Ammonia Elimination Research Articles

The effect of microbes and dissolved oxygen concentration on inorganic and organic substances elimination in a climate changing environment: The aerobic bioreactor

Microbes and dissolved oxygen (DO) concentration are the drivers in the wastewater treatment plant, aerobic bioreactor for the oxidation and decomposition of inorganic and organic substances. Due to global warming, surface and freshwater temperatures are increasing at an average of 1.08 °C. The rising climate temperatures suppress DO which threatens the availability of oxygen for respiration and survival of microbes, risking poor effluent being discharged into the environment. This study aimed to analyze the effect of microbes and DO concentration simultaneously on the elimination of inorganic and organic substances in a climate-changing environment. The results showed that biomass, COD (-0.578⁎⁎), and ammonia (-0.700⁎⁎) produced a negative relation while DO, ammonia (-0.214⁎⁎), and COD (-0.250⁎⁎) produced a negative relation. Although rising climate temperatures suppress DO, microbes strived under these conditions resulting in an effective aerobic bioreactor. Rising climate temperature (32.5 °C) produced the highest biomass (6.51 g/L), COD (145 mg/L), and ammonia (14.5 mg/L) elimination at the lowest DO (3.81 mg/L) concentration. Whereas normal operating temperature produced the lowest biomass (2.289 g/L), COD (94 mg/L), and ammonia (4.5 mg/L) elimination at the highest DO (4.83 mg/L) concentration. In addition, rising climate temperatures produced the highest COD (72.5 mg/L) and ammonia (7.25 mg/L) elimination rate compared with normal operating temperatures that produced the lowest COD (47 mg/L) and ammonia (2.25 mg/L) elimination rate. Therefore, the rising climate temperatures will not affect the microbes and DO concentration during the elimination of inorganic and organic substances, but rather enhance the performance of the aerobic bioreactor.

The Biocatalytic Potential of Aromatic Ammonia-Lyase from Loktanella atrilutea.

Characterization of the aromatic ammonia-lyase from Loktanella atrilutea (LaAAL) revealed reduced activity towards canonical AAL substrates: l-Phe, l-Tyr, and l-His, contrasted by its pronounced efficiency towards 3,4-dimethoxy-l-phenylalanine. Assessing the optimal conditions, LaAAL exhibited maximal activity at pH 9.5 in the ammonia elimination reaction route, distinct from the typical pH ranges of most PALs and TALs. Within the exploration of the ammonia source for the opposite, synthetically valuable ammonia addition reaction, the stability of LaAAL exhibited a positive correlation with the ammonia concentration, with the highest stability in 4 M ammonium carbamate of unadjusted pH of ~9.5. While the enzyme activity increased with rising temperatures yet, the highest operational stability and highest stationary conversions of LaAAL were observed at 30 °C. The substrate scope analysis highlighted the catalytic adaptability of LaAAL in the hydroamination of diverse cinnamic acids, especially of meta-substituted and di-/multi-substituted analogues, with structural modelling exposing steric clashes between the substrates' ortho-substituents and catalytic site residues. LaAAL showed a predilection for ammonia elimination, while classifying as a tyrosine ammonia-lyase (TAL) among the natural AAL classes. However, its distinctive attributes, such as genomic context, unique substrate specificity and catalytic fingerprint, suggest a potential natural role beyond those of known AAL classes.

Exploring the Impact of Palladium Species’ State on Catalytic Ammonia Elimination over Palladium Catalysts

Exploring the Impact of Palladium Species’ State on Catalytic Ammonia Elimination over Palladium Catalysts

Bioaugmentation in Leachate Treatment: Enhancing Ammonia Nitrogen Elimination in US Landfills

Purpose: This research seeks to assess the quantitative effects of implementing bioaugmentation solutions within existing landfill leachate management systems. The study involves the analysis of different sites to gauge the influence on leachate composition, considering various industry management practices such as lagoons, tanks, sewer discharge, or off-site trucking. The primary objective is to examine changes in microbial communities within the leachate, specifically focusing on their impact on ammonia nitrogen elimination rates. The ultimate goal is to achieve lower levels of ammonia nitrogen before the discharge of leachate to publicly owned treatment works (POTW).Methodology: The research employs a comprehensive methodology that involves the examination of diverse landfill sites utilizing various industry management practices for leachate treatment. The analysis includes assessing leachate composition and the study evaluates effectiveness of bioaugmentation in enhancing ammonia elimination rates, considering different leachate treatment approaches and operating conditions. This involves a systematic comparison of outcomes across sites and management practices.Findings: The findings of this study indicate that bioaugmentation is an effective strategy for accelerating ammonia elimination rates in landfill leachate. The analysis reveals notable improvements in microbial communities, leading to reduced levels of ammonia nitrogen in the leachate prior to its discharge to POTW. The study highlights the versatility of bioaugmentation across different industry management practices, showcasing its potential benefits under varying operating conditions and treatment setups.Unique contributor to theory, policy and practice: Based on the study's outcomes, it is recommended that landfill operators and leachate management practitioners consider implementing bioaugmentation solutions to expedite ammonia elimination rates. The findings suggest that bioaugmentation is a cost-effective and fast-to-deploy solution that requires negligible capital expenditure. This approach has the potential to generate significant savings, especially in the face of a more stringent regulatory environment. The recommendations emphasize the adaptability and efficiency of bioaugmentation across a broad range of operating conditions within existing landfill leachate management infrastructure.

Expression and function of the urea cycle in widely-used hepatic cellular models.

The group of rare metabolic defects termed urea cycle disorders (UCDs) occur within the ammonia elimination pathway and lead to significant neurocognitive sequelae for patients surviving decompensation episodes. Besides orthotopic liver transplantation, curative options are lacking for UCDs, with dietary management being the gold clinical standard. Novel therapeutic approaches are essential for UCDs; however, such effort presupposes preclinical testing in cellular models that effectively capture disease manifestation. Several cellular and animal models exist and aim to recapitulate the broad phenotypic spectrum of UCDs; however, the majority of those lack extensive molecular and biochemical characterization. The development of cellular models is emerging since animal models are extremely time and cost consuming, and subject to ethical considerations, including the 3R principle that endorses animal welfare over unchecked preclinical testing. The aim of this study was to compare the extent of expression and functionality of the urea cycle in two commercial hepatoma-derived cell lines, induced pluripotent stem cell hepatocytes (iPSC-Heps), primary human hepatocytes (PHHs) and human liver cell preparations. Using immunoblotting, immunocytochemistry, and stable isotope tracing of the urea cycle metabolites, we identified that the hepatoma-derived, 2-week differentiated HepaRG cells are urea cycle proficient and behave as cellular alternatives to PHHs. Furthermore, HepaRG cells were superior to iPSC-Heps, which are known to exhibit batch-to-batch variabilities in terms of hepatic maturity and enzyme expression. Finally, HepG2 cells lack the urea cycle enzymes ornithine transcarbamylase and arginase 1, the transporter ORNT1, which limits their suitability as model for the study of UCDs.

Upgrading Epoxy Supports for Enzyme Immobilization by Affinity Function Doping—A Case Study with Phenylalanine Ammonia-Lyase from Petroselinum crispum

This article provides a method to upgrade epoxy-functionalized carriers for covalent enzyme immobilization to selective carriers suitable for covalent immobilization of metal affinity-tagged enzymes without the need of preliminary enzyme purification. Affinity function doping of the epoxy-functionalized surface introduces an advanced possibility to avoid the costly and time-consuming downstream processes required for efficient immobilization on non-selective epoxy carriers. Our approach is based on the partial functionalization of surface epoxides via a proper diamine-derived linker and an ethylenediaminetetraacetic dianhydride-based chelator charged with cobalt ions. The solid macroporous carriers, doped with metal affinity functions, have both coordinative binding ability (rapid anchoring the metal affinity-tagged enzymes to the surface) and subsequent covalent bond-forming ability (preferred binding of the tagged enzyme to the surface after proper washing by the residual epoxide functions), enabling a single operation for the enrichment and immobilization of a recombinant phenylalanine ammonia-lyase from parsley fused to a polyhistidine affinity tag. The immobilized PcPAL was applied in the ammonia elimination of racemic phenylalanine, 4-chlorophenylalanine, and 4-bromophenylalanine to produce the corresponding d-phenylalanines, in addition to the formation of (E)-cinnamates, as well as in ammonia addition reactions to (E)-cinnamates, yielding the corresponding enantiopure l-phenylalanines.

Novel Grafted Hydrogel for Iron and Ammonia Removal from Groundwater: A Synthesis and Computational Chemistry Study.

Current research is moving towards iron and ammonia elimination from groundwater. Here, we are using a poly acrylic-poly acrylamide hydrogel that is grafted with 3-chloroaniline. This copolymer was synthesized by addition polymerization technique. The effects of agitation time, dosage and adsorbent temperature on the removal process sensitivity were investigated. The copolymer was described experientially and theoretically. Isothermal kinetic adsorption models are discussed. This hydrogel could be regenerated efficiently (98.3% removal of iron and 100% removal of ammonia). The density functional theory (DFT) method, using B3LYP/6-311G(d,p), and the LANL2DZ level of the theory were managed to investigate the stationary states of the grafted copolymer and the complexation energy of the hydrogel with the studied cations. DFT has been used to investigate the Natural Bond Orbital (NBO) properties to locate the most negative centers on the hydrogel. The calculated complexation energy showed hydrogel selectivity with regard to the studied cations.

Effects and control mechanisms of ammonia, particulate matters and aerosol bacterial compositions in poultry houses by spray technology

Spray technology is an efficacious method to improve the indoor environments of poultry houses. In this study, two kind intensive enclosed poultry houses are sprayed with different spray additives in order to explore the effects and control mechanisms of spray processes on ammonia, particulate matters and aerosol bacterial compositions and investigate the fecal contributions to aerosol bacteria. The results show that the ammonia elimination rates through spray treatment by tap water (TP treatment), by EM microbial agent (EM treatment) or by glutaraldehyde-decamethonium bromide solution (HX treatment) are 67.0%, 85.4% and 96.9% in brood hen house and 60.7%, 76.0% and 94.8% in laying houses. The reductions of ammonia are mainly due to the decreased pH values caused by the increased Lactobacillus in chicken manure rather than the effects of aerosols after spraying. Spray processes reduce the contents of particulate matters while increase the proportions of PM10 and PM2.5 in TSP. The aerosol bacterial compositions after spraying alter mildly. Humidity is the main physicochemical factor leading to the variations of core bacteria in aerosols. The fecal transmission is the major source of aerosol bacteria in poultry houses and the spray processes merely present a relatively small impact on the fecal contribution to aerosol bacteria. The findings are conductive to optimize the breeding environment, enhance the ability of disease prevention and finally achieve the green and efficient cultivation.

Ammonia versus Water Elimination in the Reaction of Diols with Urea under Metal Oxide Catalysis

Ammonia versus Water Elimination in the Reaction of Diols with Urea under Metal Oxide Catalysis

The use of L-phenylalanine ammonia lyase inhibitors in plant ecophysiological studies

Phenylalanine ammonia lyase (PAL) is a key enzyme controlling the biosynthesis of phenolic compounds in plants. PAL catalyzes ammonia elimination from L-phenylalanine in a reaction that yields cinnamic acid, a precursor of a large group of phenylpropanoid compounds. Phenylpropanoids and their derivatives play an important role in regulating plant resistance mechanisms under environmental stresses. By reducing the level of phenolic compounds, PAL inhibitors can induce changes in plant metabolism. This paper presents the current state of knowledge on the use of PAL inhibitors in plant biology, and draws attention to the possibilities of using PAL inhibitors in agriculture in the context of the witnessed climate changes which increase the frequency and intensity of some disasters such as droughts, floods and storms. By reducing the level of phenolic compounds, PAL inhibitors can induce changes in plant metabolism. This paper presents the current state of knowledge on the use of PAL inhibitors in plant biology, and draws attention to the possibilities of using PAL inhibitors in agriculture in the context of the witnessed climate changes.

Quantitative systems pharmacology Model to characterize valproic acid-induced hyperammonemia and the effect of L-carnitine supplementation

Valproic acid (VPA) is a short-chain fatty acid widely prescribed in the treatment of seizure disorders and epilepsy syndromes, although its therapeutic value may be undermined by its toxicity. VPA serious adverse effects are reported to have a significant and dose-dependent incidence, many associated with VPA-induced hyperammonemia. This effect has been linked with reduced levels of carnitine; an endogenous compound involved in fatty acid's mitochondrial β-oxidation by facilitation of its entrance via the carnitine shuttle. High exposure to VPA can lead to carnitine depletion causing a misbalance between the intra-mitochondrial β-oxidation and the microsomal ω-oxidation, a pathway that produces toxic metabolites such as 4-en-VPA which inhibits ammonia elimination. Moreover, a reduction in carnitine levels might be also related to VPA-induced obesity and lipids disorder. In turn, L-carnitine supplementation (CS) has been recommended and empirically used to reduce VPA's hepatotoxicity. The aim of this work was to develop a Quantitative Systems Pharmacology (QSP) model to characterize VPA-induced hyperammonemia and evaluate the benefits of CS in preventing hyperammonemia under both chronic treatment and after VPA overdosing. The QSP model included a VPA population pharmacokinetics model that allowed the prediction of total and unbound concentrations after single and multiple oral doses considering its saturable binding to plasma proteins. Predictions of time courses for 2-en-VPA, 4-en-DPA, VPA-glucuronide, carnitine, ammonia and urea levels, and for the relative change in fatty acids, Acetyl-CoA, and glutamate reflected the VPA induced changes and the efficacy of the treatment with L-carnitine. The QSP model was implemented to give a rational basis for the L-carnitine dose selection to optimize CS depending on VPA dosage regime and to assess the currently recommended L-carnitine rescue therapy after VPA overdosing. Results show that a L-carnitine dose equal to the double of the VPA dose using the same interdose interval would maintain the ammonia levels at baseline. The QSP model may be expanded in the future to describe other adverse events linked to VPA-induced changes in endogenous compounds.

A systematic approach based on artificial intelligence techniques for simulating the ammonia removal by eighteen deep eutectic solvents

The current research attempts to model the ammonia removal capacity of deep eutectic solvents (DES) employing artificial intelligence (AI) techniques. Four well-known AI classes apply to estimate the ammonia dissolution amount in eighteen DESs. The DES chemistry (type, molar concentration of components, and water dose), equilibrium temperature/pressure, and DES-ammonia absorption enthalpy help AI models estimate the ammonia solubility in DESs. The combination of trial-and-error and statistical analysis determines the best structure of AI models first. Then, several well-established model selection strategies apply to find the highest-accurate AI class. It was found that the adaptive neuro-fuzzy inference system (ANFIS) is more reliable than the other tested AI models. The designed ANFIS model precisely estimates 1356 experimental samples of ammonia removal by DESs with the mean absolute relative deviation percent of 3.51, mean absolute deviation percent of 0.121, root mean squared error of 0.216, and correlation of determination of 0.9980. The selected AI model monitors the influence of DES components, molar dose, equilibrium pressure, and equilibrium pressure on ammonia elimination by these green solvents. Both trend and relevancy investigations approved that the ammonia absorption tendency of DESs intensifies by increasing the equilibrium pressure, absorption enthalpy, the number of moles of hydrogen bond acceptor (HBA), and molecular weight of hydrogen bound donor (HBD). In addition, increasing the equilibrium temperature, water dosage in DES structure, HBA molecular weight, and the number of HBD moles decreases ammonia removal by DESs.

Characterization of Phenylalanine Ammonia Lyases from Lettuce (Lactuca sativa L.) as Robust Biocatalysts for the Production of d- and l-Amino Acids.

Phenylalanine ammonia lyase (PAL) catalyzes the reversible conversion of l-phenylalanine into the corresponding trans-cinnamic acid, providing a route to optically pure α-amino acids. We explored the catalytic function of all five PALs encoded in the genome of lettuce (Lactuca sativa L.) that are previously known to be involved in wound browning. All LsPALs were active toward l-phenylalanine in the ammonia elimination reaction and displayed maximum activity at 55-60 °C and pH 9.0-9.5. However, four of them, LsPAL1-LsPAL4, showed significantly higher activity and thermal stability than LsPAL5, as well as a broader substrate spectrum including some challenging substrates with steric demanding or electron-donating substituents. The best one LsPAL3 was subjected to the kinetic resolution of a panel of 21 rac-phenylalanine derivatives, as well as the ammonia addition of 21 cinnamic acid derivatives. It showed excellent enantioselectivity in most cases and significantly better activity than previously described PALs for a number of challenging non-natural substrates, demonstrating its great potential in biocatalysis.

Rare Adult-onset Citrullinemia Type 1 in the Postpartum Period: A Case Report.

Citrullinemia type 1 (CTLN1) is a urea cycle disorder caused by defective argininosuccinate synthetase leading to impaired ammonia elimination. Urea cycle disorders are typically diagnosed on neonatal screening but rarely can lie dormant until a metabolic stressor causes initial onset of symptoms in adulthood. A 23-year-old female presented four days postpartum to the emergency department (ED) obtunded and declined to the point of requiring intubation. Labs revealed hyperammonemia, and she was subsequently found to have CTLN1. Urea cycle disorders presenting in adulthood are a rare etiology for the common ED complaint of altered mental status. The low incidence makes these treatable disorders easy to overlook leading to potentially significant morbidity and mortality. Therefore, it is important to recognize the risk factors that can trigger an acute metabolic derangement. This case highlights common risk factors for metabolic stress, possible presenting symptoms, and the positive outcome achievable when recognized and treated in a timely fashion.

Characterization of two novel ammonia transporters, HIAT1α and HIAT1β, in the American Horseshoe Crab, Limulus polyphemus

The American horseshoe crab, Limulus polyphemus, excretes nitrogenous waste in the form of toxic ammonia across their book gills. The mechanism of this branchial excretion is yet unknown. In the current study, two isoforms of a novel ammonia transporter, LpHIAT1α and LpHIAT1β, have been identified in L. polyphemus. Both isoforms have 12 predicted transmembrane regions and share 82.7% of amino acid identity to each other, and 77–86% amino acid homology to HIAT1 found in fish and crustaceans. In L. polyphemus, both isoforms were expressed in the gills, coxal glands, and brain. Slightly higher mRNA expression levels of LpHIAT1α were observed in the peripheral mitochondria-poor region of the gill (PMPA), central mitochondria-rich region of the gill (CMRA), and brain compared to the LpHIAT1β isoform. A functional expression analysis of LpHIAT1α and LpHIAT1β in Xenopus laevis oocytes resulted in a significantly lower uptake of the radiolabeled ammonia analogue 3H-methylamine when compared to controls, indicating an ammonia excretory function of the proteins. Exposure to elevated environmental ammonia (HEA, 1 mmol l−1 NH4Cl) caused an increase in mRNA expression of LpHIAT1β in the ion-conductive ventral gill half. High mRNA expression of both isoforms in the brain, and the observation that LpHIAT1α and LpHIAT1β likely mediate cellular ammonia excretion, suggests that these highly conserved ammonia transporters have an important housekeeping function in cellular ammonia elimination.

Pearls & Oy-sters: Status Epilepticus and Cerebral Edema From Hyperammonemia Due to Disseminated Ureaplasma and Mycoplasma Species.

Nonhepatic hyperammonemia syndrome is a rare cause of neurologic dysfunction and cerebral edema and has most commonly been reported in posttransplant patients. Only recently has opportunistic infection with Ureaplasma species and Mycoplasma hominis been found to be key to the pathogenesis. We describe the cases of 3 immunosuppressed patients who developed hyperammonemia syndrome with new-onset refractory status epilepticus and diffuse cerebral edema. PCR was positive for M hominis in 1 patient and Ureaplasma parvum in the other 2. Despite early diagnostic suspicion and aggressive management with empirical antibiotics, seizure control, hypertonic saline, and ammonia elimination, none of our patients survived this life-threatening infection. Nonhepatic hyperammonemia and new-onset seizures can be presenting features of disseminated Ureaplasma species and M hominis infections in posttransplant patients. Immunosuppression in the absence of organ transplantation is likely sufficient to trigger this entity, as was the case in our third patient. When suspected, empiric combination antibiotics should be used due to high likelihood of resistance. The diagnostic test of choice is PCR. Patients with hyperammonemia syndrome associated with these infections typically have a poor prognosis. Early recognition and aggressive multimodal interventions may be key to ameliorating the high mortality and severe neurologic sequelae from this entity.

Hypokalaemia - an active contributor to hepatic encephalopathy?

Patients with cirrhosis are prone to electrolyte disorders, including hypokalaemia. The available evidence suggests that hypokalaemia facilitates hyperammonaemia and thus increases the risk for hepatic encephalopathy (HE). In case studies, plasma potassium decrements were followed by plasma ammonia increments and HE progression, which was reversed by potassium supplementation. The explanation to the hyperammonaemia may be that hypokalaemia both stimulates renal ammonia production and reduces hepatic ammonia elimination by urea synthesis. Further, hypokalaemia eases the entrance of the increased ammonia into the central nervous system because the lower potassium ion concentration favours the competition of NH4+ ions for potassium transporters across the blood brain barrier, and because hypokalaemia-induced metabolic alkalosis increases the amount of gaseous ammonia, which freely passes the barrier. Potassium depletion thus seems to be a mechanistic contributor to HE, supporting the clinical notion of routinely correcting low potassium in patients with cirrhosis.

Genetic Analysis and Fine Mapping of ZmGHT1 Conferring Glufosinate Herbicide Tolerance in Maize (Zea mays L.).

Weed interference in the crop field is one of the major biotic stresses causing dramatic crop yield losses, and the development of herbicide-resistant crops is critical for weed control in the application of herbicide technologies. To identify herbicide-resistant germplasms, we screened 854 maize inbreed lines and 25,620 seedlings by spraying them with 1 g/L glufosinate. One plant (L336R), possibly derived from a natural variation of line L336, was identified to have the potential for glufosinate tolerance. Genetic analysis validated that the glufosinate tolerance of L336R is conferred by a single locus, which was tentatively designated as ZmGHT1. By constructing a bi-parental population derived from L336R, and a glufosinate sensitive line L312, ZmGHT1 was mapped between molecular markers M9 and M10. Interestingly, genomic comparation between the two sequenced reference genomes showed that large scale structural variations (SVs) occurred within the mapped region, resulting in 2.16 Mb in the inbreed line B73, and 11.5 kb in CML277, respectively. During the fine mapping process, we did not detect any additional recombinant, even by using more than 9500 F2 and F3 plants, suspecting that SVs should also have occurred between L336R and L312 in this region, which inhibited recombination. By evaluating the expression of the genes within the mapped interval and using functional annotation, we predict that the gene Zm00001eb361930, encoding an aminotransferase, is the most likely causative gene. After glufosinate treatment, lower levels of ammonia content and a higher activity of glutamine synthetase (GS) in L336R were detected compared with those of L336 and L312, suggesting that the target gene may participate in ammonia elimination involving GS activity. Collectively, our study can provide a material resource for maize herbicide resistant breeding, with the potential to reveal a new mechanism for herbicide resistance.

Thermally Induced Solid-Phase Quasi-Intramolecular Redox Reactions of [Hexakis(urea-O)iron(III)] Permanganate: An Easy Reaction Route to Prepare Potential (Fe,Mn)Ox Catalysts for CO2 Hydrogenation.

Research on new reaction routes and precursors to prepare catalysts for CO2 hydrogenation has enormous importance. Here, we report on the preparation of the permanganate salt of the urea-coordinated iron(III), [hexakis(urea-O)iron(III)]permanganate ([Fe(urea-O)6](MnO4)3) via an affordable synthesis route and preliminarily demonstrate the catalytic activity of its (Fe,Mn)Ox thermal decomposition products in CO2 hydrogenation. [Fe(urea-O)6](MnO4)3 contains O-coordinated urea ligands in octahedral propeller-like arrangement around the Fe3+ cation. There are extended hydrogen bond interactions between the permanganate ions and the hydrogen atoms of the urea ligands. These hydrogen bonds serve as reaction centers and have unique roles in the solid-phase quasi-intramolecular redox reaction of the urea ligand and the permanganate anion below the temperature of ligand loss of the complex cation. The decomposition mechanism of the urea ligand (ammonia elimination with the formation of isocyanuric acid and biuret) has been clarified. In an inert atmosphere, the final thermal decomposition product was manganese-containing wuestite, (Fe,Mn)O, at 800 °C, whereas in ambient air, two types of bixbyite (Fe,Mn)2O3 as well as jacobsite (Fe,Mn)T-4(Fe,Mn)OC-62O4), with overall Fe to Mn stoichiometry of 1:3, were formed. These final products were obtained regardless of the different atmospheres applied during thermal treatments up to 350 °C. Disordered bixbyite formed first with inhomogeneous Fe and Mn distribution and double-size supercell and then transformed gradually into common bixbyite with regular structure (and with 1:3 Fe to Mn ratio) upon increasing the temperature and heating time. The (Fe,Mn)Ox intermediates formed under various conditions showed catalytic effect in the CO2 hydrogenation reaction with <57.6% CO2 conversions and <39.3% hydrocarbon yields. As a mild solid-phase oxidant, hexakis(urea-O)iron(III) permanganate, was found to be selective in the transformation of (un)substituted benzylic alcohols into benzaldehydes and benzonitriles.

A seed-like hydrogel with metabolic cascade microbiota for oral treatment of liver failure

Liver failure is a fatal disease with a mortality rate of 80%. The only access to treat liver failure is invasive operation, which is restricted by limited donor sources or high costs. Thus, non-invasive medication for liver failure is urgently needed. Herein, we tried the first attempt to design a seed-inspired hydrogel with a micro-ecosystem, which imitates characteristics of seed with high intestinal adaptability, for the elimination of harmful metabolites in liver failure using a cascade reaction triggered by encapsulated microbes. Focusing on abnormal ammonia assimilation and intestinal oxygen metabolism, a two-component artificial microbiota was constructed to enable efficient intestinal oxygen consumption and subsequent hypoxia-induced ammonia elimination. More importantly, we imitated plant seeds with high adaptability to the intestinal environment to improve the performance of bacteria. A hydrogel particle with the seed shape, lignin coating, and porous structure, for achieving intentional retention, bacterial protection, and diffusion promotion, respectively was prepared. In murine and porcine models of liver failure, the artificial reactor lowered the blood ammonia to prevent nerve damage, and consumed oxygen to inhibit pathogenic facultative anaerobes for alleviating liver failure. This work underscores the great potential of medication with a bioinspired micro-ecosystem for liver failure.