Volatile Products Research Articles

Investigation of controlled autoxidation of HVGO to produce carbon fibres precursors: Role of oxygen availability and mixing

Carbon fibre is an ultra-light, strong, and durable material that has growing demand in different industries. About 95 % of currently produced carbon fibre is PAN-based which is expensive. Considering the expense and accessibility, heavy vacuum gas oil (HVGO) shows significant promise. However, it necessitates appropriate pre-treatment to generate carbon fibre precursors. The present study examined the influence of oxygen availability and mixing on controlled autoxidation (oxidation with air) in order to establish a cost-effective and efficient pre-treatment technique for assessing the feasibility of generating carbon fibre precursors from the low-value heavy petroleum fraction HVGO. Experiments were performed while maintaining temperature (130–260 ℃), time (4–24 hours), and oxygen partial pressure (N2/air) maintaining bubbling with mixing, and also blowing without mixing. Blowing without mixing at 200 ℃ for 24 h showed the highest viscosity of 7959 cP (measured at 25 ℃), and HVGO heated at 240 ℃ in 8 h in the presence N2 resulted in a maximum 26 % increase in aromaticity. It was also noticed that there was an improvement in softening point (maximum 5.4 times), volatility, and heavy products, which are crucial properties of a carbon fibre precursor. Understanding from the current research can also be applied in the area of asphalt hardening, weathering, fouling, fuel transportation and storage stability, and sludge formation.

Online Monitoring of Volatile Products of Bioprocess Using Differential Ion Mobility─A Proof of Concept with 1-Undecene

Online Monitoring of Volatile Products of Bioprocess Using Differential Ion Mobility─A Proof of Concept with 1-Undecene

Evaluation of Antifungal Activity of Endophytic Bacillus spp. and Identification of Secondary Metabolites Produced Against the Phytopathogenic Fungi.

Endophytic bacteria serve as a rich source of diverse antimicrobial compounds. Recently, there has been a growing interest in utilizing endophytic Bacillus spp. as biological agents against phytogenic fungi, owing to their potential to produce a wide range of antimicrobial substances. The objective of this research was to investigate the protective abilities of 15 endophytic Bacillus spp. isolated from previous study from wheat plant, against the phytopathogenic fungi, Fusarium graminearum and Macrophomina phaseolina. A dual culture plate assay was conducted as a preliminary analysis, revealing that 7 out of 15 endophytic Bacillus spp. demonstrated inhibition against one or both of the phytopathogenic fungi used in this study. All seven endophytes were further assessed for the presence of diffusible antifungal metabolites. The cultures were grown in potato dextrose broth for 120h, and the cell-free supernatant was extracted and analyzed using the cup plate method. The methanolic extract yielded similar results to the dual culture plate analysis, except for WL2-15. Additionally, deformities in the mycelial structure were examined under the light microscope upon exposure to methanolic extract. Furthermore, the analysis and identification of metabolites were carried out via gas chromatography-mass spectrometry of methanolic extract from selected seven endophytic Bacillus spp. The chromatogram revealed the presence of some major peaks such as tridecanoic acid, methyl ester, hydroperoxide, 1-methylbutyl, 9-octadecenamide, (z)-, hexane-1,3,4-triol, 3,5-dimethyl- tetradecanoic acid. To the best of our knowledge, this is the first report of these biocontrol agents in endophytic Bacillus spp. Interestingly, volatile organic compound production was also seen in all the isolates against the phytopathogenic fungi.

Full‐Dimensional Analysis of Gaseous Products Within Li‐Ion Batteries by On‐Line GC‐BID/MS

AbstractThe gas release within Li‐ion batteries, particularly during cycling and storage, can result in rapid performance degradation and potential safety hazards. However, this area has not garnered sufficient attention until now, primarily because the gassing information collected by typical OEMS/DEMS is quite limited and even inaccurate. Herein, for the first time, a state‐of‐the‐art on‐line GC‐BID/MS to full‐dimensionally analyze the gassing behavior within both lab‐scale coin‐type cell (in situ mode) and industry‐scale pouch‐type cell (operando mode) is originally designed/constructed. Not limited to common permanent gases (e.g. H2, CO, etc.) detected by online GC‐BID, but also complicated/various (semi‐)volatile products are identified/quantified by online GC‐MS. Based on the real‐time evolution information of water, alcohols, aldehydes, ethers, esters, and hydrocarbons, the decomposition mechanisms of electrolyte on both graphite anode and/or LCO cathode sides is further supplemented/perfected. Moreover, at the level of the device, series derivative/crosstalk reactions induced by trapped/accumulated gaseous species are unveiled in practical pouch‐cell.

Relative expression of genes related to volatile organic compounds in non-climacteric and climacteric melons

Melon (Cucumis melo L.) is an important species in the cucurbit family with a large economic importance in the world. Two melon cultivars commercially important in Brazil are ‘Yellow’ and ‘Gaúcho’. In addition to their economic importance, these two cultivars display phenotypic differences in aroma, a major trait determining fruit quality. Volatile organic compounds (VOCs) impart the different aroma found in this fruit and their biosynthesis is associated with fatty acid and amino acid metabolism. Using RT-qPCR techniques, the expression of seven genes (CmLOX9, CmLOX18, CmBCAT1, CmArAT1, CmPDC1, CmADH1, and CmAAT1) was determined during ripening. The lipid pathway played a strong role in determining aroma composition in non-climacteric ‘Yellow’ melons. Most volatiles decreased during ripening, explaining the non-aromatic characteristic of this cultivar. In climacteric ‘Gaúcho’ melons, the amino acid pathway was the main one related to the biosynthesis of esters, which contribute to the aroma of this cultivar. Volatile products of the branched-chain amino acid pathway correlated with CmADH1 and CmAAT1 expression, demonstrating their role in volatile synthesis in this climacteric melon cultivar. In addition, CmPDC1 contributes to the formation of aldehydes at the beginning of this pathway.

Oxidation Mechanism and Toxicity Evolution of Linalool, a Typical Indoor Volatile Chemical Product.

Linalool, a high-reactivity volatile chemical product (VCP) commonly found in cleaning products and disinfectants, is increasingly recognized as an emerging contaminant, especially in indoor air. Understanding the gas-phase oxidation mechanism of linalool is crucial for assessing its impact on atmospheric chemistry and human health. Using quantum chemical calculations and computational toxicology simulations, we investigated the atmospheric transformation and toxicity evolution of linalool under low and high NO/HO2· levels, representing indoor and outdoor environments. Our findings reveal that linalool can undergo the novel mechanisms involving concerted peroxy (RO2·) and alkoxy radical (RO·) modulated autoxidation, particularly emphasizing the importance of cyclization reactions indoors. This expands the widely known RO2·-dominated H-shift-driven autoxidation and proposes a generalized autoxidation mechanism that leads to the formation of low-volatility secondary organic aerosol (SOA) precursors. Toxicological analysis shows that over half of transformation products (TPs) exhibited higher carcinogenicity and respiratory toxicity compared to linalool. We also propose time-dependent toxic effects of TPs to assess their long-term toxicity. Our results indicate that the strong indoor emission coupled with slow consumption rates lead to significant health risks under an indoor environment. The results highlight complex indoor air chemistry and health concerns regarding persistent toxic products during indoor cleaning, which involves the use of linalool or other VCPs.

Valorization of Wood Residues from Vegetation Suppression during Wind Energy Plant Implementation and Its Potential for Renewable Phenolic Compounds through Flash Pyrolysis: A Case Study in Northeast Brazil’s Semi-Arid Region

In the past few years, wind power has become a viable alternative in Brazil to diversify the energy mix and mitigate pollutant emissions from fossil fuels. Significant wind energy generation potential is inherent in the Brazilian Northeast state of Rio Grande do Norte, due to prevailing strong winds along the coastline and elevated regions. However, clean and renewable wind energy may lead to potential biodiversity impacts, including the removal of native vegetation during plant construction and operation. This case study explores the flash pyrolysis-based valorization of three commonly suppressed species, namely Cenostigma pyramidale (CP), Commiphora leptophloeos (CL), and Aspidosperma pyrifolium (AP), in a wind farm situated within the Mato Grande region of Rio Grande do Norte State. The study centers on determining their bioenergy-related properties and assessing their potential for producing phenolic-rich bio-oil. The investigation of three wood residues as potential sources of high-value chemicals, specifically phenolic compounds, was conducted using a micro-furnace type temperature programmable pyrolyzer combined with gas chromatography/mass spectrometry (Py–GC/MS setup). The range of higher heating values observed for three wood residues was 17.5–18.4 MJ kg−1, with the highest value attributed to AP wood residue. The bulk density ranged from 126.5 to 268.7 kg m−3, while ash content, volatile matter content, fixed carbon content, and lignin content were within the respective ranges of 0.8–2.9 wt.%, 78.5–89.6 wt.%, 2.6–9.5 wt.%, and 19.1–30.6 wt.%. Although the energy-related properties signifying the potential value of three wood residues as energy resources are evident, their applicability in the bioenergy sector can be expanded via pelleting or briquetting. Yields of phenolic compounds exceeding 40% from the volatile pyrolysis products of CL and AP wood residues at 500 °C make them favorable for phenolic-rich bio-oil production. The findings of this study endorse the utilization of wood residues resulting from vegetation suppression during the installation of wind energy plants as potential feedstocks for producing bioenergy and sustainable phenolic compounds. This presents a solution for addressing a regional environmental concern following the principles of green chemistry.

Light oxygenated volatile organic compound concentrations in an Eastern Mediterranean urban atmosphere rivalling those in megacities

Highly resolved measurements of primary and secondary oxygenated volatile organic compounds (OVOCs) by proton-transfer-reaction mass spectrometry (PTR-MS) and the AMOVOC sampler (Airborne Measurements Of VOC) were performed in Beirut, Lebanon, during the ECOCEM (Emissions and Chemistry of Organic Carbon in the East Mediterranean) experiments. The OVOC concentrations (0.15–7.0 ppb) rival those reported for international megacities like Paris, Tokyo, or São Paulo (0.3–6.5 ppb). This study highlights the seasonal variability of OVOCs, the potential role of background pollution on OVOC concentrations, traffic emissions of OVOCs, and the secondary production of OVOCs during both summer and winter.The primary and secondary OVOC fractions were estimated using two methods based on the night-time emission ratio and photochemical age. Our calculations coupled with a correlation analysis revealed the following: firstly, background concentrations contributed significantly, especially for longer-lived OVOCs, such as methanol and acetone (30%–80%). Secondly, secondary production in summer increased up to 60%, except for methanol and isoprene oxidation products, i.e., for methacrolein and methyl vinyl ketone. Thirdly, the secondary production in the Eastern Mediterranean persisted in winter, and finally, strong primary traffic emissions dominated the primary biogenic emissions.Finally, the emission ratios were used to evaluate the global anthropogenic emission inventories downscaled to Lebanon. Although limited to two individual non-lumped species (formaldehyde and acetone), the emission ratios compared well, within a factor of 2. However, the emissions of aldehydes and ketones from the CAMS, Edgar, and MACCITY inventories showed discrepancies of up to three orders of magnitude. This demonstrates a need for improved OVOC representation in emission inventories, considering the atmospheric relevance and abundance of OVOCs and their use in volatile chemical products.

Relationship between predicted in vivo and observed in vivo methane production from dairy cows fed a grass-silage based diet with barley, oats, or dehulled oats as a concentrate supplement

The objectives of this study were to compare predicted in vivo methane (CH4) values based on data from an in vitro gas production experiment with observed in vivo values measured by the GreenFeed system, and to investigate the effect of the diet fed to donor animals of rumen inoculum (RI) on predicted in vivo CH4 production. For this purpose, we conducted an in vivo experiment simultaneously with an in vitro gas production experiment. The in vivo experiment (previously published) was a 4 × 4 Latin square design including 16 Nordic Red dairy cows. Cows were fed 60% grass silage and 40% concentrate which consisted of either barley, oats with hulls (hulled oats), dehulled oats, or a 50:50 mixture of hulled and dehulled oats on dry matter basis. The in vitro experiment was a 2 × 4 factorial design replicated in 4 runs. The in vitro diets were incubated for 48 h in two types of RI and formulated according to the diets fed in vivo. The RI was obtained from cows fed either barley (two cows) or hulled oats (two cows) as concentrate in the in vivo experiment. A set of models were applied to the gas and CH4 data obtained from the in vitro system to predict in vivo total gas and CH4 production. For the comparison between predicted in vivo and observed in vivo CH4, two different mean retention times (MRT of 35 and 50 h) in the rumen were used for the predictions. In the in vitro experiment, incubation residues were determined for organic matter digestibility and volatile fatty acids at 48 h of incubation. Assuming a MRT of 35 h in the rumen resulted in a significant relationship (P = 0.04) between predicted in vivo and observed in vivo CH4 yield (g/kg dry matter) with an R-square of 0.91 and a root mean square error of 0.20. Ranking of the diets in terms of their CH4 production was consistent between the in vitro and in vivo experiment. There were no significant interactions between diet and RI for any of the investigated parameters (P = 0.40). Rumen inoculum did not affect organic matter digestibility or total volatile fatty acid production. In conclusion, there was a good agreement between predicted in vivo and observed in vivo CH4 values. In addition, the diet of RI donor animal did not influence the comparison of diets in terms of CH4 production.

Simultaneous optimizations of heavy metal immobilizations, products, temperature, and atmosphere dependency by acid pretreatment-assisted pyrolysis and gasification of hyperaccumulator (Pteris vittate L.) biomass

The safety and feasibility of directly treating hyperaccumulators with heat is constrained by the substantial presence of volatile heavy metals (HMs) within these plants. The combination of acid pretreatment and heat treatment holds potential for both energy recovery from hyperaccumulators and the transfer of their HMs to specific phases. This study aimed to reveal not only the pyrolysis and gasification kinetics and products of arsenic-hyperaccumulator (Pteris vittate L.) (PV) pretreated with HCl or H3PO4 but also the migration, distribution, and leaching of HMs in products and interaction between HMs and minerals. The HCl-pretreated PV exhibited similar decomposition behaviors and mechanisms to the control PV, with a gradual decrease in overall activation energy (Em). In contrast, H3PO4 changed the behaviors and increased Em. The relative yield of syngas and biochar rose with increased acid concentration. Given the pyrolysis and gasification-induced volatile products released at 550, 750, and 950 °C, HCl increased the relative yield of aromatic compounds and reduced the formation of ring-opening products compared with PV. Compared with HCl, H3PO4 increased the emissions of aromatic compounds and ketone. HCl promoted the loss of HMs, including accelerating their volatilization from the solid phase and increasing their leaching concentration from the biochar. HMs were mostly retained in the H3PO4-pretreated PV biochar with a low leachable rate, gradually decreasing with the rising temperature. The maximum energetic performance and HM immobilizations were optimized using artificial neural networks. This study revealed plausible reaction pathways and immobilization mechanisms, involving the interactions between minerals and HMs due to Cl or P introduced by the acid pretreatment. Overall, our findings provide new insights into the pyrolysis and gasification behavior of acid-pretreated hyperaccumulator. In particular, the H3PO4 pretreatment not only produced high-yield, high-quality bio-oil products with low HM content but also retained the HMs in the biochar.

Foliar urea applications to apple trees increase yeast assimilable nitrogen, amino acids, and flavor volatiles in fruit and hard cider

Volatile compounds are a crucial component of hard apple (Malus ✕domestica Borkh.) cider aroma, flavor, and consequent marketability. Amino acids are used by Saccharomyces cerevisiae yeast in the production of volatiles and their precursors. This study hypothesized that foliar applications of nitrogen to apple trees would elevate the concentration of amino acids in the fruit, thus increasing the concentration of sensorially distinguishable aromatic volatiles in cider. In this experiment, urea foliar fertilizer was applied to ‘Ellis Bitter’ and ‘Harry Masters Jersey’ apple trees to create Control (0 applications), Low (3 weekly applications), and High (5 weekly applications) treatments. Total leaf nitrogen increased with the number of foliar urea applications, demonstrating plant uptake. The total fruit yield and fruit efficiency (total harvested fruit mass relative to trunk cross-sectional area) did not differ among treatments within the same cultivar. Similarly, fruit maturity, size, total phenolics, pH, and soluble solids concentration did not differ among treatments. Yeast assimilable nitrogen (YAN) and amino acids in the juice increased with the number of foliar urea applications, as did fermentation rates. Relative to the Control, the High treatment had 130% greater YAN in ‘Ellis Bitter’ and 145% in ‘Harry Masters Jersey’. Over 90% of the YAN in all juice samples was composed of primary amino nitrogen (PAN), and the majority of the PAN among all treatments was asparagine. Ester and fatty acid content in hard ciders increased with the number of urea applications; however, higher alcohols showed a mixed relationship with the number of applications in the cultivar ‘Ellis Bitter’. Aroma and flavor differences among treatments were discernible by triangle discrimination test panelists; however, the specific sensory differences were not easily identifiable with untrained panelists. This study demonstrated that late season foliar urea applications to apples trees can increase juice YAN and aromatic compounds in finished cider.

Silencing an ATP-Dependent Caseinolytic Protease Proteolytic Subunit Gene Enhances the Resistance of Rice to Nilaparvata lugens.

The ATP-dependent caseinolytic protease (Clp) system has been reported to play an important role in plant growth, development, and defense against pathogens. However, whether the Clp system is involved in plant defense against herbivores remains largely unclear. We explore the role of the Clp system in rice defenses against brown planthopper (BPH) Nilaparvata lugens by combining chemical analysis, transcriptome, and molecular analyses, as well as insect bioassays. We found the expression of a rice Clp proteolytic subunit gene, OsClpP6, was suppressed by infestation of BPH gravid females and mechanical wounding. Silencing OsClpP6 enhanced the level of BPH-induced jasmonic acid (JA), JA-isoleucine (JA-Ile), and ABA, which in turn promoted the production of BPH-elicited rice volatiles and increased the resistance of rice to BPH. Field trials showed that silencing OsClpP6 decreased the population densities of BPH and WBPH. We also observed that silencing OsClpP6 decreased chlorophyll content in rice leaves at early developmental stages and impaired rice root growth and seed setting rate. These findings demonstrate that an OsClpP6-mediated Clp system in rice was involved in plant growth-defense trade-offs by affecting the biosynthesis of defense-related signaling molecules in chloroplasts. Moreover, rice plants, after recognizing BPH infestation, can enhance rice resistance to BPH by decreasing the Clp system activity. The work might provide a new way to breed rice varieties that are resistant to herbivores.

Physicochemical, thermodynamic, and kinetic controls on volatile products, bio-oils, and biochars of Lycium barbarum pyrolysis and their multi-objective optimization

The substantial stream of Lycium barbarum (LBL) residues presents an opportunity for the valorized generation of energy and products through their pyrolysis. This study aimed to quantify the pyrolytic bioenergy potential of LBL by assessing its physicochemical properties, pyrolysis performance, kinetics, thermodynamics, volatile products, bio-oils, and biochars. The LBL pyrolysis consisted of the three consecutive stages of dehydration, devolatilization, and charring or carbonization of the residuals. The main pyrolysis temperature varied between 125.00 and 700.00 °C. The kinetic and thermodynamic parameters of the LBL pyrolysis (0.1 < α < 0.9) were estimated via the Friedman method. Its activation energy ranged from 133.10 to 318.36 kJ/mol. Gases and functional groups identified included H2O, CO2, CH4, CO, CC, C-O, and C-OH. The primary pyrolytic outputs comprised ketones/alcohols, furans, acids, and N-containing compounds. Artificial neural networks were employed to jointly reconstruct and optimize the pyrolysis conditions. The simultaneously minimum gas emissions occurred at 677 and 1000 °C. The temperature dependence of pyrolytic biochar production was also characterized. The formation of pores was attributed to the increased pyrolysis temperature, increasing both the release of volatiles and the carbonization degree of activated carbon. This study provides both theoretical insights and practical guidance for the comprehensive utilization and effective management of Lycium barbarum residues.

Gas-to-Biochar Byproducts of Pyrolysis and Gasification of Star Anise Biomass

In a transition to a circular economy, second-generation biomass energy has come to the forefront. The present study is aimed at characterizing biochar and byproducts of the pyrolysis of star anise residue (ANI) in the N2 and CO2 atmospheres as well as the kinetics and optimal reaction mechanisms based on the Flynn–Wall–Ozawa and Coats-Redfern methods. The ANI pyrolysis involved three stages, with the first one (161.5–559.1°C) as the main phase. The activation energy was lower in the N2 atmosphere than in the CO2 atmosphere (179.44–190.17 kJ/mol). The primary volatile products generated during the ANI pyrolysis were small molecule products (H2O, CO2, CO, and CH4), organic acids, alcohols, and ketones. The atmosphere type exerted a minimal impact on the types of gases released, with the CO2 atmosphere increasing CO and CH4 emissions. The pyrolytic oil of ANI contained a variety of organic compounds, including alcohols, phenols, ketones, acids, sugars, and other nitrogen- and oxygen-containing cyclic compounds, with its predominant compounds being acids, esters, ketones, and sugars. The elevated temperature range of 300–700°C enhanced the charring degree of the ANI biochar. The biochar showed stronger aromaticity in the CO2 atmosphere but better granularity in the N2 atmosphere. This study introduced an innovative perspective by showcasing the potential of ANI as a promising biomass source for energy generation and underscored its abundance, sustainability, and applicability as a raw material in fragrance production. It also emphasized the significance of CO2-reuse technology as a means to mitigate CO2 emissions. The findings of this work offer a theoretical and practical basis for the comprehensive utilization and efficient disposal of star anise residues.

Functional analysis and comparative genomics of Rahnella perminowiae S11P1 and Variovorax sp. S12S4, two plant growth-promoting rhizobacteria isolated from Crocus sativus L. (saffron) rhizosphere.

Rahnella perminowiae S11P1 and Variovorax sp. S12S4 are two plant growth-promoting rhizobacteria that were previously isolated from the rhizosphere of Crocus sativus L. (saffron), and have demonstrated interesting PGP activities and promising results when used as inoculants in field trials. To further elucidate the molecular mechanisms underlying their beneficial effects on plant growth, comprehensive genome mining of S11P1 and S12S4 and comparative genomic analysis with closely related strains were conducted. Functional annotation of the two strains predicted a large number of genes involved in auxin and siderophore production, nitrogen fixation, sulfur metabolism, organic acid biosynthesis, pyrroloquinoline quinone production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, volatile organic compounds production, and polyamine biosynthesis. In addition, numerous genes implicated in plant-bacteria interactions, such as those involved in chemotaxis and quorum sensing, were predicted. Moreover, the two strains carried genes involved in bacterial fitness under abiotic stress conditions. Comparative genomic analysis revealed an open pan-genomic structure for the two strains. COG annotation showed that higher fractions of core and accessory genes were involved in the metabolism and transport of carbohydrates and amino acids, suggesting the metabolic versatility of the two strains as effective rhizosphere colonizers. Furthermore, this study reports the first comparison of Multilocus sequence analysis (MLSA) and core-based phylogenies of the Rahnella and Variovorax genera. The present study unveils the molecular mechanisms underlying plant growth promotion and biocontrol activity of S11P1 and S12S4, and provides a basis for their further biotechnological application in agriculture.

Unexpected high yield of acrolein underlies the importance of the hydrogen-abstraction mechanism in photooxidation of allyl methyl sulfide (AMS).

This work explores theoretically the gas phase oxidation of allyl methyl sulfide (AMS, H2CCHCH2SCH3) initiated by •OH radicals, focusing on the H-abstraction pathway at the M06-2X-D3/aug-cc-pVTZ and MN15/aug-cc-pVTZ levels of theory (m06Tz and mn15Tz). The formation of a prereactive complex (PRC) is involved in H-abstraction processes with two potential directions of approach for the OH radical, denoted as “α” and “β”. The PRCs, demonstrate increased reactivity, primarily due to the interaction between the sulfur atoms and the hydroxyl hydrogen. A scheme for the H-abstraction mechanism that supports the experimentally identified products and predicts the formation of some S-containing low volatility products is proposed. The comparison of the potential energy surface (PES) between the double bond addition and H-abstraction paths in the AMS molecule shows that at the m06Tz level of theory, the H-abstraction on C3 and the addition to C1 have nearly the same profile of energy, while at the mn15Tz level, the minimum energy channel is the addition to C1. The theoretical rate coefficient for each reaction channel was calculated, considering the formation of a PRC prior to reaching the transition state of each channel and assuming thermal equilibrium between reactants and the PRC. The rate constants were calculated in a multi-TS/multi-conformer way at the SVECV-f12/m06Tz and SVECV-f12/mn15Tz levels of theory. The SVECV-f12 method is consistent in its predictions in both systems and exhibits only minor deviations from the experimental rate constants. Despite some specific differences due to the DFT method supporting the SVECV-f12 calculations, both methodologies predict a significant H-abstraction contribution in the AMS + OH gas phase reaction, which explains the high formation yield for acrolein determined experimentally.

Lipidomics analysis unveils the dynamic alterations of lipid degradation in rice bran during storage

Recent explorations into rice bran oil (RBO) have highlighted its potential, owing to an advantageous fatty acid profile in the context of health and nutrition. Despite this, the susceptibility of rice bran lipids to oxidative degradation during storage remains a critical concern. This study focuses on the evolution of lipid degradation in RBO during storage, examining the increase in free fatty acids (FFAs), the formation of oxylipids, and the generation of volatile secondary oxidation products. Our findings reveal a substantial rise in FFA levels, from 109.55 to 354.06 mg/g, after 14 days of storage, highlighting significant lipid deterioration. Notably, key oxylipids, including 9,10-EpOME, 12,13(9,10)-DiHOME, and 13-oxoODE, were identified, with a demonstrated positive correlation between total oxylipids and free polyunsaturated fatty acids (PUFAs), specifically linoleic acid (LA) and α-linolenic acid (ALA). Furthermore, the study provides a detailed analysis of primary volatile secondary oxidation products. The insights gained from this study not only sheds light on the underlying mechanisms of lipid rancidity in rice bran but also offers significant implications for extending the shelf life and preserving the nutritional quality of RBO, aligning with the increasing global interest in this high-quality oil.

Volatile fatty acids production from kitchen waste slurry using anaerobic membrane bioreactor via alkaline fermentation with high salinity: Evaluation on process performance and microbial succession

In this study, a pilot-scale anaerobic membrane bioreactor (AnMBR) was developed to continuously produce volatile fatty acids (VFAs) from kitchen waste slurry under an alkaline condition. The alkaline fermentation effectively suppressed methanogenesis, thus achieving high VFAs production of 60.3 g/L. Acetic acid, propionic acid, and butyric acid accounted for over 95.0 % of the total VFAs. The VFAs yield, productivity, and chemical oxygen demand (COD) recovery efficiency reached 0.5 g/g-CODinfluent, 6.0 kg/m3/d, and 62.8 %, respectively. Moreover, the CODVFAs/CODeffluent ratio exceeded 96.0 %, and the CODVFAs/NH3-N ratio through ammonia distillation reached up to 192.5. The microbial community was reshaped during the alkaline fermentation with increasing salinity. The membrane fouling of the AnMBR was alleviated by chemical cleaning and sludge discharge, and membrane modules displayed a sustained filtration performance. In conclusion, this study demonstrated that high-quality VFAs could be efficiently produced from kitchen waste slurry using an AnMBR process via alkaline fermentation.

OXIDATIVE REGENERATION OF METAL COMPLEX CATALYTIC SYSTEM

When carrying out thermocatalytic destruction of hydrocarbon feedstock, catalysts are deactivated due to the formation of surface coke, which blocks active centers. In order to restore their previous activity and selectivity, as well as extend their service life, a process of catalyst regeneration is carried out. One of the effective methods for restoring the original activity of deactivated catalysts is oxidative regeneration, which is based on the oxidation of coke deposits on the surface of the catalyst. The article examines the dependences of the formation of surface coke when varying the temperature regime of the process from 450 °C to 550 °C during the thermocatalytic destruction of heavy petroleum feedstock – West Siberian oil fuel oil in the presence of a new metal complex catalytic system, where the active component is a chloroferrate complex (NaFeCl4 or TCFN) in an amount 10 %, deposited on a carrier, which is a deeply decationized Ymmm zeolite of the acidic form (H-form). The patterns of oxidative regeneration of a metal-complex catalytic system were studied by distilling off highly volatile products in a flow of inert gas (helium) and oxygen-containing gas. During the experiments, it was found that with an increase in the temperature of the thermocatalytic destruction process from 450 °C to 550 °C, a slight increase in coarse deposits on the surface of the catalyst was observed from 2,6 % wt. up to 3,5 % wt. respectively. When carrying out the process of oxidative regeneration of a carbonized catalyst with air oxygen (in a flow of helium) at a temperature of 500 °C for 60 min only volatile components are initially removed, and further calcination takes up to 180 min allows for complete burning of surface coke.

Genomic Characterization of Wild Lactobacillus delbrueckii Strains Reveals Low Diversity but Strong Typicity.

Investigating the diversity of a given species could give clues for the development of autochthonous starter cultures. However, few studies have focused on the intraspecies diversity of Lactobacillus delbrueckii strains, a technologically important lactic acid bacterium for the dairy industry. For this reason, Lactobacillus delbrueckii strains from the Saint-Nectaire Protected Designation of Origin (PDO) area were isolated and characterized. Genetic diversity was determined based on core genome phylogenetic reconstruction and pangenome analysis, while phenotypic assessments encompassed proteolysis and volatile compound production potential. A total of 15 L. delbrueckii ssp. lactis unique new strains were obtained. The genetic analysis and further proteolytic activities measurement revealed low variability among these Saint-Nectaire strains, while substantial genetic variability was observed within the L. delbrueckii ssp. lactis subspecies as a whole. The volatile compound profiles slightly differed among strains, and some strains produced volatile compounds that could be of particular interest for cheese flavor development. While the genetic diversity among Saint-Nectaire strains was relatively modest compared to overall subspecies diversity, their distinct characteristics and pronounced differentiation from publicly available genomes position them as promising candidates for developing autochthonous starter cultures for cheese production.