Improved performance of Pseudomonas aeruginosa catalyzed MFCs with graphite/polyester composite electrodes doped with metal ions for azo dye degradation

The functional properties of the recombinant C-terminal dimerization domain of the Pseudomonas aeruginosa Fur (ferric uptake regulator) protein expressed in and purified from Escherichia coli have been evaluated. Sedimentation velocity measurements demonstrate that this domain is dimeric, and the UV CD spectrum is consistent with a secondary structure similar to that observed for the corresponding region of the crystallographically characterized wild-type protein. The thermal stability of the domain as determined by CD spectroscopy decreases significantly as pH is increased and increases significantly as metal ions are added. Potentiometric titrations (pH 6.5) establish that the domain possesses a high-affinity and a low-affinity binding site for metal ions. The high-affinity (sensory) binding site demonstrates association constants (KA) of 10(±7)×106, 5.7(±3)×106, 2.0(±2)×106 and 2.0(±3)×104 M−1 for Ni2+, Zn2+, Co2+ and Mn2+ respectively, while the low-affinity (structural) site exhibits association constants of 1.3(±2)×106, 3.2(±2)×104, 1.76(±1)×105 and 1.5(±2)×103 M−1 respectively for the same metal ions (pH 6.5, 300 mM NaCl, 25 °C). The stability of metal ion binding to the sensory site follows the Irving–Williams order, while metal ion binding to the partial sensory site present in the domain does not. Fluorescence experiments indicate that the quenching resulting from binding of Co2+ is reversed by subsequent titration with Zn2+. We conclude that the domain is a reasonable model for many properties of the full-length protein and is amenable to some analyses that the limited solubility of the full-length protein prevents.

Download Full-text

Electrokinetic Remediation of Heavy Metal Contaminated Soil Using Permeable Reactive Composite Electrodes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.361 ◽

2012 ◽

Vol 518-523 ◽

pp. 361-368 ◽

Cited By ~ 3

Author(s):

Rong Bing Fu ◽

Xin Xing Liu ◽

Fang Liu ◽

Jin Ma ◽

Yu Mei Ma ◽

...

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Removal Efficiency ◽

Heavy Metal Ions ◽

Metal Removal ◽

Heavy Metal Removal ◽

Ph Control ◽

Electrokinetic Remediation ◽

Composite Electrodes ◽

Remediation Process

A new permeable reactive composite electrode (PRCE) attached with a permeable reactive layer (PRL) of Fe0 and zeolite has been developed for soil pH control and the improved removal efficiency of heavy metal ions (Cd, Ni, Pb, Cu) from soil in electrokinetic remediation process. The effects of different composite electrodes on pH control and heavy metal removal efficiency were studied, and changes in the forms of heavy metals moved onto the electrodes were analyzed. The results showed that with acidic/alkaline zeolite added and renewed in time, the composite electrodes could effectively neutralize and capture H+ and OH- produced from electrolysis of the anolyte and catholyte, avoiding or delaying the formation of acidic/alkaline front in tested soil, preventing premature precipitation of heavy metal ions and over-acidification of soil, and thus significantly improved the heavy metal removal efficiency. Fe0 in composite electrodes could deoxidize and stabilize the heavy metal ions. After that capture and immobilization of the pollutants were achieved. The results also showed that, using "Fe0 + zeolite" PRCE in the cathode with timely renewal, after 15-day remediation with a DC voltage of 1.5 V/cm, the total removal rates of Cd, Pb, Cu and Ni were 49.4%, 47.1%, 36.7% and 39.2%, respectively.

Download Full-text

Degradation of an Azo Dye by Fenton Type Processes Assisted with UV Irradiation

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1462 ◽

2007 ◽

Vol 5 (1) ◽

Cited By ~ 3

Author(s):

Natalija Koprivanac ◽

Dinko Vujevic

Keyword(s):

Uv Irradiation ◽

Azo Dye ◽

Dye Degradation ◽

Degradation Products ◽

Batch Reactor ◽

Process Efficiency ◽

Molar Ratio ◽

Synthetic Dyes ◽

Ambient Conditions ◽

Treatment Methods

Organic synthetic dyes are widely produced and used today. Significant losses of organic and inorganic content occurs during the manufacturing and application of dyes and its discharge in the effluent presents a threat to the eco-systems due to general toxicity and resistance to destruction by biological treatment methods. Particularly azo dyes are of special environmental concern due to their degradation products such as aromatic amines, which are considered highly carcinogenic. So, dyes have to be removed from coloured wastewater before discharge. However, traditional treatment methods (adsorption, coagulation/flocculation) mainly transfer the contaminants from wastewater to secondary waste. Therefore, advanced oxidation processes seem to be sustainable and clean technology to decolorize and minimize organic dyes content from wastewater. In this paper, degradation of an azo dye C.I. Direct Orange 39 (DO39) using Fenton type processes (Fe2+/H2O2, Fe3+/H2O2and Fe0/H2O2) has been performed. The molar ratio of Fentons type reagents has been varied in the range of 1 : 5 up to 1 : 50 at 0.5 and 1.0 mM concentrations of iron salts and iron powder. Experiments have been conducted for two hours in a batch reactor with magnetic stirring, ambient conditions and pH 3. The process efficiency and formation of degradation by-products have been determined on the basis of results obtained by UV/VIS spectrophotometric, total organic carbon (TOC) and high performance liquid chromatography (HPLC) analyses. The optimal Fenton and Fenton ``like" processes parameters have been applied in the photo reactor, too. It has been observed that simultaneous utilization of UV irradiation with Fenton's and Fenton ``like" reagents increases the degradation of DO39 dye. Degradation of the dye in dilute aqueous solution follows pseudo-first order kinetics. The maximal decolourization of 20 mg L-1 DO39 in water of 93.2% and TOC degradation of 76.9% were obtained using Fe3+/H2O2= 1 : 5 molar ratio. The results indicate that the treatment of DO39 dye wastewater with UV/Fe3 +/H2O2 system was found to be the most efficient.

Download Full-text

Azo dye degradation by Phanerochaete chrysosporium in the medium enriched with nitrogen in the presence of primary co-substrate

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132013000500019 ◽

2013 ◽

Vol 56 (5) ◽

pp. 867-874 ◽

Cited By ~ 5

Author(s):

Marcus Vinicius Freire Andrade ◽

Karla Mayara Lima da Silva ◽

João Paulo da Silva Siqueira ◽

Carlos Ronald Pessoa Wanderley ◽

Rinaldo dos Santos Araújo ◽

...

Keyword(s):

Phanerochaete Chrysosporium ◽

Azo Dye ◽

Dye Degradation

Download Full-text

Fe-based metallic glass catalyst with nanoporous surface for azo dye degradation

Chemosphere ◽

10.1016/j.chemosphere.2017.01.094 ◽

2017 ◽

Vol 174 ◽

pp. 76-81 ◽

Cited By ~ 29

Author(s):

Z. Deng ◽

X.H. Zhang ◽

K.C. Chan ◽

L. Liu ◽

T. Li

Keyword(s):

Metallic Glass ◽

Azo Dye ◽

Dye Degradation ◽

Nanoporous Surface

Download Full-text

Studies on decolorisation of textile azo dye, mordant black 17 using Pseudomonas aeruginosa SBU7, isolated from textile effluent

International Conference on Green technology and environmental Conservation (GTEC-2011) ◽

10.1109/gtec.2011.6167676 ◽

2011 ◽

Author(s):

Karunya. A ◽

C.Valli Nachiyar ◽

C. Rose

Keyword(s):

Pseudomonas Aeruginosa ◽

Azo Dye ◽

Textile Effluent

Download Full-text

Studies on the biofilm produced by Pseudomonas aeruginosa grown in different metal fatty acid salt media and its application in biodegradation of fatty acids and bioremediation of heavy metal ions

Canadian Journal of Microbiology ◽

10.1139/cjm-2015-0384 ◽

2017 ◽

Vol 63 (1) ◽

pp. 61-73 ◽

Cited By ~ 5

Author(s):

P. Abinaya Sindu ◽

Pennathur Gautam

Keyword(s):

Pseudomonas Aeruginosa ◽

Fatty Acid ◽

Metal Ions ◽

Metal Ion ◽

High Performance ◽

Toxic Metal ◽

Industrial Effluents ◽

Aquatic Organism ◽

Fatty Acid Salt ◽

Planktonic Form

Metal fatty acid salts (MFAS) in untreated industrial effluents cause environmental pollution. The use of biocompatible agents for remediation may help in reducing the harm caused to the ambient aquatic organism. Pseudomonas aeruginosa is a ubiquitous organism that thrives under harsh conditions and is resistant to toxic metal ions. The present study shows a proof-of-concept of using this organism in the biodegradation of MFAS. MFAS were prepared and we studied their effect on the growth of the planktonic form and the formation of biofilm by P. aeruginosa. We observed biofilm formation in the presence of all the MFAS when used as the sole carbon source, albeit the quantity of biofilm formed in the presence of cadmium and copper was less. There was no effect on the planktonic form of the organism but the formation of biofilm increased in the presence of magnesium palmitate. This study shows that metal ions play a pivotal role in the formation of biofilm. HPLC (high-performance liquid chromatography) analysis of the biofilm polysaccharide showed that hexose sugar was a major component when compared with pentose sugar. The structure of biofilm polysaccharide and the coordination of the metal ion with the biofilm polysaccharide were confirmed by FTIR (Fourier transform infrared spectroscopy) and Raman spectroscopy.

Download Full-text