Microbial Fermentation Research Articles

Production of neohesperidin from hesperetin by an engineered strain of Escherichia coli

Neohesperidin is a flavonoid glycoside widely used in the food and pharmaceutical industries. The current production of neohesperidin mainly relies on extraction from plants. Microbial fermentation demonstrates a promising prospect as an environmentally friendly, efficient, and economical method. In this study, we designed and constructed the biosynthetic pathway of neohesperidin in an Escherichia coli strain by introducing the glycosyltransferase UGT73B2 from Arabidopsis thaliana, rhamnose synthase VvRHM-NRS from Vitis vinifera, and rhamnose transferase Cm1,2RhaT from Citrus maxima. After optimization of the module and the uridine diphosphate (UDP)-glucose synthetic pathway, the engineered strain produced 4.64 g/L neohesperidin in a 5 L bioreactor, and the molar conversion rate of hesperetin was 45.8%. This has been the highest titer reported to date for the biosynthesis of neohesperidin in microorganisms. This study lays a foundation for the construction and application of strains with high yields of neohesperidin and provides a potential choice for the microbial production of other flavonoid glycosides.

The structural properties of “Huilou” yam starch fermented with five microbial species

In this study, we employed two lactic acid bacterial species, two yeast species, and Bacillus amyloliquefaciens to ferment “Huilou” yam starch. The aim was to explore the effects of fermentation time and microbial species on the structural properties of yam starch. The results showed that fermentation caused an increase in relative crystallinity (29.23 %–37.98 %) compared with native starch (25.69 %). The fermentation process altered the thermal properties of yam starch, leading to higher enthalpy of gelatinization values compared with unfermented starch. Notably, an absorption peak of native starch shifted from 992 cm−1 to 1015 cm−1 upon 2-day fermentation by Bacillus amyloliquefaciens and 5-day fermentation by Lactobacillus plantarum or Pediococcus pentococcus, associated with an increase in the presence of amorphous structures in yam starch. “Huilou” yam starch obtained through lactic acid bacterial fermentation exhibited a significant presence of organic acids, whereas samples derived from Bacillus amyloliquefaciens fermentation were primarily affected by amylase activity. Following yeast fermentation, organic acids and amylase were observed, albeit with relatively low influence. This research reveals that microbial fermentation can potentially alter the structural characteristics of yam starch, which can improve the quality of yam starch-based foods.

Circular Bioeconomy in Action: Transforming Food Wastes into Renewable Food Resources.

The growing challenge of food waste management presents a critical opportunity for advancing the circular bioeconomy, aiming to transform waste into valuable resources. This paper explores innovative strategies for converting food wastes into renewable food resources, emphasizing the integration of sustainable technologies and zero-waste principles. The main objective is to demonstrate how these approaches can contribute to a more sustainable food system by reducing environmental impacts and enhancing resource efficiency. Novel contributions of this study include the development of bioproducts from various food waste streams, highlighting the potential of underutilized resources like bread and jackfruit waste. Through case studies and experimental findings, the paper illustrates the successful application of green techniques, such as microbial fermentation and bioprocessing, in valorizing food wastes. The implications of this research extend to policy frameworks, encouraging the adoption of circular bioeconomy models that not only address waste management challenges but also foster economic growth and sustainability. These findings underscore the potential for food waste to serve as a cornerstone in the transition to a circular, regenerative economy.

Bacterial co-fermentation mediated synthesis of chitosan from Procambarus clarkii enhances disease resistance in rice

The increasing dietary demand for red swamp crayfish (Procambarus clarkii) in China has resulted in a significant rise in the quantity of its by-products, which are currently underutilized or discarded. Chitosan, a widely used plant immune inducer, is one of the major components found in red swamp crayfish shells (RSCS). However, the utilization of chitosan derived from RSCS in agriculture is hindered by the lack of an efficient microbial fermentation-based production system. To address this issue, this study aims to establish a chitosan fermentation procedure by using RSCS as substrate. The efficiency by using Bacillus followed with Acetobacter for a continuous co-fermentation tested. Bacillus NJ-B2 or NJ-B3 with Acetobacter NJ-A1 demonstrated the highest co-fermentation efficacy, achieving 95 % deproteinization and 90 % demineralization of RSCS, respectively. The extracted chitosan was characterized by fourier transform infrared and scanning electron microscopy. Notably, the application of this RSCS-derived chitosan significantly improves rice resistance against Xanthomonas oryzae pv. oryzae, Magnaporthe oryzae, and Ustilaginoidea virens. These findings collectively indicate that this established method can effectively produce chitosan from RSCS via microbial fermentation, providing an environmentally friendly way for plant protection.

Efficacy of zinc nanoparticle supplementation on ruminal environment in lambs

BackgroundZinc nanoparticles (NPs) are characterized by high bioavailability, small size, and high absorbability. The purpose of this experiment was to determine the effect of Zn-NP feed supplementation on ruminal fermentation, microbiota, and histopathology in lambs. In vitro (24 h), short-term (STE, 28 d), and long-term (LTE, 70 d) experiments were performed. The lambs in STE were fed a basal diet (BD) composed of 350 g/d ground barley and 700 g/d meadow hay (Control), BD enriched with ZnO-NPs (80 mg Zn/kg of diet, ZnO-NPs), and BD enriched with Zn phosphate-based NPs (80 mg Zn/kg of diet, ZnP-NP). The in vitro gas production technique was used in incubated rumen fluid from STE. The lambs in LTE were fed BD (Control), BD enriched with ZnO-NPs (40 mg Zn/kg of diet, ZnO-NP40), BD enriched with ZnO-NPs (80 mg Zn/kg of diet, ZnO-NP80) and BD enriched with ZnO (80 mg Zn/kg of diet, ZnO-80).ResultsAfter 24 h of incubation, dry matter digestibility was higher for ZnO-NP and ZnP-NP substrates than the control in an in vitro experiment (P < 0.001). The total bacterial population in the STE was lower (P < 0.001) in the ZnP-NP group than in the control and ZnO-NP groups, but the protozoan populations were not significantly different. The ammonia-N concentration in LTE was lowest in the ZnO-NP80 group (P = 0.002), but the activities of carboxymethyl cellulase (P < 0.001) and xylanase (P = 0.002) were higher in the ZnO-NP40, ZnO-NP80, and ZnO-80 groups than in the control group. Morphological observation after STE and LTE revealed histological changes (e.g. inflammation of the epithelium or edema of the connective tissue) in the rumen of lambs.ConclusionZn-NP supplementation up to 70 d improved feed-use efficiency and influenced ammonia-N concentration and activities of hydrolases in the rumen. The active ruminal fermentation affected the health of the ruminal papillae and epithelium in the lambs, regardless of the application's form, dose, or duration. However, by affecting rumen microbial fermentation, Zn-NPs could alter fermentation patterns, thereby increasing the capacity of host rumen epithelial cells to transport short-chain fatty acids.

Microbial Fermentation and Therapeutic Potential of p-Cymene: Insights into Biosynthesis and Antimicrobial Bioactivity

p-Cymene (p-C) [1-methyl-4-(1-methylethyl)-benzene] is a monoterpene found in a variety of plants and has several biological activities, including antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. This paper explores the microbial fermentation pathways involved in the biosynthesis of p-C, with an emphasis on its potential as a therapeutic agent. Through microbial and biochemical processes, p-C can be produced using renewable precursors such as limonene and 1,8-cineole. Recent advances in fermentation technology have enhanced the efficiency of p-C production, highlighting its role in various industries. Additionally, this paper reviews the antimicrobial bioactivity of p-C, focusing on its ability to inhibit pathogens and modulate immune responses. The integration of microbial biosynthesis and fermentation methods offers a sustainable approach to producing p-C for applications in the perfume, cosmetics, food, and pharmaceutical sectors. Understanding these biosynthetic pathways is crucial for advancing the use of p-C as a bio-based chemical with therapeutic potential. In particular, p-C inhibits the expression of cytokine signal 3 in intestinal inflammation and modulates antioxidant and immunomodulatory systems to protect barrier cells and maintain the mucus layer.

Synergistic role of carbon quantum dots on biohydrogen production

Biohybrid system has their distinct ability to improve microbial fermentation. This study demonstrates the role of surface-doped carbon quantum dots (CQDs) on dark fermentative biohydrogen production using lactobacillus organic-hybrid biocatalyst. Herein, nitrogen-doped carbon quantum dots (N-CQDs) with < 5 nm (having a surface charge of +2.6 mV) and un-doped carbon quantum dots (CQDs) (having a surface charge of −4.5 mV) were synthesized via chemical assisted process. Subsequently, the biohybrid systems were constructed via augmentation of N-CQDs and CQDs with Lactobacillus delbreuckii and assessed for biohydrogen production. The results revealed that both the biohybrid systems (N-CQDs- Lactobacillus delbreuckii and CQDs- Lactobacillus delbreuckii) provided improved hydrogen production than that of the native bacterial strain. Interestingly, the obtained N-CQDs- Lactobacillus delbreuckii system provided the maximum hydrogen yield of 2.01 mol/mol hexose, followed by 1.86 mol/mol hexose from CQDs- Lactobacillus delbreuckii, which is about 33 % and 19 % higher than the bare bacterial strain. The electron transfer and metabolic alteration of microbes by carbon quantum dots were assessed using cyclic voltammetry (CV) and VFA production. It was concluded that the improved bio-hydrogen production from N-CQDs- Lactobacillus delbreuckii is attributed to enhanced electron transfer, which regulates the central metabolic pathway of acetate and butyrate synthesis with the least production of lactate and other reduced end product formation.

Conversion of glycerol into value-added products

Biomass residues and industrial waste are of great interest for their potential to produce a wide range of bioenergy and value-added products. Crude glycerol can be valorized into value added products by several microorganisms through microbial fermentation. Thus, Significant efforts have been made to develop biological methods to convert crude glycerol into various valuable chemicals and fuels, including 1, 3-propanediol, hydrogen and ethanol.In this context, our work have use glycerol medium as source of carbon for investigate bioethanol and 1, 3-propandiol production, using a microbial consortium. All experiments was carried out in sealed bottles, the reaction medium is placed in the shaker incubator at 37°C with stirring at 130 rpm. . Nitrogen gas was injected to create anaerobic conditions. The highest concentration of ethanol and 1,3 – propanediol obtained were 3.47 (g/l) and 4.8 mg/l respectively . These results highlight promising avenues for the valorization of biomass residues and industrial wastes in sustainable bioenergy production.

Bioconversion of sugar beet molasses into functional exopolysaccharides by beet juice-derived lactic acid bacteria

Sugar beet molasses, a sugar-rich byproduct of sugar beet industry, have great potential as a biorefinery feedstock for the production of value-added bio-products by microbial fermentation. The production of functional exopolysaccharides (EPS) by lactic acid bacteria (LAB) represents a promising strategy for valorizing sugar processing waste. This study screened and identified high-efficiency EPS-producing LAB isolates from beet juice. Among the 32 isolates, six LAB strains including Limosilactobacillus fermentum YL7, Lactiplantibacillus plantarum YL4, TC10, and CJ10, Leuconostoc mesenteroides TCT3 and TCT4, exhibited efficient bio-conversion of beet molasses to LAB-EPS, with yields varying from 13.96 to 22.26 g/L. Antioxidant activity analysis revealed that EPS from these strains displayed significant scavenging activities against ABTS+, DPPH, and -OH radicals. Notably, EPS produced by L. plantarum TC10 and L. fermentum YL7 exhibited superior ABTS + scavenging capacity, with rates up to 99.48% and 95.89% at 4 mg/mL, respectively. Additionally, EPS from strains YL4, YL7, TCT3 and TCT4 showed significant antibiofilm activity against S. aureus and E. coli, with EPS-YL7 inhibiting S. aureus biofilm formation by up to 90.49% at 8.0 mg/mL. Furthermore, EPS from strains TCT4 demonstrated great tolerance to digestive fluid compared to EPS from other strains, with a retention rate of 72% at the end of intestinal digestion. These findings suggest that EPS-producing LAB strains from beet juice can efficiently convert beet molasses into valuable EPS utilized as functional food ingredients.

APPLICATION OF OHMIC HEATING IN THE FOOD INDUSTRY, IMPACT ON FOOD COMPONENTS AND "HURDLE APPROACH"

The application of thermal processes in the food industry causes a decrease in the quality of the final product, such as nutritional value and organoleptic characteristics. Many alternative methods offer uniform and rapid heating and provide the desired microbial lethality without reducing overall product quality. Ohmic heating is an emerging technique for food processing that has been used in recent decades as an alternative to conventional heating. It is a rapid heating method with big potential in the food industry. More particularly, ohmic heating of food is used for microbial inactivation, blanching, fermentation, gelatinization, peeling, evaporation, drying, extraction, pasteurization, and sterilization. This review summarizes the application of ohmic heating to different types of food products, the impact on food components, as well as the synergistic effect of ohmic heating with other non-thermal preservation techniques as well as the case of its combination with packed food items. The optimization of the ohmic heating approach reduces the duration of the process, achieves microbial and enzyme stability, increases the yield, and preserves the organoleptic and bioactive components in food commodities. Applying ohmic heating in combination with other non-thermal food preservation techniques such as UV-C radiation, pulsed electric field, high pressure, ultrasound, vacuum and the addition of preservatives contributes to reducing the intensity of the applied electric field, the temperature, and the treatment. In addition, it contributes to the extension of the shelf life as well as preserving the nutritional and organoleptic quality of food.

Effect of inoculum sources on caproic acid production from food waste through lactate-based chain elongation: Properties and microbial succession

Caproic acid (CA) production is a promising way to valorize food waste (FW), but the low CA yield seriously restricts its application. Inoculum source as a key factor can affect the microbial communities and CA fermentation processes, but was not fully explored. In the present study, three common inoculum sources namely anaerobic digestion sludge (AD), pit mud (PM) and raw FW (RFW) were selected as inocula to initiate CA production from FW. The organics conversion properties, microbial community succession processes and bacterial metabolism pathways were investigated. Results showed that carbohydrates were effectively degraded into lactic acid and then to CA based on lactate-based chain elongation. The CA yield (0.37 g-COD/g-VS) using AD was higher than that inoculated with PM (0.26 g-COD/g-VS) and RFW (0.32 g-COD/g-VS). Although microbial communities in inocula were totally different, they exhibited similar succession with Firmicutes and Bacteroidetes as the dominant functional phyla. Logically, lactic acid-producing bacteria (e.g. Lactobacillus, Limosilactobacillus and Sporolactobacillus) were enriched at the early stage to prepare electron donor (lactate), and then were replaced by chain elongation bacteria for CA production. However, unclassified_Ruminococcaceae was dominant in reactor with AD, unclassified_Ruminococcaceae, Bifidobacterium, Clostridium_sensu_stricto and unclassified_Prevotellaceae were largely detected in reactors inoculated with PM and RFW, which resulted in different CA yield. This study provides useful information for caproate production from FW, and widens the knowledge of cleaner production from wastes.

Effects of Phaffia rhodozyma on microbial community dynamics and tobacco quality during tobacco fermentation.

Carotenoids are important precursors of various aroma components in tobacco and play an important role in the sensory quality of tobacco. Phaffia rhodozyma is a species of Xanthophyllomyces capable of synthesizing a highly valuable carotenoid-astaxanthin, but has not yet been used in improving tobacco quality. The dynamic changes of microbial community and metabolites during tobacco fermentation were analyzed in combination with microbiome and metabolome, and the quality of tobacco after fermentation was evaluated by sensory scores. P. rhodozyma could grow and produce carotenoids in tobacco extract, with a maximum biomass of 6.50 g/L and a maximum carotenoid production of 36.13 mg/L at 100 g/L tobacco extract. Meanwhile, the correlation analysis combined with microbiome and metabolomics showed that P. rhodozyma was significantly positively correlated with 11 metabolites such as 6-hydroxyluteolin and quercetin. Furthermore, the contents of alcohols, ketones and esters, which were important aromatic components in fermented tobacco, reached 77.57 μg/g, 58.28 μg/g and 73.51 μg/g, increasing 37.39%, 265.39% and 266.27% compared to the control group, respectively. Therefore, the aroma and flavor, and taste scores of fermented tobacco increased by 0.5 and 1.0 points respectively. This study confirmed that P. rhodozyma fermentation could effectively improve the sensory evaluation of tobacco, and provided a novel microbial fermentation method to improve tobacco quality.

Hemp Seed Protein Hydrolysate Enriched with γ-Aminobutyric Acid and Peptides by Microbial Bioconversion

Hemp seed protein (HSP), a by-product of hemp oil processing, was converted into a functional protein ingredient enriched with γ-aminobutyric acid (GABA) and peptides through a two-step microbial fermentation process. To enhance peptide and free amino acid production from HSP, it was hydrolyzed using alkaline protease produced by Bacillus subtilis HA. The HSP was hydrolyzed at a degree of 40% at 55 °C for 24 h, yielding a pH of 6.55, an acidity of 1.22%, and 205.45 mg% tyrosine equivalents. This process resulted in the production of low molecular-weight peptides. (&lt;5000 Da) The total amino acid content and branched-chain amino acids (leucine, isoleucine, and valine) were 6.78 mg/g and 1.47 mg/g. Subsequently, the production of γ-aminobutyric acid (GABA) in the HSP hydrolysate was optimized through co-fermentation with lactic acid bacteria in the presence of 5% MSG at 30 °C for 5 days. The serial co-fermented HSP hydrolysate exhibited a GABA content of 33.98 mg/g and a viable bacterial count of 9.51 log CFU/mL for Lb. plantarum KS2020. This serial co-fermentation process, combining proteolysis and lactic acid fermentation, not only increased the peptide content but also promoted GABA accumulation, positioning HSP hydrolysate as a promising candidate for functional foods with potential health benefits.

Assessment of safety: In vitro reverse mutation and in vivo acute oral toxicity tests of three biomass products from amino acid-producing Corynebacterium glutamicum

Microbial fermentation has emerged as a pivotal process for sustainable production of essential goods and chemicals. Corynebacterium glutamicum is a proficient platform organism that contributes significantly to amino acid production through microbial fermentation. Despite its recognized safety, challenges persist in efficiently biosynthesizing natural products compared with other organisms. This study evaluated the safety of biomass products from bioengineered C. glutamicum through two different toxicological studies: a bacterial reverse mutation test (AMES test) and an acute oral toxicity test in rats. Three types of dried fermentation biomass products, each engineered for the enhanced production of specific amino acids (L-lysine, L-threonine, and L-tryptophan), were examined. The tests were conducted in compliance with Organization for Economic Co-operation and Development guidelines and revealed no mutagenicity or acute toxicity at the tested doses. These findings suggest the safety of biomass products from bioengineered C. glutamicum as potential feed materials, although further toxicity studies are recommended for comprehensive evaluation. This study underscores the importance of stringent safety assessments for advancing biotechnological applications and provides valuable insights into the potential utilization of microbial fermentation products in various industries. Moreover, this study highlights the significance of regulatory compliance and adherence to international standards to ensure the safety and efficacy of novel biotechnological products.

Genetic optimization of the human gut bacterium Phocaeicola vulgatus for enhanced succinate production

The demand for sustainably produced bulk chemicals is constantly rising. Succinate serves as a fundamental component in various food, chemical, and pharmaceutical products. Succinate can be produced from sustainable raw materials using microbial fermentation and enzyme-based technologies. Bacteroides and Phocaeicola species, widely distributed and prevalent gut commensals, possess enzyme sets for the metabolization of complex plant polysaccharides and synthesize succinate as a fermentative end product. This study employed novel molecular techniques to enhance succinate yields in the natural succinate producer Phocaeicola vulgatus by directing the metabolic carbon flow toward succinate formation. The deletion of the gene encoding the methylmalonyl-CoA mutase (Δmcm, bvu_0309-0310) resulted in a 95% increase in succinate production, as metabolization to propionate was effectively blocked. Furthermore, deletion of genes encoding the lactate dehydrogenase (Δldh, bvu_2499) and the pyruvate:formate lyase (Δpfl, bvu_2880) eliminated the formation of fermentative end products lactate and formate. By overproducing the transketolase (TKT, BVU_2318) in the triple deletion mutant, succinate production increased from 3.9 mmol/g dry weight in the wild type to 10.9 mmol/g dry weight. Overall, succinate yield increased by 180% in the new mutant strain P. vulgatus Δmcm Δldh Δpfl pG106_tkt relative to the parent strain. This approach is a proof of concept, verifying the genetic accessibility of P. vulgatus, and forms the basis for targeted genetic optimization. The increase of efficiency highlights the huge potential of P. vulgatus as a succinate producer with applications in sustainable bioproduction processes.Key points• Deleting methylmalonyl-CoA mutase gene in P. vulgatus doubled succinate production• Triple deletion mutant with transketolase overexpression increased succinate yield by 180%• P. vulgatus shows high potential for sustainable bulk chemical production via genetic optimization

Third-Generation L-Lactic Acid Biorefinery Approaches: Exploring the Viability of Macroalgae Detritus

AbstractRising concerns over fossil fuel depletion and plastic pollution have driven research into biodegradable alternatives, such as polylactic acid (PLA). Microbial fermentation is preferred for lactic acid production due to its ability to yield enantiomerically pure lactic acid, which is essential for PLA synthesis, unlike the racemic mixture from chemical synthesis. However, commercial lactic acid production using first-generation feedstocks faces challenges related to cost and sustainability. Macroalgae offer a promising alternative with their rapid growth rates and carbon capture capabilities. This review explores recent technological advancements in macroalgae physicochemical characterization, optimization of fermentation conditions, and innovative pretreatment methods to enhance sugar conversion rates for L-LA production. It also covers downstream processes for L-LA recovery, presenting a complete macroalgal biorefinery system. Environmental impacts and economic prospects are assessed through exergy and techno-economic analyses. By valorizing macroalgae detritus, this study underscores its potential to support a sustainable biorefinery industry, addressing economic feasibility and environmental impact.

Environmental pH and compound structure affect the activity of short-chain carboxylic acids against planktonic growth, biofilm formation, and eradication of the food pathogen Salmonella enterica.

Short-chain carboxylic acids (SCCAs) that are naturally produced by microbial fermentation play an essential role in delaying microbial spoilage. SCCAs are structurally diverse, but only a few of them are routinely used in food biopreservation. This study investigated the effects of environmental pH and intrinsic properties of 21 structurally different SCCAs on the antimicrobial and antibiofilm activity against Salmonella enterica. Inhibition of SCCA toward planktonic and biofilm growth of S. enterica was higher in an acidic environment (pH 4.5) that is common in fermented products, and for SCCA that possessed both a high acid dissociation strength (pKa) (>4.0) and a positive hydrophobicity [octanol/water partition coefficient (log Kow)]. Crotonic and caproic acids were identified as SCCAs with potential as biopreservatives even at near-neutral pH. SCCA with hydrophilic groups such as lactic acid did not inhibit S. enterica at concentrations up to 50 mM, while SCCA with benzene or methyl groups or a double bond prevented S. enterica growth and biofilm formation. Stimulation of biofilm formation was observed for formic, acetic, and propionic acid close to the minimum inhibitory concentration to reduce 50% of cell density (MIC50) of planktonic cells, and for citric and isocitric acid with an MIC50 of ≥50 mM. The presence of low concentrations of formic and propionic acids during biofilm formation conferred protection during eradication possibly due to a pre-adaptation effect, yet two consecutive acid treatments were successful in eradicating biofilms if the first acid treatment was two- to threefold of the MIC50.IMPORTANCEThis study provides a systematic comparison on the antimicrobial and antibiofilm activity of more than 20 structurally different SCCAs against a common food pathogen. We tested the antimicrobial activity at controlled pH and identified the structure-dependent antimicrobial effects of SCCA without the confounding influence of acidification. The combined effect of pKa and log Kow was identified as an important feature that should be considered when deciding for a specific SCCA in the application as antimicrobial. Our results imply that additional phenomena such as the use of SCCA as substrate and cellular pre-adaption effects have to be taken into consideration. We finally present a two-step treatment as an efficient approach to eradicate biofilms, which can be applied for the disinfection of contact surfaces and manufacturing equipment. Results obtained here can serve as guidelines for application of SCCA to avoid the growth of food pathogens and/or to develop biopreserved food systems.

239 Growth performance and gut health indicators of Escherichia coli-challenged weaned pigs fed diets supplemented with Bacillus subtilis or Enterococcus faecium

Abstract A study evaluated the effects of adding B. subtilis or E. faecium based probiotics in diets for weaned pigs challenged with E. coli on growth performance and indicators of gut health. Pigs [n = 64; initial body weight (BW) = 6.95 kg] weaned at 22 d of age were obtained in 2 batches of 32 pigs each. The pigs were from sows that were homozygous susceptible to infection by F4 strain of E. coli. Pigs in each batch were housed in 16 pens in 2 rooms: first room with 4 pens and second room with 12 pens. Pigs were fed 3 diets for 14 d. The diets were control or control plus B. subtilis (1×10E6 CFU/kg) or E. faecium (1×10E6 CFU/kg). On d 7 and 8 of the experiment, all pigs in the second room were orally challenged with F4 strain of E. coli (5 mL with ~109 CFUּ mL-1ּ d-1) to create the following 4 treatments with 4 pensּ traetment-1ּ batch-1) (8 pens/treatment for the study): unchallenged pigs fed control diet, challenged pigs fed control diet, challenged pigs fed control diet plus E. faecium, and challenged pigs fed control diet plus B. subtilis. Challenging pigs with E. coli F4 reduced (P &amp;lt; 0.05) average daily gain (ADG) for d 7 to 11 and d 11 to 14 of the study from 81 to -67 g and 460 to 259 g, respectively; increased (P &amp;lt; 0.05) plasma haptoglobin concentration (PHC) on d 9 from 1.10 to 1.69 mg/mL and fecal E. coli F4 content (FEC) on d 11 from 4.92 to 7.86 log copies/g; and decreased (P &amp;lt; 0.05) volatile fatty acids (VFA) concentration in the cecum and colon on d 14 from 89.5 to 52.3 mmol/kg and 88.1 to 63.9 mmol/kg, respectively. The E. faecium supplementation did not affect ADG for d 0 to 7 of the study but increased (P &amp;lt; 0.05) ADG for d 7 to 11 by 161%. The E. faecium supplementation did not affect FEC, PHC, and VFA concentration in the cecum and colon. The B. subtilis supplementation did not affect ADG and ADFI, FEC, PHC, but tended to increase (P &amp;lt; 0.10) VFA concentration in the cecum and colon by 32 and 20%, respectively. In conclusion, challenging weaned pigs with the E. coli F4 reduced growth performance and microbial fermentation in the hindgut and increased fecal E. coli shedding. Supplemental E. faecium probiotic improved ADG of weaned pigs after their challenge with E. coli, implying that it can be included in diets for weaned pigs raised under commercial conditions to improve their performance. The B. subtilis probiotic can be included in diets for weaned pigs to counteract the reducing impact of E. coli infection on microbial fermentation in the hindgut.

UHPLC-Q-TOF-MS/MS identification of metabolites in cereal beverage ‘Borde’ and its anti-obesity efficacy in Caenorhabditis elegans model

This research explores the remarkable impact of fermented cereals such as sorghum, maize, and wheat with Pediococcus acidilactici WS07, a strain isolated from Ethiopia's traditional borde beverage. The fermented cereal extracts were thoroughly evaluated for antioxidant activity, inhibition of pancreatic lipase and α-glucosidase, metabolite identification through UHPLC-Q-TOF-MS/MS, and in vivo efficacy using the C. elegans model. The results revealed significant enhancements in the bioactive compounds of fermented cereals, demonstrating promising directions for obesity prevention strategies. Notably, the fermented sorghum extracts improved lipase (88.23 %) and α-glucosidase (85.62 %) inhibitory activities compared to its unfermented counterparts. The antioxidant properties of all fermented samples were confirmed through improved DPPH (67.77–71.86 %) and ABTS (59.91–65.49 %) scavenging activities. Fermentation also led to a notable increase in polyphenols and flavonoids, with detailed metabolite analysis revealing a dynamic shift in the composition of these bioactive compounds. Additionally, C. elegans indicates that fermented extracts extend lifespan, reduce lipid accumulation, and lower triglycerides, highlighting their potential as functional foods for health enhancement and obesity management. This study not only underscores the efficacy of P. acidilactici WS07 fermentation in transforming cereals into nutrient-rich functional foods but also provides insight into how microbial fermentation can unlock the health-promoting potential of traditional diets.

147 The ‘horse-side’ of host-microbe interactions and gastrointestinal homeostasis in the equine hindgut

Abstract Homeostasis is a complex physiological process that enables biological systems to maintain balanced internal environments in response to internal and external stimuli. In the equine gastrointestinal (GI) tract, homeostasis involves a network of factors that regulate gene expression, maintain the integrity of the mucosal barrier, and modulate immune responses to pathogenic microorganisms while supporting commensal bacteria that provide benefits to the host (Figure 1). These factors work together and respond to changes in diet, environment, external stress, and challenges by infectious agents or toxins. Proper gastrointestinal function is dependent on maintaining homeostasis in the system, and the dynamic interactions between the microbial population (the microbiota) and the equine host are central to this equilibrium. The regulation and interplay between the equine host and GI microbiota are evident in the distribution of distinct microbial communities within the various compartments of the equine hindgut. The contributions of each compartment to digestive physiology and the overlap with various stages of microbial fermentation in the equine hindgut are well-researched. What remains to be documented is gene expression in tissues of the equine GI and the underlying role this might play in the processes of digestion, physiology, and homeostasis in the GI. To better understand the roles that host gene expression plays in the interactions with the microbiota, it is critical that we investigate gene expression in the different tissues along the intestinal tract. Protein-coding genes are crucial in maintaining the health of the gastrointestinal tract. They direct the synthesis of various structural elements, molecular transporters, and digestive enzymes, which support digestion, nutrient absorption, and gut integrity. Non-coding genes also play an important role in regulating protein-coding gene expression, modulating immune responses, and maintaining gut barrier function. Moreover, there is evidence that non-coding transcripts regulate the composition of microbial communities in the GI tract. The presentation will focus on the current research and future directions for investigating protein-coding and non-coding gene expression to understand the mechanisms involved in the host-microbe interaction in the equine hindgut and their potential role in maintaining GI homeostasis.