scholarly journals Isolation and Molecular identification of native As-resistant bacteria: As(III) and As(V) removal capacity and possible mechanism of detoxification

Author(s):  
Ulises Emiliano Rodriguez-Castrejón ◽  
Alma Hortensia Serafin-Muñoz ◽  
Aurelio Alvarez-Vargas ◽  
Gustavo Cruz Jimenez ◽  
Berenice Noriega-Luna

Abstract The study of arsenic resistant microorganisms with high arsenic removal capacity is fundamental for the development of economically sustainable technologies for the treatment of water contaminated with this metalloid. In this work, the isolation and identification of 4 native strains was carried out.: Rhodococcus gordoniae, Microbacterium hydrocarbonoxydans, Exiguobacterium indicum and Pseudomonas kribbensis . R.gordoniae was identified as the bacterium with the highest growth capacity in both As(III) and As(V). E.indicum removed about 74.8% of Arsenate, As(V), and 61.7% of Arsenite , As(III), while R.gordoniae removed about 81.6 % of As(III), and 77.2% of As(V), while that M.hydrocarbonoxydans was able to remove up to 79.9% of As(III) and 68.9% of As(V). Finally, it was observed that P. kribbensis removed about 80.2% of As(V). This study also contributes to the possible detoxification mechanisms employed by these bacteria, the knowledge of which could be crucial in the successful implementation of in situ bioremediation programs.

2011 ◽  
Vol 185 (2-3) ◽  
pp. 990-995 ◽  
Author(s):  
Kun Wu ◽  
Hongjie Wang ◽  
Ruiping Liu ◽  
Xu Zhao ◽  
Huijuan Liu ◽  
...  

2016 ◽  
Vol 3 (1) ◽  
pp. 94-106 ◽  
Author(s):  
Wei Li ◽  
Dehong Chen ◽  
Fang Xia ◽  
Jeannie Z. Y. Tan ◽  
Pei-Pei Huang ◽  
...  

Mesoporous aluminium magnesium oxide composites exhibit extremely high adsorption capacities for As(v) and As(iii) with excellent environmental adaptability and selectivity.


Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 928
Author(s):  
Micah Flor V. Montefalcon ◽  
Meliton R. Chiong ◽  
Augustus C. Resurreccion ◽  
Sergi Garcia-Segura ◽  
Joey D. Ocon

Arsenic (As) is a naturally occurring element in the environment that poses significant risks to human health. Several treatment technologies have been successfully used in the treatment of As-contaminated waters. However, limited literature has explored advanced electrocoagulation (EC) processes for As removal. The present study evaluates the As removal performance of electrocoagulation, electrochemical peroxidation (ECP), and photo-assisted electrochemical peroxidation (PECP) technologies at circumneutral pH using electroactive iron electrodes. The influence of As speciation and the role of oxidants in As removal were investigated. We have identified the ECP process to be a promising alternative for the conventional EC with around 4-fold increase in arsenic removal capacity at a competitive cost of 0.0060 $/m3. Results also indicated that the rate of As(III) oxidation at the outset of electrochemical treatment dictates the extent of As removal. Both ECP and PECP processes reached greater than 96% As(III) conversion at 1 C/L and achieved 86% and 96% As removal at 5 C/L, respectively. Finally, the mechanism of As(III) oxidation was evaluated, and results showed that Fe(IV) is the intermediate oxidant generated in advanced EC processes, and the contribution of •OH brought by UV irradiation is insignificant.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer Zehner ◽  
Anja Røyne ◽  
Pawel Sikorski

AbstractBiocementation is commonly based on microbial-induced carbonate precipitation (MICP) or enzyme-induced carbonate precipitation (EICP), where biomineralization of $$\text {CaCO}_{3}$$ CaCO 3 in a granular medium is used to produce a sustainable, consolidated porous material. The successful implementation of biocementation in large-scale applications requires detailed knowledge about the micro-scale processes of $$\text {CaCO}_{3}$$ CaCO 3 precipitation and grain consolidation. For this purpose, we present a microscopy sample cell that enables real time and in situ observations of the precipitation of $$\text {CaCO}_{3}$$ CaCO 3 in the presence of sand grains and calcite seeds. In this study, the sample cell is used in combination with confocal laser scanning microscopy (CLSM) which allows the monitoring in situ of local pH during the reaction. The sample cell can be disassembled at the end of the experiment, so that the precipitated crystals can be characterized with Raman microspectroscopy and scanning electron microscopy (SEM) without disturbing the sample. The combination of the real time and in situ monitoring of the precipitation process with the possibility to characterize the precipitated crystals without further sample processing, offers a powerful tool for knowledge-based improvements of biocementation.


2007 ◽  
Vol 24 (5) ◽  
pp. 707-715 ◽  
Author(s):  
Ruiping Liu ◽  
Jiuhui Qu ◽  
Shengji Xia ◽  
Gaosheng Zhang ◽  
Guibai Li

2021 ◽  
Vol 27 ◽  
Author(s):  
Jewel Ju Ea Kim ◽  
Ildikó Kocsmár ◽  
György Miklós Buzás ◽  
Ildikó Szirtes ◽  
Orsolya Rusz ◽  
...  

The global rise in clarithromycin (Cla) resistance is considered to be the main contributor of Helicobacter pylori (Hp) eradication failures. In nearly half of the Cla-resistant Hp infections, Cla-susceptible bacteria are simultaneously present with the Cla-resistant ones (Cla-heteroresistance). The proportion of resistant bacteria in the bacterial population (R-fraction) and its predictive role for the use of Cla-based therapies in Cla-heteroresistant infections has not yet been investigated. Our retrospective study analyzed gastric biopsy samples of 62 Hp-positive patients with Cla-heteroresistant infection. Fluorescence In Situ Hybridization technique was used to visualize the coexistence of resistant and susceptible bacteria within one tissue sample. R-fraction was quantified on multichannel microimages by digital morphometry. Resistant bacteria had a patchy distribution within the whole bacterial population causing high diversity among the investigated areas. Patients were subdivided into two major groups according to whether a Cla-based eradication attempt was conducted before or after the biopsy sampling. R-fraction was significantly lower among cases having only one previous Cla-based eradication attempt vs. those that had multiple previous eradications, including at least one Cla-containing therapy (0.41 vs. 0.89, p = 0.0308). Majority of the patients without previous eradication attempt had successful eradication with Cla-containing regimen (59.26%), verified by a negative 13C-urea breath test or control biopsy. Multivariable model indicated that the therapeutic outcome using Cla-based regimens depended on the bacterial density rather than the R-fraction. Our study raises the potential use of Cla-containing eradication therapies in certain Cla-heteroresistant Hp infections, taking into account the possible predictive role of bacterial density.


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