Background: Perchlorate contamination has been detected in both ground water and drinking water. An attractive treatment option is the use of ion-exchange to remove and concentrate perchlorate in brine. Biological treatment can subsequently remove the perchlorate from the brine. When nitrate is present, it will also be concentrated in the brine and must also be removed by biological treatment. The primary objective was to obtain an in-depth characterization of the microbial populations of two salt-tolerant cultures each of which is capable of metabolizing perchlorate. The cultures were derived from a single ancestral culture and have been maintained in the laboratory for more than 10 years. One culture was fed perchlorate only, while the other was fed both perchlorate and nitrate.
Results: A metagenomic characterization was performed using Illumina DNA sequencing technology, and the 16S rDNA of several pure strains isolated from the mixed cultures were sequenced. In the absence of nitrate, members of the Rhodobacteraceae constituted the prevailing taxonomic group. Second in abundance were the Rhodocyclaceae. In the nitrate fed culture, the Rhodobacteraceae are essentially absent. They are replaced by a major expansion of the Rhodocyclaceae and the emergence of the Alteromonadaceae as a significant community member. Gene sequences exhibiting significant homology to known perchlorate and nitrate reduction enzymes were found in both cultures.
Conclusions: The structure of the two microbial ecosystems of interest has been established and some representative strains obtained in pure culture. The results illustrate that under favorable conditions a group of organisms can readily dominate an ecosystem and yet be effectively eliminated when their advantage is lost. Almost all known perchlorate-reducing organisms can also effectively reduce nitrate. This is certainly not the case for the Rhodobacteraceae that were found to dominate in the absence of nitrate, but effectively disappeared in its presence. This study is significant in that it reveals the existence of a novel group of organisms that play a role in the reduction of perchlorate under saline conditions. These Rhodobacteraceae especially, as well as other organisms present in these communities may be a promising source of unique salt-tolerant enzymes for perchlorate reduction.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4174249 | PMC |
http://dx.doi.org/10.1186/s12866-014-0225-3 | DOI Listing |
Inorg Chem
January 2025
School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Zwitterionic energetic materials offer a unique combination of high performance and stability, yet their synthesis and stability enhancement remain key challenges. In this study, we report the synthesis of a highly stable (dinitromethyl-functionalized zwitterionic compound, 1-(amino(iminio)methyl)-4,5-dihydro-1H-pyrazol-5-yl)dinitromethanide (), with a thermal decomposition temperature of 215 °C, surpassing that of most previously reported energetic monocyclic zwitterions ( < 150 °C). This compound was synthesized via intramolecular cyclization of a trinitromethyl-functionalized hydrazone precursor.
View Article and Find Full Text PDFDalton Trans
January 2025
School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, 330031, People's Republic of China.
Three-component crown ether phase change materials are characterized by a structural phase change in response to external stimuli such as temperature and electric or magnetic fields, resulting in significant changes in physical properties. In this work, we designed and synthesized two novel host-guest crown ether molecules [(PTFMA)(15-crown-5)ClO] (1) and [(PTFMA)(15-crown-5)PF] (2), through the reaction of -trifluoromethylaniline (PTFMA) with 15-crown-5 in perchloric acid or hexafluorophosphoric acid aqueous solution. Compound 1 undergoes a structural change from the non-centrosymmetric space group (2) to the centrosymmetric space group (2/) with increasing temperature.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, United States.
Solid-state polymer electrolytes (SPEs) are increasingly favored over liquid electrolytes for emerging energy storage devices due to their safety features, enhanced stability, and multifunctionality. Minor solvents (such as water) are often introduced unintentionally or intentionally into SPEs. Although it can significantly affect SPEs' electrochemical and mechanical properties, the fundamental role of such solvent content has rarely been studied.
View Article and Find Full Text PDFChemosphere
January 2025
Department of Environmental Science, Baylor University, Waco, TX, USA. Electronic address:
Background: Perchlorate, nitrate, and thiocyanate are well-known sodium/iodide symporter (NIS) inhibitors that disturb iodide uptake at the thyroid, affecting thyroid function. However, the associations between NIS inhibitor exposure and thyroid function are not well summarized in humans.
Objective: We aimed to summarize associations between NIS inhibitor exposure and thyroid function markers and to identify key information gaps for future studies.
Polymers (Basel)
January 2025
Centre for Advanced Devices and Systems, Faculty of Engineering, Multimedia University, Persiaran Multimedia, Cyberjaya 63100, Selangor, Malaysia.
Electrochromic devices (ECDs) are devices that change their optical properties in response to a low applied voltage. These devices typically consist of an electrochromic layer, a transparent conducting substrate, and an electrolyte. The advancement in solid-state ECDs has been driven by the need for improved durability, optical performance, and energy efficiency.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!