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Because the volatile content of isoamyl alcohol increases sharply on the seventh day of wheat mildew infection, isoamyl alcohol can be used as an early biomarker of wheat mildew infection. Currently, only a few sensors for isoamyl alcohol detection have been reported, and these sensors still suffer from low sensitivity and poor moisture resistance. Herein, the isoamyl alcohol sensitivity of 5 at% Er@LaFeO3 (ELFO) was enhanced by loading Ag nanoparticles on the surface of the ELFO microspheres, while the optimal operating temperature was reduced. The moisture resistance of Ag/ELFO was improved by the incorporation of g-C3N4 nanosheets (NSs) on the surface of Ag/ELFO through electrostatic self-assembly. Given the requirements for practical applications in grain granaries, the sensing behavior of a Ag/ELFO-based sensor incorporating g-C3N4 NSs at 20% relative humidity (RH) was systematically studied, and the sensor demonstrated excellent repeatability, long-term stability, and superior selectivity (791 at 50 ppm) for isoamyl alcohol with a low limit of detection (LOD = 75 ppb). Furthermore, the practical results obtained for wheat at different mildew stages further confirmed the potential of the g-C3N4/Ag/ELFO-based sensor for monitoring the early mildew stage of wheat. This work may offer guidance for enhancing the moisture resistance of gas-sensitive materials through the strategy of employing composite nanomaterials.

In order to separate phenol from water, at 101.3 kPa, the liquid-liquid equilibria (LLE) data of water + phenol + solvents (trichloromethane, isoamyl alcohol) were obtained at 298.15, 303.15, and 313.15 K. The ability of the extractant to extract phenol from water was evaluated by the distribution coefficient (D) and selectivity coefficient (S). The Bachman and Hand equations were used to verify the reliability of the LLE data with the linear coefficient was greater than 0.98%. The LLE data was correlated with the NRTL and UNIQUAC models to obtain a binary interaction parameter with an RMSD not greater than 0.36%. [ABSTRACT FROM AUTHOR]

The development of one-step deposition technology for metal oxide-based coatings is significant for the rapid fabrication of gas sensors. Gas sensors based on LaFeO3 were fabricated by solution precursor plasma spraying (SPPS) strategy. Through a comparative analysis of material composition and cross-sectional morphology, we have determined the optimal spray distance (8 cm), ensuring the highest level of thickness uniformity in the coating (17.13 ± 0.34 μm). Furthermore, the influence of the number of passes on coating morphology and gas sensing performance was investigated. The optimal gas sensor possessed a higher response to isoamyl alcohol (236 at 25 ppm) at 250 °C. Meanwhile, excellent selectivity, repeatability, long-term stability (431.6 ± 9.2 at 60 ppm for 20 days), and a low limit of detection (144 ppb) were obtained. The superior low-concentration (< 25 ppm) gas-sensing performance should be ascribed to the loose porous morphology with uniform thickness and the higher surface activity of the optimal coating. Moreover, the practical experiment demonstrated the application potential of the sensors for monitoring wheat mildew. This work may provide a direction for the characteristic gas detection of wheat mildew and a successful case for the deposition of LaFeO3 coating by SPPS. [ABSTRACT FROM AUTHOR]

Isoamyl alcohol is a precursor of isoamyl acetate, an aromatic compound that imparts the ginjo aroma to sake. The isoamyl alcohol biosynthesis pathway in yeasts involves the genes PDC1 , PDC5 , PDC6 , ARO10 , and THI3 encoding enzymes that decarboxylate α-ketoisocaproic acid to isovaleraldehyde. Among these genes, THI3 is the main gene involved in isoamyl alcohol biosynthesis. Decreased production of isoamyl alcohol has been reported in yeast strains with disrupted THI 3 (Δ thi3). However, it has also been reported that high THI3 expression did not enhance decarboxylase activity. Therefore, the involvement of THI3 in isoamyl alcohol biosynthesis remains unclear. In this study, we investigated the role of THI3 in isoamyl alcohol biosynthesis. While reproducing previous reports of reduced isoamyl alcohol production by the Δ thi3 strain, we observed that the decrease in isoamyl alcohol production occurred only at low yeast nitrogen base concentrations in the medium. Upon investigating individual yeast nitrogen base components, we found that the isoamyl alcohol production by the Δ thi3 strain reduced when thiamine concentrations in the medium were low. Under low-thiamine conditions, both thiamine and thiamine diphosphate (TPP) levels decreased in Δ thi3 cells. We also found that the decarboxylase activity of cell-free extracts of the Δ thi3 strain cultured in a low-thiamine medium was lower than that of the wild-type strain, but was restored to the level of the wild-type strain when TPP was added. These results indicate that the loss of THI3 lowers the supply of TPP, a cofactor for decarboxylases, resulting in decreased isoamyl alcohol production. [ABSTRACT FROM AUTHOR]

Higher alcohols (phenylethyl alcohol and isoamyl alcohol), as the crucial aroma compounds, have been found to associate with the sensory properties of various alcoholic products. The Ehrlich and Harris pathways are the main pathways for yeast to produce phenylethyl alcohol and isoamyl alcohol during the brewing process of alcoholic products, whereas the specific changes of the Ehrlich and Harris pathways in Wickerhamomyces anomalus under ethanol stress are still unclear. In this study, W. anomalus NCU003 with a high capacity for aroma compound production was treated with ethanol stress at different concentrations (3%, v/v, 6%, v/v and 9%, v/v) to study the effects on the expression levels of genes and metabolite content in the Ehrlich and Harris pathways. The results found that ethanol stress inhibited the production of phenylethyl alcohol and isoamyl alcohol, and the content decreased with the increase of ethanol concentrations. In the meantime, the up‐regulation of ARO1, CS, ARO8, Leu1, BAT2 and ilvs family genes in the Ehrlich and Harris pathways could lead to an increase in the synthesis of important precursor substances during the synthesis of phenylethyl alcohol and isoamyl alcohol. However, the significant down‐regulation of ARO10, PDC, ADH1 and AHD2 genes was the main reason for the low production of phenylethyl alcohol and isoamyl alcohol. These results could provide a theoretical reference for the construction of genetic engineering strains of W. anomalus in the future so as to reasonably control the content of higher alcohols during the brewing process of alcoholic products. [ABSTRACT FROM AUTHOR]

Isoamyl alcohol is a clear, unpleasantly odorous, colorless liquid of higher alcohol that emits a fruity aroma when heavily diluted. It has received much attention in recent years as a new fuel with a high energy density. Isoamyl alcohol can be produced industrially by microbial fermentation. Still, its toxicity to host cells has limited its potential for industrial production, and the molecular mechanism of its toxic effects has not yet been elucidated. In this study, RNA-Seq technology was used to analyze the transcripts of Saccharomyces cerevisiae under normal conditions and in the presence of isoamyl alcohol (0.5 g/L and 2.5 g/L). The results showed that the expression of the cell wall (CCW12, BGL2, NCW2 and SUN4), cell membrane (ELO1, ERG2, FAA1, and OPI3), translation and other structural genes were significantly down-regulated. The expression of genes related to ATP biosynthesis, NADPH biosynthesis (ZWF1), and metal ion transport (PMC1) proteins were up-regulated. Strains with key genes knocked out were cultured without isoamyl alcohol. Combined results suggested that isoamyl alcohol may affect cell wall stability and cell membrane fluidity, and the expression of genes related to ion homeostasis and energy production may play a protective role against isoamyl alcohol stress. By maintaining cell wall stability/membrane fluidity under isoamyl alcohol pressure, improving certain ion homeostasis, and generating energy/NADPH, it is possible to overcome the toxicity of isoamyl alcohol in industrial fermentation processes to a certain extent. [ABSTRACT FROM AUTHOR]

Simple Summary: Plant volatile traps designed for Lepidoptera pests caught a large number of flies as non-target insects that provided an opportunity to study their odour preferences. The tested isoamyl alcohol-based semisynthetic bisexual lure containing red wine as an organic component attracted flies of 10 families, including economically important ones such as Drosophilidae and Ulididae, and it is the first reported attractant of the Sciomyzidae family. Although our phenylacetaldehyde-based synthetic lure attracted less families with lower abundance, it was efficient against the Empididae and Milichiidae families. In the case of Heleomyzidae flies, both lures were efficient, and these are the first published attractants of this family. These new data on the chemical ecology of flies serve as a basis for further studies and may be utilized in the development of sampling methods used in biological and integrated pest management, and faunistic and ecological studies. During field tests implemented in Transcarpathia (West Ukraine) in 2015, 6501 specimens belonging to 26 Brachyceran fly families were collected with traps baited with generic lures (originally developed for noctuid moths) based on fermenting liquid and floral compounds. Isoamyl alcohol-based baits generally attracted more flies than phenylacetaldehyde-based baits and unbaited controls; however, the phenylacetaldehyde-based traps were the most attractive to the Empididae and Milichiidae families. The isoamyl alcohol-based semisynthetic lure showed significant attractivity to the families of Muscidae, Ulidiidae, Sarcophagidae, Calliphoridae, Sciomyzidae, Heleomyzidae, Drosophilidae, Phoridae and Platystomatidae. Additionally, isoamyl alcohol-based semisynthetic lure is the first reported attractant of the Sciomyzidae family. Since our phenylacetaldehyde-based floral lure was also attractive to Heleomyzidae flies, both types of lures can be seen as the first known attractants of this family. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Isoamyl alcohol is an important biomass fermentation product that can be used as a gasoline surrogate, jet fuel precursor, and platform molecule for the synthesis of fine chemicals and pharmaceuticals. This study reports on the use of graphene oxide immobilized membra (GOIMs) for the recovery of isoamyl alcohol from an aqueous matrix. The separation was performed using air-sparged membrane distillation (ASMD). In contrast to a conventional PTFE membrane, which exhibited minimal separation, preferential adsorption on graphene oxide within GOIMs resulted in highly selective isoamyl alcohol separation. The separation factor reached 6.7, along with a flux as high as 1.12 kg/m2 h. Notably, the overall mass transfer coefficients indicated improvements with a GOIM. Optimization via response surfaces showed curvature effects for the separation factor due to the interaction effects. An empirical model was generated based on regression equations to predict the flux and separation factor. This study demonstrates the potential of GOIMs and ASMD for the efficient recovery of higher alcohols from aqueous solutions, highlighting the practical applications of these techniques for the production of biofuels and bioproducts.

Isoamyl alcohol is a clear, unpleasantly odorous, colorless liquid of higher alcohol that emits a fruity aroma when heavily diluted. It has received much attention in recent years as a new fuel with a high energy density. Isoamyl alcohol can be produced industrially by microbial fermentation. Still, its toxicity to host cells has limited its potential for industrial production, and the molecular mechanism of its toxic effects has not yet been elucidated. In this study, RNA-Seq technology was used to analyze the transcripts of Saccharomyces cerevisiae under normal conditions and in the presence of isoamyl alcohol (0.5 g/L and 2.5 g/L). The results showed that the expression of the cell wall (CCW12, BGL2, NCW2 and SUN4), cell membrane (ELO1, ERG2, FAA1, and OPI3), translation and other structural genes were significantly down-regulated. The expression of genes related to ATP biosynthesis, NADPH biosynthesis (ZWF1), and metal ion transport (PMC1) proteins were up-regulated. Strains with key genes knocked out were cultured without isoamyl alcohol. Combined results suggested that isoamyl alcohol may affect cell wall stability and cell membrane fluidity, and the expression of genes related to ion homeostasis and energy production may play a protective role against isoamyl alcohol stress. By maintaining cell wall stability/membrane fluidity under isoamyl alcohol pressure, improving certain ion homeostasis, and generating energy/NADPH, it is possible to overcome the toxicity of isoamyl alcohol in industrial fermentation processes to a certain extent.

In this experimental study, biodiesel was synthesized from the salmon oil using the Lipozyme®RM IM (Bagsværd, Denmark) as a biocatalyst. Isoamyl alcohol was used as an acyl acceptor in the transesterification process. The aim of this study is to select the best process conditions, aiming to obtain the highest transesterification degree that meets the requirements of the EN 14214 standard. Response surface methodology (RSM) was used for statistical analysis and optimization of process parameters. A four-factor experimental design was modelled by central compositional design (CCD) to investigate the effects of biocatalyst concentration, isoamyl alcohol-to-oil molar ratio, temperature, and duration on transesterification degree. It was determined that the optimal parameters for biodiesel synthesis were the following: an enzyme concentration of 11% (wt. of oil mass); a process temperature of 45 °C; a process duration of 4 h; and an alcohol-to-oil molar ratio of 6:1. The transesterification degree of biodiesel reached 87.23%. The stepwise addition of isoamyl alcohol during the transesterification process further increased the degree of transesterification to 96.5%. [ABSTRACT FROM AUTHOR]

Microemulsions have been widely used in multidisciplinary fields, yet reverse water-in-oil microemulsions are traditionally dispersed in petroleum-based oil solvents. For greener approaches, it should be also feasible to use less toxic, bio-based hydrocarbon solvents as continuous oil phase. Herein, reverse microemulsions in different alkanes, middle-chain alkanols, middle-chain esters or combinations of nonpolar solvent with alkanol are compared, using Aerosol-OT as common surfactant. As model of bio-based solvents, ethyl caprylate, isoamyl acetate and isoamyl alcohol are proposed as a more sustainable approach of oil solvents. Various characterization techniques were used to compare the properties and stability of reverse microemulsions for the different oil phase compositions, ranging from ternary phase diagrams to conductometry and turbidity titrations, micro-Differential Scanning Calorimetry and cryo-Scanning Electron Microscopy. As sustainable application, these microemulsions in bio-based solvents were proved suitable as template phase for the synthesis of cross-linked chitosan nanoparticles. The sizes of the resulting biopolymer nanoparticles were characterized by Dynamic Light Scattering and Atomic Force Microscopy, so that the effect of different crosslinkers and different the oil phase compositions was also compared. Thus, the use bio-based alkyl esters can provide similar microemulsion properties as the conventional alkanes, especially when using a combination of nonpolar solvents with alkanols. [Display omitted] • Water-in-oil microemulsions compared with different oil solvents. • Bio-based solvents as alternative to petroleum-based oil solvents. • Ethyl caprylate and isoamyl acetate as bio-based esters were compared with alkanes. • Isoamyl alcohol as bio-based alkanol was compared with petroleum-based alcohols. • Chitosan nanoparticles cross-linked by glutaraldehyde or citrate in microemulsions. [ABSTRACT FROM AUTHOR]

The introduction in modern breweries of tall cylindroconical fermentors, replacing the traditional open fermentation vats, unexpectedly revealed strong inhibition of flavor production by the high CO2 pressure in the fermentors. We have screened our collection of Saccharomyces cerevisiae strains for strains displaying elevated tolerance to inhibition of flavor production by 10.65 bar CO2, using a laboratory scale CO2 pressurized fermentation system. We focused on the production of isoamyl acetate, a highly desirable flavor compound conferring fruity banana flavor in beer and other alcoholic beverages, from its precursor isoamyl alcohol (IAAc/Alc ratio). We selected the most tolerant Saccharomyces cerevisiae strain, saké yeast Kyokai no. 1, isolated a stable haploid segregant seg63 with the same high IAAc/Alc ratio under CO2 pressure, crossed seg63 with the unrelated inferior strain ER7A and phenotyped 185 haploid segregants, of which 28 displaying a high IAAc/Alc ratio were pooled. Mapping of Quantitative Trait Loci (QTLs) by whole-genome sequence analysis based on SNP variant frequency revealed two QTLs. In the major QTL, reciprocal hemizygosity analysis identified MDS3 as the causative mutant gene, a putative member of the TOR signaling pathway. The MDS3Seg.63 allele was dominant and contained a single causative point mutation, T2171C, resulting in the F274S substitution. Introduction of MDS3Seg.63 in an industrial tetraploid lager yeast with CRISPR/Cas9 enhanced isoamyl acetate production by 145% under CO2 pressure. This work shows the strong potential of polygenic analysis and targeted genetic modification for creation of cisgenic industrial brewer's yeast strains with specifically improved traits. [ABSTRACT FROM AUTHOR]

During field tests implemented in Transcarpathia (West Ukraine) in 2015, 6501 specimens belonging to 26 Brachyceran fly families were collected with traps baited with generic lures (originally developed for noctuid moths) based on fermenting liquid and floral compounds. Isoamyl alcohol-based baits generally attracted more flies than phenylacetaldehyde-based baits and unbaited controls; however, the phenylacetaldehyde-based traps were the most attractive to the Empididae and Milichiidae families. The isoamyl alcohol-based semisynthetic lure showed significant attractivity to the families of Muscidae, Ulidiidae, Sarcophagidae, Calliphoridae, Sciomyzidae, Heleomyzidae, Drosophilidae, Phoridae and Platystomatidae. Additionally, isoamyl alcohol-based semisynthetic lure is the first reported attractant of the Sciomyzidae family. Since our phenylacetaldehyde-based floral lure was also attractive to Heleomyzidae flies, both types of lures can be seen as the first known attractants of this family.

Enzymatic synthesis of short-chain esters (flavours) might enable their labelling as natural, increasing their value. Covalently immobilised Rhizopus oryzae lipase (EO-proROL) was used to synthesise isoamyl butyrate and acetate. In cyclohexane, the best performer reaction solvent, 1.8 times higher yield of isoamyl butyrate (ca. 100%) than isoamyl acetate (ca. 55%) was obtained. Optimum initial acid concentration (410 mM) and acid:alcohol mole ratio (0.5) were established by a central composite rotatable design to maximise isoamyl butyrate single-batch and cumulative production with reused enzyme. These conditions were used to scale up the esterification (150 mL) and to assess yield, initial esterification rate, productivity and enzyme operational stability. Commercial isoamyl alcohol and fusel oil results were found to be similar as regards yield (91% vs. 84%), initial reaction rate (5.4 µM min−1 with both substrates), operational stability (40% activity loss after five runs with both) and productivity (31.09 vs. 28.7 mM h−1). EO-proROL specificity for the structural isomers of isoamyl alcohol was also evaluated. Thus, a successful biocatalyst and product conditions ready to be used for isoamyl ester industrial production are here proposed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background In biological cells, promoters drive gene expression by specific binding of RNA polymerase. They determine the starting position, timing and level of gene expression. Therefore, rational fine-tuning of promoters to regulate the expression levels of target genes for optimizing biosynthetic pathways in metabolic engineering has recently become an active area of research. Results In this study, we systematically detected and characterized the common promoter elements in the unconventional yeast Yarrowia lipolytica, and constructed an artificial hybrid promoter library that covers a wide range of promoter strength. The results indicate that the hybrid promoter strength can be fine-tuned by promoter elements, namely, upstream activation sequences (UAS), TATA box and core promoter. Notably, the UASs of Saccharomyces cerevisiae promoters were reported for the first time to be functionally transferred to Y. lipolytica. Subsequently, using the production of a versatile platform chemical isoamyl alcohol as a test study, the hybrid promoter library was applied to optimize the biosynthesis pathway expression in Y. lipolytica. By expressing the key pathway gene, ScARO10, with the promoter library, 1.1–30.3 folds increase in the isoamyl alcohol titer over that of the control strain Y. lipolytica Po1g KU70∆ was achieved. Interestingly, the highest titer increase was attained with a weak promoter P UAS1B4-EXPm to express ScARO10. These results suggest that our hybrid promoter library can be a powerful toolkit for identifying optimum promoters for expressing metabolic pathways in Y. lipolytica. Conclusion We envision that this promoter engineering strategy and the rationally engineered promoters constructed in this study could also be extended to other non-model fungi for strain improvement.

In order to separate o-cresol from wastewater and supplement the related parameters of o-cresol + solvent (isoamyl alcohol), the liquid–liquid equilibrium (LLE) data of isoamyl alcohol + o-cresol + water was determined at 298.2, 308.2 and 318.2 K, under 101.3 kPa. Comparing the distribution coefficients (D) and separation factors (S) of isoamyl alcohol, it is found that the isoamyl alcohol was great for extracting o-cresol from water. The consistency was verified by the Othmer–Tobias and Hand equations. Meanwhile, the NRTL and UNIQUAC thermodynamic models of this system were correlated using Aspen Plus 8.4. The root mean square deviation (RMSD) values were less than 0.42%. In addition, the reliability of regression parameters was verified using the GUI-MATLAB tool. [ABSTRACT FROM AUTHOR]

In this experimental study, biodiesel was synthesized from the salmon oil using the Lipozyme®RM IM (Bagsværd, Denmark) as a biocatalyst. Isoamyl alcohol was used as an acyl acceptor in the transesterification process. The aim of this study is to select the best process conditions, aiming to obtain the highest transesterification degree that meets the requirements of the EN 14214 standard. Response surface methodology (RSM) was used for statistical analysis and optimization of process parameters. A four-factor experimental design was modelled by central compositional design (CCD) to investigate the effects of biocatalyst concentration, isoamyl alcohol-to-oil molar ratio, temperature, and duration on transesterification degree. It was determined that the optimal parameters for biodiesel synthesis were the following: an enzyme concentration of 11% (wt. of oil mass); a process temperature of 45 °C; a process duration of 4 h; and an alcohol-to-oil molar ratio of 6:1. The transesterification degree of biodiesel reached 87.23%. The stepwise addition of isoamyl alcohol during the transesterification process further increased the degree of transesterification to 96.5%.

Background: In biological cells, promoters drive gene expression by specific binding of RNA polymerase. They determine the starting position, timing and level of gene expression. Therefore, rational fine-tuning of promoters to regulate the expression levels of target genes for optimizing biosynthetic pathways in metabolic engineering has recently become an active area of research. Results: In this study, we systematically detected and characterized the common promoter elements in the unconventional yeast Yarrowia lipolytica, and constructed an artificial hybrid promoter library that covers a wide range of promoter strength. The results indicate that the hybrid promoter strength can be fine-tuned by promoter elements, namely, upstream activation sequences (UAS), TATA box and core promoter. Notably, the UASs of Saccharomyces cerevisiae promoters were reported for the first time to be functionally transferred to Y. lipolytica. Subsequently, using the production of a versatile platform chemical isoamyl alcohol as a test study, the hybrid promoter library was applied to optimize the biosynthesis pathway expression in Y. lipolytica. By expressing the key pathway gene, ScARO10, with the promoter library, 1.1–30.3 folds increase in the isoamyl alcohol titer over that of the control strain Y. lipolytica Po1g KU70∆ was achieved. Interestingly, the highest titer increase was attained with a weak promoter PUAS1B4-EXPm to express ScARO10. These results suggest that our hybrid promoter library can be a powerful toolkit for identifying optimum promoters for expressing metabolic pathways in Y. lipolytica. Conclusion: We envision that this promoter engineering strategy and the rationally engineered promoters constructed in this study could also be extended to other non-model fungi for strain improvement. [ABSTRACT FROM AUTHOR]

Equilibrium and kinetic experiments were performed for gallic acid recovery using tributyl phosphate dissolved in isoamyl alcohol as a diluent. Employing an extractive-reaction system results in significantly higher acid recovery in comparison to physical extraction. Overall equilibrium extraction complexation constant KE was found to be in the range 4.325–6.896. 1:1 acid: extractant complexes are proposed from the results obtained from mass action law model. Adsorption isotherm models (Langmuir, Freundlich, Temkin) and Response Surface Methodology was used, Mass transfer coefficient (kL) and diffusivity coefficient were also calculated. Extraction kinetics was observed to be very slow based on the Hatta number. [ABSTRACT FROM AUTHOR]

Fusel oil, a residue from ethanol production, can be used as a source of alcohol in the synthesis of biodiesel. Babassu oil is a Brazilian native plant that has high oil productivity, and its use in transesterification reactions may be a source of triglycerides. This study aimed to purify fusel oil in order to obtain isoamyl alcohol for use in the alkali-transesterification reaction with babassu oil. Purification of fusel oil was promising since achieving 96% purity in the content of isoamyl alcohol, adding value to the said residue, was possible. The reaction of babassu oil with isoamyl alcohol showed 94% conversion into esters and was higher than that with soybean oil, which showed 86% conversion, under the same reaction conditions at 25 °C, 1 h, and oil: alcohol ratio of 1:10. These temperature conditions are considered mild for obtaining biodiesel, which is obtained at higher temperatures when larger chain alcohols are used. Physicochemical properties were in line with the literature and met the standards. [ABSTRACT FROM AUTHOR]

Annualy, helminthic diseases are one of the causes of economic losses in agriculture. Ruminantia are most often observed to be infected with nematodes of the gastrointestinal tract, including Strongyloides papillosus and the representatives of the Strongylida order. Identifying factors which could cause a decrease in the level of infection of agricultural animals with helminthiases would allow stock-raising facilities to regularly achieve high quality dairy and meat production in sufficient quantity. On the basis of this study, we determined the impact of flavourings and source materials approved for use in and on foods (isoamyl alcohol, isoamyl acetate, raspberry ketone, trilon B, methylparaben) on the survivability of larvae of Strongyloides papillosus and Haemonchus contortus, parasitic nematodes of Ruminantia animals. Among these substances, the lowest efficiency against the nematode larvae was found in isoamyl alcohol, isoamyl acetate and trilon B. A stronger effect was caused by methylparaben (for L3 S. papillosus LD50 = 0.67 ± 0.04%, L1 and L2 S. papillosus – LD50 = 0.0038 ± 0.0008%, L3 H. contortus – LD50 = 0.89 ± 0.15%). Minimum efficient dosage of the solutions was 10 g/l. Significant antihelminthic properties were manifested by raspberry ketone (for L3 S. papillosus LD50 = 1.00 ± 0.72%, L1 and L2 S. papillosus – LD50 = 0.07 ± 0.06%, L3 H. contortus – LD50 = 0.39 ± 0.26%). The results show that there is considerable potential for further studies on the antiparasitic properties of these substances against nematodes in the conditions of farming enterprises and agricultural complexes.

The olive fruit fly, Bactrocera oleae (Rossi) is economically the most important olive pest, causing yield losses in all olive growing areas where is detected. Considering that EU requires the reduction of pesticide use by up to 100% by 2050, more effective non-pesticide lures for B. oleae monitoring and/or controlling are needed. This research was aimed at investigating the attractiveness of different blends of olive fruit fly-associated yeast volatiles toward B. oleae. Three blends of olive fruit fly-associated yeast volatiles: isoamyl alcohol and 2-phenethyl alcohol; isoamyl alcohol, 2-phenethyl alcohol and 2-phenethyl acetate; and isoamyl alcohol, 2-phenethyl acetate and isobutyl acetate were selected and tested on yellow sticky traps for attraction of B. oleae in olive orchard. Results showed that traps containing all tested blends of olive fruit fly-associated yeast volatile compounds, in total, were significantly more attractive to B. oleae and were not significantly attractive to green lacewings, compared to the control. Among them, the most promising was the one containing the blend of isoamyl alcohol, 2-phenethyl acetate and isobutyl acetate because its attractiveness was constantly significant during investigation compared to the others. This blend in the future could lead us to the discovery of a new attractant for the monitoring and/or controlling of B. oleae.

Like other branched-chain higher alcohols used as biofuels, isoamyl alcohol has attracted considerable attention because of its advantages, which include high energy density, low hygroscopicity, and compatibility with the current infrastructure. Previous attempts to increase the microbial production of isoamyl alcohol have yielded great progress, but the existing methods of detecting isoamyl alcohol based on gas chromatography and high-performance liquid chromatography are laborious and time-consuming. In this study, we developed a simple colorimetric assay to determine high isoamyl alcohol–producing strains. The assay was based on isoamyl alcohol oxidase and peroxidase (IAOP assay) and could be performed in microplate with high throughput and had a specific detection range of 0–20 mM. Characterization analysis revealed that the developed IAOP assay was highly specific for isoamyl alcohol relative to other branched-chain alcohols. Little interference with the assay was observed from the fermentation media, microorganisms, and fermentation byproducts (e.g., lactic acid, acetic acid). We conclude that the enzyme-based IAOP assay can be used for high-throughput monitoring of strains that produce isoamyl alcohol and could be adjusted to screen for strains that produce many other metabolites. [ABSTRACT FROM AUTHOR]

The performance of a semisynthetic bisexual lure (SBL, containing isoamyl alcohol, acetic acid and red wine) previously found attractive for a number of noctuids was compared with that of the respective synthetic sex attractants of Orthosia cerasi (=stabilis), O. cruda, O. gothica, O. incerta, Anorthoa munda and Conistra vaccini. The respective sex attractants performed significantly better in the Orthosia spp. than the SBL lure, which, although regularly catching low numbers of both females and males, did not differ significantly from zero catch in unbaited control traps. On the other hand, the SBL lure performed as well as the sex attractant in C. vaccini. Sizeable catches of C. rubiginea, C. rubiginosa and C. erythrocephala were also recorded in traps with the SBL lure. The SBL lure can prove to be a useful tool in ecological and faunistical studies of Conistra and related hibernating Xylenini species. [ABSTRACT FROM AUTHOR]

The values of density (ρ), viscosity (η) and speed of sound (u) were measured for binary mixtures of 3-methyl-1-butanol (isoamyl alcohol) with n-butylamine (NBA), sec-butylamine (SBA), tert-butylamine (TBA), n-hexylamine (NHA) and n-octyl amine (NOA) over the entire range of mole fractions and at three temperatures (298.15, 303.15 and 308.15 K). From these measurements, the values of excess molar volume(VE), viscosity deviation (∆η), deviation in isentropic compressibility (∆ks), excess Gibbs free energy of activation of viscous flow (G*E) and Grungberg–Nissan interaction parameter (d′) have been calculated. The excess parameter deviations are fitted to Redlich–Kister-type polynomial equation using multi-parametric nonlinear regression analysis to estimate the binary coefficients and standard deviations. The results were discussed in terms of molecular interactions, dipole–dipole interactions and H-bond interactions between unlike molecules. Further, the effects of temperature and amine group in different amines were also studied for the binary mixtures. [ABSTRACT FROM AUTHOR]

Cr-modified ZSM-5 molecular sieve catalysts were prepared by the methods of hydrothermal technique [Cr-ZSM-5(H)], ion-exchange [Cr-ZSM-5(E)] and impregnation [Cr-ZSM-5(I)], the catalytic performance of the prepared catalysts in the process of isoamyl alcohol to isovaleric acid was investigated, and their physicochemical properties were characterized by XRD, FT-IR, BET, SEM and TG. The results showed that the catalyst Cr-ZSM-5(H) exhibited higher activity with isoamyl alcohol conversion of 44.97%, isovaleric acid selectivity of 78.78% and isovaleric acid yield of 35.43%, superior to Cr-ZSM-5(E) and Cr-ZSM-5(I), because of its suitable pore diameter, slower deposition rate, and more Cr-incorporation. [ABSTRACT FROM AUTHOR]

• Solubility and physical properties data for soybean oil (SO) and alcohol mixtures. • The cloud point method allowed the determination of the binodal curves. • The Jouyban-Acree model could describe density and viscosity. • n-Butanol and isoamyl alcohol enhanced the ethanol–SO mixture interaction. • Higher alcohol presented an equivalent effect on the system's solubility. Mixtures of soybean oil (SO) and ethanol (EtOH) are of interest for several applications, such as the addition of the mixtures to diesel, the production of ethyl esters (ethyl biodiesel) from SO and the extraction of vegetable oils with a renewable solvent. However, the solubility between the components of this mixture is limited, which may hinder the possible applications. Thus, the present study aimed to determine the solubility of mixtures composed of SO and EtOH with the addition of cosolvents, n-butanol (nBut) and isoamyl alcohol (IAA), which are higher alcohols present in fusel oil, a coproduct of the production of EtOH. The physical properties of the ternary mixtures were also determined, which are necessary data for proposing the use of these renewable inputs. The regions of phase separation for the systems were determined using the cloud point method at constant temperature (25, 40 and 55 °C). The physical properties, density (ρ, kg·m−3) and dynamic viscosity (η, mPa·s) were experimentally determined for the binary (EtOH + nBut and EtOH + IAA, temperatures from 20.0 to 70.0 ± 0.1 °C) and ternary (SO + EtOH + nBut and SO + EtOH + IAA, 25.0, 40.0 and 55.0 ± 0.1 °C) mixtures. The experimental ρ data were described mathematically by the simple mixing rule (SMR) and the Jouyban-Acree (JA) model. For the description of η, the modified Kay rule (MKR), the Kendall and Monroe (KM) model, the Grunberg-Nissan (GN) model and the JA model were considered. Regarding the binary mixtures, the SMR and the GN model showed the lowest average relative deviation (ARD) values, 0 to 0.31% for ρ and 0.21 to 5% for η. For the ternary systems, the JA model best described the behavior of both physical properties (ARD from 0.02 to 4.51% for ρ and from 0.85 to 7.14% for η). Both cosolvents enabled the reduction of the immiscibility region, with similar performance in the evaluated temperature range. [ABSTRACT FROM AUTHOR]

Isoamyl alcohol is an important biomass fermentation product that can be used as a gasoline surrogate, jet fuel precursor, and platform molecule for the synthesis of fine chemicals and pharmaceuticals. This study reports on the use of graphene oxide immobilized membra (GOIMs) for the recovery of isoamyl alcohol from an aqueous matrix. The separation was performed using air-sparged membrane distillation (ASMD). In contrast to a conventional PTFE membrane, which exhibited minimal separation, preferential adsorption on graphene oxide within GOIMs resulted in highly selective isoamyl alcohol separation. The separation factor reached 6.7, along with a flux as high as 1.12 kg/m 2 h. Notably, the overall mass transfer coefficients indicated improvements with a GOIM. Optimization via response surfaces showed curvature effects for the separation factor due to the interaction effects. An empirical model was generated based on regression equations to predict the flux and separation factor. This study demonstrates the potential of GOIMs and ASMD for the efficient recovery of higher alcohols from aqueous solutions, highlighting the practical applications of these techniques for the production of biofuels and bioproducts.

A two-stage process for producing isoprene from isoamyl alcohol has been developed through the successive implementation of the steps of dehydration of isoamyl alcohol and dehydrogenation of resulting isoamylenes using porous ceramic converters obtained by self-propagating high-temperature synthesis, with the converter pores bearing Fe–Cr systems synthesized by the sol–gel technique and containing subnanosized iron and chromium particles. It has been shown that the bimetallic catalytic system obtained by separate deposition of Fe and Cr has the highest activity toward the isoamylenes studied in the dehydrogenation reaction; on this catalyst system using 24-fold dilution with water and a temperature of 600°C, the isoprene yield is up to ~10%, selectivity is ~23%, and productivity is ~0.13 Lisoprene/(h gact.comp). The conversion of the isoamylene fraction is 46%. [ABSTRACT FROM AUTHOR]

Abstract Simulated fusel oil containing a mixture of ethyl (11.2%), butyl (10.6%) and isoamyl alcohols (78.2%) was used to obtain lubricant esters from palm kernel oil by enzymatic route using lipase from Burkholderia cepacia immobilized on epoxy matrix silica-hydroxyethyl cellulose as a biocatalyst. Runs were performed under both batch and continuous mode to determine the influence of oil-to alcohol molar ratio on the ester concentrations using as a model isoamyl alcohol as acyl acceptor. The optimum oil to alcohol molar ratio was 1:4 and high isoamyl esters formation (99 wt%) was attained in 48 h (batch runs) and 8 h of space-time (continuous runs). Such conditions were used to perform the transesterification reactions from palm kernel oil with simulated fusel oil rendering similar results. The kinematic viscosities at 40 °C confirmed the high conversion by modifying the initial palm kernel oil viscosity from 30.13 mm2 s−1 to values ranging from 3 to 6 mm2 s−1. The viscosity index was 149.22 ± 2.11 and the oxidative stability was 23.85 ± 1.65 min. Also, the biocatalyst was found to be stable revealing half-life time (t 1/2) of about 38 days. Graphical abstract Image 1 Highlights • Discontinuous and continuous enzymatic transesterification was performed. • Lipase from Burkholderia cepacia immobilized on SiO 2 -HEC was used as biocatalyst. • Simulated fusel oil and isoamyl alcohol were used as acyl acceptors to transesterification reaction. • High yields and productivities were attained in the packed bed reactor. • Ester biolubricants showed satisfactory values for viscosity index and oxidation stability. [ABSTRACT FROM AUTHOR]

Abstract Few studies have delved into the effect of low molecular alcohol on foam stability. This study firstly investigated the improvement in adsorption behavior and viscoelastic behavior at the surface of the APG solution in the presence of isoamyl alcohol, and then we observed that isoamyl alcohol could hinder the liquid drainage and retard the foam rupture by introducing the stabilization capacity (i.e., reducing the surface tension, increasing the surface viscoelasticity, creating the H-bond and providing the disjoining pressure). Afterwards, the addition of isoamyl alcohol can efficiently diminish the defoaming effect of crude oil and impose a considerable oil resistant in foam system. Finally, the flooding experiments were conducted in the tight formation. The results indicate that APG-alcohol foam presents a fine texture and reaches the maximum apparent viscosity at the transition foam quality of 0.67. As presented in the NMR experiment, APG-alcohol foam can efficiently displace the oil in pores with various sizes and substantially promote the EOR to 30.35%. Graphical abstract Image 1 Highlights • A novel foaming agents stabilized by isoamyl alcohol. • APG-alcohol foam shows surface adsorption and viscoelasticity enhancements. • Addition of alcohol can diminish the defoaming effect of crude oil. • APG-alcohol foam displaces the oil in whole pores of tight formation. [ABSTRACT FROM AUTHOR]

The kinetics of the esterification between benzoic acid and isoamyl alcohol has been studied using p‐toluenesulphonic acid as a catalyst. The conversion of the benzoic acid was determined by following the concentration of water measured with a Karl Fischer titrator. The effects of the reaction temperature, catalyst concentration, and initial acid to alcohol molar ratio on reaction kinetics have been examined. A five‐step assumption was proposed to describe the reaction mechanism for the formation of isoamyl benzoate. And the kinetic model derived from the proposed mechanism can fit well with experimental kinetic data of the esterification, which indicates that the proposed mechanism is reasonable. The nonideality of the liquid reaction mixture has been considered and the activity coefficients of all components were estimated by the UNIFAC model. The reaction rate constants from 353.15 K to 383.15 K have been determined through the least square method. Meanwhile the activation energy and the standard enthalpy change of reaction in the presence of p‐toluenesulphonic acid were calculated to be 50.45 kJ/mol and −3.75 kJ/mol respectively. A five‐step assumption was proposed to describe the reaction mechanism for the formation of isoamyl benzoate. Meanwhile the kinetic model derived from the proposed mechanism can fit well with experimental kinetic data of the esterification, which indicates that the proposed mechanism is reasonable. [ABSTRACT FROM AUTHOR]

The present work seeks to define the “green character” of red wines and characterise the groups of molecules potentially involved in that perception. Fifty-four wines were screened by wine experts for different levels of green character. Six different phenolic fractions were obtained by liquid chromatography (LC) and further submitted to sensory and chemical characterisation. The volatile fraction was screened by semipreparative LC, Gas Chromatography-Olfactometry (GC-O) and quantitative analysis. The green character was linked to vegetal aroma, astringency, green and dry tannins according to experts of the Somontano region. Non-volatile fractions containing tannins with mean degree of polymerisation of ten and smaller anthocyanin-derivative pigments (