Selective dealkylation of alkyl polycyclic aromatic hydrocarbons towards innovative upgrading process of practical heavy oil

A silica-monolayer loaded on alumina with weak Brønsted acid sites and large pore size can selectively dealkylate alkyl polycyclic aromatics to long-chain alkanes and polycyclic aromatics for production of chemicals and fuel.

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CYP63A2, a Catalytically Versatile Fungal P450 Monooxygenase Capable of Oxidizing Higher-Molecular-Weight Polycyclic Aromatic Hydrocarbons, Alkylphenols, and Alkanes

Applied and Environmental Microbiology ◽

10.1128/aem.03767-12 ◽

2013 ◽

Vol 79 (8) ◽

pp. 2692-2702 ◽

Cited By ~ 60

Author(s):

Khajamohiddin Syed ◽

Aleksey Porollo ◽

Ying Wai Lam ◽

Paul E. Grimmett ◽

Jagjit S. Yadav

Keyword(s):

Molecular Weight ◽

Polycyclic Aromatic Hydrocarbons ◽

Substrate Specificity ◽

Crude Oil ◽

Aromatic Hydrocarbons ◽

Aliphatic Hydrocarbon ◽

Ligand Docking ◽

P450 Monooxygenase ◽

Polycyclic Aromatic ◽

Long Chain

ABSTRACTCytochrome P450 monooxygenases (P450s) are known to oxidize hydrocarbons, albeit with limited substrate specificity across classes of these compounds. Here we report a P450 monooxygenase (CYP63A2) from the model ligninolytic white rot fungusPhanerochaete chrysosporiumthat was found to possess a broad oxidizing capability toward structurally diverse hydrocarbons belonging to mutagenic/carcinogenic fused-ring higher-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs), endocrine-disrupting long-chain alkylphenols (APs), and crude oil aliphatic hydrocarbonn-alkanes. A homology-based three-dimensional (3D) model revealed the presence of an extraordinarily large active-site cavity in CYP63A2 compared to the mammalian PAH-oxidizing (CYP3A4, CYP1A2, and CYP1B1) and bacterial aliphatic-hydrocarbon-oxidizing (CYP101D and CYP102A1) P450s. This structural feature in conjunction with ligand docking simulations suggested potential versatility of the enzyme. Experimental characterization using recombinantly expressed CYP63A2 revealed its ability to oxidize HMW-PAHs of various ring sizes, including 4 rings (pyrene and fluoranthene), 5 rings [benzo(a)pyrene], and 6 rings [benzo(ghi)perylene], with the highest enzymatic activity being toward the 5-ring PAH followed by the 4-ring and 6-ring PAHs, in that order. Recombinant CYP63A2 activity yielded monohydroxylated PAH metabolites. The enzyme was found to also act as an alkane ω-hydroxylase that oxidizedn-alkanes with various chain lengths (C9to C12and C15to C19), as well as alkyl side chains (C3to C9) in alkylphenols (APs). CYP63A2 showed preferential oxidation of long-chain APs and alkanes. To our knowledge, this is the first P450 identified from any of the biological kingdoms that possesses such broad substrate specificity toward structurally diverse xenobiotics (PAHs, APs, and alkanes), making it a potent enzyme biocatalyst candidate to handle mixed pollution (e.g., crude oil spills).

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Insights into carbon-nanotube-assisted electrooxidation of polycyclic aromatic hydrocarbons for mediated bioelectrocatalysis

Chemical Communications ◽

10.1039/d1cc02958d ◽

2021 ◽

Author(s):

Paulo Henrique Maciel Buzzetti ◽

Pierre-Yves Blanchard ◽

Emerson Marcelo Girotto ◽

Yuta Nishina ◽

Serge Cosnier ◽

...

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Carbon Nanotube ◽

Aromatic Hydrocarbons ◽

Polycyclic Aromatics ◽

Π Stacking ◽

Polycyclic Aromatic ◽

Mediated Bioelectrocatalysis

A series of polycyclic aromatics, naphthalene, phenanthrene, perylene, pyrene, 1-pyrenebutyric acid N-hydroxysuccinimide ester (pyrene NHS) and coronene, were immobilized via π stacking on carbon nanotube (CNT) electrodes and electro-oxidized in...

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