Production Of Acetone Research Articles

Engineering Acetobacterium wieringae for acetone production from syngas

Gas fermentation using acetogenic bacteria offers a sustainable alternative to fossil-based chemical production by converting waste gas streams, such as syngas (CO, H2, CO2), into valuable biocommodities. In this study, strain JM, a novel isolate of the acetogen Acetobacterium wieringae was engineered for autotrophic acetone production. Novel constitutive promoters native to A. wieringae JM were identified and characterized, expanding the genetic toolbox for this organism. These promoters, along with previously described promoters from Clostridium autoethanogenum, were used to control the expression of acetone production operon from C. acetobutylicum, leading to significant improvements in acetone titers. The use of multiple transcriptional units (TUs) for pathway gene expression further enhanced acetone production compared to a single operon. Additionally, the acetoacetyl-CoA acetate/butyrate CoA-transferase enzyme from C. beijerinckii was found to improve acetone production compared to its homolog from C. acetobutylicum. The plasmid-based expression system using the pMTL83151 vector (pCB102 replicon) demonstrated segregational stability and a consistent single-copy number under both selective and non-selective conditions. Fermentation conditions were optimized, with buffer capacity and gas availability identified as critical factors in batch fermentations. The physiology of autotrophic acetone production was further assessed utilizing different gas compositions which significantly impacted carbon flux to acetone. Under optimized conditions with a 20 % CO syngas blend, the engineered A. wieringae JM [pAW_PFTL-APO] strain achieved an acetone titer of 41.3 mM. This study establishes A. wieringae JM as a promising platform for sustainable acetone production from waste gases and provides a foundation for further development of gas-based biorefineries.

Propane wet reforming over PtSn nanoparticles on γ-Al2O3 for acetone synthesis

Acetone serves as an important solvent and building block for the chemical industry, but the current industrial synthesis of acetone is generally accompanied by the energy-intensive and costly cumene process used for phenol production. Here we propose a sustainable route for acetone synthesis via propane wet reforming at a moderate temperature of 350 oC with the use of platinum-tin nanoparticles supported on γ-aluminium oxide (PtSn/γ-Al2O3) as catalyst. We achieve an acetone productivity of 858.4 μmol/g with a selectivity of 57.8% among all carbon-based products and 99.3% among all liquid products. Detailed spectroscopic and controlled experiments reveal that the acetone is formed through a tandem catalytic process involving propene and isopropanol as intermediates. We also demonstrate facile ketone synthesis via wet reforming with the use of different alkanes (e.g., n-butane, n-pentane, n-hexane, n-heptane, and n-octane) as substrates, proving the wide applicability of this strategy.

Platinum(II) acetimino cyclometalated complexes derived from room temperature ammonia activation

Two Pt(II) rollover cyclometalated complexes, [Pt(bpyPh‐H)(DMSO)Me] (1) and [Pt(bpyPh‐H)(DMSO)Cl] (2), where bpyPh‐H is the C3‐deprotonated 6‐phenyl‐2,2’‐bipyridine, were reacted with aqueous ammonia in acetone at room temperature. In the case of the electron‐poor complex 2 simple substitution of DMSO gave the amino complex [Pt(bpyPh‐H)(NH3)Cl] (4), whereas the electron‐rich complex 1 produced the rare acetimine complex [Pt(bpyPh‐H)(HN=CMe2)Me] (3), stable both in solution and in the solid state. The result is noteworthy, as the condensation product of acetone and ammonia, acetimine, is not stable under mild conditions. The reaction likely requires a Pt(II) electron‐rich complex and the presence of a carbon donor in trans position. An analogous reaction occurs with methylamine, allowing the synthesis of the secondary imine complex [Pt(bpyPh‐H)(MeN=CMe2)Me], 5. Starting from this finding a series of cyclometalated acetimine complexes [Pt(N^C)(HN=CMe2)Me] were isolated and characterized with other classical and rollover cyclometalated ligands with an array of different electronic and steric properties, indicating a possible extension of the reaction to various cyclometalated ligands. A preliminary study on the antimicrobial and antitumor properties of complex 3, taken as a model for this class, showed no significant effects against Gram‐positive, Gram‐negative bacteria, or yeasts, but found activity in vitro against HT29 colon cancer cell line.

Enhanced biobutanol production with sustainable Co-substrates synergy from paper waste and garden waste with municipal biowaste

Synergy in the co-processing of lignocellulosic wastes and municipal biowaste (MB) can unlock their potential for biobutanol production. This study assessed the potential for biobutanol production through the co-processing of lignocellulosic waste and MB. Specifically, it compared the co-processing of paper waste with MB to that of garden waste and MB. Ethanol organosolv pretreatment served as a dual-function process for both pretreatment and detoxification purposes. Initial fermentation of hydrolysates from untreated paper waste using Clostridium acetobutylicum produced 0.9 g/L of acetone and ethanol but no detectable butanol. Organosolv pretreatment led to a significant increase in acetone and ethanol production but did not yield butanol. Co-processing paper waste with MB using organosolv pretreatment resulted in the production of 2.8–3.2 g/L butanol, along with increased acetone and ethanol production. Furthermore, co-processing a 1:1 (w/w) mixture of paper waste and MB under mild and severe pretreatment conditions produced 45.5 g and 43.4 g butanol, respectively, compared to 34.8 g and 14.4 g butanol when processing these waste streams separately. The study also explored the positive impact of co-processing garden waste with MB, a distinct lignocellulosic source, enhancing acetone-butanol-ethanol (ABE) yield by 27–40%. These findings highlight the potential of synergistic waste co-processing for achieving a more suitable balance of nutrients to enhance biobutanol and ABE production from biowastes. Additionally, the simultaneous treatment of lignocellulosic waste and municipal biowaste offers a simplified approach to waste processing, contributing to advancements in sustainable biomass utilization and bioenergy production.

Assessing acetone for the GISS ModelE2.1 Earth system model

Abstract. Acetone is an abundant volatile organic compound (VOC) in the atmosphere, with important influences on ozone and oxidation capacity. Direct sources include chemical production from other VOCs and anthropogenic emissions, terrestrial vegetation, biomass-burning emissions, and ocean production. Sinks include chemical loss, deposition onto the land surface, and ocean uptake. Acetone also has a lifetime that is long enough to allow transport and reactions with other compounds remote from its sources. The NASA Goddard Institute for Space Studies (GISS) Earth system model ModelE2.1 simulates a variety of Earth system interactions. Previously, acetone had a very simplistic representation in the ModelE chemical scheme. This study assesses a more sophisticated acetone scheme in which acetone is a full 3-dimensional tracer with explicit sources, sinks, and atmospheric transport. We first evaluate the new global acetone budget in the context of past literature. Estimated source and sink fluxes fall within the range of previous models, although total atmospheric burden and lifetime are at the lower end of the published literature. Acetone's new representation in ModelE2.1 also results in more realistic spatial and vertical distributions, which we compare against previous models and field observations. The seasonality of acetone-related processes was also studied in conjunction with field measurements, and these comparisons show promising agreement but also shortcomings at high-emission urban locations, where the model's resolution is too coarse to capture the true behavior. Finally, we conduct a variety of sensitivity studies that explore the influence of key parameters on the acetone budget and its global distribution. An impactful finding is that the production of acetone from precursor hydrocarbon oxidation has strong leverage on the overall chemical source, indicating the importance of accurate molar yields. Overall, our implementation is one that corroborates with previous studies and marks a significant improvement in the development of the acetone tracer in GISS ModelE2.1.

Phylogenomics and genetic analysis of solvent-producing Clostridium species.

The genus Clostridium is a large and diverse group within the Bacillota (formerly Firmicutes), whose members can encode useful complex traits such as solvent production, gas-fermentation, and lignocellulose breakdown. We describe 270 genome sequences of solventogenic clostridia from a comprehensive industrial strain collection assembled by Professor David Jones that includes 194 C. beijerinckii, 57 C. saccharobutylicum, 4 C. saccharoperbutylacetonicum, 5 C. butyricum, 7 C. acetobutylicum, and 3 C. tetanomorphum genomes. We report methods, analyses and characterization for phylogeny, key attributes, core biosynthetic genes, secondary metabolites, plasmids, prophage/CRISPR diversity, cellulosomes and quorum sensing for the 6 species. The expanded genomic data described here will facilitate engineering of solvent-producing clostridia as well as non-model microorganisms with innately desirable traits. Sequences could be applied in conventional platform biocatalysts such as yeast or Escherichia coli for enhanced chemical production. Recently, gene sequences from this collection were used to engineer Clostridium autoethanogenum, a gas-fermenting autotrophic acetogen, for continuous acetone or isopropanol production, as well as butanol, butanoic acid, hexanol and hexanoic acid production.

Decoupling acidogenic cascade via bio-electrogenic induced ABE pathway for enhanced n-butanol synthesis in Clostridium acetobutylicum ATCC-824: Bioenergetics and gene expression analysis

This investigation scrutinized the quantitative aspects of biobutanol production in conventional and bioelectrogenic induced ABE fermentation using Clostridium acetobutylicum ATCC-824. The primary objective of the study was to investigate how alterations in the extracellular redox potential (-0.4 V vs. Ag/AgCl (3.5 M KCl)) affect the hetero-fermentation towards the production of acetone, butanol, and ethanol during the bi-phasic fermentation, utilizing different glucose concentrations from 20 g/L − 60 g/L. The study showed significant results with 68.86 % increased butanol titer (6.67 g/L) compared to conventional fermentation (3.95 g/L butanol). Additionally, the acetone production also increased to 2.34 g/L as compared to conventional fermentation (1.96 g/L). Furthermore, gene expression and network analysis showed that various ABE pathway genes were significantly up or down regulated during the bi-phasic fermentation, indicating a difference between the conventional and EF reactors. The external potential influenced the overexpression of genes like pta, crt, bcd, ask, adh (CA_C1574), and hbd (CA_C3375), while simultaneously downregulation of buk gene, suggesting the acidogenic decoupling and transition from cold channel (butyric acid) towards hot channel pathway (directly from acetyl CoA through butyryl-CoA) for improved butanol production. Moreover, the study also revealed that entropy and enthalpy changes played a significant role in butanol production and ABE fermentation. The EF showed more negative free energy (-3.33 × 104 kJ/mol) when compared with conventional fermentation (-2.8 × 104 kJ/mol) suggesting the mechanism to be more spontaneous and viable. Overall, this study provided evidence of metabolic rerouting with non-genetic approach by regulating electron flow, culminating in an impact on the bi-phasic fermentation towards specific metabolites.

Isopropanol production via the thermophilic bioconversion of sugars and syngas using metabolically engineered Moorella thermoacetica

BackgroundIsopropanol (IPA) is a commodity chemical used as a solvent or raw material for polymeric products, such as plastics. Currently, IPA production depends largely on high-CO2-emission petrochemical methods that are not sustainable. Therefore, alternative low-CO2 emission methods are required. IPA bioproduction using biomass or waste gas is a promising method.ResultsMoorella thermoacetica, a thermophilic acetogenic microorganism, was genetically engineered to produce IPA. A metabolic pathway related to acetone reduction was selected, and acetone conversion to IPA was achieved via the heterologous expression of secondary alcohol dehydrogenase (sadh) in the thermophilic bacterium. sadh-expressing strains were combined with acetone-producing strains, to obtain an IPA-producing strain. The strain produced IPA as a major product using hexose and pentose sugars as substrates (81% mol-IPA/mol-sugar). Furthermore, IPA was produced from CO, whereas acetate was an abundant byproduct. Fermentation using syngas containing both CO and H2 resulted in higher IPA production at the specific rate of 0.03 h−1. The supply of reducing power for acetone conversion from the gaseous substrates was examined by supplementing acetone to the culture, and the continuous and rapid conversion of acetone to IPA showed a sufficient supply of NADPH for Sadh.ConclusionsThe successful engineering of M. thermoacetica resulted in high IPA production from sugars. M. thermoacetica metabolism showed a high capacity for acetone conversion to IPA in the gaseous substrates, indicating acetone production as the bottleneck in IPA production for further improving the strain. This study provides a platform for IPA production via the metabolic engineering of thermophilic acetogens.

Influence of acetate concentration on acetone production by a modified Acetobacterium woodii

Global warming is the driving force for developing production processes of chemical compounds based on CO2 reduction technologies. Bacteria can act as biological catalysts that reduce this gaseous substrate in added-value compounds. Acetobacterium woodii is one of the best-performing strains on H2–CO2 blends and naturally produces acetate. Acetone is a raw material deeply used in the chemical industry, and its global demand is increasing. Acetone-butanol-ethanol (ABE) fermentation is the oldest microbial production platform for acetone synthesis from organic substrates, and Clostridium acetobutylicum is the model strain for its production. In various wild-type acetogens and ABE-producing Clostridium species, acetate positively influences the synthesis of reduced products. In this work, a modified A. woodii strain expressing the enzymes of the acetone pathway from C. acetobutylicum was used to convert H2–CO2 streams into acetone. This study aims to assess the impact of acetate on acetone production catalyzed by such a modified A. woodii. Tests were carried out in serum bottles and a continuous stirred tank reactor up to a pressure of 10 bar, in gas-batch or in continuous gassing, providing different gas mixes. Outcomes indicated that acetone synthesis was stimulated when acetate concentration in the medium exceeded the threshold of 100–120 mM. Thus, acetic acid can affect acetone productivity in the modified A. woodii strain. This outcome should be considered in the design of fermentation processes, especially in setting up fermentations with the liquid continuous operative mode.

Advanced purification of isopropanol and acetone from syngas fermentation

AbstractBACKGROUNDIsopropanol and acetone production by syngas fermentation is a promising alternative to conventional fossil carbon‐dependent production. However, this alternative technology has not yet been scaled up to an industrial level owing to the relatively low product concentrations (about 5 wt% in total). This original research aims to develop cost‐effective and energy‐efficient processes for the recovery of isopropanol and acetone from highly dilute fermentation broth (>94 wt% water) for large‐scale production (about 100 ktIPA+AC y−1).RESULTSVacuum distillation and pass‐through distillation enhanced with heat pumps or multi‐effect distillation were efficiently coupled with regular atmospheric distillation and extractive distillation in several innovative intensified downstream processes. Over 99.2% of isopropanol and 100% of acetone were recovered as high‐purity end‐products (>99.8 wt%). Advanced heat pumping (mechanical vapor recompression) and heat integration techniques were implemented to decrease total annual costs (0.109–0.137 USD kgIPA+AC−1), reduce energy requirements (1.348–2.043 kWth h kgIPA+AC−1) and lower CO2 emissions (0.067–0.191 kgCO2 kgIPA+AC−1), resulting in highly competitive recovery processes.CONCLUSIONThe proposed three novel isopropanol and acetone recovery processes from dilute broth significantly contribute to the expansion of sustainable industrial fermentation. Furthermore, this original research is the first one to develop novel pass‐through distillation technology for the complex isopropanol–acetone–water system. All the designed processes are highly economically competitive and environmentally viable. In addition to recovering efficiently both isopropanol and acetone, the designed downstream processes offer the possibility to enhance the fermentation process by recycling all the present microorganisms and reducing fresh‐water requirements. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Microbiological and molecular genetic characterization of Staphylococcus aureus and Staphylococcus pseudintermedius

Coagulase-positive staphylococci are an important infectious agentcausing numerous infections in animals. Staphylococcus aureus andStaphylococcus pseudintermedius share a number of similar cultural andbiochemical characteristics, which makes their differentiation difficult.Since these species have different zoonotic potential, it is advisable todevelop rapid and specific schemes for species differentiation of pathogens.We have studied the cultural and biochemical characteristics ofStaphylococcus spp. isolated from dogs, cats and cows. In total, 103halophilic coccal cultures were isolated from companion animals and45 from cows, of which 55 and 30 cultures were coagulase-positivestaphylococci, respectively. The reactions that can be used to differentiateS. pseudintermedius and S. aureus were studied. Growth inhibition zonesaround the disk with polymyxin B antibiotic for S. pseudintermediuswere statistically higher (p<0.001) than for S. aureus. The determinationof acetone production to differentiate between these pathogens hasless specificity, as 30% of S. pseudintermedius showed a false-positivereaction. The belonging of two isolates to the species Staphylococcuspseudintermedius was confirmed by MALDI-TOF.The virulence of staphylococci is due to the presence of genesthat regulate the synthesis of various pathogenicity factors and causeantibiotic resistance. Molecular genetic methods can detect the presenceof gene specificity and help to assess the risk of a particular strain causinginfection. Using classical and real-time PCR, the mecA gene was detectedin 8 S. aureus strains and 1 S. pseudintermedius strain that showedphenotypic resistance to methicillin. The pathogenicity genes lukF andsiet were present in 100%, and the lukS gene in 90% of the studiedStaphylococcus pseudintermedius.The study highlights a number of aspects of the diagnosis anddifferentiation of coagulase-positive staphylococci. The possibility ofusing the Neonatal FAST well D-ONE microculture system for use inveterinary laboratories was also studied. The data obtained can be usedto develop methodological approaches to the identification of pathogenicstaphylococci using a combination of different methods. Key words: S. pseudintermedius, resistance to methicillin,pathogenicity genes, MALDI-TOF MS.

New insight of solvent-replacement-induced damage to pores of cement stone by comparison with 1H NMR relaxometry, mercury intrusion porosimetry, and nitrogen adsorption

The consensus on the damage to pore structure of cement-based materials caused by solvent-displacement-drying method has yet not been achieved. This work explored the effect of replacing pore water with ethanol, methanol, isopropanol, cyclohexane and acetone on the pore parameters of hardened white cement paste by means of low field NMR, mercury intrusion porosimetry and nitrogen adsorption techniques, with direct-drying (oven-drying and vacuum-drying) as the control. The results show that the degree of damage to the pore structure after secondary-solvent-replacement is close to that of direct- drying in terms of porosity, total pore area, characteristic pore size and pore size distribution. The difference of pore parameters of samples dried by different solvent-displacement is caused by the physical properties of solvents and the reaction with hydration products. Furthermore, thermal analysis results have confirmed the reaction between acetone and hydration products to generate a dark brown substance. If the possible chemical reaction between organic solvents and hydration products is not considered, the pore structure of cement stone can be well protected by replacing pore water with methanol.

Four functional profiles for fibre and mucin metabolism in the human gut microbiome

BackgroundWith the emergence of metagenomic data, multiple links between the gut microbiome and the host health have been shown. Deciphering these complex interactions require evolved analysis methods focusing on the microbial ecosystem functions. Despite the fact that host or diet-derived fibres are the most abundant nutrients available in the gut, the presence of distinct functional traits regarding fibre and mucin hydrolysis, fermentation and hydrogenotrophic processes has never been investigated.ResultsAfter manually selecting 91 KEGG orthologies and 33 glycoside hydrolases further aggregated in 101 functional descriptors representative of fibre and mucin degradation pathways in the gut microbiome, we used nonnegative matrix factorization to mine metagenomic datasets. Four distinct metabolic profiles were further identified on a training set of 1153 samples, thoroughly validated on a large database of 2571 unseen samples from 5 external metagenomic cohorts and confirmed with metatranscriptomic data. Profiles 1 and 2 are the main contributors to the fibre-degradation-related metagenome: they present contrasted involvement in fibre degradation and sugar metabolism and are differentially linked to dysbiosis, metabolic disease and inflammation. Profile 1 takes over Profile 2 in healthy samples, and unbalance of these profiles characterize dysbiotic samples. Furthermore, high fibre diet favours a healthy balance between profiles 1 and profile 2. Profile 3 takes over profile 2 during Crohn’s disease, inducing functional reorientations towards unusual metabolism such as fucose and H2S degradation or propionate, acetone and butanediol production. Profile 4 gathers under-represented functions, like methanogenesis. Two taxonomic makes up of the profiles were investigated, using either the covariation of 203 prevalent genomes or metagenomic species, both providing consistent results in line with their functional characteristics. This taxonomic characterization showed that profiles 1 and 2 were respectively mainly composed of bacteria from the phyla Bacteroidetes and Firmicutes while profile 3 is representative of Proteobacteria and profile 4 of methanogens.ConclusionsIntegrating anaerobic microbiology knowledge with statistical learning can narrow down the metagenomic analysis to investigate functional profiles. Applying this approach to fibre degradation in the gut ended with 4 distinct functional profiles that can be easily monitored as markers of diet, dysbiosis, inflammation and disease.6PP5aGzbMER7d2AAtHiJDfVideo

Site-directed mutagenesis enhances the activity of benzylidene acetone synthase of polyketide synthase from Polygonum cuspidatum

Polygonum cuspidatum polyketide synthase 1 (PcPKS1) has the catalytic activity of chalcone synthase (CHS) and benzylidene acetone synthase (BAS), which can catalyze the production of polyketides naringenin chalcone and benzylidene acetone, and then catalyze the synthesis of flavonoids or benzylidene acetone. In this study, three amino acid sites (Thr133, Ser134, Ser33) that may affect the function of PcPKS1 were identified by analyzing the sequences of PcPKS1, the BAS from Rheum palmatum and the CHS from Arabidopsis thaliana, as well as the conformation of the catalytic site of the enzyme. Molecular modification of PcPKS1 was carried out by site-directed mutagenesis, and two mutants were successfully obtained. The in vitro enzymatic reactions were carried out, and the differences in activity were detected by high performance liquid chromatography (HPLC). Finally, mutants T133LS134A and S339V with bifunctional activity were obtained. In addition to bifunctional activities of BAS and CHS, the modified PcPKS1 had much higher BAS activity than that of the wild type PcPKS1 under the conditions of pH 7.0 and pH 9.0, respectively. It provides a theoretical basis for future use of PcPKS1 in genetic engineering to regulate the biosynthesis of flavonoids and raspberry ketones.

Techno-economic and energetic assessment of an innovative energy-saving separation process for electronic-grade acetone purification

With the impact of covid-19 and geopolitical instability, the price of energy and medical-related chemicals are increased. Acetone is used as the main material for the synthesis of important disinfectant isopropanol, which the price is influenced by covid-19 impact. The research on acetone purification, especially on the acetone refining section in the cumene hydroperoxide process is of great importance, which is high in energy cost but the most popular method for acetone production. This paper provided novel energy-saving acetone purification processes with heat integration, heat recovery, and molecular sieve adsorption, and made comprehensive research of different schemes applications with optimization. A modified TAC calculation model for adsorption units is first proposed in this paper, which includes the calculation of adsorption unit cost, molecular sieve loss, and molecular sieve regeneration cost. CO2 emission and thermodynamic efficiency of all the processes are compared. A semi-quantitative analysis is used to compare the relative industrial versatility and process controllability. The results show that the combination of adsorption and heat integration achieves a decrease of 27.75% in energy consumption, 15.30% in TAC, 7.09% in CO2 emission, and a 22.62% relative increase in thermodynamic efficiency.

Techno-economic analysis of a microalgae-based biorefinery network for biofuels and value-added products

Biorefineries have the potential to become economically competitive through the exploitation of all biomass conversion scenarios. This study presents a technoeconomic assessment of a microalgal biorefinery for the integrated production of biodiesel, biobutanol, and co-products acetone, ethanol, and glycerol. Pre-treatment stages include acid hydrolysis (AH) and solvent extraction (SX), in two different processing networks (Configuration 1: AH followed by SX; Configuration 2: SX followed by AH). The lowest Minimum Fuel Selling Price (MFSP) was attained by Configuration 1 ($2.11/kg total biofuel), which was 75 % and 11 % lower than the single-fuel biobutanol and biodiesel conversion scenarios, respectively. Sensitivity analysis showed that the feedstock costs, inlet rate, and solvent usage (SX), have the greatest effect on the MFSP. Results also showed that the selling price of biobutanol is highly sensitive to fluctuations in biodiesel prices, which may have implications on a growing fuels market with unpredictable supply and demand.

The Computational Acid-Base Chemistry of Hepatic Ketoacidosis.

Opposing evidence exists for the source of the hydrogen ions (H+) during ketoacidosis. Organic and computational chemistry using dissociation constants and alpha equations for all pertinent ionizable metabolites were used to (1) document the atomic changes in the chemical reactions of ketogenesis and ketolysis and (2) identify the sources and quantify added fractional (~) H+ exchange (~H+e). All computations were performed for pH conditions spanning from 6.0 to 7.6. Summation of the ~H+e for given pH conditions for all substrates and products of each reaction of ketogenesis and ketolysis resulted in net reaction and pathway ~H+e coefficients, where negative revealed ~H+ release and positive revealed ~H+ uptake. Results revealed that for the liver (pH = 7.0), the net ~H+e for the reactions of ketogenesis ending in each of acetoacetate (AcAc), β-hydroxybutyrate (β-HB), and acetone were -0.9990, 0.0026, and 0.0000, respectively. During ketogenesis, ~H+ release was only evident for HMG CoA production, which is caused by hydrolysis and not ~H+ dissociation. Nevertheless, there is a net ~H+ release during ketogenesis, though this diminishes with greater proportionality of acetone production. For reactions of ketolysis in muscle (pH = 7.1) and brain (pH = 7.2), net ~H+ coefficients for β-HB and AcAc oxidation were -0.9649 and 0.0363 (muscle), and -0.9719 and 0.0291 (brain), respectively. The larger ~H+ release values for β-HB oxidation result from covalent ~H+ release during the oxidation-reduction. For combined ketogenesis and ketolysis, which would be the metabolic condition in vivo, the net ~H+ coefficient depends once again on the proportionality of the final ketone body product. For ketone body production in the liver, transference to blood, and oxidation in the brain and muscle for a ratio of 0.6:0.2:0.2 for β-HB:AcAc:acetone, the net ~H+e coefficients for liver ketogenesis, blood transfer, brain ketolysis, and net total (ketosis) equate to -0.1983, -0.0003, -0.2872, and -0.4858, respectively. The traditional theory of ketone bodies being metabolic acids causing systemic acidosis is incorrect. Summation of ketogenesis and ketolysis yield H+ coefficients that differ depending on the proportionality of ketone body production, though, in general, there is a small net H+ release during ketosis. Products formed during ketogenesis (HMG-CoA, acetoacetate, β-hydroxybutyrate) are created as negatively charged bases, not acids, and the final ketone body, acetone, does not have pH-dependent ionizable groups. Proton release or uptake during ketogenesis and ketolysis are predominantly caused by covalent modification, not acid dissociation/association. Ketosis (ketogenesis and ketolysis) results in a net fractional H+ release. The extent of this release is dependent on the final proportionality between acetoacetate, β-hydroxybutyrate, and acetone.

Toluene and 2-propanol mixture oxidation over Mn2O3 catalysts: Study of inhibition/promotion effects by in-situ DRIFTS

Three Mn2O3 catalysts were synthetized by different methods, characterized and tested in toluene and 2-propanol (iPrOH) oxidation in single and binary component mixture. In single VOC media, the catalytic activity was strongly influenced by the specific surface area, low-temperature reducibility and active surface-oxygen species. In the binary VOCs mixture oxidation, light-off curves were shifted to lower temperatures, suggesting a promoting effect on the catalytic activity for toluene and iPrOH oxidation. The acetone production in binary mixture was also shifted to lower temperatures. The obtained results were rationalized based on the different polarity of the VOCs, the available adsorbed oxygen and the exothermic character of the VOCs combustion. These promoting effects were pointed out by in-situ DRIFTS measurements, in which the pre-adsorption of any of these two VOCs affected the adsorption/reaction of the other. For the first time, in-situ DRIFTS has been applied to elucidate the reaction mechanisms of the oxidation of toluene/2-propanol mixture on Mn2O3, which allowed to correlate the surface phenomena and the catalytic performance.

Preparation by two simple methods and characterization of Ni3N and use in the hydrogenation of isopropanol

The catalytic dehydrogenation of isopropanol is an important area of the catalytic process to produce fine chemicals and has important applications in heat pumps, fuel cells, and acetone production. Thereby, the catalytic liquid-phase dehydrogenation of isopropanol has gained attention over the last decades and has used a large variety of homogeneous and heterogeneous catalysts. In this paper, nickel nitride (Ni3N) nanoparticles, having a cubic structure, were successfully synthesized in simple and efficient methods either from nickel oxide or from nickel complex. The morphological and structural analyses of the obtained nanoparticles were performed by using powder X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). At room temperature and under atmospheric pressure, the dehydrogenation test of isopropanol, using nickel nitride as a catalyst, revealed very high activity and better Hydrogen production.

Exploration of separate hydrolysis and fermentation and simultaneous saccharification and co-fermentation for acetone, butanol, and ethanol production from combined diluted acid with laccase pretreated Puerariae Slag in Clostridium beijerinckii ART44

In this study, an efficient pretreatment technology was developed for the bioconversion of puerariae slag (PS) into biobutanol. To accelerate the enzymatic saccharification of PS, the method of dilute acid combined with laccase pretreatment (DALP) was performed. With this effort, the highest concentration of reducing sugar was 48.96 ± 1.69 g/L after enzymatic hydrolysis of the whole slurry pretreatment under the optimal condition. Subsequently, the highest butanol productivity (0.15 g/L/h) was obtained by the simultaneous saccharification and co-fermentation (SSCF), which was 114.29% higher than that of the separate hydrolysis and fermentation (SHF). Furthermore, the microstructural changes of PS after different pretreatment were initially investigated by FT-IR, and we found that the DALP method resulted in more severe damage during the pretreatment process, which could improve the efficiency of enzymatic saccharification. This study suggests that the DALP is an attainable and efficient pretreatment method for production of butanol in the SSCF process.