Arsenite Oxidation

The article presents the results of studies conducted in recent years. These studies aimed to determine the
concentrations of heavy metals in biological samples (mainly corn) growing in Georgia. This plant species was chosen because
both domestic animals and humans consume it. Samples were collected from corn fields near roads and highways to determine
the maximum concentrations of heavy metals in biological samples. For ease of comparison, the results are presented in
graphical form separately for Western and Eastern Georgia. High concentrations of heavy metals and toxic elements are
observed in corn fields in different regions.

NT-26 is a chemolithoautotrophic arsenite oxidizer. Understanding the mechanisms of arsenite signalling, tolerance and oxidation by NT-26 will have significant implications for its use in bioremediation and arsenite sensing. We have identified the histidine kinase (AroS) and the cognate response regulator (AroR) involved in the arsenite-dependent transcriptional regulation of the arsenite oxidase aroBA operon. AroS contains a single periplasmic sensory domain that is linked through transmembrane helices to the HAMP domain that transmits the signal to the kinase core of the protein. AroR belongs to a family of AAA1 transcription regulators that interact with DNA through a helix-turn-helix domain. The presence of the AAA1 domain as well as the RNA polymerase s 54-interaction sequence motif suggests that this protein regulates transcription through interaction with RNA polymerase in a s 54-dependent fashion. The kinase core of AroS and the receiver domain of AroR were heterologously expressed and purified and their autophosphorylation and transphosphorylation activities were confirmed. Using site-directed mutagenesis, we have identified the phosphorylation sites on both proteins. Mutational analysis in NT-26 confirmed that both proteins are essential for arsenite oxidation and the AroS mutant affected growth with arsenite, also implicating it in the regulation of arsenite tolerance. Lastly, arsenite sensing does not appear to involve thiol chemistry.

NT-26 is a chemolithoautotrophic arsenite oxidizer. Understanding the mechanisms of arsenite signalling, tolerance and oxidation by NT-26 will have significant implications for its use in bioremediation and arsenite sensing. We have identified the histidine kinase (AroS) and the cognate response regulator (AroR) involved in the arsenite-dependent transcriptional regulation of the arsenite oxidase aroBA operon. AroS contains a single periplasmic sensory domain that is linked through transmembrane helices to the HAMP domain that transmits the signal to the kinase core of the protein. AroR belongs to a family of AAA1 transcription regulators that interact with DNA through a helix-turn-helix domain. The presence of the AAA1 domain as well as the RNA polymerase s 54-interaction sequence motif suggests that this protein regulates transcription through interaction with RNA polymerase in a s 54-dependent fashion. The kinase core of AroS and the receiver domain of AroR were heterologously expressed and purified and their autophosphorylation and transphosphorylation activities were confirmed. Using site-directed mutagenesis, we have identified the phosphorylation sites on both proteins. Mutational analysis in NT-26 confirmed that both proteins are essential for arsenite oxidation and the AroS mutant affected growth with arsenite, also implicating it in the regulation of arsenite tolerance. Lastly, arsenite sensing does not appear to involve thiol chemistry.

Rice is one of the most widely consumed grain crops (besides wheat and maize) in Iran and various countries. Currently, more and more rice is found to be contaminated with heavy metals, which can have a negative impact on human health. The current study aimed to investigate the impact of coffee bean waste (CBW) and Rice Husk ( RH) as bio-adsorbent in reducing Lead, Arsenic, Cadmium, and Nickel in rice (Oryza Sativa). 950 rice samples were collected from various markets in Tehran to extract the heavy metal content in raw, rinsed, soaked with adsorbent, and cooked and drained rice, determined and measured by wet digestion method. Final concentrations of heavy metals in rice samples were analyzed using Inductively Coupled Plasma Optical Emission Spectroscopy according to AOAC International Standards. Batch adsorption experiments were carried out to evaluate the effect of adsorbent dosing, sample state, and ionic strength of solutions on the adsorption of heavy metals onto bio-adsorbents collected simply from legumes and homemade waste at room temperature and then dried at 65 C0 and ground to size mesh 80-100 microns. Arsenic was not found in the samples studied. The cadmium content of the samples was removed through cooking and treated with a mixture of certain percentages of CBW and RH. The content of Lead and Nickel decreased significantly (p<0.05) in all cooking methods. The weekly cadmium intake in bulk and unprocessed packaged rice samples is higher than that of Iranian national standards. Still, with the new eco-friendly detoxification method, there is no risk under any cooking conditions and no food contamination. The current research findings indicate that Food/Agro waste can be utilized profitably in processing rice containing heavy metal ions.

The alphaproteobacterial family Rhizobiaceae is highly diverse, with 168 species with validly published names classified into 17 genera with validly published names. Most named genera in this family are delineated based on genomic relatedness and phylogenetic relationships, but some historically named genera show inconsistent distribution and phylogenetic breadth. The most problematic is Rhizobium, which is notorious for being highly paraphyletic, as most newly described species in the family are assigned to this genus without consideration of their proximity to existing genera, or the need to create novel genera. Moreover, many Rhizobiaceae genera lack synapomorphic traits that would give them biological and ecological significance. We propose a common framework for genus delimitation within the family Rhizobiaceae, wherein genera are defined as monophyletic groups in a core-genome gene phylogeny, that are separated from related species using a pairwise core-proteome average amino acid identity (cpAAI) threshold of approximately 86 %. We further propose that additional genomic or phenotypic evidence can justify division of species into separate genera even if they share greater than 86 % cpAAI. Applying this framework, we propose to reclassify Rhizobium rhizosphaerae and Rhizobium oryzae into Xaviernesmea gen. nov. Data is also provided to support the formation of Peteryoungia aggregata comb. nov., Endobacterium yantingense comb. nov., Neorhizobium petrolearium comb. nov., Pararhizobium arenae comb. nov., Pseudorhizobium tarimense comb. nov. and Mycoplana azooxidifex comb. nov. Lastly, we present arguments that the unification of the genera Ensifer and Sinorhizobium in Opinion 84 of the Judicial Commission is no longer justified by current genomic and phenotypic data. Despite pairwise cpAAI values for all Ensifer species and all Sinorhizobium species being >86 %, additional genomic and phenotypic data suggest that they significantly differ in their biology and ecology. We therefore propose emended descriptions of Ensifer and Sinorhizobium, which we argue should be considered as separate genera.

ABSTRACTThe alphaproteobacterial family Rhizobiaceae is highly diverse, with 168 species with validly published names classified into 17 genera with validly published names. Most named genera in this family are delineated based on genomic relatedness and phylogenetic relationships, but some historically named genera show inconsistent distribution and phylogenetic breadth. Most problematic is Rhizobium, which is notorious for being highly paraphyletic, as most newly described species in the family being assigned to this genus without consideration for their proximity to existing genera, or the need to create novel genera. In addition, many Rhizobiaceae genera lack synapomorphic traits that would give them biological and ecological significance. We propose a common framework for genus delimitation within the family Rhizobiaceae. We propose that genera in this family should be defined as monophyletic groups in a core-genome gene phylogeny, that are separated from related species using ...

Allorhizobium vitis (formerly named Agrobacterium vitis or Agrobacterium biovar 3) is the primary causative agent of crown gall disease of grapevine worldwide. Whole-genome sequence comparisons and phylogenomic analysis of various All. vitis strains clearly indicated that All. vitis is not a single species, but represents a species complex composed of at least four genomic species. Thus, we amended the description of All. vitis which now refers to a restricted group of strains within the All. vitis complex (i.e. All. vitis sensu stricto) and proposed a description of a novel species All. ampelinum sp. nov. The type strain of All. vitis sensu stricto remains the existing type strain of All. vitis, K309T (= NCPPB 3554T =HAMBI 1817T = ATCC 49767T = CIP 105853T = ICMP 10752T = IFO 15140T = JCM 21033T = LMG 8750T = NBRC 15140T). The type strain of All. ampelinum sp. nov. is S4T (= DSM 112012T = ATCCBAA-846T). This genome-based classification was supported by differentiation of strains ba...

Arsenic, cadmium, and lead are three non-vital heavy metals that are harmful to the environment, food safety, and the health of both humans and animals whenever present in excessive quantities. Poisonous metals and metalloid soil can be found worldwide. In higher amounts, some may cause neurological and behavioral abnormalities, particularly in children, while others are endocrine disruptors, carcinogens, teratogens, and mutagenic. The prevention, control, and remediation of heavy metal contamination have grown to be a top national priority in light of the real situation with soil pollution in our nation. To eliminate this kind of pollution, a variety of procedures have been used, including chemical, physical, biological, and integrative methods. Using plants and associated soil bacteria, phytoremediation lowers pollutant concentrations or their hazardous effects on the environment. It is a relatively new method that has gained widespread appeal for being an affordable, effective, unique and environmentfriendly technique. The distribution of heavy metals in the environment, their sources, and the ecotoxicity they have on the environment are thoroughly explained in this review paper. Some of the procedures for creating heavy metal-free soil by using various soil remediation techniques are also described.

Millions of people worldwide are at risk of arsenic poisoning from their drinking water. In Bangladesh the problem extends to rural drinking water wells, where non-biological solutions are not feasible. In serial enrichment cultures of water from various Bangladesh drinking water wells, we found transfer-persistent arsenite oxidation activity under four conditions (aerobic/anaerobic; heterotrophic/autotrophic). This suggests that biological decontamination may help ameliorate the problem. The enriched microbial communities were phylogenetically at least as diverse as the unenriched communities: they contained a bonanza of 16S rRNA gene sequences. These related to Hydrogenophaga, Acinetobacter, Dechloromonas, Comamonas, and Rhizobium/Agrobacterium species. In addition, the enriched microbiomes contained genes highly similar to the arsenite oxidase (aioA) gene of chemolithoautotrophic (e.g., Paracoccus sp. SY) and heterotrophic arsenite-oxidizing strains. The enriched cultures also co...

The Dutch drinking water sector is actively investigating methods to reduce arsenic (As) to < 1 μg/L in drinking water supply. We investigated (1) the effectiveness of sequential permanganate (MnO 4¯) eferric (Fe(III)) dosing during aerationerapid sand filtration to achieve < 1 μg/L As (2) the influence of MnO 4¯e Fe(III) dosing on preestablished removal patterns of As(III), Fe(II), Mn(II) and NH 4 + in rapid sand filters and (3) the influence of MnO 4¯e Fe(III) dosing on the settling and molecular-scale structural properties of the filter backwash solids. We report that MnO 4¯e Fe(III) dosing is an effective technique to improve arsenite [As(III)] removal at groundwater treatment plants. At a typical aeration-rapid sand filtration facility in the Netherlands effluent As concentrations of < 1 μg/L were achieved with 1.2 mg/L MnO 4¯e and 1.8 mg/L Fe(III). The optimized combination of MnO 4¯e and Fe(III) doses did not affect the removal efficiency of Fe(II), Mn(II) and NH 4 + in rapid sand filters, however, the removal patterns of Fe(II) and Mn(II) in rapid sand filter were altered, as well as the settling behaviour of backwash solids. The characterization of backwash solids by Fe K-edge X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) showed that the changed settling velocity of backwash solids with MnO 4¯e Fe(III) in place was not due to changes in the molecular-scale structure of Fe-precipitates that constitute the major portion of the backwash solids.

El proceso de reacreditacion del Master de Ingenieria de Caminos, Canales y Puertos, que se ha llevado a cabo los dias 7 y 8 de Junio de 2017 por parte de la Agencia Valenciana de Evaluacion y Prospectiva (AVAP), ha permitido obtener una vision general de los resultados obtenidos en los ultimos anos en las distintas asignaturas que conforman el Plan de Estudios de la titulacion que se inicio, en la Universidad de Alicante, en el curso academico 2014-15. Como parte previa a este procedimiento y con aplicacion directa en el presente trabajo, se han analizado las distintas asignaturas de la titulacion, asi como en el Trabajo Fin de Master, que ejerce como compendio de las competencias adquiridas por los alumnos a lo largo del proceso de aprendizaje. El analisis se centrara tanto en las asignaturas troncales de la titulacion (en especial, en aquellas que aportan una mayor carga conceptual tanto desde el punto de vista teorico como de aplicacion practica, al ser las que tengan una mayor ...

Allorhizobium vitis (formerly named Agrobacterium vitis or Agrobacterium biovar 3) is the primary causative agent of crown gall disease of grapevine worldwide. Whole-genome sequence comparisons and phylogenomic analysis of various All. vitis strains clearly indicated that All. vitis is not a single species, but represents a species complex composed of at least four genomic species. Thus, we amended the description of All. vitis which now refers to a restricted group of strains within the All. vitis complex (i.e. All. vitis sensu stricto) and proposed a description of a novel species All. ampelinum sp. nov. The type strain of All. vitis sensu stricto remains the existing type strain of All. vitis, K309T (= NCPPB 3554T =HAMBI 1817T = ATCC 49767T = CIP 105853T = ICMP 10752T = IFO 15140T = JCM 21033T = LMG 8750T = NBRC 15140T). The type strain of All. ampelinum sp. nov. is S4T (= DSM 112012T = ATCC BAA-846T). This genome-based classification was supported by differentiation of strains b...

The oxidation and treatment of arsenite [As(III)] with ultrasound (US) and Fe(II) was investigated in aqueous solutions. The oxidation of As(III) into As(V), over 99.1%, was obtained by US 450kHz. The kinetics of As(III) oxidation were interpreted using the modified pseudo-first-order kinetic model. The half life of As(III) was approximately 3:47 Â 10 À2 s for the US 450kHz /Fe(II) 0:4mg=L reaction and depended on the iron concentration. The arsenic removal capacity of complexed and coprecipitated FeAsO 4 (s) was estimated to be 16.12 mg per g of iron oxide. It is concluded that the sonochemical treatment of As(III) solution in the presence of Fe(II) is a simple and viable technique for the oxidation of As(III) into arsenate [As(V)] and the treatment of total arsenic.

Every year there is deterioration in water quality. This is due to human activity. The current environmental strategies of many countries motivate the scientific community to develop reliable, economically viable and environmentally friendly technologies that are able to remove pollutants from the environment, including water. The study purpose is to determine of influence regularity of the bio-adsorbent composition and amount, which consists of red and black tea leaves mixture, on the Cd, Co and Ni adsorption process based on experimental data. As well as determine the most rational bio-adsorbent dose and the necessary red and black tea dose in bio-adsorbent to achieve MPC of heavy metals, with which process duration will be minimal. Initially, to study the adsorption process kinetics, the nature of the curve that describes the obtained experimental values was visually analyzed. To determine the adsorption process kinetic regularity, which most adequately and reliably describes the experimental data and to determine the values of the coefficients in the exponential regularity, the least squares method was used. It was observed that for Cd and Co, an increase in the black and red tea amount leads to a drastic reduction of the adsorption process time (up to 10 times); while for Ni the black tea addition slows down the adsorption process. Ni adsorption is the most complex and for certain bio-adsorbent composition values, complete Ni removal cannot be achieved in a technologically reasonable adsorption time. The technological process of Cd, Co and Ni adsorption can be expedient, if it is carried out in several stages with optimal red and black tea amounts for each of the metals. Adsorption process kinetic regularity, which was determined, can be used to calculate of adsorption process technological parameters in values wide range.

The heavy metals pollution among various types of contaminations is a serious hazard for environment and human health. Different methods of removing heavy metals have different advantages and disadvantages, among them biological techniques of absorption/ adsorption have been considered. The main benefits of biological absorption, compared with the conventional methods, are low cost, high efficiency, reducing chemical and/or environmental sludge, no need for additional nutrients, and the possibility of recycling of metals. The absorption of heavy metals by microbial cells is recognized as a potential alternative to existing technologies of removal of toxic heavy metals using waste from the food industry and agricultural wastes as bio-absorbs. Therefore, the main the goal of this article is evaluate the potential and advisability and effectiveness of using food industry waste and agricultural waste to remove or significantly reduce toxic heavy metals from contaminated food and water. And also to study the mechanisms of using of waste from the food industry and agricultural wastes as bio-absorbs to determine the best option of using, what would improve it. To achieve the goal, the work has been studied and analyzed all attainable sources of agro based lowcost reasonable adsorbents for their feasibility in the removal of heavy metals from food stuff and contaminated water. Since most of the researches have been carried out in pilot form and has not been tested at the industrial level, then it is necessary to improve these methods for their implementation and utilization in the treatment of the industrial contaminated water and also food products. From the analysis it is evident that the most attractive as bio-absorbs are such materials such as potato peel, sawdust, citrus peels, mango peel, corn cob, rice husk, tree fern, wheat bran, grape bagasse, coconut copra meal, orange waste, walnut, hazelnut, almond shell, tea waste. And especially the use of these materials is attractive from the economic point of view as the most affordable and cheap.

Due to the low dietary value of crops, Zn-deficient soils and insufficient intake of other minerals, soil fortification is often necessary. Fortification is defined as the addition of one or more crucial nutrients to a food to reduce poverty in a population or specific population groups. Currently available technologies for rice fortification with vitamins and minerals are high-energy and time-consuming methods. Therefore, mineral enrichment of crops has received much attention from scientists. The originality of the current study consists in determining the optimal use of hard hazelnut shells, orange peel and rice husks for enrichment of paddy soil and simultaneous immobilization of heavy metals. The combination of the identified wastes, namely hazelnut shells, orange peel and rice husks, showed good potential for immobilization/elimination or reduction of heavy metals to less than permissible limits. Therefore, the use of this combination could be an effective strategy to both int...

The programs of managing waste materials in developing countries are often unsatisfactory and the unreasonable disposal of waste is a major issue in the worldwide. The main aim of the current study is to: Assess the applicability of Rumex crispus L. in removing heavy metals from the contaminated wastewater effluent form Pharmaceutical laboratories by bio-adsorption method. The dried R. crispus L. seeds were purchased from recognized herbal plant markets randomly in Tehran in May 2016 in order to investigate the influence of R. crispus seeds as an amendment to remove or decrease chemical forms of Co, Pb, Cu, Zn and Ni. Experimental parameter were as follows: pH, temperature, dose of bio-adsorbent R. crispus L. seeds, contact time, particle size mesh were studied. Results revealed that bio-adsorption capacity of Lead, Zinc, Copper, Cobalt and Nickel increases with increasing initial adsorbent concentration and reaches at maximum after a 2% initial concentration of S. incisa seeds conc...

Research was carried out to remove arsenic from synthetic AMD, raising the pH of the solution and using waste material for food processing by adsorbing arsenic to recover impurities. Arsenite can be quickly converted into arsenate, the more thermodynamically stable. Attention was paid to biomaterials, which are by-products or agricultural waste. Zizyphus seeds were used for this purpose as cheaper and often available food waste materials, due to the potential sorption capacity of arsenic. In order to clean the soils in contaminated towns and mining districts, establish its adsorption potential and enable food production in these areas, collective soil samples were taken from a depth of 0 – 40 cm from the area of 5 cities and 10 sub-regions of Anguran, province Zanjan in Iran. In the trials, the amount of As(III) and/or arsenate(V) in the soil was evaluated. Their content was tested using ICP-MS. The adsorption process was significantly dependent on adsorbent concentrations and also ...

Background: Pharmaceutical waste effluent could be dumped into a sink and if these chemical compounds are not biodegraded or eliminated during sewage treatment, they eventually reach drinking water. Objectives: Chamomile as a one of the most common herbal teas people drink was chosen for adsorbing the heavy metals from pharmaceutical effluent. Materials and Methods: Pharmaceutical research laboratories effluent samples in 2016 were collected and added to the soil. Meanwhile the residue of Chamomile tea in different concentrations added as an adsorbent in contaminated soil and Basil as an edible vegetable has been grown in these soil samples. The soil leaves and roots of basil samples under different experimental conditions have been studied after every 10 days in 60 days and digested by wet method according the standard protocol. The data were analyzed using Analysis of Variance, (ANOVA). Results: Results revealed that Chamomile residue have more potential to adsorb Nickel and Cadmium first days of study (p<0.001) and adsorption capacity varied by considering the effects of various parameters like contact time, initial concentrations, pH, temperature, absorbent dose. Chamomile can accumulate high level of Cadmium in a short time and the uptake rate by vegetable edible plant is significantly affected by their concentrations in the contaminated soil (p<0.05). Conclusion: A contact time of 30 days by 5% Chamomile was found to be optimum and 41% of Ni was taken by 15% adsorbent from contaminated soil while a few amounts of these heavy metals being uptake by leaves of edible vegetable basil.

Water resources is one of the most important environmental problems of countries. Up to now various methods of removing of these metals is considered, which is including using of low prices materials. In this study the potential of two wild endemic almond: Amygdalus lycioides and Amygdalus wendelboi shells was assessed for adsorption of heavy metal ions such as Ni 2+ , Cr 6+ and Cr 3+ from aqueous solution. A. lycioides and A. wendelboi fruits were collected in June 2013 from Sirmand Mountains near Hadji-Abad County, Hormozgan Province and the mountains in Gnow protected area, Bandar-Abbas, Hormozgan Province in Iran respectively. The analyzing for Ni and Cr (III) and Cr (VI) concentrations using inductively coupled plasmaatomic emission spectrometry (ICP-AES). Adsorption capacity of Cr(VI), Cr(III) and Ni onto modified almond shells by Phosphoric acid was investigated in a batch system by considering the effects of various parameters like contact time, initial concentrations, pH , temperature, absorbent dose and particle size. The adsorption was pH solution dependent and the maximum adsorption was observed at solution pH of 3.2. The amounts of Cr(VI) adsorbed increased significantly with increase in dose of A. wendelboi adsorbent (p<0.02) and their contact time (p<0.05). The results of this study revealed that A. lycioides and A. wendelboi can accumulate high level of Chrome (VI) and (III) in a short time and their uptake rate by plant is significantly affected by their concentrations in the contaminated water (p<0.005). A contact time of 48 by both almond shells was found to be optimum and 83.6% Cr(VI), 90.2% Cr(III)and 94.1% Ni was removed. Experimental results show low cost biosorbent was effective for the removal of pollutants from aqueous solution.

There are very few studies evaluating the heavy metals and nitrate contents in their soils and groundwater in the north provinces and cities in Iran although majority of rice, tea and other crops comes from these location. Dangerous contents of Cadmium and Lead could been found in recent years in Mazandaran and Gilan agricultural products due to contaminated source tapped to address population and over fertilization with chemical fertilizers and high rain falling.A descriptive – analytical and cross-sectional study was conducted for determination of Lead and Cadmium as heavy metals and nitrate in 100 samples of ground water and soil of 10 different sites in Talesh in the North of Iran in three consequent months in (winter and spring;summer, 2013). The results revealed that all samples in panjahaft had lead and nitrate contents above maximum level 0.01 mg/L and 50 mg/L which is recommended by WHO (WHO, 2007; US/EPA, 2013) and Lead was present in detectable amounts in all samples whil...

Removing arsenic by food-processing waste (Zizyphus jujuba seeds) and study on its adsorptive properties. Technogenic and ecological safety, 5(1/2019), 62-70. Abstract Research was carried out to remove arsenic from synthetic AMD, raising the pH of the solution and using waste material for food processing by adsorbing arsenic to recover impurities. Arsenite can be quickly converted into arsenate, the more thermodynamically stable. Attention was paid to biomaterials, which are by-products or agricultural waste. Zizyphus seeds were used for this purpose as cheaper and often available food waste materials, due to the potential sorption capacity of arsenic. In order to clean the soils in contaminated towns and mining districts, establish its adsorption potential and enable food production in these areas, collective soil samples were taken from a depth of 0-40 cm from the area of 5 cities and 10 sub-regions of Anguran, province Zanjan in Iran. In the trials, the amount of As(III) and/or arsenate(V) in the soil was evaluated. Their content was tested using ICP-MS. The adsorption process was significantly dependent on adsorbent concentrations and also time. The efficiency and the complicated mechanism of the uptake of Arsenic ions onto the soils depend on the concentration of cellular surface of the Jujube seed powder and also the time of being interaction. 10 % of Jujube seed attained maximum removal all Arsenic ions in this study. Significant differences in decreasing toxic metal were observed among the time of 48 hours and 1 week in all concentrations of bio-adsorbent. The maximum adsorption of toxic metals varied between 80 and 90 % depending on the contact time, stirring action and concentrations of studied bio-adsorbent Ziziphus jujuba seeds. With higher biomass doses the removal efficiency of As was higher even at the same time of being contact. Authors suggest more studies on the mechanism in the next projects and utilizing other dead bio-masses.

—Aiming at accurately and rapidly identifying our heavy metal resistant rhizobial strains, genomic average nucleotide identity (ANI) and core genome analyses were performed to investigate the phylogenetic relationships among 45 strains in the families of Rhizobiaceae and Bradyrhizobiaceae. The results showed that both of the ANI and core-genome phylogenetic trees revealed similar relationship. In ANI analysis, the 90%, 75% and 70% ANI values could be the thresholds for species, genus and family, respectively. Analyzing the genomes using multi-dimensional scaling and scatter plot showed highly consistent with the ANI and core-genome phylogenetic results. With these thresholds, the 45 strains were divided into 24 genomic species within the genera Agrobacterium, Allorhizobium, Bradyrhizobium, Sinorhizobium and a putative novel genus represented by Ag. albertimagni AOL15. The ten arsenite-oxidizing and antimonite tolerant strains were identified as Ag. radiobacter, and two Sinorhizobium genomic species differing from S. fredii. In addition, the description of Pararhizobium is questioned because ANI values greater than 75% were detected between P. giardinii H152T and Sinorhizobium strains. Also, reversion of the species definition for several strains in R. etli and R. leguminosarum was suggested. Our results demonstrate that analyses of ANI and core-genome are rapid and confident methods to identify the rhizobial strains, and it will be also convenient when more genome data are accumulated.

The oxidation and treatment of arsenite [As(III)] with ultrasound (US) and Fe(II) was investigated in aqueous solutions. The oxidation of As(III) into As(V), over 99.1%, was obtained by US450kHz. The kinetics of As(III) oxidation were interpreted using the modified pseudo-first-order kinetic model. The half life of As(III) was approximately 3.47 × 10-2 for the US450kHz/Fe(II)0:4mg/L reaction and depended on the iron concentration. The arsenic removal capacity of complexed and coprecipitated FeAsO4(s) was estimated to be 16.12mg per g of iron oxide. It is concluded that the sonochemical treatment of As(III) solution in the presence of Fe(II) is a simple and viable technique for the oxidation of As(III) into arsenate [As(V)] and the treatment of total arsenic. © 2011 The Japan Society of Applied Physics.

https://getinfo.de/app/Arsenite-Oxidation-and-Treatment-by-Ultrasound/id/BLCP%3ACN080123915 
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