Glyoxylate Research Articles

Enterobacter cloacae: a villain in CaOx stone disease?

To explore the roles microbiome of urinary tract played in calcium oxalate stones (CaOx) formation, we collected two sides’ pelvis urine of patients with unilateral CaOx stones to set self-control to diminish the influence of systemic factors. Patients with unilateral CaOx stones were recruited in our study according to strict criteria. 16S rRNA gene sequencing was applied to every pair of pelvis urine. Bacterial genome sequencing of Enterobacter cloacae was conducted and bioinformatic analysis was applied to explore the possible pathways of Enterobacter cloacae inducing CaOx stones formation. In vivo experiments were conducted to validate our claims. Von Kossa staining, TUNEL assay and Western Blot were applied to SD rats exploring the mechanism of stone formation. We found 26 significantly different bacteria between stone sides and non-stone sides’ pelvis urine, among which Enterobacter cloacae ranked the most different. Bacterial genome sequencing of Enterobacter cloacae revealed that its virulence factors included Flagellin, LPS and Fimbrial. GO and KEGG analysis revealed it probably induced CaOx stone formation via ion binging and signaling transduction pathways. The results of animal experiments indicated that Glyoxylic Acid could promote apoptosis and crystal depositions of kidney comparing with control group while pre-injected with Enterobacter cloacae could apparently compound the effects. While Western Blot demonstrated that Glyoxylic Acid or Enterobacter cloacae could increase the expression of IL-6, Mcp-1, BMP2 and OPN in rats’ kidney, Glyoxylic Acid and Enterobacter cloacae together could aggravate these increases. These findings indicated that Enterobacter cloacae might play important roles in CaOx stones formation. However, this study is just a preliminary exploration; further studies still need to be conducted.

Structure, conformations, vibrations and quantum chemical investigations of 2–(1H–indol–3–yl)–2–oxoacetic acid

Detailed structural, electronic and vibrational properties of 2–(1H–indol–3–yl)–2–oxoacetic acid or 3–indoleglyoxylic acid (3IGA) have been analysed with the help of FT–IR, FT–Raman and FT–NMR spectra along with the support of the theoretical investigations by B3LYP method. The conformational investigations on 3IGA showed that s–trans–I conformer with intramolecular hydrogen bonding is the most stable one. The range of total electron density of the molecule 3IGA is found to be +7.383e × 10–2 to – 7.383e × 10–2 and the electrostatic potential of 3AI is in the range +1.167e × 10–2 to –1.167e × 10–2. The energy gap ΔE = (ELUMO–EHOMO) of 3IGA is 4.1008 eV. The n(O20) → π*(C18–O19) is strongly stabilized by 54.01 kcal mol–1. Significant lowering and broadening of the stretching O–H band indicates the presence of intramolecular O–H···O hydrogen bonding. The chemical shift of C2 (138.00 ppm) and C3 (112.57 ppm) is much higher in 3IGA when compared to indole 125.07 and 100.84 ppm, respectively. The atoms C3, C4, C7, C6 and N1 are favourable for the nucleophilic attack while C16, C18, C2, C9, C5 and C8 are favourable for electrophilic attack.

Surface engineered environment-stable red-emitting fluorides for white light emitting diodes

Poor water stability is the main problem of commercialized Mn 4+ -doped fluorides for white light emitting diode (WLED) application. This work proposes a surface engineering strategy to rebuild a Mn 4+ -free fluoride shell on fluorides to effectively resist the destruction from water molecules. By simple processing using glyoxylic acid (GA) solution, the moisture resistance of the red-emitting fluorides can be significantly improved. The photoluminescence (PL) quantum efficiency (QE) of the surface-engineered K 2 SiF 6 :Mn 4+ (KSFM-GA) still maintain 98.43% after water immersion for 360 h, in sharp contrary to the untreated one (its PLQE decreases to 59.79%). Additionally, PL intensity of the hydrolyzed KSFM can be recovered to 99.1% through the treatment of the reducing GA solution. By using the high-stability KSFM-GA red phosphor, the as-fabricated high-performance warm-WLED device can still maintain 84.6% in luminous efficacy, higher than that (79.6%) with the untreated KSFM, after 500 h of aging in a high temperature (85 °C) and high humidity (85%) environment. • The surface engineering strategy is very simple for processing the commercial fluorides. • The surface reconstructed fluorides well remain the morphology and photoluminescence (PL) properties. • The PL intensity of the surface-engineered fluorides is almost unchanged even after being immersed in water for 360 h. • The reducing glyoxylic acid solution can fully restore the photoluminescence intensity of the hydrated fluorides. • The white-LED device with the surface-engineered fluoride shows improved color stability.

Capillary electrophoresis applied for the determination of acidity constants and limiting electrophoretic mobilities of ionizable herbicides including glyphosate and its metabolites and for their simultaneous separation.

Thermodynamic acidity constants and limiting ionic mobilities were determined for polyprotic non-chromophore analytes using capillary electrophoresis with capacitively coupled contactless conductivity detection. It was not necessary to work with buffers of identical ionic strength as ionic strength effects on effective electrophoretic mobilities were corrected by modeling during data evaluation (software AnglerFish). The mobility data from capillary electrophoresis coupled to conductivity detection were determined in the pH range from 1.25 to 12.02 with a high resolution (36pH steps). With this strategy, thermodynamic acidity constants and limiting ionic mobilities for various acidic herbicides were determined, sometimes for the first time. The model analytes included glyphosate, its metabolites, and its acetylated derivates (aminomethyl phosphonic acid, glyoxylic acid, sarcosine, glycine, N-acetyl glyphosate, N-acetyl aminomethyl phosphonic acid, hydroxymethyl phosphonic acid). The obtained data were used in simulations to optimize separations by capillary electrophoresis. Simulations correlated very well to experimental results. With the new method, the separation of glyphosate from interfering components like phosphate in beer samples was possible.

Facilitated series electrochemical hydrogenation of oxalic acid to glycolic acid using TiO2 nanotubes

In this study, the electrochemical reduction of oxalic acid (OX) was performed at electrodes made of TiO2 nanotubes (TNTs) in an aqueous medium under potentiostatic control in a two-compartment cell. The competing H2 evolution was almost non-existent at an applied potential of −1.0 V vs Ag/AgCl. Thus, complete conversion of OX was achieved in high chemical (95%) and Faradaic (67%) yields. The selectivity of glycolic acid (GC) formation over that of glyoxylic acid (GO) is controlled by the length of the TNTs. A high selectivity (GC/GO ≈ 10) was obtained (glycolic acid/glyoxylic acid ≈ 10). The physical properties of the TNTs, such as length, uniformity, and mechanical strength, were controlled by varying the anodization time and the electrolyte composition.

A new method for C(sp2)-H sulfonylmethylation with glyoxylic acid and sodium sulfinates.

We herein describe a C4 sulfonylmethylation of pyrazol-5-amines with glyoxylic acid and sodium sulfinates. The reaction only needed water as a solvent, and it featured mild reaction conditions, simple operation, and high regioselectivity. Various C4 sulfonylmethylated pyrazol-5-amines were obtained in good to excellent yields. Moreover, this sulfonylmethylation method was applicable for C(sp2)-H sulfonylmethylation of other substrates such as enamines, indoles, and antipyrines by adding a catalyst and changing the solvent. Biological evaluation revealed that some products had antiproliferative activity against cancer cell lines.

Application of the Cu@PET Composite Track-Etched Membranes for Catalytic Removal of Cr(VI) Ions

This research examines the features of obtaining composite track-etched membranes based on copper microtubes using various compositions of a deposition solution and various types of reducing agents, such as formaldehyde (Cu_CHOH@PET), dimethylamine borane (Cu_DMAB@PET), glyoxylic acid (Cu_Gly@PET). The structure and composition of the membrane composites were studied by scanning elec-tron microscopy and X-ray phase analysis. It was shown that in the case of using dimethylamine borane as a reducing agent, the obtained composites consisted of copper(I) oxide (37.4 %) and copper(0) (62.6 %), in other cases single-component copper microtubes were obtained. The reduction reaction of chromium(VI) ions was used to evaluate the catalytic ability of prepared composites. It was found that the removal efficiency of chromium ions reached up to 95–97 % in the case of single-component composites; the presence of a cop-per(I) oxide phase in the structure of the Cu_DMAB@PET composites significantly reduced the activity of catalysts and under similar conditions, only 41% of the contaminant was removed from the reaction system. The degradation reaction of Cr(VI) was found to follow the Langmuir-Hinshelwood mechanism and a pseu-do-first-order kinetic model. The calculated value of the reaction rate constant ka for composites of the Cu_DMAB@PET composition (0.017 min–1) was more than 9 times less than that of composites obtained us-ing glyoxylic acid (0.156 min–1) and more than 15 times less than the ka value of Cu_CHOH@PET samples (0.249 min–1). Effect of temperatures on the catalytic ability of composites was studied in the temperature range of 10–38 °C. Some thermodynamic characteristics such as activation energy, enthalpy, and entropy of activation were calculated. It was found that the minimum value of the activation energy was obtained for the Cu_CHOH@PET samples.

Effects of chitosan on chloroplast protein of vegetable soybean under NaCl stress

Chitosan (CTS) can effectively enhance the tolerance of plants to salt stress, but its role in driving the responses of vegetable soybean seedlings to salt stress at proteomic level is still unclear. Here, both 200 mmol·L-1 CTS and distilled water were used to spray the leaves of vegetable soybean 'Lvlingtezao' seedlings. After 5 days of induction, NaCl stress and nutrient solution without NaCl were treated. Chloroplast proteins were extracted from leaves on the third day of NaCl treatment and analyzed by using the isobaric tags for relative and absolute quantification (iTRAQ). The result showed that CTS significantly increased net photosynthetic rate (Pn) of vegetable soybean seedlings under NaCl stress. Totally 549 reliable quantitative information proteins were identified, of which 442 existed in at least two biological repeats, including 26 up-regulated proteins and 4 down-regulated proteins associated with the effects of CTS on vegetable soybean response to NaCl stress. In addition, enrichment analysis of molecular function and metabolic pathway showed that up-regulated proteins were mainly related to molecular functions, including electron transport, chlorophyll binding, electron carrier activity, and were enriched in the pathways of photoreaction, carbon reaction and glyoxylic acid and dicarboxylic acid metabolism. Down-regulated proteins were mainly related to poly (U) RNA binding. Our results suggested that CTS could affect photosynthesis of vegetable soybean seedlings under NaCl stress through multiple pathways.

Influence of Slice Condition on the Distribution of Glyoxylic Acid in Human Hair

Influence of Slice Condition on the Distribution of Glyoxylic Acid in Human Hair

Selective Preparation of Glyoxylic Acid by Fast Pyrolysis of Cellulose Catalyzed with Nickel Nanoparticles

Selective Preparation of Glyoxylic Acid by Fast Pyrolysis of Cellulose Catalyzed with Nickel Nanoparticles

Electrocatalytic production of glycolic acid via oxalic acid reduction on titania debris supported on a TiO2 nanotube array

Electrodes prepared by anodic oxidation of Ti foils are robust and not toxic materials for the electrocatalytic reduction of oxalic acid to glycolic acid, allowing the development of a renewable energy-driven process for producing an alcoholic compound from an organic acid at low potential and room temperature. Coupled with the electrochemical synthesis of the oxalic acid from CO2, this process represents a new green and low-carbon path to produce added value chemicals from CO2. Various electrodes prepared by anodic oxidation of Ti foils were investigated. They were characterized by the presence of a TiO2 nanotube array together with the presence of small patches, debris, or TiO2 nanoparticles. The concentration of oxygen vacancies, the amount of Ti3+ measured by X-ray photoelectron spectroscopy (XPS) and the intensity of the anodic peak measured by cyclic voltammetry, were positively correlated with the achieved oxalic acid conversion and glycolic acid yield. The analysis of the results indicates the presence of small amorphous TiO2 nanoparticles (or surface patches or debris) interacting with TiO2 nanotubes, the sites responsible for the conversion of oxalic acid and glycolic acid yield. By varying this structural characteristic of the electrodes, it is possible to tune the glycolic acid to glyoxylic acid relative ratio. A best cumulative Faradaic efficiency (FE) of about 84% with FE to glycolic acid around 60% and oxalic conversion about 30% was observed.

Synthesis of Diaminoacetic Acid Derivatives as a Promising Scaffold for the Synthesis of Polyheterocyclic Cage Compounds.

Here, we explored in detail an acid-catalyzed condensation of glyoxylic acid or its ethyl ester with several carboxamides of different basicity, or with mesyl amide, to furnish diaminoacetic acid derivatives. The most suitable synthesis conditions and the reaction catalysts were identified. Properties such as structure and basicity of the starting amides were demonstrated to influence the condensation process. Elemental iodine was used for the first time herein as an acid catalyst for the condensation of glyoxylic acid or its ester, which gave access to diaminoacetic acid derivatives in higher yields in most cases, as opposed to p-toluenesulfonic acid (PTSA). An abnormally high activity of mesyl amide when condensed with ethyl glyoxylate was noticed, which may evidence a special impact of the sulfonyl moiety in the amide molecule on the condensation.

Exposure of Caenorhabditis elegans to Dietary Nε-Carboxymethyllysine Emphasizes Endocytosis as a New Route for Intestinal Absorption of Advanced Glycation End Products.

The impact of dietary advanced glycation end products (dAGEs) on human health has been discussed in many studies but, to date, no consensual pathophysiological process has been demonstrated. The intestinal absorption pathways which have so far been described for dAGEs, the passive diffusion of free AGE adducts and transport of glycated di-tripeptides by the peptide transporter 1 (PEPT-1), are not compatible with certain pathophysiological processes described. To get new insight into the intestinal absorption pathways and the pathophysiological mechanisms of dAGEs, we initiated an in vivo study with a so-called simple animal model with a complete digestive tract, Caenorhabditis elegans. Dietary bacteria were chemically modified with glyoxylic acid to mainly produce Nε-carboxymethyllysine (CML) and used to feed the worms. We performed different immunotechniques using an anti-CML antibody for the relative quantification of ingested CML and localization of this AGE in the worms’ intestine. The relative expression of genes encoding different biological processes such as response to stresses and intestinal digestion were determined. The physiological development of the worms was verified. All the results were compared with those obtained with the control bacteria. The results revealed a new route for the intestinal absorption of dietary CML (dCML), endocytosis, which could be mediated by scavenger receptors. The exposure of worms to dCML induced a reproductive defect and a transcriptional response reflecting oxidative, carbonyl and protein folding stresses. These data, in particular the demonstration of endocytosis of dCML by enterocytes, open up new perspectives to better characterize the pathophysiological mechanisms of dAGEs.

The influence of bioactive glyoxylate bearing Schiff base on antifungal and antioxidant activities to chitosan quaternary ammonium salts

In this study, to investigate the influence of glyoxylate bearing Schiff base on bioactivity to chitosan quaternary ammonium salts, different chitosan derivatives were synthesized by ion exchange of glyoxylate bearing Schiff base with chitosan quaternary ammonium salts (TMCI and HACC). For this purpose, glyoxylate was prepared by Schiff base reaction of glyoxylic acid and amino heterocycles and it was further ionization to substitute iodide ions and chloride ions. After structural characterization by FTIR and 1H NMR, the antifungal and antioxidant activities were measured. Results indicated that glyoxylate bearing Schiff base could improve the bioactivity of TMCI and HACC obviously. Specifically, anionic TMCI with Schiff base of amino pyridines possessed best antioxidant activity >92.40% at 1.6 mg/mL against DPPH radicals. Meanwhile, they showed antifungal activity >84.88% at 1.0 mg/mL against G. cingulate. Furthermore, the cytotoxicity was evaluated, and all samples showed good cell viability >80.14% at 1000 μg/mL.

Characteristics, Seasonality, and Secondary Formation Processes of Diacids and Related Compounds in Fine Aerosols During Warm and Cold Periods: Year‐Round Observations at Tianjin, North China

AbstractTo better understand the characteristics and sources of water‐soluble organic aerosols (OA) under different weather conditions, we collected fine aerosols (PM2.5) at an urban (ND) and a suburban (HEP) sites in Tianjin, North China over a 1‐year period and studied for diacids, oxoacids, and α‐dicarbonyls. Oxalic acid was found to be the most abundant (55.8 %± 10.7% at ND and 60.7% ± 13.0%) species during the campaign, followed by succinic and malonic acids, except for winter, in which phthalic acid was the third most abundant species at both the sites. Glyoxylic acid was found to be the most abundant (∼42%) oxoacids. Concentrations of diacids (range: 96.0–2137 ng m−3 at ND and 185–1227 ng m−3 at HEP) and related compounds were much higher in winter and lower in summer. Whereas the mass fractions of total diacids in PM2.5 and their carbon contents in TC, OC, and WSOC were 2–3 times higher in summer than that in winter. Based on seasonal variations in mass ratios, relative abundances and linear relations of selected marker species including nss‐K+, we found that water‐soluble OA over the Tianjin region were mainly derived from fossil fuel including coal combustion and biomass burning emissions and subsequent intensive photochemical processing in the atmosphere. The linear relations of diacids with ambient temperature, RH, SO42− and oxidants (O3 and NO2) and SO2 inferred that secondary formation and transformations of water‐soluble OA, particularly diacids and related compounds, in aqueous phase were more effective in cold period (October‐February), whereas in gas phase in warm period (March–September).

Study on serum metabolomics of combined injury induced by gas explosion in rats

Objective: To analyze the changes of serum metabolomics in rats with combined injuries caused by gas explosion and explore its possible mechanism. Methods: In April 2018, the large coal mine gas explosion test roadway and explosion test system were used to simulate the gas explosion experiment. All 32 SD rats were randomly divided into four groups, control group (not involved in the explosion) , close range (40 m) group, medium range (160 m) group and long range (240 m) group, 8 in each group. The respiratory function at 2 hours and the neural behavior at 48 hours were detected after the explosion. The rats were anesthetized and sacrificed after 48 hours, and the serum, lung, liver and other tissues of the rats were isolated and histopathological changes of lung and liver tissues were observed by HE staining. Serum samples were detected by liquid chromatography-high resolution mass spectrometry (UPLC-Orbitrap Elite/MS) , and metabolic spectrum differences between groups were evaluated by principal component analysis. Differential metabolites were screened and identified, and metabolic pathways were analyzed. Results: Compared with control group, respiratory function indexes (respiratory frequency, minute ventilation, peak inspiratory flow rate, peak expiratory flow rate and 1/2 tidal volume expiratory flow) of rats in different explosion groups were significantly decreased (P<0.05) , but respiration pause, inspiratory time and 2/3 tidal volume required time were significantly increased (P<0.05) in 2 hours after the explosion. However, the residence times of the neurobehavioral indicators of the 40 m group and 160 m group were significantly increased (P<0.05) , and the movement distances were significantly decreased (P<0.05) in 48 hours after the explosion. HE staining results showed that the lung and liver tissues of the rats in the gas explosion group structurally damaged, and the cells were disordered, with inflammatory cell infiltration, bleeding and edema. Metabonomics analysis showed that there were significant differences in metabolic profiles between groups. A total of 18 differential metabolites were identified in serum samples, including aconitum acid, citric acid, niacinamide and pyruvate, which involved in 12 major metabolic pathways, including the glutamic acid and glutamine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, glyoxylic acid and dicarboxylic acid metabolism, phenylalanine metabolism, nicotinic acid and nicotinamide metabolism, citric acid cycle (TCA cycle) . Conclusion: Gas explosion can cause multi-organ system damage in rats, the mechanism of which may be related to the biosynthesis of alanine, tyrosine and tryptophan, metabolism of niacin and niacinamide, metabolism of acetaldehyde and dicarboxylic acid, and TCA cycle, etc.

Controlled Formation of Carboxymethyllysine in Bone Matrix through Designed Glycation Reaction.

ABSTRACTIt has been a challenge to establish a link between specific advanced glycation end products (AGEs) as causal agents of different pathologies and age‐related diseases, primarily because of the lack of suitable in vitro experimental strategies facilitating increased formation of a specific AGE, here carboxymethyllysine (CML), over other AGEs under controlled conditions. CML is of considerable importance to various oxidative stress–related diseases, because in vivo formation of this AGE is connected with cellular oxidative/carbonyl metabolism. The mechanistic implications of CML accumulation in bone remain to be elucidated. To facilitate such studies, we developed a new in vitro strategy that allows preferential generation of CML in bone matrix over other AGEs. Using bone samples from human donors of different age (young, middle‐age, and elderly), we show successful in vitro generation of the desired levels of CML and show that they mimic those observed in vivo in several bone disorders. Formation of such physiologically relevant CML levels was achieved by selecting two oxidative/carbonyl stress compounds naturally produced in the human body, glyoxal and glyoxylic acid. Kinetic studies using the two compounds revealed differences not only between their reaction rates but also in the progression and enhanced formation of CML over other AGEs (measured by their collective fluorescence as fluorescent AGEs [fAGEs]) Consequently, through the regulation of reaction time, the levels of CML and fAGEs could be controlled and separated. Given that the developed approach does not fully eliminate the formation of other uncharacterized glycation products, this could be considered as the study limitation. We expect that the concepts of our experimental approach can be used to develop diverse strategies facilitating production of the desired levels of selected AGEs in bone and other tissues, and thus, opens new avenues for investigating the role and mechanistic aspects of specific AGEs, here CML, in bone. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Isobutanol tolerance and production of Saccharomyces cerevisiae can be improved by engineering its TATA-binding protein Spt15.

Low isobutanol tolerance of Saccharomyces cerevisiae limits its application in isobutanol fermentation. Here, we used global transcription machinery engineering to screen mutants with higher isobutanol tolerance and elevated isobutanol titres. TATA-binding protein Spt15 was used as the target of global transcription machinery engineering for improvement of such complex phenotypes. A random mutagenesis library of S. cerevisiae TATA-binding protein Spt15 was constructed and subjected to screening under isobutanol stress. A mutant strain (denoted as spt15-3) with improved isobutanol tolerance was identified. There were three mutations of Spt15 in strain spt15-3, including deletion of A at position -132 nt upstream of initiation codon, insertion of G at position -65 nt upstream of initiation codon and a synonymous mutation at position 315 nt (T → C) downstream of initiation codon. We then metabolically engineered isobutanol synthesis in strains harbouring plasmids YCplac22 containing these Spt15 mutations. Delta integration was used to overexpress ILV3 gene, and 2μ plasmids carrying PGK1p-ILV2 and PGK1p-ARO10 were used to overexpress ILV2 and ARO10 genes. After 24-h micro-aerobic fermentation, Engi-3 produced 0·556 g l-1 isobutanol, which was 404% and 25·3% greater than isobutanol produced by control Engi-1 and engineered Engi-2, respectively. After 28 h, Engi-4 produced 0·459 g l-1 isobutanol, which was 315% and 3·2% greater than isobutanol produced Engi-1 and Engi-2, respectively. RNA-Seq-based transcriptome analysis shows that mutations of Spt15 in strain spt15-3 increased the expression of SPT15. Meanwhile, compared with strain Engi-3, the spt15-3 mutation downregulated the expression of genes involved in the TCA cycle and glyoxylic acid cycle, but increased the expression of genes related to cell stability. This work demonstrates that isobutanol tolerance and production of S. cerevisiae can be improved by engineering its TATA-binding protein Spt15. This study clarified the molecular mechanisms regulating isobutanol production and tolerance in S. cerevisiae.

Diversified metabolism makes novel Thauera strain highly competitive in low carbon wastewater treatment

Thauera, as one of the core members of wastewater biological treatment systems, plays an important role in the process of nitrogen and phosphorus removal from low-carbon source sewage. However, there is a lack of systematic understanding of Thauera’s metabolic pathway and genomics. Here we report on the newly isolated Thauera sp. RT1901, which is capable of denitrification using variety carbon sources including aromatic compounds. By comparing the denitrification processes under the conditions of insufficient, adequate and surplus carbon sources, it was found that strain RT1901 could simultaneously use soluble microbial products (SMP) and extracellular polymeric substances (EPS) as electron donors for denitrification. Strain RT1901 was also found to be a denitrifying phosphate accumulating bacterium, able to use nitrate, nitrite, or oxygen as electron acceptors during poly-β-hydroxybutyrate (PHB) catabolism. The annotated genome was used to reconstruct the complete nitrogen and phosphorus metabolism pathways of RT1901. In the process of denitrifying phosphorus accumulation, glycolysis was the only pathway for glycogen metabolism, and the glyoxylic acid cycle replaced the tricarboxylic acid cycle (TCA) to supplement the reduced energy. In addition, the abundance of conventional phosphorus accumulating bacteria decreased significantly and the removal rates of total nitrogen (TN) and chemical oxygen demand (COD) increased after the addition of RT1901 in the low carbon/nitrogen (C/N) ratio of anaerobic aerobic anoxic-sequencing batch reactor (AOA-SBR). This research indicated that the diverse metabolic capabilities of Thauera made it more competitive than other bacteria in the wastewater treatment system.

Palladium‐Catalyzed Decarboxylative 1,2‐Addition of Carboxylic Acids to Glyoxylic Acid Esters

AbstractThe formation of C−C‐bonds constitutes one of the most fundamental synthetic operations in organic chemistry. The nucleophilic addition of preformed organometallic reagents to an electrophilic carbonyl functionality represents a classical method for the selective construction of a C−C‐bond. However, the synthesis and utilization of an organometallic reagent is associated with an unfavorable environmental profile. Herein, we disclose a Palladium‐catalyzed decarboxylative 1,2‐addition of carboxylic acids to glyoxylic acid esters. This novel method provides access to the mandelic acid scaffold in good yields. Easy‐to‐handle and readily available benzoic acids are utilized as more sustainable alternative to preformed organometallic nucleophiles.