Microbes In Wastewater Research Articles

Tailoring of magnetite nanocomposite of carboxymethyl chitosan impregnated with iron (III) oxide for enhanced degradation of reactive blue 19 dye and inactivation of harmful microbes in wastewater

The study investigates the fabrication of an innovative nanocomposite composed of carboxymethyl chitosan (CMCs) combined with different amounts of iron (III) oxide (Fe₂O₃) to boost dye degradation and antibacterial effectiveness. A top-down ball milling technique formed the nanocomposites and was extensively investigated for their structural, morphological, and functional features. The mean particle size of the 0.3Fe₂O₃/CMCs and 0.6Fe₂O₃/CMCs nanocomposites was 83.74 nm and 124.5 nm, respectively, with small polydispersity index (PdI) values suggesting satisfactory homogeneity. The adsorption effectiveness of Reactive Blue 19 (RB 19) dye was evaluated under different circumstances, with the 0.6Fe₂O₃/CMCs nanocomposite exhibiting the maximum adsorption capacity of 140 mg/g at an ideal pH of 5. Kinetic analyses indicated that the adsorption process adhered to a pseudo-second-order kinetic model. The nanocomposites had significant bactericidal performance, with the 0.6Fe₂O₃/CMCs nanocomposite exhibiting the most extensive inhibition zones, particularly against E. coli (28.4 mm) and Pseudomonas aeruginosa (23.2 mm). Furthermore, the reusability of the 0.6Fe₂O₃/CMCs nanocomposite was validated by five adsorption-desorption cycles, retaining over 90 % efficiency. The results underscore the efficacy of Fe₂O₃/CMCs nanocomposites as viable materials for wastewater treatment and antibacterial purposes, offering a promising approach for environmental remediation.

Performance evaluation of species varied fixed bed biofilm reactor for wastewater treatment of Dhobi Khola outfall, Setopul, Kathmandu, Nepal

The sustainability of wastewater treatment plants poses significant challenges for developing countries, necessitating substantial investment for operation and maintenance. Biofilm reactors seeded with specific species of microorganisms were investigated under controlled environmental conditions. However, the performance evaluation of such reactors under natural conditions remains largely underexplored. This study investigated wastewater treatment capabilities of bench-scale fixed bed biofilm reactors, employing various species (Wastewater Microbes, Pseudomonas, Algae, and a co-culture of Algae and Pseudomonas). The reactors (Treatments and Control) were filled with 28 mm nominal-size local aggregates as packing media, operated under different contact times, and subjected to varying concentrations of heavy metals (Zn, Cd). To assess the reactor performances, the Bland-Altman Plot and Chemical Oxygen Demand (COD) removal kinetics were evaluated.The results revealed that the reactor initiated with a co-culture exhibited the optimal COD removal efficiency, reaching 84 ± 1 %. The reactor initially seeded with wastewater microbes exhibited the highest heavy metal elimination, achieving 94 ± 1 % and 88 ± 1 % removal for Zn and Cd respectively. The wastewater-seeded reactor demonstrated the zero-order COD removal kinetic coefficient (k) of 46.41 mg/L/h at an average influent COD concentration of 558 mg/L at 10 h contact time. While Pseudomonas-seeded reactor demonstrated k = 0.73 mg/L/h at 20 h contact time with 69 mg/L influent COD and heavy metal concentrations Zn = 26 mg/L and Cd = 3.57 mg/L.The findings of this study suggest that variations in environmental conditions, contact time, and heavy metal concentration have minimal impact on the pollutant removal efficacy of the reactors, and provide robust evidence for their viability as a sustainable alternative in municipal wastewater treatment. The study also identifies the possibility of treating specific wastewater characteristics by altering the dominant species in the reactors, paving the way for further research on the efficacy of other microbial genomes in fixed bed biofilm reactors.

Associations between wastewater gut microbiome and community obesity rates: Potential microbial biomarkers for surveillance

Gut microbes are crucial for human health, which are usually accumulated in urban wastewater systems. Seven wastewater treatment plants in Australia with distinct population obesity rates between 18% and 33% were selected for wastewater sampling and analysis. Human gut microbiome were detected using metagenomic sequencing to investigate their associations with the community obesity rate. To unravel this complex relationship, a range of algorithm models, including linear discriminant analysis effect size (LEfSe), similarity percentage analysis (SIMPER), statistical analysis of metagenomic profiles (STAMP), linear models for microarray and RNA-Seq data analysis (LIMMA), Relief, ratio approach for identifying differential abundance (RAIDA), least absolute shrinkage and selection operator (LASSO), support vector machine (SVM), Boruta, DESeq2 and analysis of compositions of microbiomes with bias correction (ANCOM-BC), were used to identify potential bacterial biomarkers for obesity in the wastewater microbiome. Among these algorithm models, LEfSe, LIMMA, SIMPER and SVM are effective in identifying multiple microbial biomarkers. Specific human gut microbes, including Ruminococcus_E, Agathobacter, Fusicatenibacter, Anaerobutyricum, Blautia_A and Neisseria, were identified as potential consensus microbial biomarkers for obesity in the population. A high obesity rate is mainly characterized by a high abundance of pathogenic bacteria and microorganisms associated with xenobiotic biodegradation and metabolism, endocrine and metabolic diseases, and transcription pathways. This study underscores the innovative potential of leveraging human gut microbes in wastewater as biomarkers for monitoring obesity levels across communities, offering a novel, cost-effective, and indirect approach to public health surveillance.

Graphene oxide quantum dots membrane: a hybrid filtration-advanced technology system to enhance process of wastewater reclamation

The inability of wastewater treatment plants to effectively remove emerging pollutants has necessitated the need to develop newer advanced technologies. An integrated approach of combining advanced oxidation processes (AOPs) and membrane technologies promises superior performances. In this study, graphene oxide quantum dots-based membranes (GQDs-Ms) were fabricated via the phase inversion method. The GQDs-Ms revealed high oxygen content and a negative surface charge. The incorporating graphene oxide quantum dots (GQDs) into the polymer matrix led to enhanced hydrophilicity, pore size, porosity, improved flux as well as superior inhibition of Escherichia coli cells. A multi-AOPs approach was used in this work, wherein AOPs were applied as both pre-treatment (using GQDs) and post-treatment (combining GQDs with peracetic acid) in the disinfection of wastewater. The evaluation of GQDs-Ms performance was carried out and compared with a commercial membrane (Film Tec™NF270). The obtained % removals with GQDs-Ms were 83.45%, 64.12%, 40.76% and 70.36% for turbidity, total dissolved solids, total organic carbon and electrical conductivity, respectively, which compared nearly with commercial membrane’s performance. Interestingly, the integrated hybrid system can further remove and inactivate microbes in wastewater. The developed hybrid filtration-advanced technology system can substantially improve conventional wastewater treatment plants for water reuse.

Construction of hexagonal spindle-shaped Fe-MOFs induced by cationic copolymer and its application for effective wastewater treatment.

The environment and human health are in danger due to the long-term enrichment and buildup of organic pesticides, dyes, and harmful microbes in wastewater. The development of functional materials that are efficient for treating wastewater remains a significant problem. Eco-friendly hexagonal spindle-shaped Fe-MOFs (Hs-FeMOFs) were created in this study under the influence of cationic copolymer (PMSt). The mechanism of crystal growth and development of its unique morphology were described after looking into impact factors for the ideal circumstances and being characterized by XRD, TEM, XPS, and other techniques. It revealed that Hs-FeMOFs possess an enormous supply of adsorption active sites, a strong electropositivity, and the nanometer tip. Then, typical organic pollutants, such as herbicides and mixed dyes, as well as biological pollutants bacteria, were chosen to assess its efficacy in wastewater treatment. It was discovered that the pendimethalin could be quickly removed in wastewater and the removal rate reached 100% within 10min. In separation of mixed dyes, the retention rate of malachite green (MG) reached 92.3% in 5min and with a minimum inhibitory concentration of 0.8mg/mL and demonstrated strong activity due to the presence of cationic copolymers. In actual water matrix, Hs-FeMOF could also play excellent adsorption and antibacterial activity. In summary, a novel, environmentally friendly MOF material with good activity was successfully created by cationic copolymer induction. It offers a fresh approach to develop functional materials in wastewater treatment.

Porphyrins developed for photoinactivation of microbes in wastewater

Photodynamic antimicrobial chemotherapy (PACT) is extensively studied as a strategic method to inactivate pathogenic microbes in wastewater for addressing the limitations associated with chlorination, ozonation, and ultraviolet irradiation as disinfection methods, which generally promote the development of resistant genes and harmful by-products such as trihalomethanes. PACT is dependent on photons, oxygen, and a photosensitizer to induce cytotoxic effects on various microbes by generating reactive oxygen species. Photosensitizers such as porphyrins have demonstrated significant microbial inactivation through PACT, hence now explored for wastewater phototreatment. This review aims to evaluate the efficacy of porphyrins and porphyrin-conjugates as photosensitizers for wastewater photoinactivation. Concerns relating to the application of photosensitizers in water treatment are also evaluated. This includes recovery and reuse of the photosensitizer when immobilized on solid supports.

Sono-photocatalytic disinfection of high strength multi-drug resistant Klebsiella pneumonia in presence of blue LED-active CdS nanorods

The prevalence of antibiotic resistant pathogenic microbes in wastewater necessitates effective disinfection treatment to protect human health and the environment. Klebsiella pneumoniae is considered as an opportunistic and emerging human pathogen which can develop resistance towards a broad range of antibiotics. In the present study, a hybrid approach merging photocatalysis by CdS nanorods (NRs) with physico-chemical method of acoustic cavitation was investigated to disinfect MDR Klebsiella pneumonia under blue LED irradiation. Various reaction parameters like light intensity, sonication power, catalyst loading, and bacterial load were studied. Effective and complete disinfection was observed with a catalyst loading of 250 mg/L eradicating a bacterial concentration of 106 CFU/mL within 20 mins. Being a hybrid strategy, the catalyst concentration below the optimum (<1xMIC) was also able to provide significant disinfection majorly due to the synergistic effect. Primary mechanism of disinfection was inferred from the escape of intracellular nucleic acids suggesting disruption of cell membrane followed by ROS scavenging experiments which suggested the importance of various ROS species in the decontamination experiments. The stability of photocatalytic efficiency of the CdS nanorods even after multiple cycles of disinfection revealed possibilities of nanomaterial recycling for wastewater disinfection. The results suggest that the hybrid sono-photocatalytic approach can proficiently eliminate harmful multi-drug resistant bacteria and drastically reduce operational time. However, upscaling of the approach to disinfect actual wastewater remains to be investigated for environmental applications.

Aspergillus niger Culture Filtrate (ACF) Mediated Biocontrol of Enteric Pathogens in Wastewater

Robust control of pathogens in sewage facilitates safe reuse of wastewater rich in valuable nutrients for potential valorization through biological means. Aspergillus niger is widely reported in bioremediation of wastewater but studies on control of enteric pathogens in sewage are very sparse. So, this study aimed at exploring the antibacterial and nematicidal activity of A. niger culture filtrate (ACF). Antibacterial activity of ACF on enteric pathogens (Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio cholerae, Salmonella enterica, Shigella dysenteriae, Escherichia coli, Staphylococcus aureus, Klebsiella variicola) was determined by spectrophotometric growth analysis, resazurin based viability assay and biofilm formation assay. ACF showed inhibition against all enteric pathogens except Pseudomonas aeruginosa. Nematicidal studies on Caenorhabditis elegans showed 85% egg hatch inhibition and 52% mortality of L1 larvae. Sewage treatment with ACF at 1:1 (v/v) showed 2–3 log reduction in coliforms, Klebsiella, Shigella, Salmonella, S. aureus and Vibrio except Pseudomonas, indicating significant alteration of complex microbial dynamics in wastewater. Application of ACF can potentially be used as a robust biocontrol strategy against infectious microbes in wastewater and subsequent valorization by cultivating beneficial Pseudomonas.

Magnetic conjugated microporous polymer hollow spheres decorated with Fe3O4 nanoparticles for selective absorption and sterilization

Novel magnetic conjugated microporous polymer hollow spheres (CMP-HSs@Fe3O4) with high specific surface areas were synthesized for the absorption of antibiotics and the sterilization of microbes in wastewater, and possessed superior sterilization performance.

A Study on Survival and Chromate Reducing Ability of Bacterial Isolates in Tannery Effluent

Rapid industrialization coupled with rapid growth of human population has brought about hazards of environmental pollution. The tanning industry is a major source of water pollution and a threat to the environment due to indiscriminate use of chromium. The reduction-mediated immobilization of Cr (VI) to Cr (III) is a useful process for remediation of Cr (VI) affected environments. The conventional physico-chemical methods for the treatment of Cr (VI) contaminated soil and groundwater are relatively lengthy and expensive as they are energy intensive and require large quantities of chemical reagents which can sometimes generate secondary wastes that require subsequent disposal and do not completely reduce chromium (VI). In view of these treatment shortcomings microbial reduction of toxic hexavalent chromium can be obtained by utilizing microbes in waste water which is cost-effective process and does not produce secondary wastes. The present study aimed to identify and evaluate chromate reducing strains of bacteria from tannery effluent. Seven bacterial strains were isolated from tannery effluent and were identified as members of genera Staphylococcus, Bacillus, Citrobacter and Pseudomonas. The hexavalent chromium reduction and its simultaneous conversion to chromium (III) by the strains were studied in minimal broth medium (with glucose) containing potassium dichromate at various concentrations ranging from 250 mg/l to 1000 mg/l. All the isolates could grow as well as reduce Cr (VI) even at concentration of 1000 mg/l. Qualitative analysis of Cr (III) was also performed.

Pharmaceuticals and microbes in wastewater: An annotated selection of World Wide Web sites relevant to the topics in environmental microbiology.

Pharmaceuticals and microbes in wastewater: An annotated selection of World Wide Web sites relevant to the topics in environmental microbiology.

Biofouling control of a forward osmosis membrane during single-pass pre-concentration of wastewater

Pre-concentration of wastewater using a forward osmosis (FO) membrane prior to processing by an anaerobic digester can enhance biogas production. However, biofouling caused by microbes in wastewater remains a challenge. The study aimed to evaluate the efficacy of chloramination in mitigating the biofouling of an FO membrane during a single-pass concentration of primary wastewater effluent. Pre-disinfection at a chloramine dose of 22–121 mg/L successfully alleviated membrane fouling. Bacterial cell counts in the feed and concentrate showed that most of the bacterial cells in the wastewater were trapped on the membrane surface or spacer. The FO membrane surfaces in non-chloraminated/chloraminated systems were fully-covered by intact/damaged bacterial cells, respectively, indicating that chloramination effectively mitigated biofouling. However, due to high permeate-recovery and low cross-flow velocity in a single-pass concentration process, organic fouling on the membrane surface (and possibly on the interior wall of the membrane-pores) appeared to cause a gradual reduction in permeate-flux. This study demonstrated successful biofouling control using chloramination during a single-pass and high-recovery pre-concentration of primary wastewater effluent.

Characterization of biosynthesized silver nanoparticles by Haplophyllum tuberculatum plant extract under microwave irradiation and detecting their antibacterial activity against some wastewater microbes

Characterization of biosynthesized silver nanoparticles by Haplophyllum tuberculatum plant extract under microwave irradiation and detecting their antibacterial activity against some wastewater microbes

Wastewater biofilm formation on self-assembled monolayer surfaces using elastomeric flow cells

In anaerobic wastewater treatment, microbial biofilm is beneficial for efficient substrate utilization and for preventing the wash-out of key microorganisms. By providing solid supports, biofilm formation can be accelerated due to the early initial adhesion of residing microbes. Alteration in surface properties is therefore one such approach that helps us understand microbial interfacial interaction. Here, self-assembled monolayers of alkanethiols with carboxyl (-COOH), hydroxyl (-OH), and amine (-NH2) terminal moieties on gold (Au) substrates were employed to study the initial adhesion of wastewater microbes. An elastomeric flow cell was also utilized to simulate the environment of wastewater bioreactor. Results from fluorescence in situ hybridization (FISH) portrayed more enhanced microbial adhesion after 2 h on -NH2 functional group with the calculated surface coverage of 12.8 ± 2.4% as compared to 7.7 ± 1.6% on -COOH, 11.0 ± 2.0% on -OH, and 1.2% on unmodified Au surfaces. This might be because of concomitant electrostatic attraction between negatively-charged bacteria and positively-charged (-NH3+) functional groups. Nevertheless, the average surface coverage by individual biofilm clusters was 28.0 ± 5.0 μm2 and 32.0 ± 9.0 μm2 on -NH2 and -OH surfaces, respectively, while -COOH surfaces resulted in higher value (60.0 ± 5.0 μm2) and no significant cluster formation was observed on Au surfaces. Accordingly, the average inter-cluster distance observed on -NH2 surfaces was relatively smaller (3.0 ± 0.6 μm) as compared to that on other surfaces. Overall, these data suggest favorable initial biofilm growth on more hydrophilic and positively-charged surfaces. Furthermore, the analysis of the mean fluorescence intensity revealed preferred initial adhesion of key microbes (archaea) on -OH and -NH2 surfaces. Indeed, results obtained from this study would be beneficial in designing selective biointerfaces for certain biofilm carriers in a typical wastewater bioreactor. Importantly, our elastomeric flow cell integrated with SAM-modified surfaces demonstrated an ideal platform for high-throughput investigation of wastewater biofilm under controlled environments.

Removal of phenols-like substances in pharmaceutical wastewater with fungal bioreactors by adding Trametes versicolor.

Fungi are known to be more resistant to toxic compounds and more effective in removing recalcitrant organics such as phenols than bacteria. Here we examined the removal of phenols (as a component of Zopliclone drugs), added to non-sterile pharmaceutical wastewater with continuous treatment fungal bioreactor by its augmentation with mono-species of white-rot fungi (WRF) Trametes versicolor. Results showed that WRF in a sterile reactor (a batch mode) were moderately effective for removal of phenols (40% in seven days); however, native wastewater microbes at optimal conditions for fungi (pH 5.5, 25 °C) were more effective (90%, both in batch and continuous flow modes). In continuous flow mode, addition of WRF was an effective way to mitigate high loads of phenols (up to 400 mg/L), by both fungal enzymes (growth rate 0.075 h-1, laccase enzymatic activity 4 nkat/mL) and biosorption. The study confirmed that naturaly occuring fungi in combination with fungus-augmentation is an effective approach for treatment of high-strength pharmaceutical wastewater.

Removal of microbes from municipal wastewater effluent by rapid sand filtration and subsequent UV irradiation

The elimination of wastewater microbes is often necessary when effluent receiving waters are reused for different purposes e.g. for irrigation or as a raw water source of drinking water. In the present study, rapid sand filtration (SF) combined with the use of polyaluminium chloride coagulation was used as a pre-treatment to improve the quality of wastewater effluent before further treatment with UV irradiation. Pilot-scale experiments were run in four treatment plants in Finland. Treatment performance was followed by measuring physical and microbial parameters. Rapid sand filtration reduced suspended solids, turbidity and colour of effluents by about 90%, 70-80% and 20-50% respectively. It also improved the UV transmittance of water by up to 20%. Microbes and phosphorus were reduced by 90-99% and to 0.05 mg/L respectively. UV irradiation further reduced the number of microbes up to 99.9%. The efficiency of UV doses in pilot UV reactors was confirmed with collimated-beam device determinations and with added FRNA phages. More than 99.9% reduction of MS2 was achieved with the dose of 140mWs/cm2 in pilot UV reactors. Rapid sand filtration and the subsequent UV irradiation reduced the number of all the tested microbes to a low level, often below the detection limit. Suspended solids and the water turbidity were reduced to 1-2 mg/L and approximately 1 NTU respectively.

The Colours of Life: An Introduction to the Chemistry of Porphyrins and Related Compounds. Lionel R. Milgrom

Previous articleNext article No AccessNew Biological BooksThe Colours of Life: An Introduction to the Chemistry of Porphyrins and Related Compounds. Lionel R. Milgrom Dabney W. DixonDabney W. Dixon Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 75, Number 1Mar., 2000 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/393271 Views: 7Total views on this site Citations: 4Citations are reported from Crossref Copyright 2000 The University of ChicagoPDF download Crossref reports the following articles citing this article:Knowledge Siyabonga Ndlovu, Makwena Justice Moloto, Kutloano Edward Sekhosana, Thabo Thokozani Innocent Nkambule, Muthumuni Managa Porphyrins developed for photoinactivation of microbes in wastewater, Environmental Science and Pollution Research 30, no.55 (Dec 2022): 11210–11225.https://doi.org/10.1007/s11356-022-24644-8Baokun Liang, Yingying Zhang, Christopher Leist, Zhaowei Ou, Miroslav Položij, Zhiyong Wang, David Mücke, Renhao Dong, Zhikun Zheng, Thomas Heine, Xinliang Feng, Ute Kaiser, Haoyuan Qi Optimal acceleration voltage for near-atomic resolution imaging of layer-stacked 2D polymer thin films, Nature Communications 13, no.11 (Jul 2022).https://doi.org/10.1038/s41467-022-31688-4Biyang Hu, Qi Li, Hong Yu, Shaojun Du Identification and characterization of key haem pathway genes associated with the synthesis of porphyrin in Pacific oyster (Crassostrea gigas), Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 255 (Aug 2021): 110595.https://doi.org/10.1016/j.cbpb.2021.110595Maria Leonor Santos, Mariaelena D’Ambrosio, Ana P. Rodrigo, A. Jorge Parola, Pedro M. Costa A Transcriptomic Approach to the Metabolism of Tetrapyrrolic Photosensitizers in a Marine Annelid, Molecules 26, no.1313 (Jun 2021): 3924.https://doi.org/10.3390/molecules26133924