Organic Compounds Research Articles

Acid Resistance Engineering of Endoglucanase for the Degradation of Wine Lees.

Wine lees is a low value biomass resource rich in cellulose, with great potential for producing organic fertilizers and chemicals. However, the high acidity of wine lees limits the catalytic efficiency of the conversion tool endoglucanase. Here, we expressed endoglucanase tCel5A from Trichoderma reesei in Pichia pastoris, and the combination of promoter AOX1 and signal peptide SUC2 resulted in a highly active expression of 4632.81 U/mg. Subsequently, the catalytic center design and surface charge modification strategy resulted in mutants T88H/W255H and S45D/T55D/T59D exhibiting catalytic activity twice and three times higher than WT at pH 3.0, respectively. Finally, when the solid-liquid ratio was 1:15 (w/v), the degradation rate of wine lees was nearly double that of WT. The degradation products contained a variety of industrial and pharmaceutical raw components, including the antioxidant and anticonvulsant isopiperolein B. This study accelerates the green and sustainable management of wine lees.

Characteristics of oxygenated volatile organic compounds in Zurich, Switzerland: Sources, composition, and implication for secondary aerosol formation

Volatile organic compounds (VOCs) are of vital importance in the formation of secondary organic aerosol (SOA). Understanding SOA formation remains challenging, requiring further investigation of both oxygenated VOCs (OVOCs) and SOA composition with novel measurement techniques. In this work, we deployed a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) to measure VOCs and their oxidation products in urban Zurich in summer 2016. The positive matrix factorization (PMF) source apportionment method identified five sources, including two primary sources (traffic and local), and three OVOC sources associated with different oxidation processes in the atmosphere. Together with the deployment of an extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF-MS), this enabled a detailed understanding of the SOA components which were dominated by biogenic SOA and distinguished by daytime and nighttime chemistry. The combination of the two instruments provided new insights in the understanding of atmospheric processes by comparison of molecular-level secondary components between gas phase and particle phase. In the gas phase, two OVOC factors (32.1% and 16.7%) showed strong influence from the oxidation of aromatic compounds, exhibiting low atomic H to C ratios, and were distinguished by daytime and night-time chemistry. The third OVOC factor (19.3%) was characterized by strong biogenic influence. Similar temporal variations were found for the gas and aerosol phase, indicating co-evolution of OVOCs and SOA in summer. Besides, comparisons of OVOC compounds and SOA composition exhibited similar H to C ratio distributions for both the gas phase and particle phase.

Cleaning the Air With Microbes and Magnetic Fields

Microbes are tiny organisms, but when it comes to eating, they have powerful appetites. They even have a taste for harmful stuff. While eating harmful substances, they can help us clean the environment. We can use these hungry microbes to get rid of man-made contaminants present in the air we breathe, such as the pollutants called volatile organic compounds released into the air by certain industries. We can give microbes a boost with a magnetic field, stimulating their appetite and their growth, and thus making them even greater cleaners. Such magnetic fields have lots of helpful applications in our daily lives.

Spatial distribution studies on sedimentary organic matter along the shoreline of Arabian Sea: insights from Kollam, Southwest Coast, India.

The present study was aimed at investigating the source, quality, and quantity of organic matter and labile fraction of biochemical constituents in the surficial sediments of Arabian Sea Shoreline at Kollam, India, which gives an input into the processes associated with the subsurface geochemistry pattern. About 15 surface sediment samples were collected from the five beaches for this study during January 2021. The samples were analyzed for CHN, total organic carbon (TOC), and labile fraction such as carbohydrates (CHO), proteins (PRO), and lipids (LIP). The TOC/TN ratio revealed that the source organic matter (OM) in the samples was primarily of marine origin and autochthonous, except TM3 at Thirumullavaram. Thirumullavaram is a sheltered beach, and it has low hydrodynamic process. The high organic matter content in TM3 (13.9) may be the originated from the terrestrial input. The hierarchical cluster analysis revealed that TM3 indicate that unique character to other stations. Principal component analysis revealed that three components accounted for 78% of the total variance. PC1 variance was associated with carbon-based organic compounds. PC2 was predominantly influenced by CHO and LOM, suggesting that PC2 may encompass variability associated with these nutritional profiles. PC3 was influenced by LIP and LIP/CHO, showing it may be a lipid-related component. The PRO to CHO ratio is < 1, exhibiting old aged organic matter deposited in sediments and the meso-oligotrophic status. The LIP to CHO ratio, recorded as < 1, exhibits the poor quality of energetic (food) OM in sediments. The sediment samples exhibit the following trend CHO > PRO > LIP.

Antibacterial activity of the biogenic volatile organic compounds from three species of bamboo

Plant biogenic volatile organic compounds (BVOCs) possess ecological functions in antimicrobial benefits and air purification. The objectives of the study were to determine the differences in antimicrobial capacity of bamboo forests at different sampling sites. Three common bamboo species—Phyllostachys edulis, Bambusa emeiensis, and Phyllostachys violascens—were selected to determinate the antimicrobial activity of bamboo forests as well as under ex vivo conditions. Natural sedimentation method was used to determine the microbe counts in bamboo forests, and the microbe counts in grassland in the same area was measured as control treatment. The results showed that except for the P. violascens in Ya’an, the airborne microbial content of the sampling sites in bamboo forests was significantly lower relative to that of grassland in the same area, and inhibition rate reached 74.14% in the P. violascens forest in Dujiangyan. P. edulis forest and P. violascens forest in Ya'an had significantly lower inhibition rates than the other sampling sites, and there was no significant difference in the inhibition rates among the rest of the bamboo forest. The bacterial inhibition rate of bamboo leaves under ex vivo conditions varied with bamboo species and bacterial strains, with higher antibacterial activity against Gram-negative bacteria overall. Escherichia coli was sensitive to B. emeiensis leaves, while Staphylococcus aureus and Bacillus subtilis were sensitive to P. violascens leaves. Moreover, Candida albicans, S. cremoris, and Shigella Castellani were sensitive to P. edulis leaves. An analysis of the BVOCs composition from P. edulis collected in Changning by SPME-GC/MS revealed that the relative content of ocimene was obviously higher than other components. This study showed that P. edulis BVOCs have strong inhibitory ability to the tested microorganisms, and its main constituent, ocimene, has health benefit. P. edulis has the potential to become a forest recreation bamboo species.

Gem-Difluorovinyl and trifluorovinyl Michael acceptors in the synthesis of α,β-unsaturated fluorinated and nonfluorinated amides

The incorporation of fluorine atoms within the structure of organic compounds is known to exert a significant impact on their electronic properties, thereby modulating their reactivity in diverse chemical transformations. In the context of our investigation, we observed a striking illustration of this phenomenon. A Michael addition involving gem-difluorovinyl and trifluorovinyl acceptors was successfully achieved, demonstrating high stereoselectivity. This selectivity was further elucidated through theoretical calculations. Using this methodology, a series of new α,β-unsaturated amides, both fluorinated and nonfluorinated, were synthesized.

Recent Advances in Perovskite Nanomaterials for Sensing Applications

Abstract Perovskite-structured materials have been extensively studied for sensing applications on account of their good thermal stability and 3-4 eV bandgap. They have been utilized to detect traces of O2, NO, CO, NO2, CO2, H2O, CH4, H2 and similar smaller gas molecules such as C2H5OH etc. In addition, other sensing applications are optical sensing, I-V fluctuations, strain sensors, electromechanical sensors, sensing of metal ions, etc. Perovskite-structured halides are reported for sensing of metal ions, toxic gases, Volatile Organic Compounds (VOCs), detection of fungicides, pesticides, explosives, cellular imaging, radiation detection and humidity and temperature sensing.

Evaluation of flavor characteristics in Chinese wheat flour paste using electronic-nose, electronic-tongue, and headspace-gas chromatography-ion mobility spectrometry at different fermentation stages.

Wheat flour paste is a typical Chinese fermented food, valued for its distinct flavors and health benefits. However, evidence regarding volatile organic compounds (VOCs) in Chinese wheat flour paste is limited. This study aims to examine the effect of fermentation on the VOCs and their physicochemical properties. Chinese wheat flour paste fermented at different stages was characterized using headspace gas chromatography ion-mobility spectrometry (HS-GC-IMS) with an electronic nose (E-nose) and an electronic tongue (E-tongue). The results revealed that around 76 VOCs were found in Chinese wheat flour paste from all stages of fermentation. These included esters, alcohols, aldehydes, ketones, acids, furans, and pyrazines. The E-tongue and E-nose analyses also showed high responses for saltiness, umami, WIW, and W5S. The fermentation process changed the color of the wheat flour paste, and the taste, and smell parameters. Principal component analysis (PCA) showed that taste parameters were positively associated with the volatile flavor profile detected in wheat flour paste. Partial least squares discriminant analysis also identified 28 VOCs as distinct flavor metabolites across fermentation stages. At the 'after ripening' (AR) and 'sterilization' (S) stages of wheat flour paste fermentation there were strong umami and salty flavors, with minimal sour and sweet notes in comparison with the other stages. These stages were characterized by elevated terpene concentrations, inorganic sulfides, and key flavor enhancers such as 2-hexanol and propyl sulfide. Headspace gas chromatography ion-mobility spectrometry and E-nose technologies are recommended for a more precise assessment of volatile changes during fermentation. The findings indicate that the 'sterilization' stage of wheat flour paste fermentation is optimal for achieving the required flavor profile. © 2024 Society of Chemical Industry.

Amplification of the Surface-Enhanced Raman Scattering Signal from a Monolayer of Organic Molecules in Sandwich Structures Containing Plasmonic Silver Nanoplates

Amplification of the Surface-Enhanced Raman Scattering Signal from a Monolayer of Organic Molecules in Sandwich Structures Containing Plasmonic Silver Nanoplates

Classical Batch Distillation of Anaerobic Digestate to Isolate Ammonium Bicarbonate: Membrane Not Necessary!

The excessive mineralization of organic molecules during anaerobic fermentation increases the availability of nitrogen and carbon. For this reason, the development of downstream processing technologies is required to better manage ammonia and carbon dioxide emissions during the storage and land application of the resulting soil organic amendment. The present work investigated classical distillation as a technology for valorizing ammoniacal nitrogen (NH4+-N) in anaerobic digestate. The results implied that the direct isolation of ammonium bicarbonate (NH4HCO3) was possible when applying the reactive distillation to the food waste digestate (FWD) with a high content of NH4+-N, while the addition of antifoam to the agrowaste digestate (AWD) was necessary to be able to produce an aqueous solution of NH4HCO3 as the distillate. The reason was that the extraction of NH4HCO3 from the AWD required a higher temperature (&gt;95 °C) and duration (i.e., steady state in batch operation) than the recovery of the inorganic fertilizer from the FWD. The titration method, when applied to the depleted digestate, offered the quickest way of monitoring the reactive distillation because the buffer capacity of the distillate was much higher. The isolation of NH4HCO3 from the FWD was attained in a transient mode at a temperature below 90 °C (i.e., while heating up to reach the desired distillation temperature or cooling down once the batch distillation was finished). For the operating conditions to be regarded as techno-economically feasible, they should be attained in the anaerobic digestion plant by integrating the heat harvested from the engines, which convert the biogas into electricity.

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The diversity of water pH values is a key factor that restricts the practical application of photocatalytic water purification. The construction of liquid (water)–liquid (oil)–solid (semiconductor) (L–L–S) triphase interface microenvironment makes the organic molecule adsorption pH independent and prevents the semiconductor from being corroded by strong acidic/alkaline solutions, leading to a stable and efficient photocatalytic reaction over a wide pH range (1–14). These findings reveal a promising path for the development of high‐performance catalysis systems applicable in complex water environments. More details are discussed in the article by Feng et al. on pages 3349—3354. image

Electron-Deficient Organic Molecules Based on B←N Unit: A N-Type Room-Temperature Chemiresistive Sensors with Moisture Resistance.

Organic molecules with tailorable chemical structures, high stability, and solution processability have great potential in the sensing field. Compared with p-type organic small molecules (OSMs), the electron-dominated n-type analogs show superior conductivity when exposed to reducing gases, which can achieve outstanding sensor signal-to-noise ratios. However, inadequate humidity resistance at room temperature hinders the development of such molecules. Herein, an A-D-π-D-A molecular design strategy is proposed based on electron-deficient B←N units, which results in effective intramolecular charge transport and sensitive responses by extending the π-conjugation bridge. As a result, the ST-2BP with A-D-π-D-A configuration shows a prominent sensitivity of 787 (Ra/Rg) in 20ppm NH3 at room temperature and an almost initial and stable response under different relative humidity conditions, which is the highest among currently reported OSM sensors. Supported by theoretical calculations and in situ FTIR spectra, it is revealed that B←N units, which function as the active centers mediate the specific ammonia adsorption. This study provides a new understanding of the design of high-performance room temperature gas sensing materials by decorating B←N units.

A biocompatible fluorescent probe for endogenous hydrogen sulfide detection and imaging.

Hydrogen sulfide (H2S) acts as a messenger molecule and can mediate a variety of physiological functions. Conventional methods are seldom used to detect endogenous H2S and present some difficulties in selective and accurate detection. Reaction-based recognition of endogenous H2S by organic small molecule probes with good specificity and biocompatibility. To address this challenge, we developed a novel H2S fluorescent probe 4-(2-(6-hydroxy-2-naphthyl) ethyl)-1-methylpyridinium (DSNP) that triggers a thiolysis reaction through a strong electron withdrawing group, releasing a fluorescent molecule. The simple probe DSNP not only have good selectivity, large Stokes shifts and biocompatibility, but also demonstrated a detection limit as low as 28.4 nM and reaction times as quick as 30 minutes. Moreover, it has been successfully applied to imaging intracellular H2S in myeloma cells and zebrafish. This study opens new insights to help push this probe forward for its applicability for detailed H2S localization studies in osteosarcoma.

Evaluation of wood coating performance and volatile organic compounds

The aim of this study was to evaluate the environment-performance relationship of surface coating applications on data obtained by measuring the emission rates of volatile organic compounds in polyurethane and water-based varnishes. For this purpose, polyurethane and water-based varnishes from five different companies were applied to the test samples of Entandrophragma cylindricum (sapele) and Piptadeniastrum africanum (dabema), both widely used in the production of urban furniture. Volatile organic compound, hardness and adhesion strength were measured during application. When evaluated in terms of performance, polyurethane varnishes showed superior hardness, while water-based varnishes demonstrated better adhesion after the UV test. The hardness values of polyurethane varnishes before and after the UV aging test were 15,9 s and 79,403 s, respectively, while forwater-based varnishes were , the values were 114,92 s and 75,406 s. The adhesion values of water-based varnishes were 2,885 MPa and 1,18 MPa before and after the UV aging test, and for polyurethane varnishes 3,13 MPa and 1,05 MPa for. When the environment-oriented results were evaluated, the ; emission values of volatile organic compounds in polyurethane varnish applications were found to be significantly higher than those in in water-based varnishes applications. While the total emission rate of volatile organic compounds detected in polyurethane varnishes was 53,63 mg/Nm3, while only one brand of water-based varnishes showed a measurable emission value, recorded at 0,0057 mg/Nm3. The volatile organic compounds emission values of other water-based varnishes were below the device detection limit (&lt;0,0035 mg/Nm3), and therefore could not be measured.

Effect of intercropping apple trees with basil (Ocimum basilicum) or French marigold (Tagetes patula) on the rosy apple aphid regulation (Dysaphis plantaginea) and the abundance of its natural enemies.

In a global context of pesticide reduction, the sustainable management of aphids is a major challenge in maintaining economically viable fruit production. Intercropping with companion plants (CPs) that emit volatile organic compounds (VOCs) with repellent or attractive properties could be successful in the laboratory. Still, their effects on the orchard have been little documented. We tested in 2018 and 2019 the hypotheses that the introduction of basil or French marigold, decreases the populations of Dysaphis plantaginea Passerini, the rosy apple aphid (RAA) and increases the abundance of its natural enemies (NEs) in an apple orchard in the south of France. Laboratory tests confirmed that both CPs altered RAA reproduction performance. In orchards, they attracted more NEs around the pots and at some dates in the aphid colonies near the pots in both years (apart from basil in 2019), without a significant reduction in aphid populations in 2018. In contrast, in 2019, the number and spatial expansion of aphid colonies were significantly lower, close to basil. Further investigation is needed to disentangle the mechanisms explaining the observed effects (e.g., repellent action in autumn, etc.) but the results highlight the potential of CPs to control aphids in orchards and contribute to agroecological production of apple. Thus, this study shows the potential of CPs in a strategy combining aphid repellency and NEs attraction to control aphids in orchards, provided that CP installation lasts over several consecutive years. © 2024 Society of Chemical Industry.

Phthalate esters in baltic lagoons: Spatial distribution, ecological risks, and novel insights into their fate using transcriptomics.

Plasticizers such as phthalate esters (PAEs) are organic compounds widely used in various consumer and industrial products, raising strong environmental concerns due to their pervasive presence and potential adverse effects. Lagoon ecosystems are particularly vulnerable to PAE pollution as they are semi-enclosed and receive high loads of organic materials. The present study investigates the distribution of seven common PAEs in three large European lagoons (Curonian, Vistula and Szczecin) in the southern Baltic Sea. The concentration levels of PAEs in the water column, encompassing both the dissolved and particulate-bound phases, and in sediments were assessed to elucidate distribution patterns and potential ecological risks within these lagoon ecosystems. The average concentration of total PAEs in the water column ranged from 0.03 to 1.45 μg L-1, whereas sediment concentration varied from 0.008 to 1.06 μg g-1, levels comparable to or lower than those found in other European coastal areas. Distribution patterns of PAEs in sediment showed notable similarity across all three lagoons, whereas variations were observed in the water column. Notably, di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DOP) and dimethyl phthalate (DMP) emerged as the most concerning congeners in studied lagoons, all of which pose a moderate risk to aquatic organisms. This study applied shotgun transcriptomic analysis to field samples, revealing active microbial communities involved in PAEs degradation in the Baltic lagoons for the first time. The degradation of phthalic acid (PA) into intermediate compounds such as protocatechuate was not identified as a rate-limiting step in the studied environment. The degradation activity was primarily localized in the sediment layers, with Gram-negative bacteria playing a major role, while Gram-positive bacteria appeared incapable of degrading PA. These findings provide valuable insights into the distribution and transformation mechanisms of PAEs in estuarine environments.

Development of a new breath collection method for analyzing volatile organic compounds from intubated mouse models

Abstract A new pre-clinical method for capturing breath samples from intubated mice is presented. This method significantly reduces background levels, allowing more accurate measurements of VOCs originating from the breath (“on-breath”) as opposed to background contamination. The method was developed by integrating industry-standard volatile-capturing sorbent tubes with respiratory mechanics measurement equipment (flexiVent®), resulting in a mouse breath sample that can be transported and analyzed by TD-GC-MS and other central lab technologies. Using the methodology, the discrimination between on-breath VOCs from background compounds provides a cleaner dataset, which can accelerate the validation of VOCs identified from mouse models and their translation to clinical trials. Three metrics were developed to identify on-breath VOCs, with 22 identified using Type 1 (50% of the breath samples exceeding three standard deviations above the mean signal of the system blanks), 34 with Type 2 (p-value ≤ 0.05 between paired breath and blank samples), and 61 with Type 3 (ROC-AUC value ≥ 0.8 to differentiate between breath and blank samples). The number of compounds seen at elevated levels on mouse breath was quantified and compared to the levels seen on human breath samples to compare methodologies.

Analysis of Microheterogeneous Glutelin Subunits and Highly Efficient Identification of Selenylation Peptides by In-Gel Proteolysis: Focus on Se-Enriched Rice.

Selenylation of cysteine and methionine thiols through selenate supplements increases the content of selenium-containing amino acids in various agricultural products. This modification results in numerous biological and health benefits. Despite their critical roles in human physiology, methods for high-coverage and efficient identification of selenylation peptides are limited. This study systematically developed a mass spectrometric method to identify selenylation peptides combined with in-gel trypsin proteolysis. In-gel proteolysis identified the two well-separated bands containing rice glutelin. We identified 11 rice glutelin subunits along with 42 selenylation peptides from the glutelin acidic subunits and 30 selenylation peptides from the glutelin basic subunits with high confidence. A comprehensive evaluation disclosed the mapping of selenium-containing rice glutelin subunits. Additionally, the selenylation modification of peptides coexisted with oxidation and iodoacetamide (IAM) alkylation. Moreover, the multidimensional MS criteria validated the results, while spectral statistics revealed the veritable Se/S substitution degree in Se-enriched rice. These findings collectively demonstrated the presence of numerous selenation sites in microheterogeneous glutelin subunits, thereby enhancing our understanding of the seleno-peptidomics of rice proteins. As significant bioactive organic compounds, the identified peptides in this study are promising candidates for a variety of bioactivities, including neuroprotective, anti-inflammatory, antioxidant, hepatoprotective, and immunomodulatory effects.

Study of Students' Difficulties and Conceptual Understanding of the Qualitative and Quantitative Analysis of Organic Compound Elements

The study examines the learning difficulties and understanding of concepts faced by 28 chemistry students in organic compound element analysis courses using the RADEC learning model. The results showed a moderate increase in understanding. Still, several factors contributed to the low understanding, such as 28% of students reporting difficulty with Kjeldahl material, 24% with Dumas topics, 5% with Lassaigne destruction topics, 9% with Kjeldahl and Dumas topics, and 5% with digestion, distillation, and titration. Additionally, 24% of students did not understand the meaning of the questions, the lecture material's delivery, and the writing of reaction equations. Lack of preparation, such as reading before lectures, also contributed to low understanding.

Kinetic Modeling in Temperature-Modulated Semiconductor Gas Sensor Utilizing Eley-Rideal Mechanism and Its Application in Discriminative Detection of VOCs.

This study presents a comprehensive kinetic investigation for describing the dynamic sensing process of semiconductor metal oxide (SMO)-based gas sensors, with a focus on the Eley-Rideal mechanism as a valid pathway. The modeling elucidates the direct interactions between volatile organic compounds (VOCs) and adsorbed oxygen on the material surface, providing insights into the temperature-dependent response characteristics of the sensor and addressing selectivity toward different VOCs fundamentally. By incorporating the effects of thermal modulation, the kinetic model was validated through theoretical fitting of experimental data obtained from a fabricated SnO2 nanoparticle gas sensor exposed to ethanol, n-propanol, toluene, and butanone at systematically varying operating temperatures. The results demonstrated that the model accurately captures response transient values, enabling a general framework for qualitatively discriminating specific gases based on their unique reaction kinetics. Furthermore, a machine learning procedure containing the above model and power laws of quantitative concentrations after identifying compounds was developed for the prediction of target VOCs. The qualitative accuracy was determined to be 99.4%, while quantifying with the mean absolute errors of 5.0, 7.5, 4.0, and 8.9 within the range of 25-200 ppm, respectively. The precise and straightforward strategy facilitates the response modeling of SMO-based gas sensors, offering a valuable platform for the designing model-driven algorithms applicable in gas analysis and monitoring.