scholarly journals Biodegradation of binary mixtures of octane with benzene, toluene, ethylbenzene or xylene (BTEX): insights on the potential of Burkholderia, Ralstonia, Pseudomonas, and Cupriavidus isolates

2021 ◽  
Author(s):  
Hernando P. Bacosa ◽  
Jhonamie Abiner Mabuhay-Omar ◽  
Rodulf Anthony T. Balisco ◽  
Dawin M. Omar ◽  
Chihiro Inoue
Keyword(s):  
Binary Mixtures ◽  
Aromatic Hydrocarbons ◽  
Bacterial Consortium ◽  
Final Concentration ◽  
Aliphatic Hydrocarbons ◽  
Alkane Hydroxylase ◽  
Benzene Toluene ◽  
Aliphatic And Aromatic Hydrocarbons ◽  
By Products ◽  
Btex Compounds

Abstract The contamination of the environment by crude oil and its by-products, which mainly composed of aliphatic and aromatic hydrocarbons, is a widespread problem. Biodegradation by bacteria is one of the processes responsible for the removal of these pollutants. This study was conducted to determine the abilities of Burkholderia sp. B5, Ralstonia sp. B1, Pseudomonas sp. T1, and Cupriavidus sp. X5 to degrade binary mixtures of octane (representing aliphatic hydrocarbons) with benzene, toluene, ethylbenzene, or xylene (BTEX as aromatic hydrocarbons) at a final concentration of 100 ppm under aerobic conditions. These strains were isolated from an enriched bacterial consortium (Yabase or Y consortium) that prefer to degrade aromatic hydrocarbon over aliphatic hydrocarbons. We found that B5 degraded all BTEX compounds more rapidly than octane. In contrast, B1, T1 and X5 utilized more of octane over BTX compounds. B5 also preferred to use benzene over octane with varying concentrations of up to 200 mg/l. B5 possesses alkane hydroxylase (alkB) and catechol 2,3-dioxygenase (C23D) genes, which are responsible for the degradation of alkanes and aromatic hydrocarbons, respectively. This study strongly supports our notion that Burkholderia played a key role in the preferential degradation of aromatic hydrocarbons over aliphatic hydrocarbons in the previously characterized Y consortium. The preferential degradation of more toxic aromatic hydrocarbons over aliphatics is crucial in risk-based bioremediation.

Excess Volumes of Mixtures of Alkanols with Aromatic Hydrocarbons

1993 ◽  
Vol 58 (11) ◽  
pp. 2612-2624 ◽  
Author(s):  
Petr Munk ◽  
Anwei Qin ◽  
Dolly E. Hoffman
Keyword(s):  
Aromatic Hydrocarbon ◽  
Benzene Ring ◽  
Binary Mixtures ◽  
Aromatic Hydrocarbons ◽  
Excess Volume ◽  
Excess Volumes ◽  
Compositional Dependence ◽  
Benzene Toluene

The excess volumes of twenty binary mixtures of four aromatic hydrocarbons (benzene, toluene, ethylbenzene, and p-xylene) and five linear alkanols (methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol) at 20 °C are reported. The excess volume of systems with the same alkanol increases with increasing size and number of substituents on the benzene ring. For systems with the same aromatic hydrocarbon it increases with the length of the alkanols. The dependence of ∆V/φ1ϑ2 values on composition is noticeably asymmetric. Systems with benzene as one of the component show larger ∆V/φ1ϑ2 values than other systems and systems with methanol show different compositional dependence patterns.

scholarly journals Direct cyanomethylation of aliphatic and aromatic hydrocarbons with acetonitrile over a metal loaded titanium oxide photocatalyst

2017 ◽  
Vol 7 (12) ◽  
pp. 2457-2466 ◽  
Author(s):  
Emiko Wada ◽  
Tomoaki Takeuchi ◽  
Yuki Fujimura ◽  
Akanksha Tyagi ◽  
Tatsuhisa Kato ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Aromatic Hydrocarbons ◽  
Aliphatic Hydrocarbons ◽  
Hybrid Catalyst ◽  
Aliphatic And Aromatic Hydrocarbons

The direct cyanomethylation of aliphatic hydrocarbons proceeds with a Pt/TiO2 photocatalyst, while that of benzene requires a Pd/TiO2 hybrid catalyst.

Excess molar volumes, speeds of sound, and isentropic compressibilities of binary mixtures of furfural with some aromatic hydrocarbons

1988 ◽  
Vol 66 (5) ◽  
pp. 1295-1298 ◽  
Author(s):  
Homendra Naorem ◽  
S. K. Suri
Keyword(s):  
Binary Mixtures ◽  
Aromatic Hydrocarbons ◽  
Excess Molar Volumes ◽  
Isentropic Compressibilities ◽  
Molar Excess ◽  
Geometric Factors ◽  
Volumes Of Mixing ◽  
Benzene Toluene ◽  
Molar Excess Volumes ◽  
Solution Behaviour

Molar excess volumes of mixing and isentropic compressibilities for the binary mixtures of furfural with benzene, toluene, ethylbenzene, and o-, m-, and p-xylenes at 308.15 K have been measured. The results reveal that geometric factors are predominant in determining the solution behaviour of the binary mixtures under investigation.

scholarly journals Metagenomic Insights into the Bacterial Functions of a Diesel-Degrading Consortium for the Rhizoremediation of Diesel-Polluted Soil

Genes ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 456 ◽  
Author(s):  
Daniel Garrido-Sanz ◽  
Miguel Redondo-Nieto ◽  
María Guirado ◽  
Oscar Pindado Jiménez ◽  
Rocío Millán ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Bacterial Consortium ◽  
Polluted Soil ◽  
Total Petroleum Hydrocarbons ◽  
Ring Cleavage ◽  
Rrna Gene ◽  
Initial Oxidation ◽  
Microbiome Composition ◽  
Genes Encoding ◽  
Aliphatic And Aromatic Hydrocarbons

Diesel is a complex pollutant composed of a mixture of aliphatic and aromatic hydrocarbons. Because of this complexity, diesel bioremediation requires multiple microorganisms, which harbor the catabolic pathways to degrade the mixture. By enrichment cultivation of rhizospheric soil from a diesel-polluted site, we have isolated a bacterial consortium that can grow aerobically with diesel and different alkanes and polycyclic aromatic hydrocarbons (PAHs) as the sole carbon and energy source. Microbiome diversity analyses based on 16S rRNA gene showed that the diesel-degrading consortium consists of 76 amplicon sequence variants (ASVs) and it is dominated by Pseudomonas, Aquabacterium, Chryseobacterium, and Sphingomonadaceae. Changes in microbiome composition were observed when growing on specific hydrocarbons, reflecting that different populations degrade different hydrocarbons. Shotgun metagenome sequence analysis of the consortium growing on diesel has identified redundant genes encoding enzymes implicated in the initial oxidation of alkanes (AlkB, LadA, CYP450) and a variety of hydroxylating and ring-cleavage dioxygenases involved in aromatic and polyaromatic hydrocarbon degradation. The phylogenetic assignment of these enzymes to specific genera allowed us to model the role of specific populations in the diesel-degrading consortium. Rhizoremediation of diesel-polluted soil microcosms using the consortium, resulted in an important enhancement in the reduction of total petroleum hydrocarbons (TPHs), making it suited for rhizoremediation applications.

Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

2017 ◽  
Vol 68 (1) ◽  
pp. 116-120
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
Lucian Mihail Birsa ◽  
Ioan Gabriel Sandu ◽  
Laura Gabriela Sarbu ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Metal Content ◽  
Pulse Method ◽  
Acid Strength ◽  
Strength Distribution ◽  
Zeolite Catalysts ◽  
Benzene Toluene ◽  
Acid Strength Distribution ◽  
Silver Cations ◽  
Heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

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