scholarly journals The soluble methane mono-oxygenase of Methylococcus capsulatus (Bath). Its ability to oxygenate n-alkanes, n-alkenes, ethers, and alicyclic, aromatic and heterocyclic compounds

1977 ◽  
Vol 165 (2) ◽  
pp. 395-402 ◽  
Author(s):  
J Colby ◽  
D I Stirling ◽  
H Dalton
Keyword(s):  
Aromatic Compounds ◽  
Heterocyclic Compounds ◽  
Catalytic Properties ◽  
Methylococcus Capsulatus ◽  
Methylosinus Trichosporium ◽  
Styrene Epoxide ◽  
Cyclic Alkanes ◽  
Methylomonas Albus ◽  
Terminal Oxidation ◽  
Methylomonas Methanica

1. Methane mono-oxygenase of Methylococcus capsulatus (Bath) catalyses the oxidation of various substituted methane derivatives including methanol. 2. It is a very non-specific oxygenase and, in some of its catalytic properties, apparently resembles the analogous enzyme from Methylomonas methanica but differs from those found in Methylosinus trichosporium and Methylomonas albus. 3. CO is oxidized to CO2. 4. C1-C8 n-alkanes are hydroxylated, yielding mixtures of the corresponding 1- and 2-alcohols; no 3- or 4-alcohols are formed. 5. Terminal alkenes yield the corresponding 1,2-epoxides. cis- or trans-but-2-ene are each oxidized to a mixture of 2,3-epoxybutane and but-2-en-1-ol with retention of the cis or trans configuration in both products; 2-butanone is also formed from cis-but-2-ene only. 6. Dimethyl ether is oxidized. Diethyl ether undergoes sub-terminal oxidation, yielding ethanol and ethanal in equimolar amounts. 7. Methane mono-oxygenase also hydroxylates cyclic alkanes and aromatic compounds. However, styrene yields only styrene epoxide and pyridine yields only pyridine N-oxide. 8. Of those compounds tested, only NADPH can replace NADH as electron donor.

scholarly journals A comparison of the substrate and electron-donor specificities of the methane mono-oxygenases from three strains of methane-oxidizing bacteria

1979 ◽  
Vol 177 (1) ◽  
pp. 361-364 ◽  
Author(s):  
D I Stirling ◽  
J Colby ◽  
H Dalton
Keyword(s):  
Substrate Specificity ◽  
Electron Donor ◽  
Methylococcus Capsulatus ◽  
Methylosinus Trichosporium ◽  
Broad Substrate Specificity ◽  
Methane Oxidizing Bacteria ◽  
Methylomonas Methanica

1. Methane mono-oxygenase from Methylosinus trichosporium has the same broad substrate specificity as the analogous enzyme from Methylococcus capsulatus (Bath); the enzyme from Methylomonas methanica is more specific. 2. Contrary to previous reports, NAD(P)H and not ascorbate is the required electron donor for the enzyme from Methylosinus trichosporium. 3. It is concluded that these three bacteria contain similar methane mono-oxygenases.

Ruthenium red and alcian blue effects on outer structures of methanotrophic bacteria

1988 ◽  
Vol 46 ◽  
pp. 72-73
Author(s):  
T.A. Fassel ◽  
M.J. Schaller ◽  
C.C. Remsen
Keyword(s):  
Research Effort ◽  
Ruthenium Red ◽  
Outer Cell ◽  
Methanotrophic Bacteria ◽  
En Bloc ◽  
Methylosinus Trichosporium ◽  
Wall Structures ◽  
Methylomonas Albus ◽  
Type Strains ◽  
Outer Cell Wall

Methane, a contributor to the “greenhouse effect”, is oxidized in the natural environment by methanotrophic bacteria. As part of a comprehensive research effort, we have been examining the ultrastructure of methanotrophs. These microorganisms have complex outer cell wall structures similar to those frequently found in other chemol itho- trophic bacteria. (1,2)In our work, we have focused on the “type” strains of Methylomonas albus BG8 and Methylosinus trichosporium OB3b. Between Spurr and LR White embedding resins, we found a difference 1n the preservation of an outer cup layer of BG8 external to the peripheral membranes. Cells from the same sample embedded in Spurr consistently lacked this feature (FIG. 1). This effect was overcome by an en bloc ruthenium red (RR) protocol that resulted in successful retention of the cup layer in Spurr resin (FIG. 2). For OB3b cells, the en bloc RR protocol resulted in an exterior bead feature distinguishable in thin section (FIG. 4) that previously was seen only by SEM.

ÉTARD REACTION: II. POLYCYCLIC AROMATIC AND HETEROCYCLIC COMPOUNDS

1958 ◽  
Vol 36 (6) ◽  
pp. 949-951 ◽  
Author(s):  
Owen H. Wheeler
Keyword(s):  
Aromatic Compounds ◽  
Heterocyclic Compounds ◽  
Polycyclic Aromatic Compounds ◽  
Chromyl Chloride ◽  
Polycyclic Aromatic

Polycyclic aromatic compounds can, in a number of cases, be oxidized with chromyl chloride, whereas heterocyclic compounds are unaffected.

GC-MS Analyzing of Coal Tar of Lignite Briquette from Low Temperature Pyrolysis

2014 ◽  
Vol 472 ◽  
pp. 591-595 ◽  
Author(s):  
Xin Tao Cui ◽  
Yong Fa Zhang ◽  
Dong Liu Dong ◽  
Yu Qiong Zhao
Keyword(s):  
Phenolic Compounds ◽  
Low Temperature ◽  
Brown Coal ◽  
Aromatic Compounds ◽  
Heterocyclic Compounds ◽  
Coal Tar ◽  
Aliphatic Hydrocarbon ◽  
The Other ◽  
Low Temperature Pyrolysis ◽  
Content Of Oxygen

Distillation and GC-MS were employed to analysis the coal tar of low-temperature pyrolysis of lignite briquette by contrasting with standards: the fraction below 340°C in the tar distillates of brown coal tar accounted for 83.30% and the other greater than 340°C is pitch accounted for 16.32%. 34.00% of coal tar are hydrocarbons which are mainly consisted of fat aliphatic hydrocarbon and include few alkene and cycloparaffins. The content of phenolic compounds in coal tar, mainly comes from the fraction below 210°C, is 11.68%. 16.86% of coal tar is aromatic compounds which are mainly composed of substitutive derivative of polyalkylbenzene distributing in all kinds of fractions; and a small amount of aromatic compounds which is concentrated in the fraction below 300°C. The content of oxygen-containing, nitrogen-containing and heterocyclic compounds is 4.47%, 0.57%, 2.11%, respectively.

Site-Selective Shpol'skii Spectrometry of Sulfur-, Oxygen-, and Nitrogen-Containing Aromatic Compounds in Complex Samples

1988 ◽  
Vol 42 (5) ◽  
pp. 731-740 ◽  
Author(s):  
A. E. Elsaiid ◽  
R. Walker ◽  
S. Weeks ◽  
A. P. D'Silva ◽  
V. A. Fassel
Keyword(s):  
Aromatic Compounds ◽  
Heterocyclic Compounds ◽  
Direct Determination ◽  
Emission Spectra ◽  
Complex Samples ◽  
Biological Studies ◽  
Polycyclic Aromatic ◽  
Site Selective ◽  
First Time ◽  
Derivatives Of

Laser excited Shpol'skii spectrometry (LESS) was utilized to directly determine nitrogen (N-), oxygen (O-), and sulfur (S-) heterocyclic compounds in solvent refined coal (SRC-II), petroleum crude oil, and carbon black. Characteristic quasilinear LESS excitation and emission spectra of the heterocyclic compounds are presented for the first time under site-selective conditions. Deuterated analogs of dibenzothiophene and dibenzofuran were utilized for quantitation. Site-selective fluorescence spectra of aminopyrene derivatives of polycyclic aromatic compounds (PAC) are also presented for the first time. The potential for utilizing the LESS technique in critical environment and biological studies for the direct determination of N-, O-, and S-heterocyclic compounds and substitutional derivatives of parent PAC has been demonstrated.

scholarly journals Effects of pyrolysis parameters on the distribution of pyrolysis products of Miscanthus

2021 ◽  
Vol 46 ◽  
pp. 146867832110109
Author(s):  
Zhangmao Hu ◽  
Tong Zhou ◽  
Hong Tian ◽  
Leihua Feng ◽  
Can Yao ◽  
...  
Keyword(s):  
Heating Rate ◽  
Residence Time ◽  
Aromatic Compounds ◽  
Heterocyclic Compounds ◽  
Value Added ◽  
Building Blocks ◽  
Area Ratio ◽  
Relative Peak Area ◽  
Pyrolysis Products ◽  
Peak Area Ratio

This work presents a comprehensive study on the effects of pyrolysis parameters (pyrolysis temperature, residence time, and heating rate) on the distribution of pyrolysis products of Miscanthus. Py-GC/MS (Pyrolysis-gas chromatography/mass) was conducted to identify building blocks of value-added chemical from Miscanthus. The results showed that the main pyrolysis products of Miscanthus were ketone, aldehyde, phenol, heterocycles, and aromatic compounds. The representative compounds of ketone and aldehyde compounds produced at different pyrolysis temperatures changed obviously, while the representative compounds of phenolic, heterocyclic, and aromatic compounds had no obvious change. Large-scale pyrolysis of Miscanthus had begun at 400°C, and the relative content of pyrolysis products from Miscanthus reached the maximum of 98.34% at 700°C. The relative peak area ratio of phenol and aromatic compounds reached the maximum and minimum at the residence time of 5 and 10 s, while the relative peak area ratio of ketone compounds showed the opposite trend. The relative peak area ratio of aldehyde compounds was higher under shorter or longer residence time. For heterocyclic compounds, the relative peak area ratio reached the maximum of 27.0% at residence time of 10 s. The faster or slower heating rate was beneficial to the production of aldehyde and phenol compounds. The relative peak area ratio of ketone compounds reached the maximum at 10,000°C/s, 70°C/s, and 10°C/s, and the relative peak area ratio tendency of heterocyclic compounds was similar to ketone. For aromatic compounds, the overall fluctuations were large, and the relative peak area ratio was the highest at the heating rate of 100°C/s.

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