Probiotic and Triticale Silage Fermentation Potential of Pediococcus pentosaceus and Lactobacillus brevis and Their Impacts on Pathogenic Bacteria

Antibacterial and antibiofilm activity of human gut lactic acid bacteria

The present study focused on the antibacterial and antibiofilm activity of novel lactic acid bacterial (LAB) strains isolated from the healthy human volunteers of different age groups and their consortium (LABCON), against the enteropathogenic bacteria. From the study, methanolic extract of LAB isolates and their consortia were found to have promising antibacterial activity and antibiofilm activity against Escherichia coli (ATCC 35218) and Staphylococcus aureus (ATCC 25923). The antimicrobial compounds including the DL-3 phenyllactic acid, DL-p-hydroxyphenyllactic acid, and Succinic acid produced by the LAB could be considered to inhibit the growth and biofilm formation by E. coli (ATCC 35218) and S. aureus (ATCC 25923). Detailed insight into the antibiofilm activity could also be demonstrated by Confocal Raman microscopy attached with AFM and Fluorescent microscope. From the results of the study, the consortium LABCON was superior in antimicrobial and antibiofilm activity and can be considered to have promising application in infection control.

Changes in microbial dynamics and fermentation characteristics of alfalfa silage: A potent approach to mitigate greenhouse gas emission through high-quality forage silage

Feeding ruminants with high-quality forage can enhance digestibility and reduce methane production. Development of high-quality silage from leguminous plants with lactic acid bacteria can improve digestibility and it mitigate the greenhouse gas emissions. In this study, we developed a high-quality alfalfa silage with improved fermentation index and microbial dynamics using Levilactobacillus brevis-KCC-44 at low or high moisture (LM/HM) conditions and preserved it for 75 or 150 days. Alfalfa fermentation with L. brevis enhances acidification and fermentation characteristics primarily due to the dominance of lactic acid bacteria (LAB) L. brevis (>95%) compared to alfalfa fermented with epiphytic LAB. The inoculant L. brevis improved the anaerobic fermentation indexes resulting in a higher level of lactic acid in both high (10.0 ± 0.12 & 8.90 ± 0.31%DM) and low moisture (0.55 ± 0.08 & 0.39 ±0.0 %DM) in 75 and 150 days respectively, compared to control silage. In addition, the marginal amount of acetic acid (range from 0.23 ± 0.07 to 2.04 ± 0.27 %DM) and a reduced level of butyric acid (range between 0.03 ± 0.0 to 0.13± 02 %DM) was noted in silage treated with LAB than the control. The LAB count and abundance of Levilactobacillus were higher in alfalfa silage fermented with L. brevis. Microbial richness and diversity were reduced in alfalfa silage treated with L. brevis which prompted lactic acid production at a higher level even for a prolonged period of time. Therefore, this L. brevis is an effective inoculant for producing high-quality alfalfa silage since it improves fermentation indexes and provides reproducible ensiling properties.

μMET: A Novel Reusable Microfluidic Chip for Precision Microbial Enumeration Tests

This work describes μMET, a novel microfluidic device for precise microbial enumeration tests (MET), essential in pharmaceutical, cosmetic, and food industries for ensuring microbiological safety standards. The μMET chip, comprising two hydrophobic glass plates, features a 15-μm deep μMET chamber enhanced by nanopillars and air supply units, facilitating both immediate and growth-dependent MET. Experimental results, with E. coli as a model bacterium, demonstrate that μMET provides counting linearity that outperforms traditional hemocytometers. The chip's design mitigates challenges like evaporation and ensures high-resolution imaging, making it a cost-effective and reusable alternative to conventional methods. Notably, bright-field μMET eliminates the need for fluorescent staining, streamlining operations with deep-learning algorithms for bacterial counts. Furthermore, we have developed a high-parallel μMET chip featuring 16 counting chambers, enhancing throughput and accommodating immediate and growth-dependent MET approaches. Its innovative design and adaptability render the μMET chip as a valuable tool for microbiology, medicine, and industry applications.

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.

Effect of two insect meals on the gut commensal microbiome of healthy sea trout (Salmo trutta vr. trutta)

BACKGROUND

The balance of the intestinal commensal microbiome of fish and other animals plays an important role in the physiological processes of healthy animals, contributes to the defense against pathogens, stimulates the immune system and facilitates nutrient metabolism. In the last decade, the interest in the application of the insects in fish nutrition increased, although little is known regarding the effects of insect meals on the gastrointenstinal tract microbiome of the sea trout fingerlings. The aim of this study was to evaluate the effect of two diets containing mealworm (MW) and superworm (SW) on the microbiome of the digesta of sea trout fingerlings and the relative abundances of different taxa among communities under controlled conditions.

RESULTS

The insect meals produced a similar weight gain and survival rate to sea trout fed fishmeal. The most abundant bacterial phylum in all the treatment groups was Firmicutes followed by Proteobacteria and Actinobacteria, and significant differences in the amount of Cyanobacteria were observed in the SW group.

CONCLUSIONS

The insect meals did not produce differences in the three most abundant phyla in the sea trout digesta. However, the effect of each type of meal on the lower taxonomic levels was evident, particularly in the case of the superworm meal. These microbiome differences indicated that mealworm meal was more related to fishmeal than superworm meal. Our results highlight the potential effects of insect meals, such as mealworm and superworm meals, on the microbiota of sea trout.

Biological Characterization and Metabolic Variations among Cell-Free Supernatants Produced by Selected Plant-Based Lactic Acid Bacteria

The aim of this research was to assess the antibacterial and antioxidant properties as well as the variation in metabolites of the cell-free supernatant (CFS) produced by lactic acid bacteria (LAB) from local plants: Lactiplantibacillus plantarum ngue16, L. plantarum ng10, Enterococcus durans w3, and Levilactobacillus brevis w6. The tested strains exhibited inhibitory effects against pathogens, including Bacillus cereus, B. subtilis, Cronobacter sakazakii, Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus using the agar spot assay and well diffusion method. The CFS from all four strains displayed antibacterial activity against these pathogens with minimum inhibitory concentration (MIC) values ranging from 3.12 to 12.5 mg/mL and minimal bactericidal concentration (MBC) values ranging from 6.25 to 25.0 mg/mL. Moreover, the CFS demonstrated resilience within specific pH (3-8) and temperature (60-100 °C) ranges and lost its activity when treated with enzymes, such as Proteinase K and pepsin. Furthermore, the CFS exhibited antioxidant properties as evidenced by their ability to inhibit the formation of two radicals (1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) compared to the negative control, De Man, Rogosa, and Sharpe (MRS) broth. The use of proton-based nuclear magnetic resonance (¹H-NMR) spectroscopy revealed the presence and quantification of 48 metabolites in both the CFS and MRS broths. Principal Component Analysis (PCA) effectively differentiated between CFS and MRS broth by identifying the specific metabolites responsible for the observed differences. The partial least squares (PLS) model demonstrated a significant correlation between the metabolites in the LAB supernatant and the tested antibacterial and antioxidant activities. Notably, anserine, GABA, acetic acid, lactic acid, uracil, uridine, propylene glycol, isopropanol, serine, histidine, and indol-3-lactate were identified as the compounds contributing the most to the highest antibacterial and antioxidant activities in the supernatant. These findings suggest that the LAB strains investigated have the potential to be utilized in the production of functional foods and the development of pharmaceutical products.

Identification of Antibacterial Components and Modes in the Methanol-Phase Extract from a Herbal Plant Potentilla kleiniana Wight et Arn

The increase in bacterial resistance and the decline in the effectiveness of antimicrobial agents are challenging issues for the control of infectious diseases. Traditional Chinese herbal plants are potential sources of new or alternative medicine. Here, we identified antimicrobial components and action modes of the methanol-phase extract from an edible herb Potentilla kleiniana Wight et Arn, which had a 68.18% inhibition rate against 22 species of common pathogenic bacteria. The extract was purified using preparative high-performance liquid chromatography (Prep-HPLC), and three separated fragments (Fragments 1-3) were obtained. Fragment 1 significantly elevated cell surface hydrophobicity and membrane permeability but reduced membrane fluidity, disrupting the cell integrity of the Gram-negative and Gram-positive pathogens tested (p < 0.05). Sixty-six compounds in Fragment 1 were identified using Ultra-HPLC and mass spectrometry (UHPLC-MS). The identified oxymorphone (6.29%) and rutin (6.29%) were predominant in Fragment 1. Multiple cellular metabolic pathways were altered by Fragment 1, such as the repressed ABC transporters, protein translation, and energy supply in two representative Gram-negative and Gram-positive strains (p < 0.05). Overall, this study demonstrates that Fragment 1 from P. kleiniana Wight et Arn is a promising candidate for antibacterial medicine and food preservatives.

A Novel Strain of Probiotic Leuconostoc citreum Inhibits Infection-Causing Bacterial Pathogens

Infectious diseases caused by bacteria are at risk of spreading and prolonging due to antimicrobial resistance. It is, therefore, urgently necessary to develop a more effective antibiotic alternative strategy to control pathogen spread. In general, probiotics have been recommended as a substitute for antibiotics that inhibit pathogens. This study was isolated and probiotic characteristics and antibacterial bacterial efficiency against various infection-causing pathogens were determined by different in vitro methods. A 16S rRNA sequence confirmed that the isolated strains belonged to a species of Leuconostoc citreum. L. citreum KCC-57 and KCC-58 produced various extracellular enzymes and fermented different carbohydrates. There was significant tolerance for both strains under the harsh conditions of the gastrointestinal tract (GIT). In addition, L. citreum KCC-57 and L. citreum KCC-58 showed significant auto-aggregations and hydrophobicity properties that varied with incubation time. Moreover, the cell-free secondary supernatant (CFS) of L. citreum KCC-57 and L. citreum KCC-58 inhibited growth of Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. According to a co-culture study, L. citreum KCC-57 and L. citreum KCC-58 were highly competitive for pathogen growth. L. citreum KCC-57 and L. citreum KCC-58 showed significant probiotic potential and strong antibacterial activities against different pathogens, suggesting that these strains could be used instead of antibiotics to control infectious pathogens.

Commercial probiotic products in public health: current status and potential limitations

Consumption of commercial probiotics for health improvement and disease treatment has increased in popularity among the public in recent years. The local shops and pharmacies are brimming with various probiotic products such as probiotic food, dietary supplement and pharmaceuticals that herald a range of health benefits, from nutraceutical benefits to pharmaceutical effects. However, although the probiotic market is expanding rapidly, there is increasing evidence challenging it. Emerging insights from microbiome research and public health demonstrate several potential limitations of the natural properties, regulatory frameworks, and market consequences of commercial probiotics. In this review, we highlight the potential safety and performance issues of the natural properties of commercial probiotics, from the genetic level to trait characteristics and probiotic properties and further to the probiotic-host interaction. Besides, the diverse regulatory frameworks and confusing probiotic guidelines worldwide have led to product consequences such as pathogenic contamination, overstated claims, inaccurate labeling and counterfeit trademarks for probiotic products. Here, we propose a plethora of available methods and strategies related to strain selection and modification, safety and efficacy assessment, and some recommendations for regulatory agencies to address these limitations to guarantee sustainability and progress in the probiotic industry and improve long-term public health and development.

Ensiled Mixed Vegetables Enriched Carbohydrate Metabolism in Heterofermentative Lactic Acid Bacteria

This study evaluated the fermentation quality, nutritive profile, in vitro fermentation, and microbial communities colonising sorghum ensiled with an unsalable vegetable mixture (chopped beans, carrot, and onion (1:1:1) ) including: (1)−100% sorghum; (2)−80% sorghum + 20% vegetable mix or (3)−60% sorghum + 40% vegetable mix, on a dry matter (DM) basis, with or without a probiotic inoculant. Samples were obtained across 0, 1, 3, 5,7, and 101 days ensiling and after 14 d aerobic exposure. The V4 region of the 16S rRNA gene and the ITS1 region were sequenced to profile bacterial, archaeal, and fungal communities. Compared to the 0% DM, ethanol increased (p < 0.01) from 8.42 to 20.4 ± 1.32 mM with 40% DM vegetable mix inclusion, while lactate decreased from 5.93 to 2.24 ± 0.26 mM. Linear discriminant analysis revealed that relative abundances of 12 bacterial taxa were influenced by silage treatments (log LDA score ≥ 4.02; p ≤ 0.03), while predicted functional pathways of alternative carbohydrate metabolism (hexitol, sulfoquinovose and glycerol degradation; N-acetyl glucosamine biosynthesis; log LDA score ≥ 2.04; p ≤ 0.02) were similarly enriched. This study indicated that carbohydrate metabolism by heterofermentative lactic acid bacteria can increase the feed value of sorghum when ensiled with an unsalable vegetable mixture at 40%DM, without requiring a high quantity of lactate.

Identification and Genetic Diversity of Amylase Producing Lactic Acid Bacteria from Brown Rice (Oryza nivara) Wakawondu Cultivar Based on 16S rRNA Gene

This study identified the genetic diversity of amylase-producing lactic acid bacteria from brown rice (Oryza nivara) Wakawondu cultivar based on the 16S rRNA gene. The ten lactic acid bacteria strains were isolated from the fermented Wakawondu rice washing water; two isolates, SBM3D and SBM4A, displayed strong amylase activity. The two isolates had the same characteristics according to both morphological and biochemical examination. The effect of fermentation time on SBM3D bacterial isolates revealed that bacterial growth at 12 h with OD values and enzyme activity, respectively, of 0.856 and 175 mU/mL, was nearly identical to the growth at 27 h with OD values of 0.886 and 176 mU/mL consecutively. Meanwhile, the bacterial isolate of SBM4A showed a significant increase in growth at 15 h with an OD value of 0.552 and enzyme activity of 99 U/mL. The maximum growth was seen at 18 h with an OD value of 0.657 and enzyme activity of 126 mU/mL. Cladogram of an SBM3D isolate with Pediococcus pentosaceus strains SL001 CP039378.1 and SRCM102740 CP028269.1 forming a sister group clad. Pediococcus pentosaceus strains SRCM102739 CP028266.1 and SRCM102738 CP028264.1 form a sister group in the cladogram of the SBM4A isolate. SBM3D and SBM4A, which are amylase-producing Pediococcus pentosaceus, can be used in food, chemical, health, and other industries.

Tannin tolerance lactic acid bacteria screening and their effects on fermentation quality of stylo and soybean silages

Some excellent legume forages are difficult to ensile naturally due to their high buffering capacity and low water-soluble carbohydrate content. This may cause serious problems like proteolysis. In the present study, strains of lactic acid bacteria with high acid productivity and high tannin tolerance were screened from different silages and combined with tannic acid (TA) as an addition to ensiling. The screened strains were identified as Lactobacillus plantarum (LP), with four of these strains then selected for their high tannin tolerance. Stylosanthes guianensis and whole-plant soybean (WPS) were ensiled with 1 and 2% (fresh matter basis) TA, four LP strains alone (6 log₁₀ colony forming units per gram of fresh matter), or TA combined with LP strains. Fermentation parameters and in vitro rumen fermentation characteristics were analyzed after 30 days of fermentation. The results showed that TA + LP can be used to reduce pH values (P < 0.01), non-protein nitrogen (P < 0.01), and ammonia-nitrogen (P < 0.01). The in vitro crude protein digestibility of WPS silage was also decreased with the addition of TA + LP (P < 0.01). These results indicate that the addition of TA combined with tannin tolerance LP strains may improve the fermentation quality of legume silage, especially for reducing proteolysis.

Dynamics of the fermentation quality and microbiota in Ephedra sinica treated native grass silage

AIMS

This study aimed to evaluate the effects of Ephedra sinica on physicochemical characteristics and bacterial community of ensiled native grass by multiple physicochemical analyses combined with high-throughput sequencing.

METHODS AND RESULTS

Treatments were a control treatment with no additive (CON), Ephedra sinica was added at 1% (CEa1), 3% (CEa2) and 5% of the fresh materials (CEa3). Compared to the CON group, the dry matter and water-soluble carbohydrate contents were significantly (p < 0.05) decreased in the CEa1 group. Compared to the CON group, the pH was significantly (p < 0.05) decreased in Ephedra sinica treated silages, and the higher lactic acid content was observed in Ephedra sinica treated silages. At the genus level, the abundance of Enterococcus, Lactobacillus, Pediococcus and Weissella were the predominant member in the CON, CEa1, CEa2 and CEa3 groups, respectively. The abundance of Lactobacillus was significantly (p < 0.05) increased in the CEa1 group and Pediococcus was significantly (p < 0.05) increased in the CEa2 group. According to the 16S rRNA gene-predicted functional profiles, the inoculation of Ephedra sinica accelerated the carbohydrate metabolism.

CONCLUSIONS

In summary, the addition of Ephedra sinica could improve the silage quality of native grass by regulating the bacterial community and the addition of a 1% percentage of fresh materials exhibited the potential possibility in responding to get high-quality native grass silages.

SIGNIFICANCE AND IMPACT OF THE STUDY

The utilization of herbal additives on fermentation quality combined with 16S rRNA gene-predicted functional analyses will contribute to the direction of future research in improving silage quality.

Metaprofiling of the bacterial community in sorghum silages inoculated with lactic acid bacteria

AIMS

to characterize the fermentation process and bacterial diversity of sorghum silage inoculated with Lactiplantibacillus plantarum LpAv, Pediococcus pentosaceus PpM and Lacticaseibacillus paracasei LcAv.

METHODS AND RESULTS

chopped sorghum was ensiled using the selected strains. Physicochemical parameters (Ammonia Nitrogen/Total Nitrogen, Dry Matter, Crude Protein, Acid Detergent Fiber, Neutral Detergent Fiber, Acid Detergent Lignin, Ether Extract and Ashes), bacterial counts, cell cytometry and 16sRNA sequencing were performed to characterize the ensiling process and an animal trial (BALB/c mice) was conducted in order to preliminary explore the potential of sorghum silage to promote animal gut health. After 30 days of ensiling, the genus Lactobacillus comprised 68.4 ± 2.3 % and 73.5 ± 1.8 % of relative abundance, in control and inoculated silages respectively. Richness (Chao1 index) in inoculated samples, but not in control silages, diminished along ensiling, suggesting the domination of fermentation by the inoculated LAB. A trend in conferring enhanced protection against Salmonella infection was observed in the mouse model used to explore the potential to promote gut health of sorghum silage.

CONCLUSIONS

the LAB strains used in this study were able to dominate sorghum fermentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

this is the first report using metaprofiling of 16sRNA to characterize sorghum silage, showing a microbiological insight where resident and inoculated LAB strains overwhelmed the epiphytic microbiota, inhibiting potential pathogens of the genus Klebsiella.

Preventive Effect of Limosilactobacillus fermentum SCHY34 on Lead Acetate-Induced Neurological Damage in SD Rats

Lead poisoning caused by lead pollution seriously affects people's health. Lactic acid bacteria has been shown to be useful for biological scavenging of lead. In this experiment, Sprague-Dawley (SD) rats were treated with 200 mg/L of lead acetate solution daily to induce chronic lead poisoning, and oral Limosilactobacillus fermentum (L. fermentum) SCHY34 to study its mitigation effects and mechanisms on rat neurotoxicity. The L. fermentum SCHY34 showed competent results on in vitro survival rate and the lead ion adsorption rate. Animal experiments showed that L. fermentum SCHY34 maintained the morphology of rat liver, kidney, and hippocampi, reduced the accumulation of lead in the blood, liver, kidney, and brain tissue. Further, L. fermentum SCHY34 alleviated the lead-induced decline in spatial memory and response capacity of SD rats, and also regulated the secretion of neurotransmitters and related enzyme activities in the brain tissue of rats, such as glutamate (Glu), monoamine oxidase (MAO), acetylcholinesterase (AchE), cyclic adenosine monophosphate (cAMP), and adenylate cyclase (AC). In addition, the expression of genes related to cognitive capacity, antioxidation, and anti-apoptotic in rat brain tissues were increased L. fermentum SCHY34 treatment, such as brain-derived neurotrophic factor (BDNF), c-fos, c-jun, superoxide dismutase (SOD)1/2, Nuclear factor erythroid 2-related factor 2 (Nrf2), and B-cell lymphoma 2 (Bcl-2), and so on. L. fermentum SCHY34 showed a great biological scavenging and potential effect on alleviating the toxicity of lead ions.

The Potential of Pre-fermented Juice or Lactobacillus Inoculants to Improve the Fermentation Quality of Mixed Silage of Agro-Residue and Lucerne

The objective of this study was to determine the effect of pre-fermented juice, Lactobacillus plantarum, and L. buchneri on chemical composition, fermentation, aerobic stability, dynamics of microbial community, and metabolic pathway of a mixture of lucerne, wheat bran (WB), and rice straw (RS). All mixtures were ensiled for 1, 3, 5, 7, 15, 30, and 45 days after treatment with uninoculated (control, C); L. plantarum [LP, 1 × 106 cfu/g of fresh weight (FW)]; L. buchneri (LB, 1 × 106 cfu/g of FW); LP + LB (LPB, 1 × 106 cfu/g of FW of each inoculant); and pre-fermented juice (J; 2 × 106 cfu/g of FW). Four lactic acid bacteria (LAB) species from three genera were cultured from the pre-fermented juice, with W. cibaria being dominant. The inoculants increased lactic acid (LA), decreased pH and ammonia nitrogen (AN) compared to C silage at earlier stages of ensiling, and high dry matter (DM) and water-soluble carbohydrate (WSC) content in inoculated silages. Adding LPB increased the abundance of L. plantarum, L. paralimentarius, and L. nodensis, resulting in the lowest pH. Pre-fermented juice enriched W. cibaria, L. sakei, L. parabrevis, Pseudomonas putida, and Stenotrophomonas maltophilia, mainly enhanced accumulation of acetic acid (AA) and LA, and decreased pH, crude protein losses, AN, and hemicellulose contents. L. buchneri and L. brevis had a high abundance in LB-treated and J silages, respectively, inhibited undesirable bacteria, and improved aerobic stability with more than 16 days. In addition, the metabolic pathways changed with time and L. buchneri inoculants promoted global metabolism. In conclusion, inoculations altered bacterial succession and metabolic pathways in silage; LB and pre-fermented juice enhanced ensiling by promoting pH reductions, enhancing concentrations of LA and AA, and extending aerobic stability more than 16 days.

Improved performance and microbial community dynamics in anaerobic fermentation of triticale silages at different stages

Production of high-quality grass-based silages by microbial-mediated anaerobic fermentation is an effective strategy in livestock farms. In the present study, an ensiling process was used to preserve and enhance fermentative metabolites in triticale silages with novel inoculants of Lactobacillus rhamanosus -52 and, Lactobacillus rhamanosus-54. Triticale silages treated with LAB predominantly had lower pH values than control silages due to rapid changes of microbial counts. LAB addition improved anaerobic fermentation profiles showing higher lactic acid, but lower acetic acid and butyric acid concentrations. A background microbial dynamic study indicated that the addition of L. rhamanosus-52 and L. rhamanosus-54 improved silage fermentation, enriched Lactobacillus spp., and decreased microbial richness with diversity, leading to increased efficiency of lactic acid fermentation. In conclusion, LAB treatment can increase silage quality by enhancing the dominance of desirable Lactobacillus while inhibiting the growth of undesirable microbes.

Pediococcus pentosaceus: Screening and Application as Probiotics in Food Processing

Lactic acid bacteria (LAB) are vital probiotics in the food processing industry, which are widely spread in food additives and products, such as meat, milk, and vegetables. Pediococcus pentosaceus (P. pentosaceus), as a kind of LAB, has numerous probiotic effects, mainly including antioxidant, cholesterol-lowering, and immune effects. Recently, the applications in the probiotic- fermentation products have attracted progressively more attentions. However, it is necessary to screen P. pentosaceus with abundant functions from diverse sources due to the limitation about the source and species of P. pentosaceus. This review summarized the screening methods of P. pentosaceus and the exploration methods of probiotic functions in combination with the case study. The screening methods included primary screening and rescreening including gastric acidity resistance, bile resistance, adhesion, antibacterial effects, etc. The application and development prospects of P. pentosaceus were described in detail, and the shortcomings in the practical application of P. pentosaceus were evaluated to make better application of P. pentosaceus in the future.

Isolation of Lactococcus lactis from Whole Crop Rice and Determining Its Probiotic and Antimicrobial Properties towards Gastrointestinal Associated Bacteria

Antimicrobial resistance is an emerging condition that increases the risk of spreading and prolonging infectious diseases globally. Therefore, a new alternative strategy for antibiotics is required urgently to control pathogens spreading. Probiotics are considered as an alternative for antibiotics that inhibit pathogens. In the present study, potent lactic acid bacteria (LAB) were isolated and screened for their probiotic characteristics and antagonistic activity against intestinal pathogens by agar well diffusion, Time and Dose-dependent killing assay, minimum inhibitor, and minimum bactericidal concentration (MIC/MBC), and co-culture methods. The Lactococcus lactis RWP-3 and RWP-7 fermented the different carbohydrate substrates and produced different extracellular enzymes. Both isolates showed significant tolerant capability in the gastric, duodenal, and intestinal juices. In addition, RWP-3 and RWP-7 had hydrophobicity and aggregation properties in a time-dependent manner. Furthermore, the cell-free secondary metabolites (CFS) of RWP-3 and RWP-7 showed strong antibacterial activity against Escherichia coli,Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis. A co-culture study revealed that the RWP-3 and RWP-7 strongly compete with pathogen growths. RWP-3 and RWP-7 showed strong antagonistic activities against tested pathogens with significant probiotic characteristics, suggesting that these strains obtained could be used as an alternative strategy for the antibiotic to control infectious pathogens.

Rapid cell counting and viability detection method of Escherichia coli Nissle using image cytometry

The improvement of cell enumeration methods for the counting of Escherichia coli (E. coli) is important as E. coli gains in popularity as a basis for biopharmaceutical applications. In the biopharmaceutical industry, enumerating, characterizing, and dosing the accurate number of cells is imperative. In this work, we demonstrate the utilization of a chip-based image cytometer using a thin-gap, low volume counting chamber consumable to directly enumerate E. coli in bright field and fluorescence, and measure their viability using SYTOX™ Green. The total E. coli particles can be counted accurately label-free by adjusting the focus and targeting the linear range of the instrument. The E. coli are stained with SYTOX™ Green to count the membrane-compromised dead bacterial cells in the green fluorescence channel, while the total cells are counted using the bright field channel. Optimization of the system settings, image focus, cell counting range, and staining conditions have yielded a precise, rapid, and accurate E. coli cell enumeration and viability measurement.

Challenges and opportunities for the production of lactic acid bacteria inoculants aimed for ensiling processes

The use of bacterial inoculants for ensiling based on lactic acid bacteria (LAB) to obtain conserved forages has become an alternative for the improvement of milk and meat productivity in cattle, specifically by optimizing the nutritional and microbial quality of animal feed. LAB inoculant production involves microbial and technological aspects such as biomass obtention, the use of cocultures, the inclusion of probiotics, the production of antimicrobial peptides, operational methods used in bioreactors, and the formulation of the end product to be commercialized to farmers. This review explores the technical aspects of the manufacture of bacterial inoculants, from the main features desired in LAB for ensiling purposes to the alternatives of the bioprocess involved.

Selective Thermotolerant Lactic Acid Bacteria Isolated From Fermented Juice of Epiphytic Lactic Acid Bacteria and Their Effects on Fermentation Quality of Stylo Silages

The aim of the present study was to isolate and identify lactic acid bacteria (LAB) from fermented juice of tropical crops such as Napier grass, Ruzi grass, Purple guinea grass, Stylo legume, and Leucaena and their application to improve the quality of tropical crop silage. Fifteen strains of LAB were isolated. The LAB strains were Gram-positive and catalase-negative bacteria and could be divided into three groups, i.e., Pediococcus pentosaceus, Lactiplantibacillus (para)plantarum, and Limosilactobacillus fermentum according to the biochemical API 50CH test. Based on the analysis of 16S rRNA sequence, the strains isolated in the group L. (para)plantarum were distinguished. Two isolates (N3 and G4) were identified as Lactiplantibacillus plantarum. Three isolates (St1, St2, and St3) were identified as L. paraplantarum. In addition, the identification of other isolates was confirmed in the group P. pentosaceus (R1, R4, R5, R8, R11, and L1) and the group L. fermentum (N4, G6, G7, and N4). All selected strains were able to grow at 50°C. All LAB strains showed antimicrobial activity against Escherichia coli ATCC 25922, Shigella sonnei ATCC 25931, Pseudomonas aeruginosa ATCC 27853, and Bacillus cereus ATCC 11778. Four selected LAB strains (St1, St3, N4, and R4) were tested for their capacity to successfully ensile Stylo legume (Stylosanthes guianensis CIAT184). Stylo silages treated with LAB were well preserved, the NH₃–N and butyric acid contents were lower, and the lactic acid content was higher than those in the control (p < 0.05). The acetic acid content was the highest in R4-treated silage among the treatments (p < 0.05). The crude protein (CP) content of St1-silage was significantly (p < 0.05) higher than the others. The inoculation of thermotolerant LAB selected from fermented juice of epiphytic lactic acid bacteria (FJLB) was found to be highly instrumental to obtain well-preserved silage from the Stylo legume.

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

The objective of this study was to isolate and characterize lactic acid bacteria with probiotic potential in silages of different species of forage plants, cocoa beans, and artisanal salami. The obtained isolates were submitted to the following evaluations: (i) screening for tolerance to pH 2 and bile salts, (ii) genotypic identification of isolates, (iii) survival in simulated gastric and pancreatic conditions, (iv) antimicrobial activity, (v) antibiotic susceptibility and safety, and (vi) properties associated with adhesion capacity. A total of 82 isolates were obtained and were screened for pH 2.0 tolerance and capacity to growth in the presence of bile salts (1.0 and 2.0%). Only 19 strains simultaneously presented tolerance to pH 2.0 and bile salts. These 19 strains were evaluated for genetic profile by Box-PCR. Subsequently, the selected strains were subjected to partial sequencing of the 16S rRNA gene. The species Lactobacillus plantarum was prevalent. The identified strains were evaluated for survival under simulated gastric and pancreatic conditions. Some strains have shown tolerance in both conditions. Different strains showed variations in antimicrobial activity, susceptibility to antibiotics, and properties associated with adhesion (hydrophobicity, autoaggregation, coaggregation, and adhesion to CaCo2 cells). All strains were negative for hemolysis, DNase, gelatinase, and biogenic amine synthesis activity. The L. plantarum SBR64.7 strain can be considered the most promising for it presented the lowest viability reduction when exposed to gastric and pancreatic juices.

Pediococcus pentosaceus, a future additive or probiotic candidate

Background

Pediococcus pentosaceus, a promising strain of lactic acid bacteria (LAB), is gradually attracting attention, leading to a rapid increase in experimental research. Due to increased demand for practical applications of microbes, the functional and harmless P. pentosaceus might be a worthwhile LAB strain for both the food industry and biological applications.

Results

As an additive, P. pentosaceus improves the taste and nutrition of food, as well as the storage of animal products. Moreover, the antimicrobial abilities of Pediococcus strains are being highlighted. Evidence suggests that bacteriocins or bacteriocin-like substances (BLISs) produced by P. pentosaceus play effective antibacterial roles in the microbial ecosystem. In addition, various strains of P. pentosaceus have been highlighted for probiotic use due to their anti-inflammation, anticancer, antioxidant, detoxification, and lipid-lowering abilities.

Conclusions

Therefore, it is necessary to continue studying P. pentosaceus for further use. Thorough study of several P. pentosaceus strains should clarify the benefits and drawbacks in the future.

Criteria for lactic acid bacteria screening to enhance silage quality

The main challenge of ensiling is conserving the feed through a fermentative process that results in high nutritional and microbiological quality while minimizing fermentative losses. This challenge is of growing interest to farmers, industry and research and involves the use of additives to improve the fermentation process and preserve the ensiled material. Most studies involved microbial additives; lactic acid bacteria (LAB) have been the focus of much research and have been widely used. Currently, LABs are used in modern and sustainable agriculture because of their considerable potential for enhancing human and animal health. Although the number of studies evaluating LABs in silages has increased, the potential use of these micro-organisms in association with silage has not been adequately studied. Fermentation processes using the same strain produce very different results depending on the unique characteristics of the substrate, so the choice of silage inoculant for different starting substrates is of extreme importance to maximize the nutritional quality of the final product. This review describes the current scenario of the bioprospecting and selection process for choosing the best LAB strain as an inoculant for ensiling. In addition, we analyse developments in the fermentation process and strategies and methods that will assist future studies on the selection of new strains of LAB as a starter culture or inoculant.

Low-Carbohydrate Tolerant LAB Strains Identified from Rumen Fluid: Investigation of Probiotic Activity and Legume Silage Fermentation

The objective of this study was to isolate and characterize lactic acid bacteria (LAB) with low carbohydrate tolerance from rumen fluid and to elucidate their probiotic properties and the quality of fermentation of Medicago sativa L. and Trifolium incarnatum L. silage in vitro. We isolated 39 LAB strains and screened for growth in MRS broth and a low-carbohydrate supplemented medium; among them, two strains, Lactiplantibacillus plantarum (Lactobacillus plantarum) RJ1 and Pediococcus pentosaceus S22, were able to grow faster in the low-carbohydrate medium. Both strains have promising probiotic characteristics including antagonistic activity against P. aeruginosa, E. coli, S. aureus, and E. faecalis; the ability to survive in simulated gastric-intestinal fluid; tolerance to bile salts; and proteolytic activity. Furthermore, an in vitro silage fermentation study revealed that alfalfa and crimson clover silage inoculated with RJ1 and S22 showed significantly decreased pH and an increased LAB population at the end of fermentation. Also, the highest lactic acid production was noted (p < 0.05) in LAB-inoculated silage vs. non-inoculated legume silage at high moisture. Overall, the data suggest that RJ1 and S22 could be effective strains for fermentation of legume silage.

Probiotic Characteristics and Antifungal Activity of Lactobacillus plantarum and Its Impact on Fermentation of Italian Ryegrass at Low Moisture

The study aimed to investigate probiotic characteristics, and low moisture silage fermentation capability of selected lactic acid bacteria (LAB) isolated from Alfalfa (Medicago sativa L). Morphological and physiological properties, carbohydrates fermentation, enzymes, and organic acids production, anti-fungal activity, antibiotic sensitivity patterns, and probiotic characteristics (acidic and bile salt tolerances, hydrophobicity and aggregations natures) of LAB were examined. 16SrRNA sequencing was carried out to identify isolated strains. The identified strains Lactobacillus plantarum (KCC-37) and Lactobacillus plantarum (KCC-38) showed intense antifungal activity, survival tolerant in acidic and bile salt environments, cell surface and auto aggregations ability, enzymes and organic acids productions. At ensiled condition, KCC-37 and KCC-38 enhanced acidification of Italian ryegrass silages by producing a higher amount of lactic acid, a key acid for indicating silage quality with less extent to acetic acid and succinic acid at low moisture level than non-inoculated silages. Notably, the addition of mixed strains of KCC-37 and KCC-38 more potentially enhanced acidification of silage and organic acid productions than the single-culture inoculation. The overall data suggested that these strains could be used as an additive for improving the quality of the fermentation process in low moisture silage with significant probiotic characteristics.