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

Green synthesis of novel biocomposites from treated cellulosic fibers and recycled bio-plastic polylactic acid

This study investigated mechanical properties of biocomposites developed from recycled polylactic acid (PLA) from packaging industry and treated cellulosic fibers from pulp and paper solid waste. Microwave and enzymatic treatments were used for extraction and surface modification of hydrophilic cellulosic fibers. Enzymatic treatment was specifically performed for activation of hydroxyl groups and improvement of adhesion between matrix and fibers including controlling the length of cellulosic fibers with size reduction of around 50% (142 and 127 mm for primary and mixed biosolids, respectively) as compared to microwave treatment. Microwave treatment produced cellulosic fibers of 293 and 341 mm, for primary and mixed biosolids, respectively. Mechanical properties of biocomposites with 2% (w/w) of treated cellulosic fibers (Young's Modulus 887.83 MPa with tensile strain at breakpoint of 7.22%, tensile stress at yield 41.35 MPa) was enhanced in comparison to the recycled PLA (Young's Modulus 644.47 ± 30.086 MPa with tensile strain at breakpoint of 6.01 ± 0.83%, tensile stress at yield of 29.49 ± 3.64 MPa). Scanning electron microscopy revealed size reduction of cellulosic fibers. X-ray diffraction and Fourier transform infrared spectroscopy confirmed strong mechanical properties of novel biocomposites.The authors are sincerely thankful to the Natural Sciences and Engineering Research Council of Canada (Discovery Grant 355254 and NSERC CRD Grant), and CRIBIQ for financial support. We would like to thank Mr. R. Fortin and Colin Jacob Vaillancourt from Gaudreau Environment for providing rPLA samples. Likewise, the support of Ozymes Inc. is equally appreciated for valuable comments during the experimental planning from industrial perspective. Financial assistance by the ‘Fonds de recherche du Quebec- Nature et technologies (FRQNT)’ and INRS-ETE has been thankfully acknowledged by K Hegde.info:eu-repo/semantics/publishedVersio

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Potential of biological approaches for cyanotoxin removal from drinking water: A review

Biological treatment of cyanotoxins has gained much importance in recent decades and holds a promise to work in coordination with various physicochemical treatments. In drinking water treatment plants (DWTPs), effective removal of cyanotoxins with reduced toxicity is a primary concern. Commonly used treatments, such as ozonation, chlorination or activated carbon, undergo significant changes in their operating conditions (mainly dosage) to counter the variation in different environmental parameters, such as pH, temperature, and high cyanotoxin concentration. Presence of metal ions, natural organic matter (NOM), and other chemicals demand higher dosage and hence affect the activation energy to efficiently break down the cyanotoxin molecule. Due to these higher dose requirements, the treatment leads to the formation of toxic metabolites at a concentration high enough to break the guideline values. Biological methods of cyanotoxin removal proceed via enzymatic pathway where the protein-encoding genes are often responsible for the compound breakdown into non-toxic metabolites. However, in contrast to the chemical treatment, the biological processes advance at a much slower kinetic rate, predominantly due to a longer onset period (high lag phase). In fact, more than 90% of the studies reported on the biological degradation of the cyanotoxins attribute the biodegradation to the bacterial suspension. This suspended growth limits the mass transfer kinetics due to the presence of metal ions, NOMs and, other oxidizable matter, which further prolongs the lag phase and makes biological process toxic-free, albeit less efficient. In this context, this review attempts to bring out the importance of the attached growth mechanism, in particular, the biofilm-based treatment approaches which can enhance the biodegradation rate.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; Canadá. University of York; Reino UnidoFil: 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

Crabtree Effect on <i>Rhodosporidium toruloides</i> Using Wood Hydrolysate as a Culture Media

The interest in microorganisms to produce microbial lipids at large-scale processes has increased during the last decades. Rhodosporidium toruloides-1588 could be an efficient option for its ability to simultaneously utilize five- and six-carbon sugars. Nevertheless, one of the most important characteristics that any strain needs to be considered or used at an industrial scale is its capacity to grow in substrates with high sugar concentrations. In this study, the effect of high sugar concentrations and the effect of ammonium sulfate were tested on R. toruloides-1588 and its capacity to grow and accumulate lipids using undetoxified wood hydrolysates. Batch fermentations showed a catabolic repression effect on R. toruloides-1588 growth at sugar concentrations of 120 g/L. The maximum lipid accumulation was 8.2 g/L with palmitic, stearic, oleic, linoleic, and lignoceric acids as predominant fatty acids in the produced lipids. Furthermore, R. toruloides-1588 was able to utilize up to 80% of the total xylose content. Additionally, this study is the first to report the effect of using high xylose concentrations on the growth, sugar utilization, and lipid accumulation by R. toruloides-1588

Characteristics of aerosol black carbon mass concentration over a high altitude location in the central Himalayas from multi-year measurements

Multi-year measurements of near surface aerosol black carbon (BC) mass concentration, made from a high altitude station at Manora Peak (29.4&#176; N, 79.5&#176; E, 1958 m msl) in the Central Himalayas, using a 7-channel Aethalometer for 38 months from November 2004 to December 2007, are examined. Temporally, BC exhibited well-defined diurnal variations, comprising of a single prominent peak occurring in the late afternoon (before sunset) hours during the months from October to March, while these variations were insignificant during April to September. These were found to be closely associated with the dynamics of atmospheric boundary layer (ABL), and pose a form that is distinctly different from those reported for the plains. BC mass concentrations were always higher by a factor of about 2 during daytime than the concentrations during nighttime. Seasonally, BC mass concentrations were higher during spring (with a mean value of 1.34 &#177; 0.05 &#956;g m-3), which are attributed to lifting up of pollutants from the valley (below the mountain peak) by the convective boundary layer and increased local emissions. The concentration decreased by a factor of 2 in summer (0.53 &#177; 0.02) and recovered during autumn (1.03 &#177; 0.04). The long-term average value was 0.99 &#177; 0.02 &#956;g m-3. Examination of the wavelength dependence revealed that BC observed at this location is generally dominated by fossil fuel combustion

Novel fluidized-bed biofilm reactor for concomitant removal of microcystin-LR and organics

Fluidized bed biofilm reactor (FBBR) was evaluated for the removal of microcystin-LR (MC-LR) from drinking water-sludge (0.3% w/v). Biofilm formed inside the solid media carriers (biocarriers) were studied for the MC-LR degradation in FBBRs via known MC-LR degraders: Arthrobacter ramosus (reactor A: RA) and Bacillus sp. (reactor B: RB), along with the heterogeneous bacterial community (HBC) present in the sedimentation-unit sludge as a background matrix. Their ability to form biofilm inside the immobilized biocarriers was periodically quantified for over 300 days to determine the duration of mature biofilm growth, sloughing event and then re-maturation. The bioreactor performance was mainly evaluated in terms of MC-LR, nitrate, nitrite, ammonia removal, and soluble-chemical oxygen demand (s-COD) removal. Biological degradation of MC-LR showed significant role over the physical adsorption, as the removal efficiency increased by around 30% and 26% for RA and RB respectively, as compared to the control bioreactor RD (without any bacterial cells) and an increase by over 15% and 11% when compared to reactor RC (contained only HBC). Mass spectra analysis for RA, RB, and RC strengthen the possibility of a toxic-free degradation mechanism. Overall, RA showed the best MC-LR removal efficiency of around 93.7%, which comprised no MC-LR in the supernatant phase and around 3 µg/L in the sludge-mixture phase. Toxicity assessment of biodegraded sample (using bioindicator) further revealed the toxic-free nature by RA with >80% removal for ammonia, nitrate, and nitrite. Scale-up of laboratory scale FBBR (2 L) is also proposed to handle 200 m3 of feed water per day based on a similar volumetric mass transfer coefficient (kLa) to study the feasible process economics.Fil: Kumar, Pratik. Centre Eau Terre Environnement; CanadáFil: Hegde, Krishnamoorthy. Centre Eau Terre Environnement; CanadáFil: Brar, Satinder Kaur. Centre Eau Terre Environnement; 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; CanadáFil: Roy Lachapelle, Audrey. University of Montreal; Canadá. Environment Canada; CanadáFil: Galvez Cloutier, Rosa. Laval University; Canad

Co-culturing of native bacteria from drinking water treatment plant with known degraders to accelerate microcystin-LR removal using biofilter

The biofilm-mediated bioremediation of drinking water source for Microcystin-LR degradation under various water quality parameters was investigated using sand filter with known Microcystin (MC)-degrading bacterial genera: Arthrobacter (A), Bacillus (B) and Sphingomonas (S), both under individual (A, B and S) as well as co-culture condition (A + X, B + X and S + X) with the native bacterial strains (Pseudomonas fragi and Chryseobacterium sp. = X). These native bacterial strains were isolated from the filtration unit of a drinking water treatment plant (DWTP). Before starting the filter operation, the biofilm-forming ability of MC-degraders was evaluated using a unique experimental set-up. The study showed that the MC-LR removal was enhanced by 38% using S + X filter as compared to the uninoculated filter (control). Except for Bacillus sp., MC-degraders in the form of Arthrobacter ramosus and Sphingomonas sp. enhanced the MC removal potential of the native bacterial strains (X) by 10% and 17%, respectively. The central composite design was used to obtain an optimized input parameter (pH, temperature, initial turbidity and retention time) for the filter operation. Various output parameters including dissolved organic carbon (DOC), total coliform, turbidity, dissolved oxygen, MC-LR toxicity and ammonia were analyzed to form a well-generalized model with a desirability index of 0.638. Overall, filter S + X achieved a non-detectable MCs concentration in some cycles and showed an average of >30% DOC and >80% of total coliform removal along with an under-regulated removal of nitrite, nitrate and ammonia. However, MC-LR breakthrough occurred after 8 weeks of filter operation. These studies demonstrated the effectiveness of inoculating MC-degraders in an existing filtration unit of a DWTP to remove the seasonal occurrence of MCs in the water source.Fil: Kumar, Pratik. Université du Québec; CanadáFil: Hegde, Krishnamoorthy. Université du Québec; CanadáFil: Brar, Satinder Kaur. Université du Québec; Canadá. York University; 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; CanadáFil: Roy-Lachapelle, Audrey. University of Montreal; Canadá. Environment and Climate Change Canada; CanadáFil: Sauvé, Sébastien. University of Montreal; CanadáFil: Galvez-Cloutier, Rosa. Laval University; Canad