In vitro properties of potential probiotic lactic acid bacteria originating from Ghanaian indigenous fermented milk products

Enterococcus durans 98D alters gut microbial composition and function to improve DSS-induced colitis in mice

Enterococcus durans, is a potential functional strain with the capacity to regulate intestinal health and ameliorate colonic inflammation. However, the strain requires further investigation regarding its safety profile and potential mechanisms of colitis improvement. In this study, the safety of E. durans 98D (Ed) as a potential probiotic was studied using in vitro methods. Additionally, a dextran sulfate sodium (DSS)-induced murine colitis model was employed to investigate its impact on the intestinal microbiota and colitis. In vitro antimicrobial assays revealed Ed sensitivity to common antibiotics and its inhibitory effect on the growth of Escherichia coli O157, Streptococcus pneumoniae CCUG 37328, and Staphylococcus aureus ATCC 25923. To elucidate the functional properties of Ed, 24 weight-matched 6-week-old female C57BL/6J mice were randomly divided into three groups (n = 8): NC group, Con group (DSS), and Ed group (DSS + Ed). Ed administration demonstrated a protective effect on colitis mice, as evidenced by improvements in body weight, colonic length, reduced disease activity index, histological scores, diminished splenomegaly, and decreased goblet cell loss. Furthermore, Ed downregulated the expression of the pro-inflammatory cytokine genes (IL-6, IL-1β, and TNF-α) and upregulated the expression of the anti-inflammatory cytokine gene IL-10. The 16S rRNA gene sequencing revealed significant alterations in microbial α-diversity, with principal coordinate analysis indicating distinct differences in microbial composition among the three groups. At the phylum level, the relative abundance of Actinomycetota significantly increased in the Ed-treated group. At the genus level, Ed treatment markedly elevated the relative abundance of Paraprevotella, Rikenellaceae_RC9, and Odoribacter in DSS-induced colitis mice. In conclusion, Ed exhibits potential as a safe and effective therapeutic agent for DSS-induced colitis by reshaping the colonic microbiota.

An overview of fermentation in the food industry - looking back from a new perspective

Fermentation is thought to be born in the Fertile Crescent, and since then, almost every culture has integrated fermented foods into their dietary habits. Originally used to preserve foods, fermentation is now applied to improve their physicochemical, sensory, nutritional, and safety attributes. Fermented dairy, alcoholic beverages like wine and beer, fermented vegetables, fruits, and meats are all highly valuable due to their increased storage stability, reduced risk of food poisoning, and enhanced flavor. Over the years, scientific research has associated the consumption of fermented products with improved health status. The fermentation process helps to break down compounds into more easily digestible forms. It also helps to reduce the amount of toxins and pathogens in food. Additionally, fermented foods contain probiotics, which are beneficial bacteria that help the body to digest food and absorb nutrients. In today's world, non-communicable diseases such as cardiovascular disease, type 2 diabetes, cancer, and allergies have increased. In this regard, scientific investigations have demonstrated that shifting to a diet that contains fermented foods can reduce the risk of non-communicable diseases. Moreover, in the last decade, there has been a growing interest in fermentation technology to valorize food waste into valuable by-products. Fermentation of various food wastes has resulted in the successful production of valuable by-products, including enzymes, pigments, and biofuels.

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.

Evaluating the Probiotic Potential of Lactic Acid Bacteria Implicated in Natural Fermentation of Table Olives, cv. Cobrançosa

The probiotic features of Lactiplantibacillus (L.) pentosus and L. paraplantarum strains, endogenous in Cobrançosa table olives from northeast Portugal, were assessed in terms of functional properties and health benefits. Fourteen lactic acid bacteria strains were compared with Lacticaseibacillus casei from a commercial brand of probiotic yoghurt and L. pentosus B281 from Greek probiotic table olives, in attempts to select strains with higher probiotic performances than those references. For functional properties, the i53 and i106 strains, respectively, exhibited: 22.2 ± 2.2% and 23.0 ± 2.2% for Caco-2 cell adhesion capacity; 21.6 ± 7.8% and 21.5 ± 1.4% for hydrophobicity; 93.0 ± 3.0% and 88.5 ± 4.5% for autoaggregation ability by 24 h of incubation; and ability to co-aggregate with selected pathogens-from 29 to 40% to Gram+ (e.g., Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212); and from 16 to 44% for Gram- (e.g., Escherichia coli ATCC 25922 and Salmonella enteritidis ATCC 25928). The strains proved to be resistant (i.e., halo zone ≤14 mm) to some antibiotics (e.g., vancomycin, ofloxacin, and streptomycin), but susceptible (i.e., halo zone ≥ 20 mm) to others (e.g., ampicillin and cephalothin). The strains exhibited health-beneficial enzymatic activity (such as acid phosphatase and naphthol-AS-BI-phosphohydrolase), but not health-harmful enzymatic activity (such as β-glucuronidase and N-acetyl-β-glucosaminidase). Additionally, the antioxidant activity and cholesterol assimilation features, respectively, of the strains were 19.6 ± 2.8% and 77.5 ± 0.5% for i53, and 19.6 ± 1.8% and 72.2 ± 0.9% for i106. This study indicated that the addition of L. pentosus strains i53 and/or i106 to Cobrançosa table olives is likely to enhance the added value of the final product, in view of the associated potential benefits upon human health.

Probiotic Properties, Safety Assessment, and Aroma-Generating Attributes of Some Lactic Acid Bacteria Isolated from Iranian Traditional Cheese

Artisanal cheeses are known as the source of beneficial lactic acid bacteria (LAB). Therefore, this study aimed to isolate and characterize LAB with different proteolytic activities from Iranian artisanal white cheeses. The isolates were classified into low, medium, and high proteolytic activity clusters via K-means clustering and identified as Lactiplantibacillus (Lpb.) pentosus L11, Lpb. plantarum L33, and Enterococcus faecium L13, respectively. Some safety tests (such as resistance to antibiotics, hemolytic activity, and biogenic amine production), probiotic properties (including cell surface hydrophobicity, auto/co-aggregation, and antibacterial activity), and production of volatile compounds were evaluated. These were non-hemolytic and non-biogenic amine producers, and showed no irregular antibiotic resistance. Lpb. plantarum L33 had the highest hydrophobicity (30.55%) and auto-aggregation (49.56%), and the highest co-aggregation was observed for Lpb. pentosus L11 with Staphylococcus aureus (61.51%). The isolates also showed a remarkable antibacterial effect against pathogenic bacteria. Moreover, Lpb. pentosus L11 and Lpb. plantarum L33 with low and medium proteolytic activity produced a wider range of volatile compounds in milk compared to the strain with a high proteolytic effect. The results showed that a probiotic strain with low or medium proteolytic activity could improve the flavor characteristics of fermented milk.

In-vitro evaluation of the probiotic potential and the fermentation profile of Pediococcus and Enterococcus strains isolated from Moroccan camel milk

The promotion of human health through natural approaches like functional foods and probiotics is in high demand. The medicinal plants are the major feed of Moroccan dromedary, which improves the functional properties of their milk. A few studies have reported the probiotic and functional aptitudes of lactic acid bacteria (LAB) of this milk. In this context, our study aimed to identify LAB isolated from Moroccan raw camel milk and investigate their probiotic features and their fermentation profile. The molecular identification of twelve isolates indicated that they belong to Pediococcus pentosaceus, Enterococcus faecium, and Enterococcus durans. All LAB strains displayed high tolerance to gastrointestinal conditions (survival rate of 31.85-96.52% in pH 2.5, 35.23-99.05% in 0.3 bile salts, and 26.9-90.96% in pepsin), strong attachment abilities (auto-aggregation and hydrophobicity ranged from 28.75 to 95.9% and from 80.47 to 96.37%, respectively), and high co-aggregation ability with pathogenic bacteria. Importantly, they did not present antibiotic resistance or hemolytic activity. Our LAB strains demonstrated antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, and Salmonella enterica. Moreover, they could acidify cow milk (ΔpH of 2.55 after 24 h) and improve its antioxidant ability (inhibition of 36.77% of DPPH). Based on the multivariate analysis, Pediococcus pentosaceus Pd24, Pd29, Pd38, Enterococcus faecium Ef18, and Enterococcus durans Ed22 were selected as the most promising probiotics. Therefore, we propose that Pediococcus pentosaceus isolated from camel milk could be used as potential probiotic strains and/or starter cultures in functional milk fermentation.

A Comparative Study of Skimmed Milk and Cassava Flour on the Viability of Freeze-Dried Lactic Acid Bacteria as Starter Cultures for Yogurt Fermentation

The purpose of this study was to evaluate the survival rates and fermentation performance of three freeze-dried lactic acid bacterial cultures previously isolated from Ghanaian traditional fermented milk. LAB cultures, i.e., Lactobacillus delbrueckii, Lactococcus lactis and Leuconostoc mesenteroides, were frozen in the chamber of a Telstar (Lyoquest) laboratory freeze dryer for 10 h at -55 °C (as single and combined cultures) using skimmed milk and cassava flour as cryoprotectants held in plastic or glass cryovials. For viability during storage, freeze-dried LAB cultures were stored in a refrigerator (4 °C) and at room temperature (25 °C) for 4 weeks. The survival of freeze-dried cultures was determined by growth kinetics at 600 nm (OD600). The performance of freeze-dried LAB cultures after 4 weeks of storage was determined by their growth, acidification of milk during yogurt fermentation and consumer sensory evaluation of fermented milk using a nine-point hedonic scale. The survival rates for LAB ranged between 60.11% and 95.4% following freeze-drying. For single cultures, the highest survival was recorded for Lactobacillus delbrueckii (L12), whereas for combined cultures, the highest survival was observed for Lactococcus lactis (L3) combined with Lactobacillus delbrueckii (L12). The consumer acceptability results showed that yogurts produced from a combined starter culture of Lactococcus lactis and Lactobacillus delbrueckii or from a single culture of Lactococcus lactis were the most preferred products with Lactococcus lactis and Lactobacillus delbrueckii possessing high survival rates and high consumer acceptability in yogurt production. These findings are crucial and can be adopted for large-scale production and commercialization of yogurt.

Advantages and disadvantages of non-starter lactic acid bacteria from traditional fermented foods: Potential use as starters or probiotics

Traditional fermented foods are a significant source of starter and/or non-starter lactic acid bacteria (nsLAB). Moreover, these microorganisms are also known for their role as probiotics. The potential of nsLAB is huge; however, there are still challenges to be overcome with respect to characterization and application. In the present review, the most important steps that autochthonous lactic acid bacteria isolated from fermented foods need to overcome, to qualify as novel starter cultures, or as probiotics, in food technology and biotechnology, are considered. These different characterization steps include precise identification, detection of health-promoting properties, and safety evaluation. Each of these features is strain specific and needs to be accurately determined. This review highlights the advantages and disadvantages of nsLAB, isolated from traditional fermented foods, discussing safety aspects and sensory impact.

In vitro and genetic screening of probiotic properties of lactic acid bacteria isolated from naturally fermented cow-milk and yak-milk products of Sikkim, India

A total of 272 isolates of lactic acid bacteria (LAB) were isolated from 22 samples of naturally fermented milk products of Sikkim in India viz. dahi, soft-variety chhurpi, hard-variety chhurpi, mohi and philu, out of which, 68 LAB isolates were randomly grouped on the basis of phenotypic characteristics, and were identified by 16S rRNA gene sequence analysis. Leuconostoc mesenteroides was the most dominant genus, followed by Leuc. mesenteroides subsp. jonggajibkimchii, Lactococcus lactis subsp. cremoris, Lc. lactis, Lc. lactis subsp. hordniae, Lc. lactis subsp. tructae, Enterococcus faecalis, E. italicus and E. pseudoavium. LAB strains were tested for probiotics attributes by in vitro and genetic screening, based on marker genes. LAB strains showed tolerance to pH 3.0, bile salt, resistance to lysozyme and β-galactosidase activity. Enterococcus faecalis YS4-11 and YS4-14 and Lactococcus lactis subsp. cremoris SC3 showed more than 85% of hydrophobicity. Genes clp L and tdc encoding for low pH tolerance, agu A and Ir1516 encoding for bile tolerance, LBA1446 gene encoding for BSH activity, map A, apf, mub 1 and msa encoding for mucosal binding property were detected. Gene mesY for bacteriocin production was detected only in Leuconostoc spp. Based on the in vitro and genetic screening of probiotic attributes, Leuc. mesenteroides; Leuc. mesenteroides subsp. jonggajibkimchii and Lc. lactis subsp. cremoris were tentatively selected for possible probiotic candidates.

Probiotic potential of Weissella paramesenteroides MYPS5.1 isolated from customary dairy products and its therapeutic application

Probiotics are viable microorganisms that confer general health benefits to the host when consumed in an adequate concentration. Probiotics may also possess strain-specific therapeutic properties and therefore finding novel strains with probiotic properties is becoming increasingly important. The present study has focused on the isolation of probiotic bacteria from dairy products which possessed potential therapeutic properties. Of the 79 strains isolated, eight were selected for further studies based on a number of traits including biofilm formation, deoxyribonuclease (DNase) activity, agglutination activity, auto-aggregation activity, antibiotic resistance, and antagonistic activity. Strain MYPS5.1 was selected from the eight isolates as the best potential probiotic candidate strain and was subsequently identified as Weissella paramesenteroides by 16S rDNA gene sequencing and sequence analysis. W. paramesenteroides strain MYPS5.1 was resistant to a number of antibiotics and the strain produced a high concentration of exopolysaccharide (EPS) (380.42 mg/L). The functional groups C-H, C = C, N = N, N-H, and C-O in the EPS were identified by using Fourier transform infrared (FTIR) spectroscopy. Computational studies showed that it interacted with cyclin-dependent kinase (CDK), a molecule which is thought to play a role in cancer pathogenesis (REF). Collectively, these results suggest that Weissella paramesenteroides MYPS5.1 is a potential probiotic strain with potential therapeutic properties.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-03074-2.

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.

Characterization of a bacterial strain Lactobacillus paracasei LP10266 recovered from an endocarditis patient in Shandong, China

Background

Lactobacilli are often recognized as beneficial partners in human microbial environments. However, lactobacilli also cause diseases in human, e.g. infective endocarditis (IE), septicaemia, rheumatic vascular disease, and dental caries. Therefore, the identification of potential pathogenic traits associated with lactobacilli will facilitate the prevention and treatment of the diseases caused by lactobacilli. Herein, we investigated the genomic traits and pathogenic potential of a novel bacterial strain Lactobacillus paracasei LP10266 which has caused a case of IE. We isolated L. paracasei LP10266 from an IE patient’s blood to perform high-throughput sequencing and compared the genome of strain LP10266 with those of closely related lactobacilli to determine genes associated with its infectivity. We performed the antimicrobial susceptibility testing on strain LP10266. We assessed its virulence by mouse lethality and serum bactericidal assays as well as its serum complement- and platelet-activating ability. The biofilm formation and adherence of strain LP10266 were also studied.

Results

Phylogenetic analysis revealed that strain LP10266 was allied with L. casei and L. paracasei. Genomic studies revealed two spaCBA pilus clusters and one novel exopolysaccharides (EPS) cluster in strain LP10266, which was sensitive to ampicillin, penicillin, levofloxacin, and imipenem, but resistant to cefuroxime, cefazolin, cefotaxime, meropenem, and vancomycin. Strain LP10266 was nonfatal and sensitive to serum, capable of activating complement 3a and terminal complement complex C5b-9 (TCC). Strain LP10266 could not induce platelet aggregation but displayed a stronger biofilm formation ability and adherence to human vascular endothelial cells (HUVECs) compared to the standard control strain L. paracasei ATCC25302.

Conclusion

The genome of a novel bacterial strain L. paracasei LP10266 was sequenced. Our results based on various types of assays consistently revealed that L. paracasei LP10266 was a potential pathogen to patients with a history of cardiac disease and inguinal hernia repair. Strain LP10266 showed strong biofilm formation ability and adherence, enhancing the awareness of L. paracasei infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02253-8.

Health-Promoting Properties of Lactobacilli in Fermented Dairy Products

Bacteria of the genus Lactobacillus have been employed in food fermentation for decades. Fermented dairy products, such as cheese and yogurt, are products of high value known as functional food and widely consumed due to their positive health impact. Fermentation was originally based on conversion of carbohydrate into organic acids, mostly lactic acid, intended to preserve nutrient in milk, but then it develops in other disclosure of capabilities associates with health benefit. It is expected that during the manufacture of fermented dairy products, some bioactive peptides from milk protein are released through proteolysis. Lactobacilli have been recognized and received increasing attention as probiotics by balancing gut microbial population. Information of molecular mechanisms of genome sequence focusing on the microbial that normally inhabit gut may explain as to how these bacteria positively give impact on improving host health. Recent post-biotics concept revealed that health benefit can also be associated after bacterial lysis. This mini review focuses on the contribution of lactobacilli in dairy fermentation with health-promoting properties on human health.