Aromatic Ring Compounds Research Articles

Enhanced co-pyrolysis synergies between cedar and Naomaohu coal volatiles for tar production

Tar production from co-pyrolysis is highly dependent on synergies between coal and biomass volatiles. Therefore, enhancing their interactions during co-pyrolysis is crucial. In this study, three mixing modes, including mechanical mixing (M-type) and two layered loading modes (the U-type with upper Naomaohu coal (NMH) and lower cedar sawdust (CS) and the L-type with upper CS and lower NMH), were specially designed to explore the synergies between NMH and CS volatiles based on the analyses of products distribution, tar fractions and compositions, and stable radicals in char. The results show that sufficient void space is required for the co-pyrolysis synergies between CS and NMH volatiles. With the M-type mode, the CS volatiles preferably formed char on the NMH surface in a limited void space, inhibiting coal pyrolysis. The layered L-type and U-type modes enhanced the co-pyrolysis synergies, and the CS volatiles acted as hydrogen donors to enhance tar production. Compared with the L-type mode, the U-type mode resulted in better synergies between NMH and CS volatiles, contributing to higher tar yield of 44.68 wt%. In addition, the volatile synergies were conductive to the formation of aliphatic chain radicals in char, methyl-containing compounds, and 3–4 ring aromatic compounds in tar. This research will guide the optimization of tar production and co-pyrolysis technique exploitation.

Photoluminescence with an unusual open-loop and rigid delocalized conjugated structure in quantum dots

It is well known that almost all photoluminescent molecules are aromatic or heterocyclic ring compounds for bioimaging analysis. A question remains as to whether a breakthrough can be achieved regarding a novel photoluminescent molecule without a ring structure, and in a what manner. In this study, we explored the photoelectric conversion and structure of photoluminescent compounds, and constructed an intra-molecular coupling positive–negative-junction (PNJ) with an open-loop and rigid Π56 delocalized conjugated structure of the coupling p-π conjugate system. This was performed to enable strong absorption of the R/tail-end band for the high probability of an n → π*/n → σ* electron transition for photoluminescence production. Subsequently, the Π56 structure was formed in a short-chain aliphatic molecule as a hydrolytic product of citric acid and urea, and computational methodology was employed to estimate the feasibility of the molecule photoluminescence. Finally, a quantum dot material was fabricated from the aliphatic molecule, the optical properties of the quantum dots were investigated, and the biocompatibility and bioimaging ability of quantum dots were assessed. This work presents not only a theoretical exploration but also practical application of a new strategy to obtain molecules, compounds, and materials with bioimaging.

Recent Achievement in the Synthesis of Thiophenes

Thiophene derivatives are aromatic five-membered ring compounds made up of one sulfur as heteroatom. These compounds are present in a large number of natural and unnatural compounds with valuable bioactivities. Many of them have a wide range of applications in medicinal chemistry such as antimicrobial, anticancer, antiparasitic, anti-inflammatory, and antihypertensive activities. Some of them are famous drugs in the market nowadays such as Cefoxitin, Cephalothin, Cephaloridine, Temocillin, tinoridine, tiaprofenic acid, tenoxicam, suproprofen and Raltitrexed. The use of thiophene derivatives has also been found in other fields. The application of thiophenes in organic materials thanks to their electronic properties has been reported. In organic synthesis, thiophenes have also drawn the attention of chemists because of their values as intermediates. The employment of thiophene derivatives in agrochemicals, flavors, and dyes has also been found. Due to diverse applications, the synthesis of thiophene derivatives has attracted a lot of attention. Numerous known synthetic methods such as Gewald and Fiesselmann methods have been modified and improved. Furthermore, a large number of novel synthetic approaches to the synthesis of thiophenes have been developed. This review will focus on considerable studies on the synthesis of thiophenes which date back from 2012. In this review, we discussed recent achievement in the synthesis of thiophene derivatives. Some established methods have been modified and improved, while other novel methods have been discovered. Diverse catalysts were employed for these transformations. In some syntheses, reaction mechanisms were also displayed. Many methods for the synthesis of thiophenes have been developed recently. In the near future, more imaginative approaches for the synthesis of thiophenes will be investigated to improve the efficiency and versatility or the use of environmentally friendly and economical procedures for thiophene synthesis will be proposed. Application to natural product synthesis and drug synthesis is probably the next challenge in the field.

Potential for and Distribution of Enzymatic Biodegradation of Polystyrene by Environmental Microorganisms.

Polystyrene (PS) is one of the main polymer types of plastic wastes and is known to be resistant to biodegradation, resulting in PS waste persistence in the environment. Although previous studies have reported that some microorganisms can degrade PS, enzymes and mechanisms of microorganism PS biodegradation are still unknown. In this study, we summarized microbial species that have been identified to degrade PS. By screening the available genome information of microorganisms that have been reported to degrade PS for enzymes with functional potential to depolymerize PS, we predicted target PS-degrading enzymes. We found that cytochrome P4500s, alkane hydroxylases and monooxygenases ranked as the top potential enzyme classes that can degrade PS since they can break C–C bonds. Ring-hydroxylating dioxygenases may be able to break the side-chain of PS and oxidize the aromatic ring compounds generated from the decomposition of PS. These target enzymes were distributed in Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes, suggesting a broad potential for PS biodegradation in various earth environments and microbiomes. Our results provide insight into the enzymatic degradation of PS and suggestions for realizing the biodegradation of this recalcitrant plastic.

Natural Quinone Molecules as Effective Cath Ode Materials for Lithium-Ion Batteries: A First-Principles Study

The use of biomass resources for energy storage provides a promising solution to alleviate energy crisis and environmental pollution. By employing first principles calculations, we explored the potential of using natural carbonyl-containing fused ring aromatic compounds, namely natural quinone molecules, as electrode materials for lithium-ion batteries (LIBs). Different side functional groups can significantly influence the lithium storage mechanisms, including the lithiation reaction sites and reaction sequence. Oxygen-containing functional groups at the ortho position facilitate the lithiation process by forming Li-O bond, while electron-withdrawing groups can enhance the redox activity of quinones. Natural quinone derivatives of 1-hydroxyanthraquinone (1-HAQ), 1,4-dihydroxyanthraquinone (1,4-DHA), methyl 3-hydroxy-1,4-naphthoquinone-2-carboxylate (MHNQC), methyl 1,2-dihydro-4-hydroxy-1,2-dioxonaphthalene-3-carboxylate (MDHDNC), 2-carbamoyl-3-hydroxy-1,4-naphthoquinone (CHNQ) and 2-methoxy-1,4-naphthoquinone (MNQ) exhibit high capacity of 239, 223, 231, 231, 247 and 285 mAh g-1 and high redox potential of 2.33, 2.49, 2.76, 2.77, 2.44 and 2.45 V, respectively, thus are predicted to be potential cathode materials for LIBs.

Pyrolysis of scrap tire by utilizing zeolite as catalyst

Pyrolysis of waste tyres has been taken along 2 stage bed reactor. Waste tyres has been 1rst pyrolysis under perfect bed reactor, letter included pyrolysis gases has been forwarded by secondary catalytic reactor involved along 2 kinds of zeolite catalysts, which has been ultras table HY type & ZSM-5 catalyst. The Temperature of catalytic has been calculated regards observing issues on yield of products through waste tyres pyrolysis catalyst. Under this paper outputs shows that along enhance temperature of catalytic yield of gas enhanced at increase of yield of oil. It was describing that there was dramatic enhancement under concentration regards single ring aromatic compounds under fraction regards catalysis of derived oils. A un-catalyst tire pyrolysis was carried out under this paper, under order to correlate the pyrolysis of idle tires along the HY Impetus & ZSM-5 Impetus. The pyrolysis temperature was changed through 450 to 600 OC the impulses were replaced along similarly sized Such like ignorance reached counts under fraction of light around 11.63 wt%, o-xylen 4.40 wt%, benzene 1.7 wt% & m/p-xylen 12.3 wt% along HY catalyst, at temperature of pyrolysis, temperature of catalysis & ration of catalyst tyre around 400, 500 & 0.5, Under which light fraction is around 70.8 wt% under derived oil. Waste tires Synergist pyrolysis uses catalyst of zeolite HY & ZSM-5 which was observed related to effect regards temperature of reactant under yield items. Results show that effect of ZSM5 & catalyst zeolite HY has been to prove diminish yield regards oil along confirming enhancement under yield of gas.

Anion‐Templated Self‐Assembly of Silver(I) Frameworks Bridged by μ‐, μ3‐, μ4‐1,2,4,5‐Tetrazine

The formation of Ag(I)‐1,2,4,5‐tetrazines(ttz) based coordination polymers via the Ag−N coordination and anion−π interactions is described. Coordination‐driven self‐assembly is a key step to construct coordination polymers, and ttz, an electron‐deficient aromatic ring compound, forms interesting anion−π interactions. In this study, a series of silver salts, AgX [X = BF4, PF6 and CF3SO3 (OTf)], is introduced to determine the influence of shape and size of anions on the formation of coordination polymers, {[Ag(ttz)](BF4)}n (1), {[Ag2(ttz)3](PF6)2}n (2) and {[Ag2(ttz)3(OTf)](OTf)}n (3). It shows different types of channels in polymers and the coordination modes of ttz (μ, μ3, and μ4). The structure of coordination polymers and the influence of anion−π interactions are revealed by single crystal X‐ray diffraction. In particular, 3 shows not only the anion−π interaction but also the coordination between the anion and Ag(I) which contributes to the unique framework compared to 1 and 2.

Re-engineering of peptides with high binding affinity to develop an advanced electrochemical sensor for colon cancer diagnosis

Colorectal cancer (CRC) develops from polyps in the inner large intestine or rectum and an increasing incidence and high mortality rate has been observed in humans. Currently, colonoscopy is the preferred modality for early CRC diagnosis. However, this technique has several limitations, such as high medical costs and intricate procedures, leading to increasing demands for the development of a new, simple, and affordable diagnostic method. In this study, an advanced electrochemical biosensor based on rationally designed affinity peptides was developed for discriminating adenoma to carcinoma progression. Amino acid-substituted and rationally designed synthetic peptides (BP3-1 to BP3-8) based on in silico modeling studies were chemically synthesized, and covalently immobilized onto a gold electrode using aromatic ring compounds through surface chemistry techniques. The binding performance of the developed sensor system was observed using square wave voltammetry (SWV). The peptide BP3-2 was selected depending on its relative binding affinity; SWV indicated the limit of detection of BP3-2 for LRG1 to be 0.025 μg/mL. This sensor could distinguish the adenoma-carcinoma transition with improved binding abilities (specificity and selectivity), and stability in plasma samples spiked with LRG1 and real samples from patients with CRC. These results indicate that this electrochemical sensor system can be used for early monitoring of the colorectal adenoma to carcinoma progression.

Abstract LB-236: Design, synthesis, and assessment of anticancer properties of pyrazolopyrimidine derivatives as Glycogen Synthase Kinase-3β inhibitors

Abstract Glycogen synthase kinase-3β (GSK-3β) is a serine/threonine kinase with a crucial role in several key cellular functions including tumor cell proliferation and survival. Yet, GSK-3β has emerged as an attractive target for the development of anti-cancer agents. Several small-molecule have been developed as GSK-3β inhibitors. Amongst, several pyrazolopyrimidines based ATP-competitive inhibitors were identified as promising GSK-3β inhibitors. In this work, several pyrazolo[3,4-d]pyrimidine derivatives were designed, synthesized and assessed for their potential anticancer activity. The new compounds are categorized under two templates, Template A and Template B. In these templates two different linkers with varying lengths and electronic properties were used to link additional aromatic ring systems to the core pyrazolopyrimidine scaffold. The aromatic ring systems were designed with different electronic and bonding properties to test their GSK-3β inhibitory activity and consequently their anticancer properties. All compounds under investigation showed GSK-3β inhibitory properties with IC50's ranging from 0.17- 1.01 µM compared to Tideglusib (standard GSK-3β inhibitor) which showed IC50 of 0.22 µM. Furthermore, the compounds were tested for their potential cytotoxicity against two breast cancer cells (MCF-7 and MDA-MB-231) and lung cancer cells (A549). Only one compound from Template B which possesses the longer hydrazide linker and 2,3-dihydroxy phenyl aromatic ring (compound 27), showed considerable cytotoxic effects against MCF-7, MDA-MB-231 and A549 cells (IC50's of 2.4, 2.4 and 2.3 µM, respectively). Compounds 21, 24, 25 and 26 showed weaker cytotoxic effects against cell lines under investigation (IC50's ranged from 29 to 93 µM). DNA content flow-cytometry analysis was undertaken to evaluate the potential effects of compound 27 on the cell cycle distribution of cell lines under investigation. Compound 27 induced significant antiproliferative effect and accumulation of cells in G0/G1-phase after 24 h of exposure. Longer exposure (48 h) to compound 27 resulted in cell cycle arrest in G2/M-phase. Additional assessment for programmed/non-programed cell death using annexin-V/FITC and acridine orange staining coupled with flow-cytometric analysis showed the ability of compound 27 to induce apoptosis as well as autophagy in all cells under investigation. In conclusion, compound 27 represents a promising GSK-3β inhibitor with potential anticancer properties via the induction of cell cycle arrest with subsequent cellular stress and induction of apoptosis and autophagy. Citation Format: Ahmed T. Negmeldin, Mohammed K. AbdElhameid, Dalia Y. Alsaeedy, Fatiha Hammed, Rasha M. Allam, Walid El-Sayed, Ahmed M. Al-Abd. Design, synthesis, and assessment of anticancer properties of pyrazolopyrimidine derivatives as Glycogen Synthase Kinase-3β inhibitors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-236.

Comparison of pyrolysis of live wildland fuels heated by radiation vs. convection

During wildland fires, which include both planned (prescribed fire) and unplanned (wildfire) fires, live and dead plants may be subject to both radiative and convective heat transfer mechanisms. In this study, the pyrolysis of 14 live plant species native to the forests of the southern United States was investigated using a flat-flame burner (FFB) apparatus under three heating modes in order to mimic pyrolysis of plants during wildland fires. The heating modes were: (1) radiation-only, where the plants were pyrolyzed under a moderate heating rate of 4 °C s−1 (radiative flux of 50 kW m−2); (2) convection-only, where the FFB apparatus was operated at a high heating rate of 180 °C s−1 (convective heat flux of 100 kW m−2); and (3) a combination of convection and radiation, where the plants were exposed to both convective and radiative heat transfer mechanisms. Data were also compared with slow heating experiments (0.5 °C s−1). During the experiments, the pyrolysis products were collected and analyzed using GC–MS for the analysis of tars and GC-TCD for the analysis of light gases. The results indicate that the highest light gas and tar yields were obtained from the combined mode, which was performed at a higher pyrolysis temperature and heating rate. CO, CO2, CH4, and H2 were the major light gas species in all three heating modes. The radiation-only mode led to formation of primary tars and a few secondary tars consisting of aliphatic and 1–2 ring aromatic compounds with 1 to 3 attachments, including alkyl, hydroxyl, and methoxy groups.

Effect of steam-iron reaction on product characteristics and debromination during pyrolysis of epoxy-printed circuit boards.

In this work, the effect of steam and Fe powders on the pyrolysis of epoxy-printed circuit boards (e-PCBs) is in the focus of interest. It was found that higher yields of oil and gas were obtained at 600 °C in steam atmosphere than these obtained in N2 atmosphere. Due to the interactions of Fe powders and steam, the highest yield of H2 was obtained at 600 °C, accounting for 12.2 mmol g-1. In terms of the oil products, a high amount of phenol was produced in steam atmosphere, whereas an increased yield of single ring aromatic compounds was obtained, due to the dehydroxylation reactions promoted by steam-iron reaction. In steam atmosphere, the amount of organobromine compounds was greatly reduced. Fe powders removed most of organobromine compounds and HBr from oils. However, the bromine fixing ability of Fe powders was declined at 700 °C, leading to an increase in the content of inorganic bromine in liquid products. The characterization of spent Fe powders showed that the oxidation reactions of Fe powders with steam proceeded during the experiment, whereas the reduction reactions could be promoted at higher temperatures.

H<sub>3</sub>XF (X = Ge, Si)与芳香环化合物间硅键作用的理论研究

H<sub>3</sub>XF (X = Ge, Si)与芳香环化合物间硅键作用的理论研究

Influence of Fe based ZSM-5 catalysts on the vapor intermediates from the pyrolysis of brominated acrylonitrile-butadiene-styrene copolymer (Br-ABS)

The catalytic upgrading of the vapor intermediates from the pyrolysis of brominated acrylonitrile-butadiene-styrene (Br-ABS) was investigated over the Fe/ZSM-5 catalysts in a two-stage fixed bed reactor. Results showed that HZSM-5 and Fe/ZSM-5 catalysts exhibited high catalytic cracking activities, resulting in the increased yield of oil from 62.8 wt% to 64.3 wt% and 66.7 wt%, respectively. When the higher amounts of Fe/ZSM-5 catalysts were applied, the oil yield decreased to 59–61.6 wt%, whereas high amounts of coke were deposited on the catalysts. On the other hand, the higher percentages of the single ring and 2 ring aromatic compounds in the oils was obtained by the Fe/ZSM-5 catalysts, compared to the thermal pyrolysis and the catalytic upgrading by the parent HZSM-5 catalyst. The Fe/ZSM-5 catalysts significantly promoted the formation of styrene monomer and dimer derivatives. It could be proposed that the Fe based materials was in favor of the depolymerization of the polymer matrix, providing the styrene sources for the secondary oligomerization over the parent HZSM-5 catalyst. In addition, the Fe/ZSM-5 catalyst exhibited effective debromination performance, by means of cracking the organobromine compounds and capturing the inorganic bromine in the catalyst. The possible catalytic cracking mechanism over the Fe/ZSM-5 catalyst was discussed.

Gasoline Particulate Filters as an Effective Tool to Reduce Particulate and Polycyclic Aromatic Hydrocarbon Emissions from Gasoline Direct Injection (GDI) Vehicles: A Case Study with Two GDI Vehicles.

We assessed the gaseous, particulate, and genotoxic pollutants from two current technology gasoline direct injection vehicles when tested in their original configuration and with a catalyzed gasoline particulate filter (GPF). Testing was conducted over the LA92 and US06 Supplemental Federal Test Procedure (US06) driving cycles on typical California E10 fuel. The use of a GPF did not show any fuel economy and carbon dioxide (CO2) emission penalties, while the emissions of total hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx) were generally reduced. Our results showed dramatic reductions in particulate matter (PM) mass, black carbon, and total and solid particle number emissions with the use of GPFs for both vehicles over the LA92 and US06 cycles. Particle size distributions were primarily bimodal in nature, with accumulation mode particles dominating the distribution profile and their concentrations being higher during the cold-start period of the cycle. Polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs were quantified in both the vapor and particle phases of the PM, with the GPF-equipped vehicles practically eliminating most of these species in the exhaust. For the stock vehicles, 2-3 ring compounds and heavier 5-6 ring compounds were observed in the PM, whereas the vapor phase was dominated mostly by 2-3 ring aromatic compounds.

Phytochemical Screening and Total Phenolics and Flavonoids Contents of Hibiscus Rosa Sinensis. L Cultivated in Viet Nam

Phenolics and flavonoids are regarded as the highest potential of chemotherapeutic activities. This investigation was carried out to evaluate phytochemical and total phenolics content (TPC) and total flavonoids content (TFC) and Fourier-transform infrared spectroscopy (FTIR) spectral analysis of Hibiscus Rosa Sinensis L. extracts (crude extract, n-hexane extract, ethyl acetate extract, and methanol extract) for further applications in pharmaceutical development. Total phenolics were estimated by Folin-Ciocalteu method; while, Aluminum chloride was employed to quantify total flavonoids in the sample extracts. And, functional groups of Hibiscus Rosa Sinensis compound was determined using a FTIR-spectrophotometer. Results showed the leaves extracts to encompass the high amount of total phenolic and total flavonoid content. TPC values for crude extract, methanol extract, ethyl acetate extract and n-hexane extract were 57.09 ± 0.35 mg/g, 70.98 ± 0.03 mg/g, 21.31 ± 0.01 mg/g, and 18.45 ± 0.003 mg/g as gallic acid equivalent, respectively. Crude extract, methanol extract, ethyl acetate extract and n-hexane extract showed total flavonoids 26.87 ± 0.01 mg/g, 21.08 ± 0.03 mg/g, 21.70 ± 0.001 mg/g, 14.95 ± 0.02 mg/g as rutin equivalent. FTIR spectra of four extracts were comparable and showed the presence of nitro compounds and ring aromatic compounds. Our results indicate the potential of exploiting Hibiscus Rosa Sinensis leaves as a source of chemotherapeutic compounds, and it is worthy doing further researches on isolated bioactive compounds for developing novel functional foods or new drugs.

Broad anti-herpesviral activity of α-hydroxytropolones

Herpesviruses are ubiquitous in animals and cause economic losses concomitant with many diseases. Most of the domestic animal herpesviruses are within the subfamily Alphaherpesvirinae, which includes human herpes simplex virus 1 (HSV-1). Suppression of HSV-1 replication has been reported with α-hydroxytropolones (αHTs), aromatic ring compounds that have broad bioactivity due to potent chelating activity. It is postulated that αHTs inhibit enzymes within the nucleotidyltransferase superfamily (NTS). These enzymes require divalent cations for nucleic acid cleavage activity. Potential targets include the nuclease component of the herpesvirus terminase (pUL15C), a highly conserved NTS-like enzyme that cleaves viral DNA into genomic lengths prior to packaging into capsids. Inhibition of pUL15C activity in biochemical assays by various αHTs previously revealed a spectrum of potencies. Interestingly, the most potent anti-pUL15C αHT inhibited HSV-1 replication to a limited extent in cell culture. The aim of this study was to evaluate three different αHT molecules with varying biochemical anti-pUL15C activity for a capacity to inhibit replication of veterinary herpesviruses (BoHV-1, EHV-1, and FHV-1) and HSV-1. Given the known discordant potencies between anti-pUL15C and HSV-1 replication inhibition, a second objective was to elucidate the mechanism of action of these compounds. The results show that αHTs broadly inhibit herpesviruses, with similar inhibitory effect against HSV-1, BoHV-1, EHV-1, and FHV-1. Based on immunoblotting, Southern blotting, and real-time qPCR, the compounds were found to specifically inhibit viral DNA replication. Thus, αHTs represent a new class of broadly active anti-herpesviral compounds with potential veterinary applications.

Aromatic fuel oils produced from the pyrolysis-catalysis of polyethylene plastic with metal-impregnated zeolite catalysts

Pyrolysis-catalysis of high density polyethylene (HPDE) was carried out in a fixed bed, two stage reactor for the production of upgraded aromatic pyrolysis oils. The catalysts investigated were Y-zeolite impregnated with transition metal promoters with 1 wt% and 5 wt% metal loading of Ni, Fe, Mo, Ga, Ru and Co to determine the influence on aromatic fuel composition. Pyrolysis of the HDPE took place at 600 °C in the first stage of the reactor system and the evolved pyrolysis gases were passed to the second stage catalytic reactor, which had been pre-heated to 600 °C. Loading of metals on the Y-zeolite catalyst led to a higher production of aromatic hydrocarbons in the product oil with greater concentration of single ring aromatic hydrocarbons produced. The single ring aromatic compounds consisted of mainly toluene, ethylbenzene and xylenes, while the 2-ring hydrocarbons were mainly naphthalene and their alkylated derivatives. There was a reduction in the production of multiple ring aromatic compounds such as, phenanthrene and pyrene. The addition of the promoter metals appeared to have only a small influence on aromatic oil content, but increased the hydrogen yield from the HDPE. However, there was significant carbon deposition on the catalysts in the range 14–22 wt% for the 1% metal-Y-zeolite catalysts and increased to 18–26 wt% for the 5 wt% metal-Y-zeolite catalysts.

Biodegradation of alkaline lignin by Bacillus ligniniphilus L1

BackgroundLignin is the most abundant aromatic biopolymer in the biosphere and it comprises up to 30% of plant biomass. Although lignin is the most recalcitrant component of the plant cell wall, still there are microorganisms able to decompose it or degrade it. Fungi are recognized as the most widely used microbes for lignin degradation. However, bacteria have also been known to be able to utilize lignin as a carbon or energy source. Bacillus ligniniphilus L1 was selected in this study due to its capability to utilize alkaline lignin as a single carbon or energy source and its excellent ability to survive in extreme environments.ResultsTo investigate the aromatic metabolites of strain L1 decomposing alkaline lignin, GC–MS analysis was performed and fifteen single phenol ring aromatic compounds were identified. The dominant absorption peak included phenylacetic acid, 4-hydroxy-benzoicacid, and vanillic acid with the highest proportion of metabolites resulting in 42%. Comparison proteomic analysis was carried out for further study showed that approximately 1447 kinds of proteins were produced, 141 of which were at least twofold up-regulated with alkaline lignin as the single carbon source. The up-regulated proteins contents different categories in the biological functions of protein including lignin degradation, ABC transport system, environmental response factors, protein synthesis, assembly, etc.ConclusionsGC–MS analysis showed that alkaline lignin degradation of strain L1 produced 15 kinds of aromatic compounds. Comparison proteomic data and metabolic analysis showed that to ensure the degradation of lignin and growth of strain L1, multiple aspects of cells metabolism including transporter, environmental response factors, and protein synthesis were enhanced. Based on genome and proteomic analysis, at least four kinds of lignin degradation pathway might be present in strain L1, including a Gentisate pathway, the benzoic acid pathway and the β-ketoadipate pathway. The study provides an important basis for lignin degradation by bacteria.

Synergistic Effects of n-Hexane Fraction of Parkia biglobosa (Jacq.) Bark Extract and Selected Antibiotics on Bacterial Isolates

The incidence of resistance to commonly used antimicrobial agents by microbial pathogens demands increased effort in the development of effective ways of treating infections and diseases. The n-hexane fraction of lyophilized crude bark extract of Parkia biglobosa (Jacq.) was prepared and, in combination with selected antibiotics, assayed for antimicrobial activity against some selected bacterial pathogens using time-kill assay. Protein leakage analysis of the combined agents was performed using Bradford protein quantification method. Determination of active compounds present in the n-hexane fraction was done using Fourier Transform Infrared Spectroscopy (FTIR). While time-kill assay detected 43.33% synergy; 56.67% indifference and no antagonism at 1/2 × minimum inhibitory concentration (MIC), 1 × MIC exhibited 55% synergy, 45% indifference and no antagonism. Protein leakages from the cells of selected bacteria ranged from 1.20 µg/mL to 256.93 µg/mL. The presence of a phenyl group, an aromatic ring and phenolic compounds in the n-hexane fraction was confirmed at 2162 cm−1–2020 cm−1, 1605 cm−1–1533 cm−1 and 1438 cm−1–1444 cm−1 spectra peaks, respectively. The observed antibiotic−n-hexane fraction synergistic interaction revealed the improved antibacterial activity of the selected antibiotics. Hence, exploration of a combination of antibiotics with plant secondary metabolites is hereby advocated in the global quest for means of combating infectious diseases caused by multidrug-resistant pathogens.

열분해잔사유로부터 불균일계 불소화공정에 의해 제조된 메조페이스 피치의 특성

In this study, we have prepared mesophase pitch from pyrolysis fuel oil (PFO) by heterogeneous reforming process. This process was conducted by direct fluorination at various temperature and followed by the heat treatment at 390 ℃. The re- formed pitch was then investigated by softening point analysis, elemental analysis, fourier-transform infrared spectroscopy, high resolution X-ray diffraction and polarization microscope analysis. Carbon contents of reformed pitch increased according to increasing the reaction temperature of fluorination, while oxygen, nitrogen and sulfur contents were completely eliminated. As the fluorination temperature increased, the creation, growth, coalescence and alignment process of mesophase spheres were observed. Also the interlayer spacing of carbon hexagonal planar structure decreased, while its crystalline size increased. In addition, aromatic ring compound contents increased by the condensation polymerization of aliphatic compound. These results can be attributed to the radical reactivity of the fluorine increased as the reaction temperature increased. It was considered that the fluorination reaction could help PFO to generate aromatic compounds, via promoting polymerization by radical reaction.