In-vitro assessment of probiotic potential of Lactobacillus plantarum WU-P19 isolated from a traditional fermented herb

Biofortification, metabolomic profiling and quantitative analysis of vitamin B12 enrichment in guava juice via lactic acid fermentation using Levilactobacillus brevis strain KU15152

BACKGROUND

Chemical fortification and dose supplementation of vitamin B12 are widely implemented to combat deficiency symptoms. However, in situ, fortification of vitamin B12 in food matrixes can be a promising alternative to chemical fortification. The present study aimed to produce vitamin B12-rich, probiotic guava juice fermented with Levilactobacillus brevis strain KU15152. Pasteurized fresh guava juice was inoculated with 7.2 log CFU mL-1 L. brevis strain KU15152 and incubated for 72 h at 37 °C anaerobically. The antioxidants, total phenolic compounds, vitamin B12 production, sugars, organic acids, pH and viable count were analyzed at 24, 48 and 72 h of incubation. The fermented juice was stored at 4 °C, and the changes in its functional properties were analyzed at 7-day intervals up to 28 days of storage.

RESULTS

During fermentation, the bacteria cell count was increased from 7.01 ± 0.06 to 9.76 ± 0.42 log CFU mL-1 after 72 h of fermentation and was decreased to 6.94 ± 0.34 CFU mL-1 during storage at 4 °C after 28 days. The pH, total soluble solids, crude fiber, citric acid and total sugars decreased, while titratable acidity, total protein, antioxidants, phenolic compounds and lactic acid contents increased during fermentation. The fermented guava juice exhibited higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS)) radical scavenging activities (85.97% and 75.97%, respectively) at 48 h of fermentation. The concentration of active vitamin B12 in the sample reached 109.5 μg L-1 at 72 h of fermentation. However, this concentration gradually decreased to 70.2 μg L-1 during the storage period. During storage for 28 days at 4 °C, both the fermented and control guava juices exhibited a decline in antioxidant and phenolic compound concentrations. Furthermore, the addition of 20% honey and guava flavor enhanced the organoleptic properties and acceptability of fermented guava juice.

CONCLUSION

The value-added fermented guava juice could be a novel functional food product to combat vitamin B12 deficiency. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Transcriptional Analysis and Identification of a Peptidoglycan Hydrolase (PGH) and a Ribosomal Protein with Antimicrobial Activity Produced by Lactiplantibacillus paraplantarum

The growing challenge of antibiotic resistance has intensified the search for new antimicrobial agents. Promising alternatives include peptidoglycan hydrolases (PGHs) and certain ribosomal proteins, both of which exhibit antimicrobial activity. This study focuses on a Lactiplantibacillus paraplantarum strain, isolated from fermented meat, capable of inhibiting pathogens such as Listeria innocua, Salmonella Typhimurium, Escherichia coli, Staphylococcus aureus, and Weissella viridescens. The highest growth and antimicrobial activity were observed at a high nitrogen concentration (5.7 g/L). Two antimicrobial proteins were identified: the 50S ribosomal protein L14 (RP uL14) and 6-phospho-N-acetylmuramidase (MupG), a PGH. Partial purification and characterization of these proteins were achieved using SDS-PAGE, zymography, and LC-MS/MS. Transcriptional data (RT-qPCR) showed that higher nitrogen concentrations enhanced MupG expression, while increased carbon concentrations boosted RP uL14 expression. These findings highlight the importance of nutritional sources in maximizing the production of novel antimicrobial proteins, offering a potential path to develop effective alternatives against antibiotic-resistant bacteria.

Therapeutic Role of Secondary Metabolites from Probiotic Strains for Ehrlich Solid Tumors in Mice

This study aimed to screen the bioactive components in Streptococcus equinus WC1 (SE-WC1) and Limosilactobacillus reuteri GM4 (LR-GM4) and estimate the therapeutic role in Ehrlich solid tumors (EST) mice model. Forty-four male albino EST mice were assigned into 7 groups and treated daily for 2 weeks, including the EST group, the EST mice that received SE-WC1 at a low or a high dose (0.5 ml *106 or 0.5 ml *108 cfu), the EST mice that received LR-GM4 at the low or the high dose (0.5 ml *106 or 0.5 ml *108 cfu), and the EST mice that received SE-WC1 plus LR-GM4 at the low or the high dose. Tumors were harvested, weighed, examined, and used for the determination of apoptosis-related gene expression. Samples of the intestine, liver, and kidney were gathered for histological examination. The GC-MS identified 24 and 36 bioactive compounds in SE-WC1 and LR-GM4, respectively. The main compound in SE-WC1 was lupeol; however, the main compound in LR-GM4 was retinaldehyde. EST mice showed disturbances in Bcl-2, Bax, and p53 mRNA expression along with histological changes in the intestine, liver, and kidney. Administration of both bacterial strains reduced the tumor weight, alleviated the disturbances in the gene expression, and improved the histological structure of the intestine, liver, and kidney in a dose-dependent. Moreover, LR-GM4 was more effective than SE-WC1 due to its higher content of bioactive compounds. It could be concluded that these strains of probiotics are promising for the treatment of solid tumors.

Characterization of Bacillus spp. isolated from the intestines of Rhynchocypris lagowskii as a potential probiotic and their effects on fish pathogens

Probiotics sourced from fish intestinal microbiota have a merit over other bacterial sources due to colonization ability and effective time. This study aimed to evaluate the bacilli isolated from the Rhynchocypris lagowskii intestines and their validity as a probiotic. Three isolates were selected (LSG 2-5, LSG 3-7, and LSG 3-8) and defined by morphological and 16S rRNA analysis as Bacillus velezensis, Bacillus aryabhattai, and Bacillus mojavensis, respectively. Results showed the strain tolerant abilities to gastrointestinal fluid, bile salt, pH, and temperature expotures. Additionally, all bacterial strains showed anti-pathogenic activity against at least four strains out of six tested pathogen strains (Staphylococcus aureus, Aeromonas hydrophila, Escherichia coli, Aeromonas veronii, Edwardsiella, and Aeromonas sobria). The bacterial strains also showed a high percentage of co-aggregation activity, more than 70%, with Aer. hydrophile, Staph. epidermidis, and Klebsiella aerogenes. At the same time, the results of competition, rejection, and substitution activity with Aer. hydrophila and Aer. veronii indicated the ability of the isolated strains to reduce the adhesion of pathogens to mucin. All strains showed safety properties, non-hemolytic, and sensitivity characteristics for most of tested antibiotics. In vivo test after injecting these strains into fish at various concentrations showed no side effects in the internal or external organs of fish compared to controls, proving that this is safe for these fish. Furthermore, the three strains produced lipase, amylase, and protease enzymes. The strains also showed bile salt hydrolase activity and biofilm formation, allowing them to tolerate stressful conditions. Conclusion: Based on these strains characteristics and features, they could be considered a promising candidate probiotic and can be used as an anti-pathogenic, especially in aquaculture.

Research advances in probiotic fermentation of Chinese herbal medicines

Chinese herbal medicines (CHM) have been used to cure diseases for thousands of years. However, the bioactive ingredients of CHM are complex, and some CHM natural products cannot be directly absorbed by humans and animals. Moreover, the contents of most bioactive ingredients in CHM are low, and some natural products are toxic to humans and animals. Fermentation of CHM could enhance CHM bioactivities and decrease the potential toxicities. The compositions and functions of the microorganisms play essential roles in CHM fermentation, which can affect the fermentation metabolites and pharmaceutical activities of the final fermentation products. During CHM fermentation, probiotics not only increase the contents of bioactive natural products, but also are beneficial for the host gut microbiota and immune system. This review summarizes the advantages of fermentation of CHM using probiotics, fermentation techniques, probiotic strains, and future development for CHM fermentation. Cutting-edge microbiome and synthetic biology tools would harness microbial cell factories to produce large amounts of bioactive natural products derived from CHM with low-cost, which would help speed up modern CHM biomanufacturing.

Antimicrobial Activities and Biopreservation Potential of Lactic Acid Bacteria (LAB) from Raw Buffalo (Bubalus bubalis) Milk

The aim of this study was to investigate the antimicrobial and biopreservation potential of lactic acid bacteria. The potential probiotic culture inhibited the growth of gram-positive and gram-negative foodborne pathogens in agar spot assay with inhibition zones ranging from 10 to 21 mm in diameter. The strains showed coaggregation capabilities ranging from 7 to 71% with tested food pathogens including Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica subsp. enterica serovar Typhimurium. The effect of cell-free supernatants on the release of 260 nm absorbing material, especially nucleic acids, was evaluated and indicated the antagonistic activity on foodborne pathogens, the highest being Lactobacillus paraplantarum against E. coli (3.77) and S. aureus (3.86) after 60 min. The effect of cell-free supernatant (CFS) on the growth of pathogens showed that Lactobacillus paraplantarum 11 and L. pentosus 93 had the highest inhibitory activity against tested strains. The biopreservation assay indicated that the potential probiotic strains Lactobacillus paraplantarum 11 (BT), Lactiplantibacillus plantarum 19, Lactobacillus pentosus 42, Limosilactobacillus fermentum 60, Lactobacillus pentosus 93, and Limosilactobacillus reuteri 112 were effective in reducing the Listeria monocytogenes population in raw buffalo milk. Complete Listeria monocytogenes inhibition was observed after 6-8 days. This study showed that probiotic LAB from buffalo milk have antimicrobial and biopreservation potential; these strains have the potential to be utilized as biopreservative agents in food products.

Postbiotic metabolites, antioxidant and anticancer activities of probiotic Leuconostoc pseudomesenteroides strains in natural pickles

In this study, five strains of Leuconostoc pseudomesenteroides were thought to have probiotic properties and anticancer activity isolated from natural pickles and identified by performing the 16S rRNA sequence analysis. The probiotic properties, postbiotic amounts, the capacity to adhere to the L-929, HT-29 and Caco-2 cell lines, the effects of postbiotic and bacterial extracts on cell viability and biochemical activities were investigated in the strains. In the results, Leu. pseudomesenteroides Y6 strain was detected to have the best resistance to the stomach and intestinal environments, and the quantities of postbiotic metabolites are similar to each other. The bacterial adhesion capacities were found to be in the range of 1.66-8.5%. Furthermore, postbiotic metabolites of all isolates had good anticancer activity (27.67-86.05%) and the activity of bacterial extractions increased depending on concentration. Leu. pseudomesenteroides Y4 and Y6 strains generally showed better activity than controls and all strains were strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengers in the antioxidant studies. In conclusion, the Y6 strain, which had the best probiotic feature, was found to show significantly good biological activity. It is thought that this isolate will be supported by new in vivo studies and eventually be brought to the food and health industry.

Antimicrobial activity, environmental sensitivity, mechanism of action, and food application of αs165-181 peptide

αs165-181 is a peptide derived from αs₂-casein of ovine milk. Herein, we report the antimicrobial activity and mechanism, and food application of the peptide. αs165-181 showed antimicrobial activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes, Bacillus cereus, and Salmonella enterica serovar Enteritidis in a dose-dependent manner. The minimum inhibitory concentration of the peptide was 3.9 mg/ml for E. coli and 7.8 mg/ml for the other bacteria. The peptide did not show antimicrobial activity against Lactobacillus plantarum up to 3.9 mg/ml concentration. The minimum bactericidal concentration of αs165-181 peptide was 7.8 mg/ml for E. coli, S. aureus, L. monocytogenes, and B. cereus. The peptide was sensitive to monovalent and divalent cations, pH, and high temperatures. Transmission electron microscopy, cytoplasmic β-galactosidase leakage, and DNA electrophoresis analyses showed that αs165-181 peptide affects bacteria by damaging cell membrane and binding to the genomic DNA. When αs165-181 peptide was applied to minced beef or UHT cream, the antimicrobial activity (7.8 mg/g) was almost the same as or even better than nisin (0.5 mg/g). This study helps understand the antimicrobial mode of action of αs165-181 peptide and develop strategies for application in food products.

Nutritionally Enhanced Probioticated Whole Pineapple Juice

Nutritionally enhanced probioticated whole pineapple juice (WPJ, comprising juice of pineapple pulp and peel) beverages were produced by fermentation of WPJ with the probiotic bacterium Lactobacillus plantarum WU-P19. The 12 h fermented juice contained between 2.1 × 109 and 3.7 × 109 live cells of the probiotic per milliliter, depending on the beverage formulation. The beverage had a pH of around 4.1 and a lactic acid content of ~12.8 g L−1. It had a total sugar (glucose, sucrose, fructose, maltose) content of ~100.2 g L−1. During fermentation, some of the initial glucose and fructose were consumed by the probiotic, but sucrose and maltose were not consumed. The original WPJ was free of vitamin B12, but fermentation enhanced vitamin B12 content (~19.5 mg L−1). In addition, fermentation enhanced the concentrations of vitamins B2, B3, and B6, but the bacterium consumed some of the vitamin B1 originally present. From a nutritional perspective, the final probioticated beverage was a good source of vitamin B12, vitamin C and vitamin B6. In addition, it contained nutritionally useful levels of vitamins B1, B2, and B3. The calorific value of the final beverage was 56.94 kcal per 100 mL. The product was stable during 21-day refrigerated (4 °C) storage.

Evaluation of the Antibacterial Activity and Probiotic Potential of Lactobacillus plantarum Isolated from Chinese Homemade Pickles

This study investigated the antipathogenic activity and probiotic potential of indigenous lactic acid bacteria (LAB) isolated from Chinese homemade pickles. In total, 27 samples were collected from different sites in China. Fifty-nine yielded pure colonies were identified by 16S rRNA gene sequencing as LAB and were initially evaluated for the antibacterial activity in vitro. Initial screening yielded Lactobacillus plantarum GS083, GS086, and GS090, which showed a broad-spectrum antibacterial activity against food-borne pathogens, especially multidrug-resistant pathogens. Meanwhile, organic acids were mainly responsible for the antimicrobial activity of the LAB strains, and the most abundant of these was lactic acid (19.32 ± 0.95 to 24.79 ± 0.40 g/l). Additionally, three L. plantarum strains demonstrated several basic probiotic characteristics including cell surface hydrophobicity, autoaggregation, and survival under gastrointestinal (GI) tract conditions. The safety of these isolates was also evaluated based on their antibiotic susceptibility, hemolytic risk, bile salt hydrolase activity, and existence of virulence or antibiotic resistance genes. All strains were safe at both the genomic and phenotypic levels. Therefore, L. plantarum GS083, GS086, and GS090 are fairly promising probiotic candidates and may be favorable for use as preservatives in the food industry.

In vitro screening of probiotic properties of Lactobacillus plantarum isolated from fermented milk product

Objectives

The screening of traditional fermented products is essential for the assessment of safety, security, and further development of functional foods for the well-being of human health. The aim of the present study was to isolate and identify bacteria from fermented raw milk samples that exhibit health benefits upon consumption.

Methods

In order to confirm the isolates as probiotics, several in vitro assays were conducted to assess the probiotic properties of isolated bacteria. The initial screening includes tolerance to acid, bile, pancreatin, and NaCl. The cell surface properties demonstrate their interaction with mucosal epithelium, which includes hydrophobicity and auto-aggregation assay. Safety assessment was done by performing haemolytic test and antibiotic susceptibility test. The antagonistic activity of probiotic strain was further evaluated against some pathogenic bacteria.

Results

Lactobacillus plantarum (L. plantarum) isolated from fermented raw milk was preliminarily identified by biochemical tests and further confirmed using 16S rRNA identification. The isolate designated as L. plantarum strain GCC_19M1 demonstrated significant tolerance to low pH, 0.3% bile, 0.5% pancreatin, and 5% NaCl. In the presence of simulated gastric juice (at pH 3), the isolate exhibited a survival rate of 93.48–96.97%. Furthermore, the development of ecological niches in the human gut and their successful accumulation have been revealed by auto-aggregation and hydrophobicity properties. Absence of haemolytic activity ensures the non-virulent nature of the strain. Lactobacillus plantarum strain GCC_19M1 showed susceptibility towards gentamicin, tetracycline, kanamycin, meropenem, and ceftriaxone and exhibited an antagonistic effect on pathogenic bacteria.

Conclusion

The obtained results conveyed that L. plantarum strain GCC_19M1 has strong probiotic potential, and its presence in the fermented raw milk products may serve as a potent functional probiotic food.

Novel probiotic lactic acid bacteria isolated from indigenous fermented foods from West Sumatera, Indonesia

Background and Aim:

Probiotics play an important role in maintaining a healthy gut and consequently promote good health. This study aimed to find novel probiotic lactic acid bacteria (LAB) from indigenous fermented foods of West Sumatera, Indonesia.

Materials and Methods:

This study utilized 10 LAB previously isolated from fermented buffalo milk (dadih), fermented fish (budu), and fermented cassava (tape) which have the ability to produce gamma-aminobutyric acid. The study commenced with the screening of LAB for certain properties, such as resistance to acid and bile salts, adhesion to mucosal surface, and antagonism against enteric pathogens (Escherichia coli, Salmonella Enteritidis, and Staphylococcus aureus). The promising isolates were identified through biochemical and gram staining methods.

Results:

All isolates in this study were potential novel probiotics. They survived at a pH level of 2.5 for 3 h (55.27-98.18%) and 6 h (50.98-84.91%). Survival in bile at a concentration of 0.3% was 39.90-58.61% and the survival rate was 28.38-52.11% at a concentration of 0.5%. The inhibitory diameter ranged from 8.75 to 11.54 mm for E. coli, 7.02 to 13.42 mm for S. aureus, and 12.49 to 19.00 mm for S. Enteritidis. All the isolates (84.5-92%) exhibited the ability to adhere to mucosal surfaces. This study revealed that all the isolates were potential probiotics but N16 proved to be superior because it was viable at a pH level of 2 (84.91%) and it had a good survival rate in bile salts assay (55.07%). This isolate was identified as Lactobacillus spp., Gram-positive bacilli bacteria, and tested negative in both the catalase and oxidase tests.

Conclusion:

All the isolates in this study may be used as probiotics, with isolate N16 (Lactobacillus spp.) as the most promising novel probiotic for poultry applications based on its ability to inhibit pathogenic bacteria.

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.

Probiotic Properties of Lactic Acid Bacteria Isolated From Neera: A Naturally Fermenting Coconut Palm Nectar

Probiotic bacteria were isolated from different traditional fermented foods as there are several such foods that are not well explored for their probiotic activities. Hence, the present study was conducted to find the potential of lactic acid bacteria (LAB) as probiotics that were isolated from the sap extract of the coconut palm inflorescence - Neera, which is a naturally fermented drink consumed in various regions of India. A total of 75 isolates were selected from the Neera samples collected aseptically in the early morning (before sunrise). These isolates were initially screened for cultural, microscopic, and biochemical characteristics. The initial screening yielded 40 Gram-positive, catalase-negative isolates that were further subjected to acid - bile tolerance with resistance to phenol. Among 40 isolates, 16 survived screening using analysis of cell surface hydrophobicity, auto aggregation with adhesion to epithelial cells, and gastric-pancreatic digestion for gastrointestinal colonization. The isolates were also assessed for antimicrobial, antibiotic sensitivity, and anti-oxidative potential. The safety of these isolates was evaluated by their hemolytic and deoxyribonuclease (DNase) activities. Based on these results, seven isolates with the best probiotic attributes were selected and presented in this study. These LAB isolates, with 51.91-70.34% survival at low pH, proved their resistance to gastric conditions. The cell surface hydrophobicity of 50.32-77.8% and auto aggregation of 51.02-78.95% represented the adhesion properties of these isolates. All the seven isolates exhibited good antibacterial and antifungal activity, showing hydroxyl-scavenging activity of 32.86-77.87%. The results proved that LAB isolated from Neera exhibited promising probiotic properties and seem favorable for use in functional fermented foods as preservatives.