Butyl acetate

Enantioseparation of ondansetron by countercurrent chromatography using sulfobutyl ether-beta-cyclodextrin as chiral selector.[Pubmed:33284511]

J Sep Sci. 2020 Dec 7.

Ondansetron, a highly selective 5-hydroxytryptamine 3 receptor antagonist, was successfully enantioseparated by recycling countercurrent chromatography using sulfobutyl ether-beta-cyclodextrin as chiral selector. Important factors for the enantioseparation were optimized, including different organic solvent, type of substituted beta-cyclodextrin, pH of aqueous phase, concentration of chiral selector and separation temperature. A biphasic solvent system composed of n-hexane: n-Butyl acetate: 0.1 mol L(-1) phosphate buffer solution pH 9.2 with 50 mmol L(-1) of sulfobutyl ether-beta-cyclodextrin (2.5:7.5:10, v/v/v) was selected. Under optimized separation conditions, 5 mg of ondansetron was enantioseparated using recycling countercurrent chromatography, yielding 1.2 mg and 1.5 mg of ondansetron enantiomers with 97.5% and 95.8% purity and the recovery reached 48-60%. This article is protected by copyright. All rights reserved.

Polyphenols, Antioxidant Activity and Volatile Compounds in Fermented Leaves of Medicinal Plant Rosebay Willowherb (Chamerion angustifolium (L.) Holub).[Pubmed:33271802]

Plants (Basel). 2020 Dec 1;9(12). pii: plants9121683.

At present, the consumption of medical plants and functional foods is growing in the whole world. Rosebay willowherb (Chamerionangustifolium (L.) Holub) is an important medicinal plant that has various pharmacological effects (antioxidant, anti-inflammatory, anticancer, and others), can improve the state of health and well-being, and reduce the risk of various diseases. The aim of this work was to investigate volatile compounds, polyphenols, and antioxidant activity in rosebay willowherb leaves fermented for 24 and 48 h in solid state fermentation under aerobic and anaerobic conditions. High-performance liquid chromatography (HPLC) for polyphenols and the spectrophotometric method for antioxidant activity determinations were used. To recognize and identify the leaves' fragrances, electronic nose (Alpha M.O.S) measurement technology was used. The results showed that the highest amounts of total polyphenols in dried matter were after 48 h aerobic solid state fermentation (SSF). Antioxidant activity was higher under 48 h SSF compared to the control. The most abundant flavoring compound groups were esters, terpenes, and aldehydes. In unfermented leaves, (z)-3-hexen-1-ol, acetate, hexyl acetate, and trans-hex-2-enyl acetate prevailed, characterized by fragrances of greenery, flowers, and fruits. The undesired esters group compounds, ethyl butyrate and Butyl acetate, with pungent odor, were detected after 48 h anaerobic SSF.

Comparative analysis of characteristic volatile compounds in Chinese traditional smoked chicken (specialty poultry products) from different regions by headspace-gas chromatography-ion mobility spectrometry.[Pubmed:33248636]

Poult Sci. 2020 Dec;99(12):7192-7201.

This article presents investigation of the flavor profile on 5 different regional Chinese smoked chicken samples using gas chromatography-ion mobility spectrometry analysis methods. Five batches of samples were obtained over the course of 6 mo. A total of 34 flavor substances were identified in the 5 smoked chicken samples, including 10 aldehydes, 7 alcohols, 4 ketones, 2 hydrocarbons, 3 heterocyclic compounds, 4 esters, 2 ethers, and 2 phenolic compounds. The whole spectral fingerprint visually displayed flavor differences and relations in 5 types of smoked chicken with local characteristics. Moreover, the orthogonal projections to latent structures discriminant analysis model revealed that these samples could be separately classified into 5 groups. Multivariate statistical analysis showed that 20 chemicals with higher Variable Importance for the Projection values were the key contributors to the differences of flavor in these 5 kinds of smoked chicken. N-nonanal, heptanal, n-nonanal, heptanal, furfurol, and hexanal were the main common flavor compounds in the 5 types of Chinese smoked chicken, whereas linalool, alpha-terpineol, 1,8-cineole, and anethole were the main characteristic flavor compounds of Goubangzi chicken (No. 1); gamma-butyrolactone, 2-acetylfuran, 2-methoxyphenol, 2-acetylpyrrole, and limonene were determined as the key flavor compounds of Liaocheng chicken (No. 2); the concentration of octanal and n-nonanal was higher in Tangqiao chicken (No. 3); Butyl acetate was the key contributor to the flavor compounds of Jinshan chicken (No. 4). 2-Heptanone and 2-pentylfuran had a high correlation with Zhuozishan chicken (No. 5). The different raw materials and ingredients used, especially the method of preparation and cultural differences, in different regions of the country in China were the main reasons leading to the similarities and differences of volatile compounds in the 5 kinds of Chinese traditional smoked chicken.

tert-Butyl Esters as Potential Reversible Chain Transfer Agents for Concurrent Cationic Vinyl-Addition and Ring-Opening Copolymerization of Vinyl Ethers and Oxiranes.[Pubmed:33200479]

Macromol Rapid Commun. 2020 Nov 16:e2000479.

tert-Butyl esters are demonstrated to function as chain transfer agents (CTAs) in the cationic copolymerization of vinyl ether (VE) and oxirane via concurrent vinyl-addition and ring-opening mechanisms. In the copolymerization of isopropyl VE and isobutylene oxide (IBO), the IBO-derived propagating species reacts with tert-Butyl acetate to generate a copolymer chain with an acetoxy group at the omega-end. This reaction liberates a tert-butyl cation; hence, a polymer chain with a tert-butyl group at the alpha-end is subsequently generated. Other tert-butyl esters also function as CTAs, and the substituent attached to the carbonyl group affects the chain transfer efficiency. In addition, ethyl acetate does not function as a CTA, which suggests the importance of the liberation of a tert-butyl cation for the chain transfer process. Chain transfer reactions by tert-butyl esters potentially occur reversibly through the reaction of the propagating cation with the ester group at the omega-end of another chain.

Eat1-Like Alcohol Acyl Transferases From Yeasts Have High Alcoholysis and Thiolysis Activity.[Pubmed:33193208]

Front Microbiol. 2020 Oct 29;11:579844.

Esters are important flavor and fragrance compounds that are present in many food and beverage products. Many of these esters are produced by yeasts and bacteria during fermentation. While ester production in yeasts through the alcohol acyl transferase reaction has been thoroughly investigated, ester production through alcoholysis has been completely neglected. Here, we further analyze the catalytic capacity of the yeast Eat1 enzyme and demonstrate that it also has alcoholysis and thiolysis activities. Eat1 can perform alcoholysis in an aqueous environment in vitro, accepting a wide range of alcohols (C2-C10) but only a small range of acyl donors (C2-C4). We show that alcoholysis occurs in vivo in several Crabtree negative yeast species but also in engineered Saccharomyces cerevisiae strains that overexpress Eat1 homologs. The alcoholysis activity of Eat1 was also used to upgrade ethyl esters to butyl esters in vivo by overexpressing Eat1 in Clostridium beijerinckii. Approximately 17 mM of Butyl acetate and 0.3 mM of butyl butyrate could be produced following our approach. Remarkably, the in vitro alcoholysis activity is 445 times higher than the previously described alcohol acyl transferase activity. Thus, alcoholysis is likely to affect the ester generation, both quantitatively and qualitatively, in food and beverage production processes. Moreover, mastering the alcoholysis activity of Eat1 may give rise to the production of novel food and beverage products.

Effects of Solvent Debinding on the Microstructure and Properties of 3D-Printed Alumina Ceramics.[Pubmed:33134708]

ACS Omega. 2020 Oct 16;5(42):27455-27462.

Solvents assist in the debinding of stereolithography-based 3D-printed alumina green bodies. The green bodies subsequently undergo thermal debinding and sintering to obtain alumina ceramics. In this study, several solvents were tested, including polyethylene glycol, oxalic acid, ammonium hydroxide, ethyl alcohol, methyl methacrylate, Butyl acetate, dimethyl carbonate, methanol, ethyl acetate, and sec-butyl alcohol. The tested solvents during the debinding process showed different effects on microstructure and properties of 3D-printed alumina ceramics due to the variable aspects of their solubility toward the binders. The microstructure of the samples changed significantly after green bodies underwent solvent debinding, thermal debinding, and sintering, leading to loose spongy structures, porous aggregates, and compact structures, respectively. Shrinkage, bulk density, and open porosity changed slightly due to the debinding function of different solvents. Polyethylene glycol-impregnated samples displayed the minimum shrinkage in length direction (5.3%). Ethyl alcohol-impregnated sample showed minimum shrinkage in width (4.8%) and height (11.5%) directions. Ammonium hydroxide-impregnated samples exhibited minimum bulk density (2.8 g/cm(3)) and maximum open porosity (28.3%). Dimethyl carbonate-impregnated samples presented minimum flexural strength (32.6 MPa), and oxalic acid-impregnated samples revealed maximum flexural strength (63.4 MPa). In sum, the as-obtained ceramics would be used as ceramic cores for hollow blades in aircraft engines due to their high open porosity and moderate flexural strength.

Complexation-association-extraction spectrophotometric determination of Pt cations based on a multi-reagent analytical system with I(-) anions and 2-[2-[4-[(2-cyanoethyl)methylamino]phenyl]vinyl]-1,3,3-trimethyl-3H-indolium cations.[Pubmed:33107867]

Anal Methods. 2020 Nov 28;12(44):5367-5379.

A new multi-reagent analytical system with 2-[2-[4-[(2-cyanoethyl)methylamino]phenyl]vinyl]-1,3,3-trimethyl-3H-indolium chloride (CPVTI), which is a styryl hemicyanine cationic dye with good photostability and a high molar absorption coefficient, as its core is first established and utilized successfully to determine the content of Pt ions via a spectrophotometric method. The process involves two treatment steps: adding CPVTI and I solutions to the Pt solution to be detected, and then using Butyl acetate for vortex liquid-liquid extraction. A Pt cation can be incorporated into the CPVTI cation with the help of an I(-) anion, initially converting the Pt cation into a [PtI6](2-) complex anion. After forming a [PtI6(2-).2CPVTI(+)](aq) ion associate in the aqueous phase, the Pt cation can be extracted selectively by Butyl acetate with maximum extraction efficiency, and exists as [PtI6(2-).2CPVTI(+)](org) in the extract phase. Via the formation of the iodo-complex of Pt and its ion associate with CPVTI, and the extraction with Butyl acetate, Pt is selectively partitioned into the Butyl acetate extractant in a step-by-step manner with good interference resistance. In the CPVTI-Pt-I analytical system, the charge state of CPVTI is retained by adjustment with H2SO4; the monovalent CPVTI(+) presents a strong spectrophotometric absorbance signal at 530 nm with long-term stability, which allows determination of the Pt content. The system shows a high molar absorption coefficient of 6.52 x 10(4) L mol(-1) cm(-1) at 530 nm, a lower limit of detection of 0.07 mg L(-1), and a good Sandell's sensitivity of 0.0030 mug cm(-2). Mechanistic analysis of the establishment of the system, concentration optimization, standard working curve, system sensitivity and stability, resistance against interference from diverse metal ions, and practical applications are investigated and discussed.

GC-MS analysis of underivatised new psychoactive substances in whole blood and urine.[Pubmed:33038866]

J Chromatogr B Analyt Technol Biomed Life Sci. 2020 Nov 1;1156:122308.

Herein a method was develop and validated for the detection and quantification of five new psychoactive substances (NPS) belonging to three categories: synthetic cathinones (mephedrone, 3,4-MDPV), opioids (AH-7921) and cannabinoids (JWH-018, AM-2201) by EI GC-MS. Target analytes were quantified in whole blood; in urine the same compounds plus methylone were detected. Liquid-liquid extraction by MTBE - Butyl acetate (1:1, v/v) in blood and Butyl acetate in urine was applied for the recovery of analytes, while no derivatization was necessary for their sensitive detection and quantification. The method showed good linearity for all analytes within a concentration range from 0.25 to 2 mug/mL for mephedrone, from 0.02 to 0.16 mug/mL for 3,4-MDPV and AH-7921 and from 0.005 to 0.04 mug/mL for JWH-018 and AM-2201. LOD ranged from 0.002 mug/mL (JWH-018 and AM-2201 in blood and urine), to 0.08 mug/mL (mephedrone in urine). LOQ in blood ranged from 0.005 mug/mL for JWH-018 and AM-2201 to 0.25 mug/mL for mephedrone. Accuracy was within acceptable limits with % bias ranging from +20% to -17.98% for intra-assay study and from +18.87% to -11.16% for inter-assay study. Precision was found to be between 2.60% and 17.17% (CV%) for intra-assay study and from 6.03% to 13.72% (CV%) for inter-assay study. An intra laboratory comparison provided proof of the method robustness. The developed method can be used for the reliable and fast quantification of five NPS in blood and the detection of six NPS in urine within the practice of a clinical or forensic toxicology laboratory.

Identification, characterization, and immobilization of a novel YbfF esterase from Halomonas elongata.[Pubmed:33031847]

Int J Biol Macromol. 2020 Dec 15;165(Pt A):1139-1148.

The YbfF esterase family, which has a bifurcated binding pocket for diverse ligands, could serve as excellent biocatalysts in industrial and biotechnological applications. Here, the identification, characterization, and immobilization of a novel YbfF esterase (YbfFHalomonas elongata) from Halomonas elongata DSM 2581 is reported. Biochemical characterization of YbfF was carried out using activity staining, chromatographic analysis, kinetic analysis, activity assay, acetic acid release, and pH-indicator-based hydrolysis. YbfFH.elongata displayed broad substrate specificity, including that for p-nitrophenyl esters, glucose pentaacetate, tert-Butyl acetate, and beta-lactam-containing compounds, with high efficiency. Based on a homology model of YbfFH.elongata, Trp(237) in the substrate-binding pocket, a critical residue for catalytic activity and substrate specificity was identified and characterized. Furthermore, crosslinked enzyme aggregates and nanoflower formation were explored to enhance the chemical stability and recyclability of YbfFH.elongata. The present study is the first report of a YbfF esterase from extremophiles, and explains its protein stability, catalytic activity, substrate specificities and diversities, kinetics, functional residues, amyloid formation, and immobilization.

Occupational symptoms due to exposure to volatile organic compounds among female Vietnamese nail salon workers in Danang city.[Pubmed:32949076]

J Occup Health. 2020 Jan;62(1):e12160.

OBJECTIVES: Nail workers are exposed to many hazardous chemicals. Despite many warnings about health problems among nail workers in other countries, data concerning exposure to chemical hazards among nail workers is still limited in Vietnam. In this study, we aimed to identify exposure to volatile organic compounds and their relationship with occupational symptoms among Vietnamese female nail salon workers. METHODS: A cross-sectional study was conducted in Danang, Vietnam, from January 2019 to September 2019. Total 42 personal passive samplers were collected to evaluate 12 substances from 21 nail workers (15 salons) twice a week. We chose one representative worker from each of the nine salons with less than six workers and two representative workers from each of the six salons with over five workers for personal sampling based on the principle of similar exposure groups. We interviewed a total of 100 nail workers in 15 salons and 100 office workers in offices adjacent to the salons to compare occupational symptoms among them. RESULTS: The commonly detected compounds in nail salons were acetone (97.6%), Butyl acetate (83.3%), and ethyl acetate and ethyl methacrylate (78%). The concentration of total target VOCs was related to the number of serviced customers, the concentration of CO2 , and general ventilation used. The subjective symptoms were significantly higher for the nail workers than for the comparison subjects, that is, headache, nausea, nose irritation, skin irritation, shortness of breath, and confusion. Among 100 nail workers, nose irritation was significantly higher for nail workers who were exposed to acetone at levels exceeding the Vietnam occupational exposure limit (VOEL) adjusted with the Brief-Scala model. CONCLUSIONS: Exposure to VOCs such as acetone in nail salons results in occupational symptoms among workers.

Characterization of a novel carboxylesterase belonging to family VIII hydrolyzing beta-lactam antibiotics from a compost metagenomic library.[Pubmed:32946943]

Int J Biol Macromol. 2020 Dec 1;164:4650-4661.

A novel esterase, EstCS3, was isolated from a metagenomic library constructed from a compost. The EstCS3, which consists of 409 amino acids with an anticipated molecular mass of 44 kDa, showed high amino acid sequence identities to predicted esterases, serine hydrolases and beta-lactamases from uncultured and cultured bacteria. Phylogenetic analysis suggested that EstCS3 belongs to family VIII of lipolytic enzymes. EstCS3 had catalytic Ser78 residue in the consensus tetrapeptide motif SXXK, which is characteristic of family VIII esterases. Two conserved YXX and W(H or K)XG motifs in an oxyanion hole of family VIII esterases were also present in EstCS3. EstCS3 demonstrated the highest activity toward p-nitrophenyl butyrate (C4) and was stable up to 70 degrees C with optimal activity at 55 degrees C. EstCS3 had optimal activity at pH 8 and maintained its stability within pH range of 7-10. EstCS3 had over 70% activity in the presence of 20% (v/v) methanol and DMSO and hydrolyzed sterically hindered tertiary alcohol esters of t-Butyl acetate and linalyl acetate. EstCS3 hydrolyzed ampicillin, cephalothin and cefepime. The properties of EstCS3, including moderate thermostability, stability against organic solvents and activity toward esters of tertiary alcohols, indicated that it has the potential to be used in industrial applications.

Metabolic and Process Engineering of Clostridium beijerinckii for Butyl Acetate Production in One Step.[Pubmed:32806108]

J Agric Food Chem. 2020 Sep 2;68(35):9475-9487.

n-Butyl acetate is an important food additive commonly produced via concentrated sulfuric acid catalysis or immobilized lipase catalysis of butanol and acetic acid. Compared with chemical methods, an enzymatic approach is more environmentally friendly; however, it incurs a higher cost due to lipase production. In vivo biosynthesis via metabolic engineering offers an alternative to produce n-Butyl acetate. This alternative combines substrate production (butanol and acetyl-coenzyme A (acetyl-CoA)), alcohol acyltransferase expression, and esterification reaction in one reactor. The alcohol acyltransferase gene ATF1 from Saccharomyces cerevisiae was introduced into Clostridium beijerinckii NCIMB 8052, enabling it to directly produce n-Butyl acetate from glucose without lipase addition. Extractants were compared and adapted to realize glucose fermentation with in situ n-Butyl acetate extraction. Finally, 5.57 g/L of Butyl acetate was produced from 38.2 g/L of glucose within 48 h, which is 665-fold higher than that reported previously. This demonstrated the potential of such a metabolic approach to produce n-Butyl acetate from biomass.

Peach volatile emission and attractiveness of different host plant volatiles blends to Cydia molesta in adjacent peach and pear orchards.[Pubmed:32788645]

Sci Rep. 2020 Aug 12;10(1):13658.

The oriental fruit moth (OFM), Cydia (= Grapholitha) molesta, is a highly damaging pest; peaches are its primary host, and pears serve as post-peach secondary hosts during the late season in China. We collected volatiles from detached peach shoots and fruits, and identified them with gas chromatography-mass spectrometry (GC-MS). Antennally active compounds were identified by gas chromatography-electroantennogram detection (GC-EAD), and these were further tested in the laboratory and field. We detected consistent electroantennographic activity was for ten compounds. Significantly more C. molesta females were caught with a mixture of female EAD-active compounds identified from the detached matured peach fruits (nonanal, Butyl acetate, 3-methylButyl acetate, hexyl acetate, (Z)-3-hexenyl acetate, linalool and farnesene) than other mixtures mimicking the volatile profile from detached matured fruits or shoots. We identified a new GC-EAD active mixture from intact peach shoots composed of nonanal, (Z)-3-hexenyl acetate, (E)-beta-ocimene, and 6-methyl-5-hepten-2-one. In the field test, the background odour of orchards could affect trap catches, and two peach-derived blends together with two previously known pear-derived blends were proven to be able to monitor the seasonal OFM population dispersal in adjacent orchards. These host plant blends will be effective for further designing candidate attractants for season-long C. molesta population dynamic monitoring.

Study of Room Temperature Ionic Liquids as Gas Sensing Materials in Quartz Crystal Microbalances.[Pubmed:32698487]

Sensors (Basel). 2020 Jul 20;20(14). pii: s20144026.

Twenty-eight quartz crystal microbalance (QCM) sensors coated with different sensing films were tested and analyzed in this work; twenty-three sensors were coated in different room temperature ionic liquids (RTILs) and five additional QCM sensors were coated with conventional films commonly used as stationary phases in gas chromatography. Four volatile organic compounds (VOCs), in gaseous phase-hexanol, Butyl acetate, 2-hexanone, and hexanoic acid-were measured. Two transducer mechanisms were used; resonant frequency shift and resistance shift of a QCM Mason equivalent circuit. The sensors were characterized by their sensitivity to the VOCs and their discrimination power of the four VOCs. The highest separation among VOCs was obtained when frequency and resistance information of both RTIL and conventional films was used, a sensor array composed by two RTILs (1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide and 1-hexyl-3-methylimidazolium hexafluorophosphate) and two conventional films (tricresyl phosphate and apiezon-L) was found to improve the Wilks lambda separation for the tested gases two orders of magnitude compared to the Wilks lambda using only a conventional films array.

In vitro growth of Colletotrichum gloeosporioides is affected by butyl acetate, a compound produced during the co-culture of Trichoderma sp. and Bacillus subtilis.[Pubmed:32656062]

3 Biotech. 2020 Aug;10(8):329.

The co-culture of plant beneficial microbes to stimulate the production of antimicrobial metabolites is gaining ground. Here, the inactivated Colletotrichum gloeosporioides mycelium was used to induce the biosynthesis of antifungal compounds in the co-culture systems of Trichoderma sp. and Bacillus subtilis. The hexanic extracts obtained from the co-culture systems were tested against C. gloeosporioides. Those that inhibited the phytopathogen growth were further fractionated by column and thin-layer chromatography and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Ethyl butanoate, Butyl acetate, acetic acid, 2-butoxyethanol, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, hexadecanoic acid, and octadecanoic acid were identified. Butyl acetate was the most abundant compound, and its application affected the morphology and mycelial development of C. gloeosporioides, thereby inhibiting the radial growth, reducing spore formation, and inducing soft colonies. We conclude that co-culturing Trichoderma sp. and B. subtilis promotes the production of novel diffusible organic compounds with an antifungal effect on C. gloeosporioides.