Biodegradation of microcystin-LR using acclimatized bacteria isolated from different units of the drinking water treatment plant

Bacterial community isolated from different units of a Drinking Water Treatment Plant (DWTP) including pre-ozonation unit (POU), the effluent-sludge mixture of the sedimentation unit (ESSU) and top-sand layer water sample from the filtration unit (TSFU) were acclimatized separately in the microcystin-leucine arginine (MC-LR)-rich environment to evaluate MC-LR biodegradation. Maximum biodegradation efficiency of 97.2 ± 8.7% was achieved by the acclimatized-TSFU bacterial community followed by 72.1 ± 6.4% and 86.2 ± 7.3% by acclimatized-POU and acclimatized-ESSU bacterial community, respectively. Likewise, the non-acclimatized bacterial community showed similar biodegradation efficiency of 71.1 ± 7.37%, 86.7 ± 3.19% and 94.35 ± 10.63% for TSFU, ESSU and POU, respectively, when compared to the acclimatized ones. However, the biodegradation rate increased 1.5-folds for acclimatized versus non-acclimatized conditions. The mass spectrometry studies on MC-LR degradation depicted hydrolytic linearization of cyclic MC-LR along with the formation of small peptide fragments including Adda molecule that is linked to the reduced toxicity (qualitative toxicity analysis). This was further confirmed quantitatively by using Rhizobium meliloti as a bioindicator. The acclimatized-TSFU bacterial community comprised of novel MC-LR degrading strains, Chryseobacterium sp. and Pseudomonas fragi as confirmed by 16S rRNA sequencing. Biodegradation of microcystin-LR by in-situ bacterial community present in the drinking water treatment plant without formation of toxic by-product.Fil: Kumar, Pratik. Université du Québec a Montreal; CanadáFil: Hegde, Krishnamoorthy. Université du Québec a Montreal; CanadáFil: Brar, Satinder Kaur. Université du Québec a Montreal; CanadáFil: Cledón, Maximiliano. Universidad Nacional del Comahue; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kermanshahi-pour, Azadeh. Dalhousie University Halifax; CanadáFil: Roy-Lachapelle, Audrey. University of Montreal; CanadáFil: Galvez-Cloutier, Rosa. Laval University; Canad

Physico-chemical treatment for the degradation of cyanotoxins with emphasis on drinking water treatment - How far have we come?

Over the years, various physicochemical treatment processes, such as photocatalysis, membrane technology, ozonolysis and chlorination have been tested at laboratory and pilot scale for the treatment of various cyanotoxins. Most of these treatment processes are also being commonly practiced in a drinking water treatment plants (DWTPs). However, the degree of treatment widely varies among cyanotoxin variants and is mainly governed by the source water characteristics, operational parameters (temperature, pH, cyanotoxin level) which changes continuously in a DWTPs. Other common elements present in raw water, such as natural organic matter (NOMs), residual nutrients and metal ions shows competitive behaviour with the cyanotoxins. Thus, a high demand in input energy is needed for unit operations, such as photocatalysis, reverse osmosis membrane and excess chemical requirement in terms of ozone, permanganate and chlorine (for ozonation and chlorination) which can breach the guidelines and increase the toxicity level. This review provides an insight into the effectiveness of major physico-chemical operations from simple to the advanced treatment level for the removal of different cyanotoxins along with their limitations and challenges in a DWTP. The goal of this review is to provide information on the possible reaction mechanism involved in the cyanotoxin treatment, accounting mainly for the toxicity, modifications in the process that happened over the years and the process feasibility. In future, hybrid technique assisted by UV, peroxides, among others promises to assist photocatalytic, ozonation and chlorination to undergo efficient cyanotoxin removal with reduced toxicity level. Also, persistence cyanotoxins, such as anatoxin and saxitoxin need further study.Fil: Kumar, Pratik. Université du Québec a Montreal; CanadáFil: Hegde, Krishnamoorthy. Université du Québec a Montreal; CanadáFil: Brar, Satinder Kaur. Université du Québec a Montreal; CanadáFil: Cledón, Maximiliano. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; ArgentinaFil: Kermanshahi Pour, Azadeh. Dalhousie University Halifax; Canad

Treatment of phenanthrene and benzene using microbial fuel cells operated continuously for possible in situ and ex situ applications

Bioelectrochemical systems could have potential for bioremediation of contaminants either in situ or ex situ. The treatment of a mixture of phenanthrene and benzene using two different tubular microbial fuel cells (MFCs) designed for either in situ and ex situ applications in aqueous systems was investigated over long operational periods (up to 155 days). For in situ deployments, simultaneous removal of the petroleum hydrocarbons (>90% in term of degradation efficiency) and bromate, used as catholyte, (up to 79%) with concomitant biogenic electricity generation (peak power density up to 6.75 mWm−2) were obtained at a hydraulic retention time (HRT) of 10 days. The tubular MFC could be operated successfully at copiotrophic (100 ppm phenanthrene, 2000 ppm benzene at HRT 30 days) and oligotrophic (phenanthrene and benzene, 50 ppb each, HRT 10 days) substrate conditions suggesting its effectiveness and robustness at extreme substrate concentrations in anoxic environments. In the MFC designed for ex situ deployments, optimum MFC performance was obtained at HRT of 30 h giving COD removal and maximum power output of approximately 77% and 6.75 mWm−2 respectively. The MFC exhibited the ability to resist organic shock loadings and could maintain stable MFC performance. Results of this study suggest the potential use of MFC technology for possible in situ/ex situ hydrocarbon-contaminated groundwater treatment or refinery effluents clean-up, even at extreme contaminant level conditions

Modification of cell surface properties of Pseudomonas alcaligenes S22 during hydrocarbon biodegradation

Biodegradation of water insoluble hydrocarbons can be significantly increased by the addition of natural surfactants one. Very promising option is the use of saponins. The obtained results indicated that in this system, after 21 days, 92% biodegradation of diesel oil could be achieved using Pseudomonas alcaligenes. No positive effect on the biodegradation process was observed using synthetic surfactant Triton X-100. The kind of carbon source influences the cell surface properties of microorganisms. Modification of the surface cell could be observed by control of the sedimentation profile. This analytical method is a new approach in microbiological analysis

Investigation into the immuno-therapeutic potential of melanocortin peptides on activated chondrocytes

Melanocortin peptides are endogenously produced peptides originating from the posttranslational processing of the pro-opiomelanocortin hormone (POMC), exerting their effect by binding to class A G-protein-coupled 7 transmembrane domain receptors, positively coupled to adenylate cyclase. To date five melanocortin receptors have been identified and termed MC1 to MC5. MC1 and MC3 have previously been proposed to exert anti-inflammatory effects by modulating the host inflammatory response. The expression and the functional activity of both receptors was identified and confirmed in the C-20/A4 chondrocyte cell-line, isolated primary bovine and in situ bovine articular chondrocytes. Pro-inflammatory cytokines including IL-1β, IL-6, IL-8, TNF-α, produced by activated articular chondrocytes significantly up-regulate matrix metalloproteinases (MMPs) gene expression, and inhibit the chondrocyte’s compensatory synthesis pathways required to restore the integrity of the degraded extracellular matrix (ECM). Human C-20/A4 and primary bovine articular chondrocytes were found to produce CC and CXC chemokines, which induced the release of matrix degrading enzymes and activated cell apoptotic pathways. TNF-α significantly up-regulated the expression of pro-inflammatory cytokines and chemokines IL-1β, IL-6, IL-8, MCP-1 and MMP1 and 13 from C-20/A4 cell line and freshly isolated primary bovine articular chondrocytes. An effect attenuated in the presence of α-MSH and D[TRP]8-γ-MSH. The MC3/4 antagonist SHU9119 blocked the effects of D[TRP]8-γ-MSH but not α-MSH. TNF-α (60.0 pg/ml) stimulation caused ~30% cell death and was partially, but significantly inhibited by treatment of the cells with the melanocortin peptides. The antiinflammatory and chondroprotective effect of melanocortin peptides were then tested on in situ bovine articular chondrocytes, injured by a single blunt impact delivered by a drop tower. The mechanical injury caused significant cell death and up-regulation of the proinflammatory cytokines IL-6 and IL-8, which were significantly reduced on pre-treatment of cartilage explants with melanocortin peptides. Modulation of pro-inflammatory pathways and inflammation-modulated cartilage destruction with subsequent chondrocyte apoptosis appears to be logical development in the potential medical therapy of OA. The small molecular weight of melanocortin peptides should facilitate the absorption from the GI tract and the movement to the cartilage matrix, which together with creative drug delivery methods might potentially prove to be potent therapeutic agents in the future

Study of Effects of Tax on Vehicle on Reducing Tehran Air Pollutants from Viewpoint of Urban Management

ABSTRACT Based on a report by The Organization for Economic Co-operation and Development (2001), approximately all environmental components are influenced by human activities. In fact, human activities cause undesirable effects on climate changes, weather and earth. The present paper aims to study effect of environmental tax on vehicle on reducing Tehran air pollutants from viewpoint of urban management. In perspective of this purpose, this paper is applicable, in terms of data collecting, this paper is descriptive. Statistical population of this paper includes people who had gone to centers of car technical examination at the last three months of 2011, sample size in accordance with statistical pollution and Morgan table has been determined 576, however, this number increased to 586 cases in this research. Moreover, Chi-square test one variable type and one way analysis of variance are tests used in this research. Findings show that individuals participating in this research -without considering their age, education, gender, social and financial class-all emphasize the role of environmental tax in reducing Tehran air pollutants. Moreover, making a proper culture and informing people about advantages of making environmental tax and its effect on reducing Tehran air pollutants have been effective as well

Towards the development of green plasticizers

Research was conducted to investigate the effect of chemical functional groups, including the ether function and alkyl branches, on the biodegradation mechanisms and biodegradation rates of dibenzoate plasticizers. Biodegradation of 1,6-hexandiol dibenzoate, a potential green dibenzoate plasticizer, by Rhodococcus rhodochrous, was investigated in the presence of hexadecane as a primary carbon source. The metabolites, produced in the biodegradation process were detected using GC/MS and Fourier transform mass spectroscopy techniques. None of these metabolites were stable, with all tending to biodegrade over the course of the experiments. Biodegradation mechanisms were elucidated for 1,6-hexanediol dibenzoate and two commercial plasticizers, diethylene glycol dibenzoate (D(EG)DB) and dipropylene glycol dibenzoate (D(PG)DB). Biodegradation of all of these plasticizers was initiated by hydrolysis of one ester bond to release a monobenzoate and benzoic acid. It was demonstrated that the diol fragment of 1,6-hexanediol monobenzoate was processed via a β-oxidation pathway, which was not possible for diethylene glycol monobenzoate (D(EG)MB) and dipropylene glycol monobenzoate (D(PG)MB) due to the presence of an ether function in the diols. Thus, accumulation of D(EG)MB and D(PG)MB was observed in the biodegradation broth. The biodegradation of commercial plasticizers, D(EG)DB and D(PG)DB and three alternative plasticizers, 1,3-propanediol dibenzoate, 2,2-methyl-propyl-1,3-propanediol dibenzoate and 1,6-hexanediol dibenzoate, were modeled using a Michaelis-Menten/Monod-type kinetic model. Biodegradation was conducted in an aerated bioreactor using resting cells of Rhodococcus rhodochrous, which had been grown with hexadecane as the primary substrate. Monobenzoates released from the biodegradation of commercial plasticizers degraded slower than the monobenzoates of alternative plasticizers. The rapid biodegradation of monobenzoates released from microbial hydrolysis of altDes recherches ont été réalisées pour étudier l'effet des groupes chimiques fonctionnels, y compris la fonction éther et les branches d'alkyle, sur les mécanismes de biodégradation et les taux de biodégradation des plastifiants dibenzoate. La biodégradation du 1,6-dibenzoate hexanediol, un plastifiant dibenzoate potentiel, par Rhodochrous rhodococcus, a été étudiée en présence d'hexadécane comme source de carbone primaire. Les métabolites, produits dans les processus de biodégradation ont été détectés par GC/MS et techniques de spectroscopie de masse à transformée de Fourier. Aucun de ces métabolites ne sont stables, tous avaient une tendance à la dégradation durant les expériences. Les mécanismes de biodégradation ont été élucidés pour le dibenzoate de 1,6-hexanediol et de deux plastifiants commerciaux, le dibenzoate de diéthylène glycol (D(EG)DB) et le dibenzoate dipropylèneglycol (D(PG)DB). La biodégradation de l'ensemble de ces plastifiants a été initié par hydrolyse d'une liaison ester pour libérer un monobenzoate et de l'acide benzoïque. Il a été démontré que le fragment de 1,6-diol monobenzoate hexanediol est généré par une β-oxydation, ce qui n'était pas possible pour le monobenzoate diéthylène glycol (D(EG)MB) et le monobenzoate dipropylèneglycol (D(PG)MB) en raison de la présence d'une fonction éther dans les diols. Ainsi, l'accumulation de D(EG)MB et D(PG)MB a été observée dans le bouillon de biodégradation. La biodégradation des plastifiants commerciaux, D(EG)DB et D(PG)DB et trois plastifiants de remplacement, le dibenzoate de 1,3-propanediol, le dibenzoate de 2,2-méthyl-propyl-1propanediol et le dibenzoate de 1,6-hexanediol, a été modélisée à l'aide d'un modèle cinétique Michaelis-Menten/Monod-type. La biodégradation a été effectuée dans un bioréacteur aéré à l'aide de cellules au repos Rhodochrous rhodococcus, qui avaient été cultivées avec l'hexadécane comme subs

Parenthood in adopted parents : Adoption as a lifelong process

Denna uppsats handlar om adoption utifrån identitet och anknytning och fokuserar på hur föräldraskap påverkas av dessa faktorer. Syftet är att undersöka hur internationellt adopterade vuxna upplever sitt föräldraskap och hur detta påverkas i förhållande till identitetsutveckling och anknytning. Tidigare forskning har visat att det inte finns endast ett sätt att uppleva adoption på, utan erfarenheter skiljs åt från individ till individ. Det har visat sig finnas ett begränsat utbud av forskning av ämnet adoption och föräldraskap och där resultatet varierat. Uppsatsen utgår ifrån en kvalitativ metod, då denna anses som mest passande för att kunna ta del av intervjupersonernas egna erfarenheter och tankar kring föräldraskap som adopterade. Materialet är insamlat genom semistrukturerade intervjuer från sex individer som blivit adopterade till Sverige och materialet har sedan analyserats utifrån en tematisk analysmetod. Resultatet visar att adoption har påverkat adopterade individers föräldraskap på så sätt att utseendemässiga likheter och att ha samma blod är av stor betydelse, samt upplever större kontrollbehov och separationssvårigheter. Det framkommer även att adopterade inte kan tänka sig att adoptera själva, vilket förklaras med att det inte anses vara enligt barnets bästa.This study explores adoption based on identity and attachment and focuses on how parenting is affected by these factors.  The purpose of this study is to investigate how transnational adopted adults experience their parenthood and how this is affected in relation to identity development and attachment. Previous research has shown that there is not only one way to experience adoption, but experiences are separated from individual to individual. There has been a limited range of research on adoption and parenting and where results have varied. The study is based on a qualitative method, as this is considered most suitable for being able to take it from the participants' own experiences and thoughts about parenthood as adopted. The material is collected through semi-structured interviews analyzed based on a thematic analysis method. The results show that adoption has affected the parenting of adopted individuals in such a way that similarities in appearance and having the same blood are of great importance, as well as experiencing a greater need for control and separation difficulties. It also appears that adoptees cannot imagine adopting themselves, which is explained by the fact that it is not considered to be in the best interests of the child.

Algal Polysaccharides-Based Hydrogels: Extraction, Synthesis, Characterization, and Applications

Hydrogels are three-dimensional crosslinked hydrophilic polymer networks with great potential in drug delivery, tissue engineering, wound dressing, agrochemicals application, food packaging, and cosmetics. However, conventional synthetic polymer hydrogels may be hazardous and have poor biocompatibility and biodegradability. Algal polysaccharides are abundant natural products with biocompatible and biodegradable properties. Polysaccharides and their derivatives also possess unique features such as physicochemical properties, hydrophilicity, mechanical strength, and tunable functionality. As such, algal polysaccharides have been widely exploited as building blocks in the fabrication of polysaccharide-based hydrogels through physical and/or chemical crosslinking. In this review, we discuss the extraction and characterization of polysaccharides derived from algae. This review focuses on recent advances in synthesis and applications of algal polysaccharides-based hydrogels. Additionally, we discuss the techno-economic analyses of chitosan and acrylic acid-based hydrogels, drawing attention to the importance of such analyses for hydrogels. Finally, the future prospects of algal polysaccharides-based hydrogels are outlined