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With widespread occurrence and increasing concern of emerging contaminants (CECs) in source water, biologically active filters (BAF) have been gaining acceptance in water treatment. Both BAFs and graphene oxide (GO) have been shown to be effective in treating CECs. However, studies to date have not addressed interactions between GO and microbial communities in water treatment processes such as BAFs. Therefore, in the present study, we investigated the effect of GO on the properties and microbial growth rate in a BAF system. Synthesized GO was characterized with a number of tools, including scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectrometry. GO exhibited the characteristic surface functional groups (i.e., C-OH, C=O, C-O-C, and COOH), crystalline structure, and sheet-like morphology. To address the potential toxicity of GO on the microbial community, reactive oxygen species (ROS) generation was measured using nitro blue tetrazolium (NBT) assay. Results revealed that during the exponential growth phase, ROS generation was not observed in the presence of GO compared to the control batch. In fact, the adenosine triphosphate (ATP) concentrations increased in the presence of GO (25 μg/L - 1000 μg/L) compared to the control without GO. The growth rate in systems with GO exceeded the control by 20 % to 46 %. SEM images showed that GO sheets can form an effective scaffold to promote bacterial adhesion, proliferation, and biofilm formation, demonstrating its biocompatibility. Next-generation sequencing (Illumina MiSeq) was used to characterize the BAF microbial community, and high-throughput sequencing analysis confirmed the greater richness and more diverse microbial communities compared to systems without GO. This study is the first to report the effect of GO on the microbial community of BAF from a water treatment plant, which provides new insights into the potential of utilizing a bio-optimized BAF for advanced and sustainable water treatment or reuse strategies. 

Recalcitrance in microplastics accounts for ubiquitous white pollution. Of special interest are the capabilities of microorganisms to accelerate their degradation sustainably. Compared to the well-studied pure cultures in degrading natural polymers, the algal-bacterial symbiotic system is considered as a promising candidate for microplastics removal, cascading bottom-up impacts on ecosystem-scale processes. This study selected and enriched the algae-associated microbial communities hosted by the indigenous isolation Desmodesmus sp. in wastewater treatment plants with micro-polyvinyl chloride, polyethylene terephthalate, polyethylene, and polystyrene contamination. Results elaborated that multiple settled and specific affiliates were recruited by the uniform algae protagonist from the biosphere under manifold microplastic stress. Alteration of distinct chemical functionalities and deformation of polymers provide direct evidence of degradation in phycosphere under illumination. Microplastic-induced phycosphere-derived DOM created spatial gradients of aromatic protein, fulvic and humic acid-like and tryptophan components to expanded niche-width. Surface thermodynamic analysis was conducted to simulate the reciprocal and reversible interaction on algal-bacterial and phycosphere-microplastic interface, revealing the enhancement of transition to stable and irreversible aggregation for functional microbiota colonization and microplastics capture. Furthermore, pangenomic analysis disclosed the genes related to the chemotaxis and the proposed microplastics biodegradation pathway in enriched algal-bacterial microbiome, orchestrating the evidence for common synthetic polymer particles and ultimately to confirm the effectiveness and potential. The present study emphasizes the necessity for future endeavors aimed at fully leveraging the potential of algal-bacterial mutualistic systems within sustainable bioremediation strategies targeting the eradication of microplastic waste. 

Fluorotelomer carboxylic acids (FTCAs) represent an important group of per- and polyfluoroalkyl substances (PFAS) given their high toxicity, bioaccumulation potential, and frequent detection in landfill leachates and PFAS-impacted sites. In this study, we assessed the biodegradability of 6:2 FTCA and 5:3 FTCA by activated sludges from four municipal wastewater treatment plants (WWTPs) in the New York Metropolitan area. Coupling with 6:2 FTCA removal, significant fluoride release (0.56∼1.83 F-/molecule) was evident in sludge treatments during 7 days of incubation. Less-fluorinated transformation products (TPs) were formed, including 6:2 fluorotelomer unsaturated carboxylic acid (6:2 FTUCA), perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), and perfluorobutanoic acid (PFBA). In contrast, little fluoride (0.01∼0.09 F-/molecule) was detected in 5:3 FTCA-dosed microcosms, though 25∼68% of initially dosed 5:3 FTCA was biologically removed. This implies the dominance of “non-fluoride-releasing pathways” that may contribute to the formation of CoA adducts or other conjugates over 5:3 FTCA biotransformation. The discovery of defluorinated 5:3 FTUCA revealed the possibility of microbial attacks of the C-F bond at the γ carbon to initiate the transformation. Microbial community analysis revealed the possible involvement of 9 genera, such as Hyphomicrobium and Dechloromonas, in aerobic FTCA biotransformation. This study unraveled that biotransformation pathways of 6:2 and 5:3 FTCAs can be divergent, resulting in biodefluorination at distinctive degrees. Further research is underscored to uncover the nontarget TPs and investigate the involved biotransformation and biodefluorination mechanisms and molecular basis. 

Biofiltration systems would harbor and spread various antibiotic resistance genes (ARGs) when treating antibiotic micro-pollution, constituting a potential ecological risk. This study aimed to investigate the effects of biochar pores on ARG emergence and related microbial response mechanisms in bench-scale biofiltration systems. Results showed that biochar pores effectively reduced the absolute copies of the corresponding ARGs sul1 and sul2 by 54.1% by lowering the sorbed-SMX's bioavailability compared to non-porous anthracite. An investigation of antimicrobial resistomes revealed a considerable decrease in the abundance and diversity of ARGs and mobile gene elements. Metagenomic and metaproteomic analysis demonstrated that biochar pores induced the changeover of microbial defense strategy against SMX from blocking SMX uptake by EPS absorbing to SMX biotransformation. Microbial SOS response, antibiotic efflux pump, EPS secretion, and biofilm formation were decreased. Functions related to SMX biotransformation, such as sadABC-mediated transformation, xenobiotics degradation, and metabolism, were significantly promoted. 

Abstract Chryseobacteriaconsists of important human pathogens that can cause a myriad of nosocomial infections. We isolated four multidrug‐resistantChryseobacteriumbacteria from activated sludge collected at domestic wastewater treatment facilities in the New York Metropolitan area. Their genomes were sequenced with Nanopore technology and used for a comprehensive resistomics comparison with 211Chryseobacteriumgenomes available in the public databases. A majority ofChryseobacteriaharbor 3 or more antibiotic resistance genes (ARGs) with the potential to confer resistance to at least two types of commonly prescribed antimicrobials. The most abundant ARGs, including β‐lactam class A (blaCGA‐1andblaCIA) and class B (blaCGB‐1andblaIND) and aminoglycoside (ranAandranB), are considered potentially intrinsic inChryseobacteria. Notably, we reported a new resistance cluster consisting of a chloramphenicol acetyltransferase genecatB11, a tetracycline resistance genetetX, and two mobile genetic elements (MGEs),IS91family transposase andXerDrecombinase. BothcatB11andtetXare statistically enriched in clinical isolates as compared to those with environmental origins. In addition, two other ARGs encoding aminoglycoside adenylyltransferase (aadS) and the small multidrug resistance pump (abeS), respectively, are found co‐located with MGEs encoding recombinases (e.g.,RecAandXerD) or transposases, suggesting their high transmissibility amongChryseobacteriaand across theBacteroidotaphylum, particularly those with high pathogenicity. High resistance to different classes of β‐lactam, as well as other commonly used antimicrobials (i.e., kanamycin, gentamicin, and chloramphenicol), was confirmed and assessed using our isolates to determine their minimum inhibitory concentrations. Collectively, though the majority of ARGs inChryseobacteriaare intrinsic, the discovery of a new resistance cluster and the co‐existence of several ARGs and MGEs corroborate interspecies and intergenera transfer, which may accelerate their dissemination in clinical environments and complicate efforts to combat bacterial infections. 

Cometabolic bioremediation is trending for the treatment of 1,4-dioxane (dioxane) and other emerging contaminants to meet stringent regulatory goals ( e.g. , <10 μg L −1 ) since biodegradation activities can be fueled by the supplementation of auxiliary substrates. In this study, we compared and investigated the effectiveness of two types of common auxiliary substrates, short-chain alkane gases ( e.g. , propane and butane) and primary alcohols ( e.g. , 1-propanol, 1-butanol, and ethanol), for dioxane removal in diverse environmental matrices with Azoarcus sp. DD4 as the inoculum. Physicochemical characterization at the pure culture level revealed that propane and 1-propanol are advantageous for stimulating cell growth and dioxane biodegradation by DD4. Parallel microcosm assays were conducted to assess the compatibility of DD4 bioaugmentation in diverse microbiomes recovered from five different environmental samples, including shallow and deep aquifer groundwater, contaminated river sediment, and municipal activated sludge. Propane was effective in sustaining efficient dioxane removal and the dominance of DD4 across all environmental matrices. Notably, amendment with 1-propanol promoted superior dioxane degradation in the deep aquifer groundwater, in which low pre-treatment biomass and post-treatment diversity were observed, suggesting its potential for intrinsic field applications. The combination of microbial community analysis and differential ranking identified that Ochrobactrum and several other indigenous bacteria were boosted by the inoculation of DD4, implying their commensal or mutualistic relationship. Collectively, propane and 1-propanol can be effective auxiliary substrate alternatives tailored for in situ bioaugmentation and their effectiveness is affected by the density and structure of environmental microbiomes.