scholarly journals Effect of carbon starvation on toluene degradation activity by toluene monooxygenase-expressing bacteria

2006 ◽  
Vol 17 (5) ◽  
pp. 437-445 ◽  
Author(s):  
David R. Johnson ◽  
Joonhong Park ◽  
Jerome J. Kukor ◽  
Linda M. Abriola
Keyword(s):  
Carbon Starvation ◽  
Toluene Degradation ◽  
Toluene Monooxygenase ◽  
Degradation Activity

scholarly journals Efficient Photocatalytic Degradation of Gaseous Benzene and Toluene over Novel Hybrid PIL@TiO2/m-GO Composites

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 126 ◽  
Author(s):  
Shayeste Shajari ◽  
Elaheh Kowsari ◽  
Naemeh Seifvand ◽  
Farshad Boorboor Ajdari ◽  
Amutha Chinnappan ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Toluene Degradation ◽  
Pollutant Degradation ◽  
Polymerized Ionic Liquid ◽  
Photodegradation Rate ◽  
Microstructural Morphology ◽  
Degradation Activity ◽  
Poly Ionic Liquid ◽  
Optimized Conditions ◽  
Gaseous Benzene

In this work, the PIL (poly ionic liquid)@TiO2 composite was designed with two polymerized ionic liquid concentrations (low and high) and evaluated for pollutant degradation activity for benzene and toluene. The results showed that PIL (low)@TiO2 composite was more active than PIL (high)@TiO2 composites. The photodegradation rate of benzene and toluene pollutants by PIL (low)@TiO2 and PIL (high)@TiO2 composites was obtained as 86% and 74%, and 59% and 46%, respectively, under optimized conditions. The bandgap of TiO2 was markedly lowered (3.2 eV to 2.2 eV) due to the formation of PIL (low)@TiO2 composite. Besides, graphene oxide (GO) was used to grow the nano-photocatalysts’ specific surface area. The as-synthesized PIL (low)@TiO2@GO composite showed higher efficiency for benzene and toluene degradation which corresponds to 91% and 83%, respectively. The resultant novel hybrid photocatalyst (PIL@TiO2/m-GO) was prepared and appropriately characterized for their microstructural, morphology, and catalytic properties. Among the studied photocatalysts, the PIL (low)@TiO2@m-GO composite exhibits the highest activity in the degradation of benzene (97%) and toluene (97%). The ultimate bandgap of the composite reached 2.1 eV. Our results showed that the as-prepared composites hold an essential role for future considerations over organic pollutants.

Induction kinetics of aerobic toluene degradation as a function of carbon starvation history

2008 ◽  
Vol 43 (12) ◽  
pp. 1345-1351 ◽  
Author(s):  
Joonhong Park ◽  
John Lang ◽  
Kaliannan Thamaraiselvi ◽  
Jerome J. Kukor ◽  
Linda M. Abriola
Keyword(s):  
Carbon Starvation ◽  
Toluene Degradation ◽  
Induction Kinetics ◽  
Kinetics Of

scholarly journals Effects of Iron Limitation on the Degradation of Toluene by Pseudomonas Strains Carrying the TOL (pWWO) Plasmid

2001 ◽  
Vol 67 (8) ◽  
pp. 3406-3412 ◽  
Author(s):  
Inez J. T. Dinkla ◽  
Esther M. Gabor ◽  
Dick B. Janssen
Keyword(s):  
Iron Limitation ◽  
Aerobic Biodegradation ◽  
Iron Availability ◽  
Toluene Degradation ◽  
Tol Plasmid ◽  
Toluene Monooxygenase ◽  
Rhizosphere Bacterium ◽  
Oxidative Breakdown ◽  
Iron Requirement ◽  
Substrate Affinities

ABSTRACT Most aerobic biodegradation pathways for hydrocarbons involve iron-containing oxygenases. In iron-limited environments, such as the rhizosphere, this may influence the rate of degradation of hydrocarbon pollutants. We investigated the effects of iron limitation on the degradation of toluene by Pseudomonas putida mt2 and the transconjugant rhizosphere bacterium P. putidaWCS358(pWWO), both of which contain the pWWO (TOL) plasmid that harbors the genes for toluene degradation. The results of continuous-culture experiments showed that the activity of the upper-pathway toluene monooxygenase decreased but that the activity of benzyl alcohol dehydrogenase was not affected under iron-limited conditions. In contrast, the activities of three meta-pathway (lower-pathway) enzymes were all found to be reduced when iron concentrations were decreased. Additional experiments in which citrate was used as a growth substrate and the pathways were induced with the gratuitous inducer o-xylene showed that expression of the TOL genes increased the iron requirement in both strains. Growth yields were reduced and substrate affinities decreased under iron-limited conditions, suggesting that iron availability can be an important parameter in the oxidative breakdown of hydrocarbons.

scholarly journals Tuning flavin environment to detect and control light-induced conformational switching in Drosophila cryptochrome

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Siddarth Chandrasekaran ◽  
Connor M. Schneps ◽  
Robert Dunleavy ◽  
Changfan Lin ◽  
Cristina C. DeOliveira ◽  
...  
Keyword(s):  
Side Reactions ◽  
Resonance Spectroscopy ◽  
Conformational Switching ◽  
Spin Resonance ◽  
Degradation Activity ◽  
Recognition Motifs ◽  
Cellular Turnover ◽  
Control Light ◽  
Dynamics Simulations ◽  
And Control

AbstractLight-induction of an anionic semiquinone (SQ) flavin radical in Drosophila cryptochrome (dCRY) alters the dCRY conformation to promote binding and degradation of the circadian clock protein Timeless (TIM). Specific peptide ligation with sortase A attaches a nitroxide spin-probe to the dCRY C-terminal tail (CTT) while avoiding deleterious side reactions. Pulse dipolar electron-spin resonance spectroscopy from the CTT nitroxide to the SQ shows that flavin photoreduction shifts the CTT ~1 nm and increases its motion, without causing full displacement from the protein. dCRY engineered to form the neutral SQ serves as a dark-state proxy to reveal that the CTT remains docked when the flavin ring is reduced but uncharged. Substitutions of flavin-proximal His378 promote CTT undocking in the dark or diminish undocking in the light, consistent with molecular dynamics simulations and TIM degradation activity. The His378 variants inform on recognition motifs for dCRY cellular turnover and strategies for developing optogenetic tools.

Toluene degradation by heterogeneous photocatalysis assisted with ozone in a tubular reactor: analysis over the reactor length

2021 ◽  
Author(s):  
Bárbara Maria Borges Ribeiro ◽  
Renato Carajelescov Nonato ◽  
Tânia Miyoko Fujimoto ◽  
Bianca Gvozdenovic Medina Bricio ◽  
Ursula Luana Rochetto Doubek ◽  
...  
Keyword(s):  
Tubular Reactor ◽  
Heterogeneous Photocatalysis ◽  
Toluene Degradation ◽  
Reactor Length
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