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Journal of Microbiology and... Jul 2023Disposal of waste containing heavy metals into the environment is a major threat to human health and can result in toxic or chronic poisoning in aquatic life. In the...
Disposal of waste containing heavy metals into the environment is a major threat to human health and can result in toxic or chronic poisoning in aquatic life. In the current study, metal-resistant was isolated from metal-contaminated samples collected from the Tanjaro River, located southwest of Sulaymaniyah, Iraq. was identified by partial amplification of 16S rRNA. The uptake potency of heavy metals was assessed using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and indicated that removed 67, 89, 63.4, 55.6, 56.5, 65, and 61.9% of Cd, Pb, Cr, Ni, Zn, Co, and Fe, respectively. These removal rates were influenced by temperature, pH, and contact time; at 35°C and pH 5 with a change in the incubation time, the reduction rate improved from 89 to 95% for Pb, from 36.4 to 45% for Cu, and from 55.6 to 64% for Ni. Gene analysis indicated that contained , , , , and genes, but the gene was absent. Energy-dispersive X-ray spectroscopy (EDS) images showed evidence of metal ion binding on the cell wall surface with different rates of binding. Transmission electron microscopy (TEM) detected different mechanisms for metal particle localization; cell surface adsorption was the main mechanism for Pb, Zn, and Co uptake, while Cd, Ni, and Fe were accumulated inside the cell. The current study describes, for the first time, the isolation of from metal-contaminated water, which can be used as an eco-friendly biological expedient for the remediation and detoxification of metals from contaminated environments.
Topics: Humans; Cadmium; Biodegradation, Environmental; RNA, Ribosomal, 16S; Lead; Metals, Heavy; Environmental Monitoring
PubMed: 37164756
DOI: 10.4014/jmb.2212.12045 -
The Science of the Total Environment Aug 2023Here we report the detection of carbapenemase-producing Enterobacterales (CPE) isolated from Swedish wastewater and gull faeces. CPE have not been detected in samples...
Here we report the detection of carbapenemase-producing Enterobacterales (CPE) isolated from Swedish wastewater and gull faeces. CPE have not been detected in samples from animals in Sweden preceding this report. Sampling of wastewater treatment plant (WWTP) inlet and outlet, sedimentation basins, surface seawater from key aquatic bird habitats and freshly deposited gull faeces was done on six separate occasions during May to September 2021. Following broth enrichment, selective screening of putative CPE was performed on mSuperCarba™ (CHROMagar). Species identification was done with MALDI-TOF. Antimicrobial susceptibility testing was performed according to EUCAST. In total, seventeen CPE were verified by genome sequencing carrying bla, bla, bla or bla. The bla was carried on IncP plasmids in four different species; Escherichia coli ST10 isolated from WWTP outlet, Raoultella ornithinolytica isolated from WWTP inlet, outlet and sedimentation basins as well as gull faeces collected at the WWTP and Klebsiella spp. isolates from WWTP inlet and outlet. The genetic environment surrounding bla was similar in two Citrobacter freundii causing human infections. The bla was carried on IncFII(Yp) plasmids in four Enterobacter ludwigii, isolated from WWTP outlet and gull faeces collected at a recreational city park 2 km from the WWTP. The bla was located on a COLKP3 plasmid found in an E. coli, while bla was chromosomally located in an E. coli ST10, both isolated from WWTP inlet. Phylogenetic analysis of R. ornithinolytica and E. ludwigii isolates indicate that the gulls carried strains related to those identified in the WWTP samples. The results thus add to the increasing evidence of WWTPs as anthropogenic reservoirs for mobile genetic elements with antibiotic-resistance functionality. Such environments could profoundly impact the dissemination and spread of such genetic elements via for example aquatic birds, thereby warranting further study and surveillance.
Topics: Animals; Humans; Wastewater; Charadriiformes; Sweden; Escherichia coli; Phylogeny; Bacterial Proteins; beta-Lactamases; Plasmids; Water Purification; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37164093
DOI: 10.1016/j.scitotenv.2023.163997 -
Biofilm Dec 2023Many companies in the food industry apply reverse osmosis (RO) membranes to ensure high-quality reuse of water. Biofouling is however, a common, recalcitrant and...
Many companies in the food industry apply reverse osmosis (RO) membranes to ensure high-quality reuse of water. Biofouling is however, a common, recalcitrant and recurring problem that blocks transport over membranes and decreases the water recovery. Microorganisms adhering to membranes may form biofilm and produce an extracellular matrix, which protects against external stress and ensures continuous attachment. Thus, various agents are tested for their ability to degrade and disperse biofilms. Here, we identified industrially relevant bacterial model communities that form biofilms on RO membranes used for treating process water before reuse. There was a marked difference in the biofilm forming capabilities of bacteria isolated from contaminated RO membranes. One species, , was particularly capable of forming biofilm and was included in most communities. The potential of different enzymes (Trypsin-EDTA, Proteinase K, α-Amylase, β-Mannosidase and Alginate lyase) as biofouling dispersing agents was evaluated at different concentrations (0.05 U/ml and 1.28 U/ml). Among the tested enzymes, β-Mannosidase was the only enzyme able to reduce biofilm formation significantly within 4 h of exposure at 25 °C (0.284 log reduction), and only at the high concentration. Longer exposure duration, however, resulted in significant biofilm reduction by all enzymes tested (0.459-0.717 log reduction) at both low and high concentrations. Using confocal laser scanning microscopy, we quantified the biovolume on RO membranes after treatment with two different enzyme mixtures. The application of proteinase K and β-Mannosidase significantly reduced the amount of attached biomass (43% reduction), and the combination of all five enzymes showed even stronger reducing effect (71% reduction). Overall, this study demonstrates a potential treatment strategy, using matrix-degrading enzymes for biofouled RO membranes in food processing water treatment streams. Future studies on optimization of buffer systems, temperature and other factors could facilitate cleaning operations based on enzymatic treatment extending the lifespan of membranes with a continuous flux.
PubMed: 37131492
DOI: 10.1016/j.bioflm.2023.100119 -
The Science of the Total Environment Aug 2023Anthropogenic activities have increased the dispersal of emerging contaminants (ECs), particularly of parabens, causing an escalation of their presence in wastewater...
Anthropogenic activities have increased the dispersal of emerging contaminants (ECs), particularly of parabens, causing an escalation of their presence in wastewater (WW). Current WW technologies do not present satisfactory efficiency or sustainability in removing these contaminants. However, bioremediation with microalgae-based systems is proving to be a relevant technology for WW polishing, and the use of microalgae-bacteria consortia can improve the efficiency of WW treatment. This work aimed to study dual cultures of selected bacteria (Raoultella ornithinolytica, Acidovorax facilis, Acinetobacter calcoaceticus, Leucobacter sp. or Rhodococcus fascians) and the microalga Chlorella vulgaris in microbial growth and WW bioremediation - removal of methylparaben (MetP) and nutrients. The association with the bacteria was antagonistic for C. vulgaris biomass productivity as a result of the decreased growth kinetics in comparison to the axenic microalga. The presence of MetP did not disturb the growth of C. vulgaris under axenic or co-cultured conditions, except when associated with R. fascians, where growth enhancement was observed. The removal of MetP by the microalga was modest (circa 30 %, with a removal rate of 0.0343 mg/L.d), but increased remarkably when the consortia were used (> 50 %, with an average removal rate > 0.0779 mg/L.d), through biodegradation and photodegradation. For nutrient removal, the consortia were found to be less effective than the axenic microalga, except for nitrogen (N) removal by C. vulgaris w/ R. fascians. The overall results propose that C. vulgaris co-cultivation with bacteria can increase MetP removal, while negatively affecting the microalga growth and the consequent reduction of sludge production, highlighting the potential of microalgae-bacteria consortia for the effective polishing of WW contaminated with parabens.
Topics: Chlorella vulgaris; Wastewater; Coculture Techniques; Parabens; Bacteria; Microalgae
PubMed: 37121314
DOI: 10.1016/j.scitotenv.2023.163746