Phenolic Products Research Articles

Sources, Sinks, and Oxidation Pathways of Phenolic Compounds in South Korea Constrained Using KORUS‐AQ Airborne Observations

Abstract Aromatics are an important class of volatile organic compounds with impacts on human health. The impacts of aromatics and their oxidation products vary. While the chemistry and major pathways of the precursor aromatics are relatively well understood, the same is not true for their phenolic oxidation products. Here, we use new observations of aromatic oxidation products collected during the Korea‐United States Air Quality aircraft campaign to evaluate the aromatic chemical mechanism in the GEOS‐Chem v13.4.0 chemical transport model. Based on these results, we implement changes to emissions, add ethylbenzene chemistry, and introduce phenol production from ethylbenzene and toluene oxidation. These changes improve simulation of benzene (reducing normalized mean bias from 24% to −9%) and phenol (−71% to −42%). Model biases increase for toluene, xylene, and cresol, but simulated mixing ratios remain within measurement uncertainties and observed interquartile ranges. We identify potential toluene emission overestimates from petrochemical complexes in Ulsan and Daesan and underestimates from the Daegu dyeing industrial complex, and underestimates of benzene emissions from China. Using the updated model, we find benzene and toluene contribute equally to phenol production in the boundary layer (accounting for 40% of phenol production each), and that toluene and ethylbenzene are atmospherically relevant precursors of phenol. Phenol and cresol loss is found to be dominated by OH oxidation (73% for both phenol and cresol). We find that benzaldehyde is the dominant source of nitrophenol production (67%), although phenol dominates nitrophenol production at night.

Formation of phenolic compounds from roasted sesame hull lignin: Impact of lignin structure.

Formation of phenolic compounds from roasted sesame hull lignin: Impact of lignin structure.

A Microbial Food Web Dynamics Under the Influence of Leachate Recirculation

The three-tiered microbial food chain without maintenance under leachate recirculation is the subject of a mathematical seven-dimensional dynamical system that is proposed in this work. This model captures the complex interactions between chlorophenol degraders, phenol degraders, and methanogens in the presence of hydrogen inhibition. The implementation allows for investigation of how hydrogen levels affect the overall system dynamics and phenol production. There is a thorough qualitative analysis provided. A stability analysis of equilibrium points is performed. It is demonstrated that the persistence of the three bacteria is correlated with the existence of the positive equilibrium point, assuming some monotonicity properties on the growth rates. Asymptotic coexistence is satisfied, although periodic orbit possibilities are not ruled out. In order to decrease the amount of organic materials within the reactor, we suggest an optimal strategy on the rate of leachate recirculation in the second stage. Lastly, we offer a few numerical investigations that support and strengthen the theoretical conclusions.

Antagonistic potential and analytical profiling of plant probiotic bacteria using chromatography and mass spectrometry techniques against Botrytis cinerea and Fusarium oxysporum

Plant probiotics are bacteria that play a significant role in enhancing plant growth and health. To understand the interactions between plant probiotics and host plants, a comprehensive approach of antagonistic activity and analytical methods such as high-performance liquid chromatography (HPLC), gas chromatography‒mass spectrometry (GC‒MS), and Fourier transform infrared (FT‒IR) spectroscopy, were employed. The previously isolated bacterial strains, namely, Corynebacterium accolens strain CNTC Th1/57, Bacillus rugosus strain SPB7, Lactobacillus pasteurii DSM 23907 and Cytobacillus firmus strain NBRC 15306, were exposed to antagonistic testing against Botrytis cinerea and Fusarium oxysporum. Considering the results of the antagonistic activity both in vitro and statistically, the bacterial strains Bacillus rugosus strain SPB7 and Lactobacillus pasteurii DSM 23907 presented greater zones of inhibition. Hence these bacteria were moved to obtain comprehensive insights into the chemical composition. HPLC and GC‒MS resulted in the identification of phenols and organic acids. These results were further confirmed by FT-IR, which revealed a peak at 3500 cm−1 for Bacillus rugosus strain SPB7, where O–H, aromatic C-H and aromatic C = C stretching vibrations were also observed at 3069 and 1549 cm−1. The peak at 1736 cm−1 corresponds to the carboxyl group (-COOH) as the functional group with respect to Lactobacillus pasteurii DSM 23907. Further confirmation was performed by observing the other absorption bands at 3451 cm−1 and 2958 cm−1, indicating the presence of hydroxyl group (O–H) and alkyl group (C-H) stretching vibrations, thus confirming their potential for the production of phenols and organic acids, respectively, by bacteria. This findings would make a way to explore plant diseases, tolerance against pathogens, and also study ecological role of these bacteria in plant communities.Graphical

Bio-Based Phenol from Cashew Nutshells by Catalytic Hydrocardanol Trans-Alkylation Using H-ZSM-5 Zeolite.

Cardanol, an unsaturated long-chain alkylphenol derived from agricultural waste, has potential as a sustainable substrate for bio-based phenol production. Herein, we demonstrate the potential of hydrocardanol, readily obtained through cardanol hydrogenation, as a viable feedstock for phenol production via trans-alkylation using toluene as the alkyl acceptor. HZSM-5 (SiO2/Al2O3 molar ratio = 80) exhibited a 53.7% phenol yield with a high phenolics balance (86.7%) from a 10 wt% hydrocardanol solution at full conversion in a batch reactor. In contrast, cardanol gave only 27.1% phenol under the same reaction conditions. This improved yield with hydrocardanol is attributed to suppressed formation of bi- and/or polycyclic phenols via self-alkylation, due to the higher thermal stability of the saturated side chain. Re-alkylation of the desired phenol product largely limited the phenol yield. The model reaction experiments with phenol and 1-pentadecene showed that the reaction proceeds via hydrocardanol dealkylation on the zeolite, followed by rapid isomerization, cracking and oligomerization reactions of the resulting long-chain olefin, and re-alkylation of toluene and phenol. This indicated that phenol alkylation could be suppressed by reducing the hydrocardanol-to-toluene ratio. This approach was validated in a fixed-bed flow reactor, achieving a high phenol yield (>95%) with a high carbon balance (>99%).

Chlorine Radical Mediated Deprotection of Aryl Ethers via Photocatalyzed Ligand‐to‐Metal Charge Transfer

Abstract A photochemical FeCl3‐catalyzed the C(sp3)‐H activation of aryl ethers was achieved via hydrogen atom abstraction strategy of chlorine radicals. Followed by the tandem hydrolysis, the aryl ethers were converted into the corresponding phenol products (28 examples). Compared with traditional reductive deprotection methods for aryl ethers, such as Pd/C, Mg/alcohol system and so forth, our strategy features mild reaction conditions, atom economy, and wide functional group compatibility. In addition, several control experiments were conducted to investigate the reasonable mechanism.

Nickel-Driven Electrochemical Upgrading of Kraft Lignin to Value-Added Aliphatic and Phenolic Products

The depolymerization of lignin represents a promising strategy for its efficient utilization as a precursor for industrial raw materials. However, achieving both high efficiency and environmental sustainability remains a significant challenge. In this study, we present an aqueous electrochemical approach employing nickel as an electrocatalyst, enabling both depolymerization and partial de-aromatization of Kraft lignin under mild reaction conditions. Using an aqueous sodium carbonate medium, room temperature and ambient pressure, we achieved lignin depolymerization over reaction times ranging from 5 to 20 h. Characterization by nuclear magnetic resonance (NMR) spectroscopy confirmed the formation of aliphatic products such as acetate and formate, while high-resolution mass spectrometry (HRMS) confirmed the formation of a wide range of phenolic compounds. The conversion of lignin into valuable aromatic and aliphatic compounds offers a promising pathway for the synthesis of a wide range of organic chemicals and their subsequent industrial utilization, thereby supporting the development of a more sustainable economy.

Oxyfunctionalisation of anisole and its selected reaction products by unspecific peroxygenases

Oxyfunctionalisation of anisole and its selected reaction products by unspecific peroxygenases

Detection and O-methylation of bromocatechols, brominated/hydroxylated analogs of diphenyl ethers and dibenzo-p-dioxins in thorny oyster (Spondylus squamosus) and pen shell (Atrina vexillum) from the Philippines.

Detection and O-methylation of bromocatechols, brominated/hydroxylated analogs of diphenyl ethers and dibenzo-p-dioxins in thorny oyster (Spondylus squamosus) and pen shell (Atrina vexillum) from the Philippines.

In-situ hydrogen-mediated catalytic transfer hydrogenolysis of Kraft lignin for highly selective production of monomeric phenols

In-situ hydrogen-mediated catalytic transfer hydrogenolysis of Kraft lignin for highly selective production of monomeric phenols

Cellulose-derived biocatalysts and neutralizing gels for pesticides: How to eliminate and avoid intoxication?

Cellulose-derived biocatalysts and neutralizing gels for pesticides: How to eliminate and avoid intoxication?

Combined Benzothiadiazole and Heat Shock Treatment Accelerates Wound Healing in Sweet Potatoes.

Mechanical damage resulting from the harvesting process and subsequent handling can contribute to the deterioration and decay of sweet potatoes (Ipomoea batatas) throughout storage. These detrimental effects can be mitigated by wound healing process. This study investigated the effects of combined benzothiadiazole (BTH) and heat shock (HS) treatment on the wound healing activity of sweet potatoes, along with the underlying mechanisms. Sweet potatoes subjected to BTH+HS treatment showed increased lignin formation and more hardness in the healing tissues than those individually treated with BTH or HS. The BTH+HS treatment surpassed each other in preventing weight loss, augmenting total phenolic and flavonoid compound production, and promoting reactive oxygen species (ROS) formation. In line with these results, the activity levels of enzymes associated with the phenylpropanoid pathway (phenylalanine ammonia-lyase, cinnamic acid 4-hydroxylase, 4-coumarate-CoA ligase, and cinnamyl alcohol dehydrogenase) and ROS metabolism (NADPH-dependent oxidases, superoxide dismutase, catalase, and peroxidase) were also enhanced to a greater degree in response to BTH+HS treatment relative to BTH or HS alone. Combining BTH and HS treatment is a more efficacious approach to improve sweet potato wound healing, with these benefits closely linked to the activation of the phenylpropanoid pathway and ROS metabolism.

Insect meals in cat diets and their effects on digestibility, physiology, and gut microbiota

Insects are a valuable source of nutrients, but little is known about their nutritional value for companion animals. In this study, we evaluated the inclusion of three insect meals in cat diets (Cinerea cockroach, CC; Madagascar cockroach, MC; and Superworm, SW) at two different levels (7.5 and 15%) on apparent digestibility coefficient (ADC), blood parameters, fecal pH, short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), phenol and indole production, and gut microbiota during six experimental periods of 15 days each. No differences were found for ADC, except for chitin in which MC registered the highest ADC. The fermentative product analysis showed that propionate displayed higher abundance in all insect treatments compared to the control group. Moreover, cats fed CC diet resulted in higher fecal butyrate while higher 4-methylphenol was registered in cats fed MC and SW diets. No significant differences were found for fecal pH and score, as well as no change in urea, creatinine, and blood count were registered. No differences were registered for total fecal SCFA, BCFA, phenol, and indole production compared to the control group or between insect meal fed groups. The fecal microbiota analyzed by gene 16S rRNA sequencing of cats did not register differences in alpha or beta diversity. In conclusion, dietary inclusion of insect meal up to 15% is a suitable alternative food for adult cats.

Predicting the environmental consequences of different energy and material applications for Bavarian hardwood harvest

Abstract Nowadays, hardwood in Germany is mainly used for heat production despite several available or developed material applications. However, questions arise about how hardwood can be used in the future to best meet its environmental reduction potential, including consequences through replacing non‐renewable energy carriers or products.A prospective, consequential life cycle assessment was conducted for the additional hardwood harvest in a regional case study in Germany. The study included conventional wood products (such as glued‐laminated beams, viscose fibers, and particle boards) and emerging products like lignin‐based carbon fibers and phenol, as well as their respective substitutes.Results showed that shifting hardwood to material applications reduced environmental impacts when the heat was generated via heat pumps. The production of viscose and carbon fibers can lead to great reductions if the chosen substitutes are effectively replaced. The glulam beam production reduces most environmental impacts to a smaller extent, but depends less on the product replaced. Lignin‐based phenol and particle board production lead to few environmental consequences.Future hardwood use for material applications can reduce environmental impacts if heat pumps are used for heat generation and the substitution is effective. Some applications may not achieve significant reductions due to quality issues or limited production output. Hardwood might also be required to compensate for the decline in softwood supply, achieving negligible environmental consequences.Future research should focus on flexible processing for mixed hardwood species and its effective substitution of non‐wood products.

Nanoparticle-mediated enhancement of alkaloid, phenolic, and flavonoid production in Datura callus cultures

Nanoparticle-mediated enhancement of alkaloid, phenolic, and flavonoid production in Datura callus cultures

Effects of Methyl Jasmonate on Phenolic Acid Production in in vitro Root Cultures of Gentiana lutea and Gentiana boissieri

This research examines the impact of varying durations and concentrations of methyl jasmonate (MeJA) treatments on the phenolic acid production in in vitro roots of Gentiana lutea and Gentiana boissieri. These species are highly valued for their bioactive metabolites in the pharmaceutical and food industries, as well as their ornamental appeal in horticulture. Nevertheless, both species face threats from overharvesting and human-induced pressures. The study utilized root cultures grown in liquid media, followed by MeJA elicitation at concentrations of 0.1, 0.5, and 1.0 mM for durations of 2, 4, 6, 8, and 10 days. Phenolic acids, including gallic acid (GA), chlorogenic acid (CGA), caffeic acid (CA), p-coumaric acid (p-QA), o-coumaric acid (o-QA), ferulic acid (FA), cinnamic acid (CNA), and rosmarinic acid (RA), were quantified in the harvested roots using HPLC. The results revealed that phenolic acid levels were influenced by both MeJA concentration and application duration. The findings highlight that MeJA, when optimally applied, can enhance phenolic acid production in in vitro root cultures of G. lutea and G. boissieri effectively.

Cumene-to-Phenol Process Mediated by Bromine Radicals through Photoinduced Ligand-to-Metal Charge Transfer

Abstract Selective C–H activation via hydrogen atom transfer (HAT) has gained significant interest recently. One industrial application for HAT can be found in the tertiary benzylic C–H bond of cumene for producing phenol, a versatile chemical feedstock for various industries. However, the overall phenol yield remains low using the existing Hock process due to the poor selectivity towards the key reaction intermediate, cumene hydroperoxide (CHP). Here, we demonstrate an efficient strategy for phenol production through photooxidation of cumene to CHP using iron bromide under blue light irradiation, where bromine radicals (generated in situ via ligand-to-metal charge transfer) are used as hydrogen atom abstractors. Mechanistic studies revealed the cumene-to-CHP conversion occurred via a tertiary C–H bond abstraction by a radical mechanism, and the acetic acid and water additives increased CHP selectivity through stabilizing peroxides. The cumene-phenol process achieved up to 88% yield of CHP in 1 hour and could be used with a wide range of substrates. We thus developed a selective, mild, and efficient phenol production method using iron bromide under photooxidative conditions.

Phenolic supplements: testing an approach to limit Sphagnum decomposition in a Sphagnum farming system

Phenolic compounds have been proposed to influence decomposition by inhibiting extracellular enzyme activities, as described in the enzymic latch mechanism (ELM). This study examined the effects of phenolic treatments on Sphagnum decomposition, productivity, and biomass accumulation within a Sphagnum farming system. A split-plot experiment with three phenolic treatments was implemented in two cultivation basins established with mosses dominated by the Acutifolia or Sphagnum subgenus. Phenolic treatments were wood pellets (wood), old roots from peat harrowing (root), and no addition (control). Phenolic additions did not result in a measurable reduction in decomposition rates nor was Sphagnum productivity or biomass affected by the experimental treatments. Both subgenera functioned as approximately similar small carbon dioxide (CO2) sinks, with values such as −2 ± 1 g CO2 m−2 d−1 (Acutifolia) and −0.2 ± 0.8 g CO2 m−2 d−1 (Sphagnum). Phenolic additions in both subgenera resulted in higher CO2 values as net ecosystem exchange compared to the control, which could be linked to emissions resulting from wood and root decomposition. In both subgenera, phenolic additions neither increased peat phenolic concentrations nor inhibited enzyme activities compared to the control. The current study did not validate the potential of phenolics in limiting decomposition as theorized in the ELM. The short duration of the experiment may have restricted the effect of phenolic products applied at the surface from reaching the ∼10 cm depth where peat was sampled. This could explain the absence of an inhibitory effect of phenolic products on enzyme activities. Therefore, it is recommended to conduct various sample analyses at different depths to better understand phenolic–enzyme interactions in a Sphagnum farming system.

Cyclodextrins increase phytosterol and phenolic compound production in Thymbra capitata cell cultures

Cyclodextrins increase phytosterol and phenolic compound production in Thymbra capitata cell cultures

Timing Is Everything: The Metabolic Partitioning of Suberin-Destined Carbon.

Suberin is a cell wall-associated biopolymer that possesses both poly(phenolic) and poly(aliphatic) elements assembled into chemically and spatially distinct domains. Domain-specific monomers are formed via a branched pathway between phenolic and aliphatic metabolisms. Previous transcript accumulation data (RNAseq) from early stages of wound-induced suberization revealed highly coordinated, temporal changes in the regulation of these two branches. Notably, phenolic metabolism-associated transcripts accumulated first, indicating a preference toward phenolic production early on post-wounding. To better understand the dynamics of suberin monomer biosynthesis and assembly, we assessed carbon allocation between phenolic and aliphatic metabolisms during wound-induced suberization. To do so, [13C6]-glucose was administered to wound-healing potato tuber discs at different times post-wounding, and patterns of heavy carbon incorporation into (1) primary metabolites and (2) the suberin polymer were assessed. During early stages of wound-healing, carbon from glucose was rapidly incorporated into phenolic-destined metabolites, while at later stages it was shared between phenolic- and aliphatic-destined metabolites. Similarly, the pattern of labelled carbon incorporation into the poly(aliphatic) domain reflected a greater dedication of carbon towards 18:1 w-hydroxy fatty acid and 18:1 dioic acid (the two most abundant aliphatic monomers in potato suberin) later in the wound healing time course.