Short-chain Alcohols Research Articles

Influences of short-chain alcohols, urea and temperature on aggregation behaviour of tetradecyltrimethylammonium bromide and antidiabetic drug mixture

In this investigation, the supramolecular interaction between a surfactant- tetradecyltrimethylammonium bromide (TTAB) and an antidiabetic drug metformin hydrochloride (MNH) was studied in the presence of some additives (alcohols/urea). The conductometric analysis as a function of surfactant concentration was used to assess the critical micelle concentration (CMC) of TTAB + MNH mixed system. The effect of a gradual change of temperature on CMC within a certain range (298.15–318.15 K) was monitored to assess the thermodynamic nature of micellisation process. In addition, estimation of thermodynamic parameters (, , and ) and the determination of the degree of counter ion binding (β) give insight into the relative viability of a micellisation process. The values of were negative in all the mixed solvents studied and this was dependent on the chain length of the used alcohols. The thermodynamic parameters of transfer for shifting the micelles from aq. medium to aq. alcohols media and enthalpy-entropy compensation were also computed, compared with literature values and discussed with appropriate reasoning. Several supramolecular forces, including H-bonds, dipole–dipole, ion-dipole, hydrophobic, and electrostatic interactions, were recommended for the aggregation of the TTAB + MNH system.

Utilizing Alcohol for Alkane Biosynthesis by Introducing a Fatty Alcohol Dehydrogenase.

Alkanes produced by microorganisms are expected to be an alternative to fossil fuels as an energy source. Microbial synthesis of alkanes involves the formation of fatty aldehydes via fatty acyl coenzyme A (acyl-CoA) intermediates derived from fatty acid metabolism, followed by aldehyde decarbonylation to generate alkanes. Advancements in metabolic engineering have enabled the construction of such pathways in various microorganisms, including Escherichia coli. However, endogenous aldehyde reductases in the host microorganisms are highly active in converting fatty aldehydes to fatty alcohols, limiting the substrate pool for alkane production. To reuse the alcohol by-product, a screening of fatty alcohol-assimilating microorganisms was conducted, and a bacterial strain, Pantoea sp. strain 7-4, was found to convert 1-tetradecanol to tetradecanal. From this strain, an alcohol dehydrogenase, PsADH, was purified and found to be involved in 1-tetradecanol-oxidizing reaction. Subsequent heterologous expression of the PsADH gene in E. coli was conducted, and recombinant PsADH was purified for a series of biochemical characterizations, including cofactors, optimal reaction conditions, and kinetic parameters. Furthermore, direct alkane production from alcohol was achieved in E. coli by coexpressing PsADH with a cyanobacterial aldehyde-deformylating oxygenase and a reducing system, including ferredoxin and ferredoxin reductase, from Nostoc punctiforme PCC73102. The alcohol-aldehyde-alkane synthetic route established in this study will provide a new approach to utilizing fatty alcohols for the production of alkane biofuel. IMPORTANCE Alcohol dehydrogenases are a group of enzymes found in many organisms. Unfortunately, studies on these enzymes mainly focus on their activities toward short-chain alcohols. In this study, we discovered an alcohol dehydrogenase, PsADH, from the bacterium Pantoea sp. 7-4, which can oxidize 1-tetradecanol to tetradecanal. The medium-chain aldehyde products generated by this enzyme can serve as the substrate of aldehyde-deformylating oxygenase to produce alkanes. The enzyme found in this study can be applied to the biosynthetic pathway involving the formation of medium-chain aldehydes to produce alkanes and other valuable compounds.

A New Molecular Insight in Effects of Alcohol Co-Solvents on Miscibility of Anhydrous Ethanol/Diesel Blends

Abstract Sustainable policy leads to partially replace fossil diesel by bio-fuels and ethanol/diesel blends. The major challenge is how to enhance miscibility of ethanol with diesel. Molecular dynamics simulation was applied to study the effects of alcohol co-solvents on miscibility of ethanol with diesel. The 1-heptanol, 1-decanol, n-butanol, and butanol isomers were selected as co-solvents. The diesel model was constructed to quantitatively characterize miscibility and obtain interaction of ethanol and diesel. The solubility parameters, structural feature, and energy properties were analyzed. The results showed that long-chain alcohol co-solvents contributed to miscibility of blends. The aromatics had more effects on miscibility than linear alkanes and cycloalkanes. Radial distribution function results showed that straight-chain alcohols or high linearity co-solvents promoted miscibility of ethanol than branched alcohols. The energy analysis revealed that the hydrogen bonding and van der Waals interaction were the main driving forces to improve miscibility, while polarization interaction had no major contribution. The hydrogen bonding dominated for short-chain alcohols, while van der Waals interaction was vital for long-chain alcohols. The coordination of hydrogen bonding and van der Waals energy in dynamic equilibrium led to the optimal miscibility.

Effect of short-chain alcohols on the physicochemical properties of d-phenothrin emulsions and their insecticidal activity against Aedes aegypti

Oil-in-water (o/w) emulsion is utilized as an insecticide delivery system for mosquito control. However, evaporation inhibition adjuvant is needed to prevent fog drift, inhibit release of insecticidal actives and prolong suspension time. In the current study, we evaluated the effect of different short-chain alcohols, namely, propylene glycol, 1,3-propanediol, glycerol and crude glycerol, as adjuvants on the physicochemical properties of d-phenothrin o/w emulsion system. The bioactivity of optimized formulations containing 20 wt% glycerol (D1), 20 wt% propylene glycol (D2) and without added alcohol (negative control) were tested against larvae, pupae and adult Aedes aegypti (Ae. aegypti). It was found that propylene glycol produced smaller droplets at lower concentrations but poor long-term stability at higher concentrations, whereas glycerol had an appreciable effect on initial droplet size and stability with increasing concentration. According to the dose-response bioassays and room size chamber testing, the highest larvicidal, pupicidal and adulticidal activities were observed with D2, followed by D1 and negative control. Overall, the above study demonstrated improved emulsion stabilities and potency against Ae. aegypti larvae, pupae and adults using glycerol as adjuvant for effective mosquito control.

Improved Catalytic Performance of Lipase Eversa® Transform 2.0 via Immobilization for the Sustainable Production of Flavor Esters—Adsorption Process and Environmental Assessment Studies

The aim of this study was to produce several flavor esters via esterification of octanoic acid with different commercial short-chain alcohols (methanol, propanol, isoamyl alcohol, hexanol and benzyl alcohol) and fusel oil in solvent-free systems. Lipase Eversa® Transform 2.0 immobilized via mechanism of interfacial activation on poly(styrenene-divinylbenzene) (PSty-DVB) beads was used as heterogeneous biocatalyst and its catalytic performance was compared with that of the soluble lipase. The heterogeneous biocatalyst was prepared by employing 5 mmol·L−1 buffer sodium acetate at pH 5.0 and 25 °C using an initial protein loading of 40 mg·g−1. The maximum amount of immobilized protein reached was 31 mg·g−1, corresponding to an immobilization yield of 80%. Mass transfer studies demonstrated that the lipase was preferentially adsorbed inside the pores of the support, which was confirmed by scanning electron microscopy analysis. Lipase immobilization can be described by a pseudo-first-order kinetic model via a physisorption process. When used as biocatalysts of the target reactions, the highest conversion percentage (between 65% and 85% of acid conversion after 60–90 min of reaction) values were achieved for esterification reactions catalyzed by immobilized lipase. Reusability tests revealed high retention of the original activity of the immobilized lipase after six successive batch reactions using isoamyl alcohol (47%) and fusel oil (72%). The proposed reaction systems can be considered green processes (EcoScale score above 80), with exception of methanol medium, classified as an acceptable green process (EcoScale score of 68). These results show that the heterogeneous biocatalyst prepared can be an economic and sustainable option for flavor esters production on an industrial scale.

Biotransformation of Natural Compounds by Free and Immobilized Fungal Laccase using Mediator Combinations in the LMS Reaction Model

The ternary systems constructed on the basis of isotropic properties of various compositions of a hydrocarbon and a short chain alcohol in a low water content were used to carry out the oxidation of Mastic oil, d-limonene and α-Pinene at 30 °C using fungal laccase from Trametes versicolor in the presence of different concentrations and combinations of three mediators ,2,2'-azino-bis 3-methylbenzothiazoline-6-sulfonic acid(ABTS), 1-hydroxybenzotriazole (HBT) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in Laccase Mediator System (LMS) model . The biotransformation was conducted with the use of either free or immobilized laccase on organogels prepared by introducing appropriate amounts of Dioctyl Sulfosuccinate (AOT) microemulsions containing laccase to a second solution of polymer Hydroxy Propyl Methyl Cellulose (HPMC) . The main oxidation product of α-pinene was verbenone and verbenol, but low amounts of α-pinene oxide was also detected. Similarly, d-limonene was oxidized to limonene epoxide, while mastic oil was oxidized to α-pinene oxide, limonene epoxide, verbenol, verbenone . In all cases, some of the reaction products remained unidentified. The amounts of unidentified products were rather high especially in the case of d-limonene and crude mastic oil. Mediator Combinations with HBT in different ratio were used for further transformation optimization of the three natural compounds in the ternary systems. Ascorbic and Gallic acids in 40mM concentration also were used in combination with HBT to transform the natural compounds. All combinations revealed different level of oxidation and only one combination of Gallic acid and HBT was unable to oxidize any of three compounds. The natural compounds oxidation rate correlated with the mediator concentration in the reaction mixture, and clear synergetic effect were found when two mediators were present, 10mM ABTS and 80mM HBT , while the best triple combination was 10mM ABTS: 40mM HBT: 40mM TEMPO .

Optimization and analysis of bioenergy production using machine learning modeling: Multi-layer perceptron, Gaussian processes regression, K-nearest neighbors, and Artificial neural network models

Since fossil fuels are slowly depleting, bio and renewable energies are now given more attention. The main purpose of this research is to investigate and optimize the influencing parameters of bioenergy production through transesterification process. The application of artificial intelligence (AI) in bioenergy production studies has become increasingly popular due to its capability of interpreting nonlinear relationships between inputs and outputs for complex systems. Here, after conducting library studies and carefully reviewing the existing methods, the multi-layer perceptron (MLP), K-nearest neighbors (KNN), Artificial neural network (ANN), and Gaussian processes regression (GPR) models were selected for simulation and prediction of the efficiency of fatty acid methyl ester (FAME) production. The main effective transesterification parameters on production of biodiesel including the temperature of reaction (°C), catalyst mass to oil mass ratio (wt.%), and the molar ratio of methanol to oil were set as the input variables in all studied models. For reaction between oil and short chain alcohols, wollastonite (a calcium metasilicate, CaSiO3) was utilized as a phase boundary catalyst. By carefully selecting the execution conditions of the algorithms in the model selection phase, all three models reached a result above 0.99 and close to 1 with the square R criterion. Also, the RMSE values for the studied models were 3.95 for MLP, 1.09 for KNN, 0.13 for ANN and 3.60 for GPR models. Therefore, it can be concluded that although the ANN model was to be a better model in process efficiency prediction in terms of error, but all three algorithms had high accuracy because of different generality types. The optimum yield of 97.8% for FAME production was observed at optimum methanol to oil molar ratio, reaction temperature, and catalyst mass to oil mass ratio 65°C, 15, and 9.21 wt%, respectively.

Hildebrand-Assessed Margules (HAM) interaction parameter: Applications to surfactant and polar oil partition

The Hildebrand-Assessed Margules (HAM) method uses Henry's law constant and vapor pressure for pure components from free cheminformatic software to obtain the interaction parameter of a component “i” with water (Aiw) and its molar volume (Vmi). Inspired by the concept of the solubility parameter of Hildebrand (δi), where (Aiw/Vmi)^0.5 = (δi-δw), HAM makes a simple assessment of the binary interaction parameter Aij= (Aiw/Vmi)^0.5 - (Ajw/Vmi)^0.5. The Aij predictions from this relatively simple expression were compared to literature Aij data obtained from activity coefficients at infinite dilution. The performance of the HAM framework was compared to other predictive models, UNIFAC, MOSCED, COSMO-RS, HSP and the original Hildebrand model. The HAM method overpredicted Aij (>1Aij unit) in systems where the solvent was an acid or a base that could dissociate in the presence of water. However, for most systems (small polar molecules, short chain alcohols, medium chain alcohols, aromatics and alkanes), the Aij values were predicted within 1 Aij unit and commonly within 0.5 Aij units. A systemic underprediction of Aij was observed when the HAM-predicted log P was compared to predictions from the ACD/Labs software, which required the introduction of a correction term. The corrected HAM method reproduced the partition coefficient of surfactant and polar molecules with an RMSE of 1.05 (logK units) and an NRMSE of 15%, comparable to other models that require more inputs and resources. Beyond offering a simple path to predict activity coefficients, the simplicity of the HAM approach illustrates the connection between single-component properties and how these properties influence interaction parameters in mixtures.

Phase behaviors, properties and potential application of temperature-responsive microemulsions based on tropine ionic liquids

Compared with traditional microemulsion, stimulating stimulus-responsive microemulsion is more challenging to achieve. A temperature-responsive microemulsion was formulated and optimized by using the mixture of a series of tropine-based ionic liquids (TILs) and water as a polar phase, different aliphatic oils as a nonpolar phase, and an optimal mixture of nonionic surfactant Triton X-100 (TX-100) and different short-chain aliphatic alcohols as a cosurfactant. The results revealed that cyclohexane (as the nonpolar phase) had the better ability to combine with TX-100/1-octanol (mass ratio of 7:3) to form the TILs-based microemulsion, and that the range of monophasic region increased with the length of alkyl chain attached to the TILs cation group. The classic oil-in-water (O/W), liquid crystal (L), mixture of liquid crystal and bicontinuous (B.C.), B.C. and inverse water-in-oil (W/O) subregions were clarified by the conductivity method and rheological measurements. Adding the TILs helps the microemulsion form. The microemulsion was temperature-responsive, and with the increase of mass ratio m(TILs to H2O) and the side chain length of TILs, the sensitivity of the microemulsion to temperature decreased. Dynamic light scattering and electron electron microscopy revealed the formation of spherical droplets of approximately 2 to 5 nm in size in the W/O subregions with droplet size increasing with the increase of molar ratio R (TILs + H2O to mixed surfactant), mass ratio m(TILs to H2O) and TILs side chain length. Measurements of polarity and particle size showed that the TILs were dissolved into the core of the aqueous phase and, along with water, became the polar phase of the microemulsion. The microemulsion formation was driven by the hydrogen bonding between TX-100 and the polar phase. The TILs-based microemulsion could be used to prepare nanoparticles of silica with dimensions of 50–73 nm. This comprehensive study provides useful information for the development of analogous TILs-based microemulsions, and these temperature-responsive microemulsions have promising applications simply by treating the mass ratio m(TILs to H2O) and side chain length of TILs.

Volatility criteria and physicochemical properties of the promising dimethyl carbonate-gasoline blends

Increased need for energy resources, as well as the urgent need to improve the air quality, have prompted further research to meet these challenges. Great efforts have been directed to reducing the impact of exhaust emissions. In literature, the effect of blending dimethyl carbonate (DMC) into fuel on engine performance and exhaust emissions has been investigated, and the obtained results were promising in decreasing exhaust emissions. In the present work, the effect of blending DMC into gasoline on the physicochemical properties was studied. Six fuel blends were prepared by blending base gasoline (G) with (0%, 2%, 4%, 6%, 8%, and 10%) of DMC. The volatility characteristics of the fuel blends were studied, such as the distillation curve, vapor pressure, and driveability index. The octane rating and the physicochemical properties of the fuel blends were also studied. The results of the study showed interesting findings that encourage refineries to be interested in this promising fuel additive. The results showed that the addition of DMC to gasoline has a very slight effect on the volatility of gasoline, unlike other oxygenated additives like short chain alcohols which cause a significant increase in the fuel volatility. The addition of DMC to gasoline causes an insignificant increase in the vapor pressure as the addition of 10% of DMC increases the vapor pressure by 2 kPa while it does not affect the values of T10, T50, and T90, which are the most important parameters of the distillation curve. The results also showed that its addition causes a remarkable increase in the octane rating. The RON has increased for the G-10DMC blend by about 5 points making the DMC a promising octane booster.

(Digital Presentation) The Oxidation Behavior of Model Molecules for Electrolysis of Polymer Materials

Most of the plastic recycling is thermal recycling by incineration. As a matter of course, thermal recycling is not a sustainable recycling method for plastic material. Material recycling is being carried out in which some used plastics are molded and reused.[1] However, material recycling has problems that cannot recover the monomer and separate the pigments and dyes. These problems degrade the quality of recycling plastics. Therefore, we focused on the depolymerization and re-polymerization between polymers and monomers by electrolysis in order to develop a new recycling method without degrading the quality of the plastics.However, since polymers are generally insulators, even if they are electrolyzed, the number of reports is small, and the decomposition behavior is unknown. [2, 3] In this study, to obtain basic information for the electrolysis of polymers, a monovalent alcohol molecule bonded to the terminal or side chain and a divalent alcohol molecule bonded to both ends are used as the model molecule, and their electrochemical behavior was investigated. In addition, electrolysis of PVA and PEG, which have similar structures to alcohol molecules, was conducted as the first step of depolymerization into monomers.The electrochemical cell in this study was composed of Pt working and counter electrodes, Ag/AgCl reference electrode, and 0.1 M HClO4. Cyclic voltammetry (CV) was conducted at room temperature in an inert atmosphere, and the scanning speed was 10 mV s-1. The decomposition behavior of model molecules was studied by adding 1 mL each of 1 to 10 carbon atoms (linear) of primary alcohol and 3, 5, 7, 9 carbon atoms (linear) of a secondary alcohol, ethylene glycol, PVA, and PEG into the electrolyte.In the case of primary alcohols, the oxidation currents decreased with the longer chain length. The relatively short carbon chain alcohols composed of 1 to 4 carbon atoms showed first-step oxidation between 1.0 V and 1.2 V on the anodic scan and second-step oxidation near 0.8 V on the cathodic scan. In the alcohol with 5 to 8 carbon atoms, the first-step oxidation peak was shifted to the high potential region with the increasing length of the carbon chain. Here, the potential of the second-step oxidation peak was the same as the short carbon chain alcohols. In contrast, the alcohol with 9 or 10 carbon atoms hardly oxidizes and may be adsorbed on the Pt electrode surface. In Addition, the oxidation behavior of ethylene glycol was similar to that of primary alcohols with short chain lengths such as methanol and ethanol.The trend of oxidation behavior in the secondary alcohols was almost agreed with the primary alcohols. In the cases of 3-pentanol and 4-heptanol, the oxidation current at the high potential region and the reduction current at the low potential region were observed at the boundary of 0.8V. Currently, this electrochemical behavior is thought that these alcohols may change reversibly. The oxidation current of 3-pentanol and 4-heptanol was slightly higher than the reduction current. Thus, the oxidation reaction of secondary alcohols appeared to be slightly predominant. The above results indicated that the longer the chain length of primary and secondary alcohols was hard to oxidize. The changing position of the functional group influenced oxidation. In particular, those attached to the ends were more easily oxidized.Both PVA and PEG were oxidized, but PEG was found to be more oxidized. Based on the results for the alcohol molecule, the position of the functional group on the main chain is thought to be a factor.Electrochemical measurements were performed on linear primary alcohols with 1 to 10 carbon atoms, secondary alcohols with 3, 5, 7, and 9 carbon atoms, and ethylene glycol. The trend of oxidation behavior was that the oxidation currents decreased with the longer chain length. Obtained results indicated that oxidation reaction in the case of the functional group attaching to the end of the carbon chain progressed easier than others. PVA and PEG, similar in structure to the alcohol molecule, showed that PEG and PVA were oxidized, but PEG was more oxidized.[1] T. Kamo, Science of the Field, 1, (2021) 28-44.[2] O. R. Luca et al. Molecules, 25 (2020) 1-9.[3] T. Jiang et al. Solar Energy Materials & Solar Cells, 204 (2020) 1-10.

Effect of Inoculation with Lentilactobacillus buchneri and Lacticaseibacillus paracasei on the Maize Silage Volatilome: The Advantages of Advanced 2D-Chromatographic Fingerprinting Approaches.

In this study, the complex volatilome of maize silage samples conserved for 229 d, inoculated with Lentilactobacillus buchneri (Lbuc) and Lacticaseibacillus paracasei (Lpar), is explored by means of advanced fingerprinting methodologies based on comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry. The combined untargeted and targeted (UT) fingerprinting strategy covers 452 features, 269 of which were putatively identified and assigned within their characteristic classes. The high amounts of short-chain free fatty acids and alcohols were produced by fermentation and led to a large number of esters. The impact of Lbuc fermentation was not clearly distinguishable from the control samples; however, Lpar had a strong and distinctive signature that was dominated by propionic acid and 1-propanol characteristic volatiles. The approach provides a better understanding of silage stabilization mechanisms against the degradative action of yeasts and molds during the exposure of silage to air.

The potential of caproate (hexanoate) production using Clostridium kluyveri syntrophic cocultures with Clostridium acetobutylicum or Clostridium saccharolyticum.

Caproate (hexanoate) and other medium-chain fatty acids are valuable platform chemicals produced by processes utilizing petroleum or plant oil. Clostridium kluyveri, growing on short chain alcohols (notably ethanol) and carboxylic acids (such as acetate) is noted for its ability to perform chain elongation to produce 4- to 8-carbon carboxylates. C. kluyveri has been studied in monoculture and coculture conditions, which lead to relatively modest carboxylate titers after long fermentation times. To assess the biosynthetic potential of C. kluyveri for caproate production from sugars through coculture fermentations, in the absence of monoculture data in the literature suitable for our coculture experiments, we first explored C. kluyveri monocultures. Some monocultures achieved caproate titers of 150 to over 200 mM in 40–50 h with a production rate of 7.9 mM/h. Based on that data, we then explored two novel, syntrophic coculture partners for producing caproate from sugars: Clostridium acetobutylicum and Clostridium saccharolyticum. Neither species has been cocultured with C. kluyveri before, and both demonstrate promising results. Our experiments of C. kluyveri monocultures and C. kluyveri—C. saccharolyticum cocultures demonstrate exceptionally high caproate titers (145–200 mM), fast production rates (3.25–8.1 mM/h), and short fermentation times (18–45 h). These results represent the most caproate produced by a C. kluyveri coculture in the shortest known fermentation time. We also explored the possibility of heterologous cell fusion between the coculture pairs similar to the results seen previously in our group with C. acetobutylicum and Clostridium ljungdahlii. Fusion events were observed only in the C. acetobutylicum—C. kluyveri coculture pair, and we offer an explanation for the lack of fusion between C. saccharolyticum and C. kluyveri. This work supports the promise of coculture biotechnology for sustainable production of caproate and other platform chemicals.

Dipolar Dispersion Forces in Water-Methanol Mixtures: Enhancement of Water Interactions upon Dilution Drives Self-Association.

Mixtures of short-chain alcohols and water produce anomalous thermodynamic and structural quantities, including molecular segregation into water-rich and alcohol-rich components. Herein, we used molecular dynamics simulations with polarizable models to investigate interactions that could drive the self-association of water molecules in mixtures with methanol (MeOH). As water was diluted with MeOH, significant changes in the distribution of molecules and solvation properties occurred, where water exhibited a clear preference for self-association. When common structural quantities were analyzed, it was found that there was a clear reduction in water-water hydrogen bonding and tetrahedral order (both in terms of typical bulk behavior), contrary to the observed water self-association. However, when dipolar dispersion forces between all molecules as a function of system composition were analyzed, it was found that water-water dipolar interactions became significantly stronger with dilution (6-fold stronger interaction in 75% MeOH compared to 0% MeOH). This was only observed for water, where MeOH-MeOH interactions became weaker as the systems were more dilute in MeOH. These forces result from specific dipole orientations, likely occurring to adopt lower energy configurations (i.e., head-to-tail or antiparallel). For water, this may result from lost other interactions (e.g., hydrogen bonding), leading to more rotational freedom between the dipole moments. These intriguing changes in dipolar interactions, which directly result from structural changes, can therefore explain, in part, the driving force for water self-association in MeOH-water mixtures.

The physicochemical variables and interaction forces for the association of dodecyltrimethylammonium bromide + cefixime trihydrate mixture in aq. short chain alcohols and urea media at different temperatures

To develop the drug formulation and reduce antibiotic resistance in the human body, it is essential to study the drug-surfactant interaction. Herein, the interactions between cefixime trihydrate (CMT) and dodecyltrimethylammonium bromide (DTAB) have been evaluated in different experimental situations at a certain range of temperature (300.55–320.55 K) by means of conductivity measurement. The micellar parameters (CMC, degree of counter ion binding (β)) along with some thermodynamic variables like ΔGm0, ΔHm0, and ΔSm0 etc. were evaluated to investigate the interactions between CMT and DTAB. The plot of specific conductivity against surfactant concentration of the DTAB + CMT mixed system was used to determine critical micelle concentration (CMC). The increase of concentration of alcohols (ethanol and 1-propanol) and urea lowers the counterion binding and enhance the CMC values of the DTAB + CMT system. The increase in temperature causes delayed micellization of DTAB + CMT mixture both in aq. alcoholic and urea media. The alteration of CMC values of the DTAB + CMT implies the existence of interaction between DTAB and CMT in the study environment. The micellization of the DTAB + CMT mixed system in all experimental conditions investigated is spontaneous process that has been confirmed by the achieved negative values of ΔGm0. The values of ΔHm0 and ΔSm0 expose the presence of hydrophobic and electrostatic interactions between CMT and DTAB while the contribution of electrostatic interaction is the main force in aq. EtOH medium.

Industrial light at the end of the iron-containing (group III) alcohol dehydrogenase tunnel.

There are three prominent alcohol dehydrogenases superfamilies: short-chain, medium-chain, and iron-containing alcohol dehydrogenases (FeADHs). Many members are valuable catalysts for producing industrially relevant products such as active pharmaceutical intermediates, chiral synthons, biopolymers, biofuels, and secondary metabolites. However, FeADHs are the least explored enzymes among the superfamilies for commercial tenacities. They portray a conserved structure having a "tunnel-like" cofactor and substrate binding site with particular functions, despite representing high sequence diversity. Interestingly, phylogenetic analysis demarcates enzymes catalyzing distinct native substrates where closely related clades convert similar molecules. Further, homologs from various mesophilic and thermophilic microbes have been explored for designing a solvent and temperature-resistant enzyme for industrial purposes. The review explores different iron-containing alcohol dehydrogenases potential engineering of the enzymes and substrates helpful in manufacturing commercial products.

Short-Chained Alcohols Make Membrane Surfaces Conducive for Melittin Action: Implication for the Physiological Role of Alcohols in Cells.

Alcohols are a part of cellular metabolism, but their physiological roles are not well understood. We investigated the effects of short-chain alcohols on Daphnia pulex and model membranes mimicking the lipid composition of eukaryotic inner mitochondrial membranes. We also studied the synergistic effects of alcohols with the bee venom membrane-active peptide, melittin, which is structurally similar to endogenous membrane-active peptides. The alcohols, from ethanol to octanol, gradually decreased the heart rate and the mitochondrial ATP synthesis of daphnia; in contrast, in combination with melittin, which exerted no sizeable effect, they gradually increased both the heart rate and the ATP synthesis. Lipid packing and the order parameter of oriented films, monitored by EPR spectroscopy of the spin-labeled probe 5-doxylstrearic acid, revealed gradual alcohol-assisted bilayer to non-bilayer transitions in the presence of melittin; further, while the alcohols decreased, in combination with melittin they increased the order parameter of the film, which is attributed to the alcohol-facilitated association of melittin with the membrane. A 1H-NMR spectroscopy of the liposomes confirmed the enhanced induction of a non-bilayer lipid phase that formed around the melittin, without the permeabilization of the liposomal membrane. Our data suggest that short-chain alcohols, in combination with endogenous peptides, regulate protein functions via modulating the lipid polymorphism of membranes.

Integration of morphological, physiological and multi-omics analysis reveals a comprehensive mechanism for cuticular wax during development of greasiness in postharvest apples

Skin greasiness is a common postharvest disorder of apple (Malus × domestica). However, the molecular mechanism of skin greasiness is unclear. In this study, fruits of ‘Golden Delicious’ (GD), ‘Granny Smith’, and ‘Fuji’ with distinct characteristics of greasiness were used for greasiness scoring, wax morphology, wax metabolite, and RNA-seq analyses. Additionally, GD fruit were treated with 1-methylcyclopropene (1-MCP), which repressed greasiness. A partial least squares discriminant analysis (PLS-DA) revealed that wax esters were the critical wax fraction for skin greasiness. Among these wax esters, liquid linoleate esters of short-chain alcohols (C4–C6) and farnesol showed increased contents with increasing greasiness. Their concentrations were significantly correlated with greasiness score. To identify the genes encoding key enzymes for the synthesis of liquid linoleate esters, a weighted gene co-expression network analysis was conducted. MdDCR1, encoding an acyltransferase (defective in cuticular ridges, DCR), was selected as a candidate gene. MdDCR1 was significantly upregulated in greasy skin, and significantly suppressed by 1-MCP treatment. MdDCR1 silencing suppressed the accumulation of liquid linoleate esters of short-chain alcohols, including butyl linoleate, pentyl linoleate, and hexyl linoleate, in GD skin. These results provide insights into the molecular mechanisms of cuticular wax metabolism related to skin greasiness in apple. Our results show that transcriptional regulation of MdDCR1, encoding an acyltransferase that catalyzes the biosynthesis of liquid linoleate esters of short-chain alcohols (C4–C6) via an independent side branch of the C18:2 CoA pathway, regulates the formation of greasiness.

Glycerol and Catalysis by Waste/Low-Cost Materials—A Review

The growing global demand for renewable energy sources can be reached using biofuels such as biodiesel, for example. The most used route to produce biodiesel is the transesterification reaction of oils or fats with short-chain alcohols, generating fatty acid esters (biodiesel) and a very important by-product, glycerol (Gly). Gly is widely used in different sectors of the industry, and in order to add value to this by-product, heterogeneous catalysis becomes a relevant tool, whether to transform glycerol into other chemical products of interest or even use it in the production of catalysts. Among the several studies found in the literature, the use of low-cost materials and/or wastes from the most diverse activities to prepare active catalytic materials for the transformation of Gly has been increasingly reported due to its valuable advantages, especially related to the cost of raw materials and environmental aspects. Thus, this brief review article presents the relationship between catalysis, low-cost materials, waste, and glycerol, through different studies that show glycerol being transformed through reactions catalyzed by materials produced from low-cost sources/waste or with the glycerol itself used as a catalyst.

Quantifying local pH changes in carbonate electrolyte during copper-catalysed hbox {CO}_2 electroreduction using in operando^{13}hbox {C} NMR

The electrochemical carbon dioxide reduction on copper attracted considerable attention within the last decade, since Cu is the only elemental transition metal that catalyses the formation of short-chain hydrocarbons and alcohols. Research in this field is mainly focused on understanding the reaction mechanism in terms of adsorbates and intermediates. Furthermore, dynamic changes in the micro-environment of the catalyst, i.e. local pH and hbox {CO}_2 concentration values, play an equivalently important role in the selectivity of product formation. In this study, we present an in operando^{13}hbox {C} nuclear magnetic resonance technique that enables the simultaneous measurement of pH and hbox {CO}_2 concentration in electrode vicinity during electroreduction. The influence of applied potential and buffer capacity of the electrolyte on the formation of formate is demonstrated. Theoretical considerations are confirmed experimentally and the importance of the interplay between catalyst and electrolyte is emphasised.