Galacto-oligosaccharides Research Articles

Invited review: Properties of β-galactosidases derived from Lactobacillaceae species and their capacity for galacto-oligosaccharide production

β-galactosidase (enzymatic class 3.2.1.23) is one of the dairy industry's most important and widely used enzymes. The enzyme is part of a large family known to catalyze hydrolysis and transglycosylation reactions. Its hydrolytic activity is commonly used to decrease lactose content in dairy products, while its transglycosylase activity has recently been used to synthesize galacto-oligosaccharides (GOS). During the past couple of years, researchers have focused on studying β-galactosidase isolated and purified from lactic acid bacteria. This review will focus on β-galactosidase purified and characterized from what used to be the Lactobacillus genera. Furthermore, particular emphasis is given to its kinetics, biochemical characteristics, GOS production, market, and utilization by Lactobacilllaceae species.

Efficacy assessment of prebiotic enriched camel milk along with various prebiotic combinations against metabolic syndrome using animal model

Metabolic syndrome (MetS) is a public health concern even in apparently healthy individuals. This study was conducted with the main objective to evaluate the potential role of prebiotic enriched camel milk (PECM) as a functional food, against different biomarkers of MetS in comparison to fresh camel milk (CM) and other prebiotic sources, i.e., chicory root powder (CRP) and galacto-oligosaccharides (GOS) in rat’s model. The MetS was induced through a high-fat diet and streptozotocin. The PECM, CM, CRP, and GOS were fed to rats for 8 weeks, and different biochemical parameters were measured on baseline (0th day), 20th day, and 40th day. Prebiotics were able to significantly reduce the concentration of low-density lipoprotein, triglycerides, total cholesterol, and glucose compared to the control group with PECM being the most effective of all groups, whereas liver enzymes (ALT, AST, and AP) were significantly reduced and antioxidants improved by CM and PECM than other prebiotics and control. Histopathology results revealed improvement in degeneration and hydropic atrophies in the hepatocytes of the treatment group. It is concluded that PECM is effective in the management of MetS biomarkers and can improve the parameters of hyperlipidemia, liver enzymes, antioxidants, and glycemic control.

Effect of prebiotics on thermally acclimatized lactobacilli cultures and their application as synbiotics in RTD fruit drinks.

In this study, the effect of prebiotics such as fructooligosaccharides (FOS), galactooligosaccharides (GOS), isomaltooligosaccharides (IMO), and inulin on the probiotic biomass and its probiotic properties were studied for thermally acclimatized Lactobacillus helveticus (H-45) and Lacticaseibacillus casei N (N-45) strains at 45℃ using adaptive laboratory evolution method. Among the prebiotics studied, GOS was found to be more suitable for synbiotic preparation. The tolerance of lactobacilli cultures H-45 and N-45 in the presence of acid and bile were 4.79 and 8.60% and 2.84 and 4.65% higher than their wild-type strains (H-37 and N-37). Similarly, H-45 and N-45 showed an increase in survivability of 5.29 and 8.63% under simulated gastric conditions and 9.21 and 7.70% under simulated intestinal conditions than H-37 and N-37. Propionic acid yield increased by 0.65-fold in N-45 compared to N-37 in the presence of GOS as a prebiotic, whereas H-37 showed 0.26-fold higher propionic acid production than H-45. Thermally acclimatized strain N-45 showed better survivability under stress conditions than H-45. The synbiotic combination of N45 + GOS was spray-dried using corn starch (CS) as carrier material to obtain spray-dried synbiotic powder (N45 + CS + GOS). This synbiotic powder was added to the ready-to-drink (RTD) fruit drinks prepared from five fruit-flavoured squashes (pineapple, orange, grape, mango, and lemon ginger). The varied amounts of added synbiotic powder did not significantly alter the physicochemical properties of the fruit drinks. Hence, synbiotic formulation N45 + GOS + CS may find application in developing various functional foods.

A Narrative Review of Human Clinical Trials to Improve Lactose Digestion and Tolerance by Feeding Bifidobacteria or Galacto-Oligosacharides.

Supplementation with the probiotic Bifidobacterium and prebiotic galacto-oligosaccharides (GOS) could improve gut health and benefit lactose intolerant individuals. A narrative review was conducted to identify human clinical trials that evaluated lactose digestion and/or tolerance in response to consumption of Bifidobacterium, GOS, or both. A total of 152 studies on Bifidobacterium and GOS or both were published between 1983 and 2022. Out of the 152 studies, 20 were human clinical trials conducted in lactose intolerant subjects; 8 studies were conducted with Bifidobacterium supplementation and 3 studies involved GOS supplementation. Five studies reported favorable outcomes of Bifidobacterium supplementation in managing lactose intolerance (LI). Similarly, three studies reported favorable outcomes with GOS supplementation. The other three studies reported neutral outcomes. In conclusion, most studies reported a favorable effect of Bifidobacterium and GOS on managing the symptoms of LI. No study has examined the effects of combined supplementation with Bifidobacterium and GOS in lactose intolerant subjects. Future research could examine if co-supplementation with Bifidobacterium and GOS is a more effective strategy to reduce the dairy discomfort in LI individuals.

Identification and Characterization of a Potential Probiotic, Clostridium butyricum G13, Isolated from the Intestine of the Mud Crab (Scylla paramamosain).

The butyrate-producing bacterium Clostridium butyricum has been proven to be important in improving the growth and health benefits of aquatic animals. In this study, C. butyricum G13 was isolated for the first time from the gut of the mud crab (Scylla paramamosain). The results of this study showed that C. butyricum G13 could produce a high concentration of butyric acid and grow well in a wide range of pHs (4 to 9) and NaCl (1 to 2.5%) and bile salt (0.2 to 1.0%) concentrations. In vitro characterization revealed that C. butyricum G13 is a Gram-positive and gamma-hemolytic bacterium sensitive to most antibiotics and shows hydrophobicity and the capacity to degrade starch. In vitro fermentation using mud crab gut contents showed that C. butyricum G13 alone or in combination with galactooligosaccharides (GOS) and/or resistant starch (RS) significantly increased butyric acid production and beneficially affected the abundance and diversity of intestinal microbiota. In addition, C. butyricum G13 can improve the survival rate of mud crabs and effectively maintain the normal structure of gut morphology after infection with Vibrio parahaemolyticus. In conclusion, C. butyricum G13 can be considered a potential probiotic that improves the immune capacity and confers health benefits on mud crabs. IMPORTANCE With the development of society, more and more aquatic animals are demanded. Intensification in the aquaculture scale is facing problems, such as disease outbreaks, eutrophication of water bodies, and misuse of antibiotics. Among these challenges, disease outbreak is the most important factor directly affecting aquaculture production. It is crucial to explore new approaches effective for the prevention and control of diseases. Probiotics have been widely used in aquaculture and have shown beneficial effects on the host. In this study, the butyrate-producing bacterium Clostridium butyricum G13 was isolated for the first time from the intestine of the mud crab through in vitro fermentation. The bacterium has probiotic properties and changes the gut microbiota to be beneficial to hosts in vitro as well as protecting hosts from Vibrio parahaemolyticus infection in vivo. The outcomes of this study indicate that C. butyricum G13 can be used as a potential probiotic in mud crab aquaculture.

Laxative effect of prebiotics in chronic constipation: Mechanisms of action

Constipation is a condition that affects a consistent part of the general population, with increasing numbers of incidence worldwide. Its causes can be attributed to several factors. One of these factors (and one of the most relevant causes) is dietary choices. For instance, poor nutrition habits have been shown to adversely affect the function of the digestive tract, eliciting abnormal physiological responses that might lead to constipation. Prebiotics are specialized types of fermentable fibres which have been hypothesised to play a beneficial role in the treatment of chronic idiopathic constipation. Fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS) and inulin are the most common types of prebiotics. There are several studies to demonstrate that prebiotics have many interactions with the bowel and its movements, thus they are potentially beneficial in the treatment of chronic idiopathic constipation. Some prebiotics can retain water and therefore increase stool mass and viscosity, making the passage of faeces through the gastrointestinal tract easier. In addition, prebiotics can feed the probiotic bacteria (the body’s “good” bacteria that synergistically live in the digestive tract), and the fermentation of prebiotics by the probiotic bacteria leads to the production of short-chain fatty acids (SCFAs). SCFA synthesis through prebiotic fermentation has been shown to improve gastrointestinal function and bowel movement. Moreover, prebiotic fermentation in the colon might trigger both immunomodulatory responses and the production of neurotransmitters that elicit stronger contractility in the colon. Prebiotic fermentation from the gut microbiota might trigger the release of neurotransmitters that interact with the central nervous system (CNS) and enteric nervous system (ENS). These bacterial neuromodulators directly affect the digestive nerve terminals, eliciting responses from the digestive tract that result in a faster and easier defaecation. Besides the existing studies that describe the roles of prebiotics in gut health and motility, their beneficial role has not yet been fully understood and proven, thus further research is needed on the topic.

Effects of Administration of Prebiotics Alone or in Combination with Probiotics on In Vitro Fermentation Kinetics, Malodor Compound Emission and Microbial Community Structure in Swine

The objective of this study was to evaluate the effect of Lactobacillus amylovorus, L. plantarum, galacto-oligosaccharide (GOS) and their synbiotic formulations on pH, volatile fatty acids (VFA), malodor, and microbial ecological profiles through a 24-h in vitro fermentation model. Inclusion of GOS alone and in synbiotic combination with either probiotic resulted in consistently lower pH and higher total gas volumes at 12 and 24 h of incubation. Notably, concentrations of odorous compounds (hydrogen sulfide, H2S and methyl mercaptan, CH3SH) in the total gas produced were significantly lower in these GOS-containing treatments relative to the controls and probiotic-only-treated groups. However, although ammonia showed an initial relative reduction at 12 h, concentrations did not differ among treatments at 24 h. Further, the GOS-containing treatments had remarkably higher total and individual VFAs, including acetate, propionate, and butyrate, relative to controls and the probiotic-only treatments. Analysis of microbial composition and diversity showed clustering of GOS-containing treatments away from the controls and probiotic-only treatments at 12 and 24 h of incubation. Our study suggests that GOS supplementation (alone or in combination with L. amylovorus or L. plantarum probiotic strains) has the potential to increase VFA production in the swine gut while lowering emissions of malodorous compounds, except ammonia, in their manure.

Prebiotics modulate the microbiota-gut-brain axis and ameliorate cognitive impairment in APP/PS1 mice.

Prebiotics, including fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS), stimulate beneficial gut bacteria and may be helpful for patients with Alzheimer's disease (AD). This study aimed to compare the effects of FOS and GOS, alone or in combination, on AD mice and to identify their underlying mechanisms. Six-month-old APP/PS1 mice and wild-type mice were orally administered FOS, GOS, FOS + GOS or water by gavage for 6weeks and then subjected to relative assays, including behavioral tests, biochemical assays and 16S rRNA sequencing. Through behavioral tests, we found that GOS had the best effect on reversing cognitive impairment in APP/PS1 mice, followed by FOS + GOS, while FOS had no effect. Through biochemical techniques, we found that GOS and FOS + GOS had effects on multiple targets, including diminishing Aβ burden and proinflammatory IL-1β and IL-6 levels, and changing the concentrations of neurotransmitters GABA and 5-HT in the brain. In contrast, FOS had only a slight anti-inflammatory effect. Moreover, through 16S rRNA sequencing, we found that prebiotics changed composition of gut microbiota. Notably, GOS increased relative abundance of Lactobacillus, FOS increased that of Bifidobacterium, and FOS + GOS increased that of both. Furthermore, prebiotics downregulated the expression levels of proteins of the TLR4-Myd88-NF-κB pathway in the colons and cortexes, suggesting the involvement of gut-brain mechanism in alleviating neuroinflammation. Among the three prebiotics, GOS was the optimal one to alleviate cognitive impairment in APP/PS1 mice and the mechanism was attributed to its multi-target role in alleviating Aβ pathology and neuroinflammation, changing neurotransmitter concentrations, and modulating gut microbiota.

Prebiotics for depression: how does the gut microbiota play a role?

Depression, a mood disorder characterized by persistent feelings of sadness and aversion to activity that can interfere with daily life, is a condition of great concern. Prebiotics, which are non-digestible substances selectively utilized by host microorganisms for health benefits, have gained attention for their potential to improve overall wellness and alleviate various disorders including depression. This study aims to review clinical trials utilizing carbohydrate-type prebiotics such as inulin-type fructans, galactooligosaccharides (GOS), human milk oligosaccharides, resistant starch, prebiotic phytochemicals including epigallocatechin gallate (EGCG), chlorogenic acids, resveratrol, and prebiotic lipids (n-3 polysaturated fatty acids) to determine their effects on depression. Our findings suggest that GOS at a daily dosage of 5 g and eicosapentaenoic acid at or less than 1 g can effectively mitigate depressive symptoms. While EGCG exhibits potential antidepressant properties, a higher dosage of 3 g/d may be necessary to elicit significant effects. The plausible mechanisms underlying the impact of prebiotics on depression include the synthesis of neurotransmitters, production of short-chain fatty acids, and regulation of inflammation.

Fructooligosaccharide (FOS) and Galactooligosaccharide (GOS) Improve Neuroinflammation and Cognition By Up-regulating IRS/PI3K/AKT Signaling Pathway in Diet-induced Obese Mice.

Increasing evidence has indicated that prebiotics as an alternative treatment for neuropsychiatric diseases. This study evaluated the prebiotics Fructooligosaccharides (FOS) and Galactooligosaccharides (GOS) on the modulation of neuroinflammation and cognition in an experimental model of mice high-fat diet fed. Initially, mice were distributed in the following groups: (A) control standard diet (n = 15) and (B) HFD for 18 weeks (n = 30). In the 13th week, the mice were later divided into the following experimental groups: (A) Control (n = 15); (B) HFD (n = 14); and (C) HFD + Prebiotics (n = 14). From the 13th week, the HFD + Prebiotics group received a high-fat diet and a combination of FOS and GOS. In the 18th week, all animals performed the T-maze and Barnes Maze, and were later euthanized. Biochemical and molecular analyzes were performed to assess neuroinflammation, neurogenesis, synaptic plasticity, and intestinal inflammation. Mice fed HFD had higher blood glucose, triglyceridemia, cholesterolemia, and higher serum IL-1β associated with impaired learning and memory. These obese mice also showed activation of microglia and astrocytes and significant immunoreactivity of neuroinflammatory and apoptosis markers, such as TNF-α, COX-2, and Caspase-3, in addition to lower expression of neurogenesis and synaptic plasticity markers, such as NeuN, KI-67, CREB-p, and BDNF. FOS and GOS treatment significantly improved the biochemistry profile and decreased serum IL-1β levels. Treatment with FOS and GOS also reduced TNF-α, COX-2, Caspase-3, Iba-1, and GFAP-positive cells in the dentate gyrus, decreasing neuroinflammation and neuronal death caused by chronic HFD consumption. In addition, FOS and GOS promoted synaptic plasticity by increasing NeuN, p-CREB, BDNF, and KI-67, restoring spatial learning ability and memory. Moreover, FOS and GOS on HFD modulated the insulin pathway, which was proved by up-regulating IRS/PI3K/AKT signaling pathway, followed by a decreasing Aβ plate and Tau phosphorylation. Furthermore, the prebiotic intervention reshaped the HFD-induced imbalanced gut microbiota by modulating the composition of the bacterial community, markedly increasing Bacteroidetes. In addition, prebiotics decreased intestinal inflammation and leaky gut. In conclusion, FOS and GOS significantly modulated the gut microbiota and IRS/PI3K/AKT signaling pathway, decreased neuroinflammation, and promoted neuroplasticity improving spatial learning and memory. Schematic summarizing of the pathways by FOS and GOS improves memory and learning through the gut-brain axis. FOS and GOS improve the microbial profile, reducing intestinal inflammation and leaky gut in the distal colon. Specifically, the administration of FOS and GOS decreases the expression of TLR4, TNF-α, IL-1β, and MMP9 and increases the expression of occludin and IL-10. Prebiotics inhibit neuroinflammation, neuronal apoptosis, and reactive gliosis in the hippocampus but restore synaptic plasticity, neuronal proliferation, and neurogenesis.

Design of a Biocatalytic Flow Reactor Based on Hierarchically Structured Monolithic Silica for Producing Galactooligosaccharides (GOSs).

Climate change mitigation requires the development of greener chemical processes. In this context, biocatalysis is a pivotal key enabling technology. The advantages of biocatalysis include lower energy consumption levels, reduced hazardous waste production and safer processes. The possibility to carry out biocatalytic reactions under flow conditions provides the additional advantage to retain the biocatalyst and to reduce costly downstream processes. Herein, we report a method to produce galactooligosaccharides (GOSs) from a largely available feedstock (i.e.lactose from dairy production) using a flow reactor based on hierarchically structured monolithic silica. This reactor allows for fast and efficient biotransformation reaction in flow conditions.

In vitro fermentation of Gracilaria lemaneiformis and its sulfated polysaccharides by rabbitfish gut microbes

This study intended to characterize the Gracilaria lemaneiformis (SW)-derived polysaccharide (GLP) and explore the fermentation aspects of SW and GLP by rabbitfish (Siganus canaliculatus) intestinal microbes. The GLP was mainly composed of galactose and anhydrogalactose (at 2.0:0.75 molar ratio) with the linear mainstay of α-(1 → 4) linked 3,6-anhydro-α-l-galactopyranose and β-(1 → 3)-linked galactopyranose units. The in vitro fermentation results showed that the SW and GLP could reinforce the short-chain fatty (SCFAs) production and change the diversity and composition of gut microbiota. Moreover, GLP boosted the Fusobacteria and reduced the Firmicutes abundance, while SW increased the Proteobacteria abundance. Furthermore, the adequacy of feasibly harmful bacteria (such as Vibrio) declined. Interestingly, most metabolic processes were correlated with the GLP and SW groups than the control and galactooligosaccharide (GOS)-treated groups. In addition, the intestinal microbes degrade the GLP with 88.21 % of the molecular weight reduction from 1.36 × 105 g/mol (at 0 h) to 1.6 × 104 g/mol (at 24 h). Therefore, the findings suggest that the SW and GLP have prebiotic potential and could be applied as functional feed additives in aquaculture.

Antioxidant activities and volatile compounds of Chinese cabbage sauce prepared by the combination of Lactobacillus plantarum and functional oligosaccharides

The effects of Lactobacillus plantarum fermentation and addition of fructooligosaccharide (FOS), galactooligosaccharide (GOS) or isomaltooligosaccharide (IMO) on the antioxidant activities and volatile compounds of Chinese cabbage sauces prepared with salt or chilli powder were investigated. Lactobacillus plantarum exhibited excellent growth ability in cabbage sauces and the colony counts remained above 7.70 log CFU/mL throughout the fermentation process. Addition of FOS and GOS significantly promoted Lactobacillus plantarum proliferation remaining above 8.13 log CFU/mL at the end of fermentation. In addition, contents of total phenolic and flavonoid were significantly increased at the end of fermentation, especially for spicy cabbage sauce with oligosaccharides addition. Quercetin content was increased by 88.51% in cabbage sauce after Lactobacillus plantarum fermentation. DPPH radical scavenging activity and FRAP of cabbage sauces were improved by Lactobacillus plantarum fermentation. Contents of gallic acid, caffeic acid, and p-coumaric were positively correlated with antioxidant activities (p < 0.05). Furthermore, a total of 81 volatile compounds were detected in cabbage sauce before and after fermentation, including 22 alcohols, 15 esters, 14 terpenes, 10 ketones, nine hydrocarbons, six aldehydes, three nitriles, and two acids. Total contents of alcohols, esters and ketones were increased by Lactobacillus plantarum fermentation. Terpenes, as new compounds, appeared in fermented cabbage sauce, especially for the fermented spicy cabbage sauces in the range of 1179.98–2428.27 μg/L. Hierarchical cluster analysis indicated that Lactobacillus plantarum fermentation and oligosaccharides addition exhibited positive effects on the formation of volatile substances in Chinese cabbage sauce.

Chickpeas' and Lentils' Soaking and Cooking Wastewaters Repurposed for Growing Lactic Acid Bacteria.

Legumes processing involves large amounts of water to remove anti-nutrients, reduce uncomfortable effects, and improve organoleptic characteristics. This procedure generates waste and high levels of environmental pollution. This work aims to evaluate the galacto-oligosaccharide (GOS) and general carbohydrate composition of legume wastewaters and assess their potential for growing lactic acid bacteria. Legume wastewater extracts were produced by soaking and/or cooking the dry seeds of chickpeas and lentils in distilled water and analysed using high-performance liquid chromatography with refractive index detection. GOS were present in all extracts, which was also confirmed by Fourier transform infrared spectroscopy (FTIR). C-BW extract, produced by cooking chickpeas without soaking, provided the highest extraction yield of 3% (g/100 g dry seeds). Lentil extracts were the richest source of GOS with degree of polymerization ≥ 5 (0.4%). Lactiplantibacillus plantarum CIDCA 83114 was able to grow in de Man, Rogosa, and Sharpe (MRS) broth prepared by replacing the glucose naturally present in the medium with chickpeas' and lentils' extracts. Bacteria were able to consume the mono and disaccharides present in the media with extracts, as demonstrated by HPLC and FTIR. These results provide support for the revalorisation of chickpeas' and lentils' wastewater, being also a sustainable way to purify GOS by removing mono and disaccharides from the mixtures.

Galactooligosaccharide or 2'-Fucosyllactose Modulates Gut Microbiota and Inhibits LPS/TLR4/NF-κB Signaling Pathway to Prevent DSS-Induced Colitis Aggravated by a High-Fructose Diet in Mice.

A high-fructose diet (HFrD) has been reported to exacerbate dextran sulfate sodium (DSS)-induced colitis. 2'-Fucosyllactose (FL) and galactooligosaccharide (GOS) have been shown, respectively, to have preventive and ameliorative effects on colitis, while limited research has explored whether GOS and FL may be equally protective or preventive in mice with HFrD. Here, we evaluated the protective effects of FL and GOS on colitis exacerbated by feeding HFrD and explored the underlying mechanisms. DSS-induced colitis was studied in four randomized C57BL/6J male mice (n = 8 mice/group). Among them, three groups were fed with HFrD, and two received either GOS or FL treatment, respectively. Gut microbial composition was analyzed by 16S rDNA gene sequencing. Intestinal barrier integrity and inflammatory pathway expression were measured using qPCR, immunofluorescence, and Western blot methods. Compared to the HFrD group, GOS or FL treatment increased the α-diversity of the gut microbiota, reduced the relative abundance of Akkermansia, and increased the content of short-chain fatty acids (SCFAs), respectively. Compared with the HFrD group, GOS or FL treatment improved the loss of goblet cells and the reduction of tight junction protein expression, thereby improving intestinal barrier integrity. Also, GOS or FL inhibited the LPS/TLR4/NF-κB signaling pathway and oxidative stress to suppress the inflammatory cascade compared with the HFrD group. These findings suggest that GOS or FL intake can alleviate HFrD-exacerbated colitis, with no significant difference observed between GOS and FL treatments.

Targeted gene manipulation of Leloir pathway genes for the constitutive expression of β-galactosidase and its transgalactosylation product galacto-oligosaccharides from Kluyveromyces lactis GG799 and knockout strains

Galacto-oligosaccharides (GOS) are used as prebiotic ingredients in various food and pharmaceutical industry. At present, production of GOS involves the enzymatic transformation of lactose by transgalactosylation using β-galactosidase. The yeast Kluyveromyces lactis can utilize lactose as its carbon and energy source. In this species lactose is hydrolyzed by an intracellular β-galactosidase (EC 3.2.1.23) which is induced by its substrate and related compounds like galactose. The molecular details of gene regulation in kluyveromyces lactis, we have used multiple knockout approaches to study the constitutive expression by which galactose induces β-galactosidase. The present study involved carrying out to a method of enhancing the constitutive expression of β-galactosidase through galactose induction and its trans-galactosylation reaction for the production of galacto-oligosaccharides (GOS) in Kluyveromyces lactis (K. Lactis) by applying a knockout based approach on Leloir pathway genes based on fusion-overlap extension polymerase chain reaction and transformation into its genome. The k.lactis strain subjected to Leloir pathway genes knockout, resulted in the accumulation of galactose intracellularly and this internal galactose acts as an inducer of galactose regulon for constitutive expression of β-galactosidase at early stationary phase was due to the positive regulatory function of mutant gal1p, gal7p and both. These resulted strains used for trans-galactosylation of lactose by β – galactosidase is characterized for the production of galacto-oligosaccharides. Galactose-induced constitutive expression of β-galactosidase during the early stationary phase of knockout strains was analysed qualitatively & quantitatively. The activity of β-galactosidase of wild type, gal1z, gal7k and gal1z & gal7k strains were 7, 8, 9 and 11 U/ml respectively using high cell density cultivation medium. Based on these expression differences in β-galactosidase, the trans-galactosylation reaction for GOS production and percentage yield of GOS were compared at 25% w/v of lactose. The percentage yield of GOS production of wild type, Δgal1z Lac4+, Δgal7k Lac4++ and Δgal1z Δgal7k Lac4+++mutants strains were 6.3, 13, 17 and 22 U/ml, respectively. Therefore, we propose that the availability of galactose can be used for constitutive over expression of β – galactosidase in Leloir pathway engineering applications and also for GOS production. Further, increased expression of β – galactosidases can be used in dairy industry by-products like whey to produce added value products such as galacto-oligosaccharides.

0201 Prebiotic Diet Impact on Cognitive Performance, Sleepiness, and Mood During Combined Sleep Restriction and Circadian Misalignment

Abstract Introduction The gut microbiome plays a crucial role in health and affects mood and behavior. The composition and function of the gut microbiome can be modified by prebiotics, which are defined as substrates selectively utilized by host microorganisms conferring a health benefit. This study examined the effects of a prebiotic diet combination of polydextrose (PDX) and galacto-oligosaccharides (GOS) on cognitive performance and sleepiness during combined sleep restriction and circadian misalignment. Methods Eleven healthy adults (aged 24.6 ± 4.5, 6 females, 5 males) completed a randomized, double-blind, cross-over study lasting a total of 39 days. Participants consumed 14 days of prebiotic (7.5g/day each of PDX [Danisco] and GOS [FrieslandCampina]) or maltodextrin placebo diets at home(sachets dissolved in water with breakfast) while maintaining ~8h sleep per night at habitual times for two separate weeks before undergoing ~4 days of in laboratory testing under combined sleep restriction (3h sleep opportunity per day) and circadian misalignment (wakefulness at night) conditions. Prebiotic or placebo diet continued in-laboratory. Cognitive function testing occurred every 3h during scheduled wakefulness and included the Psychomotor Vigilance Task (PVT), Stroop Color and Word Test (STROOP) visual analog mood scales (VAS), positive and negative affect scales (PANAS), and the Karolinska sleepiness scale (KSS). Participants had a 3-day washout, then repeated the same procedure with the second condition. Results Sleepiness on the KSS was reduced, and positive mood on the PANAS and calm mood were increased under prebiotic versus placebo (all p &amp;lt; 0.05). Median reaction time on the PVT was faster, whereas median reaction times for congruent stimuli on the STROOP task were slower under the prebiotic diet versus placebo (all p &amp;lt; 0.05). Conclusion A prebiotic diet had beneficial effects on many performance, sleepiness and mood outcomes during combined sleep restriction and circadian misalignment. These findings have important implications for shift workers, emergency responders, and military personnel working under the demanding conditions of sleep restriction and circadian misalignment. Support (if any) Office of Naval Research MURI N00014-15-1-2809, NIH CTSA Grant UL1 TR002535 and Undergraduate Research Opportunities Grant, University of Colorado Boulder.

Microbiota-dependent influence of prebiotics on the resilience of infant gut microbiota to amoxicillin/clavulanate perturbation in an in vitro colon model.

Antibiotic exposure disturbs the developing infant gut microbiota. The capacity of the gut microbiota to recover from this disturbance (resilience) depends on the type of antibiotic. In this study, infant gut microbiota was exposed to a combination of amoxicillin and clavulanate (amoxicillin/clavulanate) in an in vitro colon model (TIM-2) with fecal-derived microbiota from 1-month-old (1-M; a mixed-taxa community type) as well as 3-month-old (3-M; Bifidobacterium dominated community type) breastfed infants. We investigated the effect of two common infant prebiotics, 2'-fucosyllactose (2'-FL) or galacto-oligosaccharides (GOS), on the resilience of infant gut microbiota to amoxicillin/clavulanate-induced changes in microbiota composition and activity. Amoxicillin/clavulanate treatment decreased alpha diversity and induced a temporary shift of microbiota to a community dominated by enterobacteria. Moreover, antibiotic treatment increased succinate and lactate in both 1- and 3-M colon models, while decreasing the production of short-chain (SCFA) and branched-chain fatty acids (BFCA). The prebiotic effect on the microbiota recovery depended on the fermenting capacity of antibiotic-exposed microbiota. In the 1-M colon model, the supplementation of 2'-FL supported the recovery of microbiota and restored the production of propionate and butyrate. In the 3-M colon model, GOS supplementation supported the recovery of microbiota and increased the production of acetate and butyrate.

Comparative study on prebiotic effects of different types of prebiotics in an in vitro fermentation by gut microbiota of shrimp (Litopenaeus vannamei)

Prebiotic fermentation by gut microbiota is a key foundation for prebiotics exhibiting physiological functions. However, the relationship among prebiotic type, gut microbiota and gut microbiota metabolism remains unclear. In this study, the gut microbiota of shrimp (Litopenaeus vannamei) was inoculated into medium containing 1% fructooligosaccharide (FOS), galactooligosaccharide (GOS), mannanoligosaccharide (MOS), inulin, β-glucan, isomaltooligosaccharide (IMO) and xylooligosaccharide (XOS). The pH value, digestive enzyme activity, short-chain fatty acid yield and gut microbiota in the fermentation liquid were evaluated. The results showed that after 12 h of in vitro fermentation, β-glucan exhibited the lowest pH value and highest amylase activity among the other types of prebiotics. β-glucan had a higher ability to produce short-chain fatty acids (SCFA) and inhibit the formation of branched-chain fatty acids (BCFA) than the other types of prebiotics. At the genus level, β-glucan markedly promoted the growth of Bacillus. These findings suggest that β-glucan was the most suitable type of prebiotic and had greater prebiotic effects than the other types of prebiotics on the basis of in vitro fermentation by the gut microbiota of shrimp (Litopenaeus vannamei).

Evaluating the prebiotic effect of oligosaccharides on gut microbiome wellness using in vitro fecal fermentation

We previously proposed the Gut Microbiome Wellness Index (GMWI), a predictor of disease presence based on a gut microbiome taxonomic profile. As an application of this index for food science research, we applied GMWI as a quantitative tool for measuring the prebiotic effect of oligosaccharides. Mainly, in an in vitro anaerobic batch fermentation system, fructooligosaccharides (FOS), galactooligosaccharides (GOS), xylooligosaccharides (XOS), inulin (IN), and 2’-fucosyllactose (2FL), were mixed separately with fecal samples obtained from healthy adult volunteers. To find out how 24 h prebiotic fermentation influenced the GMWI values in their respective microbial communities, changes in species-level relative abundances were analyzed in the five prebiotics groups, as well as in two control groups (no substrate addition at 0 h and for 24 h). The GMWI of fecal microbiomes treated with any of the five prebiotics (IN (0.48 ± 0.06) > FOS (0.47 ± 0.03) > XOS (0.33 ± 0.02) > GOS (0.26 ± 0.02) > 2FL (0.16 ± 0.06)) were positive, which indicates an increase of relative abundances of microbial species previously found to be associated with a healthy, disease-free state. In contrast, the GMWI of samples without substrate addition for 24 h (–0.60 ± 0.05) reflected a non-healthy, disease-harboring microbiome state. Compared to the original prebiotic index (PI) and α-diversity metrics, GMWI provides a more data-driven, evidence-based indexing system for evaluating the prebiotic effect of food components. This study demonstrates how GMWI can be applied as a novel PI in dietary intervention studies, with wider implications for designing personalized diets based on their impact on gut microbiome wellness.