scholarly journals Reactions Involved in the Lower Pathway for Degradation of 4-Nitrotoluene by Mycobacterium Strain HL 4-NT-1

2000 ◽  
Vol 66 (7) ◽  
pp. 3010-3015 ◽  
Author(s):  
Zhongqi He ◽  
Jim C. Spain
Keyword(s):  
Aromatic Compounds ◽  
Nitroaromatic Compounds ◽  
Aerobic Biodegradation ◽  
Ring Cleavage ◽  
Pseudomonas Pseudoalcaligenes ◽  
Substrate Specificities ◽  
Number Of Microorganisms

ABSTRACT In spite of the variety of initial reactions, the aerobic biodegradation of aromatic compounds generally yields dihydroxy intermediates for ring cleavage. Recent investigation of the degradation of nitroaromatic compounds revealed that some nitroaromatic compounds are initially converted to 2-aminophenol rather than dihydroxy intermediates by a number of microorganisms. The complete pathway for the metabolism of 2-aminophenol during the degradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 has been elucidated previously. The pathway is parallel to the catechol extradiol ring cleavage pathway, except that 2-aminophenol is the ring cleavage substrate. Here we report the elucidation of the pathway of 2-amino-4-methylphenol (6-amino-m-cresol) metabolism during the degradation of 4-nitrotoluene by Mycobacterium strain HL 4-NT-1 and the comparison of the substrate specificities of the relevant enzymes in strains JS45 and HL 4-NT-1. The results indicate that the 2-aminophenol ring cleavage pathway in strain JS45 is not unique but is representative of the pathways of metabolism of othero-aminophenolic compounds.

scholarly journals Ring-Cleavage Products Produced during the Initial Phase of Oxidative Treatment of Alkyl-Substituted Aromatic Compounds

2020 ◽  
Vol 54 (13) ◽  
pp. 8352-8361 ◽  
Author(s):  
Jean Van Buren ◽  
Carsten Prasse ◽  
Emily L. Marron ◽  
Brighton Skeel ◽  
David L. Sedlak
Keyword(s):  
Aromatic Compounds ◽  
Initial Phase ◽  
Ring Cleavage ◽  
Oxidative Treatment

Hydrogen Bond-Accelerated meta-Selective C–H Borylation of Aromatic Compounds and Expression of Functional Group and Substrate Specificities

ACS Catalysis ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 1705-1709 ◽  
Author(s):  
Xu Lu ◽  
Yusuke Yoshigoe ◽  
Haruka Ida ◽  
Mitsumi Nishi ◽  
Motomu Kanai ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Aromatic Compounds ◽  
Functional Group ◽  
Substrate Specificities

scholarly journals Epoxy Coenzyme A Thioester Pathways for Degradation of Aromatic Compounds

2012 ◽  
Vol 78 (15) ◽  
pp. 5043-5051 ◽  
Author(s):  
Wael Ismail ◽  
Johannes Gescher
Keyword(s):  
Aromatic Ring ◽  
Aromatic Compounds ◽  
Coenzyme A ◽  
Environmental Pollutants ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
The Novel ◽  
Energy Consuming ◽  
Coa Thioesters ◽  
Hydrolytic Mechanism

ABSTRACTAromatic compounds (biogenic and anthropogenic) are abundant in the biosphere. Some of them are well-known environmental pollutants. Although the aromatic nucleus is relatively recalcitrant, microorganisms have developed various catabolic routes that enable complete biodegradation of aromatic compounds. The adopted degradation pathways depend on the availability of oxygen. Under oxic conditions, microorganisms utilize oxygen as a cosubstrate to activate and cleave the aromatic ring. In contrast, under anoxic conditions, the aromatic compounds are transformed to coenzyme A (CoA) thioesters followed by energy-consuming reduction of the ring. Eventually, the dearomatized ring is opened via a hydrolytic mechanism. Recently, novel catabolic pathways for the aerobic degradation of aromatic compounds were elucidated that differ significantly from the established catabolic routes. The new pathways were investigated in detail for the aerobic bacterial degradation of benzoate and phenylacetate. In both cases, the pathway is initiated by transforming the substrate to a CoA thioester and all the intermediates are bound by CoA. The subsequent reactions involve epoxidation of the aromatic ring followed by hydrolytic ring cleavage. Here we discuss the novel pathways, with a particular focus on their unique features and occurrence as well as ecological significance.

scholarly journals Key Aromatic-Ring-Cleaving Enzyme, Protocatechuate 3,4-Dioxygenase, in the Ecologically Important MarineRoseobacter Lineage

2000 ◽  
Vol 66 (11) ◽  
pp. 4662-4672 ◽  
Author(s):  
Alison Buchan ◽  
Lauren S. Collier ◽  
Ellen L. Neidle ◽  
Mary Ann Moran
Keyword(s):  
Aromatic Compounds ◽  
Southern Hybridization ◽  
Ring Cleavage ◽  
Degenerate Pcr ◽  
Cell Extracts ◽  
Aromatic Compound Degradation ◽  
Genes Encoding ◽  
Cleavage Enzyme ◽  
Key Enzyme ◽  
Dioxygenase Activity

ABSTRACT Aromatic compound degradation in six bacteria representing an ecologically important marine taxon of the α-proteobacteria was investigated. Initial screens suggested that isolates in theRoseobacter lineage can degrade aromatic compounds via the β-ketoadipate pathway, a catabolic route that has been well characterized in soil microbes. Six Roseobacter isolates were screened for the presence of protocatechuate 3,4-dioxygenase, a key enzyme in the β-ketoadipate pathway. All six isolates were capable of growth on at least three of the eight aromatic monomers presented (anthranilate, benzoate, p-hydroxybenzoate, salicylate, vanillate, ferulate, protocatechuate, and coumarate). Four of the Roseobacter group isolates had inducible protocatechuate 3,4-dioxygenase activity in cell extracts when grown onp-hydroxybenzoate. The pcaGH genes encoding this ring cleavage enzyme were cloned and sequenced from two isolates,Sagittula stellata E-37 and isolate Y3F, and in both cases the genes could be expressed in Escherichia coli to yield dioxygenase activity. Additional genes involved in the protocatechuate branch of the β-ketoadipate pathway (pcaC,pcaQ, and pobA) were found to cluster withpcaGH in these two isolates. Pairwise sequence analysis of the pca genes revealed greater similarity between the twoRoseobacter group isolates than between genes from eitherRoseobacter strain and soil bacteria. A degenerate PCR primer set targeting a conserved region within PcaH successfully amplified a fragment of pcaH from two additionalRoseobacter group isolates, and Southern hybridization indicated the presence of pcaH in the remaining two isolates. This evidence of protocatechuate 3,4-dioxygenase and the β-ketoadipate pathway was found in all six Roseobacterisolates, suggesting widespread abilities to degrade aromatic compounds in this marine lineage.

The degradation of p-toluenesulfonate by a Pseudomonas

1970 ◽  
Vol 16 (5) ◽  
pp. 309-316 ◽  
Author(s):  
D. D. Focht ◽  
F. D. Williams
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Aromatic Compounds ◽  
Carbon Sources ◽  
Sole Source ◽  
Carbon Chain ◽  
Ring Cleavage ◽  
Resting Cells ◽  
Resting Cell ◽  
Complete Mineralization

A Pseudomonas isolated from sewage was adapted to use p-toluenesulfonate as the sole source of both carbon and sulfur. Very few of over 30 aromatic compounds tested were used for growth as sole carbon sources. Significantly, sulfobenzoate, phenolsulfonates, and isomers of cresolsulfonates did not support growth. Respirometry studies with washed, resting cells showed similar results. In both studies, benzenesulfonate was always used more rapidly than p-toluenesulfonate. The degradation of p-toluenesulfonate was shown to be over 90% of the theoretical value required for complete mineralization to carbon dioxide, water, and sulfate. When resting cells were incubated with 35S-p-toluenesulfonate, the ratio of oxygen uptake to 35S-sulfate liberation remained constant during the complete degradation period. Radiochromatographic analysis showed no 35S-aromatic intermediates in resting-cell supernatants at any time. Resting cells previously incubated with 35S-p-toluenesulfonate liberated two 35S-labeled aromatic intermediates upon disruption. Resting cells incubated with 1-14C-p-toluenesulfonate produced labeled 3-methylcatechol, labeled acetate, and unlabeled pyruvate. The labeled intermediate, 3-methylcatechol, was degraded by cell-free extracts to labeled acetate. Hydroxylation, desulfonation, ring cleavage, and subsequent fissions of the carbon chain occurred in that order; all steps but the first were catalyzed by cell-free extracts.

A novel method to supply the inhibitory aromatic compounds in aerobic biodegradation process

1992 ◽  
Vol 6 (6) ◽  
pp. 489-494 ◽  
Author(s):  
Yong-Bok Choi ◽  
Jang-Young Lee ◽  
Hye-Kyung Lim ◽  
Hak-Sung Kim
Keyword(s):  
Aromatic Compounds ◽  
Aerobic Biodegradation ◽  
Biodegradation Process ◽  
Novel Method

scholarly journals Determination of Key Metabolites during Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine with Rhodococcus sp. Strain DN22

2002 ◽  
Vol 68 (1) ◽  
pp. 166-172 ◽  
Author(s):  
Diane Fournier ◽  
Annamaria Halasz ◽  
Jim Spain ◽  
Petr Fiurasek ◽  
Jalal Hawari
Keyword(s):  
Molecular Mass ◽  
Degradation Products ◽  
Degradation Pathway ◽  
Aerobic Biodegradation ◽  
Ring Cleavage ◽  
Molecular Formula ◽  
Dead End ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

ABSTRACT Rhodococcus sp. strain DN22 can convert hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to nitrite, but information on degradation products or the fate of carbon is not known. The present study describes aerobic biodegradation of RDX (175 μM) when used as an N source for strain DN22. RDX was converted to nitrite (NO2 −) (30%), nitrous oxide (N2O) (3.2%), ammonia (10%), and formaldehyde (HCHO) (27%), which later converted to carbon dioxide. In experiments with ring-labeled [15N]-RDX, gas chromatographic/mass spectrophotometric (GC/MS) analysis revealed N2O with two molecular mass ions: one at 44 Da, corresponding to 14N14NO, and the second at 45 Da, corresponding to 15N14NO. The nonlabeled N2O could be formed only from -NO2, whereas the 15N-labeled one was presumed to originate from a nitramine group (15N-14NO2) in RDX. Liquid chromatographic (LC)-MS electrospray analyses indicated the formation of a dead end product with a deprotonated molecular mass ion [M-H] at 118 Da. High-resolution MS indicated a molecular formula of C2H5N3O3. When the experiment was repeated with ring-labeled [15N]-RDX, the [M-H] appeared at 120 Da, indicating that two of the three N atoms in the metabolite originated from the ring in RDX. When [U-14C]-RDX was used in the experiment, 64% of the original radioactivity in RDX incorporated into the metabolite with a molecular weight (MW) of 119 (high-pressure LC/radioactivity) and 30% in 14CO2 (mineralization) after 4 days of incubation, suggesting that one of the carbon atoms in RDX was converted to CO2 and the other two were incorporated in the ring cleavage product with an MW of 119. Based on the above stoichiometry, we propose a degradation pathway for RDX based on initial denitration followed by ring cleavage to formaldehyde and the dead end product with an MW of 119.

scholarly journals Advances in engineering microbial biosynthesis of aromatic compounds and related compounds

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Roman M. Dickey ◽  
Amanda M. Forti ◽  
Aditya M. Kunjapur
Keyword(s):  
Amino Acids ◽  
Aromatic Compounds ◽  
Review Article ◽  
Ring Cleavage ◽  
Future Research ◽  
Aromatic Polymer ◽  
Recent Trends ◽  
Considerable Work ◽  
Microbial Biosynthesis ◽  
Related Compounds

AbstractAromatic compounds have broad applications and have been the target of biosynthetic processes for several decades. New biomolecular engineering strategies have been applied to improve production of aromatic compounds in recent years, some of which are expected to set the stage for the next wave of innovations. Here, we will briefly complement existing reviews on microbial production of aromatic compounds by focusing on a few recent trends where considerable work has been performed in the last 5 years. The trends we highlight are pathway modularization and compartmentalization, microbial co-culturing, non-traditional host engineering, aromatic polymer feedstock utilization, engineered ring cleavage, aldehyde stabilization, and biosynthesis of non-standard amino acids. Throughout this review article, we will also touch on unmet opportunities that future research could address.

Sign in / Sign up

Export Citation Format

Share Document