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Biotechnology For Biofuels and... Jun 2024Hybrid thermochemical-biological processes have the potential to enhance the carbon and energy recovery from organic waste. This work aimed to assess the carbon and...
Hybrid thermochemical-biological processes have the potential to enhance the carbon and energy recovery from organic waste. This work aimed to assess the carbon and energy recovery potential of multifunctional processes to simultaneously sequestrate syngas and detoxify pyrolysis aqueous condensate (PAC) for short-chain carboxylates production. To evaluate relevant process parameters for mixed culture co-fermentation of syngas and PAC, two identical reactors were run under mesophilic (37 °C) and thermophilic (55 °C) conditions at increasing PAC loading rates. Both the mesophilic and the thermophilic process recovered at least 50% of the energy in syngas and PAC into short-chain carboxylates. During the mesophilic syngas and PAC co-fermentation, methanogenesis was completely inhibited while acetate, ethanol and butyrate were the primary metabolites. Over 90% of the amplicon sequencing variants based on 16S rRNA were assigned to Clostridium sensu stricto 12. During the thermophilic process, on the other hand, Symbiobacteriales, Syntrophaceticus, Thermoanaerobacterium, Methanothermobacter and Methanosarcina likely played crucial roles in aromatics degradation and methanogenesis, respectively, while Moorella thermoacetica and Methanothermobacter marburgensis were the predominant carboxydotrophs in the thermophilic process. High biomass concentrations were necessary to maintain stable process operations at high PAC loads. In a second-stage reactor, Aspergillus oryzae converted acetate, propionate and butyrate from the first stage into L-malate, confirming the successful detoxification of PAC below inhibitory levels. The highest L-malate yield was 0.26 ± 2.2 mol/mol recorded for effluent from the mesophilic process at a PAC load of 4% v/v. The results highlight the potential of multifunctional reactors where anaerobic mixed cultures perform simultaneously diverse process roles, such as carbon fixation, wastewater detoxification and carboxylates intermediate production. The recovered energy in the form of intermediate carboxylates allows for their use as substrates in subsequent fermentative stages.
PubMed: 38907325
DOI: 10.1186/s13068-024-02532-2 -
Microbiome Jun 2024
PubMed: 38907261
DOI: 10.1186/s40168-024-01846-5 -
Frontiers in Cellular and Infection... 2024The gut microbiota plays a vital role in the development of sepsis and in protecting against pneumonia. Previous studies have demonstrated the existence of the gut-lung...
BACKGROUND
The gut microbiota plays a vital role in the development of sepsis and in protecting against pneumonia. Previous studies have demonstrated the existence of the gut-lung axis and the interaction between the gut and the lung, which is related to the prognosis of critically ill patients; however, most of these studies focused on chronic lung diseases and influenza virus infections. The purpose of this study was to investigate the effect of faecal microbiota transplantation (FMT) on -related pulmonary infection via the gut-lung axis and to compare the effects of FMT with those of traditional antibiotics to identify new therapeutic strategies.
METHODS
We divided the mice into six groups: the blank control (PBS), pneumonia-derived sepsis (KP), pneumonia-derived sepsis + antibiotic (KP + PIP), pneumonia-derived sepsis + faecal microbiota transplantation(KP + FMT), antibiotic treatment control (KP+PIP+PBS), and pneumonia-derived sepsis+ antibiotic + faecal microbiota transplantation (KP + PIP + FMT) groups to compare the survival of mice, lung injury, inflammation response, airway barrier function and the intestinal flora, metabolites and drug resistance genes in each group.
RESULTS
Alterations in specific intestinal flora can occur in the gut of patients with pneumonia-derived sepsis caused by . Compared with those in the faecal microbiota transplantation group, the antibiotic treatment group had lower levels of proinflammatory factors and higher levels of anti-inflammatory factors but less amelioration of lung pathology and improvement of airway epithelial barrier function. Additionally, the increase in opportunistic pathogens and drug resistance-related genes in the gut of mice was accompanied by decreased production of favourable fatty acids such as acetic acid, propionic acid, butyric acid, decanoic acid, and secondary bile acids such as chenodeoxycholic acid 3-sulfate, isodeoxycholic acid, taurodeoxycholic acid, and 3-dehydrocholic acid; the levels of these metabolites were restored by faecal microbiota transplantation. Faecal microbiota transplantation after antibiotic treatment can gradually ameliorate gut microbiota disorder caused by antibiotic treatment and reduce the number of drug resistance genes induced by antibiotics.
CONCLUSION
In contrast to direct antibiotic treatment, faecal microbiota transplantation improves the prognosis of mice with pneumonia-derived sepsis caused by by improving the structure of the intestinal flora and increasing the level of beneficial metabolites, fatty acids and secondary bile acids, thereby reducing systemic inflammation, repairing the barrier function of alveolar epithelial cells, and alleviating pathological damage to the lungs. The combination of antibiotics with faecal microbiota transplantation significantly alleviates intestinal microbiota disorder, reduces the selection for drug resistance genes caused by antibiotics, and mitigates lung lesions; these effects are superior to those following antibiotic monotherapy.
Topics: Animals; Gastrointestinal Microbiome; Klebsiella Infections; Klebsiella pneumoniae; Mice; Fecal Microbiota Transplantation; Anti-Bacterial Agents; Lung; Sepsis; Prognosis; Disease Models, Animal; Humans; Male; Mice, Inbred C57BL
PubMed: 38903943
DOI: 10.3389/fcimb.2024.1392376 -
Frontiers in Microbiology 2024The aim of this study was to investigate the effects of () and propionic acid (PA) on fermentation characteristics and microbial community of amaranth () silage with...
Utilisation of and propionic acid to improve silage quality of amaranth before and after wilting: fermentation quality, microbial communities, and their metabolic pathway.
OBJECTIVE
The aim of this study was to investigate the effects of () and propionic acid (PA) on fermentation characteristics and microbial community of amaranth () silage with different moisture contents.
METHODS
Amaranth was harvested at maturity stage and prepared for ensiling. There were two moisture content gradients (80%: AhG, 70%: AhS; fresh material: FM) and three treatments (control: CK, : LP, propionic acid: PA) set up, and silages were opened after 60 d of ensiling.
RESULTS
The results showed that the addition of and PA increased lactic acid (LA) content and decreased pH of amaranth after fermentation. In particular, the addition of PA significantly increased crude protein content ( < 0.05). LA content was higher in wilted silage than in high-moisture silage, and it was higher with the addition of and PA ( < 0.05). The dominant species of AhGLP, AhSCK, AhSLP and AhSPA were mainly , and . The dominant species in AhGCK include , and was dominated in AhGPA, which affected fermentation quality. and PA acted synergistically after ensiling to accelerate the succession of dominant species from gram-negative to gram-positive bacteria, forming a symbiotic microbial network centred on lactic acid bacteria. Both wilting and additive silage preparation methods increased the degree of dominance of global and overview maps and carbohydrate metabolism, and decreased the degree of dominance of amino acid metabolism categories.
CONCLUSION
In conclusion, the addition of to silage can effectively improve the fermentation characteristics of amaranth, increase the diversity of bacterial communities, and regulate the microbial community and its functional metabolic pathways to achieve the desired fermentation effect.
PubMed: 38903783
DOI: 10.3389/fmicb.2024.1415290 -
Nutrition & Diabetes Jun 2024Dietary-resistant starch is emerging as a potential therapeutic tool to limit the negative effects of diabetes on the kidneys. However, its metabolic and...
BACKGROUND
Dietary-resistant starch is emerging as a potential therapeutic tool to limit the negative effects of diabetes on the kidneys. However, its metabolic and immunomodulatory effects have not yet been fully elucidated.
METHODS
Six-week-old db/db mice were fed a diet containing 12.5% resistant starch or a control diet matched for equivalent regular starch for 10 weeks. db/m mice receiving the control diet were utilised as non-diabetic controls. Freshly collected kidneys were digested for flow cytometry analysis of immune cell populations. Kidney injury was determined by measuring albuminuria, histology, and immunohistochemistry. Portal vein plasma was collected for targeted analysis of microbially-derived metabolites. Intestinal histology and tight junction protein expression were assessed.
RESULTS
Resistant starch limited the development of albuminuria in db/db mice. Diabetic db/db mice displayed a decline in portal vein plasma levels of acetate, propionate, and butyrate, which was increased with resistant starch supplementation. Diabetic db/db mice receiving resistant starch had a microbially-derived metabolite profile similar to that of non-diabetic db/m mice. The intestinal permeability markers lipopolysaccharide and lipopolysaccharide binding protein were increased in db/db mice consuming the control diet, which was not seen in db/db mice receiving resistant starch supplementation. Diabetes was associated with an increase in the kidney neutrophil population, neutrophil activation, number of C5aR1+ neutrophils, and urinary complement C5a excretion, all of which were reduced with resistant starch. These pro-inflammatory changes appear independent of fibrotic changes in the kidney.
CONCLUSIONS
Resistant starch supplementation in diabetes promotes beneficial circulating microbially-derived metabolites and improves intestinal permeability, accompanied by a modulation in the inflammatory profile of the kidney including neutrophil infiltration, complement activation, and albuminuria. These findings indicate that resistant starch can regulate immune and inflammatory responses in the kidney and support the therapeutic potential of resistant starch supplementation in diabetes on kidney health.
Topics: Animals; Mice; Kidney; Albuminuria; Male; Neutrophil Infiltration; Diabetic Nephropathies; Resistant Starch; Gastrointestinal Microbiome; Starch; Diabetes Mellitus, Experimental; Mice, Inbred C57BL
PubMed: 38902253
DOI: 10.1038/s41387-024-00305-2 -
Brain Communications 2024Neurodegeneration in the autoimmune disease multiple sclerosis still poses a major therapeutic challenge. Effective drugs that target the inflammation can only partially...
Neurodegeneration in the autoimmune disease multiple sclerosis still poses a major therapeutic challenge. Effective drugs that target the inflammation can only partially reduce accumulation of neurological deficits and conversion to progressive disease forms. Diet and the associated gut microbiome are currently being discussed as crucial environmental risk factors that determine disease onset and subsequent progression. In people with multiple sclerosis, supplementation of the short-chain fatty acid propionic acid, as a microbial metabolite derived from the fermentation of a high-fiber diet, has previously been shown to regulate inflammation accompanied by neuroprotective properties. We set out to determine whether the neuroprotective impact of propionic acid is a direct mode of action of short-chain fatty acids on CNS neurons. We analysed neurite recovery in the presence of the short-chain fatty acid propionic acid and butyric acid in a reverse-translational model of human-induced primary neurons differentiated from people with multiple sclerosis-derived induced pluripotent stem cells. We found that recovery of damaged neurites is induced by propionic acid and butyric acid. We could also show that administration of butyric acid is able to enhance propionic acid-associated neurite recovery. Whole-cell proteome analysis of induced primary neurons following recovery in the presence of propionic acid revealed abundant changes of protein groups that are associated with the chromatin assembly, translational, and metabolic processes. We further present evidence that these alterations in the chromatin assembly were associated with inhibition of histone deacetylase class I/II following both propionic acid and butyric acid treatment, mediated by free fatty acid receptor signalling. While neurite recovery in the presence of propionic acid is promoted by activation of the anti-oxidative response, administration of butyric acid increases neuronal ATP synthesis in people with multiple sclerosis-specific induced primary neurons.
PubMed: 38894951
DOI: 10.1093/braincomms/fcae182 -
Nutrients Jun 2024Propionate defects (PDs) mainly include methylmalonic (MMA) and propionic acidemia (PA) defects. Lifelong PD patients progress from the compensated to the decompensated...
Propionate defects (PDs) mainly include methylmalonic (MMA) and propionic acidemia (PA) defects. Lifelong PD patients progress from the compensated to the decompensated stages, the latter of which are characterized by life-threatening acidemia and hyperammonemia crises. PD patients can suffer immunocompromise, especially during the decompensation stage. There is a significant gap in the research regarding the humoral immune response in PD patients. Here, we analyzed serum immunoglobulin concentrations and hemograms across compensated and decompensated stages in PD patients. Nutritional status and crisis triggers of decompensation were also explored. Twenty patients were studied, and 25 decompensation events (DE) and 8 compensation events (CE) were recorded. Compared with those in the CE group, the IgG levels in the DE group (513.4 ± 244.5 mg/dL) were significantly lower than those in the CE group (860.8 ± 456.5 mg/dL) ( < 0.0087). The mean hemoglobin concentration was significantly lower in the DE group (11.8 g/dL) than in the CE group (13.4 g/dL) ( < 0.05). The most frequent (48%) possible decompensation trigger factor was infection. Most of the events were registered in eutrophic patients (87.9%), despite which 65.2% and 50% of patients who experienced decompensated and compensated events, respectively, presented with hypogammaglobulinemia G. These findings provide evidence of the immunodeficiency of PD patients, independent of their nutritional status. We suggest that PD patients be managed as immunocompromised independently of their nutritional status or metabolic state (compensated or decompensated).
Topics: Humans; Nutritional Status; Male; Female; Agammaglobulinemia; Middle Aged; Aged; Immunoglobulin G; Adult; Propionates; Propionic Acidemia
PubMed: 38892708
DOI: 10.3390/nu16111775 -
Nutrients May 2024Short-chain fatty acids (SCFAs) have been reported to be associated with the pathogenesis of irritable bowel syndrome (IBS), but the results are conflicting. (Meta-Analysis)
Meta-Analysis Review
CONTEXT
Short-chain fatty acids (SCFAs) have been reported to be associated with the pathogenesis of irritable bowel syndrome (IBS), but the results are conflicting.
OBJECTIVE
Here, a systematic review of case-control studies detecting fecal SCFAs in IBS patients compared with healthy controls (HCs) and self-controlled studies or randomized controlled trials (RCTs) investigating fecal SCFA alterations after interventions were identified from several databases.
DATA SOURCES
A systematic search of databases (PubMed, Web of Science, and Embase) identified 21 studies published before 24 February 2023. Data extractions: Three independent reviewers completed the relevant data extraction.
DATA ANALYSIS
It was found that the fecal propionate concentration in IBS patients was significantly higher than that in HCs, while the acetate proportion was significantly lower. Low-FODMAP diets significantly reduced the fecal propionate concentration in the IBS patients while fecal microbiota transplantation and probiotic administration did not significantly change the fecal propionate concentration or acetate proportion.
CONCLUSIONS
The results suggested that the fecal propionate concentration and acetate proportion could be used as biomarkers for IBS diagnosis. A low-FODMAP diet intervention could potentially serve as a treatment for IBS while FMT and probiotic administration need more robust trials.
Topics: Irritable Bowel Syndrome; Humans; Feces; Fatty Acids, Volatile; Fecal Microbiota Transplantation; Probiotics; Propionates; Randomized Controlled Trials as Topic; Acetates; Female; Gastrointestinal Microbiome; Biomarkers; Male; Adult; Case-Control Studies
PubMed: 38892659
DOI: 10.3390/nu16111727 -
Nutrients May 2024This study investigated the effect of astragalus polysaccharide (APS, an ingredient with hypoglycemic function in a traditional Chinese herbal medicine) on gut...
This study investigated the effect of astragalus polysaccharide (APS, an ingredient with hypoglycemic function in a traditional Chinese herbal medicine) on gut microbiota and metabolites of type 2 diabetes mellitus (T2DM) patients using a simulated fermentation model in vitro. The main components of APS were isolated, purified, and structure characterized. APS fermentation was found to increase the abundance of and and decrease the level in the fecal microbiota of T2DM patients. Apart from increasing propionic acid, APS also caused an increase in all-trans-retinoic acid and thiamine (both have antioxidant properties), with their enrichment in the KEGG pathway associated with thiamine metabolism, etc. Notably, APS could also enhance fecal antioxidant properties. Correlation analysis confirmed a significant positive correlation of Lactobacillus with thiamine and DPPH-clearance rate, suggesting the antioxidant activity of APS was related to its ability to enrich some specific bacteria and upregulate their metabolites.
Topics: Gastrointestinal Microbiome; Humans; Diabetes Mellitus, Type 2; Fermentation; Polysaccharides; Astragalus Plant; Feces; Antioxidants; Male; Female; Middle Aged; Thiamine; Bifidobacterium; Lactobacillus; Hypoglycemic Agents
PubMed: 38892631
DOI: 10.3390/nu16111698 -
Nutrients May 2024Serum-derived bovine immunoglobulin (SBI) prevents translocation and inflammation via direct binding of microbial components. Recently, SBI also displayed potential...
Serum-derived bovine immunoglobulin (SBI) prevents translocation and inflammation via direct binding of microbial components. Recently, SBI also displayed potential benefits through gut microbiome modulation. To confirm and expand upon these preliminary findings, SBI digestion and colonic fermentation were investigated using the clinically predictive ex vivo SIFR technology (for 24 human adults) that was, for the first time, combined with host cells (epithelial/immune (Caco-2/THP-1) cells). SBI (human equivalent dose (HED) = 2 and 5 g/day) and the reference prebiotic inulin (IN; HED = 2 g/day) significantly promoted gut barrier integrity and did so more profoundly than a dietary protein (DP), especially upon LPS-induced inflammation. SBI also specifically lowered inflammatory markers (TNF-α and CXCL10). SBI and IN both enhanced SCFA (acetate/propionate/butyrate) via specific gut microbes, while SBI specifically stimulated valerate/bCFA and indole-3-propionic acid (health-promoting tryptophan metabolite). Finally, owing to the high-powered cohort (n = 24), treatment effects could be stratified based on initial microbiota composition: IN exclusively stimulated (acetate/non-gas producing) for subjects classifying as /-enterotype donors, coinciding with high acetate/low gas production and thus likely better tolerability of IN. Altogether, this study strongly suggests gut microbiome modulation as a mechanism by which SBI promotes health. Moreover, the SIFR technology was shown to be a powerful tool to stratify treatment responses and support future personalized nutrition approaches.
Topics: Humans; Gastrointestinal Microbiome; Cattle; Adult; Animals; Male; Inflammation; Female; Caco-2 Cells; Immunoglobulins; Colon; Inulin; THP-1 Cells; Fermentation; Middle Aged; Prebiotics; Intestinal Mucosa; Fatty Acids, Volatile
PubMed: 38892520
DOI: 10.3390/nu16111585