Low Concentrations Of Ethanol Research Articles

Nanosecond Pulse-Driven Oxygen Bubble Plasma Activation of Low-Concentration Alcohol Solutions and its Sterilization Mechanism.

To address the current use of high-concentration (70-75%) alcohol solutions as disinfectants, which are known for their drawbacks such as flammability and strong odor, a new approach based on nanosecond pulse-driven bubble discharge in low-concentration ethanol solutions is proposed. Research findings indicate that O2 bubble plasma activated ethanol solution (PAES) exhibits superior sterilization efficacy. A 3 min treatment using 10% alcohol eliminated all bacteria (reducing the bacterial count by 7 orders of magnitude) with an energy requirement of only 10.9 J/ml, whereas the same treatment with air PAES achieved less than a one-order reduction and O2/N2/air plasma activated water (PAW) achieved even less. Furthermore, to delve deeper into the key factors of PAES sterilization, concentrations of inorganic reactive species (H2O2, NO2 -, NO3 -, ONOO-, pH) and organic components resulting from alcohol decomposition (CH3CHO, CH3CH2OH, CH3COOH, and CH3COOOH) were analyzed using assay kits and GC-MS. Their variations at different storage temperatures (4 °C and -20 °C) were compared with the corresponding bactericidal effects. The results identified peroxyacetic acid (CH3COOOH) as a key bactericidal factor in PAES, showing that CH3COOOH over time at different storage temperatures correlated with their bactericidal effects. The study also revealed that O2 PAES stored at -20 °C maintained complete bacterial elimination even after 4 days. Therefore, PAES has the potential to replace high-concentration alcohol solutions for sterilization.

Tolerance and efficient metabolization of extremely high ethanol concentrations by a social wasp

Ethanol, a natural by-product of sugar fermentation, can be found in various fruits and nectar. Although many animals routinely consume ethanol in low concentrations as part of their natural diets, its inherent toxicity can cause severe damage. Even species particularly well adapted to ethanol consumption face detrimental effects when exposed to concentrations above 4%. Here, we investigated the metabolism of ethanol and its impact on survival and behavior in the Oriental hornet (Vespa orientalis), a social wasp that naturally consumes ethanol. We show that chronic ethanol consumption, even at concentrations as high as 80%, had no impact on hornet mortality, construction behavior, or agonistic behavior. Using 13C1 labeled ethanol, we show that hornets efficiently metabolized ingested ethanol and at a much higher rate than honey bees. The presence of multiple copies of the alcohol dehydrogenase (NADP+) gene in the Vespa genera suggests a potential mechanism for ethanol tolerance. These findings support the hypothesis that the mutualistic relationship between ethanol-producing organisms and vespid hosts may be at the origin of their remarkable capacity to utilize and metabolize ethanol.

Is malting an absolute must? Native triticale as a stand-in for barley malt in the brewing process.

To remain competitive, brewers must innovate by incorporating novel elements beyond traditional styles. Thus, exploring triticale as a modern substitute for barley malt is promising, especially given its higher amylolytic activity compared to barley. This study aimed to assess the impact of substituting up to 50% of barley malt with unmalted triticale on green beer quality, encompassing multiple stages from wort production to primary fermentation at a laboratory scale. Triticale-based worts (ratios 10-50%) had lower extract content than 100% barley malt. However, incorporating 10% of triticale led to only a 1% decrease in extract content compared to the all-malt wort. Shearzyme® 500L, an endo-1,4-β-xylanase with β-glucanase side activity, effectively addressed wort viscosity by breaking down arabinoxylans and β-glucans in triticale cell walls. All triticale-based beers exhibited lower ethanol content compared to reference beer, as is typical when using adjuncts. In green beer, a 50% triticale ratio lowered ethanol content by 16% (without enzyme) and 19% (with enzyme) compared to 100% malt beer. However, green beer with 10% triticale had satisfactory levels of total polyphenol and vicinal diketone content, among other parameters. Commercial enzyme application significantly enhanced proteolytic activity within the grain. Fermentations of enzyme-treated worts showed higher amino acid levels, further confirming the increased proteolytic activity facilitated by the chosen enzyme. Overall, this study provides a comprehensive analysis of the brewing process using native triticale. Building on this foundation, future studies will focus on optimizing mashing conditions to enhance the fermentation profile of the wort. © 2024 Society of Chemical Industry.

Zinc oxide-based sensor prepared by modified sol–gel route for detection of low concentrations of ethanol, methanol, acetone, and formaldehyde

Abstract We4 4 We received the acceptance date as 26 September 2024. Could you please update it to reflect this exact date for our project, instead of 1 October 2024? This is very important for our project funding. successfully synthesized zinc oxide (ZnO) nanoparticles using the sol–gel method, followed by their application onto alumina substrates for sensor testing. Comprehensive characterization of the nanomaterials was carried out utilizing XRD, SEM, TEM, UV–VIS-IR, and Photoluminescence (PL) techniques. The nanoparticles displayed a hexagonal wurtzite crystal structure, typical of ZnO. UV–Vis-IR spectroscopy revealed significant absorption in the UV region, with the band gap energy calculated to be 3.22 eV. PL spectra indicated the presence of various defects, such as oxygen vacancies and zinc interstitials, within the ZnO structure. SEM analysis of the deposited film surface showed spherical agglomerates, confirming the nanoscale dimensions, while energy-dispersive x-ray spectroscopy spectra affirmed the high purity of the ZnO films, rich in Zn and O elements. Sensor tests demonstrated the ZnO sensor’s high sensitivity to low concentrations of volatile organic compounds such as ethanol, formaldehyde, methanol, and acetone. Notably, at an operational temperature of 300 °C, the sensor exhibited a remarkable response to 5 ppm of each gas, with the following response and response/recovery times: for methanol, 11.47 and 36 s/57 s; for acetone, 11.54 and 25 s/52 s; for formaldehyde, 0.79 and 53 s/58 s; and for ethanol, 3.88 and 9 s/59 s.

Effect of ethanol content, water injection, and compression ratio on combustion and detailed emissions in an SI-GDI engine

The transportation sector accounts for 29 % of the total greenhouse gas emissions produced in the US. Steadily tightening criteria emissions and fuel efficiency requirements have led to current research efforts evaluating multiple mixed strategies or extending beyond traditional engine architectures and fuels. Ethanol is used extensively as both a fuel additive and primary fuel replacement for gasoline. Modern engines utilizing boosting or high compression ratios require fuels such as ethanol that are more resistant to pre-ignition to operate efficiently at high load conditions. Water dilution has historically been used for knock reduction and some potential has been found for emissions and efficiency improvements. The studies on these topics, however, often focus on wide-open-throttle (WOT) conditions and neglect part load where engines normally operate. This investigation evaluates the combined effects of fuel ethanol content, compression ratio, and water dilution on the combustion and emissions characteristics A 2.4L 4-cylinder naturally aspirated (NA) gasoline direct injection (GDI) engine at part load conditions.The results indicated that the varied combinations of compression ratio and fuel ethanol content did not change the typical performance or emissions results expected for either parameter alone. Water dilution only significantly degraded stability at conditions with coefficient of variation (CoV) of indicated mean effective pressure (IMEP) values near or above 3 %. Water dilution at 10 % and 20 % W/F rations reduced average oxides of nitrogen (NOx) emissions by 20 % and 40 % respectively. The water dilution effect on unburned hydrocarbons (UHCs) was more mixed with flame ionization detector (FID) results showing mixed positive and negative effects for lower ethanol content fuels and up to a 20 % increase in UHC emissions with the high ethanol fuel (E85). Fourier transform infrared (FTIR) results agreed with the fuel blend UHC sensitivity reported with the FID. Ethanol emissions were found to increase by two to three times more for each level of water dilution than unburned gasoline emissions.

Optimizing Oxygen Exposure during Kombucha Brewing Using Air-Permeable Silicone Bags

As the commercial and home brewing of kombucha expands to accommodate its increased popularity, novel brewing practices that generate non-alcoholic kombucha in an efficient manner become valuable. The research presented in this work compares kombucha brewed in a glass jar brewing vessel to that brewed in an air-permeable silicone bag. Identical kombucha ferments with various sugar food sources were prepared and placed in each vessel, and variables such as titratable acidity, pH, alcohol by volume, gluconic acid concentration, acetic acid concentration, and sugar content were studied as a function of time. The results indicated that, regardless of the food source, kombucha brewed in an air-permeable bag exhibited more efficient acid production, lower ethanol concentration, and greater sugar utilization relative to equivalent kombucha brewed in a jar.

Bioethanol production from cassava fed-batch fermentation in pervaporation membrane bioreactor with permeate fractional condensation

A new type pervaporation membrane bioreactor was developed by coupling cassava-based fed-batch fermentation and pervaporation membrane separation technology for bioethanol production. Membrane separation slowed down broth accumulation rate and mitigated ethanol product inhibition. The fermentation time, average sugar consumption rate, ethanol production and ethanol productivity were 131h, 6.6 gL-1h-1, 149.4 gL-1 and 2.5 gL-1h-1, respectively. They were improved by 55.9 %, 73.2 %, 32.3 % and 49.7 %, respectively, compared to those of conventional fed-batch fermentation. The average membrane flux and separation factor were 711.3 gm-2h-1 and 6.5, respectively, with an ethanol concentration of 24.4 wt% in the permeate. Throughout fermentation, the total mass transfer coefficient remained constant at 9.6 × 10-6 ms-1, with the convection mass transfer coefficient decreasing as the broth viscosity increasing while the membrane mass transfer coefficient slightly increasing. A two-stage condensation downstream the membrane achieved fractional vapor recovery. The primary condensate with low ethanol concentration (1.6 wt%) can be used for cassava hydrolyzation, saving 14.0 % of water requirement. Recovering ethanol from the high-concentration (32.6 wt%) secondary condensate required lower energy (46 %) compared to direct recovery from the total permeate.

Enhance Ethanol Sensing Performance of Fe-Doped Tetragonal SnO2 Films on Glass Substrate with a Proposed Mathematical Model for Diffusion in Porous Media.

This research enhances ethanol sensing with Fe-doped tetragonal SnO2 films on glass, improving gas sensor reliability and sensitivity. The primary objective was to improve the sensitivity and operational efficiency of SnO2 sensors through Fe doping. The SnO2 sensors were synthesized using a flexible and adaptable method that allows for precise doping control, with energy-dispersive X-ray spectroscopy (EDX) confirming homogeneous Fe distribution within the SnO2 matrix. A morphological analysis showed a surface structure ideal for gas sensing. The results demonstrated significant improvement in ethanol response (1 to 20 ppm) and lower temperatures compared to undoped SnO2 sensors. The Fe-doped sensors exhibited higher sensitivity, enabling the detection of low ethanol concentrations and showing rapid response and recovery times. These findings suggest that Fe doping enhances the interaction between ethanol molecules and the sensor surface, improving performance. A mathematical model based on diffusion in porous media was employed to further analyze and optimize sensor performance. The model considers the diffusion of ethanol molecules through the porous SnO2 matrix, considering factors such as surface morphology and doping concentration. Additionally, the choice of electrode material plays a crucial role in extending the sensor's lifespan, highlighting the importance of material selection in sensor design.

Conformations of a highly expressed Z19 α-zein studied with AlphaFold2 and MD simulations.

α-zeins are amphiphilic maize seed storage proteins with material properties suitable for a multitude of applications e.g., in renewable plastics, foods, therapeutics and additive manufacturing (3D-printing). To exploit their full potential, molecular-level insights are essential. The difficulties in experimental atomic-resolution characterization of α-zeins have resulted in a diversity of published molecular models. However, deep-learning α-zein models are largely unexplored. Therefore, this work studies an AlphaFold2 (AF2) model of a highly expressed α-zein using molecular dynamics (MD) simulations. The sequence of the α-zein cZ19C2 gave a loosely packed AF2 model with 7 α-helical segments connected by turns/loops. Compact tertiary structure was limited to a C-terminal bundle of three α-helices, each showing notable agreement with a published consensus sequence. Aiming to chart possible α-zein conformations in practically relevant solvents, rather than the native solid-state, the AF2 model was subjected to MD simulations in water/ethanol mixtures with varying ethanol concentrations. Despite giving structurally diverse endpoints, the simulations showed several patterns: In water and low ethanol concentrations, the model rapidly formed compact globular structures, largely preserving the C-terminal bundle. At ≥ 50 mol% ethanol, extended conformations prevailed, consistent with previous SAXS studies. Tertiary structure was partially stabilized in water and low ethanol concentrations, but was disrupted in ≥ 50 mol% ethanol. Aggregated results indicated minor increases in helicity with ethanol concentration. β-sheet content was consistently low (∼1%) across all conditions. Beyond structural dynamics, the rapid formation of branched α-zein aggregates in aqueous environments was highlighted. Furthermore, aqueous simulations revealed favorable interactions between the protein and the crosslinking agent glycidyl methacrylate (GMA). The proximity of GMA epoxide carbons and side chain hydroxyl oxygens simultaneously suggested accessible reactive sites in compact α-zein conformations and pre-reaction geometries for methacrylation. The findings may assist in expanding the applications of these technologically significant proteins, e.g., by guiding chemical modifications.

A study of the migration behavior of formaldehyde in different concentrations of ethanol in paper food materials.

To ensure the safety of food contact materials, a liquid chromatography method was established to determine the migration of formaldehyde in paper packaging with various food simulants (10%, 25%, 50%, 75%, and 95% ethanol by volume) and to investigate the migration behavior of formaldehyde after various durations and with various materials. The results showed that the method has good linearity with a correlation coefficient of R2 > 0.9990, a detection limit of 0.0011 ~ 0.0027mg L-1, and a spiked recovery of 89.7 ~ 103.2% in the range of formaldehyde determination; the migration of formaldehyde in all six paper contact materials showed a trend of gradual increase with time until equilibrium was reached. At the same time and temperature, the migration of formaldehyde in paper packaging was the highest in low-concentration ethanol. With the same food simulants and materials, the maximum migration of formaldehyde in printed materials was greater than that in nonprinted materials; with different materials and the same food simulant, the thickness value was higher, with the use of water-based ink as a printing material, and the maximum migration value of formaldehyde by offset printing technology was low.

Manufacturing process of liposomal Formation: A coarse-grained molecular dynamics simulation

A method of producing liposomes has been previously developed using a continuous manufacturing technology that involves a co-axial turbulent jet in co-flow. In this study, coarse-grained molecular dynamics (CG-MD) simulations were used to gain a deeper understanding of how the self-assembly process of liposomes is affected by the material attributes (such as the concentration of ethanol) and the process parameters (such as temperature), while also providing detailed information on a nano-scale molecular level. Specifically, the CG-MD simulations yield a comprehensive internal view of the structure and formation mechanisms of liposomes containing DPPC, DPPG, and cholesterol molecules. The importance of this work is that structural details on the molecular level are proposed, and such detail is not possible to obtain through experimental studies alone. The assessment of structural properties, including the area per lipid, diffusion coefficient, and order parameters, indicated that a thicker bilayer was observed at higher ethanol concentrations, while a thinner bilayer was present at higher temperatures. These conditions led to more water penetrating the interior of the bilayer and an unstable structure, as indicated by a larger contact area between lipids and water, and a higher coefficient of lipid lateral diffusion. However, stable liposomes were found through these evaluations at lower ethanol concentrations and/or lower process temperatures. Furthermore, the CG-MD model was further compared and validated with experimental and computational data including liposomal bilayer thickness and area per lipid measurements.

Role of L-PGDS in Light Alcohol Consumption-Induced Cerebral Angiogenesis in Male Mice

Ischemic stroke is one of the leading causes of death and permanent disability. Promoting cerebral angiogenesis before or after ischemic stroke reduces ischemic brain damage and improves functional recovery. Alcohol is one of the most commonly consumed chemical substances. Light alcohol consumption (LAC) reduces the incidence and improves the prognosis of ischemic stroke. Recently, we found that LAC promotes cerebral angiogenesis under basal conditions and following ischemic stroke. In addition, LAC upregulates lipocalin-type prostaglandin D2 synthase (L-PGDS), the principal PGH2 isomerase mainly expressed in the central nervous and cardiovascular systems. Therefore, we determined the role of L-PGDS in LAC-induced cerebral angiogenesis. In in vitro studies, low-concentration ethanol significantly upregulated L-PGDS and increased angiogenic capability (tube formation, migration, and proliferation) in cultured C57BL/6J mouse brain microvascular endothelial cells (MBMVECs). AT-56, a selective L-PGDS inhibitor, abolished the increased angiogenic capability. In in vivo studies, 8-week gavage feeding with low-dose ethanol significantly upregulated L-PGDS and increased vessel density and vessel branches in the cerebral cortex and subcortical area under physiological conditions and following ischemic stroke in C57BL/6J male mice. AT-56 and endothelial cell-specific L-PGDS conditional knockout did not affect vessel density and vessel branches of the cerebral cortex and subcortical area in water-fed control mice but alleviated the proangiogenic effect in low-dose ethanol-fed mice under basal conditions and following ischemic stroke. Therefore, our findings suggest that L-PGDS may be crucial in LAC-induced cerebral angiogenesis. NIH 2R01AA023610. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Impact of immature coffee fruits and water addition during spontaneous fermentation process: Chemical composition and sensory profile

BackgroundCoffee fermentation process influences the final coffee composition and the sensory aspects which define the quality of the beverage. In this study, coffee fruits underwent spontaneous self-induced anaerobic fermentation using samples with two percentages of immature fruits in submerged and solid-state processing. The effects on the physicochemical composition and sensory quality of coffees were evaluated. ResultsThe two percentages of immature fruits corresponded to 11.0 and 0.3% of unripe fruits. The percentage of immature fruits significantly altered the initial content of sugars (sucrose, glucose, and fructose), ash, and titratable acidity. The water addition during the fermentative process did not significantly influence final moisture, proteins, citric acid, and propionic acid concentrations. Compared to the solid-state, the submerged process gave rise to coffees with lower concentrations of ethanol, glycerol, ash, lipids, succinic, and acetic acids. Coffee fermented with 0.3% of immature fruits showed higher lactic acid production in submerged fermentation (67.44 mg/g), and higher concentrations of ethanol (42.84 mg/g) and glycerol (1.68 mg/g) in solid-state fermentation. All coffees produced were classified as specialty coffees with a score above 84 points. However, the submerged fermented coffee with 11% immature fruit stood out with notes of caramel, brown sugar, honey, orange, lemon, floral, nut, yellow and red fruits. ConclusionsThis study confirmed that spontaneous fermentation can be used to produce specialty coffees. Differentiation in sensory attributes can be achieved through the addition of water and varying the percentage of green fruits during the fermentation process. Up to 11% of immature fruits did not compromise coffee quality.How to cite: Ferreira LJC, Casé IN, Bertarini PLL, et al. Impact of immature coffee fruits and water addition during spontaneous fermentation process: Chemical composition and sensory profile. Electron J Biotechnol 2024;69. https://doi.org/10.1016/j.ejbt.2024.04.001.

Facile synthesis of oxygen vacancies mediated Co3O4 by Mn doping for high-performance ethanol sensing

The detection of volatile organic compounds (VOCs) at extremely low concentrations holds significant importance in industry and daily life. In this study, Mn-doped Co3O4 materials with a mesoporous structure and oxygen vacancies were synthesized through manual grinding and calcination treatment. The structural characterization measurements showed that Mn doping restrained the crystal growth of the cobaltous oxides which was beneficial for the mesoporous structure, and appropriate oxygen vacancies. The 0.2Mn–Co3O4 sensor operated at the optimum operating temperature of 260 °C, showed a higher response (32.0) to 30 ppm ethanol, which was about 5.81 times as much as that of the pure Co3O4 (5.5). Additionally, to ethanol the 0.2Mn–Co3O4 sensor manifested ultra-low detection limit (11.6 ppb), fast response/recovery time (25/15 s) and superior stability. These exceptional performances may be attributed to the synergistic effect of mesoporous structure formation and appropriate oxygen vacancy concentration. Consequently, the Mn-doped Co3O4 sensor has great potential for detecting low-concentration ethanol in practical applications.

Long‐term evaluation of hydrocarbon degradation rates within the source zone under natural and enhanced attenuation for site closure purposes

AbstractDespite addressing the cleanup of petroleum hydrocarbon contamination plumes in groundwater, challenges with site closure persist due to the ongoing long‐term contaminant release from source zones. Thus, source zone monitoring even in the presence of residual light nonaqueous‐phase liquid (LNAPL) is mandated by many countries' regulatory agencies before site closure. In this study, four independent controlled‐release sites, each containing a particular fraction of ethanol in gasoline, that is, 10%, 24%, 25%, and 85% (v/v), were subjected to monitored natural attenuation (MNA) alone (E24 and E85), and with nitrate (E25) and sulfate (E10) biostimulation at the vicinity of the source zone. To the best of the authors' knowledge, this is the longest controlled gasohol release monitoring study performed to date at the source zone for site closure (nearly 18 years of monitoring). Both natural source zone depletion and biostimulation were found to reduce benzene concentrations to acceptable remediation target levels according to environmental regulatory councils. Benzene biodegradation rates (λs) were one order of magnitude higher than those reported in the literature for diluted concentrations in groundwater plumes. The decay rate of benzene varied between 0.45 and 1.75/year and was strongly influenced by the mass of ethanol. Compared to biostimulation with nitrate (half‐life of 1.52 years), MNA alone resulted in faster benzene removal rates (half‐life of 0.96 years). Anaerobic biostimulation with sulfate had negligible effects on benzene, toluene, ethylbenzene, and xylene (o‐, m‐, and p‐xylene [BTEX]) biodegradation compared to natural attenuation alone. The highest ethanol concentration (E85) led to faster benzene removal (with a half‐life of 0.40 years), which was even higher than MNA under lower ethanol concentrations (E24). Benzene half‐life was 2.2‐fold slower in the site with the lowest ethanol (E10) compared to E85, indicating that the negative effects of ethanol on BTEX biodegradation appeared to be short‐lived and may need to be re‐evaluated over the long term. Benzene decay rates were approximately six times slower in the source zone than the rates obtained for groundwater plumes, emphasizing the importance of targeting the LNAPL after plume retreat. The study's findings can assist practitioners in better predicting the lines of evidence for BTEX bioremediation and remediation cleanup times at a lower cost in the presence of ethanol, as well as providing guidance for determining whether biostimulation is necessary to expedite source zone remediation for site closure.

Porphyromonas gingivalis Strain W83 Infection Induces Liver Injury in Experimental Alcohol-Associated Liver Disease (ALD) in Mice

The liver plays a vital role in the defense against infections. Porphyromonas gingivalis (P. gingivalis), a dominant etiologic oral bacterium implicated in periodontal disease (PD), has been associated with various systemic diseases. This study aimed to investigate the influence of P. gingivalis on alcohol-associated liver diseases (ALD). Mice were fed a Lieber–DeCarli liquid diet containing 5% ethanol for 10 days after an initial adaptation period on a diet with lower ethanol content for 7 days. Two days before tissue sample collection, the mice were administered P. gingivalis strain W83 (Pg) through intraperitoneal injection (IP). Pair-fed mice with Pg infection (PF+Pg) exhibited an activated immune response to combat infections. However, alcohol-fed mice with Pg infection (AF+Pg) showed liver injury with noticeable abscess lesions and elevated serum alanine aminotransferase (ALT) levels. Additionally, these mice displayed liver infiltration of inflammatory monocytes and significant downregulation of proinflammatory cytokine gene expression levels; and AF+Pg mice also demonstrated increased intrahepatic neutrophil infiltration, as confirmed by chloroacetate esterase (CAE) staining, along with elevated gene expression levels of neutrophil cytosol factor 1 (Ncf1), neutrophilic inflammation driver lipocalin 2 (Lcn2), and complement component C5a receptor 1 (C5ar1), which are associated with neutrophilic inflammation. Interestingly, compared to PF+Pg mice, the livers of AF+Pg mice exhibited downregulation of gene expression levels of NADPH oxidase 2 (Cybb), the leukocyte adhesion molecule Cd18, and the Toll-like receptor adaptor Myd88. Consequently, impaired clearance of P. gingivalis and other bacteria in the liver, increased susceptibility to infections, and inflammation-associated hepatic necrotic cell death were observed in AF+Pg mice, which is likely to have facilitated immune cell infiltration and contributed to liver injury. Furthermore, in addition to the Srebf1/Fasn pathway induced by alcohol feeding, Pg infection also activated carbohydrate response element-binding protein (ChREBP) in AF+Pg mice. In summary, this study demonstrates that P. gingivalis infection, acting as a “second hit”, induces dysfunction of immune response and impairs the clearance of bacteria and infections in alcohol-sensitized livers. This process drives the development of liver injury.

Purification, characterization of a plant esterase from red kidney bean and its feasibility for pesticide residue analysis in foods

Plant-derived esterase is a promising alternative enzyme source for pesticide residue analysis. The present study aimed to obtain purified red kidney bean esterase (RKBE), investigate its biochemical properties and application potential in pesticide residue assay. RKBE was extracted and purified by simple aqueous two-phase extraction combined with dextran gel filtration chromatography, with specific activity of 11.845 U/mg and purification fold of 18.952. SDS-PAGE revealed that RKBE has a molecular weight of 33 kDa. Preliminary structural characterization showed the amino acid sequence of RKBE was similar to that of α/β-hydrolase (ESW18998) derived from Phaseolus vulgaris with 19.5% sequence coverage, and the relative contents of β-sheet, β-turn, α-helix, and random coil were 22.69%, 24.19%, 30.12%, and 23.00%, respectively. The optimal pH and temperature of RKBE were 6.5 and 40 °C. Ca2+, Mg2+, Zn2+, and low concentrations of methanol and ethanol stimulated the enzyme activity. The half-life was 138.6 days at −20 °C. Kinetic studies showed that RKBE exhibited a high affinity and catalytic activity towards 1-naphthyl acetate, with a Km of 0.277 mM and a Kcat/Km of 0.455 s−1 mM−1. Enzyme-specific inhibition assay indicated RKBE to be a carboxylesterase. Finally, pesticide susceptibility experiments confirmed that organophosphorus and carbamate pesticides exerted inhibitory effects on RKBE catalytic activity. For methamidophos, methomyl, dichlorvos, and carbaryl, the limit of detection (IC10) values in cabbage were 0.0031, 0.0045, 0.001, and 0.0065 mg/kg, respectively, suggesting that RKBE can serve as a new, widely available and cost-effective enzyme source for pesticide residual assay in foods.

Cell disruption of Chlorella sp. and Ecklonia maxima biomass for bioethanol production using Saccharomyces cerevisiae

The demand for bioethanol has increased over the years due to the high costs of fossil fuels, which have been associated with environmental deterioration, leading to the need for cheaper and cleaner biofuel sources. To address this issue, this study investigated micro (Chlorella sp.) and macroalgal (Ecklonia maxima) biomass cell disruption for subsequent bioethanol production using Saccharomyces cerevisiae. Different biomass concentrations of 1.25, 2.5, 3.75 and 5%w/v were prepared, and cell disrupted using ultrasonication and steam extraction for 10, 20, 30 and 40 mins. The samples were analysed for reducing sugar concentrations where the steam-extracted samples produced the highest reducing sugars of 8980 mg/L and 1800 mg/L for Chlorella sp. and E. maxima biomasses respectively. The extracts from ultrasonication and steam extraction were fermented for a period of 96 h where the steam-extracted extracts produced the highest ethanol concentrations from Chlorella sp. and E. maxima biomasses, at the maximum ethanol concentrations of 7 300 mg/L and 689.2 mg/L respectively. The findings of this paper showed that steam extraction is a preferred biomass pretreatment method since its extracts yielded higher ethanol concentrations while the ultrasonicated extracts produced lower ethanol concentrations.

An on-chip microarray platform for material-temperature optimization and gas discrimination

The demand for gases detection has promoted extensive research into gas sensors. Sensor arrays can be used as electronic olfaction units for complex gas detection and identification. However, the gas sensing properties are affected by various factors. The multi-dimensional nature of those interactions is crucial for creating a sensor array with diverse responses, but it is also challenging to fabricate an array considering all these parameters, particularly in miniaturization. In this paper, we present a framework that can take multiple factors into consideration and help to fabricate an optimal array for gas identification. 32 sensors including different MOS materials (SnO2, In2O3, WO3), morphologies (microsphere, nanoparticle, nanoflake), doped/loaded metals (Pd, Pt, Ce, Ru, Rb), and operational temperatures (250℃∼370℃) are discussed. A material-temperature-analyte-response database was then established by storing their response characteristics towards low ppm concentrations of ammonia, ethyl acetate, toluene, methanol, ethanol, and acetone. An optimized array was then constructed out of 10,518,300 possible combinations of materials and operational temperatures. Results showed improvements in discrimination ability and the optimized array integrated into the chip can provide vector signals with high selectivity, completely recognizing all the 6 target gases and even for their multi-component mixture after linear discriminant analysis transformation.

Wide-range ethanol sensor based on a spray-deposited nanostructured ZnO and Sn–doped ZnO films

This study compares the performance of a highly sensitive ethanol sensor incorporating a zinc oxide (ZnO) nanostructured film with that of (1–3) % tin-doped zinc oxide (Sn–ZnO) nanostructured films across a wide range of ethanol concentrations from 0.5 to 400 ppm. X-ray diffraction analysis confirms the polycrystalline structure of Sn–ZnO films, with a significant (002) plane orientation. Notably, Sn doping reduces the optical bandgap from 3.28 eV (ZnO) to 2.41 eV (3% Sn–ZnO). Ethanol vapor sensing experiments reveal that the 2% Sn–ZnO film operates at a lower temperature of 220 °C compared to the ZnO film (290 °C). Particularly, the 2% Sn–ZnO film exhibits rapid and strong responses to low ethanol concentrations (0.5–100 ppm) at this temperature. Response values of 2.22 ± 0.01 and 17.66 ± 0.08 with response times of 11 ± 1 and 15 ± 1 s are achieved at ethanol concentrations of 0.5 and 400 ppm, respectively. Conversely, the ZnO film performs better at higher ethanol concentrations (150–400 ppm). These findings advance gas sensing mechanisms in ZnO and Sn–ZnO films, with implications for future advancements in gas sensor technology.