Enhancing vitamin B12 content in soy-yogurt by Lactobacillus reuteri

Biological properties of vitamin B12

Vitamin B12, cobalamin, is indispensable for humans owing to its participation in two biochemical reactions: the conversion of l-methylmalonyl coenzyme A to succinyl coenzyme A, and the formation of methionine by methylation of homocysteine. Eukaryotes, encompassing plants, fungi, animals and humans, do not synthesise vitamin B12, in contrast to prokaryotes. Humans must consume it in their diet. The most important sources include meat, milk and dairy products, fish, shellfish and eggs. Due to this, vegetarians are at risk to develop a vitamin B12 deficiency and it is recommended that they consume fortified food. Vitamin B12 behaves differently to most vitamins of the B complex in several aspects, e.g. it is more stable, has a very specific mechanism of absorption and is stored in large amounts in the organism. This review summarises all its biological aspects (including its structure and natural sources as well as its stability in food, pharmacokinetics and physiological function) as well as causes, symptoms, diagnosis (with a summary of analytical methods for its measurement), prevention and treatment of its deficiency, and its pharmacological use and potential toxicity.

Probiotics and the microbiota-gut-brain axis in neurodegeneration: Beneficial effects and mechanistic insights

Neurodegenerative diseases (NDs) are a group of heterogeneous disorders with a high socioeconomic burden. Although pharmacotherapy is currently the principal therapeutic approach for the management of NDs, mounting evidence supports the notion that the protracted application of available drugs would abate their dopaminergic outcomes in the long run. The therapeutic application of microbiome-based modalities has received escalating attention in biomedical works. In-depth investigations of the bidirectional communication between the microbiome in the gut and the brain offer a multitude of targets for the treatment of NDs or maximizing the patient's quality of life. Probiotic administration is a well-known microbial-oriented approach to modulate the gut microbiota and potentially influence the process of neurodegeneration. Of note, there is a strong need for further investigation to map out the mechanistic prospects for the gut-brain axis and the clinical efficacy of probiotics. In this review, we discuss the importance of microbiome modulation and hemostasis via probiotics, prebiotics, postbiotics and synbiotics in ameliorating pathological neurodegenerative events. Also, we meticulously describe the underlying mechanism of action of probiotics and their metabolites on the gut-brain axis in different NDs. We suppose that the present work will provide a functional direction for the use of probiotic-based modalities in promoting current practical treatments for the management of neurodegenerative-related diseases.

Characterization of a symbiotic beverage based on water-soluble soybean extract fermented by Lactiplantibacillus plantarum ATCC 8014

The health benefits of functional foods are associated with consumer interest and have supported the growth of the market for these types of foods, with emphasis on the development of new formulations based on plant extracts. Therefore, the present study aimed to characterize a symbiotic preparation based on water-soluble soy extract, supplemented with inulin and xylitol and fermented by Lactiplantibacillus plantarum ATCC 8014. Regarding nutritional issues, the symbiotic formulation can be considered a source of fiber (2 g/100 mL) and proteins (2.6 g/100 mL), and it also has a low-fat content and low caloric value. This formulation, in terms of microbiological aspects, remained adequate to legal standards after storage for 60 days under refrigeration and also presented an adequate quantity of the aforementioned probiotic strain, corresponding to 9.11 Log CFU.mL-1. These viable L. plantarum cells proved to be resistant to simulated human gastrointestinal tract conditions, reaching the intestine at high cell concentrations of 7.95 Log CFU.mL-1 after 60 days of refrigeration. Regarding sensory evaluation, the formulation showed good acceptance, presenting an average overall impression score of 6.98, 5.98, and 5.16, for control samples stored for 30 and 60 days under refrigeration, respectively. These results demonstrate that water-soluble soy extract is a suitable matrix for fermentation involving L. plantarum ATCC 8014, supporting and providing data on the first steps towards the development of a symbiotic functional food, targeting consumers who have restrictions regarding the consumption of products of animal origin, diabetics, and individuals under calorie restrictions.

Characterisation of Indian gut microbiome for B-vitamin production and its comparison with Chinese cohort

The human gut microbiota can biosynthesize essential micronutrients such as B-vitamins and is also known for its metabolic cooperative behaviour. The present study characterises such B-vitamin biosynthesizers, their biosynthetic pathways, explores their prevalence and abundance, examines how lifestyle or diet affects them in multiple Indian cohorts and compares it with the Chinese cohort. To achieve this, publicly available faecal metagenome data of healthy individuals from multiple Indian (two urban and three tribal populations) and a Chinese cohort were analysed. The distribution of prevalence and abundance of B-vitamin biosynthesizers showed similar profiles to that of the entire gut community of the Indian cohort, and there were 28 B-vitamin biosynthesizers that had modest or higher prevalence and abundance. The omnivorous diet affected only the prevalence of a few B-vitamin biosynthesizers; however, lifestyle and/or location affected both prevalence and abundance. A comparison with the Chinese cohort showed that fourteen B-vitamin biosynthesizers were significantly more prevalent and abundant in Chinese as compared with Indian samples (False Discovery Rate (FDR) <= 0·05). The metabolic potential of the entire gut community for B-vitamin production showed that within India, the tribal cohort has a higher abundance of B-vitamin biosynthesis pathways as compared with two urban cohorts namely, Bhopal and Kasargod, and comparison with the Chinese cohort revealed a higher abundance in the latter group. Potential metabolic cooperative behaviour of the Indian gut microbiome for biosynthesis of the B-vitamins showed multiple pairs of species showed theoretical complementarity for complete biosynthetic pathways genes of thiamine, riboflavin, niacin and pantothenate.

Enhancing the functionality of plant-based Yogurt: Integration of lycopene through dual-stage fermentation of soymilk

Well-defined compositional assemblies of plant-based yogurt are of fast-growing awareness for world population concerning environmental sustainability, economic burdens and health risks. Soybean is an attractive candidate for plant yogurt, suffering from poor flavor, limited nutrition, and undesired allergens to offer healthy-functional segments. Herein, we deciphered a novel lycopene-soy yogurt by efficient two-stage fermentation of engineered B. subtilis and LAB. The fortified sogurt was ensured with redundant lycopene of 22.67 ± 2.95 mg/g DCW by engineered B. subtilis and enriched soy isoflavone from synergistic effects of engineered B. subtilis and LAB, possessing strong antioxidant capacity for upgrading functionality. Moreover, the desired pH, accelerated protein hydrolysis, enhanced amino acid availability, and expected sensory attributes cooperatively conferred lycopene-soy yogurt as healthy functional food. High potential is firstly ascribed to sequential dual culture of engineered B. subtilis and LAB in lycopene-soy yogurt, in which flavorful, hypoallergenic and antioxidative ingredients enabled functionalities for plant-based yogurt.

Lactobacilli and Klebsiella: Two Opposites in the Fight for Human Health

The problem of antibiotic resistance is currently very acute. Numerous research and development of new antibacterial drugs are being carried out that could help cope with various infectious agents. One of the promising directions for the search for new antibacterial drugs is the search among the probiotic strains present in the human gastrointestinal tract. This review is devoted to characteristics of one of these probiotic strains that have been studied to date: Limosilactobacillus reuteri. The review discusses its properties, synthesis of various compounds, as well as role of this strain in modulating various systems of the human body. The review also examines key characteristics of one of the most harmful among the currently known pathogenic organisms, Klebsiella, which is significantly resistant to antibiotics existing in medical practice, and also poses a great threat of nosocomial infections. Discussion of characteristics of the two strains, which have opposite effects on human health, may help in creation of new effective antibacterial drugs without significant side effects.

Fermented foods and beverages: a potential in situ vitamin B12 biofortification - a literature review

Millions of dollars have been increasingly spent on plant-based diets. Considering that vitamin B12 is obtained from the consumption of animal-derived foods, new sources of vitamin B12 and methods of food fortification are being eagerly sought. Therefore, this work aims to evaluate advances in situ fermentation processes of food and beverages produced on a large scale and industrial applications for obtaining cobalamin-rich products. Bibliometric analysis was performed and revealed that several studies report a great capacity for in situ biofortification of B12 in foods, mostly on the use of propionic (PB) and lactic (LAB) bacteria. In this context, market potentials for such products, the main microorganisms, including simultaneous cultures, and their respective applications have been presented herein. Although knowledge on potential applications is still limited, field research has been increasingly conducted, thus revealing scientific and technological opportunities, both for the production and the stability of B12 found in plant-based foods.

B-vitamins and heat processed fermented starchy and vegetable foods in sub-Saharan Africa: A review

Micronutrient deficiency still occurs in sub-Saharan Africa (SSA) despite the availability of several food resources, particularly fermented foods and vegetables, with high nutritional potential. Fermentation enhances the quality of food in several aspects. Organoleptically, certain taste, aroma, and textures are developed. Health and safety are improved by inhibiting the growth of several foodborne pathogens and removing harmful toxic compounds. Furthermore, nutrition is enhanced by improving micronutrient contents and bioavailability from the food, especially vitamin B content. However, during processing and before final consumption, many fermented foods are heat treated (drying, pasteurization, cooking, etc.) to make the food digestible and safe for consumption. Heat treatment improves the bioavailability of B-vitamins in some foods. In other foods, heating decreases the nutritional value because some B-vitamins are degraded. In SSA, cooked starchy foods are often associated with vegetables in household meals. This paper reviews studies that have focused fermented starchy foods and vegetable foods in SSA with the potential to provide B-vitamins to consumers. The review also describes the process of the preparation of these foods for final consumption, and techniques that can prevent or lessen B-vitamin loss, or enrich B-vitamins prior to consumption.

Vitamin B12 produced by Cetobacterium somerae improves host resistance against pathogen infection through strengthening the interactions within gut microbiota

BACKGROUND

Pathogen infections seriously affect host health, and the use of antibiotics increases the risk of the emergence of drug-resistant bacteria and also increases environmental and health safety risks. Probiotics have received much attention for their excellent ability to prevent pathogen infections. Particularly, explaining mechanism of action of probiotics against pathogen infections is important for more efficient and rational use of probiotics and the maintenance of host health.

RESULTS

Here, we describe the impacts of probiotic on host resistance to pathogen infections. Our findings revealed that (I) the protective effect of oral supplementation with B. velezensis against Aeromonas hydrophila infection was dependent on gut microbiota, specially the anaerobic indigenous gut microbe Cetobacterium; (II) Cetobacterium was a sensor of health, especially for fish infected with pathogenic bacteria; (III) the genome resolved the ability of Cetobacterium somerae CS2105-BJ to synthesize vitamin B12 de novo, while in vivo and in vitro metabolism assays also showed the ability of Cetobacterium somerae CS2105-BJ to produce vitamin B12; (IV) the addition of vitamin B12 significantly altered the gut redox status and the gut microbiome structure and function, and then improved the stability of the gut microbial ecological network, and enhanced the gut barrier tight junctions to prevent the pathogen infection.

CONCLUSION

Collectively, this study found that the effect of probiotics in enhancing host resistance to pathogen infections depended on function of B12 produced by an anaerobic indigenous gut microbe, Cetobacterium. Furthermore, as a gut microbial regulator, B12 exhibited the ability to strengthen the interactions within gut microbiota and gut barrier tight junctions, thereby improving host resistance against pathogen infection. Video Abstract.

Methylotrophic bacteria with cobalamin-dependent mutases in primary metabolism as potential strains for vitamin B12 production

Several bacterial species are known for their ability to synthesize vitamin B12 but biotechnological vitamin B12 production today is restricted to Pseudomonas denitrificans and Propionibacterium freudenreichii. Nevertheless, the rising popularity of veganism leads to a growing demand for vitamin B12 and thereby interest in alternative strains which can be used as efficient vitamin B12 sources. In this work, we demonstrate that methylotrophic microorganisms which utilize the ethylmalonyl-CoA pathway containing B12-dependent enzymes are capable of active vitamin B12 production. Several bacteria with an essential function of the pathway were tested for vitamin B12 synthesis. Among the identified strains, Hyphomicrobium sp. DSM3646 demonstrated the highest vitamin B12 levels reaching up to 17.9 ± 5.05 µg per g dry cell weight. These relatively high vitamin B12 concentrations achieved in simple cultivation experiments were performed in a mineral methanol medium, which makes Hyphomicrobium sp. DSM3646 a new promising cobalamin-producing strain.

Intermediate role of gut microbiota in vitamin B nutrition and its influences on human health

Vitamin B consists of a group of water-soluble micronutrients that are mainly derived from the daily diet. They serve as cofactors, mediating multiple metabolic pathways in humans. As an integrated part of human health, gut microbiota could produce, consume, and even compete for vitamin B with the host. The interplay between gut microbiota and the host might be a crucial factor affecting the absorbing processes of vitamin B. On the other hand, vitamin B supplementation or deficiency might impact the growth of specific bacteria, resulting in changes in the composition and function of gut microbiota. Together, the interplay between vitamin B and gut microbiota might systemically contribute to human health. In this review, we summarized the interactions between vitamin B and gut microbiota and tried to reveal the underlying mechanism so that we can have a better understanding of its role in human health.

Bioprocess Strategies for Vitamin B12 Production by Microbial Fermentation and Its Market Applications

Vitamin B₁₂ is a widely used compound in the feed and food, healthcare and medical industries that can only be produced by fermentation because of the complexity of its chemical synthesis. For this reason, finding better producer strains and optimizing their bioprocesses have been the main focus of industrial producers over the last few decades. In this review, we initially provide a historical overview of vitamin B₁₂ research and the main biosynthetic characteristics of the two microorganism families typically used for its industrial production: several strains of Propionibacterium freudenreichii and strains related to Pseudomonas denitrificans. Later, a complete summary of the current state of vitamin B₁₂ industrial production as well as the main advances and challenges for improving it is detailed, with a special focus on bioprocess optimization, which aims not only to increase production but also sustainability. In addition, a comprehensive list of the most important and relevant patents for the present industrial strains is provided. Finally, the potential applications of vitamin B₁₂ in different markets are discussed.

Lentil-Based Yogurt Alternatives Fermented with Multifunctional Strains of Lactic Acid Bacteria-Techno-Functional, Microbiological, and Sensory Characteristics

A milk-alternative produced from lentil protein isolate was fermented with three multifunctional strains of lactic acid bacteria, Leuconostoc citreum TR116, Leuconostoc pseudomesenteroides MP070, and Lacticaseibacillus paracasei FST 6.1. As a control, a commercial starter culture containing Streptococcus thermophilus was used. The metabolic performance of these strains and the techno-functional properties of the resulting yogurt alternatives (YA) were studied. Microbial growth was evaluated by cell counts, acidification, and carbohydrate metabolization. The structure of the YA was investigated by textural and rheological analyses and confocal laser scanning microscopy (CLSM). Production of antifungal compounds, the influence of fermentation on the content of FODMAPs, and typical metabolites were analyzed, and a sensory analysis was performed. The results revealed an exponential microbial growth in the lentil base substrate supported by typical acidification, which indicates a suitable environment for the selected strains. The resulting YA showed a gel-like texture typical for non-stirred yogurts, and high water holding capacity. The tested strains produced much higher levels of antifungal phenolic compounds than the commercial control and are therefore promising candidates as adjunct cultures for shelf-life extension. The Leuconostoc strains produced mannitol from fructose and could thus be applied in sugar-reduced YA. Preliminary sensory analysis showed high acceptance for YA produced with Lacticaseibacillus paracasei FST 6.1, and a yogurt-like flavor not statistically different to that produced by the control. Overall, each tested strain possessed promising functionalities with great potential for application in fermented plant-based dairy-alternatives.

B Vitamins and Their Roles in Gut Health

B vitamins act as coenzymes in a myriad of cellular reactions. These include energy production, methyl donor generation, neurotransmitter synthesis, and immune functions. Due to the ubiquitous roles of these vitamins, their deficiencies significantly affect the host’s metabolism. Recently, novel roles of B vitamins in the homeostasis of gut microbial ecology and intestinal health continue to be unravelled. This review focuses on the functional roles and biosynthesis of B vitamins and how these vitamins influence the growth and proliferation of the gut microbiota. We have identified the gut bacteria that can produce vitamins, and their biosynthetic mechanisms are presented. The effects of B vitamin deficiencies on intestinal morphology, inflammation, and its effects on intestinal disorders are also discussed.

Current trends in the development of soy-based foods containing probiotics and paving the path for soy-synbiotics

In the world of highly processed foods, special attention is drawn to the nutrient composition and safety of consumed food products. Foods fortified with probiotic bacteria confer beneficial effects on human health and are categorized as functional foods. The salubrious activities of probiotics include the synthesis of vital bioactives, prevention of inflammatory diseases, anticancerous, hypocholesterolemic, and antidiarrheal effects. Soy foods are exemplary delivery vehicles for probiotics and prebiotics and there are diverse strategies to enhance their functionality like employing mixed culture fermentation, engineering probiotics, and incorporating prebiotics in fermented soy foods. High potential is ascribed to the concurrent use of probiotics and prebiotics in one product, termed as "synbiotics," which implicates synergy, in which a prebiotic ingredient particularly favors the growth and activity of a probiotic micro-organism. The insights on emended bioactive profile, metabolic role, and potential health benefits of advanced soy-based probiotic and synbiotic hold a promise which can be profitably implemented to meet consumer needs. This article reviews the available knowledge about strategies to enhance the nutraceutical potential, mechanisms, and health-promoting effects of advanced soy-based probiotics. Traditional fermentation merged with diverse strategies to improve the efficiency and health benefits of probiotics considered vital, are also discussed.

Vitamin B12 sources in non-animal foods: a systematic review

Interest in plant-based diets and vegetarianism is increasing worldwide, however, a concern for total vegetarians is vitamin B12 (B12) deficiency. We conducted a systematic review to investigate non-animal food sources of B12. Databases were PubMed, LILACS, Cochrane, Embase and Google Scholar, up to September 9, 2020. Quality of the eligible studies were assessed. We identified 25 studies which assessed B12 content in seaweeds, mushrooms, plants and fermented foods. Initial studies were microbiological bioassay, ELISA and HPLC. In the last decade, more sensitive method for real B12 determination was used, the liquid chromatography-electrospray ionization tandem mass spectrometry chromatograms. Real B12 content varied from mean (SD) mcg/portion size of seaweed hijiki 3 × 10-3/7 g to nori 1.03 - 2.68/sheet; mushroom white button cap 2 × 10-3(7 × 10-4)/20 g dry weight (dw) to shiitake 0.79(0.67)-1.12 (0.78)/20 g dw; and fermented foods from soy yogurt 20/cup. It is possible that daily recommendations for B12 can be met by a varied diet containing non-animal B12 food sources. Future research should consider different methods of storage, preparation, fermented foods and standardization of the production of certain foods.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2053057.

Functional bacterial cultures for dairy applications: towards improving safety, quality, nutritional and health benefit aspects

Traditionally, fermentation was used to preserve the shelf life of food. Currently, in addition to favouring food preservation, well standardized and controlled industrial processes are also aimed at improving the functional characteristics of the final product. In this regard, starter cultures have become an essential cornerstone of food production. The selection of robust microorganisms, well adapted to the food environment, has been followed by the development of microbial consortia that provide some functional characteristics, beyond their acidifying capacity, achieving safer, high‐quality foods with improved nutritional and health‐promoting properties. In addition to starters, adjunct cultures and probiotics, which normally do not have a relevant role in fermentation, are added to the food in order to provide some beneficial characteristics. This review focuses on highlighting the functional characteristics of food starters, as well as adjunct and probiotic cultures (mainly lactic acid bacteria and bifidobacteria), with a specific focus on the synthesis of metabolites for preservation and safety aspects (e.g. bacteriocins), organoleptic properties (e.g. exopolysaccharides), nutritional (e.g. vitamins) and health improvement (e.g. neuroactive molecules). Literature reporting the application of these functional cultures in the manufacture of foods, mainly those related to dairy production, such as cheeses and fermented milks, has also been updated.

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.

Challenges associated with spray drying of lactic acid bacteria: Understanding cell viability loss

Lactic acid bacteria (LAB) cultures used in food fermentation are often dried to reduce transportation costs and facilitate handling during use. Dried LAB ferments are generally lyophilized to ensure high cell viability. Spray drying has come to the forefront as a promising technique due to its versatility and lower associated energy costs. Adverse conditions during spray drying, such as mechanical stress, dehydration, heating, and oxygen exposure, can lead to low LAB cell viability. This reduced viability has limited spray drying's industrial applications thus far. This review aims to demonstrate the operations and thermodynamic principles that govern spray drying, then correlate them to the damage suffered by LAB cells during the spray-drying process. The particularities of spray drying that might cause LAB cell death are detailed in this review, and the conclusion may enhance future studies on ways to improve cell viability.

Role of Probiotic Bacilli in Developing Synbiotic Food: Challenges and Opportunities

The human body is inhabited by a vast diversity of probiotic microorganisms that could positively affect human physiology. Besides, prebiotic food substances may induce symbiotic relationship among probiotic species through the successful establishment of commensal microbiota, whose connections with the host are multifaceted and multidirectional. As deliberated throughout this review, prebiotic and synbiotic foods contain the capability to stimulate numerous health characteristics in host organisms through various means. Predominantly, the normal microbiota fosters the digestion of food and may boost the innate and adaptive immune system’s functionalities. Therefore, live probiotic bacteria, for instance, probiotic Bacilli obtained together with prebiotic food, can help stimulate healthiness in humans. Thus, we discuss how certain dietary fibers may preserve the probiotic efficacy by serving as the scaffold for probiotic Bacilli to colonize them through forming symbiotic interactions. The fibers can essentially promote protection by encapsulating probiotic Bacilli against various environmental and physical stresses that might kill the free-living bacterial cells. Besides, these fibers would serve as prebiotic substances that would eventually be utilized for the proliferation of probiotic cells. It is believed that applying this conceptual idea will provide a novel platform toward developing probiotic and synbiotic foods, as discussed in this review.

Microbiota Changes in Fathers Consuming a High Prebiotic Fiber Diet Have Minimal Effects on Male and Female Offspring in Rats

BACKGROUND

Consuming a diet high in prebiotic fiber has been associated with improved metabolic and gut microbial parameters intergenerationally, although studies have been limited to maternal intake with no studies examining this effect in a paternal model.

METHOD

Male Sprague Dawley rats were allocated to either (1) control or (2) oligofructose-supplemented diet for nine weeks and then mated. Offspring consumed control diet until 16 weeks of age. Bodyweight, body composition, glycemia, hepatic triglycerides, gastrointestinal hormones, and gut microbiota composition were measured in fathers and offspring.

RESULTS

Paternal energy intake was reduced, while satiety inducing peptide tyrosine tyrosine (PYY) gut hormone was increased in prebiotic versus control fathers. Increased serum PYY persisted in female prebiotic adult offspring. Hepatic triglycerides were decreased in prebiotic fathers with a similar trend (p = 0.07) seen in female offspring. Gut microbial composition showed significantly reduced alpha diversity in prebiotic fathers at 9 and 12 weeks of age (p < 0.001), as well as concurrent differences in beta diversity (p < 0.001), characterized by differences in Bifidobacteriaceae, Lactobacillaceae and Erysipelotrichaceae, and particularly Bifidobacterium animalis. Female prebiotic offspring had higher alpha diversity at 3 and 9 weeks of age (p < 0.002) and differences in beta diversity at 15 weeks of age (p = 0.04). Increases in Bacteroidetes in female offspring and Christensenellaceae in male offspring were seen at nine weeks of age.

CONCLUSIONS

Although paternal prebiotic intake before conception improves metabolic and microbiota outcomes in fathers, effects on offspring were limited with increased serum satiety hormone levels and changes to only select gut bacteria.

Isolation, identification, and selection of strains as candidate probiotics and starters for fermentation of Swedish legumes

BACKGROUND

The non-dairy sector is growing, fermented alternatives to dairy are sparse. Adapted starter cultures to substituting raw materials needs to be developed.

OBJECTIVE

Aims of this study were to isolate, identify, and phenotypically characterize lactic acid bacteria (LAB) that inhabit Swedish legumes, and assess properties necessary for selecting strains with the ability to ferment a bean beverage and with potential health beneficial properties.

DESIGN

Isolates of presumed LAB were obtained from legumes collected at Öland, Sweden. Strain diversity was assessed by repetitive polymerase chain reaction (rep-PCR). The strains were identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Species belonging to Enterococcus were predominant along with Pediococcus and closely related Bacillus. Strains were tested for tolerance to low pH, phenol, and bile as well as their bile salt hydrolase (BSH) activity. In addition, Enterococcus strains were tested for antibiotic resistance, and Pediococcus strains for their ability to ferment a bean beverage.

RESULTS

From the 25 strains characterized, five were found resistant to low pH, bile, and phenol, suggesting that they can survive a passage through the gastrointestinal tract (GIT) and hence potentially exert beneficial effects in the host. These are suggested for further investigation on specific host-beneficial properties. Two of these, belonging to Pediococcus pentosaceus, were able to ferment a bean beverage without any added nutrients, indicating that the Pediococcus strains are well adapted to the bean substrate. One of the P. pentosaceus strains were also able to markedly improve the reduction of phytate by the phytase-producing yeast strain Pichia kudriavzevii TY1322 during co-fermentation as well as increase the final cell count of the yeast strain.

CONCLUSION

Strain isolation and characterization performed in this study aids in selecting starter cultures for legume fermentation. Nutritional properties can be improved by co-fermentation with yeast indicating that novel nutritious fermented non-dairy products could be developed.

Microalgal assimilation of vitamin B12 toward the production of a superfood

A network of components from different metabolic pathways is the building scaffold of an indispensable compound in the human organism-vitamin B₁₂ . The biosynthesis of this compound is restricted to a limited number of representatives of bacteria and archaea, while vitamin B₁₂ -dependent enzymes are spread through several domains of life. Different attempts have been performed to increase vitamin B₁₂ levels in dietary products, particularly in vegetarian and vegan dietary regimes. The integration of vitamin B₁₂ in microalgae through symbiosis with microorganisms generally recognized as safe, for example the probiotic Lactobacillus reuteri, can even increase the nutritional value of the microalgal biomass. This study reviews the microbial production of vitamin B₁₂ based on genetic analyses and chemical studies. Recent genetic approaches are focused, particularly potential metabolic engineering targets to increase vitamin B₁₂ production. The bioincorporation of vitamin B₁₂ in microalgae as an attempt to provide a superfood is also reviewed. PRACTICAL APPLICATIONS: Novel food habits (i.e., vegan lifestyle) may lack relevant nutrients, including vitamin B₁₂ . Therefore, there is an increased demand for dietary products rich in vitamin B₁₂ . Of potential interest is the provision of microbial-based superfood rich in numerous nutrients, including this vitamin. This manuscript provides an in-depth and timely overview on vitamin B₁₂ biosynthesis and the major advances on metabolic engineering for improved vitamin B₁₂ production by probiotic bacteria and other microorganisms generally recognized as safe. A relevant advance would result from the bioincorporation of vitamin B₁₂ in alternative microorganisms (non-vitamin B₁₂ producers) increasingly recognized as superfood, that is microalgae.

Metabolism of Dietary and Microbial Vitamin B Family in the Regulation of Host Immunity

Vitamins are micronutrients that have physiological effects on various biological responses, including host immunity. Therefore, vitamin deficiency leads to increased risk of developing infectious, allergic, and inflammatory diseases. Since B vitamins are synthesized by plants, yeasts, and bacteria, but not by mammals, mammals must acquire B vitamins from dietary or microbial sources, such as the intestinal microbiota. Similarly, some intestinal bacteria are unable to synthesize B vitamins and must acquire them from the host diet or from other intestinal bacteria for their growth and survival. This suggests that the composition and function of the intestinal microbiota may affect host B vitamin usage and, by extension, host immunity. Here, we review the immunological functions of B vitamins and their metabolism by intestinal bacteria with respect to the control of host immunity.

Stability of vitamin B12 with the protection of whey proteins and their effects on the gut microbiome

Cobalamin degrades in the presence of light and heat, which causes spectral changes and loss of coenzyme activity. In the presence of beta-lactoglobulin or alpha-lactalbumin, the thermal- and photostabilities of adenosylcobalamin (ADCBL) and cyanocobalamin (CNCBL) are increased by 10-30%. Similarly, the stabilities of ADCBL and CNCBL are increased in the presence of whey proteins by 19.7% and 2.2%, respectively, when tested in gastric juice for 2 h. Due to the limited absorption of cobalamin during digestion, excess cobalamin can enter the colon and modulate the gut microbiome. In a colonic model in vitro, supplementation with cobalamin and whey enhanced the proportions of Firmicutes and Bacteroidetes spp. and reduced those of Proteobacteria spp., which includes pathogens such as Escherichia and Shigella spp., and Pseudomonas spp. Thus, while complex formation could improve the stability and bioavailability of cobalamin, these complexes might also mediate gut microecology to influence human nutrition and health.

Role of Lactobacillus reuteri in Human Health and Diseases

Lactobacillus reuteri (L. reuteri) is a well-studied probiotic bacterium that can colonize a large number of mammals. In humans, L. reuteri is found in different body sites, including the gastrointestinal tract, urinary tract, skin, and breast milk. The abundance of L. reuteri varies among different individuals. Several beneficial effects of L. reuteri have been noted. First, L. reuteri can produce antimicrobial molecules, such as organic acids, ethanol, and reuterin. Due to its antimicrobial activity, L. reuteri is able to inhibit the colonization of pathogenic microbes and remodel the commensal microbiota composition in the host. Second, L. reuteri can benefit the host immune system. For instance, some L. reuteri strains can reduce the production of pro-inflammatory cytokines while promoting regulatory T cell development and function. Third, bearing the ability to strengthen the intestinal barrier, the colonization of L. reuteri may decrease the microbial translocation from the gut lumen to the tissues. Microbial translocation across the intestinal epithelium has been hypothesized as an initiator of inflammation. Therefore, inflammatory diseases, including those located in the gut as well as in remote tissues, may be ameliorated by increasing the colonization of L. reuteri. Notably, the decrease in the abundance of L. reuteri in humans in the past decades is correlated with an increase in the incidences of inflammatory diseases over the same period of time. Direct supplementation or prebiotic modulation of L. reuteri may be an attractive preventive and/or therapeutic avenue against inflammatory diseases.

In situ production of active vitamin B12 in cereal matrices using Propionibacterium freudenreichii

The in situ production of active vitamin B12 was investigated in aqueous cereal‐based matrices with three strains of food‐grade Propionibacterium freudenreichii. Matrices prepared from malted barley flour (33% w/v; BM), barley flour (6%; BF), and wheat aleurone (15%; AM) were fermented. The effect of cobalt and the lower ligand 5,6‐dimethylbenzimidazole (DMBI) or its natural precursors (riboflavin and nicotinamide) on active B12 production was evaluated. Active B12 production was confirmed by UHPLC–UV–MS analysis. A B12 content of 12–37 μg·kg⁻¹ was produced in BM; this content increased 10‐fold with cobalt and reached 940–1,480 μg·kg⁻¹ with both cobalt and DMBI. With riboflavin and nicotinamide, B12 production in cobalt‐supplemented BM increased to 712 μg·kg⁻¹. Approximately, 10 μg·kg⁻¹ was achieved in BF and AM and was increased to 80 μg·kg⁻¹ in BF and 260 μg·kg⁻¹ in AM with cobalt and DMBI. The UHPLC and microbiological assay (MBA) results agreed when both cobalt and DMBI or riboflavin and nicotinamide were supplemented. However, MBA gave ca. 20%–40% higher results in BM and AM supplemented with cobalt, indicating the presence of human inactive analogues, such as pseudovitamin B12. This study demonstrates that cereal products can be naturally fortified with active B12 to a nutritionally relevant level by fermenting with P. freudenreichii.

Effects of Probiotics, Prebiotics, and Synbiotics on Human Health

The human gastrointestinal tract is colonised by a complex ecosystem of microorganisms. Intestinal bacteria are not only commensal, but they also undergo a synbiotic co-evolution along with their host. Beneficial intestinal bacteria have numerous and important functions, e.g., they produce various nutrients for their host, prevent infections caused by intestinal pathogens, and modulate a normal immunological response. Therefore, modification of the intestinal microbiota in order to achieve, restore, and maintain favourable balance in the ecosystem, and the activity of microorganisms present in the gastrointestinal tract is necessary for the improved health condition of the host. The introduction of probiotics, prebiotics, or synbiotics into human diet is favourable for the intestinal microbiota. They may be consumed in the form of raw vegetables and fruit, fermented pickles, or dairy products. Another source may be pharmaceutical formulas and functional food. This paper provides a review of available information and summarises the current knowledge on the effects of probiotics, prebiotics, and synbiotics on human health. The mechanism of beneficial action of those substances is discussed, and verified study results proving their efficacy in human nutrition are presented.

Novel vitamin B12-producing Enterococcus spp. and preliminary in vitro evaluation of probiotic potentials

Vitamin B₁₂ is an essential nutrient required for crucial metabolic processes in humans. Vitamin B₁₂-producing lactic acid bacteria (LAB) have been attracting increased attentions currently because of the generally recognized as safe (GRAS) status. Most of recent studies focused on Lactobacillus, and little is known about B₁₂-producing Enterococcus. In the present study, five Enterococcus strains isolated from infant feces were identified as vitamin B₁₂ producers. Among them, Enterococcus faecium LZ86 had the highest B₁₂ production (499.8 ± 83.7 μg/L), and the B₁₂ compound from LZ86 was identified as the biological active adenosylcobalamin, using reversed phase high-performance liquid (RP-HPLC) chromatogram. We examined basic probiotic and safety properties of E. faecium LZ86 and found that it was able to survive harsh environmental conditions (hot temperature, cold temperature, ethanol and osmotic stresses), tolerate gastric acid (pH 2.0, 3 h) and bile salts (0.3%), and adhere to Caco-2 cells. We also showed that E. faecium LZ86 is devoid of transferable antibiotic resistance and potential virulence factors. Together, here we report a B₁₂-producing E. faecium strain LZ86 firstly, which has desirable probiotic properties and may serve as a good candidate for vitamin B₁₂ fortification in food industry.

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods

Consumer interest in healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand of biofunctional dairy foods. A number of commercial sources sell synthetic formulations of bioactive substances for use as dietary supplements. However, the bioactive-enrichment of health-oriented foods by naturally occurring microorganisms during dairy fermentation is in increased demand. While participating in milk fermentation, lactic acid bacteria can be exploited in situ as microbial sources for naturally enriching dairy products with a broad range of bioactive components that may cover different health aspects. Several of these bioactive metabolites are industrially and economically important, as they are claimed to exert diverse health-promoting activities on the consumer, such as anti-hypertensive, anti-inflammatory, and anti-diabetic, anti-oxidative, immune-modulatory, anti-cholesterolemic, or microbiome modulation. This review aims at discussing the potential of these health-supporting bacteria as starter or adjunct cultures for the elaboration of dairy foods with a broad spectrum of new functional properties and added value.

Food-Like Growth Conditions Support Production of Active Vitamin B12 by Propionibacterium freudenreichii 2067 without DMBI, the Lower Ligand Base, or Cobalt Supplementation

Propionibacterium freudenreichii is a traditional dairy bacterium and a producer of short chain fatty acids (propionic and acetic acids) as well as vitamin B12. In food applications, it is a promising organism for in situ fortification with B12 vitamin since it is generally recognized as safe (GRAS) and it is able to synthesize biologically active form of the vitamin. In the present study, vitamin B12 and pseudovitamin biosynthesis by P. freudenreichii was monitored by UHPLC as a function of growth in food-like conditions using a medium mimicking cheese environment, without cobalt or 5,6-dimethylbenzimidazole (DMBI) supplementation. Parallel growth experiments were performed in industrial-type medium known to support the biosynthesis of vitamin B12. The production of other key metabolites in the two media were determined by HPLC, while the global protein production was compared by gel-based proteomics to assess the effect of growth conditions on the physiological status of the strain and on the synthesis of different forms of vitamin. The results revealed distinct protein and metabolite production, which reflected the growth conditions and the potential of P. freudenreichii for synthesizing nutritionally relevant amounts of active vitamin B12 regardless of the metabolic state of the cells.

Anaerobes as Sources of Bioactive Compounds and Health Promoting Tools

Aerobic microorganisms have been sources of medicinal agents for several decades and an impressive variety of drugs have been isolated from their cultures, studied and formulated to treat or prevent diseases. On the other hand, anaerobes, which are believed to be the oldest life forms on earth and evolved remarkably diverse physiological functions, have largely been neglected as sources of bioactive compounds. However, results obtained from the limited research done so far show that anaerobes are capable of producing a range of interesting bioactive compounds that can promote human health. In fact, some of these bioactive compounds are found to be novel in their structure and/or mode of action.Anaerobes play health-promoting roles through their bioactive products as well as application of whole cells. The bioactive compounds produced by these microorganisms include antimicrobial agents and substances such as immunomodulators and vitamins. Bacteriocins produced by anaerobes have been in use as preservatives for about 40 years. Because these substances are effective at low concentrations, encounter relatively less resistance from bacteria and are safe to use, there is a growing interest in these antimicrobial agents. Moreover, several antibiotics have been reported from the cultures of anaerobes. Closthioamide and andrimid produced by Clostridium cellulolyticum and Pantoea agglomerans, respectively, are examples of novel antibiotics of anaerobe origin. The discovery of such novel bioactive compounds is expected to encourage further studies which can potentially lead to tapping of the antibiotic production potential of this fascinating group of microorganisms.Anaerobes are widely used in preparation of fermented foods and beverages. During the fermentation processes, these organisms produce a number of bioactive compounds including anticancer, antihypertensive and antioxidant substances. The well-known health promoting effect of fermented food is mostly due to these bioactive compounds. In addition to their products, whole cell anaerobes have very interesting applications for enhancing the quality of life. Probiotic anaerobes have been on the market for many years and are receiving growing acceptance as health promoters. Gut anaerobes have been used to treat patients suffering from severe Clostridium difficile infection syndromes including diarrhoea and colitis which cannot be treated by other means. Whole cell anaerobes are also studied to detect and cure cancer. In recent years, evidence is emerging that anaerobes constituting the microbiome are linked to our overall health. A dysfunctional microbiome is believed to be the cause of many diseases including cancer, allergy, infection, obesity, diabetes and several other disorders. Maintaining normal microflora is believed to alleviate some of these serious health problems. Indeed, the use of probiotics and prebiotics which favourably change the number and composition of the gut microflora is known to render a health promoting effect. Our interaction with the microbiome anaerobes is complex. In fact, not only our lives but also our identities are more closely linked to the anaerobic microbial world than we may possibly imagine. We are just at the beginning of unravelling the secret of association between the microbiome and human body, and a clear understanding of the association may bring a paradigm shift in the way we diagnose and treat diseases and disorders. This chapter highlights some of the work done on bioactive compounds and whole cell applications of the anaerobes that foster human health and improve the quality of life.

Vitamin B12 among Vegetarians: Status, Assessment and Supplementation

Cobalamin is an essential molecule for humans. It acts as a cofactor in one-carbon transfers through methylation and molecular rearrangement. These functions take place in fatty acid, amino acid and nucleic acid metabolic pathways. The deficiency of vitamin B12 is clinically manifested in the blood and nervous system where the cobalamin plays a key role in cell replication and in fatty acid metabolism. Hypovitaminosis arises from inadequate absorption, from genetic defects that alter transport through the body, or from inadequate intake as a result of diet. With the growing adoption of vegetarian eating styles in Western countries, there is growing focus on whether diets that exclude animal foods are adequate. Since food availability in these countries is not a problem, and therefore plant foods are sufficiently adequate, the most delicate issue remains the contribution of cobalamin, which is poorly represented in plants. In this review, we will discuss the status of vitamin B12 among vegetarians, the diagnostic markers for the detection of cobalamin deficiency and appropriate sources for sufficient intake, through the description of the features and functions of vitamin B12 and its absorption mechanism.

The Online Morphology Control and Dynamic Studies on Improving Vitamin B12 Production by Pseudomonas denitrificans with Online Capacitance and Specific Oxygen Consumption Rate

The relationship between the morphological character of Pseudomonas denitrificans and vitamin B12 synthesis based on real-time capacitance measurement and online specific oxygen consumption rate (Q O2) control was established for enhancing vitamin B12 production. Results demonstrated that the threshold Q O2 value lower than 2.0 mmol/gDCW/l would greatly stimulate the state transfer from the cell number growth phase to the cell elongation phase and promote rapid vitamin B12 biosynthesis, while the vitamin B12 biosynthesis rate could also be inhibited when the rate of cell's length-to-width ratio (ratio-LW) was higher than 10:1. Furthermore, the optimal morphology controlling strategy was achieved based on online Q O2 control, which increases the appropriate active cell numbers at the former phase, and then control the elongation of ratio-LW no more than 10:1 at the vitamin B12 biosynthesis phase. The maximal vitamin B12 production reached 239.7 mg/l at 168 h, which was improved by 14.7 % compared with the control (208 mg/l). This online controlling strategy would be effectively applied for improving industrial vitamin B12 fermentation.

BluB/CobT2 fusion enzyme activity reveals mechanisms responsible for production of active form of vitamin B₁₂ by Propionibacterium freudenreichii

Background

Propionibacterium freudenreichii is a food grade bacterium that has gained attention as a producer of appreciable amounts of cobalamin, a cobamide with activity of vitamin B₁₂. Production of active form of vitamin is a prerequisite for attempts to naturally fortify foods with B₁₂ by microbial fermentation. Active vitamin B₁₂ is distinguished from the pseudovitamin by the presence of 5,6-dimethylbenzimidazole (DMBI) as the lower ligand. Genomic data indicate that P. freudenreichii possesses a fusion gene, bluB/cobT2, coding for a predicted phosphoribosyltransferase/nitroreductase, which is presumably involved in production of vitamin B₁₂. Understanding the mechanisms affecting the synthesis of different vitamin forms is useful for rational strain selection and essential for engineering of strains with improved B₁₂ production properties.

Results

Here, we investigated the activity of heterologously expressed and purified fusion enzyme BluB/CobT2. Our results show that BluB/CoBT2 is responsible for the biosynthesis of the DMBI base and its activation into α-ribazole phosphate, preparing it for attachment as the lower ligand of cobalamin. The fusion enzyme was found to be efficient in metabolite channeling and the enzymes’ inability to react with adenine, a lower ligand present in the pseudovitamin, revealed a mechanism favoring the production of the active form of the vitamin. P. freudenreichii did not produce cobalamin under strictly anaerobic conditions, confirming the requirement of oxygen for DMBI synthesis. In vivo experiments also revealed a clear preference for incorporating DMBI over adenine into cobamide under both microaerobic and anaerobic conditions.

Conclusions

The herein described BluB/CobT2 is responsible for the production and activation of DMBI. Fusing those two activities results in high pressure towards production of the true vitamin B₁₂ by efficiently activating DMBI formed within the same enzymatic complex. This indicates that BluB/CobT2 is the crucial enzyme in the B₁₂ biosynthetic pathway of P. freudenreichii. The GRAS organism status and the preference for synthesizing active vitamin form make P. freudenreichii a unique candidate for the in situ production of vitamin B₁₂ within food products.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-015-0363-9) contains supplementary material, which is available to authorized users.