Bioremediation Research Articles

Abstract P1113: Patient-derived Cardiac Assembloids Enable Therapeutic Verification Of Regenerative Reagent Bio

Background: Preclinical study is a prerequisite for drug developments, and yet animal models are poor predictors in humans. We previously reported GSK3β inhibitor BIO (6-Bromoindirubin-3’-oxime) induced cardiac regeneration in zebrafish and rat models. Methods and Results: For further development of BIO in the models with human features, we generated human pluripotent stem cells (h-iPSCs) to get the cells which are components of heart. H-iPSCs were derived from blood mononuclear cells, or generated from fibroblasts isolated from the heart tissues of recipients after transplantation or from heart samples during autopsy. After confirming the cell markers, h-iPSCs were differentiated into cardiomyocytes (CM), cardiac myofibroblasts (MF), and macrophages (Mac). Decellularized extracellular matrix (dcECM) were extracted from hearts, and we developed spheroids with various combinations. Since CM hardly proliferate and excessive MF is accumulated in damaged heart, cardiac regeneration is challenged by reversal them. Firstly, the effective dosage of BIO was 0.5uM on human cells, while was 5uM on cardiac cells of mice and rats. On BIO treatment with 0.5μM for 3 days, the numbers of total CM and EdU-or Ki67-positive CM were higher in the BIO-treated CM spheroids. Conversely, viability, migration and collagen gel contraction activities of MF were substantially inhibited by BIO treatment. Conclusions: Because tremendous trials for regeneration have failed in clinical applications, it should be validated in realistic study designs with human cells. Here, we successfully reproduced the effects of BIO on human cardiac cells, and suggest the reciprocal regulation of CM and MF by BIO could be attractive therapeutic to heart diseases. More targeted approaches using human cardiac cells and dcECM might allow specific targeting of cardiovascular disease thus optimize regenerative therapy.

Ecological and health risk assessment associated with translocation of heavy metals in Lycopersicum esculentum from farmland soil treated with different composts

To meet the United Nations' Sustainable Development Goals, agricultural soil which is a non-renewable natural resource must be carefully managed. Heavy metals present in agricultural soil may imperil food security and instigate extreme risks to human health. Organic wastes have been long known for valuable amendments to soil thereby, improving overall soil health. In the present study, Echhornia crassipes, Hydrilla verticillata, and vegetable waste, was utilized to prepare compost amendments. Lycopersicum esculentum was used to metal uptake from compost amended soils. 5%, 10%, 15%, 25%, and 35% compost: soil (w/w) were studied to understand metal translocation in plants. Potential Ecological risk indices showed that while the degree of risk was medium for the natural soil, it reduced to slight for the soil amended with WHC and VWC for all compositions. The non-carcinogenic risks associated with the human health reduced on application of the composts, however, they still remained substantial for Fe, As, and Pb for WHC, HVC, and VWC composts at higher application ratios, especially among children. On the other hand, the carcinogenic health index values which were calculated to estimate the risk associated with ingestion of L. esculentum, showed a decrease in risk for all the metals studied, upon soil amendment. Soil amended with HVC compost showed an increase in carcinogenic risk for As, Pb, and Cr. Finally, we conclude that biological soil remediation is economical and a sustainable land management strategy that may lead to green and clean remediation solutions for metal contaminated soil.

Co-culture between Miscanthus x giganteus and Trifolium repens L. to enhance microbial activity, biomass and density in a PAH contaminated technosol

Phytoremediation is a biological soil remediation technique using plants and their associated microorganisms to clean-up contaminated soils and improve soils’ quality. We tested whether a co-culture between Miscanthus x giganteus (MxG) and Trifolium repens L. would enhance the soil biological quality. The objective was to determine the influence of MxG in mono- and in co-culture with white clover on the soil microbial activity, biomass and density. MxG was tested in mono- and in co-culture with white clover in a mesocosm over 148 days. The microbial respiration (CO2 production), the microbial biomass and the microbial density of the technosol were measured. Results showed that MxG induced an increase in microbial activity in the technosol compared to the non-planted condition with the co-culture having a greater impact. Regarding the bacterial density, MxG in mono- and in co-culture significantly increased the 16S rDNA gene copy number. The co-culture increased the microbial biomass, the fungal density and stimulated the degrading bacterial population, contrary to the monoculture and the non-planted condition. We can conclude the co-culture between MxG and white clover was more interesting than MxG monoculture in regards to the technosol biological quality and its potential for PAH remediation improvement.

A review on the adsorption of diuron, carbaryl, and alachlor using natural and activated clays

AbstractPesticides are considered predominant organic pollutants because they are widespread in many ecosystems. Pesticide residues can degrade chemically, physically, and biochemically in nature, but, because of their high stability and, in some cases, water solubility, they continue to persist in the environment. Pesticides have been eliminated from contaminated waters using a variety of methods that fall under the categories of biological, chemical, physical, and physicochemical remediation processes from various types of matrices, including water and soil. Due to their excellent qualities as adsorbents and pesticide transporters, the use of natural soil components such as clays, iron oxides, or humic acid has recently attracted growing interest. Clays have several advantages over other adsorbents, including large specific surface areas due to their small particle size, low cost, and widespread availability. Clay minerals have a great capacity for adsorption due to Coulombic forces and, attributable to their large surface area, van der Waals forces. This review describes historical, current, and emerging techniques and materials to remove the pesticides diuron, carbaryl, and alachlor using clays as adsorbents.

Long-term comparison of the performance of biostimulation and phytoextraction in soil contaminated with diesel and heavy metals

The long-term remediation performance under the natural conditions is required to establish the appropriate remediation strategy for contaminated soil. The objective of this study was to compare the long-term remediation efficiency of biostimulation and phytoextraction in contaminated soil containing petroleum hydrocarbons (PHs) and heavy metals. Two types of contaminated soil (soil contaminated with diesel only and co-contaminated with diesel and heavy metals) were prepared. For the biostimulation treatments, the soil was amended with compost, whereas maize, a representative phytoremediation plant, was cultivated for the phytoextraction treatments. There was no significant difference in remediation performance of biostimulation and phytoextraction in the diesel-contaminated soil, in which the maximum total petroleum hydrocarbon (TPH) removability was 94–96% (p < 0.05). However, phytoextraction exhibited the higher removability for TPH and heavy metals than biostimulation in the co-contaminated soil. There was no considerable change in the TPH removal in biostimulation (16–25%), while phytoextraction showed a 75% of TPH removal rate in the co-contaminated soil. Additionally, no significant changes were observed in heavy metals concentration of biostimulation, whereas the removability of heavy metals was 33–63% in phytoextraction. Meanwhile, maize, which is a suitable plant for phytoextraction, showed a translocation factor (translocating efficiency from roots to shoots) value of >1. Correlation analysis revealed that soil properties (pH, water content, and organic content) negatively correlated with pollutants removal. Additionally, the soil bacterial communities were changed over the investigated period, and the types of pollutants exerted a significant influence on the bacterial community dynamics. This study performed a pilot-scale comparison of two types of biological remediation technologies under natural environmental conditions and provided information on changes in the bacterial community structures. This study can be useful for establishing appropriate biological remediation methods to restore soil contaminated with PHs and heavy metals.

ADVANTAGEOUS OF BENEFICIAL MICROBES FOR BIOREMEDIATION OF ADULTERATED GLOBAL-CULTIVATED SOILS

The soil is one of the most valuable resources since it forms the foundation for many important life processes and ecosystem purposes. Worldwide, soil pollution is a result of human activities that are not sustainable, such as the use of dangerous inorganic chemicals. The mining, production, transportation, end-user use, disposal, and accidental discharge of chemicals all contribute to soil contamination, which in turn jeopardizes human life, livestock, wildlife, and entire ecosystems. Purifying and decontaminating soil with conventional procedures is labor-intensive and time-consuming and can modify the soil’s physical, chemical, and biological properties. Furthermore, they do not always ensure that all impurities are eliminated. Sustainable and cutting-edge technology has developed over the last few decades. Biological soil remediation solutions, also known as soft remediation options, are being developed to integrate, namely efficient removal of soil contaminants, mitigation of soil ecotoxicity, and reduction of legally and ethically mandated hazards to the environment and human health. Soil remediation methods should not only repair soil health and provide necessary system services but also reduce noxious waste concentrations in the soil to below regulatory limits. The microorganisms have shown promise in the clean-up of soils contaminated with radioactive contaminants, heavy metals, chemical fertilizers in excess, trichlorethylene, trinitrotoluene, herbicides such as atrazine, and organophosphates. The cost of cleaning up environmental pollutants with eco-friendly technology is inexpensive when compared to other approaches, including conventional ones. The focus of the current manuscript is on using beneficial bacteria to clean up polluted farmland to ensure the longevity of the subsequent generation.

Fungal-Based Remediation in the Treatment of Anthropogenic Activities and Pharmaceutical-Pollutant-Contaminated Wastewater

Pharmaceutical personal care products (PPCPs) have increased in consumption due to the worldwide post-pandemic situation, marking them as chemical and pathogenic pollutants in significantly higher concentrations than ever in the ecosystem. Considering the inexplicable levels of these chemical residues discharged into the environment, concerns have been raised regarding their probable ecotoxicity to marine and terrestrial life. A further concern is the potential for developing and spreading antibiotic-resistant microorganisms and genes in aquatic ecosystems due to antibiotic exposure. Hence, knowing how these compounds impact aquatic ecosystem functioning is imperative, and thus is a critical area of research. The ecological risk analysis of PPCPs in aquatic ecosystems has been carried out using various strategies. Previous studies have reported numerous approaches for eliminating these PPCPs, including conventional treatment methods, activated sludge processes, generated wetlands, biological remediation, sequencing batch reactors, phytoremediation, and membrane bioreactors. In terms of green biotechnology approaches, the current research aims to discover effective procedures for removing PPCPs and their emerging resources as pollutants. Therefore, this review focuses on the over-extensive utilization of PPCPs and their emergent sources responsible for the contamination and environmental threat for future wastewater purposes. Further, as fungi and their enzymes and derivatives can remove pharmaceuticals and personal care products from wastewater through oxidation and several processes, they have attracted the attention of the scientific community due to their ability to remove PPCPs as pollutants and their status as emerging resources in wastewater. This review examines the fundamental approach and progress of the bioremediation of pharmaceutical- and personal-care-contaminated wastewater using fungal-based systems. It also discusses mechanistic approaches through hybridizing cultures and other biological systems with fungal strains, current technologies, and prospects for future research on PPCPs in wastewater treatment.

Physico-chemical and biological remediation techniques for the elimination of endocrine-disrupting hazardous chemicals

Due to their widespread occurrence and detrimental effects on human health and the environment, endocrine-disrupting hazardous chemicals (EDHCs) have become a significant concern. Therefore, numerous physicochemical and biological remediation techniques have been developed to eliminate EDHCs from various environmental matrices. This review paper aims to provide a comprehensive overview of the state-of-the-art remediation techniques for eliminating EDHCs. The physicochemical methods include adsorption, membrane filtration, photocatalysis, and advanced oxidation processes. The biological methods include biodegradation, phytoremediation, and microbial fuel cells. Each technique's effectiveness, advantages, limitations, and factors affecting their performance are discussed. The review also highlights recent developments and future perspectives in EDHCs remediation. This review provides valuable insights into selecting and optimizing remediation techniques for EDHCs in different environmental matrices.

Responses of rhizosphere microbial community structure and metabolic function to heavy metal coinhibition.

Metal mineral mining results in releases of large amounts of heavy metals into the environment, and it is necessary to better understand the response of rhizosphere microbial communities to simultaneous stress from multiple heavy metals (HMs), which directly impacts plant growth and human health. In this study, by adding different concentrations of cadmium (Cd) to a soil with high background concentrations of vanadium (V) and chromium (Cr), the growth of maize during the jointing stage was explored under limiting conditions. High-throughput sequencing was used to explore the response and survival strategies of rhizosphere soil microbial communities to complex HM stress. The results showed that complex HMs inhibited the growth of maize at the jointing stage, and the diversity and abundance of maize rhizosphere soil microorganisms were significantly different at different metal enrichment levels. In addition, according to the different stress levels, the maize rhizosphere attracted many tolerant colonizing bacteria, and cooccurrence network analysis showed that these bacteria interacted very closely. The effects of residual heavy metals on beneficial microorganisms (such as Xanthomonas, Sphingomonas, and lysozyme) were significantly stronger than those of bioavailable metals and soil physical and chemical properties. PICRUSt analysis revealed that the different forms of V and Cd had significantly greater effects on microbial metabolic pathways than all forms of Cr. Cr mainly affected the two major metabolic pathways: microbial cell growth and division and environmental information transmission. In addition, significant differences in rhizosphere microbial metabolism under different concentrations were found, and this can serve as a reference for subsequent metagenomic analysis. This study is helpful for exploring the threshold for the growth of crops in toxic HM soils in mining areas and achieving further biological remediation.

Nano-bioremediation: an eco-friendly and effective step towards petroleum hydrocarbon removal from environment

Global concern about petroleum hydrocarbon pollution has intensified and gained scientific interest due to its noxious nature, high persistence in environmental matrices, and low degradability. One way to address this is by combining remediation techniques that could overcome the constraints of traditional physio-chemical and biological remediation strategies. The upgraded concept of bioremediation to nano-bioremediation in this direction offers an efficient, economical, and eco-friendly approach to mitigate petroleum contaminants. Here, we review the unique attributes of different types of nanoparticles and their synthesis procedures in remediating various petroleum pollutants. This review also highlights the microbial interaction with different metallic nanoparticles and their consequential alteration in microbial as well as enzymatic activity which expedites the remediating process. Besides, the latter part of the review explores the application of petroleum hydrocarbon degradation and the application of nano supports as immobilizing agents for microbes and enzymes. Further, the challenges and the future prospects of nano-bioremediation have also been discussed.

Hydrocarbon bioremediation in a pilot-scale: A combination of bioaugmentation, phytoremediation, and vermiremediation

This work aimed to validate the removal of total petroleum hydrocarbons (TPH) in a pilot system (on-site). Six piles of oil-contaminated soil were treated with 1) bioremediation (BIO) by three simultaneous technologies (bioaugmentation (bacterial consortium), phyto- (Panicum maximum) and vermiremediation (Pontoscolex corethrurus)), and compared with 2) natural attenuation (NA). Removal of alkanes, polycyclic aromatics (PAH), total petroleum hydrocarbons (TPH), and bacterial diversity were evaluated at 0, 35, 70, and 112 days. Biomass and number of shoots of P. maximum, the secondary vegetation, and the abundance of meso and macrofauna were measured initially and at the end. After 112 days, BIO significantly removed more alkanes (76%), PAH (68%), and TPH (76%) than NA treatment (23%, 19%, 24%). P. maximum biomass increased significantly (300%), with 97.3 ± 11.8 shoots m−2. After 112 days, the secondary plants Lippia dulcis, Taraxacum officinale, Bidens pilosa and bacterial phylum Actinobacteria (18%) were the most abundant. The abundance of the earthworm Protozapotecia australis was reduced, while the most abundant group of mesofauna was Acari (56%–71%). This combination of technologies improved the development of grass and secondary plants, which generated a more favorable microhabitat for soil organisms to remove TPH more efficiently.

Sustained-release of nutrients by yeast extract-loaded halloysite nanotubes supports bacterial growth

Halloysite nanotubes (Hal) have been researched as carriers of various active compounds and polymer additives. Hal reinforced the polymers, while a designated trigger mechanism initiates the release of active compounds. Encapsulation of microbiological agents has been attempted to develop biological self-healing concrete, soil treatment, and environmental remediation, among others. Considering the lack of attention devoted to studying the encapsulation of the nutrients required for biological action and their release, this report presents the preparation and characterization of Hal loaded with the common microbiological nutrient yeast extract (YE) as a multifunctional nanocomposite carrier of microbiological nutrients. YE was loaded on the outer surface and inside the lumen of the Hal by using vacuum entrapment to prepare the YE-loaded Hal (HY) nanocomposites. Thermogravimetric analysis and UV–visible absorbance were used to quantify the loading and the release of YE from HY nanocomposites, showing increasing YE loading after the vacuum treatment and with higher Hal: YE ratios. Vacuumed 1:3 HY samples presented the best sustained-release profile. Field-emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FE-SEM-EDX), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), and X-Ray diffraction analysis (XRD) showed blocked lumens, and successful lumen loading of YE particles after the vacuum treatment and Hal-YE attachment by weak electrostatic bonding. Inter-particle YE-YE interactions were also evident. The YE loading procedure did not impact the interlayer space of Hal and lowered the crystallinity of the nanotubes. The HY nanocomposite effectively supported spore germination and bacterial growth, resulting in higher bacterial concentrations than conventional media after the expected bacterial death phase. The composition of the HY nanocomposite is easily adjustable, and the unloaded YE can be reused.

Microplastics as an emerging menace to environment: Insights into their uptake, prevalence, fate, and sustainable solutions

The inflated demand for plastic products has led to tremendous rise in plastic debris in different environmental matrices, thereby resulting in plastic pollution. This affects plants, animals, and even humans, as microplastics can enter the food chain and cause several health implications. Microplastics are the small plastic particles (size below 5 mm) that are largely debated nowadays owing to their environmental risk assessment. Their potential to interact with other toxic contaminants, their tendency to be ingested or taken up by living organisms and their longevity is a serious threat to our environment. However, despite wealth of recent information, still there is a gap, particularly in eco-toxicology studies, fate, prevalence and feasible solutions to cope up with the menace of microplastics pollution. This review unravels the environmental fate and behaviour of microplastics as well as their global distribution in the marine and terrestrial environment. Furthermore, we aim to contribute to the international debate on the microplastics global paradigm. We briefly suggest sustainable solutions and recommendations to achieve future research goals on microplastics. Our review reveals some of the newest biological (green algae and modified sponges) and physical (nano-particles and membrane treatment) remediation solutions to eradicate microplastics from different types of environment. This review presents a critical evaluation of the state of knowledge of micro-plastics and suggested some recommendations which can help in identifying some important key questions for future research.

Global Situation of Bioremediation of Leachate-Contaminated Soils by Treatment with Microorganisms: A Systematic Review.

This systematic review presents the current state of research in the last five years on contaminants in soils, especially in leachates from solid waste landfills, with emphasis on biological remediation. In this work, the pollutants that can be treated by microorganisms and the results obtained worldwide were studied. All the data obtained were compiled, integrated, and analyzed by soil type, pollutant type, bacterial type, and the countries where these studies were carried out. This review provides reliable data on the contamination of soils worldwide, especially soils contaminated by leachate from municipal landfills. The extent of contamination, treatment objectives, site characteristics, cost, type of microorganisms to be used, and time must be considered when selecting a viable remediation strategy. The results of this study can help develop innovative and applicable methods for evaluating the overall contamination of soil with different contaminants and soil types. These findings can help develop innovative, applicable, and economically feasible methods for the sustainable management of contaminated soils, whether from landfill leachate or other soil types, to reduce or eliminate risk to the environment and human health, and to achieve greater greenery and functionality on the planet.

Carbonate precipitation and nitrogen fixation in AMG (Artificial Martian Ground) by cyanobacteria

This article describes experiments performed to study the survival, growth, specific adaptations and bioremediation potential of certain extreme cyanobacteria strains within a simulation of the atmospheric composition, temperature and pressure expected in a future Martian greenhouse. Initial species have been obtained from Mars-analogue sites in Georgia. The results clearly demonstrate that specific biochemical adaptations allow these autotrophs to metabolize within AMG (Artificial Martian Ground) and accumulate biogenic carbon and nitrogen. These findings may thus contribute to the development of future Martian agriculture, as well as other aspects of the life-support systems at habitable Mars stations. The study shows that carbonate precipitation and nitrogen fixation, performed by cyanobacterial communities thriving within the simulated Martian greenhouse conditions, are cross-linked biological processes. At the same time, the presence of the perchlorates (at low concentrations) in the Martian ground may serve as the initial source of oxygen and, indirectly, hydrogen via photo-Fenton reactions.Various carbonates, ammonium and nitrate salts were obtained as the result of these experiments. These affect the pH, salinity and solubility of the AMG and its components, and so the AMG's scanty biogenic properties improved, which is essential for the sustainable growth of the agricultural crops. Therefore, the use of microorganisms for the biological remediation and continuous in situ fertilization of Artificial Martian Ground is possible.

Demonstration and evaluation of commercial and municipal equipment for urban biological decontamination.

Large-scale biological contamination incidents pose unique yet significant challenges to remediation operations. Previous incidents have demonstrated the utility of readily available commercial and municipal equipment for conducting remediation tasks. Preidentification and evaluation of such equipment could reduce lag time for response initiation and enhance overall response effectiveness and efficiency. The current study aimed to identify commercial and municipal equipment that could be beneficial in wide-area biological remediation operations. Equipment were identified by market research, their utility was assessed by a group of subject matter experts, and a subset of those equipment was observed under operational conditions in a realistic urban environment. Observations and feedback from demonstration participants are presented within the article. This information is intended to support rapid decision-making following large-scale biological incidents, broaden the universe of potentially useful equipment to support the response, enhance response operations, and reduce the impact on the public.

Providencia alcalifaciens—Assisted Bioremediation of Chromium-Contaminated Groundwater: A Computational Study

In Saudi Arabia, seawater desalination is the primary source of acquiring freshwater, and groundwater contains a high concentration of toxic heavy metals. Chromium (Cr) is one of the heavy metals that is widely distributed in the environment, particularly in the groundwater of Madinah. Diverse techniques are employed to eliminate the toxicity of heavy metals from the environment, but, lately, the focus has shifted to biological remediation systems, due to their higher removal efficiencies, lower costs, and more ecologically benign characteristics than the conventional methods. Providencia bacteria engage in a variety of adsorption processes to interact with heavy metals. In this study, we aim to investigate the role of potential active site residues in the bioengineering of chromate reductase (ChrR) from Providencia alcalifaciens to reduce the Cr to a lesser toxic form by employing robust computational approaches. This study highlights Cr bioremediation by providing high-quality homology-modeled structures of wild type and mutants and key residues of ChrR for bioengineering to reduce the Cr toxicity in the environment. Glu79 is found to be a key residue for Cr binding. The mutant models of Arg82Cys, Gln126Trp, and Glu144Trp are observed to establish more metallic interactions within the binding pocket of ChrR. In addition, the wild type ChrR (P. alcalifaciens) has been found to be unstable. However, the mutations stabilized the structure by preserving the metallic contacts between the critical amino acid residues of the identified motifs and the Cr(VI). Therefore, the mutants discovered in the study can be taken into account for protein engineering to create reliable and effective enzymes to convert Cr(VI) into a lesser toxic form.

Isolation and identification of naturally occurring textile effluent-degrading bacteria and evaluation of their ability to inhibit potentially toxic elements

Untreated textile dye-contaminated wastewater contains potentially toxic elements (PTEs) and causes pollution when discharged. Herein, we attempted to isolate and identify naturally occurring effluent-degrading bacteria and investigate their resistance potentials against various PTEs. Wastewater samples were collected from the biological effluent treatment plant of a textile dyeing industry located at the Chattogram Export Processing Zone, Bangladesh. The effluent samples contained Pb and Cr, with 27 times higher Cr content than the regulatory limit. A total of 14 bacterial isolates were isolated from the effluent based on differences in their cultural properties. Based on morphological and biochemical features, isolates were identified as Staphylococcus xylosus, Bacillus korlensis, Pseudomonas fluorescens, Pseudomonas cichorii, Brevundimonus diminuta, and Enterococcus columbae. Isolates were primarily screened for their ability to reduce the content of PTEs, such as Cr, Pb, Mn, Cu, and Cd. Pre-incubation of effluents and isolates revealed that most bacteria reduced the PTEs in the effluent. Of the 14 isolates, six exhibited potential in reducing most of the PTEs—Cd (94–99%). Further, Cr was decreased by 68 and 61% in the presence of S. xylosus and P. fluorescens, respectively, after 72 h of incubation in a medium containing 400 mg L−1 salt. The findings of this study can provide insights into the efficient biological remediation of PTEs in industrial wastewater.

An Eco-Benign Biomimetic Approach for the Synthesis of Ni/ZnO Nanocomposite: Photocatalytic and Antioxidant Activities.

With the increasing demand for wastewater treatment and multidrug resistance among pathogens, it was necessary to develop an efficient catalyst with enhanced photocatalytic and antibacterial applications. The present study proposes a facile and green strategy for synthesizing zinc oxide (ZnO) decorated nickel (Ni) nanomaterials. The synthesized Ni/ZnO nanocomposite displays a high crystallinity and spherical morphology, which was systematically characterized by XRD, SEM, FT-IR, UV-visible spectroscopy, EDX, HRTEM, and XPS techniques. In addition, the bacteriological tests indicated that Ni/ZnO nanocomposite exhibits potent antibacterial activity against human pathogens, i.e., Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). The inhibition zone observed in light and dark conditions for E. coli was 16 (±0.3) mm and 8 (±0.4) mm, respectively, which confirms the high efficacy of the nanocomposite in the presence of light compared to dark conditions. The detailed inhibition mechanism of said bacterium and damage were also studied through fluorescence spectroscopy and SEM analysis, respectively. Evaluation of antioxidant activity based on free radical scavenging activity revealed that the Ni/ZnO nanocomposite effectively scavenges DPPH. In the photocatalytic performance, the Ni/ZnO nanocomposite exhibited a remarkable degradation ability under the optimized condition, which was attributed to their controllable size, high surface area, and exceptional morphology. Good selectivity, high photodegradation, and antibacterial activities and satisfactory hemolytic behavior of the as-prepared nanocomposite make them able to become a potential candidate for superior biological performance and environmental remediation.

Microplastics: The stemming environmental challenge and the quest for the missing mitigation strategies

Repetitious manufacturing, usage and irresponsible disposal trigger the breakdown of primary and secondary plastics, ending up in aquatic, terrestrial, and pristine locations like arctic tundra due to their diaphanous property. Owing to their origin, size, interaction with other contaminants, and chemical behavior they can be very idiosyncratic; they not only accumulate in the ecosystem, imparting chemical alterations but also are being consumed by the aquatic and terrestrial animals leading to hazardous consequences. Washing machine wastewater significantly contribute to the global microplastic load. For the past few years, microplastics (MP) and microfibers (MF) have been contaminants of grave concern pertaining to their deleterious nature against human, marine, and ecosystem health and grabbed the attention of environmental researchers. This review sums up the inimical ramifications of these tiny particles on biota, their types and characterization strategies, along with the biological removal strategies of these plastics and fibers highlighting the circular economy approach to limit them in the source and the enzymatic pathways regulating their eradication. Additionally, there are several research gaps in the biological remediation of these particles, which can be explored further to develop distinct, lucrative and ecologically reliable technologies for combating this mammoth (ironically) environmental adulterants.