High Ethanol Research Articles

Polyamide thin-film composite membranes with enhanced interfacial stability for durable organic solvent nanofiltration

Polyamide thin-film composite (TFC) membranes present a promising option for organic solvent nanofiltration (OSN) due to their superior advantages in facile fabrication and high separation efficiency. However, existing TFC-based OSN membranes are heavily limited by their weak interfacial stability in organic solvents, because many solvent-resistant porous supports are hydrophobic and have poor interfacial compatibility to polyamide. Herein, we report a polyamide TFC membrane with enhanced interfacial stability and durable OSN performance, by multifunctional surface modification and in-situ interfacial polymerization on a hydrophobic and solvent-resistant polypropylene substrate. Distinct from nascent ones, the polypropylene substrates modified by tannic acid/aminopropyltriethoxysilane coating possess excellent hydrophilicity and more functional groups, in which the former allows for the in-situ synthesis of integral polyamide layers via interfacial polymerization and the latter greatly enhances the binding strength between the polyamide layer and PP substrate by 30 times. With this method, the TFC membranes exhibit excellent thermal stability in 80 °C dimethylformamide solution. Meanwhile, the TFC membranes display high ethanol permeance (9.2 L m−2 h−1 bar−1) and acid fuchsin rejection (98.5 %), outperforming the performance of most OSN membranes reported. This straightforward method, robust structural stability, and extraordinary performance make the TFC membranes a step closer to commercial OSN membranes.

Cofactor engineering in Thermoanaerobacterium aotearoense SCUT27 for maximizing ethanol yield and revealing an enzyme complex with high ferredoxin-NAD+ reductase activity

Thermoanaerobacterium aotearoense SCUT27 is a prominent producer of biofuels from lignocellulosic materials. To provide sufficient NAD(P)H for ethanol production, redox-related genes, including lactate dehydrogenase (ldh), redox-sensing transcriptional repressor (rex), and hydrogenase (hfsB), were knocked out. However, the growth of strain PRH (Δldh/Δrex/ΔhfsB) was suppressed due to the intracellular redox state imbalance with the increased NADH concentration. Coincidentally, when the Bcd–EtfAB (BCD) complex was overexpressed, the resulting strain PRH–B3 (Δldh/Δrex/ΔhfsB::BCD) grew rapidly and produced ethanol with a high yield. With lignocellulosic hydrolysates, PRH-BA (Δldh/Δrex/ΔhfsB::BCD::adhE) demonstrated high ethanol productivity and yield, reaching levels of 0.45–0.51 g/L/h and 0.46–0.53 g/g sugars, respectively. The study results shed light on the cofactor balance for cell stability and the high ferredoxin–NAD+ reductase activity of the BCD complex under an intracellular low redox state. They also provide an essential reference for developing strains for improved biofuel production.

Tannin-Tolerant Saccharomyces cerevisiae Isolated from Traditional Fermented Tea Leaf (Miang) and Application in Fruit Wine Fermentation Using Longan Juice Mixed with Seed Extract as Substrate.

This study focused on isolating tannin-tolerant yeasts from Miang, a fermented tea leaf product collected from northern Laos PDR, and investigating related food applications. From 43 Miang samples, six yeast isolates capable of ethanol production were obtained, with five isolates showing growth on YPD agar containing 4% (w/v) tannic acid. Molecular identification revealed three isolates as Saccharomyces cerevisiae (B5-1, B5-2, and C6-3), along with Candida tropicalis and Kazachstania humilis. Due to safety considerations, only Saccharomyces spp. were selected for further tannic acid tolerance study to advance food applications. Tannic acid at 1% (w/v) significantly influenced ethanol fermentation in all S. cerevisiae isolates. Notably, B5-2 and C6-3 showed high ethanol fermentation efficiency (2.5% w/v), while others were strongly inhibited. The application of tannin-tolerant yeasts in longan fruit wine (LFW) fermentation with longan seed extract (LSE) supplementation as a source of tannin revealed that C6-3 had the best efficacy for LFW fermentation. C6-3 showed promising efficacy, particularly with LSE supplementation, enhancing phenolic compounds, antioxidant activity, and inhibiting α-glucosidase activity, indicating potential antidiabetic properties. These findings underscore the potential of tannin-tolerant S. cerevisiae C6-3 for fermenting beverages from tannin-rich substrates like LSE, with implications for functional foods and nutraceuticals promoting health benefits.

High-resolution computation predicts that low dissolved CO concentrations and CO gradients promote ethanol production at industrial-scale gas fermentation

Gradients in dissolved gas concentrations are expected to affect the performance of large reactors for anaerobic gas (CO, H2, CO2) fermentation. To study how these gradients, and the dissolved gas concentration level itself, influence the productivity of the desired product ethanol and the product spectrum of C. autoethanogenum, we coupled a CFD model of an industrial-scale gas fermentor to a metabolic kinetic model for a wide range of metabolic regimes. Our model results, together with literature experimental data and a model with constant dissolved gas concentrations, indicate high ethanol specificity at low dissolved CO concentrations, with acetate reduction to ethanol at very low dissolved CO concentrations and combined ethanol and acetate production at higher CO concentrations. The gradient was predicted to increase both the biomass-specific ethanol production rate and the electron-to-ethanol yield by ∼25%. This might be due to intensified ferredoxin and NAD+ redox cycles, with the rate of the Rnf complex – a critical enzyme for energy conservation – as key driver towards ethanol production, all at the expense of a reduced flux to acetate. We present improved mechanistic understanding of the gas fermentation process, and novel leads for optimization and fundamental research, by coupling observations from various down-scaled lab experiments to expected microbial lifelines in an industrial-scale reactor.

Chronic Ethanol Decreases the Left Ventricular Cardiac Performance

Introduction: Spaced fiber bundles, less evident cell striations, deposition of collagen fiber bundles, and increased presence of fibroblasts in the cardiac tissue of rats that voluntarily and chronically ingested ethanol were observed by our research group. In addition, we observed increased proliferation and cell death of cardiomyocytes. To find out whether these changes lead to impaired heart functionality, some clinical tests were performed. Aim: to investigate whether chronic ethanol decreases the left ventricular performance assessed by exercise testing, electrocardiogram, and echocardiogram of male and female UChB strain rats. Material and methods: ten adult males and ten adult females, Wistar strain rats, named UChB (University of Chile), spontaneous high ethanol drinkers (consumption greater than 2 g ethanol / Kg body weight/day), and ten male UChB rats and ten adults female UChB rats, not exposed to ethanol, UChBC rats (controls) were used. Cardiac performance was evaluated by the stress test, electrocardiogram, and echocardiogram. Results: Exposed females showed ventricular morphological changes in the heart. The exposed females and males had the highest heart relative weight with females being larger than males. The exposed females showed altered electrocardiogram and echocardiogram. Conclusion: Chronic ethanol decreases the left ventricular cardiac performance in rats. Females are more sensitive to changes in cardiac electrical conduction.

The structure-activity relationship for the ABA triblock siloxane surfactant in aqueous-ethanol system

It is challenging to improve the foam stability in high concentration ethanol solution. In this paper, well-defined polyether-modified siloxane surfactants were synthesized, and their structures were characterized through infrared spectroscopy and one- and two-dimensional Nuclear magnetic resonance (NMR) spectroscopy. Furthermore, the relationships of between their chemical structure, surface activity, and foam property in high concentration ethanol solution were investigated in detail. The results showed that the target surfactant exhibited an ABA-type structure. They can effectively reduce the surface tension and produce the excellent foam in 75 % ethanol. In particular, these surfactants with loner siloxane chain confer strong foaming power in 75 % solution. This ability with good surface activity in water-ethanol system suggests a wide range of potential applications in low surface tension solvent system.

Search for protein kinase(s) related to cell growth or viability maintenance in the presence of ethanol in budding and fission yeasts.

Alcohol fermentation comprises two phases: phase 1, alcohol fermentation occurs while yeast cells proliferate; phase 2, growth stops and alcohol fermentation continues. We categorized genes related to proliferation in low ethanol (phase 1) and viability in high ethanol (phase 2) as Alcohol Growth Ability (AGA) and Alcohol Viability (ALV), respectively. Although genes required for phase 1 are examined in budding yeast, those for phase 2 are unknown. We set conditions for ALV screening, searched for protein kinases (PKs) related to ALV in budding yeast, and expanded two screenings to fission yeast. Bub1 kinase was important for proliferation in low ethanol but not for viability in high ethanol, suggesting that the important PKs differ between the two phases. It was indeed the case. Further, 3 common PKs were identified as AGA in both yeasts, suggesting that the important cellular mechanism in phase 1 is conserved in both yeasts, at least partially.

High Sensitivity Ethanol Gas Sensor Based on Hollow F-Doped SnO₂ Nanofibers

High Sensitivity Ethanol Gas Sensor Based on Hollow F-Doped SnO₂ Nanofibers

Influence of pH and temperature on the performance and microbial community during the production of medium-chain carboxylic acids using winery effluents as substrate.

Winery effluents containing high ethanol concentrations and diverse organic matter are ideal substrates for producing medium-chain carboxylic acids via fermentation and chain elongation. However, the process needs to be better understood. This study presents novel insights into the bioconversion mechanisms of medium-chain carboxylic acids by correlating fermentation and chain elongation kinetic profiles with the study of microbial communities at different pH (5 to 7) conditions and temperatures (30 to 40°C). It was found that high productivities of MCCA were obtained using a native culture and winery effluents as a natural substrate. Minor pH variations significantly affected the metabolic pathway of the microorganisms for MCCA production. The maximal productivities of hexanoic (715mg/L/d) and octanoic (350mg/L/d) acids were found at pH 6 and 35°C. Results evidence that the presence of Clostridium, Bacteroides, and Negativicutespromotes the high productions of MCCA. The formation of heptanoic acid was favor when Mogibacterium and Burkholderia were present.

Controlling Solvent Polarity to Regulate Protein Self-Assembly Morphology and Its Universal Insight for Fibrillation Mechanism.

The mechanism of ethanol-induced fibrillation of β-lactoglobulin (β-lg) in the acidic aqueous solution upon heating was investigated using various techniques, mainly thioflavin T fluorescence, atomic force microscopy, nonreducing electrophoresis, mass spectrometry, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy. The results showed that fibrillation occurred with a heating time increase, but high ethanol content slowed down the process. At a low ethanol volume fraction, peptides existed after heating for 2 h, with long and straight fibrils formed after 4-6 h, while at a high ethanol volume fraction, the proteins aggregated with very few peptides appeared at the early stage of heating, and short and curved fibrils formed after heating for 8 h. Ethanol weakened the hydrophobic interactions between proteins in the aqueous solution; therefore the latter could not completely balance the electrostatic repulsion, and thus suppressing the fibrillation process. It is believed that the fibrillation of β-lg in the acidic solution upon heating is mainly dominated by the polypeptide model; however, ethanol inhibited the hydrolysis of proteins, and the self-assembly mechanism changed to the monomer model.

Boosting the electroreduction of CO2 to liquid products via nanostructure engineering of Cu2O catalysts

The electrochemical reduction of CO2 presents a promising pathway for storing intermittent renewable energy in the form of chemical bonds, thereby mitigating CO2 emissions and enabling the production of sustainable fuels. In this work, we demonstrate nanoscale engineering of oxygen vacancy and morphology simultaneously on Cu2O catalysts for electrochemical reduction of CO2 to liquid products (formate and ethanol). By comparing the performance of cube- and tetrakaidecahedron-like Cu2O catalysts, we have demonstrated that the flower-like Cu2O catalyst, enclosed with rich oxygen vacancy defects, exhibited superior performance in the reduction of CO2 to liquid products. Moreover, the synergetic role of Cu+ also contributed to the enhanced activity by promoting CO2 adsorption and facilitating C–C coupling. As a result, the peak Faradaic efficiency (FE) for liquid products of 95.5 % was obtained, associated with a high ethanol FE of 52.6 % and formation rate of 23.8 μmol h−1 cm−2 within a H-cell. Furthermore, within a flow cell configuration, we have observed a significant improvement in the generation of formate, maintaining FE values above 70 % even under high current densities of up to 400 mA cm−2. In-situ Raman spectroscopic measurements allow us to identify and track key intermediates involved in the CO2 reduction to formate and ethanol. This detailed understanding of the reaction pathways adds to our fundamental knowledge and provides valuable insights for the development of morphology-controlled electrocatalysts targeting efficient conversion of CO2 into liquid products.

Bioethanol Production from Characterized Pre-treated Sugarcane Trash and Jatropha Agrowastes

Low production costs and a potential feedstock supply make lignocellulosic ethanol (bioethanol) an important source of advanced biofuels. The physical and chemical preparation of this kind of lignocellulosic feedstock led to a high ethanol yield. In order to increase the yield of fermentable sugars, pretreatment is an essential process step that alters the lignocellulosic structure and improves its accessibility for the expensive hydrolytic enzymes. In this context, the chemical composition of sugarcane trash (dry leaves, green leaves, and tops) and jatropha (shell and seed cake) was determined to be mainly cellulose, hemicellulose, and lignin. Hydrogen peroxide and sodium hydroxide were applied in an attempt to facilitate the solubilization of lignin and hemicelluloses in five agrowastes. The extraction of hydrogen peroxide was much better than that of sodium hydroxide. A comparative study was done using SEM, EDXA, and FTIR to evaluate the difference between the two methods. The pretreated wastes were subjected to saccharification by commercial cellulases (30 IU/g substrate). The obtained glucose was fortified with nutrients and fermented statically by Saccharomyces cerevisiae F-307 for bioethanol production. The results revealed the bioethanol yields were 325.4, 310.8, 282.9, 302.4 and 264.0 mg ethanol/g treated agrowastes from green leaves of sugarcane, jatropha deolied seed cake, tops sugarcane, dry leaves of sugarcane, and jatropha shell, respectively. This study emphasizes the value of lignocellulosic agricultural waste as a resource for the production of biofuels as well as the significance of the extraction process.

Effect of glucose–citric acid deep eutectic solvent on the vapor–liquid equilibrium of an aqueous ethanol solution

Objectives. To study the effect of a deep eutectic solvent (DES) based on glucose and citric acid on the vapor–liquid equilibrium of an aqueous solution of ethanol.Methods. A qualitative and quantitative analysis of the conditions of vapor–liquid equilibrium in an ethanol–water–DES ternary mixture was performed based on the open evaporation method and the measurement of TPxy data using a Świętosławski ebulliometer. Since the volatility of the DES is negligible in comparison with that of water and ethanol, the composition of the vapor phase was measured by means of Karl Fischer titration. The conditions of vapor–liquid phase equilibrium were modeled using the UNIFAC model.Results. The open evaporation method was used to determine the curves of residual concentrations for the ethanol–water–DES mixture at various DES concentrations and compositions (glucose–citric acid ratios). TPxy data was obtained for the mixture produced by adding 30 wt % DES to an aqueous solution of ethanol at atmospheric pressure. Studies show that DES based on glucose and citric acid has a significant effect on the relative volatility of ethanol in aqueous solution, leading to the disappearance of the azeotropic point. This effect is due to only the presence of glucose. Citric acid does not change the composition of the equilibrium phases, but rather increases the solubility of glucose in aqueous ethanol solutions. This is especially important at high ethanol concentrations, since glucose is poorly soluble in ethanol.Conclusions. Addition of DES based on glucose and citric acid to an aqueous solution of ethanol leads to the disappearance of the azeotropic point. DES can thus be considered as a promising entrainer for extracting ethanol from aqueous solutions using extractive distillation. Modeling of the conditions of vapor–liquid equilibrium in the ethanol–water–DES system using the UNIFAC model showed a satisfactory level of accuracy. The error in the calculated data increases with increasing the glucose concentration, while remaining acceptable for practical use.

High sensitivity low-temperature ethanol and acetone gas sensors based on silver/titanium oxide decorated laser-induced graphene

High sensitivity low-temperature ethanol and acetone gas sensors based on silver/titanium oxide decorated laser-induced graphene

The effect of high ethanol concentration on E-nose response for diabetes detection in exhaled breath: Laboratory studies

The growing number of people with diabetes has paved the way for the creation of non-invasive devices to measure blood glucose levels and enable the detection of diabetes non-invasively, for example, through exhaled air. This paper presents the development of a breath detection system using multiple sensors (e-nose system) for the non-invasive estimation of blood glucose levels. The system employs commercially available ethanol, CO2, and acetone sensors, with synthetic breath mixtures used for testing, including four scenarios with high ethanol concentrations (0–570 ppm) as an influence factor. Results showed a mean absolute error of 0.245 ppm when analysing commonly observed acetone concentrations in diabetic breath using four sensors and the XGBoost Regressor. In mixtures with high ethanol concentrations and varying acetone concentrations (0–8.62 ppm), the CatBoost Regressor outperformed other machine learning algorithms with a mean absolute error of 0.568 ppm. This study emphasises the significant impact of ethanol on acetone detection and the need to consider ethanol levels in the developing of non-invasive devices for blood glucose prediction based on the exhaled acetone measurements. The research shows that a set of three gas sensors is optimal for estimating acetone concentrations in gas mixtures. The presented results constitute a preliminary step towards developing a non-invasive device for estimating blood glucose levels based on breath analysis, with the novelty of considering alcohol intake as a potential influencing factor.

Kinetic migration of PBS and PBSA biopolymers prepared by cast film extrusion and biaxial stretching: A combined experimental and modeling approach

AbstractThe kinetic migration of poly(butylene succinate) (PBS) and poly(butylene succinate‐co‐adipate) (PBSA) biopolymers, prepared by cast film extrusion (thin film) and biaxial stretching (biaxially oriented [BO] film) techniques, were investigated based on experimental and mathematical modeling. MATLAB coding was used to fit the migration data to a diffusion model. BO films significantly reduced the migration rate compared with thin films, with reductions of 29% and 41% for BO‐PBS and BO‐PBSA, respectively, due to the increased degree of molecular crystallinity. Higher ethanol content increased the quantity of substance diffusing from plastic film. PBS and PBSA are more suitable for packaging hydrophilic foods than alcoholic beverages. PBS exhibited a lower migration rate than PBSA due to its more rigid polymer matrix. Remarkably, BO‐films exhibited 31% and 41% lower diffusion coefficients (D) compared with thin films, but significantly higher partition coefficients (KP,F) by 44% and 267% for BO‐PBS and BO‐PBSA, respectively. This suggests a stronger affinity of migrant for BO film matrix. However, at 70°C, PBSA films may be hydrolyzed with a high ethanol, resulting in an inadequate diffusion model. The diffusion–reaction concept should be implemented for a better fit. These findings provide valuable insights for selecting appropriate packaging materials and predicting migration under diverse conditions, ultimately promoting consumer safety.

Facile Synthesis of Fiber‐Reinforced Catalyst for High Performance Ethanol and 2‐Propanol Oxidation

In this study, Pd@TiO2 nanostructure is formed by using TiO2 fibers obtained by the electrospinning method and chemical reduction method, and this nanostructure is used in C2, and C3 alcohol oxidation studies as an application. In addition, TiO2 is compared with the Pd catalyst to investigate the effect of TiO2. In the results obtained, peak current values of 193 and 66.7 mA cm−2 for ethanol oxidation and 127.38 and 36.18 mA cm−2 for 2‐propanol oxidation are observed for Pd@TiO2 and Pd catalysts, respectively. With the addition of TiO2 to the structure, the electrocatalytic activity of C2 and C3 alcohol oxidations increases 3–3.5 times and contributes to the onset potential at an earlier potential. It also shows higher durability and stability in long‐term tests. Moreover, the addition of TiO2 to the structure enhances the electrocatalytic activity and provides high current density and long‐term stability in alcohol oxidation. These results show that fibrous structures in combination with metals improve the effect of catalysts and exhibit high potential for their application in alcohol fuel cells.

Optimization of Bioactive Compound Extraction from Saffron Petals Using Ultrasound-Assisted Acidified Ethanol Solvent: Adding Value to Food Waste.

The saffron industry produces large by-products, including petals with potential bioactive compounds, which are cheap and abundant, making them an attractive alternative to expensive stigmas for extracting bioactive components. This study aimed to optimize the extraction conditions of bioactive compounds from vacuum-dried saffron petals using an ultrasound-assisted acidified ethanol solvent. Three factors were considered: ethanol concentration (0-96%), citric acid concentration in the final solvent (0-1%), and ultrasound power (0-400 watt). This study examined the effects of these factors on parameters like maximum antioxidant activity, total anthocyanin content, total phenolic content, and the total flavonoid content of the extraction. This study found that saffron petal extract's antioxidant activity increases with higher ethanol concentration, citric acid dose, and ultrasound power, but that an increased water content leads to non-antioxidant compounds. Increasing the dosage of citric acid improved the extraction of cyanidin-3-glucoside at different ultrasound power levels. The highest extraction was achieved with 400 watts of ultrasound power and 1% citric acid. Ethanol concentration did not affect anthocyanin extraction. Higher ethanol concentration and greater citric acid concentration doses resulted in the maximum extraction of total phenolic content, with a noticeable drop in extraction at higher purity levels. This study found that increasing the proportion of citric acid in the final solvent did not affect flavonoid extraction at high ethanol concentration levels, and the highest efficiency was observed at 200 watts of ultrasound power. The optimum values of the independent parameters for extracting bioactive compounds from saffron petals included 96% ethanol concentration, 0.67% citric acid concentration, and 216 watts of ultrasound power, resulting in a desirability value of 0.82. This ultrasound-assisted acidified ethanolic extract can be used in the food industry as a natural antioxidant and pigment source.

Fractionation of flavonols and anthocyanins in winemaking residues using molecularly imprinted cellulose‐synthetic hybrid particles with pyridyl active surface

AbstractHybrid cellulose‐synthetic particles with surface active pyridyl moieties and molecularly imprinted cavities for quercetin were prepared via atom transfer radical polymerization. The functionalization of the materials with pyridyl groups was confirmed by FTIR and the SEM micrographs of the hybrid particles demonstrate a clear surface modification compared with the pristine cellulose. Competitive sorption/desorption testing of the imprinted and non‐imprinted particles with standard polyphenols show the achievement of an imprinting factor IF ∼8. Moreover, it was also confirmed the high retention capability of the hybrid materials for polyphenols, due to their strong binding with the surface pyridyl moieties, even when using hydroalcoholic solvents of high ethanol content (e.g., ethanol/water 80/20 v/v). The sorption capabilities of the synthesized materials for polyphenols were explored with the fractionation of flavonols and anthocyanins in winemaking residues. High concentration and enrichment factors were achieved for high‐added value compounds, namely five times for quercetin and 12 for quercetin‐3‐O‐glucuronide with a diatomaceous earth extract and up to 4 for flavonols in a grape pomace (e.g. myricetin and quercetin glucosides). This research demonstrates the feasibility for the combination between the development of engineered materials addressing sustainability with their application to the valorization of agro‐industrial wastes.

Fermentation of whey-derived matrices by Kluyveromyces marxianus: alcoholic beverage development from whey and fruit juice mixes.

This research paper addresses the hypotheses that Kluyveromyces marxianus can be cultured with good alcohol production on different whey-derived matrices, and that the fermented product can be used in order to develop alcoholic beverages with acceptable sensory characteristics by mixtures with yeast-fermented fruit-based matrices. Growth and fermentative characteristics of Kluyveromyces marxianus LFIQK1 in different whey-derived matrices were explored by culturing (24 h, 30°C) on reconstituted whey, demineralized whey, heat-treated whey and milk permeate media. High lactose consumption, ethanol production and yield were observed. Reconstituted whey matrix was selected for mixing with orange or strawberry juices fermented using Saccharomyces cerevisiae to obtain alcoholic beverages (W-OR and W-ST, respectively). Consumer evaluation of beverages was performed using acceptability and Check-All-That-Apply (CATA) questions. Good acceptance was observed, significantly higher for W-ST than for W-OR. CATA questions gave information about organoleptic characteristics of beverages. Penalty analysis showed W-R and W-ST were positively associated with smooth/refreshing and fruity/natural, respectively. Liking was represented, accordingly with penalty analysis, by natural/refreshing. A novel alternative for utilization of whey and whey-related matrices by alcoholic beverages production with natural ingredients is presented.