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

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.

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.

scholarly journals Degradation of Diphenyl Ether in Sphingobium phenoxybenzoativorans SC_3 Is Initiated by a Novel Ring Cleavage Dioxygenase

2017 ◽  
Vol 83 (10) ◽  
Author(s):  
Shu Cai ◽  
Li-Wei Chen ◽  
Yu-Chun Ai ◽  
Ji-Guo Qiu ◽  
Cheng-Hong Wang ◽  
...  
Keyword(s):  
Benzene Ring ◽  
Aromatic Compounds ◽  
Diphenyl Ether ◽  
Angular Position ◽  
Heme Iron ◽  
Ring Cleavage ◽  
Phenyl Ester ◽  
Muconic Acid ◽  
Content Type ◽  
Angular Dioxygenase

ABSTRACT Sphingobium phenoxybenzoativorans SC_3 degrades and utilizes diphenyl ether (DE) or 2-carboxy-DE as its sole carbon and energy source. In this study, we report the degradation of DE and 2-carboxy-DE initiated by a novel ring cleavage angular dioxygenase (diphenyl ether dioxygenase [Dpe]) in the strain. Dpe functions at the angular carbon and its adjacent carbon (C-1a, C-2) of a benzene ring in DE (or the 2-carboxybenzene ring in 2-carboxy-DE) and cleaves the C-1a—C-2 bond (decarboxylation occurs simultaneously for 2-carboxy-DE), yielding 2,4-hexadienal phenyl ester, which is subsequently hydrolyzed to muconic acid semialdehyde and phenol. Dpe is a type IV Rieske non-heme iron oxygenase (RHO) and consists of three components: a hetero-oligomer oxygenase, a [2Fe-2S]-type ferredoxin, and a glutathione reductase (GR)-type reductase. Genetic analyses revealed that dpeA1A2 plays an essential role in the degradation and utilization of DE and 2-carboxy-DE in S. phenoxybenzoativorans SC_3. Enzymatic study showed that transformation of 1 molecule of DE needs two molecules of oxygen and two molecules of NADH, supporting the assumption that the cleavage of DE catalyzed by Dpe is a continuous two-step dioxygenation process: DE is dioxygenated at C-1a and C-2 to form a hemiacetal-like intermediate, which is further deoxygenated, resulting in the cleavage of the C-1a—C-2 bond to form one molecule of 2,4-hexadienal phenyl ester and two molecules of H2O. This study extends our knowledge of the mode and mechanism of ring cleavage of aromatic compounds. IMPORTANCE Benzene ring cleavage, catalyzed by dioxygenase, is the key and speed-limiting step in the aerobic degradation of aromatic compounds. As previously reported, in the ring cleavage of DEs, the benzene ring needs to be first dihydroxylated at a lateral position and subsequently dehydrogenated and opened through extradiol cleavage. This process requires three enzymes (two dioxygenases and one dehydrogenase). In this study, we identified a novel angular dioxygenase (Dpe) in S. phenoxybenzoativorans SC_3. Under Dpe-mediated catalysis, the benzene ring of DE is dioxygenated at the angular position (C-1a, C-2), resulting in the cleavage of the C-1a—C-2 bond to generate a novel product, 2,4-hexadienal phenyl ester. This process needs only one angular dioxygenase, Dpe. Thus, the ring cleavage catalyzed by Dpe represents a novel mechanism of benzene ring cleavage.

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 Identification and Characterization of Genes Involved in the Downstream Degradation Pathway of γ-Hexachlorocyclohexane in Sphingomonas paucimobilis UT26

2005 ◽  
Vol 187 (3) ◽  
pp. 847-853 ◽  
Author(s):  
Ryo Endo ◽  
Mayuko Kamakura ◽  
Keisuke Miyauchi ◽  
Masao Fukuda ◽  
Yoshiyuki Ohtsubo ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Gene Clusters ◽  
Sole Source ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Sphingomonas Paucimobilis ◽  
Reductase Gene ◽  
Chlorinated Aromatic Compounds ◽  
Identification And Characterization

ABSTRACT Sphingomonas paucimobilis UT26 utilizes γ-hexachlorocyclohexane (γ-HCH) as a sole source of carbon and energy. In our previous study, we cloned and characterized genes that are involved in the conversion of γ-HCH to maleylacetate (MA) via chlorohydroquinone (CHQ) in UT26. In this study, we identified and characterized an MA reductase gene, designated linF, that is essential for the utilization of γ-HCH in UT26. A gene named linEb, whose deduced product showed significant identity to LinE (53%), was located close to linF. LinE is a novel type of ring cleavage dioxygenase that catalyzes the conversion of CHQ to MA. LinEb expressed in Escherichia coli transformed CHQ and 2,6-dichlorohydroquinone to MA and 2-chloromaleylacetate, respectively. Our previous and present results indicate that UT26 (i) has two gene clusters for degradation of chlorinated aromatic compounds via hydroquinone-type intermediates and (ii) uses at least parts of both clusters for γ-HCH utilization.

scholarly journals Transcriptomic Analysis Reveals a Bifurcated Terephthalate Degradation Pathway in Rhodococcus sp. Strain RHA1

2006 ◽  
Vol 189 (5) ◽  
pp. 1641-1647 ◽  
Author(s):  
Hirofumi Hara ◽  
Lindsay D. Eltis ◽  
Julian E. Davies ◽  
William W. Mohn
Keyword(s):  
Aromatic Compounds ◽  
Degradation Pathway ◽  
Transcriptomic Analysis ◽  
Ring Cleavage ◽  
Wide Range ◽  
Genes Encoding ◽  
Catechol 1,2 Dioxygenase ◽  
Rhodococcus Sp ◽  
Dioxygenase Activity ◽  
In Cells

ABSTRACT Phthalate isomers and their esters are important pollutants whose biodegradation is not well understood. Rhodococcus sp. strain RHA1 is notable for its ability to degrade a wide range of aromatic compounds. RHA1 was previously shown to degrade phthalate (PTH) and to have genes putatively encoding terephthalate (TPA) degradation. Transcriptomic analysis of 8,213 genes indicated that 150 were up-regulated during growth on PTH and that 521 were up-regulated during growth on TPA. Distinct ring cleavage dioxygenase systems were differentially expressed during growth on PTH and TPA. Genes encoding the protocatechuate (PCA) pathway were induced on both substrates, while genes encoding the catechol branch of the PCA pathway were additionally induced only on TPA. Accordingly, protocatechuate-3,4-dioxygenase activity was induced in cells grown on both substrates, while catechol-1,2-dioxygenase activity was induced only in cells grown on TPA. Knockout analysis indicated that pcaL, encoding 3-oxoadipate enol-lactone hydrolase and 4-carboxymuconolactone decarboxylase, was required for growth on both substrates but that pcaB, encoding β-carboxy-cis,cis-muconate lactonizing enzyme, was required for growth on PTH only. These results indicate that PTH is degraded solely via the PCA pathway, whereas TPA is degraded via a bifurcated pathway that additionally includes the catechol branch of the PCA pathway.

scholarly journals A genomic analysis of the catabolism of aromatic compounds in Azospirillum brasilense SR80

2020 ◽  
Author(s):  
Ye. V. Kryuchkova ◽  
G. L. Burygin ◽  
N. E. Gogoleva ◽  
Y. V. Gogolev ◽  
E. I. Shagimardanova ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Aromatic Compounds ◽  
Azospirillum Brasilense ◽  
Genomic Analysis ◽  
Ring Cleavage

We performed a genomic analysis of the presence and organization of oxygenases involved in the hydroxylation of various substrates, including the aromatic ring, and dioxygenases catalyzing a ring-cleavage of the formed hydroxylated intermediates in A. brasilense SR80.

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