were also susceptible to antibiotics such as erythromycin, tetracycline, and gentamycin, and resistant to vancomycin, streptomycin, and polymycin. In addition, the selected isolates exhibited different degrees of cell surface hydrophobicity (58.3–92.9%) and auto-aggregation (38.9–46.0%). The antioxidant activity reflected in DPPH scavenging activities of viable cells and their cell-free culture supernatants (CFCS) were also found in selected LAB isolates. Moreover, selected LAB isolates showed ability to grow on commercial prebiotics (GOS, FOS or XOS). The preliminary study of spray-drying using cyclodextrin as thermoprotectant suggested that all strains can be designed as a powdered formulation. L. pentosus A14-6 was the best strain, with high tolerance against simulated gastrointestinal conditions, high cell surface hydrophobicity, effective response to tested commercial oligosaccharides, especially XOS, and the highest cell antioxidant properties. L. pentosus A14-6 was therefore targeted for further applications in food and synbiotic applications.

In Vitro Evaluation of Probiotic Properties of Lactobacillus plantarum UBLP40 Isolated from Traditional Indigenous Fermented Food

In this study, traditional indigenous fermented food isolate Lactobacillus plantarum UBLP40 was screened for in vitro probiotic properties, antibiotic susceptibility, hemolytic activity, production of lactic acid, hydrogen peroxide, bile salt hydrolase and phytase, and antioxidative activity. Results showed that Lact. plantarum UBLP40 can survive simulated gastrointestinal conditions, adhere to mucin, possess a hydrophobic cell surface, ability to auto-aggregation, and possessed antimicrobial activity against Micrococcus luteus MTCC 106, methicillin-resistant Staphylococcus aureus subsp. aureus ATCC® BAA-1720, Pseudomonas aeruginosa MTCC 1688, and Escherichia coli MTCC 1687. Lact. plantarum UBLP40 produced 48.59 U/mg phytase and 1.78 ± 0.01 gm % lactic acid and showed the ability to produce hydrogen peroxide and bile salt hydrolase. Moreover, the usual antibiotic susceptible profile and non-hemolytic activity indicated the safety of the strain. The intracellular extract of UBLP40 showed 13.8 ± 1.4% (equivalent to ~8 µM butylated hydroxytoluene) α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, reducing activity equivalent to 1 µg L-cysteine, Fe²⁺ chelation equivalent to 5 µM ethylenediaminetetraacetic acid, and exhibited 17.73 ± 4.40 µM glutathione per gram of protein. In conclusion, this study demonstrates that Lact. plantarum UBLP40 is a potential probiotic candidate.

Potential of Lactic Acid Bacteria Isolated From Different Forages as Silage Inoculants for Improving Fermentation Quality and Aerobic Stability

We aimed at isolating lactic acid bacteria (LAB) from different plant materials to study their crossed-fermentation capacity in silos and to find strains able to confer enhanced aerobic stability to silage. A total of 129 LAB isolates were obtained from lucerne (alfalfa), maize, sorghum, ryegrass, rice, barley, canola, Gatton panic, Melilotus albus, soy, white clover, wheat, sunflower, oat, and moha. Four Lactiplantibacillus plantarum subsp. plantarum strains (isolated from oat, lucerne, sorghum, or maize) were selected for their growth capacity. Identity (16S sequencing) and diversity (RAPD-PCR) were confirmed. Fermentative capacity (inoculated at 10⁴, 10⁵, 10⁶, 10⁷ CFU/g) was studied in maize silage and their cross-fermentation capacity was assessed in oat, lucerne, sorghum, and maize. Heterofermentative strains with the highest acetic acid production capacity conferred higher aerobic stability to maize silages. Regardless the source of isolation, L. plantarum strains, inoculated at a rate of 10⁶ CFU/g, were effective to produce silage from different plant materials. From more than 100 isolates obtained, the application of a succession of experiments allowed us to narrow down the number of potential candidates of silage inoculants to two strains. Based on the studies made, L. plantarum LpM15 and Limosilactobacillus fermentum LfM1 showed potential to be used as inoculants, however further studies are needed to determine their performance when inoculated together. The former because it positively influenced different quality parameters in oat, lucerne, sorghum, and maize silage, and the latter because of its capacity to confer enhanced aerobic stability to maize silage. The rest of the strains constitute a valuable collection of autochthonous strains that will be further studied in the future for new applications in animal or human foods.