Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.453
Filtrar
1.
Int J Mol Sci ; 25(13)2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-39000077

RESUMEN

Alkoxyalkylation and hydroxyalkylation methods utilizing oxo-compound derivatives such as aldehydes, acetals or acetylenes and various alcohols or water are widely used tools in preparative organic chemistry to synthesize bioactive compounds, biosensors, supramolecular compounds and petrochemicals. The syntheses of such molecules of broad relevance are facilitated by acid, base or heterogenous catalysis. However, degradation of the N-analogous Mannich bases are reported to yield alkoxyalkyl derivatives via the retro-Mannich reaction. The mutual derivative of all mentioned species are quinone methides, which are reported to form under both alkoxy- and aminoalkylative conditions and via the degradation of the Mannich-products. The aim of this review is to summarize the alkoxyalkylation (most commonly alkoxymethylation) of electron-rich arenes sorted by the methods of alkoxyalkylation (direct or via retro-Mannich reaction) and the substrate arenes, such as phenolic and derived carbocycles, heterocycles and the widely examined indole derivatives.


Asunto(s)
Electrones , Alquilación , Alcoholes/química , Catálisis , Hidrocarburos Aromáticos/química
2.
Microb Biotechnol ; 17(6): e14514, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38923400

RESUMEN

Pyruvate dehydrogenase (PDH) catalyses the irreversible decarboxylation of pyruvate to acetyl-CoA, which feeds the tricarboxylic acid cycle. We investigated how the loss of PDH affects metabolism in Pseudomonas putida. PDH inactivation resulted in a strain unable to utilize compounds whose assimilation converges at pyruvate, including sugars and several amino acids, whereas compounds that generate acetyl-CoA supported growth. PDH inactivation also resulted in the loss of carbon catabolite repression (CCR), which inhibits the assimilation of non-preferred compounds in the presence of other preferred compounds. Pseudomonas putida can degrade many aromatic compounds, most of which produce acetyl-CoA, making it useful for biotransformation and bioremediation. However, the genes involved in these metabolic pathways are often inhibited by CCR when glucose or amino acids are also present. Our results demonstrate that the PDH-null strain can efficiently degrade aromatic compounds even in the presence of other preferred substrates, which the wild-type strain does inefficiently, or not at all. As the loss of PDH limits the assimilation of many sugars and amino acids and relieves the CCR, the PDH-null strain could be useful in biotransformation or bioremediation processes that require growth with mixtures of preferred substrates and aromatic compounds.


Asunto(s)
Represión Catabólica , Pseudomonas putida , Complejo Piruvato Deshidrogenasa , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Pseudomonas putida/enzimología , Complejo Piruvato Deshidrogenasa/metabolismo , Complejo Piruvato Deshidrogenasa/genética , Hidrocarburos Aromáticos/metabolismo , Biodegradación Ambiental , Acetilcoenzima A/metabolismo , Ácido Pirúvico/metabolismo , Eliminación de Gen , Redes y Vías Metabólicas/genética
3.
Biosensors (Basel) ; 14(6)2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38920616

RESUMEN

Optical sensors, especially fluorescence sensors, have been widely used because of their advantages in sensing, such as the high sensitivity, good selectivity, no radiation source, and easy operation. Here, we report an example of fluorescence sensing based on two-dimensional (2D) covalent organic polymers and highlight that the material can achieve a fast response and multi-signal output. This 2DPTPAK+TAPB-based sensor can quickly detect aromatic hydrocarbons and Fe3+ by the fluorescence signal or electrical resistance signal.


Asunto(s)
Polímeros , Polímeros/química , Técnicas Biosensibles , Hidrocarburos Aromáticos/análisis , Colorantes Fluorescentes , Espectrometría de Fluorescencia
4.
Anal Chim Acta ; 1312: 342788, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38834273

RESUMEN

BACKGROUND: Mineral oil aromatic hydrocarbon (MOAH) analysis in foods is a major analytical challenge. Quantification is associated with a high uncertainty. The sources of uncertainty are multiple, but the major one is related to data interpretation and integration, which is partially derived from insufficiently efficient sample preparation. Recently, an updated ISO method for the analysis of mineral oil in fats and oils and a standard operating procedure for infant formula analysis have been published. Both methods reported significantly different (up to 1.25) distributions of the internal standards used for quantification (i.e., tri-tert-butyl benzene (TBB) and 2-methyl naphthalene (2-MN)) over the different solvent phases used in the saponification step. RESULTS: In this work, a microwave-assisted saponification and extraction method was optimized for MOAH analysis to solve the problem related to the MOAH internal standards partition. The paper examines the impact of the solvent mixture used, the concentration of KOH on the partition of TBB and 2-MN, and the effect of the matrix and the washing step to extract the unsaponifiable fraction containing the mineral oils. SIGNIFICANCE: The optimized procedure achieved a TBB/2-MN ratio of 1.05 ± 0.01 tested in five different fats and oils, namely, sunflower, rapeseed, coconut, palm, and extra virgin olive oils. The method can significantly contribute to reducing the uncertainty of the MOAH quantification when saponification is applied.


Asunto(s)
Microondas , Hidrocarburos Aromáticos/análisis , Aceite Mineral/análisis , Aceite Mineral/química
5.
Environ Sci Technol ; 58(20): 8792-8802, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38719742

RESUMEN

Per- and polyfluoroalkyl substances (PFASs) from aqueous film forming foams (AFFFs) can hinder bioremediation of co-contaminants such as trichloroethene (TCE) and benzene, toluene, ethylbenzene, and xylene (BTEX). Anaerobic dechlorination can require bioaugmentation of Dehalococcoides, and for BTEX, oxygen is often sparged to stimulate in situ aerobic biodegradation. We tested PFAS inhibition to TCE and BTEX bioremediation by exposing an anaerobic TCE-dechlorinating coculture, an aerobic BTEX-degrading enrichment culture, and an anaerobic toluene-degrading enrichment culture to n-dimethyl perfluorohexane sulfonamido amine (AmPr-FHxSA), perfluorohexane sulfonamide (FHxSA), perfluorohexanesulfonic acid (PFHxS), or nonfluorinated surfactant sodium dodecyl sulfate (SDS). The anaerobic TCE-dechlorinating coculture was resistant to individual PFAS exposures but was inhibited by >1000× diluted AFFF. FHxSA and AmPr-FHxSA inhibited the aerobic BTEX-degrading enrichment. The anaerobic toluene-degrading enrichment was not inhibited by AFFF or individual PFASs. Increases in amino acids in the anaerobic TCE-dechlorinating coculture compared to the control indicated stress response, whereas the BTEX culture exhibited lower concentrations of all amino acids upon exposure to most surfactants (both fluorinated and nonfluorinated) compared to the control. These data suggest the main mechanisms of microbial toxicity are related to interactions with cell membrane synthesis as well as protein stress signaling.


Asunto(s)
Biodegradación Ambiental , Hidrocarburos Aromáticos , Hidrocarburos Aromáticos/metabolismo , Tricloroetileno/metabolismo , Sulfonamidas/metabolismo
6.
Chemosphere ; 361: 142490, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38821131

RESUMEN

Aromatic hydrocarbons like benzene, toluene, xylene, and ethylbenzene (BTEX) can escape into the environment from oil and gas operations and manufacturing industries posing significant health risks to humans and wildlife. Unlike conventional clean-up methods used, biological approaches such as bioremediation can provide a more energy and labour-efficient and environmentally friendly option for sensitive areas such as nature reserves and cities, protecting biodiversity and public health. BTEX contamination is often concentrated in the subsurface of these locations where oxygen is rapidly depleted, and biodegradation relies on anaerobic processes. Thus, it is critical to understand the anaerobic biodegradation characteristics as it has not been explored to a major extent. This review presents novel insights into the degradation mechanisms under anaerobic conditions and presents a detailed description and interconnection between them. BTEX degradation can follow four activation mechanisms: hydroxylation, carboxylation, methylation, and fumarate addition. Hydroxylation is one of the mechanisms that explains the transformation of benzene into phenol, toluene into benzyl alcohol or p-cresol, and ethylbenzene into 1-phenylethanol. Carboxylation to benzoate is thought to be the primary mechanism of degradation for benzene. Despite being poorly understood, benzene methylation has been also reported. Moreover, fumarate addition is the most widely reported mechanism, present in toluene, ethylbenzene, and xylene degradation. Further research efforts are required to better elucidate new and current alternative catabolic pathways. Likewise, a comprehensive analysis of the enzymes involved as well as the development of advance tools such as omic tools can reveal bottlenecks degradation steps and create more effective on-site strategies to address BTEX pollution.


Asunto(s)
Derivados del Benceno , Benceno , Biodegradación Ambiental , Tolueno , Xilenos , Anaerobiosis , Derivados del Benceno/metabolismo , Benceno/metabolismo , Tolueno/metabolismo , Xilenos/metabolismo , Contaminantes Ambientales/metabolismo , Hidrocarburos Aromáticos/metabolismo
7.
Lett Appl Microbiol ; 77(5)2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38650069

RESUMEN

Environmental pollution with aromatic and aliphatic hydrocarbons caused by oil and petrochemical industries has very toxic and carcinogenic effects on living organisms and should be removed from the environment. In this research, after analyzing the oil sludge of the Bahregan area, it was found that most aliphatic paraffin compounds are related to octadecane, most liquid aliphatic compounds are related to hexadecane, and most aromatic compounds are related to naphthalene, phenanthrene, fluoranthene, and anthracene. Then, we investigated the ability of native bacteria from this area, such as Thalassospira, Chromohalobacter, and a bacterial consortium, to biodegrade the dominant aromatic and aliphatic hydrocarbons found in oil sludge. The results of Gas Chromatography-Mass Spectrometry analysis showed that among the tested hydrocarbon sources, Thalassospira can completely remove octadecane and hexadecane, and Chromohalobacter can reduce hexadecane from 15.9 to 9.9%. The bacterial consortium can completely remove octadecane and reduce hexadecane from 15.9 to 5.1%, toluene from 25.6 to 0.6%, and phenanthrene from 12.93 to 6%. According to the obtained results, the bacterial consortium effectively plays a role in the biodegradation of aromatic and aliphatic hydrocarbons, making it a viable solution for treating hydrocarbon pollutants in various environments.


Asunto(s)
Bacterias , Biodegradación Ambiental , Hidrocarburos Aromáticos , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/aislamiento & purificación , Bacterias/genética , Hidrocarburos Aromáticos/metabolismo , Alcanos/metabolismo , Aguas del Alcantarillado/microbiología , Fenantrenos/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Petróleo/metabolismo , Petróleo/microbiología , Consorcios Microbianos
8.
Chem Biodivers ; 21(6): e202400150, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38548660

RESUMEN

Experiments were conducted in this study on the co-hydropyrolysis of three components of biomass (cellulose, hemicellulose, and lignin) and HDPE by using SR-Pd/Trap-HZ-5 as catalyst. To control the variable, we use the same experiment conditions in co-hydropyrolysis: Si/Al ratio of 50, Pd load 1 %, catalyst to reactant ratio of 1 : 10, 1 MPa, 400 °C, reaction time 1 h. Use XRD, TEM, BET, and NH3-TPD to confirm catalyst successful synthesis; use pine sawdust (PW) co-hydropyrolysis with HDPE to analyse catalytic activity; and use GC/MS to characterize the chemical composition of the bio-oil from the co-hydropyrolysis of biomass components and HDPE. The results show that cellulose has a significant synergistic effect with aromatic hydrocarbon production, whose selectivity was 93.3 %; hemicellulose has a synergistic effect; aromatic selectivity can reach 75.1 %; and a negative synergistic effect between lignin and HDPE was shown as the selectivity of aromatic hydrocarbons decreased from 62.1 % to 15.6 %.


Asunto(s)
Biomasa , Celulosa , Hidrocarburos Aromáticos , Polisacáridos , Pirólisis , Zeolitas , Catálisis , Hidrocarburos Aromáticos/química , Polisacáridos/química , Celulosa/química , Zeolitas/química , Lignina/química
9.
Molecules ; 29(6)2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38542825

RESUMEN

Roasting is an important step in the pretreatment of biomass upgrading. Roasting can improve the fuel quality of biomass, reduce the O/C and H/C ratios in the biomass, and provide the biomass with a fuel quality comparable to that of lignite. Therefore, studying the structure and component evolution laws during biomass roasting treatment is important for the rational and efficient utilization of biomass. When the roasting temperature is 200-300 °C, the cellulose and hemicellulose in the biomass undergo a depolymerization reaction, releasing many monocyclic aromatic hydrocarbons with high reactivity. The proportion of monocyclic aromatic hydrocarbons in biomass roasting products can be effectively regulated by controlling the reaction temperature, residence time, catalyst, baking atmosphere, and other factors in the biomass roasting process. This paper focuses on the dissociation law of organic components in the pretreatment process of biomass roasting.


Asunto(s)
Calor , Hidrocarburos Aromáticos , Biomasa , Hidrocarburos Aromáticos/química , Temperatura , Celulosa , Hidrocarburos
10.
Environ Sci Pollut Res Int ; 31(12): 18785-18796, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38349495

RESUMEN

Recovering renewable chemicals from de-fatted microalgal residue derived from lipid extraction within the algal-derived biofuel sector is crucial, given the rising significance of microalgal-derived biodiesel as a potential substitute for petroleum-based liquid fuels. As a circular economy strategy, effective valorization of de-fatted biomass significantly improves the energetic and economic facets of establishing a sustainable algal-derived biofuel industry. In this scenario, this study investigates flash catalytic pyrolysis as a sustainable pathway for valorizing Scenedesmus sp. post-extraction residue (SPR), potentially yielding a bio-oil enriched with upgraded characteristics, especially renewable aromatic hydrocarbons. In the scope of this study, volatile products from catalytic and non-catalytic flash pyrolysis were characterized using a micro-furnace type temperature programmable pyrolyzer coupled with gas chromatographic separation and mass spectrometry detection (Py-GC/MS). Flash pyrolysis of SPR resulted in volatile products with elevated oxygen and nitrogen compounds with concentrations of 46.4% and 26.4%, respectively. In contrast, flash pyrolysis of lyophilized microalgal biomass resulted in lower concentrations of these compounds, with 40.9% oxygen and 17.3% nitrogen. Upgrading volatile pyrolysis products from SPR led to volatile products comprised of only hydrocarbons, while completely removing oxygen and nitrogen-containing compounds. This was achieved by utilizing a low-cost HZSM-5 catalyst within a catalytic bed at 500 °C. Catalytic experiments also indicate the potential conversion of SPR into a bio-oil rich in monocyclic aromatic hydrocarbons, primarily BETX, with toluene comprising over one-third of its composition, thus presenting a sustainable pathway for producing an aromatic hydrocarbon-rich bio-oil derived from SPR. Another significant finding was that 97.8% of the hydrocarbon fraction fell within the gasoline range (C5-C12), and 35.5% fell within the jet fuel range (C8-C16). Thus, flash catalytic pyrolysis of SPR exhibits significant promise for application in drop-in biofuel production, including green gasoline and bio-jet fuel, aligning with the principles of the circular economy, green chemistry, and bio-refinery.


Asunto(s)
Hidrocarburos Aromáticos , Aceites de Plantas , Polifenoles , Scenedesmus , Scenedesmus/metabolismo , Pirólisis , Gasolina , Biocombustibles , Calor , Cromatografía de Gases y Espectrometría de Masas , Hidrocarburos/química , Catálisis , Nitrógeno , Oxígeno , Biomasa
11.
Appl Microbiol Biotechnol ; 108(1): 189, 2024 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-38305872

RESUMEN

Bacterial strains of the genera Arthrobacter, Bacillus, Dietzia, Kocuria, and Micrococcus were isolated from oil-contaminated soils of the Balgimbaev, Dossor, and Zaburunye oil fields in Kazakhstan. They were selected from 1376 isolated strains based on their unique ability to use crude oil and polyaromatic hydrocarbons (PAHs) as sole source of carbon and energy in growth experiments. The isolated strains degraded a wide range of aliphatic and aromatic components from crude oil to generate a total of 170 acid metabolites. Eight metabolites were detected during the degradation of anthracene and of phenanthrene, two of which led to the description of a new degradation pathway. The selected bacterial strains Arthrobacter bussei/agilis SBUG 2290, Bacillus atrophaeus SBUG 2291, Bacillus subtilis SBUG 2285, Dietzia kunjamensis SBUG 2289, Kocuria rosea SBUG 2287, Kocuria polaris SBUG 2288, and Micrococcus luteus SBUG 2286 promoted the growth of barley shoots and roots in oil-contaminated soil, demonstrating the enormous potential of isolatable and cultivable soil bacteria in soil remediation. KEY POINTS: • Special powerful bacterial strains as potential crude oil and PAH degraders. • Growth on crude oil or PAHs as sole source of carbon and energy. • Bacterial support of barley growth as resource for soil remediation.


Asunto(s)
Hordeum , Hidrocarburos Aromáticos , Petróleo , Contaminantes del Suelo , Petróleo/microbiología , Yacimiento de Petróleo y Gas , Hordeum/metabolismo , Contaminantes del Suelo/metabolismo , Hidrocarburos Aromáticos/metabolismo , Bacillus subtilis/metabolismo , Carbono/metabolismo , Suelo , Biodegradación Ambiental , Microbiología del Suelo , Hidrocarburos/metabolismo
12.
Bioresour Technol ; 398: 130472, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38387841

RESUMEN

As toxic contaminants, aromatic compounds are widespread in most environmental matrices, and bioenzymatic catalysis plays a critical role in the degradation of xenobiotics. Here, a thermophillic aromatic hydrocarbon degrader Aeribacillus pallidus HB-1 was found. Bioinformatic analysis of the HB-1 genome revealed two ring-cleaving extradiol dioxygenases (EDOs), among which, EDO-0418 was assigned to a new subfamily of type I.1 EDOs and exhibited a broad substrate specificity, particularly towards biarylic substrate. Both EDOs exhibited optimal activities at elevated temperatures (55 and 65 °C, respectively) and showed remarkable thermostability, pH stability, metal ion resistance and tolerance to chemical reagents. Most importantly, simulated wastewater bioreactor experiments demonstrated efficient and uniform degradation performance of mixed aromatic substrates under harsh environments by the two enzymes combined for potential industrial applications. The unveiling of two thermostable dioxygenases with broad substrate specificities and stress tolerance provides a novel approach for highly efficient environmental bioremediation using composite enzyme systems.


Asunto(s)
Bacillaceae , Dioxigenasas , Hidrocarburos Aromáticos , Dioxigenasas/genética , Dioxigenasas/química , Dioxigenasas/metabolismo , Hidrocarburos Aromáticos/metabolismo , Metales
13.
Arch Microbiol ; 206(3): 98, 2024 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-38351169

RESUMEN

Hydrocarbons are considered as one of the most common and harmful environmental pollutants affecting human health and the environment. Bioremediation as an environmentally friendly, highly efficient, and cost-effective method in remediating oil-contaminated environments has been interesting in recent decades. In this study, hydrocarbon degrader bacterial strains were isolated from the highly petroleum-contaminated soils in the Dehloran oil field in the west of Iran. Out of 37 isolates, 15 can grow on M9 agar medium that contains 1.5 g L-1 of crude oil as the sole carbon source. The morphological, biochemical, and 16SrRNA sequencing analyses were performed for the isolates. The choosing of the isolates as the hydrocarbon degrader was examined by evaluating the efficacy of their crude oil removal at a concentration of 10 g L-1 in an aqueous medium. The results showed that five isolates belonging to Pseudomonas sp., Pseudomonas oryzihabitans, Roseomonas aestuarii, Pantoea agglomerans, and Arthrobacter sp. had a hyper hydrocarbon-degrading activity and they could remove more than 85% of the total petroleum hydrocarbon (TPH) after 96 h. The highest TPH removal of about 95.75% and biodegradation rate of 0.0997 g L-1 h-1 was observed for P. agglomerans. The gas chromatography-mass spectroscopy (GC-MS) analysis was performed during the biodegradation process by P. agglomerans to detect the degradation intermediates and final products. The results confirmed the presence of intermediates such as alcohols and fatty acids in the terminal oxidation pathway of alkanes in this biodegradation process. A promising P. agglomerans NB391 strain can remove aliphatic and aromatic hydrocarbons simultaneously.


Asunto(s)
Hidrocarburos Aromáticos , Pantoea , Petróleo , Contaminantes del Suelo , Humanos , Pantoea/genética , Pantoea/metabolismo , Petróleo/metabolismo , Irán , Contaminantes del Suelo/metabolismo , Hidrocarburos/metabolismo , Biodegradación Ambiental , Suelo/química , Microbiología del Suelo
15.
J Chromatogr A ; 1715: 464600, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38176352

RESUMEN

An automated implementation for a subfractionation of mineral oil aromatic hydrocarbons (MOAH) into a mono-/di-aromatic fraction (MDAF) and a tri-/poly-aromatic fraction (TPAF) is presented, which is highly demanded by the European Food Safety Authority (EFSA) respecting the genotoxic and carcinogenic potential of MOAH. For this, donor-acceptor-complex chromatography (DACC) was used as a selective stationary phase to extend the conventional instrumental setup for the analysis of mineral oil hydrocarbons via on-line coupled liquid chromatography-gas chromatography-flame ionization detection (LC-GC-FID). A set of six new internal standards was introduced for the verification of the MOAH fractionation and a quantification of MDAF and TPAF, respectively. The automated DACC approach was applied to representative petrochemical references as well as to food samples, such as rice and infant formula, generally showing well conformity with results obtained by state-of-the-art analysis using two-dimensional GC (GCxGC). Relative deviations of DACC/LC-GC-FID compared to GCxGC-FID methods regarding the ≥ 3 ring MOAH content ranged between -50 and +6 % (median: -2 %, all samples, only values above limit of quantification). However, crucial deviations mainly result from "border-crossing" substances, e.g., dibenzothiophenes or partially hydrogenated MOAH. These substances can cause overestimations of ≥ 3 ring MOAH fraction during GCxGC analysis due to co-elution, which is mostly avoided using the DACC approach. Furthermore, the DACC approach can help to minimize underestimations of toxicologically relevant ≥ 3 ring MOAH caused by an unavoidable loss of MOAH during epoxidation, since natural olefins, such as terpenes, predominantly elute in MDAF, which was exemplarily shown for an olive oil and a terpene reference. The presented approach can be implemented easily in existing LC-GC-FID setup for an automated and advanced screening of MOAH to lower the need for elaborate GCxGC analysis also in routine environments.


Asunto(s)
Hidrocarburos Aromáticos , Aceite Mineral , Humanos , Aceite Mineral/análisis , Contaminación de Alimentos/análisis , Hidrocarburos Aromáticos/análisis , Cromatografía de Gases/métodos , Cromatografía Liquida/métodos , Hidrocarburos/análisis , Terpenos/análisis
16.
Artículo en Inglés | MEDLINE | ID: mdl-38180316

RESUMEN

A Gram-stain-negative strain, designated as D2M1T was isolated from xylene-degrading enrichment culture and characterized using a polyphasic approach to determine its taxonomic position. The 16S rRNA gene sequence analysis revealed that strain D2M1T belongs to the genus Acidovorax, with the highest 16S rRNA gene similarity to Acidovorax delafieldii DSM 64T (99.93 %), followed by Acidovorax radicis DSM 23535T (98.77 %) and Acidovorax kalamii MTCC 12652T (98.76 %). The draft genome sequence of strain D2M1T is 5.49 Mb long, and the G+C content of the genome is 64.2 mol%. Orthologous average nucleotide identity and digital DNA-DNA hybridization relatedness values between strain D2M1T and its closest relatives were below the threshold values for species demarcation confirming that strain D2M1T is distinctly separated from its closest relatives. The whole genome analysis of the strain revealed a phenol degradation gene cluster, encoding a multicomponent phenol hydroxylase (mPH) together with a complete meta-cleavage pathway including an I.2.C-type catechol 2,3-dioxygenase (C23O) gene. The strain was able to degrade benzene and ethylbenzene as sole sources of carbon and energy under aerobic and microaerobic conditions. Cells were facultatively aerobic rods and motile with a single polar flagellum. The predominant fatty acids (>10 % of the total) of strain D2M1T were summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The major ubiquinone of strain D2M1T was Q8, while the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Based on polyphasic data, it is concluded that strain D2M1T represents a novel species of the genus Acidovorax, for which the name of Acidovorax benzenivorans sp. nov. is proposed. The type strain of the species is strain D2M1T (=DSM 115238T=NCAIM B.02679T).


Asunto(s)
Hidrocarburos Aromáticos , Xilenos , ARN Ribosómico 16S/genética , Composición de Base , Ácidos Grasos/química , Filogenia , Análisis de Secuencia de ADN , ADN Bacteriano/genética , Técnicas de Tipificación Bacteriana , Bacterias
17.
J Environ Manage ; 351: 119630, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38043308

RESUMEN

In order to obtain extended storage life of food-grade materials and better barrier properties against environmental factors, a multilayer plastic packaging (MLP) is often used. The multilayer packaging plastics are labelled as "other" (SPI#7) category, and are manufactured with a combination of barrier plastics, rigid plastics and printing surface. Owing to their complex composition and difficulty in separating the layers of MLP, its mechanical recycling is challenging. In this study, MLP wastes (MLPWs) were collected from zero-waste garbage collection center of IIT Madras, India, and thoroughly characterized to determine their composition and plastic types. MLPWs were characterized using various physico-chemical methods such as thermogravimetric/differential scanning calorimetric analysis, Fourier transform infrared spectroscopy, bomb calorimetry, and proximate and ultimate analyses. The MLPWs were mainly made up of polyethylene (PE) and polyethylene terephthalate (PET). Further, the non-catalytic and zeolite-catalyzed fast pyrolysis of these MLPWs were studied using analytical pyrolysis coupled with gas chromatograph/mass spectrometer (Py-GC/MS). The non-catalytic fast pyrolysis of MLPWs primarily produced a mixture of aliphatic and alicyclic hydrocarbons, while zeolite catalyzed fast pyrolysis resulted in the formation of mono-aromatic hydrocarbons (MAHs). The activity of HZSM-5, zeolite Y (HY) and zeolite beta (Hß) catalysts were evaluated, and the salient products were quantified. The yields of MAHs like benzene, toluene, ethylbenzene and xylene using the zeolites followed the trend: HZSM-5 (14.9 wt%) > HY (8.1 wt%) > Hß (7.8 wt%), at 650 °C. The use of HZSM-5 resulted in highest yield of MAHs, viz. 16.1 wt%, at the optimum temperature of 550 °C and MLPW-to-catalyst ratio of 1:15 (w/w). The superior activity of HZSM-5 is due to its nominal acidity and larger pore size of 4.24 nm, as compared to HY and Hß. The MAHs yield from three other types of MLPWs varied in the range of 9-16 wt%. The present study demonstrates a promising pathway for the catalytic upcycling of highly heterogeneous MLPWs in the context of circular economy.


Asunto(s)
Hidrocarburos Aromáticos , Zeolitas , Zeolitas/química , India , Hidrocarburos/análisis , Hidrocarburos Aromáticos/análisis , Catálisis , Tolueno , Calor
18.
J Chromatogr A ; 1713: 464525, 2024 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-38000198

RESUMEN

Lubricating oils help an internal combustion engine function effectively by reducing friction and wear on the engine's moving parts. They typically consist of petroleum-derived base oil and various additives to achieve the desired characteristics in automotive engine oils. Determination of aromatics and polar additives in the finished and used lubricating oils is not possible with existing methods hence their development is significant from the perspectives of environment and reuse/re-refining of used lubricating oils. This study reports the development of a new HPLC method to determine additives in the finished lubricating oils and/or polars in the used engine oils. The proposed method is simple, fast (runtime of 13 min), does not require sample pre-treatment, and exhibits high precision and superior limits of detection and quantification. The method demonstrated good linear response ranging from 0.1 to 30 mass for total aromatics and 0.1 to 20 % for additives. The method validation was carried out by analyzing brand-new commercial two and four-wheeler lubricants with used automotive lubricants. Based on the proposed method, the aromatics and additives concentration ranges in the studied finished lubricants were estimated between 0.20-1.70 % (mass) and 0.20-3.50 % (mass), respectively. Similarly, for used lubricants, the aromatics and additives were estimated to be 1.00-6.10 % and 0.60-2.40 % (mass), respectively.


Asunto(s)
Hidrocarburos Aromáticos , Petróleo , Cromatografía Líquida de Alta Presión , Aceites , Petróleo/análisis , Lubricantes/análisis , Lubricantes/química
19.
Environ Res ; 245: 118076, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38160977

RESUMEN

Owing to the ever-increasing generation of plastic waste, the need to develop environmentally friendly disposal methods has increased. This study explored the potential of waste plastic straw to generate valuable light olefins and monocyclic aromatic hydrocarbons (MAHs) via catalytic pyrolysis using high-silica zeolite-based catalysts. HZSM-5 (SiO2/Al2O3:200) exhibited superior performance, yielding more light olefins (49.8 wt%) and a higher MAH content than Hbeta (300). This was attributed to the increased acidity and proper shape selectivity. HZSM-5 displayed better coking resistance (0.7 wt%) than Hbeta (4.4 wt%) by impeding secondary reactions, limiting coke precursor formation. The use of HZSM-5 (80) resulted in higher MAHs and lower light olefins than HZSM-5 (200) because of its higher acidity. Incorporation of Co into HZSM-5 (200) marginally lowered light olefin yield (to 44.0 wt%) while notably enhancing MAH production and boosting propene selectivity within the olefin composition. These observations are attributed to the well-balanced coexistence of Lewis and Brønsted acid sites, which stimulated the carbonium ion mechanism and induced H-transfer, cyclization, Diels-alder, and dehydrogenation reactions. The catalytic pyrolysis of plastic straw over high-silica and metal-loaded HZSM-5 catalysts has been suggested as an efficient and sustainable method for transforming plastic waste materials into valuable light olefins and MAHs.


Asunto(s)
Hidrocarburos Aromáticos , Zeolitas , Dióxido de Silicio , Pirólisis , Calor , Biomasa , Alquenos , Catálisis , Hidrocarburos
20.
Environ Toxicol Pharmacol ; 105: 104344, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38103810

RESUMEN

Two hundred and twenty subjects were recruited while undergoing cardiac catheterization. AHRR cg05575921 methylation was shown to be significantly decreased in ever smokers compared to never smokers (Mean± SD = 64.2 ± 17.2 vs 80.1 ± 11.1 respectively; P < 0.0001). In addition, higher urinary levels of 2-OHNAP and 2-OHFLU were significantly associated with more AHRR cg05575921 hypomethylation, even after correcting for smoking (ß[95%CI]= -4.161[-7.553, -0.769]; P = 0.016 and -5.190[-9.761, -0.618]; P = 0.026, respectively) but not 1-OHPYR (ß[95%CI]= -3.545 [-10.935, 3.845]; P = 0.345). Additionally, hypomethylation of AHRR ROI was significantly associated with obstructive coronary artery disease (CAD) after adjusting for smoking, age, sex, diabetes and dyslipidemia (OR [95%CI] = 1.024[1.000 - 1.048]; P = 0.046). Results of this study necessitate further validation to potentially consider clinical incorporation of AHRR methylation status as an early predictive biomarker for the potential association between ambient air pollution and CAD.


Asunto(s)
Contaminación del Aire , Enfermedad de la Arteria Coronaria , Hidrocarburos Aromáticos , Humanos , Enfermedad de la Arteria Coronaria/genética , Biomarcadores , Metilación de ADN , Proteínas Represoras/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA