Role of quinones in the biodegradation of priority pollutants: a review

2000 ◽  
Vol 42 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
J.A. Field ◽  
F.J. Cervantes ◽  
F.P. van der Zee ◽  
G. Lettinga
Keyword(s):  
Humic Substances ◽  
Anaerobic Degradation ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Priority Pollutants ◽  
Redox Mediators ◽  
Degradation Processes ◽  
Abiotic Degradation ◽  
Xenobiotic Degradation

Evidence is accumulating that inert humic substances can play important roles in the anaerobic degradation of priority pollutants by shuttling electrons. This paper reviews the roles of humus and quinone analogues as electron acceptors, redox mediators and electron donors for microbial and abiotic degradation processes. An eventual technology based on pumping quinones as terminal electron acceptors into aquifers and sediments to stimulate xenobiotic degradation offers promising potential. Also quinone redox mediators can be considered to accelerate reductive transformations (e.g. dechlorination, azo cleavage) of priority pollutants.

Recalcitrance as a catalyst for new developments

2001 ◽  
Vol 44 (8) ◽  
pp. 33-40 ◽  
Author(s):  
J.A. Field
Keyword(s):  
Molecular Weight ◽  
Humic Substances ◽  
Anaerobic Degradation ◽  
Electron Acceptors ◽  
Cell Uptake ◽  
Priority Pollutants ◽  
Redox Mediators ◽  
New Developments ◽  
Subsequent Exposure ◽  
Weight Structure

Humic substances are very recalcitrant in anaerobic environments as substrates, mostly due to their non-hydrolyzable high molecular weight structure, which is incompatible for cell uptake. The recalcitrant nature can be applied towards immobilizing pollutants into non-toxic humic substances. Certain anaerobic bioconversions such as demethylation of lignin and reduction of nitro- or azo groups can activate pollutants for humification processes upon subsequent exposure to air. Although humic substances provide no carbon or energy for microorganisms, the evidence presented here indicates that they are very active as terminal electron acceptors and redox mediators promoting the anaerobic degradation and biotransformation of priority pollutants.

The role of biotic and abiotic degradation processes during the formation of typical toxaphene peak patterns in aquatic biota

Chemosphere ◽  
1999 ◽  
Vol 39 (4) ◽  
pp. 563-568 ◽  
Author(s):  
D. Angerhöfer ◽  
L. Kimmel ◽  
G. Koske ◽  
G. Fingerling ◽  
J. Burhenne ◽  
...  
Keyword(s):  
Aquatic Biota ◽  
Degradation Processes ◽  
Abiotic Degradation

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

Distribution of Acidity and Alkalinity on Degraded Manuscripts Containing Iron Gall Ink

2015 ◽  
Vol 36 (3) ◽  
Author(s):  
Eva Marín ◽  
Maria Carme Sistach ◽  
Jessica Jiménez ◽  
Miguel Clemente ◽  
Guillem Garcia ◽  
...  
Keyword(s):  
Good Condition ◽  
Degradation Process ◽  
Degradation Processes ◽  
Alkaline Reserve ◽  
Hydrolysis Of Cellulose ◽  
Relevant Variables ◽  
Long Time ◽  
Iron Gall ◽  
The Stability

AbstractLong-time preservation of manuscripts depends on the stability of their support. One of the most important degradation processes of paper manuscripts containing iron gall ink is the acid hydrolysis of cellulose. The heterogeneity of the distribution of their constituent materials, together with the defined position of ink as a source of degradation agents, makes it difficult to obtain reliable and detailed information about degradation processes. The aim of this study is to contribute to the knowledge of the acid degradation process by looking at the distribution of relevant variables (pH, acidity and alkaline reserve) on real untreated iron gall ink containing manuscripts at different degradation stages. The study discusses the well-known differences between surface and cold extraction pH determination. It corroborates the relationship between pH, acidity and alkalinity and degradation stages, pointing out that acidity values for some manuscripts in apparent good condition are not far from those obtained for degraded manuscripts. The results indicate that in some partially degraded manuscripts, the coexistence of acid areas and areas with an alkaline reserve which do not participate in the neutralization process is possible. The role of water as a solvent for this equilibrium has also been evaluated.

scholarly journals Geobacter bemidjiensis sp. nov. and Geobacter psychrophilus sp. nov., two novel Fe(III)-reducing subsurface isolates

2005 ◽  
Vol 55 (4) ◽  
pp. 1667-1674 ◽  
Author(s):  
Kelly P. Nevin ◽  
Dawn E. Holmes ◽  
Trevor L. Woodard ◽  
Erich S. Hinlein ◽  
David W. Ostendorf ◽  
...  
Keyword(s):  
Type Strain ◽  
Novel Species ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Amorphous Iron ◽  
Gram Negative ◽  
Subsurface Sediments ◽  
Curved Rods ◽  
A Site

Fe(III)-reducing isolates were recovered from two aquifers in which Fe(III) reduction is known to be important. Strain BemT was enriched from subsurface sediments collected in Bemidji, MN, USA, near a site where Fe(III) reduction is important in aromatic hydrocarbon degradation. Strains P11, P35T and P39 were isolated from the groundwater of an aquifer in Plymouth, MA, USA, in which Fe(III) reduction is important because of long-term inputs of acetate as a highway de-icing agent to the subsurface. All four isolates were Gram-negative, slightly curved rods that grew best in freshwater media. Strains P11, P35T and P39 exhibited motility via means of monotrichous flagella. Analysis of the 16S rRNA and nifD genes indicated that all four strains are δ-proteobacteria and members of the Geobacter cluster of the Geobacteraceae. Differences in phenotypic and phylogenetic characteristics indicated that the four isolates represent two novel species within the genus Geobacter. All of the isolates coupled the oxidation of acetate to the reduction of Fe(III) [iron(III) citrate, amorphous iron(III) oxide, iron(III) pyrophosphate and iron(III) nitrilotriacetate]. All four strains utilized ethanol, lactate, malate, pyruvate and succinate as electron donors and malate and fumarate as electron acceptors. Strain BemT grew fastest at 30 °C, whereas strains P11, P35T and P39 grew equally well at 17, 22 and 30 °C. In addition, strains P11, P35T and P39 were capable of growth at 4 °C. The names Geobacter bemidjiensis sp. nov. (type strain BemT=ATCC BAA-1014T=DSM 16622T=JCM 12645T) and Geobacter psychrophilus sp. nov. (strains P11, P35T and P39; type strain P35T=ATCC BAA-1013T=DSM 16674T=JCM 12644T) are proposed.

Role of a phenothiazine/phenoxazine donor in solid ionic conductors for efficient solid state dye sensitized solar cells

2017 ◽  
Vol 5 (11) ◽  
pp. 5373-5382 ◽  
Author(s):  
Jayraj V. Vaghasiya ◽  
Keval K. Sonigara ◽  
Jyoti Prasad ◽  
Thomas Beuvier ◽  
Alain Gibaud ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Solar Cell ◽  
Solid State ◽  
Dye Sensitized Solar Cells ◽  
Electron Donors ◽  
Ionic Conductors ◽  
Good Thermal Stability ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Efficient electron donors, phenothiazine (PTZ)/phenoxazine (POZ) substituted imidazolium (IMI) and benzimidazolium (BIMI) iodide solid organic ionic conductors (SOICs) possessing good thermal stability and high conductivity are synthesized and used as electrolytes in solid state dye solar cell (ss-DSSC).

scholarly journals Phylogenetic and Functional Diversity of Saprolegniales and Fungi Isolated from Temperate Lakes in Northeast Germany

2021 ◽  
Vol 7 (11) ◽  
pp. 968
Author(s):  
Hossein Masigol ◽  
Jason Nicholas Woodhouse ◽  
Pieter van West ◽  
Reza Mostowfizadeh-Ghalamfarsa ◽  
Keilor Rojas-Jimenez ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Enzymatic Activity ◽  
Humic Substances ◽  
Plant Litter ◽  
Freshwater Ecosystems ◽  
Chitinolytic Activity ◽  
Ecological Implications ◽  
Eukaryotic Organisms

The contribution of fungi to the degradation of plant litter and transformation of dissolved organic matter (humic substances, in particular) in freshwater ecosystems has received increasing attention recently. However, the role of Saprolegniales as one of the most common eukaryotic organisms is rarely studied. In this study, we isolated and phylogenetically placed 51 fungal and 62 Saprolegniales strains from 12 German lakes. We studied the cellulo-, lignino-, and chitinolytic activity of the strains using plate assays. Furthermore, we determined the capacity of 10 selected strains to utilize 95 different labile compounds, using Biolog FF MicroPlates™. Finally, the ability of three selected strains to utilize maltose and degrade/produce humic substances was measured. Cladosporium and Penicillium were amongst the most prevalent fungal strains, while Saprolegnia, Achlya, and Leptolegnia were the most frequent Saprolegniales strains. Although the isolated strains assigned to genera were phylogenetically similar, their enzymatic activity and physiological profiling were quite diverse. Our results indicate that Saprolegniales, in contrast to fungi, lack ligninolytic activity and are not involved in the production/transformation of humic substances. We hypothesize that Saprolegniales and fungi might have complementary roles in interacting with dissolved organic matter, which has ecological implications for carbon cycling in freshwater ecosystems.

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