Phenotypic and genotypic screening of human-originated lactobacilli for vitamin B12 production potential: process validation by micro-assay and UFLC

Exploiting Potential Probiotic Lactic Acid Bacteria Isolated from Chlorella vulgaris Photobioreactors as Promising Vitamin B12 Producers

Lactic acid bacteria (LAB) have been documented as potential vitamin B12 producers and may constitute an exogenous source of cobalamin for the microalga Chlorella vulgaris, which has been described as being able to perform vitamin uptake. Hence, there is an interest in discovering novel B12-producing probiotic LAB. Therefore, the purpose of the current work was to perform a phenotype-genotype analysis of the vitamin B12 biosynthesis capacity of LAB isolated from C. vulgaris bioreactors, and investigate their probiotic potential. Among the selected strains, Lactococcus lactis E32, Levilactobacillus brevis G31, and Pediococcus pentosaceus L51 demonstrated vitamin B12 biosynthesis capacity, with the latter producing the highest (28.19 ± 2.27 pg mL-1). The genomic analysis confirmed the presence of pivotal genes involved in different steps of the biosynthetic pathway (hemL, cbiT, cobC, and cobD). Notably, P. pentosaceus L51 was the only strain harboring cobA, pduU, and pduV genes, which may provide evidence for the presence of the cobalamin operon. All strains demonstrated the capability to withstand harsh gastrointestinal conditions, although P. pentosaceus L51 was more resilient. The potential for de novo cobalamin biosynthesis and remarkable probiotic features highlighted that P. pentosaceus L51 may be considered the most promising candidate strain for developing high-content vitamin B12 formulations.

Vitamin B12 biofortification of soymilk through optimized fermentation with extracellular B12 producing Lactobacillus isolates of human fecal origin

The present study was designed to bio-fortify the soymilk (per se a B12-free plant food matrix). The PCR-based screening characterized the human fecal samples (4 out of 15 tested) and correspondingly identified novel lactobacilli isolates (n = 4) for their B12 production potential and rest (n = 62) as negative for this attribute. Further, 3 out of the 4 selected strains showed ability for extracellular vitamin production. The most prolific strain, Lactobacillus reuteri F2, secreted B12 (132.2 ± 1.9 μg/L) in cobalamin-free-medium with the highest ratio ever reported (0.97:1.00; extra-: intra-cellular). In next stage, the soymilk was biofortified in situ with B12 during un-optimized (2.8 ± 0.3 μg/L) and optimized (156.2 ± 3.6 μg/L) fermentations with a ∼54-fold increase at Artificial Neuro Fuzzy Inference System based R value of >0.99. The added-nutrients, temperature and initial-pH were observed to be the most important fermentation variables for maximal B12 biofortification. We report Lactobacillus rhamnosus F5 as the first B12 producing (101.7 ± 3.4 μg/L) strain from this species. The cyanocobalamin was extracted, purified and separated on UFLC as nutritionally-relevant B12. Besides, the vitamin was bioavailable in an auxotrophic-mutant. The lactobacilli fermentation is suggested, therefore, as an effective approach for B12 biofortification of soymilk.

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PCR-based real-time screening of human fecal samples for the presence of B12-related cbiK gene.

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Novel report of B12 production in Lactobacillus rhamnosus species (strain F5).

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A rare B12-producing phenotype of Lactobacillus reuteri F2 with highest ever ratio of extracellular vs total B12 (0.95:1.0).

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Sequential optimization (OFAT .→ GSD → ANFIS) enhanced post-fermentation soymilk B12 levels by 54-folds.

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One serving size (100 mL) of L. reuteri F2-biofortified fermented soymilk offered 6.5-fold higher B12 than human RDA.

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The produced B12 form is nutritionally-relevant and biologically active for humans.

Probiotic Lactobacillus johnsonii BS15 Promotes Growth Performance, Intestinal Immunity, and Gut Microbiota in Piglets

Numerous studies have investigated the beneficial effects of Lactobacillus johnsonii strain BS15 on mice and broilers. This study aimed to understand the growth-promoting effects of BS15 on piglets. We determined the effects of L. johnsonii BS15 and a commercial probiotic strain, Bacillus subtilis JS01. Seventy-two suckling piglets (1 ± 2-day-old) were divided into three groups and fed with diets supplemented with 1 × 10⁶ colony-forming units (cfu) BS15 per gram of feed (BS15 group); 1 × 10⁶ cfu JS01 per gram of feed (JS01 group); or de Man, Rogosa, and Sharpe liquid medium (control group) 35 days. Compared with JS01, BS15 significantly improved the daily weight gain and diarrhea index of the piglets. The BS15 group had higher fecal sIgA levels, whereas the JS01 group had high fecal sIgA levels only after 35 days of treatment. Additionally, BS15 altered T cell subsets in peripheral blood by significantly increasing the CD3⁺CD4⁺ T cell percentage and CD3⁺CD4⁺/CD3⁺CD8⁺ ratio and decreasing the CD3⁺CD8⁺ T cell percentage. Moreover, BS15 exerted better beneficial effects on fecal microbiota than JS01. Specifically, the BS15 group had markedly increased Clostridium, Peptococcus, and Lactobacillus populations on days 7 and 21 of treatment and reduced Escherichia coli populations on day 35 of treatment. These findings indicated that BS15 can be applied as a probiotic that promotes growth performance and controls diarrhea in piglets.

Bio-therapeutics from human milk: prospects and perspectives

Human milk is elixir for neonates and is a rich source of nutrients and beneficial microbiota required for infant growth and development. Its benefits prompted research into probing the milk components and their use as prophylactic or therapeutic agents. Culture-independent estimation of milk microbiome and high-resolution identification of milk components provide information, but a holistic purview of these research domains is lacking. Here, we review the current research on bio-therapeutic components of milk and simplified future directions for its efficient usage. Publicly available databases such as PubMed and Google scholar were searched for keywords such as probiotics and prebiotics related to human milk, microbiome and milk oligosaccharides. This was further manually curated for inclusion and exclusion criteria relevant to human milk and clinical efficacy. The literature was classified into subgroups and then discussed in detail to facilitate understanding. Although milk research is still in infancy, it is clear that human milk has many functions including protection of infants by passive immunization through secreted antibodies, and transfer of immune regulators, cytokines and bioactive peptides. Unbiased estimates show that the human milk carries a complex community of microbiota which serves as the initial inoculum for establishment of infant gut. Our search effectively screened for evidence that shows that milk also harbours many types of prebiotics such as human milk oligosaccharides which encourage growth of beneficial probiotics. The milk also trains the naive immune system of the infant by supplying immune cells and stimulatory factors, thereby strengthening mucosal and systemic immune system. Our systematic review would improve understanding of human milk and the inherent complexity and diversity of human milk. The interrelated functional role of human milk components especially the oligosaccharides and microbiome has been discussed which plays important role in human health.

Postbiotics-parabiotics: the new horizons in microbial biotherapy and functional foods

Probiotics have several health benefits by modulating gut microbiome; however, techno-functional limitations such as viability controls have hampered their full potential applications in the food and pharmaceutical sectors. Therefore, the focus is gradually shifting from viable probiotic bacteria towards non-viable paraprobiotics and/or probiotics derived biomolecules, so-called postbiotics. Paraprobiotics and postbiotics are the emerging concepts in the functional foods field because they impart an array of health-promoting properties. Although, these terms are not well defined, however, for time being these terms have been defined as here. The postbiotics are the complex mixture of metabolic products secreted by probiotics in cell-free supernatants such as enzymes, secreted proteins, short chain fatty acids, vitamins, secreted biosurfactants, amino acids, peptides, organic acids, etc. While, the paraprobiotics are the inactivated microbial cells of probiotics (intact or ruptured containing cell components such as peptidoglycans, teichoic acids, surface proteins, etc.) or crude cell extracts (i.e. with complex chemical composition)". However, in many instances postbiotics have been used for whole category of postbiotics and parabiotics. These elicit several advantages over probiotics like; (i) availability in their pure form, (ii) ease in production and storage, (iii) availability of production process for industrial-scale-up, (iv) specific mechanism of action, (v) better accessibility of Microbes Associated Molecular Pattern (MAMP) during recognition and interaction with Pattern Recognition Receptors (PRR) and (vi) more likely to trigger only the targeted responses by specific ligand-receptor interactions. The current review comprehensively summarizes and discussed various methodologies implied to extract, purify, and identification of paraprobiotic and postbiotic compounds and their potential health benefits.

Characterization of Riboflavin-Producing Strains of Lactobacillus plantarum as Potential Probiotic Candidate through in vitro Assessment and Principal Component Analysis

Lactic acid bacteria (LAB) are known for their probiotic properties, but only a few strains produce riboflavin. We evaluated the probiotic properties of four riboflavin-producing strains of Lactobacillus plantarum (BBC33, BBC32A, BIF43, and BBC32B) by using in vitro assessment and carried out multivariate principal component analysis (PCA) to select the best strain. Safety, antioxidant, and exopolysaccharide-producing properties were also studied. Lact. plantarum BBC33 showed better probiotic potential, followed by strain BIF43. Lact. plantarum BBC32A degraded mucin and excluded as a potential probiotic candidate. Lact. plantarum BIF43, BBC33, and BBC32A tolerated simulated gastrointestinal conditions and their overnight cell-free culture supernatants (CFSs, pH 4.0-4.3) inhibited the growth of Escherichia coli AF10, Salmonella Typhi MTCC98, Bacillus cereus NCDC250, and Pseudomonas aeruginosa NCDC105. Lact. plantarum BIF43 and BBC33 did not degrade mucin, adhered to human epithelial colorectal adenocarcinoma Caco-2 cells (22-25%), and aggregated with indicators (30-50%). Moreover, both were non-hemolytic and sensitive to most antibiotics tested. Of the two selected strains, BIF43 showed better exopolysaccharides (EPS) producing phenotype. The CFSs of all strains showed high (85-93%) 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. PCA confirmed the results obtained from in vitro probiotic experiments and supported the selection of Lact. plantarum BIF33 and BBC43, as potential probiotics.

Novel Pathway for Corrinoid Compounds Production in Lactobacillus

Vitamin B₁₂ or cobalamin is an essential metabolite for humans, which makes it an interesting compound for many research groups that focus in different producer-strains synthesis pathways. In this work, we report the influence of key intermediaries for cobalamin synthesis added to the culture medium in two Lactobacillus (L.) strains, L. reuteri CRL 1098 and L. coryniformis CRL 1001. Here, we report that addition of Co²⁺ and 5,6-dimethylbenzimidazole increased the corrinoid compounds production in both strains while addition of L-threonine increased only the corrinoid compounds production by CRL 1001 strain. Then, we purified and characterized by LC-MS the corrinoid compounds obtained. Physiological studies besides in silico analysis revealed that L. reuteri CRL 1098 and L. coryniformis CRL 1001 follow different pathways for the last steps of the corrinoid compounds synthesis.

Conjugated linoleic acid enriched skim milk prepared with Lactobacillus fermentum DDHI27 endorsed antiobesity in mice

Aim: This study evaluated the antiobesity effect of skim milk prepared with conjugated linoleic acid producing probiotic Lactobacillus fermentum DDHI27 (PCLA). Materials & methods: C57BL/6 J mice were divided into five groups, and different obesity-associated parameters were studied. Results: PCLA supplementation alleviated body weight, epididymal and mesenteric fats and improves lipid profiles. Significant ameliorations in leptin, blood glucose, hepatic steatosis and reduction in adipocytes size were also observed. Additionally, feeding also led to positive alterations in the adipogenesis transcription factors and key lipogenesis genes. Improvement in the gut microbiota dysbiosis was also revealed. Conclusion: Results inferred that PCLA exerted an antiobesity effect in diet-induced obese mice and may be further developed in the functional foods for the management of obesity.

Harnessing the Power of Microbiome Assessment Tools as Part of Neuroprotective Nutrition and Lifestyle Medicine Interventions

An extensive body of evidence documents the importance of the gut microbiome both in health and in a variety of human diseases. Cell and animal studies describing this relationship abound, whilst clinical studies exploring the associations between changes in gut microbiota and the corresponding metabolites with neurodegeneration in the human brain have only begun to emerge more recently. Further, the findings of such studies are often difficult to translate into simple clinical applications that result in measurable health outcomes. The purpose of this paper is to appraise the literature on a select set of faecal biomarkers from a clinician’s perspective. This practical review aims to examine key physiological processes that influence both gastrointestinal, as well as brain health, and to discuss how tools such as the characterisation of commensal bacteria, the identification of potential opportunistic, pathogenic and parasitic organisms and the quantification of gut microbiome biomarkers and metabolites can help inform clinical decisions of nutrition and lifestyle medicine practitioners.

Bio-prospectus of cadmium bioadsorption by lactic acid bacteria to mitigate health and environmental impacts

Foodstuffs and water are the key sources of cadmium biomagnifiaction. The available strategies to mitigate this problem are unproductive and expensive for practical large-scale use. Biological decontamination of metals through environmental microbes has been known since long time, whereas lactic acid bacteria (LAB) have not been extensively studied for this purpose. The LAB are known for maintaining homeostasis and suppression of pathogens in humans and animals. They also play a vital role in bioremediation of certain heavy metals. Recently in-vivo research findings strongly complement the in-vitro results in relation to decreased total body cadmium burden in animal model. This review summarizes the currently available information on impact of toxic metal (Cd) on human and animal health as well as cadmium sequestration through microbes placed broadly, whereas preeminent attention grabbed on LAB-cadmium interaction to explore their possible role in bioremediation of cadmium from foods and environment to safeguard human as well as environment health.

Techno-functional differentiation of two vitamin B12 producing Lactobacillus plantarum strains: an elucidation for diverse future use

An appropriate selection of Lactobacillus strain (probiotic/starter/functional) on the basis of its techno-functional characteristics is required before developing a novel fermented functional food. We compared vitamin B₁₂ (B₁₂, cobalamin) producing Lactobacillus plantarum isolates, BHM10 and BCF20, for functional (vitamin over-production, genomic insight to B₁₂ structural genes, and probiotic attributes) and technological [milks (skim and soy) fermentation and B₁₂ bio-fortification] characteristics. Addition of B₁₂ precursors (5-amonolevulinate and dimethylbenzimidazole) to cobalamin-free fermentation medium increased vitamin production in BHM10, BCF20, and DSM20016 (a positive standard) by 3.4-, 4.4-, and 3.86-folds, respectively. Three important B₁₂ structural genes were detected in L. plantarum species (strains BHM10 and BCF20) by PCR for the first time. The gene sequences were submitted to NCBI GenBank and found phylogenetically closer to respective sequences in B₁₂ producing Lactobacillus reuteri strains. During comparative probiotic testing, BCF20 showed significantly higher (p < 0.05 to p < 0.001) gastrointestinal tolerance and cell surface hydrophobicity (p < 0.05) than BHM10. Moreover, only BCF20 was found positive for BSH activity and also exhibited comparatively better antagonistic potential against potent pathogens. Conversely, high acid and bile susceptible strain BHM10 displayed significantly higher soy milk fermentation and resultant B₁₂ bio-fortification abilities during technological testing. Two B₁₂ quantification techniques, UFLC and competitive immunoassay, confirmed the in vitro and in situ bio-production of bio-available form of B₁₂ after BHM10 fermentation. Conclusively, techno-functional differentiation of two B₁₂ producing strains elucidates their diverse future use; BCF20 either for B₁₂ over-production (in vitro) or as a probiotic candidate, while BHM10 for cobalamin bio-fortification (in situ) in soy milk.