Yield Of Acetate Research Articles

Modulation of Albumin Esterase Activity by Warfarin and Diazepam

Data are accumulating on the hydrolytic activity of serum albumin towards esters and organophosphates. Previously, with the help of the technology of proton nuclear magnetic resonance (1H NMR) spectroscopy, we observed the yield of acetate in the solution of bovine serum albumin and p-nitrophenyl acetate (NPA). Thus, we showed that albumin possesses true esterase activity towards NPA. Then, using the methods of molecular docking and molecular dynamics, we established site Sudlow I as the catalytic center of true esterase activity of albumin. In the present work, to expand our understanding of the molecular mechanisms of albumin pseudoesterase and true esterase activity, we investigated—in experiments in vitro and in silico—the interaction of anticoagulant warfarin (WRF, specific ligand of site Sudlow I) and benzodiazepine diazepam (DIA, specific ligand of site Sudlow II) with albumins of different species, and determined how the binding of WRF and DIA affects the hydrolysis of NPA by albumin. It was found that the characteristics of the binding modes of WRF in site Sudlow I and DIA in site Sudlow II of human (HSA), bovine (BSA), and rat (RSA) albumins have species differences, which are more pronounced for site Sudlow I compared to site Sudlow II, and less pronounced between HSA and RSA compared to BSA. WRF competitively inhibits true esterase activity of site Sudlow I towards NPA and does not affect the functioning of site Sudlow II. Diazepam can slow down true esterase activity of site Sudlow I in noncompetitive manner. It was concluded that site Sudlow I is more receptive to allosteric modulation compared to site Sudlow II.

13C-Labelled Glucose Reveals Shifts in Fermentation Pathway During Cathodic Electro-Fermentation with Mixed Microbial Culture.

Cathodic Electro-Fermentation (CEF) is an innovative approach to manage the spectrum of products deriving from anaerobic fermentation. Herein, mixed microbial culture fermentation using a ternary mixture containing labelled 13C glucose and non-labelled acetate and ethanol was studied to identify the role of polarization on the metabolic pathways of glucose fermentation. CEF at an applied potential of -700 mV (vs. SHE, Standard Hydrogen Electrode) enhanced the production yield of acetate, propionate, and butyrate (0.90±0.10, 0.22±0.03, and 0.34±0.05 mol/mol; respectively) compared to control tests performed at open circuit potential (OCP) (0.54±0.09, 0.15±0.04, and 0.20±0.001 mol/mol, respectively). Results indicate that CEF affected the 13C labelled fermented product levels and their fractional 13C enrichments, allowing to establish metabolic pathway models. This work demonstrates that, under cathodic polarization, the abundance of both fully 13C labelled propionate and butyrate isotopomers increased compared to control tests. The effect of CEF is mainly due to intermediates initially produced from the glucose metabolic transformation in the presence of non-labelled acetate and ethanol as external substrates. These findings represent a significant advancement in current knowledge of CEF, which offers a promising tool to control mixed cultures bioprocesses.

Mechanistic insights into ethylene catalytic combustion and CO2 formation in vinyl acetate synthesis

Vinyl acetate is a crucial monomer for the production of polyvinyl alcohol and polyvinyl acetate, with extensive applications in the photovoltaic and pharmaceutical industries. CO2 is the primary by-product in the synthesis of vinyl acetate, significantly burdening the separation process and impacting the ecological environment. Reducing CO2 generation at the source is an effective solution. In the vinyl acetate synthesis process, CO2 is primarily produced through the catalytic combustion of ethylene. However, the reaction mechanism of ethylene catalytic combustion on Pd-based catalysts in vinyl acetate synthesis remains incomplete, with existing mechanisms presenting certain limitations. Therefore, further investigation into the reaction mechanism of ethylene catalytic combustion leading to CO2 formation on Pd-based catalysts is necessary.This study employs density functional theory to calculate the reaction mechanism of ethylene catalytic combustion on the Pd(100) surface, obtaining elementary reaction kinetics data. Based on these data, the kinetic Monte Carlo method was used to investigate the reaction process of ethylene catalytic combustion, revealing the predominant pathway for CO2 formation. This research provides targeted strategies for catalyst modification. It aims to improve the understanding of the reaction mechanism of ethylene catalytic combustion in vinyl acetate synthesis, reduce the consumption of ethylene in by-product formation, enhance vinyl acetate yield and ethylene utilization, and ultimately decrease CO2 production, thereby lowering carbon emissions.

Enhanced Enzymatic Performance of Immobilized Pseudomonas fluorescens Lipase on ZIF-8@ZIF-67 and Its Application to the Synthesis of Neryl Acetate with Transesterification Reaction.

In this study, hybrid skeleton material ZIF-8@ZIF-67 was synthesized by the epitaxial growth method and then was utilized as a carrier for encapsulating Pseudomonas fluorescens lipase (PFL) through the co-precipitation method, resulting in the preparation of immobilized lipase (PFL@ZIF-8@ZIF-67). Subsequently, it was further treated with glutaraldehyde to improve protein immobilization yield. Under optimal immobilization conditions, the specific hydrolytic activity of PFL@ZIF-8@ZIF-67 was 20.4 times higher than that of the free PFL. The prepared biocatalyst was characterized and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR). Additionally, the thermal stability of PFL@ZIF-8@ZIF-67 at 50 °C was significantly improved compared to the free PFL. After 7 weeks at room temperature, PFL@ZIF-8@ZIF-67 retained 78% of the transesterification activity, while the free enzyme was only 29%. Finally, PFL@ZIF-8@ZIF-67 was applied to the neryl acetate preparation in a solvent-free system, and the yield of neryl acetate reached 99% after 3 h of reaction. After 10 repetitions, the yields of neryl acetate catalyzed by PFL@ZIF-8@ZIF-67 and the free PFL were 80% and 43%, respectively.

Immobilized lipase based on SBA-15 adsorption and gel embedding for catalytic synthesis of isoamyl acetate

In this study, Candida rugosa lipase (CRL) was immobilized on the silica carrier SBA-15 by physical adsorption, then mixed with hydrophobically modified sodium alginate and dropped into calcium chloride solution. Finally, the adsorption-embedding immobilized lipase (L-SBA-15-Mgel) was successfully prepared. The conformation of the carrier before and after lipase immobilization were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and other characterization techniques. The molecular docking and molecular dynamics simulation of CRL and modifier dodecyl glycidyl ether (DGE) ligand were carried out to analyze the potential influence of modifier on enzyme characteristics. The basic enzymatic properties including the activity, stability and reaction kinetic parameters of the immobilized lipase L-SBA-15-Mgel were studied. L-SBA-15-Mgel showed good storage stability and reusability. After 16 days of storage, the activity retention was 47.85%, and there was still 63.20% of the residual activity after seven cycles of reuse. The immobilized lipase was applied to the efficient synthesis of food flavor ester isoamyl acetate. Under the reaction conditions of 50 °C and 200 rpm, the highest yield of isoamyl acetate catalyzed by L-SBA-15-Mgel was 85.19%.

ZnMo-MOF as anti-CO hydrogen electrocatalyst enhance microbial electrosynthesis for CO/CO2 conversion

Microbial electrosynthesis (MES) is an electrically driven technology that can be used for converting CO/CO2 into chemicals. The unique electronic and substrate properties of CO make it an important research target for MES. However, CO can poison the cathode and increase the overpotential of hydrogen evolution reaction (HER), thus reducing the electron transfer rate via H2. This work evaluated the effect of an anti-CO HER catalyst on the performance of MES for CO/CO2 conversion. ZnMo-metal–organic framework (MOF) materials with different calcination temperatures were synthesized. ZnMo-MOF-800 with Mo2C nanoparticles as active centers exhibited excellent resistance to CO toxicity. It also obtained the highest hydrogen evolution and enhanced electron transfer rate in CO atmosphere. MES with ZnMo-MOF-800 cathode and Clostridium ljungdahlii as biocatalyst obtained 0.31 g L−1 d−1 acetate yield, 0.1 g L−1 d−1 butyrate yield, and 0.09 g L−1 d−1 2,3-butanediol yield in CO/CO2, while Pt/C only get 0.076 g L−1 d−1 acetate yield, 0.05 g L−1 d−1 butyrate yield and 0.02 g L−1 d−1 2,3-butanediol yield. ZnMo-MOF-800 was conducive to biofilm formation, enabling it to better resist CO toxicity. This work provides new opportunities for constructing a highly efficient cathode with an anti-CO hydrogen evolution catalyst to enhance CO/CO2 conversion in MES.

Carcass and non-carcass component yields of trenbolone acetate + estradiol-17β implanted steers vs. non-implanted steers across serial harvest endpoints

ObjectiveWe investigated incremental growth of carcass and non-carcass components and tissue partitioning of implanted or non-implanted steers. Materials and MethodsSteers (n = 80; 271 ± 45 kg) were paired and randomized to harvest date (d 0, 42, 84, 126, 168, 210, 252, 294, 336, or 378), and individuals within pairs were randomized to CON (negative control) or REV (Revalor-XS, Merck Animal Health, on d 0 and 190) treatments. Non-carcass components were removed, cleaned, and weighed. Growth coefficients were calculated using the allometric equation Y = bXa. Results and DiscussionEmpty body weight (EBW), and hot carcass weight (HCW) were 6% greater (P < 0.01) in REV steers versus CON. No treatment effects (P ≥ 0.12) occurred for fill or dressed carcass yield (DY); however, EBW, HCW, and DY increased (P ≤ 0.01) and percentage fill decreased as an effect of days on feed (DOF). Absolute fill weight did not change across DOF (P = 0.82). Implanted steers had greater (P ≤ 0.05) absolute mass of blood, head, hide, oxtail, liver, spleen, bladder, heart, reticulum, omasum, stomach, small intestine, intestines, gastrointestinal tract (GIT), total splanchnic tissue, and total offal. Implanted steers also had smaller (P ≤ 0.05) absolute mass of thymus glands and kidney-pelvic- heart fat (KPH) than non-implanted steers. Non-carcass components with lowest growth coefficients included small intestine (0.02), large intestine (0.12), and brain and spinal cord (0.13). However, KPH (2.01) accumulated at more than 2 times the rate of the empty body, whereas cod fat (1.42) and GIT fat (1.61) grew notably faster than the empty body. Implication and ApplicationsResults suggest that Revalor-XS increased body and carcass weights and altered many non-carcass components and their growth co- efficients, ultimately playing key biological, nutritional, and financial roles across sectors of the beef industry.

Insights into intraspecific diversity of central carbon metabolites in Saccharomyces cerevisiae during wine fermentation

Saccharomyces cerevisiae is a major actor in winemaking that converts sugars from the grape must into ethanol and CO2 with outstanding efficiency. Primary metabolites produced during fermentation have a great importance in wine. While ethanol content contributes to the overall profile, other metabolites like glycerol, succinate, acetate or lactate also have significant impacts, even when present in lower concentrations. S. cerevisiae is known for its great genetic diversity that is related to its natural or technological environment. However, the variation range of metabolic diversity which can be exploited to enhance wine quality depends on the pathway considered. Our experiment assessed the diversity of primary metabolites production in a set of 51 S. cerevisiae strains from various genetic backgrounds. Results pointed out great yield differences depending on the metabolite considered, with ethanol having the lowest variation. A negative correlation between ethanol and glycerol was observed, confirming glycerol synthesis as a suitable lever to reduce ethanol yield. Genetic groups were linked to specific yields, such as the wine group and high α-ketoglutarate and low acetate yields. This research highlights the potential of using natural yeast diversity in winemaking. It also provides a detailed data set on production of well known (ethanol, glycerol, acetate) or little-known (lactate) primary metabolites.

Genome-scale metabolic modeling of the human milk oligosaccharide utilization by Bifidobacterium longum subsp. infantis.

Bifidobacterium longum subsp. infantis is a representative and dominant species in the infant gut and is considered a beneficial microbe. This organism displays multiple adaptations to thrive in the infant gut, regarded as a model for human milk oligosaccharides (HMOs) utilization. These carbohydrates are abundant in breast milk and include different molecules based on lactose. They contain fucose, sialic acid, and N-acetylglucosamine. Bifidobacterium metabolism is complex, and a systems view of relevant metabolic pathways and exchange metabolites during HMO consumption is missing. To address this limitation, a refined genome-scale network reconstruction of this bacterium is presented using a previous reconstruction of B. infantis ATCC 15967 as a template. The latter was expanded based on an extensive revision of genome annotations, current literature, and transcriptomic data integration. The metabolic reconstruction (iLR578) accounted for 578 genes, 1,047 reactions, and 924 metabolites. Starting from this reconstruction, we built context-specific genome-scale metabolic models using RNA-seq data from cultures growing in lactose and three HMOs. The models revealed notable differences in HMO metabolism depending on the functional characteristics of the substrates. Particularly, fucosyl-lactose showed a divergent metabolism due to a fucose moiety. High yields of lactate and acetate were predicted under growth rate maximization in all conditions, whereas formate, ethanol, and 1,2-propanediol were substantially lower. Similar results were also obtained under near-optimal growth on each substrate when varying the empirically observed acetate-to-lactate production ratio. Model predictions displayed reasonable agreement between central carbon metabolism fluxes and expression data across all conditions. Flux coupling analysis revealed additional connections between succinate exchange and arginine and sulfate metabolism and a strong coupling between central carbon reactions and adenine metabolism. More importantly, specific networks of coupled reactions under each carbon source were derived and analyzed. Overall, the presented network reconstruction constitutes a valuable platform for probing the metabolism of this prominent infant gut bifidobacteria.IMPORTANCEThis work presents a detailed reconstruction of the metabolism of Bifidobacterium longum subsp. infantis, a prominent member of the infant gut microbiome, providing a systems view of its metabolism of human milk oligosaccharides.

Co3O4/C derived from ZIF-67 cathode enhances the microbial electrosynthesis of acetate from CO2

Microbial Electrosynthesis (MES) is an electrochemical reduction technology that efficiently converts CO2 into chemicals by electrically driving microbial catalysts. However, the lower mass transfer efficiency of CO2 and hydrogen H2 affected the performance of the MES. In this study, Co3O4/C is derived from the carbonization of ZIF-67 with different temperature (700 °C,800 °C,900 °C), in which some Co ions are exposed and a large number of catalytically active sites are supplied. Among them, the Co3O4/C with 800 °C had the highest hydrogen evolution reaction activity and the lowest internal resistance. The Co3O4/C with 800 °C showed the highest hydrogen production rate of 81.34 × 102 mol day−1, which was 4.4 times higher than that of the bare carbon felt. Furthermore, the Co3O4/C with 800 °C modified cathode was beneficial to the formation of biofilm and improved the enrichment of Acetobacterium and Arcobacter. The highest acetate yield of 0.19 g L−1d−1 was obtained by Co3O4/C with 800 °C, which was 2.1 times higher than that of bare carbon felt, and the corresponding acetate concentration reached 5.61 ± 0.1 g L−1. Co3O4/C derived from ZIF-67 with good H2 production and CO2 adsorption ability is an effective strategy to improve MES cathode.

Extractive fermentation as a strategy to increase the co-production of H2 and carboxylates in dark fermentation

Ion exchange resins were used to remove carboxylates from a dark fermentation batch reactor to enhance hydrogen (H2) and carboxylate production. Three anion exchange resins were tested. The A110 resin (macroporous, primary amine functionalized) was selected as suitable for carboxylates removal due to its total exchange capacity (1.25 ± 0.12 mmol/g) and affinity towards butyrate. The extractive fermentation system included a column packed with the A110 resin which was connected to a batch-stirred tank H2 reactor. This setup achieved 3762.9 ± 229.1 NmL H2/L of total accumulated H2 volume, equivalent to a 15.2 % increase compared with the control experiment (3288.6 ± 279.0 NmL H2/L). Also, the molar yields of acetate (0.81 ± 0.11 mol/mol hexose) and butyrate (1.01 ± 0.21 mol/mol hexose) increased by 62.7 % and 71.3 %, respectively. The extractive fermentation system could dampen the inhibitory processes by product accumulation and possibly favor a change in the metabolism of dark fermentation microbial communities that enhanced the production of butyrate and H2 from lactate and acetate. Future studies might guarantee molecular analysis of the microbial communities in extractive fermentation as well testing different extraction systems.

Improved Short-Chain Fatty Acids Production and Protein Degradation During the Anaerobic Fermentation of Waste-Activated Sludge via Alumina Slag-Modified Biochar.

As the by-product in the biological sewage treatment, waste-activated sludge (WAS) always suffers from the difficulty of disposal. Anaerobic fermentation to achieve valuable carbon sources is a feasible way for resource utilization of WAS, whereas the process is always restricted by its biochemical efficiency. Hence, the WAS was used as the feedstock in this study. Alumina slag-modified biochar (Al@BioC) respectively from pine wood (PW) or fresh vinegar residue (FVR) was employed to stimulate the process of short-chain fatty acids (SCFAs) production during the anaerobic treatment of WAS. The results indicate that the addition of Al@BioC could facilitate the distinct increase in SCFAs yield (42.66 g/L) by 14.09% and acetate yield (33.30 g/L) by 18.77%, respectively, when compared with that in regular fermentation without Al@BioC addition. Furthermore, protein degradation was also improved. With the Al@BioCPW added, the maximum concentration of soluble protein reached 867.68 mg/L and was 24.39% higher than the initial level, while the enhancement in the group with Al@BioCFVR and without biochar addition was 12.49% and 7.44%, respectively. According to the results of 16S rDNA sequencing, the relative abundance of acid-producing bacteria (Bacteroidota and Firmicutes) was enriched, enhancing the pathways of protein metabolisms and the ability to resist the harsh environment, respectively. Moreover, Proteiniphilum under Bacteroidota and Fastidiosipila under Firmicutes were the main microorganisms to metabolize protein. The above results might provide a novel material for harvesting the SCFAs production, which is conducive to harmless disposal and carbon resource recovery.

Continuously Producing Highly Concentrated and Pure Acetic Acid Aqueous Solution via Direct Electroreduction of CO2.

It is crucial to achieve continuous production of highly concentrated and pure C2 chemicals through the electrochemical CO2 reduction reaction (eCO2RR) for artificial carbon cycling, yet it has remained unattainable until now. Despite one-pot tandem catalysis (dividing the eCO2RR to C2 into two catalytical reactions of CO2 to CO and CO to C2) offering the potential for significantly enhancing reaction efficiency, its mechanism remains unclear and its performance is unsatisfactory. Herein, we selected different CO2-to-CO catalysts and CO-to-acetate catalysts to construct several tandem catalytic systems for the eCO2RR to acetic acid. Among them, a tandem catalytic system comprising a covalent organic framework (PcNi-DMTP) and a metal-organic framework (MAF-2) as CO2-to-CO and CO-to-acetate catalysts, respectively, exhibited a faradaic efficiency of 51.2% with a current density of 410 mA cm-2 and an ultrahigh acetate yield rate of 2.72 mmol m-2 s-1 under neutral conditions. After electrolysis for 200 h, 1 cm-2 working electrode can continuously produce 20 mM acetic acid aqueous solution with a relative purity of 95+%. Comprehensive studies revealed that the performance of tandem catalysts is influenced not only by the CO supply-demand relationship and electron competition between the two catalytic processes in the one-pot tandem system but also by the performance of the CO-to-C2 catalyst under diluted CO conditions.

Preparation and synbiotic interaction mechanism of microcapsules of Bifidobacterium animalis F1–7 and human milk oligosaccharides (HMO)

Probiotics such as Bifidobacterium spp. generally possess important physiological functions. However, maintaining probiotic viability is a challenge during processing, storage, and digestive transit period. Microencapsulation is widely considered to be an attractive approach. In this study, B. animalis F1–7 microcapsules and B. animalis F1–7-HMO microcapsules were successfully prepared by emulsification/internal gelation with high encapsulation efficiency (90.67 % and 92.16 %, respectively). The current study revealed that HMO-supplemented microcapsules exhibited more stable lyophilized forms and thermal stability. Additionally, a significant improvement in probiotic cell viability was observed in such microcapsules during simulated gastrointestinal (GI) fluids or storage. We also showed that the individual HMO mixtures 6′-SL remarkably promoted the growth and acetate yield of B. animalis F1–7 for 48 h (p < 0.05). The synbiotic combination of 6′-SL with B. animalis F1–7 enhanced SCFAs production in vitro fecal fermentation, decreasing several harmful intestinal bacteria such as Dorea, Escherichia-Shigella, and Streptococcus while enriching the probiotic A. muciniphila. This study provides strong support for HMO or 6′-SL combined with B. animalis F1–7 as an innovative dietary ingredient to bring health benefits. The potential of the synbiotic microcapsules with this combination merits further exploration for future use in the food industry.

Selective syngas fermentation to acetate under acidic and psychrophilic conditions using mixed anaerobic culture

Syngas fermentation to acetate offers a promising solution for its valorisation, particularly when syngas contains a high N2 concentration, which otherwise impedes the utilisation of syngas biomethanation gaseous product in cogeneration or upgrading units. In this study, continuous lab-scale syngas fermentation assessing the effects of acidic pH and psychrophilic conditions (28 °C and 20 °C) on bioconversion efficiency and anaerobic consortium diversity was studied. The results showed that as temperature and pH decrease, acetate yield increases. The highest H2 and CO consumption rates were observed at 20 °C and pH 4.5, reaching 48.4 mmol/(L·d) and 31.5 mmol/(L·d), respectively, and methanogenic activity was not completely suppressed. The microbial community composition indicated an enhanced abundance of acetate-producing bacteria and hydrogenotrophic methanogens at 28 °C. The PICRUSt2 prediction of metabolic potential indicated that temperature and pH changes appear to have a more pronounced impact on acetotrophic methanogenesis genes than carbon dioxide-based methanogenesis genes.

Housing of electrosynthetic biofilms using a roll-up carbon veil electrode increases CO2 conversion and faradaic efficiency in microbial electrosynthesis cells

Electrode-driven microbial electron transfer enables the conversion of CO2 into multi-carbon compounds. The electrosynthetic biofilms grow slowly on the surface and are highly susceptible to operational influences, such as hydrodynamic shear stress. In this study, a cylindrical roll-up carbon felt electrode was developed as a novel strategy to protect biofilms from shear stress within the reactor. The fabricated electrode allowed hydrogen bubble formation inside the structure, which enabled microbes to uptake hydrogen and convert CO2 to multi-carbon organic compounds. The roll-up electrode exhibited faster start-up and biofilm formation than the conventional linear shape carbon felt. The acetate yield and cathodic faradaic efficiency increased by 80% and 34%, respectively, and the bioelectrochemical stability was improved significantly. The roll-up structure increased biofilm development per unit electrode surface by three to five-fold. The roll-up configuration improved biofilm formation on the electrode, which enhanced the performance of microbial electrosynthesis-based CO2 valorization.

Cathode materials in microbial electrosynthesis systems for carbon dioxide reduction: recent progress and perspectives

Microbial electrosynthesis (MES) is an emerging technology that enables the synthesis of value-added chemicals from carbon dioxide (CO2) or inorganic carbon compounds by coupling renewable electricity to microbial metabolism. However, MES still faces challenges in achieving high production of value-added chemicals due to the limited extracellular electron transfer efficiency at the biotic-abiotic interfaces. To overcome this bottleneck, it is crucial to develop novel cathodes and modified materials. This review systematically summarizes recent advancements in cathode materials in the field of electrocatalyst-assisted and photocatalyst-assisted MES. The effects of various material types are further investigated by comparing metal-free and metal materials and photocatalyst materials of different semiconductor types. Additionally, the review introduces the maximum production rate of value-added chemicals and conversion efficiency achieved by these cathode materials while highlighting the advantages and disadvantages of different material types. To the best of our knowledge, in electrocatalyst-assisted systems, the maximum CH4 yield on graphene aerogel/polypyrrole cathode achieved 1,672 mmol m-2 d-1, and the maximum Faraday efficiency (FE) of CH4 reached up to 97.5% on graphite plate. Meanwhile, the maximum acetate yield achieved 1,330 g m-2 d-1 with CO2 conversion efficiency into acetate close to 100% on carbon nanotube cathodes. In photocatalyst-assisted systems, the maximum acetate yield could reach 0.51 g L-1 d-1 with the coulombic efficiency of 96% on the MnFe2O4/g-C3N4 photocathode. Finally, prospects for future development and practical applications of MES are discussed, offering theoretical guidance for the fabrication of cathode materials that can improve production efficiency and reduce energy input.

Directing the Selectivity of CO Electrolysis to Acetate by Constructing Metal-Organic Interfaces.

Electrochemically converting CO2 to valuable chemicals holds great promise for closing the anthropogenic carbon cycle. Owing to complex reaction pathways and shared rate-determining steps, directing the selectivity of CO2 /CO electrolysis to a specific multicarbon product is very challenging. We report here a strategy for highly selective production of acetate from CO electrolysis by constructing metal-organic interfaces. We demonstrate that the Cu-organic interfaces constructed by in situ reconstruction of Cu complexes show very impressive acetate selectivity, with a high Faradaic efficiency of 84.2 % and a carbon selectivity of 92.1 % for acetate production, in an alkaline membrane electrode assembly electrolyzer. The maximum acetate partial current density and acetate yield reach as high as 605 mA cm-2 and 63.4 %, respectively. Thorough structural characterizations, control experiments, operando Raman spectroscopy measurements, and density functional theory calculation results indicate that the Cu-organic interface creates a favorable reaction microenvironment that enhances *CO adsorption, lowers the energy barrier for C-C coupling, and facilitates the formation of CH3 COOH over other multicarbon products, thus rationalizing the selective acetate production.

Directing the Selectivity of CO Electrolysis to Acetate by Constructing Metal‐Organic Interfaces

AbstractElectrochemically converting CO2 to valuable chemicals holds great promise for closing the anthropogenic carbon cycle. Owing to complex reaction pathways and shared rate‐determining steps, directing the selectivity of CO2/CO electrolysis to a specific multicarbon product is very challenging. We report here a strategy for highly selective production of acetate from CO electrolysis by constructing metal‐organic interfaces. We demonstrate that the Cu‐organic interfaces constructed by in situ reconstruction of Cu complexes show very impressive acetate selectivity, with a high Faradaic efficiency of 84.2 % and a carbon selectivity of 92.1 % for acetate production, in an alkaline membrane electrode assembly electrolyzer. The maximum acetate partial current density and acetate yield reach as high as 605 mA cm−2 and 63.4 %, respectively. Thorough structural characterizations, control experiments, operando Raman spectroscopy measurements, and density functional theory calculation results indicate that the Cu‐organic interface creates a favorable reaction microenvironment that enhances *CO adsorption, lowers the energy barrier for C−C coupling, and facilitates the formation of CH3COOH over other multicarbon products, thus rationalizing the selective acetate production.

Transcriptomic and metabonomic to evaluate the effect mechanisms of the growth and aroma-producing of Pichia anomala under ethanol stress

Ethanol stress is an important environmental factor that affects physiological metabolism and aroma-producing capacity of yeast during the brewing process of alcoholic products. To explore the mechanisms of the growth and aroma-producing metabolism of Pichia anomala under ethanol stress, transcriptomic and metabolomic results were collected from different concentrations (3%, 6% and 9%) of the ethanol stressor, and genes, metabolites and metabolic pathways that relate to growth and aroma-producing were screened. Integrated transcriptomic and metabolomic results showed that P. anomala could respond to ethanol stress by activating purine and pyrimidine, glycerophospholipid and antioxidant metabolic pathways. However, the damage to the growth of P. anomala under ethanol stress was closely related to the inhibition of carbohydrate metabolism, ABC transporter, energy metabolism and amino acid pathways, the influence on these pathways became more serious with the increase of ethanol concentrations. Meantime, the decrease in production of phenethyl alcohol and isoamyl alcohol was related to the significantly down-regulated of ARO9, ARO10, ADH1 and ADH2 genes expression in phenylalanine, tyrosine and tryptophan, and glycolysis pathways of P. anomala under ethanol stress. The enhanced expression of ATF1, EAT1, EEB1 and TGL2 genes in P. anomala was the main reason for the high yield of ethyl caproate and ethyl acetate under ethanol stress. These results revealed a theoretical basis for further study of the effect mechanisms of ethanol stress on P. anomala and molecular targets for the construction of genetic engineering strains with high ethanol tolerance and high aroma production.