Bioengineered Wheat Arabinoxylan - Fostering Next-Generation Prebiotics Targeting Health-Related Gut Microbes

Dietary prebiotic fibers play an important role in modulating gut microbiota by enhancing the abundance of beneficial microorganisms and their bioactive metabolites. However, dietary fibers are a structurally heterogeneous class of polysaccharides, varying in molar mass, branching patterns, and monosaccharide composition, which could influence their utilization by various gut microorganisms. The present study aimed to investigate the effects of molar mass and chemical structure of wheat arabinoxylan fiber (AX) on the growth and metabolism of two key gut resident bacteria (Faecalibacterium prausnitzii and Lacticaseibacillus rhamnosus LGG), which are linked to human health. For this purpose, low, medium, and high molar masses of AX (LAX, MAX, and HAX, respectively) were modified with specific α-arabinofuranosidases to leave only singly substituted, only doubly substituted, or unsubstituted xylose units. Almost all the modified AX samples showed a better prebiotic score than unmodified AX for different molar masses. The modified LAX exhibited a better prebiotic effect than HAX and MAX. In addition, LAX, with doubly substituted xylose units, exhibited the highest prebiotic potential and SCFA production by both microorganisms. Furthermore, AX, either singly or doubly substituted, had a consistent impact on L. rhamnosus growth, whereas AX, with all arabinose residues removed, had a greater impact on F. prausnitzii. These findings support the potential of bioengineered AX as next-generation prebiotics targeting health-related gut microbes.

Fructooligosaccharides and galactooligosaccharides improve hepatic steatosis via gut microbiota-brain axis modulation

Studies have shown that gut dysbiosis is associated with the steatotic liver disease associated with metabolic dysfunction (MALSD) and its severity. This study evaluated the effects of two commercially available prebiotics fructooligosaccharides (FOS) and galactooligosaccharides(GOS) on hepatic adipogenesis, inflammation, and gut microbiota in high-fat diet-induced MALSD. The results indicated that FOS and GOS effectively reduced insulin resistance, hyperglycaemia, triglyceridemia, cholesterolaemia, and IL-1β serum levels. Moreover, FOS and GOS modulated the lipogenic (SREBP-1c, ACC, and FAS) and lipolytic (ATGL) signalling pathways, and reduced inflammatory markers such as p-NFκB-65, IL-6, iNOS, COX-2, TNF-α, IL-1β, and nitrotyrosine. FOS and GOS also enhanced the abundance of acetate producers' bacteria Bacteroides acidifaciens and Bacteroides dorei. FOS and GOS also induced positive POMC/GPR43 neurons at the arcuate nucleus, indicating hypothalamic signalling modulation. Our results suggest that FOS and GOS attenuated MALSD by reducing the hepatic lipogenic pathways and intestinal permeability through the gut microbiota-brain axis.

Characterization and prebiotic properties of pectin polysaccharide from Clausena lansium (Lour.) Skeels fruit

Pectins have proven to be advantageous for human health as they regulate beneficial microbial communities and enhance immunity. The fruit of Clausena lansium (Lour.) Skeels (Wampee), also referred to as "treasure in fruit", is rich in pectin polysaccharides. In this study, a homogalacturonan-type pectin (CCP2) with a molecular weight of 8.9 × 10⁴ Da and degree of esterification of 42.86% was isolated from Wampee fruit. The gut microbiota regulation and phagocytosis-enhancing properties of CCP2 were examined in vivo and in vitro, respectively. Oral administration of CCP2 dramatically decreased the abundance of Bacteroidetes and increased the abundance of Firmicutes in intestinal bacteria in mice. The content of short-chain fatty acids in the feces also significantly improved. Moreover, CCP2 exhibited excellent phagocytosis-enhancing activities on RAW 264.7 macrophages. These results suggested that CCP2 could be a potential gut microbiota regulator and phagocytosis-enhancer, which could be used in food products to promote health through beneficial manipulation of gut microbiota.

Molecular and Cellular Mechanisms Influenced by Postbiotics

In recent years, commensal bacteria colonizing the human body have been recognized as important determinants of health and multiple pathologic conditions. Among the most extensively studied commensal bacteria are the gut microbiota, which perform a plethora of functions, including the synthesis of bioactive products, metabolism of dietary compounds, and immunomodulation, both through attenuation and immunostimulation. An imbalance in the microbiota population, i.e., dysbiosis, has been linked to many human pathologies, including various cancer types and neurodegenerative diseases. Targeting gut microbiota and microbiome-host interactions resulting from probiotics, prebiotics, and postbiotics is a growing opportunity for the effective treatment of various diseases. As more research is being conducted, the microbiome field is shifting from simple descriptive analysis of commensal compositions to more molecular, cellular, and functional studies. Insight into these mechanisms is of paramount importance for understanding and modulating the effects that microbiota, probiotics, and their derivatives exert on host health.

Chickpea-Derived Prebiotic Substances Trigger Biofilm Formation by Bacillus subtilis

Chickpea-based foods are known for their low allergenicity and rich nutritional package. As an essential dietary legume, chickpea is often processed into milk or hummus or as an industrial source of protein and starch. The current study explores the feasibility of using the chickpea-derived prebiotic substances as a scaffold for growing Bacillus subtilis (a prospective probiotic bacterium) to develop synbiotic chickpea-based functional food. We report that the chickpea-derived fibers enhance the formation of the B. subtilis biofilms and the production of the antimicrobial pigment pulcherrimin. Furthermore, electron micrograph imaging confirms the bacterial embedding onto the chickpea fibers, which may provide a survival tactic to shield and protect the bacterial population from environmental insults. Overall, it is believed that chickpea-derived prebiotic substances provide a staple basis for developing functional probiotics and synbiotic food.

Effects of a Postbiotic and Prebiotic Mixture on Suckling Rats' Microbiota and Immunity

Human milk serves as a model for infant formula providing nutritional solutions for infants not able to receive enough mother’s milk. Infant formulas aim to mimic the composition and functionality of human milk by providing ingredients reflecting those of the latest human milk insights, such as prebiotics, probiotics and postbiotics. The aim of this study was to examine the effects of the supplementation with a postbiotic (Lactofidus^TM) and its combination with the prebiotics short-chain galactooligosaccharides (scGOS) and long-chain fructooligosaccharides (lcFOS) in a preclinical model of healthy suckling rats. Pups were supplemented daily with Lactofidus^TM (POST group) and/or scGOS/lcFOS (P+P and PRE groups, respectively). Body weight and fecal consistency were analyzed. At the end of the study, immunoglobulin (Ig) profile, intestinal gene expression, microbiota composition and short chain fatty acid (SCFA) proportion were quantified. The supplementation with all nutritional interventions modulated the Ig profile, but the prebiotic mixture and the postbiotic induced differential effects: whereas scGOS/lcFOS induced softer feces and modulated microbiota composition and SCFA profile, Lactofidus™ upregulated Toll-like receptors gene expression. The use of the combination of scGOS/lcFOS and Lactofidus™ showed the effects observed for the oligosaccharides separately, as well as showing a synergistic impact on animal growth. Thus, the combined use of both products seems to be a good strategy to modulate immune and microbial features in early life.

Brown Seaweed Sargassum siliquosum as an Intervention for Diet-Induced Obesity in Male Wistar Rats

The therapeutic potential of Sargassum siliquosum grown in Australian tropical waters was tested in a rat model of metabolic syndrome. Forty-eight male Wistar rats were divided into four groups of 12 rats and each group was fed a different diet for 16 weeks: corn starch diet (C); high-carbohydrate, high-fat diet (H) containing fructose, sucrose, saturated and trans fats; and C or H diets with 5% S. siliquosum mixed into the food from weeks 9 to 16 (CS and HS). Obesity, hypertension, dyslipidaemia, impaired glucose tolerance, fatty liver and left ventricular fibrosis developed in H rats. In HS rats, S. siliquosum decreased body weight (H, 547 ± 14; HS, 490 ± 16 g), fat mass (H, 248 ± 27; HS, 193 ± 19 g), abdominal fat deposition and liver fat vacuole size but did not reverse cardiovascular and liver effects. H rats showed marked changes in gut microbiota compared to C rats, while S. siliquosum supplementation increased gut microbiota belonging to the family Muribaculaceae. This selective increase in gut microbiota likely complements the prebiotic actions of the alginates. Thus, S. siliquosum may be a useful dietary additive to decrease abdominal and liver fat deposition.

A comprehensive review on the impact of β-glucan metabolism by Bacteroides and Bifidobacterium species as members of the gut microbiota

β-glucans are polysaccharides which can be obtained from different sources, and which have been described as potential prebiotics. The beneficial effects associated with β-glucan intake are that they reduce energy intake, lower cholesterol levels and support the immune system. Nevertheless, the mechanism(s) of action underpinning these health effects related to β-glucans are still unclear, and the precise impact of β-glucans on the gut microbiota has been subject to debate and revision. In this review, we summarize the most recent advances involving structurally different types of β-glucans as fermentable substrates for Bacteroidetes (mainly Bacteroides) and Bifidobacterium species as glycan degraders. Bacteroides is one of the most abundant bacterial components of the human gut microbiota, while bifidobacteria are widely employed as a probiotic ingredient. Both are generalist glycan degraders capable of using a wide range of substrates: Bacteroides spp. are specialized as primary degraders in the metabolism of complex carbohydrates, whereas Bifidobacterium spp. more commonly metabolize smaller glycans, in particular oligosaccharides, sometimes through syntrophic interactions with Bacteroides spp., in which they act as secondary degraders.

Postbiotics, Metabolic Signaling, and Cancer

Postbiotics are health-promoting microbial metabolites delivered as a functional food or a food supplement. They either directly influence signaling pathways of the body or indirectly manipulate metabolism and the composition of intestinal microflora. Cancer is the second leading cause of death worldwide and even though the prognosis of patients is improving, it is still poor in the substantial part of the cases. The preventable nature of cancer and the importance of a complex multi-level approach in anticancer therapy motivate the search for novel avenues of establishing the anticancer environment in the human body. This review summarizes the principal findings demonstrating the usefulness of both natural and synthetic sources of postbotics in the prevention and therapy of cancer. Specifically, the effects of crude cell-free supernatants, the short-chain fatty acid butyrate, lactic acid, hydrogen sulfide, and β-glucans are described. Contradictory roles of postbiotics in healthy and tumor tissues are highlighted. In conclusion, the application of postbiotics is an efficient complementary strategy to combat cancer.

Selective Utilization of the Human Milk Oligosaccharides 2'-Fucosyllactose, 3-Fucosyllactose, and Difucosyllactose by Various Probiotic and Pathogenic Bacteria

Prebiotic human milk oligosaccharides (HMOs) are found in human milk, which are not digested by infants but are metabolized by beneficial gut bacteria. We determined the ability of 57 bacterial strains within the Family Lactobacillaceae and genera Bifidobacterium and Bacteroides and potentially pathogenic bacteria to ferment the HMOs 2'-fucosyllactose, 3-fucosyllactose, and difucosyllactose. In addition, prebiotic galacto-oligosaccharides (GOS), lactose, fucose, and glucose were evaluated as carbon sources for these bacterial strains. Bacterial growth was monitored using the automatic Bioscreen C system. Only certain bifidobacteria, such as Bifidobacterium longum subsp. infantis and Bifidobacterium bifidum, as well as Bacteroides fragilis, Bacteroides vulgatus, and Bacteroides thetaiotaomicron utilized the studied HMOs as their sole carbon source, whereas almost all studied bacterial strains were able to utilize GOS, lactose, and glucose. The selectivity in utilization of HMOs by only certain bacteria can be advantageous by promoting beneficial microbes but not supporting the harmful pathogens in contrast to other less selective prebiotics.

Limiting the pathogenesis of Salmonella Typhimurium with berry phenolic extracts and linoleic acid overproducing Lactobacillus casei

The growing threat of emergent multidrug-resistant enteric bacterial pathogens, and their adopted virulence properties are directing to find alternative antimicrobials and/or development of dietaries that can improve host gut health and/or defense. Recently, we found that modified Lactobacillus casei (Lc + CLA) with increased production of conjugated linoleic acid has antimicrobial and other beneficial properties. Further, prebiotic alike products such as berry pomace extracts (BPEs), increase the growth of probiotics and inhibit the growth of certain bacterial pathogens. In this study, we evaluated the antibacterial effect of genetically modified Lc + CLA along with BPEs against major enteric pathogen Salmonella enterica serovar Typhimurium (ST). In mixed culture condition, the growth of ST was significantly reduced in the presence of Lc + CLA and/or BPEs. Bacterial cell-free cultural supernatant (CFCS) collected from wild-type Lc or modified Lc + CLA strains also inhibited the growth and survival of ST, and those inhibitory effects were enhanced in the presence of BPEs. We also found that the interaction of the pathogen with cultured host (HD-11 and INT-407) cells were also altered in the presence of either Lc or Lc + CLA strain or their CFCSs significantly. Furthermore, the relative expression of genes related to ST virulence and physicochemical properties of ST was altered by the effect of CFCSs of either Lc or Lc + CLA. These findings indicate that a diet containing synbiotic, specifically linoleic acid, over-produced Lc + CLA and prebiotic product BPEs, might have the potential to be effective in controlling ST growth and pathogenesis.

Microbial-Based and Microbial-Targeted Therapies for Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD), including Crohn's disease, ulcerative colitis, and pouchitis, are chronic, relapsing intestinal inflammatory disorders mediated by dysregulated immune responses to resident microbiota. Current standard therapies that block immune activation with oral immunosuppressives or biologic agents are generally effective, but each therapy induces a sustained remission in only a minority of patients. Furthermore, these approaches can have severe adverse events. Recent compelling evidence of a role of unbalanced microbiota (dysbiosis) driving immune dysfunction and inflammation in IBD supports the therapeutic rationale for manipulating the dysbiotic microbiota. Traditional approaches using currently available antibiotics, probiotics, prebiotics, and synbiotics have not produced optimal results, but promising outcomes with fecal microbiota transplant provide a proof of principle for targeting the resident microbiota. Rationally designed oral biotherapeutic products (LBPs) composed of mixtures of protective commensal bacterial strains demonstrate impressive preclinical results. Resident microbial-based and microbial-targeted therapies are currently being studied with increasing intensity for IBD primary therapy with favorable early results. This review presents current evidence and therapeutic mechanisms of microbiota modulation, emphasizing clinical studies, and outlines prospects for future IBD treatment using new approaches, such as LBPs, bacteriophages, bacterial function-editing substrates, and engineered bacteria. We believe that the optimal clinical use of microbial manipulation may be as adjuvants to immunosuppressive for accelerated and improved induction of deep remission and as potential safer solo approaches to sustained remission using personalized regimens based on an individual patient's microbial profile.

Citrus polymethoxyflavones attenuate metabolic syndrome by regulating gut microbiome and amino acid metabolism

Metabolic syndrome (MetS) is intricately linked to dysregulation of gut microbiota and host metabolomes. Here, we first find that a purified citrus polymethoxyflavone-rich extract (PMFE) potently ameliorates high-fat diet (HFD)-induced MetS, alleviates gut dysbiosis, and regulates branched-chain amino acid (BCAA) metabolism using 16S rDNA amplicon sequencing and metabolomic profiling. The metabolic protective effects of PMFE are gut microbiota dependent, as demonstrated by antibiotic treatment and fecal microbiome transplantation (FMT). The modulation of gut microbiota altered BCAA levels in the host serum and feces, which were significantly associated with metabolic features and actively responsive to therapeutic interventions with PMFE. Notably, PMFE greatly enriched the commensal bacterium Bacteroides ovatus, and gavage with B. ovatus reduced BCAA concentrations and alleviated MetS in HFD mice. PMFE may be used as a prebiotic agent to attenuate MetS, and target-specific microbial species may have unique therapeutic promise for metabolic diseases.

Resistant Starch is Actively Fermented by Infant Faecal Microbiota and Increases Microbial Diversity

In adults, fermentation of high amylose maize starch (HAMS), a resistant starch (RS), has a prebiotic effect. Were such a capacity to exist in infants, intake of RS might programme the gut microbiota during a critical developmental period. This study aimed to determine if infant faecal inocula possess the capacity to ferment HAMS or acetylated-HAMS (HAMSA) and characterise associated changes to microbial composition. Faecal samples were collected from 17 healthy infants at two timepoints: Preweaning and within 10 weeks of first solids. Fermentation was assessed using in vitro batch fermentation. Following 24 h incubation, pH, short-chain fatty acid (SCFA) production and microbial composition were compared to parallel control incubations. In preweaning infants, there was a significant decrease at 24 h in pH between control and HAMS incubations and a significant increase in the production of total SCFAs, indicating fermentation. Fermentation of HAMS increased further following commencement of solids. Fermentation of RS with weaning faecal inocula increased Shannon's diversity index (H) and was associated with increased abundance of Bifidobacterium and Bacteroides. In conclusion, the faecal inocula from infants is capable of RS fermentation, independent of stage of weaning, but introduction of solids increases this fermentation capacity. RS may thus function as a novel infant prebiotic.

Probiotics to prevent infantile colic

BACKGROUND

Infantile colic is typically defined as full-force crying for at least three hours per day, on at least three days per week, for at least three weeks. Infantile colic affects a large number of infants and their families worldwide. Its symptoms are broad and general, and while not indicative of disease, may represent a serious underlying condition in a small percentage of infants who may need a medical assessment. Probiotics are live microorganisms that alter the microflora of the host and provide beneficial health effects. The most common probiotics used are of Lactobacillus, Bifidobacterium and Streptococcus. There is growing evidence to suggest that intestinal flora in colicky infants differ from those in healthy infants, and it is suggested that probiotics can redress this balance and provide a healthier intestinal microbiota landscape. The low cost and easy availability of probiotics makes them a potential prophylactic solution to reduce the incidence and prevalence of infantile colic.

OBJECTIVES

To evaluate the efficacy and safety of prophylactic probiotics in preventing or reducing severity of infantile colic.

SEARCH METHODS

In January 2018 we searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, 10 other databases and two trials registers. In addition, we handsearched the abstracts of relevant meetings, searched reference lists, ran citation searches of included studies, and contacted authors and experts in the field, including the manufacturers of probiotics, to identify unpublished trials.

SELECTION CRITERIA

Randomised control trials (RCTs) of newborn infants less than one month of age without the diagnosis of infantile colic at recruitment. We included any probiotic, alone or in combination with a prebiotic (also known as synbiotics), versus no intervention, another intervention(s) or placebo, where the focus of the study was the effect of the intervention on infantile colic.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures of Cochrane.

MAIN RESULTS

Our search yielded 3284 records, and of these, we selected 21 reports for full-text review. Six studies with 1886 participants met our inclusion criteria, comparing probiotics with placebo. Two studies examined Lactobacillus reuteri DSM, two examined multi-strain probiotics, one examined Lactobacillus rhamnosus, and one examined Lactobacillus paracasei and Bifidobacterium animalis. Two studies began probiotics during pregnancy and continued administering them to the baby after birth.We considered the risk of bias for randomisation as low for all six trials; for allocation concealment as low in two studies and unclear in four others. All studies were blinded, and at low risk of attrition and reporting bias.A random-effects meta-analysis of three studies (1148 participants) found no difference between the groups in relation to occurrence of new cases of colic: risk ratio (RR) 0.46, 95% confidence interval (CI) 0.18 to 1.19; low-certainty evidence; I² = 72%.A random-effects meta-analysis of all six studies (1851 participants) found no difference between the groups in relation to serious adverse effects (RR 1.02, 95% CI 0.14 to 7.21; low-certainty evidence; I² not calculable (only four serious events for one comparison, two in each group: meconium plug obstruction, patent ductus arteriosus and neonatal hepatitis).A random-effects meta-analysis of three studies (707 participants) found a mean difference (MD) of -32.57 minutes per day (95% CI -55.60 to -9.54; low-certainty evidence; I² = 93%) in crying time at study end in favour of probiotics.A subgroup analysis of the most studied agent, Lactobacillus reuteri, showed a reduction of 44.26 minutes in daily crying with a random-effects model (95% CI -66.6 to -21.9; I² = 92%), in favour of probiotics.

AUTHORS' CONCLUSIONS

There is no clear evidence that probiotics are more effective than placebo at preventing infantile colic; however, daily crying time appeared to reduce with probiotic use compared to placebo. There were no clear differences in adverse effects.We are limited in our ability to draw conclusions by the certainty of the evidence, which we assessed as being low across all three outcomes, meaning that we are not confident that these results would not change with the addition of further research.

Microbe-metabolite-host axis, two-way action in the pathogenesis and treatment of human autoimmunity

The role of microorganism in human diseases cannot be ignored. These microorganisms have evolved together with humans and worked together with body's mechanism to maintain immune and metabolic function. Emerging evidence shows that gut microbe and their metabolites open up new doors for the study of human response mechanism. The complexity and interdependence of these microbe-metabolite-host interactions are rapidly being elucidated. There are various changes of microbial levels in models or in patients of various autoimmune diseases (AIDs). In addition, the relevant metabolites involved in mechanism mainly include short-chain fatty acids (SCFAs), bile acids (BAs), and polysaccharide A (PSA). Meanwhile, the interaction between microbes and host genes is also a factor that must be considered. It has been demonstrated that human microbes are involved in the development of a variety of AIDs, including organ-specific AIDs and systemic AIDs. At the same time, microbes or related products can be used to remodel body's response to alleviate or cure diseases. This review summarizes the latest research of microbes and their related metabolites in AIDs. More importantly, it highlights novel and potential therapeutics, including fecal microbial transplantation, probiotics, prebiotics, and synbiotics. Nonetheless, exact mechanisms still remain elusive, and future research will focus on finding a specific strain that can act as a biomarker of an autoimmune disease.

Microbiome and diabetes: Where are we now?

Alterations in the diversity or structure of gut microbiota known as dysbiosis, may affect metabolic activities, resulting in metabolic disorders, such as obesity and diabetes. The development of more sophisticated methods, such as metagenomics sequencing, PCR-denaturing gradient gel electrophoresis, microarrays and fluorescence in situ hybridization, has expanded our knowledge on gut microbiome. Dysbiosis has been related to increased plasma concentrations of gut microbiota-derived lipopolysaccharide (LPS), which triggers the production of a variety of cytokines and the recruitment of inflammatory cells. Metabolomics have demonstrated that butyrate and propionate suppress weight gain in mice with high fat diet-induced obesity, and acetate has been proven to reduce food intake in healthy mice. The role of prebiotics, probiotics, genetically modified bacteria and fecal microbiota transplantation, as potential therapeutic challenges for type 2 diabetes will be discussed in this review.

Prebiotics, Bone and Mineral Metabolism

Increasing interest in functional foods has driven discovery in the area of bioactive compounds. Prebiotics are non-digestible carbohydrate compounds that, when consumed, elicit health benefits and aid in the prevention and treatment of chronic diseases. While prebiotics have been shown to improve a number of chronic, inflammatory conditions, growing evidence exists for prebiotic effects on calcium metabolism and bone health. These novel dietary fibers have been shown to increase calcium absorption in the lower intestines of both preclinical and human models. Rodent models have also been imperative for understanding prebiotic effects on bone mineral density and measures of skeletal strength. Although fewer data are available for humans, bone-related prebiotic effects exist across the lifecycle, suggesting benefits for attainment of peak bone mass during adolescence and minimized bone resorption among postmenopausal women. These effects are thought to occur through prebiotic-microbe interactions in the large intestine. Current prebiotic mechanisms for improved mineral absorption and skeletal health include alterations in gut microbiota composition, production of short-chain fatty acids, altered intestinal pH, biomarker modification, and immune system regulation. While the majority of available data support improved mineral bioavailability, emerging evidence suggests alternate microbial roles and the presence of an intricate gut-bone signaling axis. Overall, the current scientific literature supports prebiotic consumption as a cost-effective and sustainable approach for improved skeletal health and/or fracture prevention. The goal of this review is to discuss both foundational and recent research in the area of prebiotics, mineral metabolism, and bone health.

Recent Technology Development for the Biosynthesis of Human Milk Oligosaccharide

BACKGROUND

Human milk oligosaccharide (HMO) is a third most abundant component in breast milk. HMOs are molecules naturally tailored to the need of an infant. They protect infants from diseases, foster healthy gastrointestinal systems, reinforce fledgling immune function, and promote early brain development. Supplement HMOs to infant formula, which lack this critical element, would substantially improve the function of formula. Overwhelming evidence also indicate that HMOs can be used for the treatment of arthritis and related autoimmune disease, and inhibition of bacteria adhesion or as potential prebiotics. The prospect of using HMO in these applications has stimulated worldwide interest in developing synthesis technology for these valuable products.

METHODS

As the quantities extracted from human milk are limited, and chemical synthesis methods are time-consuming, costly, and complex, biotechnological approach, involving either enzyme catalysis or metabolically engineered bacteria is preferred. In this review, we highlight the most recent advances in the synthesis technologies, as disclosed in patents and patent applications, and analyze these technologies against those reported in literatures.

CONCLUSION

Significant progress has been made over the past decade, especially in whole-cell biocatalysis for smaller HMOs. Significant challenges remain for larger and more complex HMOs.

High Antioxidant Action and Prebiotic Activity of Hydrolyzed Spent Coffee Grounds (HSCG) in a Simulated Digestion-Fermentation Model: Toward the Development of a Novel Food Supplement

Spent coffee grounds are a byproduct with a large production all over the world. The aim of this study was to explore the effects of a simulated digestion-fermentation treatment on hydrolyzed spent coffee grounds (HSCG) and to investigate the antioxidant properties of the digestion and fermentation products in the human hepatocellular carcinoma HepG2 cell line. The potentially bioaccessible (soluble) fractions exhibited high chemoprotective activity in HepG2 cells against oxidative stress. Structural analysis of both the indigestible (insoluble) and soluble material revealed partial hydrolysis and release of the lignin components in the potentially bioaccessible fraction following simulated digestion-fermentation. A high prebiotic activity as determined from the increase in Lactobacillus spp. and Bifidobacterium spp. and the production of short-chain fatty acids (SCFAs) following microbial fermentation of HSCG was also observed. These results pave the way toward the use of HSCG as a food supplement.

Potential prebiotic properties of cashew apple (Anacardium occidentale L.) agro-industrial byproduct on Lactobacillus species

BACKGROUND

The prebiotic effects of a cashew apple (Anacardium occidentale L.) agro-industrial byproduct powder (CAP) on different potentially probiotic Lactobacillus strains, namely Lactobacillus acidophilus LA-05, Lactobacillus casei L-26 and Lactobacillus paracasei L-10, were assessed using in vitro experimental models. Accordingly, the growth of the Lactobacillus strains when cultivated in a broth containing CAP (20 or 30 g L^-1 ), glucose (20 g L^-1 ) or fructooligosaccharides (FOS) (20 g L^-1 ) was monitored over 48 h; the prebiotic activity scores of CAP were determined; and the changes in pH values, production of organic acids and consumption of sugars in growth media were verified.

RESULTS

During the 48-h cultivation, similar viable cell counts were observed for the Lactobacillus strains grown in the different media tested. The CAP presented positive prebiotic activity scores toward all the tested Lactobacillus strains, indicating a desirable selective fermentable activity relative to enteric organisms. The cultivation of the Lactobacillus strains in broth containing glucose, FOS or CAP resulted in high viable cell counts, a decreased pH, the production of organic acids and the consumption of sugars over time, revealing intense bacterial metabolic activity.

CONCLUSION

The CAP exerts potential prebiotic effects on different potentially probiotic Lactobacillus strains and should be an added-value ingredient for the food industry. © 2017 Society of Chemical Industry.

In Situ β-Glucan Fortification of Cereal-Based Matrices by Pediococcus parvulus 2.6: Technological Aspects and Prebiotic Potential

Bacterial exopolysaccharides produced by lactic acid bacteria are of increasing interest in the food industry, since they might enhance the technological and functional properties of some edible matrices. In this work, Pediococcus parvulus 2.6, which produces an O2-substituted (1,3)-β-d-glucan exopolysaccharide only synthesised by bacteria, was proposed as a starter culture for the production of three cereal-based fermented foods. The obtained fermented matrices were naturally bio-fortified in microbial β-glucans, and used to investigate the prebiotic potential of the bacterial exopolysaccharide by analysing the impact on the survival of a probiotic Lactobacillus plantarum strain under starvation and gastrointestinal simulated conditions. All of the assays were performed by using as control of the P. parvulus 2.6's performance, the isogenic β-glucan non-producing 2.6NR strain. Our results showed a differential capability of P. parvulus to ferment the cereal flours. During the fermentation step, the β-glucans produced were specifically quantified and their concentration correlated with an increased viscosity of the products. The survival of the model probiotic L. plantarum WCFS1 was improved by the presence of the bacterial β-glucans in oat and rice fermented foods under starvation conditions. The probiotic bacteria showed a significantly higher viability when submitted to a simulated intestinal stress in the oat matrix fermented by the 2.6 strain. Therefore, the cereal flours were a suitable substrate for in situ bio-fortification with the bacterial β-glucan, and these matrices could be used as carriers to enhance the beneficial properties of probiotic bacteria.

An In Vitro Approach to Study Effects of Prebiotics and Probiotics on the Faecal Microbiota and Selected Immune Parameters Relevant to the Elderly

The aging process leads to alterations of gut microbiota and modifications to the immune response, such changes may be associated with increased disease risk. Prebiotics and probiotics can modulate microbiome changes induced by aging; however, their effects have not been directly compared. The aim of this study was to use anaerobic batch culture fermenters to assess the impact of various fermentable carbohydrates and microorganisms on the gut microbiota and selected immune markers. Elderly volunteers were used as donors for these experiments to enable relevance to an aging population. The impact of fermentation supernatants on immune markers relevant to the elderly were assessed in vitro. Levels of IL-1β, IL-6, IL-8, IL-10 and TNF-α in peripheral blood mononuclear cell culture supernatants were measured using flow cytometry. Trans-galactooligosaccharides (B-GOS) and inulin both stimulated bifidobacteria compared to other treatments (p<0.05). Fermentation supernatants taken from faecal batch cultures supplemented with B-GOS, inulin, B. bifidum, L. acidophilus and Ba. coagulans inhibited LPS induced TNF-α (p<0.05). IL-10 production, induced by LPS, was enhanced by fermentation supernatants from faecal batch cultures supplemented with B-GOS, inulin, B. bifidum, L. acidophilus, Ba. coagulans and Bac. thetaiotaomicron (p<0.05). To conclude, prebiotics and probiotics could lead to potentially beneficial effects to host health by targeting specific bacterial groups, increasing saccharolytic fermentation and decreasing inflammation associated with aging. Compared to probiotics, prebiotics led to greater microbiota modulation at the genus level within the fermenters.

Probiotics and prebiotics in ulcerative colitis

The intestinal microbiota is one of the key players in the etiology of ulcerative colitis. Manipulation of this microflora with probiotics and prebiotics is an attractive strategy in the management of ulcerative colitis. Several intervention studies for both the induction and maintenance of remission in ulcerative colitis patients have been performed. Most of these studies evaluated VSL#3 or E. Coli Nissle 1917 and in general there is evidence for efficacy of these agents for induction and maintenance of remission. However, studies are frequently underpowered, lack a control group, and are very heterogeneous investigating different probiotic strains in different study populations. The absence of well-powered robust randomized placebo-controlled trials impedes the widespread use of probiotics and prebiotics in ulcerative colitis. However, given the promising results that are currently available, probiotics and prebiotics may find their way to the treatment algorithm for ulcerative colitis in the near future.

The current place of probiotics and prebiotics in the treatment of pouchitis

Pouchitis is a common complication in patients undergoing restorative proctocolectomy for ulcerative colitis. Therapeutic attempts include manipulations of pouch flora composition. In this review, we bring together the evidence supporting the use of probiotics and prebiotics in pouchitis patients, to clarify the place of these treatments in current therapeutic regimens.

In Vitro Fermentation of Xylooligosaccharides Produced from Miscanthus × giganteus by Human Fecal Microbiota

Purified xylooligosaccharides from Miscanthus × giganteus (M×G XOS) were used in an in vitro fermentation experiment inoculated with human fecal microbiota. A commercial XOS product and pectin were used as controls. Decreases in pH by 2.3, 2.4, and 2.0 units and production of short-chain fatty acids (SCFA; acetic acid, 7764.2, 6664.1, and 6387.9 μmol/g; propionic acid, 1006.7, 1089.5, and 661.5 μmol/g; and butyric acid, 955.5, 1252.9, and 917.7 μmol/g) were observed in M×G XOS, commercial XOS, and pectin medium after 12 h of fermentation, respectively. Titers of Bifidobacterium spp., Lactobacillus spp., and Escherichia coli increased when fed all three substrates as monitored by qPCR. There was no significant trend for Clostridium perfringens. During fermentation, M×G XOS was statistically equivalent in performance to the commercial XOS sample as measured by culture acidification and growth of health-promoting bacteria and resulted in the highest SCFA production among the three substrates.

Prebiotic Effects of Agave salmiana Fructans in Lactobacillus acidophilus and Bifidobacterium lactis Cultures

Agave salmiana is a fructan rich species that is widely distributed in Mexico. The aim of this investigation was to extract the fructans of A. salmiana and evaluate their prebiotic effect in 48 hours in vitro cultures of Bifidobacterium lactis and Lactobacillus acidophilus and to compare this effect with other available fructan sources. A significant difference in pH, optical density and biomass was found in the cultures depending on the source of fructans and the type of bacteria. It was possible to determine a dose-response effect of the A. salmiana fructans and the growth of the studied strains.

Production, Purification, and in Vitro Evaluation of the Prebiotic Potential of Arabinoxylooligosaccharides from Brewer's Spent Grain

Brewer's spent grain (BSG) samples were subjected to a two-step aqueous processing (starch extraction and autohydrolysis) in order to assess their potential as a raw material for obtaining a mixture of arabinoxylooligosaccharides (AXOS) suitable to be use as prebiotics for elderly. After hydrothermal treatment, the liquors were refined by a sequence of purification and conditioning steps including membrane filtration, enzymatic hydrolysis, and ion exchange. The presence of both substituted (degree of polimerization (DP) = 2-10) and unsubstituted (DP = 2-16) oligosaccharides made up of xylose and arabinose (AXOS) were confirmed in purified mixtures (in which total OS content = 84% w/w) by using chromatographic techniques and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Finally, AXOS were evaluated for their prebiotic activity by in vitro fermentation assays using fecal inocula from elderly people, demonstrating that AXOS were slightly better substrates than FOS, in terms of bacterial population shifts as in the production of SCFA.

Influence of diet on gut microbiota, inflammation and type 2 diabetes mellitus. First experience with macrobiotic Ma-Pi 2 diet

Type 2 diabetes mellitus (T2DM) is a complex disorder influenced by both genetic and environmental factors. Recent studies have suggested that an imbalance of the intestinal microbiota may be involved in the development of several human diseases, including obesity and T2DM. The main regulators of the intestinal microbiota are age, ethnicity, the immune system and diet. A high-fat diet may induce dysbiosis, which can result in a low-grade inflammatory state, obesity and other metabolic disorders. Adding prebiotics to the diet may reduce inflammation, endotoxaemia and cytokine levels as well as improving insulin resistance and glucose tolerance. The administration of prebiotics such as fermentable dietary fibres, promotes glucagon-like peptide 1 and peptide YY (anorexigenic) and decreases ghrelin (orexigenic). In a recent 21-day, intervention study in patients with T2DM, the effect of using the macrobiotic Ma-Pi 2 diet was investigated. Results suggested that it could induce a significant improvement in fasting blood glucose, plasma lipid fractions, plasma insulin and homeostasis. It is therefore possible that a diet rich in prebiotics and probiotics can play a role in T2DM management, probably due to positive intestinal microbiota modulation. However, this must be demonstrated by larger studies including randomized controlled trials that measure indicators of inflammation.

[The parietal intestinal microflora in patients with chronic pancreatitis]

The article presents the results of the proximal small intestine parietal microbiocenosis research in patients with chronic pancreatitis by polymerase chain reaction in real time. The study includes an assessment of the pharmacological correction's efficiency in this category of patients.

From the gastrointestinal tract (GIT) to the kidneys: live bacterial cultures (probiotics) mediating reductions of uremic toxin levels via free radical signaling

A host of compounds are retained in the body of uremic patients, as a consequence of progressive renal failure. Hundreds of compounds have been reported to be retention solutes and many have been proven to have adverse biological activity, and recognized as uremic toxins. The major mechanistic overview considered to contribute to uremic toxin overload implicates glucotoxicity, lipotoxicity, hexosamine, increased polyol pathway activity and the accumulation of advanced glycation end-products (AGEs). Until recently, the gastrointestinal tract (GIT) and its associated micro-biometabolome was a neglected factor in chronic disease development. A systematic underestimation has been to undervalue the contribution of GIT dysbiosis (a gut barrier-associated abnormality) whereby low-level pro-inflammatory processes contribute to chronic kidney disease (CKD) development. Gut dysbiosis provides a plausible clue to the origin of systemic uremic toxin loads encountered in clinical practice and may explain the increasing occurrence of CKD. In this review, we further expand a hypothesis that posits that environmentally triggered and maintained microbiome perturbations drive GIT dysbiosis with resultant uremia. These subtle adaptation responses by the GIT microbiome can be significantly influenced by probiotics with specific metabolic properties, thereby reducing uremic toxins in the gut. The benefit translates to a useful clinical treatment approach for patients diagnosed with CKD. Furthermore, the role of reactive oxygen species (ROS) in different anatomical locales is highlighted as a positive process. Production of ROS in the GIT by the epithelial lining and the commensal microbe cohort is a regulated process, leading to the formation of hydrogen peroxide which acts as an essential second messenger required for normal cellular homeostasis and physiological function. Whilst this critical review has focused on end-stage CKD (type 5), our aim was to build a plausible hypothesis for the administration of probiotics with or without prebiotics for the early treatment of kidney disease. We postulate that targeting healthy ROS production in the gut with probiotics may be more beneficial than any systemic antioxidant therapy (that is proposed to nullify ROS) for the prevention of kidney disease progression. The study and understanding of health-promoting probiotic bacteria is in its infancy; it is complex and intellectually and experimentally challenging.

Different human gut models reveal the distinct fermentation patterns of Arabinoxylan versus inulin

Different in vitro models have been developed to assess how food compounds affect the human gut microbiota. Using two such models (SHIME(R) and TIM-2), we compared how long-chain arabinoxylan (LC-AX), a wheat-derived potentially prebiotic fiber, and inulin (IN), a well-established prebiotic compound, modulate SCFA production and bifidobacteria composition. While both the SHIME and TIM-2 differ in experimental design, they both demonstrated that LC-AX and IN specifically increased the health-promoting metabolites propionate and butyrate, respectively. Furthermore, LC-AX stimulated Bifidobacterium longum, while IN stimulated other bifidobacteria including Bifidobacterium adolescentis. The SHIME experiment also revealed that effects of LC-AX were more persistent during the 2-week wash-out period. These results confirm a recent in vivo study, during which humanized rats were treated with the same LC-AX/IN. In conclusion, results from different human gut models suggest that, besides IN, LC-AX are promising prebiotic candidates with high specificity toward Bifidobacterium longum and a selective propionate increase.

Functional metagenomics reveals novel pathways of prebiotic breakdown by human gut bacteria

The human intestine hosts a complex bacterial community that plays a major role in nutrition and in maintaining human health. A functional metagenomic approach was used to explore the prebiotic breakdown potential of human gut bacteria, including non-cultivated ones. Two metagenomic libraries, constructed from ileum mucosa and fecal microbiota, were screened for hydrolytic activities on the prebiotic carbohydrates inulin, fructo-oligosaccharides, xylo-oligosaccharides, galacto-oligosaccharides and lactulose. The DNA inserts of 17 clones, selected from the 167 hits that were identified, were pyrosequenced in-depth, yielding in total 407, 420 bp of metagenomic DNA. From these sequences, we discovered novel prebiotic degradation pathways containing carbohydrate transporters and hydrolysing enzymes, for which we provided the first experimental proof of function. Twenty of these proteins are encoded by genes that are also present in the gut metagenome of at least 100 subjects, whatever are their ages or their geographical origin. The sequence taxonomic assignment indicated that still unknown bacteria, for which neither culture conditions nor genome sequence are available, possess the enzymatic machinery to hydrolyse the prebiotic carbohydrates tested. The results expand the vision on how prebiotics are metabolized along the intestine, and open new perspectives for the design of functional foods.

[Characteristics of collagen's material bifidogenic properties]

It is still essential to search for new, available food ingredients with bifidogenic effect, to study their safety, efficacy and production effectiveness upon the creation of functional foods. The review considers protein products such as collagens and their hydrolyzates, which are used in culture mediums as growth factor. They are treated, besides carbohydrate prebiotics, as potential bifidogenic nutrients. Collagen hydralyzates contain all amino acids, required for bifidobacteria growth. That is why it is considered essential to provide control over its biosafety. However, recyclable materials of animal origin are included into a list of Specific Risk Materials of prion disease agents transmitting. Collagen hydralyzates are preserved up to distal intestine parts. This fact approximates their qualities to oligosaccharids' type of prebiotic food fibers, related to the lack of absorption and hydrolytic stability. The additional study of mechanisms of bifidobacteria's forcing is required. It can be made at the expense of the modification of the albuminous cell metabolism during the collagen hydralyzats' unilization.

The influence of selected prebiotics on the growth of lactic acid bacteria for bio-yoghurt production

BACKGROUND

Prebiotics are a category of nutritional com-pounds grouped together, not necessarily by structural similarities, but by ability to promote the growth of spe-cific beneficial (probiotic) gut bacteria. Fructooligosaccharides (FOS) and inulin are among the most famous prebiotic compounds. In order to improve viability of probiotic bacteria during storage, fermented food should be supplemented with prebiotics.

MATERIAL AND METHODS

Yoghurts were produced from skimmed milk powder and prebiotics (FOS, inulin or resistant starch), which were added at concentrations of 1%, 2% and 3%. Yoghurts were stored in +4°C for three weeks. Every week each kind of fermented drink was examined in order to check the growth of lactic acid bacteria. Apparent viscosity and texture of bio-yoghurt were determinated during refrigerated storage.

RESULTS

The FOS and inulin addition to yoghurt caused an increase in the numbers of all bacteria in comparison to control yoghurt obtained without addition of prebiotics. The viable counts of Str. thermophilus, Lb. acidophilus and Bifidobacterium sp. when 1% of FOS was added to yoghurt were about 9 log cfu/g, 7.8 log cfu/g and 7.7 log cfu/g, respectively. In the presence of 1% of inulin, streptococci and bifidobacteria reached the growth at the level 8.8 log cfu/g and 7.5 respectively. Hardness and adhesiveness of yoghurt obtained with addition resistant starch increased systematically during 21 days of refrigerated storage.

CONCLUSIONS

The numbers of lactic acid bacteria in obtained bio-yoghurts were sufficient in 97% of samples (10(6)-10(9) cfu/g) according to FAO/WHO protocols. Generally, viability of bacteria was sufficient for 14 days and then their numbers decreased but usually not below 10(6) cfu/g. Prebiotics as FOS and inulin added to bio-yoghurt exhibited stimulatory effect on growth Lb. acidophilus and Bifidobacterium sp. Addition of prebiotics caused an increase in apparent viscosity and hardness (in case of FOS) and decrease in syneresis of obtained bio-yoghurts.