Selective carbohydrate utilization by lactobacilli and bifidobacteria

Cassava (Manihot esculenta) Brazilian cultivars have different chemical compositions, present prebiotic potential, and beneficial effects on the colonic microbiota of celiac individuals

The purpose of this study was to investigate the potential prebiotic properties of cassava cultivars from Northeast [Doce mel and Ourinho (OUR)] and South [Baiana, and IPR-Upira (UPI)] of Brazil in in vitro fermentation systems. The cultivars were evaluated for their chemical composition, and, then, two cultivars were selected (OUR and UPI) and subjected to in vitro gastrointestinal digestion to assess the effects on probiotics Lacticaseibacillus casei, Lactobacillus acidophilus, and Bifidobacterium animalis growth, metabolic activity, and prebiotic activity scores. Finally, the impact of cassava cultivars on the fecal microbiota of celiac individuals was evaluated using the 16S rRNA gene. Cassava cultivars have variable amounts of fiber, resistant starch, fructooligosaccharides (FOS), organic acids, phenolic compounds, and sugars, with OUR and UPI cultivars standing out. OUR and UPI cultivars contributed to the increase in the proliferation rates of L. casei (0.04-0.19), L. acidophilus (0.34-0.27), and B. animalis (0.10-0.03), resulting in more significant effects than FOS, an established prebiotic compound. Also, the positive scores of prebiotic activities with probiotic strains indicate OUR and UPI's ability to stimulate beneficial bacteria while limiting enteric competitors selectively. In addition, OUR and UPI promoted increased relative abundance of Bifidobacteriaceae, Enterococcaceae, and Lactobacillaceae in the fecal microbiota of celiac individuals while decreased Lachnospirales, Bacteroidales, and Oscillospirales. The results show that cassava cultivars caused beneficial changes in the composition and metabolic activity of the human intestinal microbiota of celiacs. OUR and UPI cultivars from the Northeast and South of Brazil could be considered potential prebiotic ingredients for use in the formulation of functional foods and dietary supplements.

Selective human milk oligosaccharide utilization by members of the Bifidobacterium pseudocatenulatum taxon

Human milk oligosaccharides (HMOs) are essentially unaffected by the digestive enzymes of the nursling and are known for their ability to enrich certain microbial species in the infant gut microbiota, in particular bifidobacteria. HMO metabolism has been studied in various bifidobacterial species such as B. breve, B. bifidum, and B. longum subsp. infantis. In the current study, we describe differential growth abilities elicited by twenty-three newly isolated Bifidobacterium pseudocatenulatum strains on particular HMOs, such as 2'-fucosyllactose (2'FL), 3-fucosyllactose (3FL), lacto-N-tetraose (LNT), and lacto-N-neotetraose (LNnT). Through gene-trait matching and comparative genome analysis, we identified genes involved in the degradation of fucosylated HMOs in this strain set, while we employed a transcriptomic approach to facilitate the identification and characterization of genes and associated enzymes involved in LNT metabolism by strain B. pseudocatenulatum MM0196. A total of 252 publicly available genomes of the B. pseudocatenulatum taxon were screened for homologs of the glycosyl hydrolases (GHs) identified here as being required for selected HMO metabolism. From this analysis, it is clear that all members of this species possess homologs of the genes involved in LNT degradation, while genes required for degradation of fucosylated HMOs are variably present.IMPORTANCEOur findings allow a better understanding of the complex interaction between Bifidobacterium and its host and provide a roadmap toward future applications of B. pseudocatenulatum as a probiotic with a focus on infant health. Furthermore, our investigations have generated information on the role of HMOs in shaping the infant gut microbiota, thus also facilitating applications of HMOs in infant nutrition, with potential extension into the mature or adult gut microbiota. Supplementation of HMOs is known to result in the modulation of bacterial communities toward a higher relative abundance of bifidobacteria, which in turn enforces their ability to modulate particular immune functions and strengthen the intestinal barrier. This work may therefore inspire future studies to improve the formulation of neonatal nutritional products, aimed at facilitating the development of a healthy digestive and immune system and reducing the differences in gut microbiota composition observed between breastfed and formula-fed babies or full-term and preterm infants.

Classifying compounds as prebiotics - scientific perspectives and recommendations

Microbiomes provide key contributions to health and potentially important therapeutic targets. Conceived nearly 30 years ago, the prebiotic concept posits that targeted modulation of host microbial communities through the provision of selectively utilized growth substrates provides an effective approach to improving health. Although the basic tenets of this concept remain the same, it is timely to address certain challenges pertaining to prebiotics, including establishing that prebiotic-induced microbiota modulation causes the health outcome, determining which members within a complex microbial community directly utilize specific substrates in vivo and when those microbial effects sufficiently satisfy selectivity requirements, and clarification of the scientific principles on which the term 'prebiotic' is predicated to inspire proper use. In this Expert Recommendation, we provide a framework for the classification of compounds as prebiotics. We discuss ecological principles by which substrates modulate microbiomes and methodologies useful for characterizing such changes. We then propose statistical approaches that can be used to establish causal links between selective effects on the microbiome and health effects on the host, which can help address existing challenges. We use this information to provide the minimum criteria needed to classify compounds as prebiotics. Furthermore, communications to consumers and regulatory approaches to prebiotics worldwide are discussed.

Comparative Study of Prebiotics for Infants Using a Fecal Culture System: Insights into Responders and Non-Responders

BACKGROUND

The gut microbiota of breast-fed infants is dominated by infant-type human-residential bifidobacteria (HRB) that contribute to infant health; thus, it is crucial to develop infant formulas that promote the establishment of a gut microbiota enriched with infant-type HRB, closely resembling that of breastfed infants.

METHODS

We compared various non-digestible prebiotic oligosaccharides and their combinations using a fecal culture system to explore which candidates could promote the growth of all infant-type HRB and rarely yield non-responders. The analysis included lactulose (LAC), raffinose (RAF), galactooligosaccharides (GOS), and short- and long-chain fructooligosaccharides. Fecal samples were collected from seven infants aged 1.5-10.2 months and cultured with each oligosaccharide individually or their combinations.

RESULTS

No single oligosaccharide effectively promoted the growth of all infant-type HRB, although GOS promoted the growth of HRB other than Bifidobacterium longum subsp. longum. Only the LAC/RAF/GOS group evenly and effectively promoted the growth of all infant-type HRB. Accordingly, acetate production was higher in fecal cultures supplemented with GOS or LAC/RAF/GOS than in the other cultures, suggesting that it is a superior combination for all infant-type HRB and rarely yields non-responders.

CONCLUSIONS

This study can aid in developing infant formulas that help align the gut microbiota of formula-fed infants with that of breastfed infants.

Disclosing α-lactalbumin impact on the intestinal and vaginal microbiota of women suffering from polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most widespread endocrinopathy affecting women of reproductive age with detrimental effects on life quality and health. Among several mechanisms involved in its aetiopathogenesis, recent studies have also postulated the involvement of the vaginal and intestinal microbiota in the development of this disorder. In this study, an accurate insight into the microbial changes associated with PCOS was performed through a pooled-analysis highlighting that this syndrome is characterized by intestinal and vaginal dysbiosis with a reduction of beneficial microorganisms and a higher proportion of potential pathogens. Based on this observation, we evaluated the ability of a milk-derived protein exerting positive outcomes in the management of PCOS, that is, α-lactalbumin (α-LA), to recover PCOS-related dysbiosis. In vitro experiments revealed that this protein improved the growth performances of members of two health-promoting bacterial genera, that is, Bifidobacterium and Lactobacillus, depleted in both intestinal and vaginal microbiota of PCOS-affected women. In addition, α-LA modulated the taxonomic composition and growth performances of the microbial players of the complex intestinal and vaginal microbiota. Finally, an in vivo pilot study further corroborated these observations. The oral administration of α-LA for 30 days to women with PCOS revealed that this protein may have a role in favouring the growth of health-promoting bacteria yet limiting the proliferation of potential pathogens. Overall, our results could pave the way to the use of α-LA as a valid compound with 'prebiotic effects' to limit/restore the PCOS-related intestinal and vaginal dysbiosis.

A double-blind intervention trial in healthy women demonstrates the beneficial impact on Bifidobacterium with low dosages of prebiotic galacto-oligosaccharides

Introduction

Galacto-oligosaccharides (GOS) are well-substantiated prebiotic substrates. Multiple studies have demonstrated a positive impact of GOS on gut microbiota composition and activity, so-far mainly related to Bifidobacterium. However, data on the beneficial impact at lower dosages in a healthy female population are limited. The primary aim of the current study was to reveal the effect of low dosages (1.3 and 2.0 g) of GOS on fecal Bifidobacterium abundance in healthy women. Other outcomes included the effect of low dosage of GOS on overall fecal microbiota composition and on self-perceived GI comfort, sleep quality and mental wellbeing.

Method

Eighty-eight healthy women (42-70 years, BMI 18.7-30 kg/m2) were included in this randomized, parallel, double-blind study of 6 weeks. The participants were stratified for fiber intake, BMI and age and randomized to consume either 1.3 or 2.0 g of GOS per day for 3 weeks after a control period of 3 weeks without any intervention. Fecal samples were collected for shotgun metagenomics sequencing at the start (t = -3) and end (t = 0) of the control period and at the end of the intervention period (t = 3). Self-perceived gut comfort, sleep quality, and mental wellbeing were assessed weekly. Hierarchical clustering of principal components was applied to data collected from study participants.

Results

The relative abundance of Bifidobacterium in feces increased significantly after 3 weeks of daily consumption of both 1.3 g (p < 0.01) and 2.0 g GOS (p < 0.01). This was accompanied by a significant shift in the overall microbiota composition for the dosage of 2.0 g GOS (p < 0.01). Participants that showed a larger increase in Bifidobacterium in the intervention period compared to the change in Bifidobacterium in the control period, defined as responders, showed a significant overall difference in initial fecal microbiota composition as compared to non-responders (p = 0.04) and a trend towards lower baseline levels of Bifidobacterium in responders (p = 0.10).

Conclusion

Daily consumption of a low dose of GOS can lead to an increase in the relative abundance of Bifidobacterium in feces of healthy women. Additionally, with 2.0 g GOS, the enrichment of Bifidobacterium is accompanied with a shift in the overall microbiota composition.Clinical trial registration: clinicaltrials.gov, identifier NCT05762965.

Unveiling metabolic pathways of selected plant-derived glycans by Bifidobacterium pseudocatenulatum

Bifidobacteria are commonly encountered members of the human gut microbiota that possess the enzymatic machinery necessary for the metabolism of certain plant-derived, complex carbohydrates. In the current study we describe differential growth profiles elicited by a panel of 21 newly isolated Bifidobacterium pseudocatenulatum strains on various plant-derived glycans. Using a combination of gene-trait matching and comparative genome analysis, we identified two distinct xylanases responsible for the degradation of xylan. Furthermore, three distinct extracellular α-amylases were shown to be involved in starch degradation by certain strains of B. pseudocatenulatum. Biochemical characterization showed that all three α-amylases can cleave the related substrates amylose, amylopectin, maltodextrin, glycogen and starch. The genes encoding these enzymes are variably found in the species B. pseudocatenulatum, therefore constituting a strain-specific adaptation to the gut environment as these glycans constitute common plant-derived carbohydrates present in the human diet. Overall, our study provides insights into the metabolism of these common dietary carbohydrates by a human-derived bifidobacterial species.

Investigating the potential of yacon (Smallanthus sonchifolius) juice in the development of organic apple-based snacks

This study investigates the potential of yacon (Smallanthus sonchifolius) juice for the development of prebiotic-rich organic apple-based snacks. Yacon syrup, primarily composed of fructan, inulin, fructooligosaccharides (FOS), and free sugars, represents a promising nutraceutical product. Its great potential in food processing, particularly as an innovative source of prebiotics, has been demonstrated both in vitro and in vivo since it is fermented specifically by lactobacilli and bifidobacteria. Our objective was to explore the feasibility of employing vacuum impregnation process to incorporate yacon juice into organic apples, followed by hot air drying for the formulation of dried organic apple-based snacks with health-enhancing attributes. We assessed the prebiotic and physicochemical characteristics of the impregnated snacks, also considering 50 days of storage at room temperature. Vacuum impregnation and air drying produced dried apple slices impregnated with yacon juice with good quality and stability. Higher levels of fructan (16-fold difference compared to non-impregnated apples) in the apple slices increased their prebiotic potential, promoting the growth and viability of cells within simulated intestinal fluid, including strains of Bifidobacterium animalis subsp. lactis BB -12, Bifidobacterium breve DSM 20091, Bifidobacterium longum subsp. infantis DSM 20088, Lacticaseibacillus rhamnosus GG and Lacticaseibacillus rhamnosus C112, even after prolonged storage. Remarkably, the physicochemical parameters of the impregnated and dried apple slices remained nearly constant and akin to the control samples. Therefore, the combination of vacuum impregnation and air drying has the potential to be used to produce enriched prebiotic organic apple snacks, providing consumers with additional health benefits, including enhanced gut health, with its associated implications, and increased satiety. This innovation could contribute to the development of health-promoting food products with improved nutritional profiles.

Utilization of diverse oligosaccharides for growth by Bifidobacterium and Lactobacillus species and their in vitro co-cultivation characteristics

Various approaches have been used to study the relationship between prebiotics and probiotics. The utilization of different carbohydrates by probiotics depends on the biochemical properties of the enzymes and substrates required by the microbial strain. However, few studies have systematically analyzed the ability of probiotics to utilize different prebiotics. Here, we investigated the effects of prebiotics from different manufacturers on the proliferation of 13 strains of the Lactobacillus group and the genus Bifidobacterium co-cultured in vitro. Inulin, fructose-oligosaccharide (FOS), and galactose-oligosaccharide (GOS) had broad growth-promoting effects. FOS significantly promoted the proliferation of B. longum. When strains from Lactobacillus group and Bifidobacterium were co-cultured, FOS caused each strain to proliferate cooperatively. GOS was effectively used by L. rhamnosus and L. reuteri for energy and growth promotion. L. casei and L. paracasei fully metabolized inulin; these strains performed better than other strains from Lactobacillus group and Bifidobacterium. Media containing a mixture of oligosaccharides had stronger effects on the growth of B. animalis subsp. lactis, L. acidophilus, and L. rhamnosus than media containing single oligosaccharides. Thus, different oligosaccharides had different effects on the growth of probiotics, providing a scientific basis for the use of synbiotics in health and related fields.

Gastrointestinal Dysmotility Predisposes to Colitis through Regulation of Gut Microbial Composition and Linoleic Acid Metabolism

Disrupted gastrointestinal (GI) motility is highly prevalent in patients with inflammatory bowel disease (IBD), but its potential causative role remains unknown. Herein, the role and the mechanism of impaired GI motility in colitis pathogenesis are investigated. Increased colonic mucosal inflammation is found in patients with chronic constipation (CC). Mice with GI dysmotility induced by genetic mutation or chemical insult exhibit increased susceptibility to colitis, dependent on the gut microbiota. GI dysmotility markedly decreases the abundance of Lactobacillus animlalis and increases the abundance of Akkermansia muciniphila. The reduction in L. animlalis, leads to the accumulation of linoleic acid due to compromised conversion to conjugated linoleic acid. The accumulation of linoleic acid inhibits Treg cell differentiation and increases colitis susceptibility via inducing macrophage infiltration and proinflammatory cytokine expression in macrophage. Lactobacillus and A. muciniphila abnormalities are also observed in CC and IBD patients, and mice receiving fecal microbiota from CC patients displayed an increased susceptibility to colitis. These findings suggest that GI dysmotility predisposes host to colitis development by modulating the composition of microbiota and facilitating linoleic acid accumulation. Targeted modulation of microbiota and linoleic acid metabolism may be promising to protect patients with motility disorder from intestinal inflammation.

Positive modulation of a new reconstructed human gut microbiota by Maitake extract helpfully boosts the intestinal environment in vitro

The human gut is a complex environment where the microbiota and its metabolites play a crucial role in the maintenance of a healthy state. The aim of the present work is the reconstruction of a new in vitro minimal human gut microbiota resembling the microbe-microbe networking comprising the principal phyla (Bacillota, Bacteroidota, Pseudomonadota, and Actinomycetota), to comprehend the intestinal ecosystem complexity. In the reductionist model, we mimicked the administration of Maitake extract as prebiotic and a probiotic formulation (three strains belonging to Lactobacillus and Bifidobacterium genera), evaluating the modulation of strain levels, the release of beneficial metabolites, and their health-promoting effects on human cell lines of the intestinal environment. The administration of Maitake and the selected probiotic strains generated a positive modulation of the in vitro bacterial community by qPCR analyses, evidencing the prominence of beneficial strains (Lactiplantibacillus plantarum and Bifidobacterium animalis subsp. lactis) after 48 hours. The bacterial community growths were associated with the production of metabolites over time through GC-MSD analyses such as lactate, butyrate, and propionate. Their effects on the host were evaluated on cell lines of the intestinal epithelium and the immune system, evidencing positive antioxidant (upregulation of SOD1 and NQO1 genes in HT-29 cell line) and anti-inflammatory effects (production of IL-10 from all the PBMCs). Therefore, the results highlighted a positive modulation induced by the synergic activities of probiotics and Maitake, inducing a tolerogenic microenvironment.

Effect of gut microbiome modulation on muscle function and cognition: the PROMOTe randomised controlled trial

Studies suggest that inducing gut microbiota changes may alter both muscle physiology and cognitive behaviour. Gut microbiota may play a role in both anabolic resistance of older muscle, and cognition. In this placebo controlled double blinded randomised controlled trial of 36 twin pairs (72 individuals), aged ≥60, each twin pair are block randomised to receive either placebo or prebiotic daily for 12 weeks. Resistance exercise and branched chain amino acid (BCAA) supplementation is prescribed to all participants. Outcomes are physical function and cognition. The trial is carried out remotely using video visits, online questionnaires and cognitive testing, and posting of equipment and biological samples. The prebiotic supplement is well tolerated and results in a changed gut microbiome [e.g., increased relative Bifidobacterium abundance]. There is no significant difference between prebiotic and placebo for the primary outcome of chair rise time (β = 0.579; 95% CI -1.080-2.239 p = 0.494). The prebiotic improves cognition (factor score versus placebo (β = -0.482; 95% CI,-0.813, -0.141; p = 0.014)). Our results demonstrate that cheap and readily available gut microbiome interventions may improve cognition in our ageing population. We illustrate the feasibility of remotely delivered trials for older people, which could reduce under-representation of older people in clinical trials. ClinicalTrials.gov registration: NCT04309292.

Microbiome assembly and stability during start-up of a full-scale, two-phase anaerobic digester fed cow manure and mixed organic feedstocks

Carbon transformations during anaerobic digestion are mediated by complex microbiomes, but their assembly is poorly understood, especially in full-scale digesters. Gene-centric metagenomics combining functional and taxonomic classification was performed for an on-farm digester during start-up. Cow manure and organic waste pre-treated in a hydrolysis tank were fed to the methane-producing digester and the volatile solids loading rate was slowly increased from 0 to 3.5 kg volatile solids m-3 d-1 over one year. The microbial community in the anaerobic digester exhibited a high ratio of archaea, which were dominated by hydrogenotrophic methanogens. Bacteria in the anaerobic digester had a high abundance of genes for ferredoxin cycling, H2 generation, and more metabolically complex fermentations than in the hydrolysis tank. In total, the results show that a functionally stable microbiome was achieved quickly during start-up and that the microbiome created in the low-pH hydrolysis tank did not persist in the downstream anaerobic digester.

Growth kinetics of Lactococcus lactis and Lactobacillus casei in liquid culture medium containing as prebiotics inulin or fructose

BACKGROUND

Predictive microbiology is a tool that allows us to evaluate the behavior of the concentration of biomass and estimated cells under extrinsic conditions, providing scientific and industrial benefits. In the present study, the growth of L. lactis and L. casei combined with inulin and fructose was modeled using the Gompertz sigmoidal growth functions and plotted using data obtained from batch culture in relation to biomass and cell concentration expressed as estimates in ln N (OD600nm and cells mL-1 ) as a function of time.

RESULTS

The results of the kinetic modeling indicated that (T1) A1B1 = L. lactis + fructose and (T4) A2B2 = L. casei + inulin presented the best function coefficients and best fits in most cases compared to the rest. The specific growth rate of the maximum acceleration was from 0.364 to 0.473 h-1 and 0.100 to 0.129 h-1 , the concentration of bacterial cells (A) was from 0.556 to 0.713 and 0.425 to 0.548 respectively and the time where (μ) occurred with a greater magnitude (L) fluctuated between 0.854 and 0.802 and when this time in (L) is very fast, it presents values of ≤0.072 to ≤0.092. Its coefficient of determination and/or multiple regression (R2 ) obtained in the two adjustments was 0.97.

CONCLUSION

It was possible to predict the influence of the carbon source on the behavior of maximum growth rates, higher consumption due to nutrient affinity and shorter growth time. © 2023 Society of Chemical Industry.

Selective utilization of gluco-oligosaccharides by lactobacilli: A mechanism study revealing the impact of glycosidic linkages and degree of polymerization on their utilization

Gluco-oligosaccharides (GlcOS) are potential prebiotics that positively modulate beneficial gut commensals like lactobacilli. For the rational design of GlcOS as prebiotics or combined with lactobacilli as synbiotics, it is important to establish the structure requirements of GlcOS and specificity toward lactobacilli. Herein, the utilization of 10 GlcOS with varied degrees of polymerization (DP) and glycosidic linkages by 7 lactobacilli strains (Levilactobacillus brevis ATCC 8287, Limosilactobacillus reuteri ATCC PTA 6475, Lacticaseibacillus rhamnosus ATCC 53103, Lentilactobacillus buchneri ATCC 4005, Limosilactobacillus fermentum FUA 3589, Lactiplantibacillus plantarum WCFS1, and Lactobacillus gasseri ATCC 33323) was studied. L. brevis ATCC 8287 was the only strain that grew on α/β-(1→4/6) linked disaccharides, whereas other strains showed diverse patterns, dependent on the availability of genes encoding sugar transporters and catabolic enzymes. The effect of DP on GlcOS utilization was strain dependent. β-(1→4) Linked cello-oligosaccharides (COS) supported the growth of L. brevis ATCC 8287 and L. plantarum WCFS1, and shorter COS (DP 2-3) were preferentially utilized over longer COS (DP 4-7) (consumption ≥90% vs. 40%-60%). α-(1→4) Linked maltotriose and maltodextrin (DP 2-11) were effectively utilized by L. brevis ATCC 8287, L. reuteri ATCC 6475, and L. plantarum WCFS1, but not L. fermentum FUA 3589. Growth of L. brevis ATCC 8287 on branched isomalto-oligosaccharides (DP 2-6) suggested preferential consumption of DP 2-3, but no preference between α-(1→6) and α-(1→4) linkages. The knowledge of the structure-specific GlcOS utilization by different lactobacilli from this study helps the structural rationale of GlcOS for prebiotic development.

Two extracellular α-arabinofuranosidases are required for cereal-derived arabinoxylan metabolism by Bifidobacterium longum subsp. longum

Members of the genus Bifidobacterium are commonly found in the human gut and are known to utilize complex carbohydrates that are indigestible by the human host. Members of the Bifidobacterium longum subsp. longum taxon can metabolize various plant-derived carbohydrates common to the human diet. To metabolize such polysaccharides, which include arabinoxylan, bifidobacteria need to encode appropriate carbohydrate-active enzymes in their genome. In the current study, we describe two GH43 family enzymes, denoted here as AxuA and AxuB, which are encoded by B. longum subsp. longum NCIMB 8809 and are shown to be required for cereal-derived arabinoxylan metabolism by this strain. Based on the observed hydrolytic activity of AxuA and AxuB, assessed by employing various synthetic and natural substrates, and based on in silico analyses, it is proposed that both AxuA and AxuB represent extracellular α-L-arabinofuranosidases with distinct substrate preferences. The variable presence of the axuA and axuB genes and other genes previously described to be involved in the metabolism of arabinose-containing glycans can in the majority cases explain the (in)ability of individual B. longum subsp. longum strains to grow on cereal-derived arabinoxylans and arabinan.

Molecular strategies for the utilisation of human milk oligosaccharides by infant gut-associated bacteria

A number of bacterial species are found in high abundance in the faeces of healthy breast-fed infants, an occurrence that is understood to be, at least in part, due to the ability of these bacteria to metabolize human milk oligosaccharides (HMOs). HMOs are the third most abundant component of human milk after lactose and lipids, and represent complex sugars which possess unique structural diversity and are resistant to infant gastrointestinal digestion. Thus, these sugars reach the infant distal intestine intact, thereby serving as a fermentable substrate for specific intestinal microbes, including Firmicutes, Proteobacteria, and especially infant-associated Bifidobacterium spp. which help to shape the infant gut microbiome. Bacteria utilising HMOs are equipped with genes associated with their degradation and a number of carbohydrate-active enzymes known as glycoside hydrolase enzymes have been identified in the infant gut, which supports this hypothesis. The resulting degraded HMOs can also be used as growth substrates for other infant gut bacteria present in a microbe-microbe interaction known as 'cross-feeding'. This review describes the current knowledge on HMO metabolism by particular infant gut-associated bacteria, many of which are currently used as commercial probiotics, including the distinct strategies employed by individual species for HMO utilisation.

Microbial modifications with Lycium barbarum L. oligosaccharides decrease hepatic fibrosis and mitochondrial abnormalities in mice

BACKGROUND

Lycium barbarum L. is a typical Chinese herbal and edible plant and are now consumed globally. Low molecular weight L. barbarum L. oligosaccharides (LBO) exhibit better antioxidant activity and gastrointestinal digestibility in vitro than high molecular weight polysaccharides. However, the LBO on the treatment of liver disease is not studied.

PURPOSE

Modification of the gut microbial ecosystem by LBO is a promising treatment for liver fibrosis.

STUDY DESIGN AND METHODS

Herein, LBO were prepared and characterized. CCl4-treated mice were orally gavaged with LBO and the effects on hepatic fibrosis and mitochondrial abnormalities were evaluated according to relevant indicators (gut microbiota, faecal metabolites, and physiological and biochemical indices).

RESULTS

The results revealed that LBO, a potential prebiotic source, is a pyranose cyclic oligosaccharide possessing α-glycosidic and β-glycosidic bonds. Moreover, LBO supplementation restored the configuration of the bacterial community, enhanced the proliferation of beneficial species in the gastrointestinal tract (e.g., Bacillus, Tyzzerella, Fournierella and Coriobacteriaceae UCG-002), improved microbial metabolic alterations (i.e., carbohydrate metabolism, vitamin metabolism and entero-hepatic circulation), and increased antioxidants, including doxepin, in mice. Finally, LBO administration reduced serum inflammatory cytokine and hepatic hydroxyproline levels, improved intestinal and hepatic mitochondrial functions, and ameliorated mouse liver fibrosis.

CONCLUSION

These findings indicate that LBO can be utilized as a prebiotic and has a remarkable ability to mitigate liver fibrosis.

Emerging trends and applications in health-boosting microorganisms-specific strains for enhancing animal health

Recent advancements in specific strain of probiotics have shown promising trends and applications in both ruminant and non-ruminant animal health. This study emphasizes the importance of tailored probiotics for these animal categories, discussing their potential benefits in improving nutrient utilization, growth performance, and disease management. The study also explores the different routes of probiotics administration, highlighting the various methods of delivery. Specifically, it highlights the benefits of probiotics in ruminant production performance, including enhanced rumen health, growth rates, milk production, and reduced digestive disorders. Additionally, it discusses the advantages of probiotics in non-ruminant farming, such as improved feed conversion efficiency, nutrient absorption, growth rates, immune responses, and reduced gastrointestinal issues, leading to increased productivity and profitability. In conclusion, recent advancements in specific strain of probiotics offer promising prospects for improving animal health. Tailored probiotics have shown potential in enhancing growth, nutrient utilization, and disease prevention, contributing to sustainable and effective animal husbandry practices.

Modulation of the Gut Microbiota by Tomato Flours Obtained after Conventional and Ohmic Heating Extraction and Its Prebiotic Properties

Several studies have supported the positive functional health effects of both prebiotics and probiotics on gut microbiota. Among these, the selective growth of beneficial bacteria due to the use of prebiotics and bioactive compounds as an energy and carbon source is critical to promote the development of healthy microbiota within the human gut. The present work aimed to assess the fermentability of tomato flour obtained after ohmic (SFOH) and conventional (SFCONV) extraction of phenolic compounds and carotenoids as well as their potential impact upon specific microbiota groups. To accomplish this, the attained bagasse flour was submitted to an in vitro simulation of gastrointestinal digestion before its potential fermentability and impact upon gut microbiota (using an in vitro fecal fermentation model). Different impacts on the probiotic strains studied were observed for SFCONV promoting the B. animalis growth, while SFOH promoted the B. longum, probably based on the different carbohydrate profiles of the flours. Overall, the flours used were capable of functioning as a direct substrate to support potential prebiotic growth for Bifidus longum. The fecal fermentation model results showed the highest Bacteroidetes growth with SFOH and the highest values of Bacteroides with SFCONV. A correlation between microorganisms' growth and short-chain fatty acids was also found. This by-product seems to promote beneficial effects on microbiota flora and could be a potential prebiotic ingredient, although more extensive in vivo trials would be necessary to confirm this.

Structural, in vitro digestion, and fermentation characteristics of lotus leaf flavonoids

Bioaccessibility and bioactivity of flavonoids in lotus leaves are related to their characteristics in gastrointestinal digestion and colonic fermentation. The aim of this study is to investigate the stability of lotus leaf flavonoids (LLF) in simulated gastrointestinal digestion, and its modulation on gut microbiota in vitro fermentation. Results showed that LLF mainly consisted of quercetin-3-O-galactoside, quercetin-3-O-glucuronide, quercetin-3-O-glucoside, and kaempferol-3-O-glucoside. These flavonoids kept stability with only a small fraction degraded in simulated gastric and intestinal fluids. In vitro fermentation, LLF stimulated the growth of Actinobacteria and Firmicutes, inhibited the growth of Proteobacteria, and induced the production of fermentation gases and short-chain fatty acids. Interestingly, supplementation of soluble starch significantly improved the utilization of LLF by the intestinal flora. These results revealed that LLF shaped a unique biological web with Lactobacillus and Bifidobacterium spp. as the core of the biological network, which would be more beneficial to gut health.

The Potential of an Inexpensive Plant-Based Medium for Halal and Vegetarian Starter Culture Preparation

The restrictions for halal and vegetarian fermented products apply not only to the food ingredients, but also to the inoculum media. The utilization of a medium for lactic acid bacteria (LAB) leads to some issues from animal-derived proteins sources that may be doubtful for halal and/or vegetarian use. This study aimed to develop a plant-based medium for culturing and maintaining LAB. The result demonstrated that 10 g/L soybean powder in sweet potato extract was suitable for cultivating Lactiplantibacillus plantarum TISTR 2075 with no significant difference (p < 0.05) from MRS (de Man, Rogosa and Sharpe) in the cell number (9.12 log CFU/mL) and specific growth rate (0.04). The feasibility of a plant-based medium to grow and maintain the LAB strains from different origins was evaluated. Compared to MRS, Lpb. plantarum TISTR 2075, Lpb. plantarum MW3, and Lacticaseibacillus casei TISTR 1463 could grow almost as well in a plant-based medium. This medium was also suitable for maintaining the viability of LAB during storage, especially when subjected to slant agar stock culture. It is practical and costs at least 10 times less than MRS. Thus, this study created a low-cost plant-based medium that could be used in laboratories, especially for applications in halal and vegetarian food products.

Prebiotic Consumption Alters Microbiota but Not Biological Markers of Stress and Inflammation or Mental Health Symptoms in Healthy Adults: A Randomized, Controlled, Crossover Trial

BACKGROUND

Chronic stress contributes to systemic inflammation and diminished mental health. Although animal work suggests strong links with the microbiota-gut-brain axis, clinical trials investigating the effectiveness of prebiotics in improving mental health and reducing inflammation are lacking.

OBJECTIVES

We aimed to determine fructooligosaccharide (FOS) and galactooligosaccharide (GOS) effects on biological markers of stress and inflammation and mental health symptoms in adults. Secondary outcomes included fecal microbiota and metabolites, digestive function, emotion, and sleep.

METHODS

Twenty-four healthy adults (25-45 y; 14 females, 10 males; BMI, 29.3 ± 1.8 kg/m²) from central Illinois participated in a 2-period, randomized, controlled, single-blinded crossover trial. Interventions included the prebiotic (PRE) treatment (237 mL/d Lactaid low-fat 1% milk, 5 g/d FOS, 5 g/d GOS) and control (CON) (237 mL/d Lactaid), which were consumed in counterbalanced order for 4 wk each, separated by ≥4-wk washout. Inflammatory markers were measured in blood plasma (>10-h fast) and cortisol in urine. The Depression Anxiety Stress Scales-42 assessed mental health symptoms. Fecal samples were collected for 16S rRNA gene (V4 region) sequencing and analysis. Emotion was measured by rating images from a computer task. Sleep was assessed using 7-d records and accelerometers. Change scores were analyzed using linear mixed models with treatment and baseline covariate as fixed effects and participant ID as the random effect.

RESULTS

There were no differences in change scores between PRE and CON treatments on biological markers of stress and inflammation or mental health. PRE increased change in percent sequences (q = 0.01) of Actinobacteriota (CON: 0.46 ± 0.70%; PRE: 5.40 ± 1.67%) and Bifidobacterium (CON: -1.72 ± 0.43%; PRE: 4.92 ± 1.53%). There were also no differences in change scores between treatments for microbial metabolites, digestive function, emotion, or sleep quality.

CONCLUSIONS

FOS+GOS did not affect biological markers of stress and inflammation or mental health symptoms in healthy adults; however, it increased Bifidobacterium.

CLINICAL TRIAL REGISTRY

NCT04551937, www.

CLINICALTRIALS

gov.

Infant Fecal Fermentations with Galacto-Oligosaccharides and 2′-Fucosyllactose Show Differential Bifidobacterium longum Stimulation at Subspecies Level

The objective of the current study was to evaluate the potential of 2′-FL and GOS, individually and combined, in beneficially modulating the microbial composition of infant and toddler (12–18 months) feces using the micro-Matrix bioreactor. In addition, the impacts of GOS and 2′-FL, individually and combined, on the outgrowth of fecal bifidobacteria at (sub)species level was investigated using the baby M-SHIME® model. For young toddlers, significant increases in the genera Bifidobacterium, Veillonella, and Streptococcus, and decreases in Enterobacteriaceae, Clostridium XIVa, and Roseburia were observed in all supplemented fermentations. In addition, GOS, and combinations of GOS and 2′-FL, increased Collinsella and decreased Salmonella, whereas 2′-FL, and combined GOS and 2′-FL, decreased Dorea. Alpha diversity increased significantly in infants with GOS and/or 2′-FL, as well as the relative abundances of the genera Veillonella and Akkermansia with 2′-FL, and Lactobacillus with GOS. Combinations of GOS and 2′-FL significantly stimulated Veillonella, Lactobacillus, Bifidobacterium, and Streptococcus. In all supplemented fermentations, Proteobacteria decreased, with the most profound decreases accomplished by the combination of GOS and 2′-FL. When zooming in on the different (sub)species of Bifidobacterium, GOS and 2’-FL were shown to be complementary in stimulating breast-fed infant-associated subspecies of Bifidobacterium longum in a dose-dependent manner: GOS stimulated Bifidobacterium longum subsp. longum, whereas 2′-FL supported outgrowth of Bifidobacterium longum subsp. infantis.

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

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

Synergistic Antioxidant Effect of Prebiotic Ginseng Berries Extract and Probiotic Strains on Healthy and Tumoral Colorectal Cell Lines

Oxidative stress caused by reactive oxygen species (ROS, O2•−, HO•, and H2O2) affects the aging process and the development of several diseases. A new frontier on its prevention includes functional foods with both specific probiotics and natural extracts as antioxidants. In this work, Panax ginseng C.A. Meyer berries extract was characterized for the presence of beneficial molecules (54.3% pectin-based polysaccharides and 12% ginsenosides), able to specifically support probiotics growth (OD600nm > 5) with a prebiotic index of 0.49. The administration of the extract to a probiotic consortium induced the production of short-chain fatty acids (lactic, butyric, and propionic acids) and other secondary metabolites derived from the biotransformation of Ginseng components. Healthy and tumoral colorectal cell lines (CCD841 and HT-29) were then challenged with these metabolites at concentrations of 0.1, 0.5, and 1 mg/mL. The cell viability of HT-29 decreased in a dose-dependent manner after the exposition to the metabolites, while CCD841 vitality was not affected. Regarding ROS production, the metabolites protected CCD841 cells, while ROS levels were increased in HT-29 cells, potentially correlating with the less functionality of glutathione S-transferase, catalase, and total superoxide dismutase enzymes, and a significant increase in oxidized glutathione.

Characterization of the Biological Activities of a New Polyphenol-Rich Extract from Cinnamon Bark on a Probiotic Consortium and Its Action after Enzymatic and Microbial Fermentation on Colorectal Cell Lines

Cinnamon polyphenols are known as health-promoting agents. However, their positive impact depends on the extraction method and their bioaccessibility after digestion. In this work, cinnamon bark polyphenols were extracted in hot water and subjected to an in vitro enzymatic digestion. After a preliminary characterization of total polyphenols and flavonoids (respectively 520.05 ± 17.43 µgGAeq/mg and 294.77 ± 19.83 µgCATeq/mg powder extract), the extract antimicrobial activity was evidenced only against Staphylococcus aureus and Bacillus subtilis displaying a minimum inhibition growth concentration value of 2 and 1.3 mg/mL, respectively, although it was lost after in vitro extract digestion. The prebiotic potential was evaluated on probiotic Lactobacillus and Bifidobacterium strains highlighting a high growth on the in vitro digested cinnamon bark extract (up to 4 × 10⁸ CFU/mL). Thus, the produced SCFAs and other secondary metabolites were extracted from the broth cultures and determined via GC-MSD analyses. The viability of healthy and tumor colorectal cell lines (CCD841 and SW480) was assayed after the exposition at two different concentrations (23 and 46 µgGAeq/mL) of the cinnamon extract, its digested, and the secondary metabolites produced in presence of cinnamon extract or its digested, showing positive protective effects against a tumorigenic condition.

Validity of food additive maltodextrin as placebo and effects on human gut physiology: systematic review of placebo-controlled clinical trials

PURPOSE

Maltodextrin (MDX) is a polysaccharide food additive commonly used as oral placebo/control to investigate treatments/interventions in humans. The aims of this study were to appraise the MDX effects on human physiology/gut microbiota, and to assess the validity of MDX as a placebo-control.

METHODS

We performed a systematic review of randomized-placebo-controlled clinical trials (RCTs) where MDX was used as an orally consumed placebo. Data were extracted from study results where effects (physiological/microbial) were attributed (or not) to MDX, and from study participant outcomes data, before-and-after MDX consumption, for post-publication 're-analysis' using paired-data statistics.

RESULTS

Of two hundred-sixteen studies on 'MDX/microbiome', seventy RCTs (n = 70) were selected for analysis. Supporting concerns regarding the validity of MDX as a placebo, the majority of RCTs (60%, CI 95% = 0.48-0.76; n = 42/70; Fisher-exact p = 0.001, expected < 5/70) reported MDX-induced physiological (38.1%, n = 16/42; p = 0.005), microbial metabolite (19%, n = 8/42; p = 0.013), or microbiome (50%, n = 21/42; p = 0.0001) effects. MDX-induced alterations on gut microbiome included changes in the Firmicutes and/or Bacteroidetes phyla, and Lactobacillus and/or Bifidobacterium species. Effects on various immunological, inflammatory markers, and gut function/permeability were also documented in 25.6% of the studies (n = 10/42). Notably, there was considerable variability in the direction of effects (decrease/increase), MDX dose, form (powder/pill), duration, and disease/populations studied. Overall, only 20% (n = 14/70; p = 0.026) of studies cross-referenced MDX as a justifiable/innocuous placebo, while 2.9% of studies (n = 2/70) acknowledged their data the opposite.

CONCLUSION

Orally-consumed MDX often (63.9% of RCTs) induces effects on human physiology/gut microbiota. Such effects question the validity of MDX as a placebo-control in human clinical trials.

Biotransformation of sucrose rich Maple syrups into fructooligosaccharides, oligolevans and levans using levansucrase biocatalyst: Bioprocess optimization and prebiotic activity assessment

Maple syrup was investigated as a source to produce FOSs and β-(2-6)-linked-oligolevans/levans. The modulation of this biotransformation was achieved through the control of Maple syrup °Bx and reaction conditions. Reaction time was identified as the most influential factor for the oligolevans/FOSs production in Maple syrup 30°Bx reaction system as well as for the oligolevans/levans synthesis in the 66°Bx one. In the predictive model of oligolevans/levans production in Maple syrup 60°Bx, the interactive effect between levansucrase unit and reaction time was significant (p-value of 0.0008). The optimal conditions for oligolevans/FOSs production (109.20 g/L) in Maple syrup 30°Bx were 3.73 U/mL, pH 6.60 and 23.12 h; while 5 U/mL, pH 6.04 and 29.92 h were identified as the optimal conditions for oligolevans/levans production (147.09 g/L) in Maple syrup 66°Bx. As compared to inulin-type commercial FOSs, the fermentation of oligolevans/FOSs from Maple syrup led to a higher count of Lactobacillus acidophilus and Bifidobacterium lactis and resulted in a higher production of lactic acid. This study lays the foundation for the biotransformation of Maple syrups into functional prebiotic ingredients.

Babies, Bugs, and Barriers: Dietary Modulation of Intestinal Barrier Function in Early Life

The intestinal barrier is essential in early life to prevent infection, inflammation, and food allergies. It consists of microbiota, a mucus layer, an epithelial layer, and the immune system. Microbial metabolites, the mucus, antimicrobial peptides, and secretory immunoglobulin A (sIgA) protect the intestinal mucosa against infection. The complex interplay between these functionalities of the intestinal barrier is crucial in early life by supporting homeostasis, development of the intestinal immune system, and long-term gut health. Exclusive breastfeeding is highly recommended during the first 6 months. When breastfeeding is not possible, milk-based infant formulas are the only safe alternative. Breast milk contains many bioactive components that help to establish the intestinal microbiota and influence the development of the intestinal epithelium and the immune system. Importantly, breastfeeding lowers the risk for intestinal and respiratory tract infections. Here we review all aspects of intestinal barrier function and the nutritional components that impact its functionality in early life, such as micronutrients, bioactive milk proteins, milk lipids, and human milk oligosaccharides. These components are present in breast milk and can be added to milk-based infant formulas to support gut health and immunity. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Microbiome-based interventions to modulate gut ecology and the immune system

The gut microbiome lies at the intersection between the environment and the host, with the ability to modify host responses to disease-relevant exposures and stimuli. This is evident in how enteric microbes interact with the immune system, e.g., supporting immune maturation in early life, affecting drug efficacy via modulation of immune responses, or influencing development of immune cell populations and their mediators. Many factors modulate gut ecosystem dynamics during daily life and we are just beginning to realise the therapeutic and prophylactic potential of microbiome-based interventions. These approaches vary in application, goal, and mechanisms of action. Some modify the entire community, such as nutritional approaches or faecal microbiota transplantation, while others, such as phage therapy, probiotics, and prebiotics, target specific taxa or strains. In this review, we assessed the experimental evidence for microbiome-based interventions, with a particular focus on their clinical relevance, ecological effects, and modulation of the immune system.

How water-soluble saccharides drive the metabolism of lactic acid bacteria during fermentation of brewers' spent grain

We proposed a novel phenomic approach to track the effect of short-term exposures of Lactiplantibacillus plantarum and Leuconostoc pseudomesenteroides to environmental pressure induced by brewers' spent grain (BSG)-derived saccharides. Water-soluble BSG-based medium (WS-BSG) was chosen as model system. The environmental pressure exerted by WS-BSG shifted the phenotypes of bacteria in species- and strains-dependent way. The metabolic drift was growth phase-dependent and likely underlay the diauxic profile of organic acids production by bacteria in response to the low availability of energy sources. Among pentosans, metabolism of arabinose was preferred by L. plantarum and xylose by Leuc. pseudomesenteroides as confirmed by the overexpression of related genes. Bayesian variance analysis showed that phenotype switching towards galactose metabolism suffered the greatest fluctuation in L. plantarum. All lactic acid bacteria strains utilized more intensively sucrose and its plant-derived isomers. Sucrose-6-phosphate activity in Leuc. pseudomesenteroides likely mediated the increased consumption of raffinose. The increased levels of some phenolic compounds suggested the involvement of 6-phospho-β-glucosidases in β-glucosides degradation. Expression of genes encoding β-glucoside/cellobiose-specific EII complexes and phenotyping highlighted an increased metabolism for cellobiose. Our reconstructed metabolic network will improve the understanding of how lactic acid bacteria may transform BSG into suitable food ingredients.

Determination of β-Galactooligosaccharides (GOS) in Infant Formula and Adult Nutritionals: Single-Laboratory Validation, First Action 2021.01

BACKGROUND

β-Galactooligosaccharides (GOS) are typically used in infant formula and adult nutritionals as a source of nondigestible oligosaccharides, which may bring beneficial effects through modulation of the gut microbiota. However, suitable methods for the determination of GOS in products with a high background of lactose do not exist.

OBJECTIVE

The aim of this work was to develop a method suitable for the determination of GOS in infant formula and adult nutritionals and demonstrate suitability through single laboratory validation.

METHODS

Reducing oligosaccharides are labeled with 2-aminobenzamide (2AB), separated by hydrophilic interaction LC, and determined assuming that all oligosaccharides give an equimolar response in the detector. The same sample is analyzed a second time after treatment with β-galactosidase to remove GOS. The difference in the determined oligosaccharides between the two measurements will be the GOS content of the sample. The method was validated in a single laboratory on infant formula and adult nutritionals.

RESULTS

Recoveries were in the range 91.5-102%, relative standards of deviation (RSDr) were in the range 0.7-5.99%, and one sample had an RSDr of 8.30%. Except for the one sample with an RSDr of 8.30%, the performance is within the requirements outlined in the Standard Method Performance Requirements, which specifies recoveries in the range 90-110% and RSDr of below 6%.

CONCLUSIONS

The method is suitable for the determination of GOS in infant formula and adult nutritionals.

HIGHLIGHTS

A method has been developed which is suitable for the determination of GOS in products with a high background concentration of lactose (infant fromula and adult nutritionals). The method does not require access to the GOS ingredient used for the production of the finished product. It is also possible to separately quantify the amount of GOS containing three or more monomeric units in order to support dietary fibre analysis.

Prebiotic Galacto-Oligosaccharides Impact Stool Frequency and Fecal Microbiota in Self-Reported Constipated Adults: A Randomized Clinical Trial

Constipation is a major issue for 10-20% of the global population. In a double-blind randomized placebo-controlled clinical trial, we aimed to determine a dose-response effect of galacto-oligosaccharides (GOS) on stool characteristics and fecal microbiota in 132 adults with self-reported constipation according to Rome IV criteria (including less than three bowel movements per week). Subjects (94% females, aged: 18-59 years) received either 11 g or 5.5 g of Biotis^TM GOS, or a control product, once daily for three weeks. Validated questionnaires were conducted weekly to study primarily stool frequency and secondary stool consistency. At base- and endline, stool samples were taken to study fecal microbiota. A trend towards an increased stool frequency was observed after the intervention with 11 g of GOS compared to control. While during screening everybody was considered constipated, not all subjects (n = 78) had less than three bowel movements per week at baseline. In total, 11 g of GOS increased stool frequency compared to control in subjects with a low stool frequency at baseline (≤3 bowel movements per week) and in self-reported constipated adults 35 years of age or older. A clear dose-response of GOS was seen on fecal Bifidobacterium, and 11 g of GOS significantly increased Anaerostipes hadrus. In conclusion, GOS seems to be a solution to benefit adults with a low stool frequency and middle-aged adults with self-reported constipation.

The antagonistic activity of the synbiotic containing Lactobacillus acidophilus and pineapple residue FOS against pathogenic bacteria

Fructooligosaccharide is used widely in many foods and pharmaceutical industries and produced by using different ways such as extracting it from plants or producing it by using plants and microorganisms' enzymes. In a previous study, we extracted Fructosyltransferase (Ftase) enzyme from pineapple residue and produced FOS. In this study, we measured the antagonistic activity of two synbiotics, the first synbiotic containing Lactobacillus acidophilus and the produced FOS, the second synbiotic containing Lactobacillus acidophilus and standard FOS, against pathogenic bacteria (P. aeruginosa, E. coli, S. aureus and B cereus). The results showed that the antagonistic activity of both synbiotic types was very close, as there were no significant differences between them except in the antagonistic activity against S. aureus, there was a significant difference between the synbiotic containing the standard FOS, which was the highest in its antagonistic activity compared to the synbiotic containing the produced FOS in this study. The activity of the fructooligosaccharide (FOS) extracted from pineapple residue was evident in enhancing the activity of the probiotic bacteria (L. acidophilus), which had a major role in the production of acids and compounds that inhibited the pathogenic bacteria. The diameters of inhibition areas in the current study ranged between 19.33-28 mm, and E. coli was more susceptible to inhibition, followed by S. aureus, P. aeruginosa, and B. cereus, respectively.

In vitro Effects of Prebiotics and Synbiotics on Apis cerana Gut Microbiota

This study aimed to investigate in vitro effects of the selected prebiotics alone, and in combination with two potential probiotic Lactobacillus strains on the microbial composition of Apis cerana gut microbiota and acid production. Four prebiotics, inulin, fructo-oligosaccharides, xylo-oligosaccharides, and isomalto-oligosaccharides were chosen, and glucose served as the carbon source. Supplementation of this four prebiotics increased numbers of Bifidobacterium and lactic acid bacteria while decreasing the pH value of in vitro fermentation broth inoculated with A. cerana gut microbiota compared to glucose. Then, two potential probiotics derived from A. cerana gut at different dosages, Lactobacillus helveticus KM7 and Limosilactobacillus reuteri LP4 were added with isomalto-oligosaccharides in fermentation broth inoculated with A. cerana gut microbiota, respectively. The most pronounced impact was observed with isomalto-oligosaccharides. Compared to isomalto-oligosaccharides alone, the combination of isomalto-oligosaccharides with both lactobacilli strains induced the growth of Bifidobacterium, LAB, and total bacteria and reduced the proliferation of Enterococcus and fungi. Consistent with these results, the altered metabolic activity was observed as lowered pH in in vitro culture of gut microbiota supplemented with isomalto-oligosaccharides and lactobacilli strains. The symbiotic impact varied with the types and concentration of Lactobacillus strains and fermentation time. The more effective ability was observed with IMO combined with L. helveticus KM7. These results suggested that isomalto-oligosaccharides could be a potential prebiotic and symbiotic with certain lactobacilli strains on A. cerana gut microbiota.

Term Infant Formulas Influencing Gut Microbiota: An Overview

Intestinal colonization of the neonate is highly dependent on the term of pregnancy, the mode of delivery, the type of feeding [breast feeding or formula feeding]. Postnatal immune maturation is dependent on the intestinal microbiome implementation and composition and type of feeding is a key issue in the human gut development, the diversity of microbiome, and the intestinal function. It is well established that exclusive breastfeeding for 6 months or more has several benefits with respect to formula feeding. The composition of the new generation of infant formulas aims in mimicking HM by reproducing its beneficial effects on intestinal microbiome and on the gut associated immune system (GAIS). Several approaches have been developed currently for designing new infant formulas by the addition of bioactive ingredients such as human milk oligosaccharides (HMOs), probiotics, prebiotics [fructo-oligosaccharides (FOSs) and galacto-oligosaccharides (GOSs)], or by obtaining the so-called post-biotics also known as milk fermentation products. The aim of this article is to guide the practitioner in the understanding of these different types of Microbiota Influencing Formulas by listing and summarizing the main concepts and characteristics of these different models of enriched IFs with bioactive ingredients.

Bifidobacterial β-Galactosidase-Mediated Production of Galacto-Oligosaccharides: Structural and Preliminary Functional Assessments

In the current study the ability of four previously characterized bifidobacterial β-galactosidases (designated here as BgaA, BgaC, BgaD, and BgaE) to produce galacto-oligosaccharides (GOS) was optimized. Of these enzymes, BgaA and BgaE were found to be promising candidates for GOS production (and the corresponding GOS mixtures were called GOS-A and GOS-E, respectively) with a GOS concentration of 19.0 and 40.3% (of the initial lactose), respectively. GOS-A and GOS-E were partially purified and structurally characterized. NMR analysis revealed that the predominant (non-lactose) disaccharide was allo-lactose in both purified GOS preparations. The predominant trisaccharide in GOS-A and GOS-E was shown to be 3′-galactosyllactose, with lower levels of 6′-galactosyllactose and 4′-galactosyllactose. These three oligosaccharides have also been reported to occur in human milk. Purified GOS-A and GOS-E were shown to be able to support bifidobacterial growth similar to a commercially available GOS. In addition, GOS-E and the commercially available GOS were shown to be capable of reducing Escherichia coli adhesion to a C2BBe1 cell line. Both in vitro bifidogenic activity and reduced E. coli adhesion support the prebiotic potential of GOS-E and GOS-A.

Building Robust Assemblages of Bacteria in the Human Gut in Early Life

The neonatal body provides a range of potential habitats, such as the gut, for microbes. These sites eventually harbor microbial communities (microbiotas). A "complete" (adult) gut microbiota is not acquired by the neonate immediately after birth. Rather, the exclusive, milk-based nutrition of the infant encourages the assemblage of a gut microbiota of low diversity, usually dominated by bifidobacterial species. The maternal fecal microbiota is an important source of bacterial species that colonize the gut of infants, at least in the short-term. However, development of the microbiota is influenced by the use of human milk (breast feeding), infant formula, preterm delivery of infants, caesarean delivery, antibiotic administration, family details and other environmental factors. Following the introduction of weaning (complementary) foods, the gut microbiota develops in complexity due to the availability of a diversity of plant glycans in fruits and vegetables. These glycans provide growth substrates for the bacterial families (such as members of the Ruminococcaceae and Lachnospiraceae) that, in due course, will dominate the gut microbiota of the adult. Although current data are often fragmentary and observational, it can be concluded that the nutrition that a child receives in early life is likely to impinge not only on the development of the microbiota at that time but also on the subsequent lifelong, functional relationships between the microbiota and the human host. The purpose of this review, therefore, is to discuss the importance of promoting the assemblage of functionally robust gut microbiotas at appropriate times in early life.

Prebiotic Effect of Maitake Extract on a Probiotic Consortium and Its Action after Microbial Fermentation on Colorectal Cell Lines

Maitake (Grifola frondosa) is a medicinal mushroom known for its peculiar biological activities due to the presence of functional components, including dietary fibers and glucans, that can improve human health through the modulation of the gut microbiota. In this paper, a Maitake ethanol/water extract was prepared and characterized through enzymatic and chemical assays. The prebiotic potential of the extract was evaluated by the growth of some probiotic strains and of a selected probiotic consortium. The results revealed the prebiotic properties due to the stimulation of the growth of the probiotic strains, also in consortium, leading to the production of SCFAs, including lactic, succinic, and valeric acid analyzed via GC-MSD. Then, their beneficials effect were employed in evaluating the vitality of three different healthy and tumoral colorectal cell lines (CCD841, CACO-2, and HT-29) and the viability rescue after co-exposure to different stressor agents and the probiotic consortium secondary metabolites. These metabolites exerted positive effects on colorectal cell lines, in particular in protection from reactive oxygen species.

Identification of Lactobacillus Strains Capable of Fermenting Fructo-Oligosaccharides and Inulin

Novel probiotic strains that can ferment prebiotics are important for functional foods. The utilization of prebiotics is strain specific, so we screened 86 Lactobacillus strains and compared them to Bifidobacterium breve 2141 for the ability to grow and produce SCFA when 1% inulin or fructo-oligosaccharides (FOS) were provided as the carbon source in batch fermentations. When grown anaerobically at 32 °C, ten Lactobacillus strains grew on both prebiotic substrates (OD₆₀₀ ≥ 1.2); while Lactobacillus coryniformis subsp. torquens B4390 grew only in the presence of inulin. When the growth temperature was increased to 37 °C to simulate the human body temperature, four of these strains were no longer able to grow on either prebiotic. Additionally, L. casei strains 4646 and B441, and L. helveticus strains B1842 and B1929 did not require anaerobic conditions for growth on both prebiotics. Short-chain fatty acid analysis was performed on cell-free supernatants. The concentration of lactic acid produced by the ten Lactobacillus strains in the presence of prebiotics ranged from 73-205 mM. L. helveticus B1929 produced the highest concentration of acetic acid ~19 mM, while L. paraplantarum B23115 and L. paracasei ssp. paracasei B4564 produced the highest concentrations of propionic (1.8-4.0 mM) and butyric (0.9 and 1.1 mM) acids from prebiotic fermentation. L. mali B4563, L. paraplantarum B23115 and L. paracasei ssp. paracasei B4564 were identified as butyrate producers for the first time. These strains hold potential as synbiotics with FOS or inulin in the development of functional foods, including infant formula.

Galacto-oligosaccharides as infant prebiotics: production, application, bioactive activities and future perspectives

Galacto-oligosaccharides (GOS) are non-digestible oligosaccharides characterized by a mix of structures that vary in their degree of polymerization (DP) and glycosidic linkage between the galactose moieties or between galactose and glucose. They have enjoyed extensive scientific scrutiny, and their health-promoting effects are supported by a large number of scientific and clinical studies. A variety of GOS-associated health-promoting effects have been reported, such as growth promotion of beneficial bacteria, in particular bifidobacteria and lactobacilli, inhibition of pathogen adhesion and improvement of gut barrier function. GOS have attracted significant interest from food industries for their versatility as a bioactive ingredient and in particular as a functional component of infant formulations. These oligosaccharides are produced in a kinetically-controlled reaction involving lactose transgalactosylation, being catalyzed by particular β-galactosidases of bacterial or fungal origin. Despite the well-established technology applied for GOS production, this process may still meet with technological challenges when employed at an industrial scale. The current review will cover relevant scientific literature on the beneficial physiological properties of GOS as a prebiotic for the infant gut microbiota, details of GOS structures, the associated reaction mechanism of β-galactosidase, and its (large-scale) production.

Evaluation of Probiotic Properties and Prebiotic Utilization Potential of Weissella paramesenteroides Isolated From Fruits

Weissella paramesenteroides has gained a considerable attention as bacteriocin and exopolysaccharide producers. However, potential of W. paramesenteroides to utilize different prebiotics is unexplored area of research. Fruits being vectors of various probiotics, five W. paramesenteroides strains, namely, FX1, FX2, FX5, FX9, and FX12, were isolated from different fruits. They were screened and selected based on their ability to survive at pH 2.5 and in 1.0% sodium taurocholate, high cell surface hydrophobicity, mucin adhesion, bile-induced biofilm formation, antimicrobial activity (AMA) against selected enteropathogens, and prebiotic utilization ability, implicating the functional properties of these strains. In vitro safety evaluation showed that strains were susceptible to antibiotics except vancomycin and did not harbor any virulent traits such as biogenic amine production, hemolysis, and DNase production. Based on their functionality, two strains FX5 and FX9 were selected for prebiotic utilization studies by thin layer chromatography (TLC) and short-chain fatty acids (SCFAs) production by high performance liquid chromatography. TLC profile evinced the ability of these two strains to utilize low molecular weight galactooligosaccharides (GOS) and fructooligosaccharides (FOS), as only the upper low molecular weight fractions were disappeared from cell-free-supernatants (CFS). Enhanced β-galactosidase activity correlated with galactose accumulation in residual CFS of GOS displayed GOS utilization ability. Both the strains exhibited AMA against E. coli and Staph. aureus and high SCFAs production in the presence of prebiotic, suggesting their synbiotic potential. Thus, W. paramesenteroides strains FX5 and FX9 exhibit potential probiotic properties with prebiotic utilization and can be taken forward to evaluate synergistic synbiotic potential in detail.

The metabolic profile of Bifidobacterium dentium reflects its status as a human gut commensal

BACKGROUND

Bifidobacteria are commensal microbes of the mammalian gastrointestinal tract. In this study, we aimed to identify the intestinal colonization mechanisms and key metabolic pathways implemented by Bifidobacterium dentium.

RESULTS

B. dentium displayed acid resistance, with high viability over a pH range from 4 to 7; findings that correlated to the expression of Na+/H+ antiporters within the B. dentium genome. B. dentium was found to adhere to human MUC2+ mucus and harbor mucin-binding proteins. Using microbial phenotyping microarrays and fully-defined media, we demonstrated that in the absence of glucose, B. dentium could metabolize a variety of nutrient sources. Many of these nutrient sources were plant-based, suggesting that B. dentium can consume dietary substances. In contrast to other bifidobacteria, B. dentium was largely unable to grow on compounds found in human mucus; a finding that was supported by its glycosyl hydrolase (GH) profile. Of the proteins identified in B. dentium by proteomic analysis, a large cohort of proteins were associated with diverse metabolic pathways, indicating metabolic plasticity which supports colonization of the dynamic gastrointestinal environment.

CONCLUSIONS

Taken together, we conclude that B. dentium is well adapted for commensalism in the gastrointestinal tract.