β-cyclodextrin polymer composites for the removal of pharmaceutical substances, endocrine disruptor chemicals, and dyes from aqueous solution- A review of recent trends

Cyclodextrin (CD) and its derivatives are receiving attention as a new-generation adsorbent for water pollution treatment due to their external hydrophilic and internal hydrophobic properties. Among types of CD, β-Cyclodextrin (βCD) has been a material of choice with a proven track record for a range of utilities in distinct domains, owing to its unique cage-like structural conformations and inclusion complex-forming ability, especially to mitigate emerging contaminants (ECs). This article outlines βCD composites in developing approaches of their melds and composites for purposes such as membranes for removal of the ECs in aqueous setups have been explored with emphasis on recent trends. Electrospinning has bestowed an entirely different viewpoint on polymeric materials, comprising βCD, in the framework of diverse functions across a multitude of niches. Besides, this article especially discusses βCD polymer composite membrane-based removal of contaminants such as pharmaceutical substances, endocrine disruptors chemicals, and dyes. Finally, in this article, the challenges and future directions of βCD-based adsorbents are discussed, which may shed light on pragmatic commercial applications of βCD polymer composite membranes.

Recent progress in polysaccharide and polypeptide based modern moisture-retentive wound dressings

Wounds were considered as defects in the tissues of the human skin and wound healing is said to be a tedious process as there are possibilities of infection or inflammation due to microorganisms. Modern moisture-retentive wound dressing (MMRWD) is opening a new window toward wound therapy. It comprises different types of wound dressing that has classified based on their functionality. Selective polysaccharide-polypeptide fiber composite materials such as hydrogels, hydrocolloids, hydro fibers, transparent-film dressing, and alginate dressing are discussed in this review as a type of MMRWD. The highlight of this polysaccharide and polypeptide based MMRWD is that it supports and enhances the healing of different types of wounds by moisture absorption thus preventing infection. This study has given enlightenment on the application of selected polysaccharide and polypeptide based MMRWD that enhances wound healing actions still it has been observed that the composite wound healing dressing is more effective than the single one. The nano-sized materials (synthetic nano drugs and phyto drugs) were found to increase the efficiency of healing action while coated in the wound dressing material. Future research is required to find out more possibilities of the different composite types of wound dressing in the healing action.

Advanced technologies for the determination of quantitative structure-activity relationships and degradation efficiency of micropollutants and their removal in water - A review

The growing concentrations of micropollutants in aquatic ecosystems are a global water quality issue. Understanding micropollutants varied chemical composition and potency is essential to solving this complex issue. Micropollutants management requires identifying contaminants to reduce, optimal reduction targets, and the best wastewater recycling locations. Management requires appropriate technological measures. Pharmaceuticals, antibiotics, hormones, and other micropollutants can enter the aquatic environment from point and diffuse sources, with wastewater treatment plants (WWTPs) distributing them in urban areas. Micropollutants like pharmaceuticals and hormones may not be removed by conventional WWTPs. Micropollutants affect the EU, especially in densely populated areas where surface water is consumed. This review examines several technological options that can be integrated into existing treatment methods to address this issue. In this work, oxidation, activated carbon, and their combinations as potential solutions, considering their efficacy and cost were evaluated. This study illuminates micropollutants origin and physico-chemical properties, which affect distribution, persistence, and environmental impacts. Understanding these factors helps us develop targeted micropollutant mitigation strategies to protect water quality. This review can inform policy and decision-making to reduce micropollutant impacts on aquatic ecosystems and human health.

Multi-faceted CRISPR-Cas9 strategy to reduce plant based food loss and waste for sustainable bio-economy - A review

Currently, international development requires innovative solutions to address imminent challenges like climate change, unsustainable food system, food waste, energy crisis, and environmental degradation. All the same, addressing these concerns with conventional technologies is time-consuming, causes harmful environmental impacts, and is not cost-effective. Thus, biotechnological tools become imperative for enhancing food and energy resilience through eco-friendly bio-based products by valorisation of plant and food waste to meet the goals of circular bioeconomy in conjunction with Sustainable Developmental Goals (SDGs). Genome editing can be accomplished using a revolutionary DNA modification tool, CRISPR-Cas9, through its uncomplicated guided mechanism, with great efficiency in various organisms targeting different traits. This review's main objective is to examine how the CRISPR-Cas system, which has positive features, could improve the bioeconomy by reducing food loss and waste with all-inclusive food supply chain both at on-farm and off-farm level; utilising food loss and waste by genome edited microorganisms through food valorisation; efficient microbial conversion of low-cost substrates as biofuel; valorisation of agro-industrial wastes; mitigating greenhouse gas emissions through forestry plantation crops; and protecting the ecosystem and environment. Finally, the ethical implications and regulatory issues that are related to CRISPR-Cas edited products in the international markets have also been taken into consideration.

Carbon-based nanomaterial intervention and efficient removal of various contaminants from effluents - A review

Water treatment is a worldwide issue. This review aims to present current problems and future challenges in water treatments with the existing methodologies. Carbon nanotube production, characterization, and prospective uses have been the subject of considerable and rigorous research around the world. They have a large number of technical uses because of their distinct physical characteristics. Various catalyst materials are used to make carbon nanotubes. This review's primary focus is on integrated and single-treatment technologies for all kinds of drinking water resources, including ground and surface water. Inorganic non-metallic matter, heavy metals, natural organic matter, endocrine-disrupting chemicals, disinfection by-products and microbiological pollutants are among the contaminants that these treatment systems can remediate in polluted drinking water resources. Significant advances in the antibacterial and adsorption capabilities of carbon-based nanomaterials have opened up new options for excluding organic/inorganic and biological contaminants from drinking water in recent years. The advancements in multifunctional nanocomposites synthesis pave the possibility for their use in enhanced wastewater purification system design. The adsorptive and antibacterial characteristics of six main kinds of carbon nanomaterials are single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphene oxide, fullerene and single-walled carbon nanohorns. This review potentially addressed the essential metallic and polymeric nanocomposites, are described and compared. Barriers to use these nanoparticles in long-term water treatment are also discussed.

Bioprospecting of novel peroxidase from Streptomyces coelicolor strain SPR7 for carcinogenic azo dyes decolorization

Peroxidase (POX) is a heme-containing oxidoreductase, its voluminous immuno-diagnostic and bioremediatory intuitions have incited optimization and large scale-generation from novel microbial repertoires. Azo dyes are the most detrimental classes of synthetic dyes and they are the common ecotoxic industrial pollutants in wastewater. In addition, azo dyes are refractory to degradation owing to their chemical nature, comprising of azoic linkages, amino moieties with recalcitrant traits. Moreover, they are major carcinogenic and mutagenic on humans and animals, whereby emphasizing the need for decolorization. In the present study, a novel POX from Streptomyces coelicolor strain SPR7 was investigated for the deterioration of ecotoxic dyestuffs. The initial medium component screening for POX production was achieved using, One Factor at a Time and Placket-Burman methodologies with starch, casein and temperature as essential parameters. In auxiliary, Response Surface Methodology (RSM) was recruited and followed by model validation using Back propagation algorithm (BPA). RSM-BPA composite approach prophesied that combination of starch, casein, and temperature at optimal values 2.5%, 0.035% and 35 °C respectively, has resulted in 7 folds enhancement of POX outturn (2.52 U/mL) compared to the unoptimized media (0.36 U/mL). The concentrated enzyme decolorized 75.4% and 90% of the two azo dyes with lignin (10 mM), respectively. Hence, this investigation confirms the potentiality of mangrove actinomycete derived POX for elimination of noxious azo dyes to overcome their carcinogenic, mutagenic and teratogenic effects on humans and aquatic organisms.

Polymeric biomolecules based nanomaterials: Production strategies and pollutant mitigation as an emerging tool for environmental application

The ever-exploding global population coupled with its anthropogenic impact has imparted unparalleled detrimental effects on the environment and mitigating them has emerged as the prime challenge and focus of the current century. The niche of nanotechnology empowered by composites of biopolymers in the handling of xenobiotics and environmental clean-up has an unlimited scope. The appositeness of biopolymer-nanoparticles (Bp-NPs) for environmental contaminant mitigation has received unique consideration due to its exclusive combination of physicochemical characteristics and other attributes. The current review furnishes exhaustive scrutiny of the current accomplishments in the development of Bp-NPs and biopolymer nanomaterials (Bp-NMs) from various polymeric biomolecules. Special attention was provided for polymeric biomolecules such as cellulose, lignin, starch, chitin, and chitosan, whereas limited consideration on gelatin, alginate, and gum for the development of Bp-NPs and Bp-NMs; together with coverage of literature. Promising applications of tailored biopolymer hybrids such as Bp-NPs and Bp-NMs on environmentally hazardous xenobiotics handling and pollution management are discussed as to their notable environmental applications.

Removal of nanoplastics in water treatment processes: A review

Nanoplastics are drawing a significant attention as a result of their propensity to spread across the environment and pose a threat to all organisms. The presence of nanoplastics in water is given attention nowadays as the transit of nanoplastics occurs through the aquatic ecosphere besides terrestrial mobility. The principal removal procedures for macro-and micro-plastic particles are effective, but nanoparticles escape from the treatment, increasing in the water and significantly influencing the society. This critical review is aimed to bestow the removal technologies of nanoplastics from aquatic ecosystems, with a focus on the treatment of freshwater, drinking water, and wastewater, as well as the importance of transit and its impact on health concerns. Still, there exists a gap in providing a collective knowledge on the methods available for nanoplastics removal. Hence, this review offered various nanoplastic removal technologies (microorganism-based degradation, membrane separation with a reactor, and photocatalysis) that could be the practical/effective measures along with the traditional procedures (filtration, coagulation, centrifugation, flocculation, and gravity settling). From the analyses of different treatment systems, the effectiveness of nanoplastics removal depends on various factors, source, size, and type of nanoplastics apart from the treatment method adopted. Combined removal methods, filtration with coagulation offer great scope for the removal of nanoplastics from drinking water with >99 % efficiency. The collected data could serve as base-line information for future research and development in water nanoplastics cleanup.

Trends and thresholds on bacterial degradation of bisphenol-A endocrine disruptor - a concise review

Bisphenol-A (BPA) is a monomer found in polycarbonate plastics, food cans, and other everyday chemicals; this monomer and its counterparts are widely used, culminating in its presence in water, soil, sediment, and the atmosphere. Furthermore, because of its estrogenic and genotoxic properties, it has been acknowledged as an endocrine disruptor; contamination of BPA in the environment is becoming a growing concern, and ways to effectively mitigate BPA from the environment are currently explored. Hence, the focal point of the review is to collate the bacterial degradation of BPA with the proposed degradation mechanism, explicitly focusing on researches published between 2017 and 2022. BPA breakdown is dependent primarily on bacterial metabolism, although numerous factors influence its fate in the environment. The metabolic routes for BPA breakdown in crucial bacterial strains were postulated, sourced on the transformed metabolite-intermediates perceived through degradation; enzymes and genes associated with the bacterial degradation of BPA have also been included in this review. This review will be momentous to generate a conceptual strategy and stimulate the progress on bacterial mitigation of BPA as a path to a sustainable cleaner environment.

Graphene oxide-based nanomaterials for the treatment of pollutants in the aquatic environment: Recent trends and perspectives - A review

Graphene oxide can be used to store energy, as electrodes and purify industrial and domestic wastewater as photocatalysts and adsorbents because of its remarkable thermal, electrical, and chemical capabilities. Toward understanding graphene oxide (GO) based nanomaterials considering the background factors, the present review study investigated their characteristics, preparation methods, and characterization processes. The removal of contaminants from wastewater has recently been a focus of attention for materials based on GO. Progress in GO synthesis and surface modification has shown that they can be used to immobilize enzymes. It is possible to immobilize enzymes with varying characteristics on graphene-oxide-based substrates without sacrificing their functioning, thus developing a new environmental remediation platform utilizing nano biocatalysts. GO doping and co-doping with a variety of heterogeneous semiconductor-based metal oxides were included in a brief strategy for boosting GO efficiency. A high band-gap material was also explored as a possibility for immobilization, which shifts the absorption threshold to the visible range and increases photoactivity. For water treatment applications, graphene-based nanomaterials were used in Fenton reactions, photocatalysis, ozonation, photo electrocatalysis, photo-Fenton, and a combination of photon-Fenton and photocatalysis. Nanoparticles made from GO improved the efficiency of composite materials when used for their intended applications. As a result of the analysis, prospects and improvements are clear, especially when it comes to scaling up GO-based wastewater treatment technologies.

Synthesis and characterization of lanthanum-based metal organic framework decorated polyaniline for effective adsorption of lead ions from aqueous solutions

The novel La-MOF@x%PANI composite was synthesized via a two-step procedure with ultra-sonication, and the adsorption mechanism of Pb²⁺ ions from synthetic aqueous solutions was systematically studied. The Pb²⁺ adsorption on the La-MOF@x%PANI was evaluated by the Fourier transform infrared spectroscopy, powder X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray analysis, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, and elemental mapping analyses. The effects of the adsorption-influencing parameters, including contact time, solution pH, and co-existing cations on the maximum adsorption capacity of Pb²⁺ onto the prepared composite material were investigated. Moreover, the adsorption of Pb²⁺ ions could be eliminated with rapid adsorption kinetics using the water-stable La-MOF@x%PANI composite. The as-synthesized La-MOF@50%PANI exhibited excellent adsorption performance toward Pb²⁺ ions with an extraordinary adsorption capacity of 185.19 mg/g at pH 6. The Pb²⁺ adsorption onto the La-MOF@x%PANI composite follows the pseudo-second-order kinetics and fits well with the Langmuir isotherm model, indicating the Pb²⁺ adsorption depended on the solution pH as the adsorption mechanism was mainly governed by the electrostatic attraction. Notably, La-MOF@x%PANI composite possesses outstanding regeneration ability and stability after up to four successive cycles. The satisfactory findings reflect that the La-MOF@50%PANI hybrid composite holds a great promise for remediating Pb²⁺ ions from aqueous environments.

Electrochemical sensing system for the analysis of emerging contaminants in aquatic environment: A review

This survey distinguishes understudied spaces of arising impurity research in wastewaters and the habitat, and suggests bearing for future checking. Thinking about the impeding effect of toxins on human wellbeing and biological system, their discovery in various media including water is fundamental. This review sums up and assesses the latest advances in the electrochemical detecting of emerging contaminants (ECs). This survey is expected to add to the advancement in electrochemical applications towards the ECs. Different electrochemical insightful procedures like Amperometry, Voltammetry has been examined in this overview. The improvement of cutting edge nanomaterial-based electrochemical sensors and biosensors for the discovery of drug compounds has accumulated monstrous consideration because of their benefits, like high affectability and selectivity, continuous observing, and convenience has been reviewed in this survey. This survey likewise features the diverse electrochemical treatment procedures accessible for the removal of ECs.

Microplastic-associated pathogens and antimicrobial resistance in environment

The ubiquitous use of microplastics and their release into the environment especially the water bodies by anthropogenic/industrial activities are the major resources for microplastic contamination. The widespread and often injudicious use of antimicrobial drugs or antibiotics in various sectors including human health and hygiene, agriculture, animal husbandry and food industries are leading to the release of antibiotics into the wastewater/sewage and other water bodies, particularly in urban setups and thus leads to the antimicrobial resistance (AMR) in the microbes. Microplastics are emerging as the hubs as well as effective carriers of these microbial pathogens beside their AMR-genes (ARGs) in marine, freshwater, sewage/wastewater, and urban river ecosystems. These drug resistant bacteria interact with microplastics forming synthetic plastispheres, the ideal niche for biofilm formations which in turn facilitates the transfer of ARGs via horizontal gene transfer and further escalates the occurrence and levels of AMR. Microplastic-associated AMR is an emerging threat for human health and healthcare besides being a challenge for the research community for effective management/address of this menace. In this review, we encompass the increasing prevalence of microplastics in environment, emphasizing mainly on water environments, how they act as centers and vectors of microbial pathogens with their associated bacterial assemblage compositions and ultimately lead to AMR. It further discusses the mechanistic insights on how microplastics act as hosts of biofilms (creating the plastisphere). We have also presented the modern toolbox used for microplastic-biofilm analyses. A review on potential strategies for addressing microplastic-associated AMR is given with recent success stories, challenges and future prospects.

Cerium-polysulfide redox flow battery with possible high energy density enabled by MFI-Zeolite membrane working with acid-base electrolytes

A pH change can enable high-energy-density RFB (redox flow battery) in an aqueous medium. Nevertheless, a membrane to prevent the ion crossover is needed. This study adopted cerium and polysulfide in an acid-base combined electrolyte with an MFI-Zeolite membrane as a separator. The increased potential with pH change is described by the OCP (open circuit potential) difference, which varies by 0.8 V for the combination of acid-acid and acid-base electrolyte. A decrease of 350 mV at the redox peak potential of Ce³⁺/Ce⁴⁺ and a 10 mV negative potential shift for S₄^2-/2S₂^2- highlights the pH effect between the combination of acid-acid and acid-base electrolyte indicates the influence of pH leading in half-cell of anodic than the opposite cathodic side. The UV-visible spectral analysis for Ce³⁺ and S₄^2- ions displacement shows that cerium and sulfur ions do not migrate to each other half-cell through an MFI-Zeolite membrane. As a result, the current efficiency of 94%, voltage, and energy efficiency of 40%-43% were attained at a current density of 10 mA cm^-2. Moreover, the acid-base composition of the Ce/S system showed an energy density of 378.3 Wh l ^-1.

Enhanced sustainable electro-generation of a Ni (I) homogeneous electro-catalyst at a silver solid amalgam electrode for the continuous degradation of N2O, NO, DCM, and CB pollutants

This paper reports the sustainable and enhanced generation of a Ni(I) active electro-catalyst using AgSAE as a cathode material for the sustainable degradation of N₂O, NO, dichloromethane (DCM), and chlorobenzene (CB) by electroscrubbing in a series operation. The AgSAE electrode showed 1.66 times higher Ni(I) formation than the Ag metal electrode. The AgSAE achieved 20% ± 2% Ni(I) generation in a highly concentrated alkaline medium, whereas Ag metal only achieved 12% ± 2% Ni(I) generation at the same current density. Electrochemical impedance spectroscopy and voltammetric studies determined that the kinetics of the charge-transfer reaction was also preferential at the AgSAE, with the cathodic peak at -1.26 V vs. Ag/AgCl confirming Ni(I) formation. Initially, the change in the oxygen reduction potential and reduction efficiency of Ni(I) confirmed the removal of N₂O, NO, DCM and CB. In addition, the gas Fourier transform infrared (FTIR) spectrum revealed 99.8% removal efficiency of toxic pollutants. Therefore, the regeneration of Ni(I) confirmed the sustainable removal of toxic pollutants. Furthermore, the FTIR spectra revealed the formation of NH₃ during the reduction of N₂O and NO. On the other hand, DCM and CB were reduced to benzene derivatives in the solution phase. In addition, a plausible reduction mechanism was derived. As a result, the AgSAE cathode exhibited two-fold higher removal efficiency of N₂O, NO, DCM, and CB than the previously reported electrodes.

Facile fabrication of (2D/2D) MoS2@MIL-88(Fe) interface-driven catalyst for efficient degradation of organic pollutants under visible light irradiation

The present investigation describes the photocatalytic degradation of methylene blue (MB) and rhodamine-B (RhB) using molybdenum disulfide (MoS₂) anchored metal-organic frameworks (MOFs) under visible light irradiation. Herein, MIL-88(Fe) was successfully modified with MoS₂ to yield a novel heterogeneous MoS₂@MIL-88(Fe) hybrid composite. The prepared catalyst enhances the superior photocatalytic activity than the pristine form of MoS₂ and MIL-88(Fe) framework. The physico-chemical properties of the prepared catalyst were analytically investigated and the results exhibit greater photocatalytic efficiency towards the chosen dyes, with an optical band gap of 2.75 eV. The MoS₂ and MIL-88(Fe) framework could act as efficient oxidation and reduction sites in the as-synthesized MoS₂@MIL-88(Fe) composite, and generated the non-toxic by-products such as hydroxyl ^(•OH), and superoxide species ^(•O₂^-) for the mineralization of MB and RhB dyes. The degradation kinetics showed that the dye system followed a pseudo-first-order model which is well supported by the Langmuir-Hinshelwood mechanism. Moreover, the reusability studies showed excellent photocatalytic activity after five cycles. Finally, the photocatalytic degradation mechanism of MB and RhB dyes was suggested.

Production and characterization of biodegradable polyhydroxybutyrate by Micrococcus luteus isolated from marine environment

Marine microorganisms are reported to produce polyhydroxybutyrate (PHB) that has wide range of medical and industrial applications with the advantage of biodegradability. PHBs are synthesized as an energy and carbon storage element under metabolic pressure. The scope of this work is enhancing PHB production using marine microbial isolate, Micrococcus luteus by selectively optimizing various growth conditions such as different media components and growth parameters that influence the cell growth and PHB production were sampled. Micrococcus luteus produced 7.54 g/L of PHB utilizing glucose as a carbon source and ammonium sulphate as a nitrogen source with maximum efficiency. The same optimized operational conditions were further employed in batch fermentation over a time span of 72 h. Interestingly higher cell dry weight of 21.52 g/L with PHB yield of 12.18 g/L and 56.59% polymer content was observed in batch fermentation studies at 64 h. The chemical nature of the extracted polymer was validated with physio-chemical experiments and was at par with the commercially available PHB. This study will spotlight M. luteus as a potential source for large-scale industrial production of PHB with reducing environmental pollutions.

Adsorption characteristics of magnetic nanoparticles coated mixed fungal biomass for toxic Cr(VI) ions in aquatic environment

In this research, the adsorptive removal of Cr(VI) ions from the aquatic environment have been studied using newly synthesized magnetic nanoparticles coated mixed fungal biomass (MNP-FB). Two fungal biomass such as Aspergillus fumigatus and Aspergillus niger were isolated, screened, and utilized as a precursor for making an adsorbent. Molecular characterization of isolated fungal species was recognized using 18S rRNA sequencing. The characterization studies of the MNP-FB were evaluated using Fourier Transform Infrared Spectrophotometer (FTIR) and Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analyses. Optimization studies were studied to check the effect of different operating variables such as pH (2.0-9.0), equilibrium time (10-90 min), MNP-FB dosage (0.1-1.0 g/L), temperature (30-60 °C) and concentration of Cr(VI) ions (50-500 mg/L). Additionally, Freundlich isotherm model fits well for the adsorption of Cr(VI) ion using MNP-FB. The adsorption kinetics was interpreted well by Pseudo-first order model. The thermodynamic study concluded that Cr(VI) ions removal by MNP-FB was exothermic and appreciative at low temperatures. The monolayer adsorption efficiency of MNP-FB for Cr(VI) ions was measured as 249.9 mg/g. The current results reveal that MNP-FB has considered being a proficient and economically suitable material for the Cr(VI) ions removal from the water environment.

Investigation of magnetic silica nanocomposite immobilized Pseudomonas fluorescens as a biosorbent for the effective sequestration of Rhodamine B from aqueous systems

In the current research work, a novel eco-friendly Fe₃O₄@SiO₂ nanocomposite immobilized with Pseudomonas fluorescens biomass in calcium alginate beads (MSAB) was used as biosorbent for the elimination of hazardous Rhodamine B dye from aqueous system. The FTIR, XRD and SEM results showed that the MSAB possessed excellent surface properties for the effective sequestration of Rhodamine B. The batch adsorption results concluded that the adsorption of Rhodamine B using MSAB is highly influenced by the parameters such as pH, adsorbent dosage, initial dye concentration and contact time. The equilibrium and kinetics data get best fitted in the Freundlich isotherm and Pseudo first order kinetics for the studied adsorption system. The Langmuir monolayer adsorption capacity was found to be 229.6 mg/g. The thermodynamic studies showed that the adsorption was spontaneous, feasible and exothermic in nature. The adsorption mechanisms are understood using the Intraparticle diffusion and Boyd model. Thus, this Magnetic silica alginate beads (MSAB) containing dead biomass of Pseudomonas fluorescens is considered to be an ideal biosorbent which can be used as an effective tool in treating the industrial dye wastewater treatment.

Extraction of microplastics from commonly used sea salts in India and their toxicological evaluation

Microplastics (MPs) are one of the marine debris, accumulated in the ocean as a result of the successive breakdown of a large piece of plastics over several years. MPs are about less than 5 mM, have a detrimental impact on marine organisms/products (seafood/sea salts) and therefore they are considered as a global environmental pollutant. The occurrence and impact of MPs in commercial sea salts that are consumed by humans are not well studied so far. In the present study, we attempted to characterize and evaluate the in vitro toxicity of isolated MPs. Here, we have used ten brands of commercial sea salts of different origins for the identification and characterization of MPs. The average abundance of MPs in all commercial brands is < 700 MP/kg and the particle size range between 5.2 mM and 3.8 μM. The most common types of MPs were identified as fragments, fibers, and pellets. By Fourier-Transform infrared spectroscopy (FT-IR), it was found that the MPs in abundance were made of cellophane (CP), polystyrene (PR), polyamide (PA) and polyarylether (PAR). Further, in vitro toxicity assessment revealed that HEK-293 cells get detached upon treatment with MPs (MIC-75 μg mL^-1) Consequently, the AO/EB dual staining confirmed that the induction and rate of apoptosis were comparatively higher in microplastic treated HEK-293 cells. Taken together, the MPs identified are the origin of anthropogenic derivatives and they exert a lethal effect on human cells, which might be associated with health risk complications in human beings.

Non-toxic nano approach for wastewater treatment using Chlorella vulgaris exopolysaccharides immobilized in iron-magnetic nanoparticles

The current study, novel magnetic nano-composite particles (Fe₃O₄@EPS) were successfully synthesized via the co-precipitation of iron (III) chloride and iron (II) sulfate (Fe₃O₄ nanoparticles) with exopolysaccharides (EPS) derived from the microalga Chlorella vulgaris. The physico-chemical nature of the Fe₃O₄@EPS was investigated in depth. Transmission electron microscopy (TEM) results estimated the core-shell nature of Fe₃O₄@EPS aggregated inside the indistinctly layered EPS matrix to be 10-20 nm in size. Scanning electron microscopy-based energy dispersive spectral analysis indicated that elemental Fe was successfully loaded on to the EPS polymeric ion-exchanger at a rate of 63.3% by weight. FT-IR results demonstrated that Fe₃O₄ nanoparticles were successfully modified by the functional groups present in EPS. Fe₃O₄@EPS showed a highly magnetic nature at 5.0 emu/g. The XPS survey spectrum, which showed two major peaks at 724.1 and 710.2 eV revealed the elemental composition and electronic structure of Fe₃O₄ nanoparticles and Fe₃O₄@EPS. Furthermore, nutrient removal from wastewater was studied. Under optimum conditions (3.5 g/L of Fe₃O₄@EPS, pH 7.0 and 13 h of incubation) 91% of PO₄^3- and 85% of NH₄⁺were effectively eliminated. These findings demonstrate the potential of Fe₃O₄@EPS for removing PO₄^3- and NH₄⁺ in wastewater treatment plants.

Rapid biodegradation of chlorpyrifos by plant growth-promoting psychrophilic Shewanella sp. BT05: An eco-friendly approach to clean up pesticide-contaminated environment

The present study explores the rapid chlopyrifos (CPs) biodegradation potential of plant growth promoting (PGP) psychrophilic bacteria isolated from brackish water by enrichment culture technique. Based on biochemical tests and 16 S rDNA sequencing the isolate was identified as Shewanella sp. The isolate Shewanella BT05 showed significant growth rate in various concentrations of (10-50 mg/L) CPs. The isolate produced plant growth promoting factors, IAA (20.8 ± 1.2 and 15.4 ± 1.0 μg/mL) and siderophores (60.67 ± 1.2 and 57.5 ± 0.9%) in the absence and presence of CPs. Further, the isolate BT05 solublized phosphate (16.5 ± 1.0 and 12.0 ± 1.0 mm in size respectively), and produce hydrogen cyanide (excellent and moderate) in the presence and absence of CPs. The isolate BT05 degraded 94.3, 91.8, 87.9, 82.6, and 80.5% of CPs at 10, 20, 30, 40, and 50 mg/L, respectively, within 24 h. Further, the media conditions were optimized for enhanced CPs removal and observed 93% removal in the presence of 3.5% glucose in pH 7.0 at 32.5 °C. Fourier-transform infrared spectroscopy and high-performance liquid chromatography results indicated the role for Shewanella BT05 in the biomineralization of CPs. The results suggested the isolate BT05 could be used for CPs removal as well as PGP activity in contaminated soil.

Effect of citric acid and vermi-wash on growth and metal accumulation of Sorghum bicolor cultivated in lead and nickel contaminated soil

The aim of the present study is to assess the influence of vermi-wash (VW) and citric acid (CA) on Sorghum bicolor growth and phytoaccumulation of lead (Pb) and nickel (Ni) contaminated soil. The biomass of the S. bicolor has been enhanced by the addition of VW (24 and 26%) and CA (11 and 9%) in Pb and Ni contaminated soil, respectively. The VW treatment showed enhanced shoot and root lengths and chlorophyll concentrations compared to CA. The shoot anatomic structure showed an accumulation of Pb and Ni were positively impacted by the amendment of VW and CA. In addition, VW treatment showed enhanced antioxidant enzymes activity (140, 125 and 152 U/mg of CAT, SOD and POD). Further, the plants grown in Pb contaminated soil treated with VW showed enhanced Rubisco activity of 1.49 U/ml, whereas, CA treatment showed 1.23 U/ml of Rubisco. It has been observed that the VW showed as a potential chelator as well as plant beneficial formulation for the enhanced phyto-remediation of Pb and Ni.

Significance of allochthonous brackish water Halomonas sp. on biodegradation of low and high molecular weight polycyclic aromatic hydrocarbons

The present study is aimed to isolate and identify polycyclic aromatic hydrocarbons (PAHs) degrading bacteria from brackish water and to assess the biodegradation efficiency against low and high molecular weight PAHs. Among 15 isolates, the isolate designated as RM effectively degraded 100 mg/L of phenanthrene (Phe) (67.0%), pyrene (Pyr) (63.0%), naphthalene (NaP) (60.0%), and benzo [a]pyrene (BaP) (58.0%) after 7 days of incubation. Carbon sources, pH, and salinity of the culture medium were optimized to enhance the growth and PAHs biodegradation of the isolate RM. Sucrose was found to be an excellent carbon source to enhance PAHs biodegradation (Phe, 75.0; Pyr, 68.5; NaP, 62.5; and BaP, 59.5%). Furthermore, the isolate showed enhanced degradation at pH 7.0 and 4% salinity. The isolate RM was identified as Halomonas sp. based on partial 16S rDNA gene sequence analysis. The results indicated that the isolate RM (i.e., Halomonas sp.) has the potential to be used in remediation of oil spills in the marine ecosystem.

Production and purification of laccase by Bacillus sp. using millet husks and its pesticide degradation application

Lignocellulosic agricultural bi-products, pearl millet (PM) and finger millet (FM) husks, were used for the production of laccase using Bacillus sp. PS under solid-state fermentation (SSF). Abiotic variables such as substrate (PM, FM) concentration (1-5%), incubation time (24-96 h) and pH (5-10) were optimized using Response surface methodology (RSM) to maximize the laccase production. The predicted model showed maximum laccase activity of 402 U/mL appearing after 96 h of incubation with PM 2.0 g/L and FM 1.5 g/L at pH 7.0. Single protein band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) confirmed homogeneity of the laccase with a molecular weight of 63-75 kDa. The partially purified laccase effectively degraded the pesticides (Tricel, 71.8 ± 3.5 and Phoskill 77.3 ± 3.4%) within 5 days of incubation (40 °C) in pH 7.0. The pesticide degradation was further confirmed by high-performance liquid chromatography (HPLC) and the chromatograms showed the single dominant peaks at retention time 2.482 (tricel) and 2.608 (phoskill) min, respectively. Pesticide-degrading laccase was produced by Bacillus sp. PS under SSF reveals the utilization of low-cost bi-substrates for enhanced laccase production.

In-vitro bio-mineralization of arsenic and lead from aqueous solution and soil by wood rot fungus, Trichoderma sp

In the present study, we investigated the role of calcite, i.e., microbiologically-induced precipitate by ureolytic Trichoderma sp. MG, in remediation of soils contaminated with arsenic (As) and lead (Pb). The fungus tolerates high concentrations of As (500 mg/L) and Pb (650 mg/L). The effects of three factors, i.e., urea concentration, CaCl₂ concentration and pH, on urease production and bio-mineralization of As and Pb were investigated using Box-Behnken design. The maximum urease production (920 U/mL) and metal removal efficiency (68% and 59% for Pb and AS, respectively) were observed in the medium containing urea of 300 mM and CaCl₂ of 75 mM at pH 9.0. Fourier transform infrared spectroscopy result revealed the formation of metal carbonates by the isolate MG. Sequential extraction of metals revealed that the carbonate fractions of As and Pb were increased to 46.4% and 42.4% in bioremediated soil, whereas in control they were 35.5% and 32.5%, respectively. The X-ray powder diffraction result further confirmed the role of calcite precipitate in bioremediation of As- and Pb-contaminated soils. The results points out that the microbiologically-induced calcite precipitation is a feasible, eco-friendly technology for the bioremediation of As- and Pb-contaminated sites.

Myco-phytoremediation of arsenic- and lead-contaminated soils by Helianthus annuus and wood rot fungi, Trichoderma sp. isolated from decayed wood

In the present study, Helianthus annuus grown in arsenic- (As) and lead- (Pb) contaminated soil were treated with plant-growth promoting fungi Trichoderma sp. MG isolated from decayed wood and assessed for their phytoremediation efficiency. The isolate MG exhibited a high tolerance to As (650mg/L) and Pb (500mg/L), and could remove > 70% of metals in aqueous solution with an initial concentration of 100mg/L each. In addition, the isolate MG was screened for plant-growth-promoting factors such as siderophores, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, indole acetic acid (IAA) synthesis, and phosphate solubilisation. Phytoremediation studies indicated that treatment of H. annuus with the isolate MG had the maximum metal-accumulation in shoots (As; 67%, Pb; 59%). Furthermore, a significant increase in the soil extracellular enzyme-activities was observed in myco-phytoremediated soils. The activities of phosphatase (35 U/g dry soil), dehydrogenase (41mg TPF/g soil), cellulase (37.2mg glucose/g/2h), urease (55.4mgN/g soil/2h), amylase (49.3mg glucose/g/2h) and invertase (45.3mg glucose/g/2h) significantly increased by 12%, 14%, 12%, 22%, 19% and 14% in As contaminated soil, respectively. Similarly, the activities of phosphatase (31.4U/g dry soil), dehydrogenase (39.3mg TPF/g soil), cellulase (37.1mg glucose/g/2h), urease (49.8mgN/g soil/2h), amylase (46.3mg glucose/g/2h), and invertase (42.1mg glucose/g/2h) significantly increased by 11%, 15%, 11%, 18%, 20% and 14% in Pb contaminated soil, respectively. Obtained results indicate that the isolate MG could be a potential strain for myco-phytoremediation of As and Pb contaminated soil.

Process optimization of biogas energy production from cow dung with alkali pre-treated coffee pulp

Biogas production from cow dung with co-substrate agricultural waste is one of the most demanding technologies for generating energy in a sustainable approach considering eco-friendly. In the present study, coffee pulp (CP) was pre-treated with 1% NaOH and combined with various proportions of cow dung (CD) to explore its biogas producing potentiality. The optimization of the process was studied using Response surface methodology. Statistics based on 3-D plots were generated to evaluate the changes in the response surface and to understand the relationship between the biogas yield and other parameters. The highest methane production (144 mL/kg) was achieved after 90 h of incubation with 1:3 of CP and CD at 40 °C. Gas chromatography analyzes the chemical compositions of the generated biogas and its post combustion emissions. The chemical composition of the substrates before digestion and after fermentation (biogas spent sludge) were measured in terms of fiber content and the values were noted as, total solids (0.53%), ash content (9.2%), volatile fatty acid (100 mg/L), organic carbon (46%) and a total carbohydrate (179 mg/g). The results of the optimization of biogas production presented in this work found to have significance with the process parameters. The outcome of the study has supported the fact of conventional combustion technology that has to be upgraded to prevent these hazardous emissions into the atmosphere.

Bioremediation of heavy metals using an endophytic bacterium Paenibacillus sp. RM isolated from the roots of Tridax procumbens

The aim of the present study was to assess the bioremediation potential of endophytic bacteria isolated from roots of Tridax procumbens plant. Five bacterial endophytes were isolated and subsequently tested for minimal inhibitory concentration (MIC) against different heavy metals. Amongst the five isolates, strain RM exhibited the highest resistance to copper (750 mg/l), followed by zinc (500 mg/l), lead (450 mg/l), and arsenic (400 mg/l). Phylogenetic analysis of the 16S rDNA sequence suggested that strain RM was a member of genus Paneibacillus. Strain RM also had the capacity to produce secondary metabolites, indole acetic acid, siderophores, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and biosurfactant and solubilize phosphate. The growth kinetics of strain RM was altered slightly in the presence of metal stress. Temperature and pH influenced the metal removal rate. The results suggest that strain RM can survive under the high concentration of heavy metals and has been identified as a potential candidate for application in bioremediation of heavy metals in contaminated environments.

Reduction of hexavalent chromium using Aerva lanata L.: elucidation of reduction mechanism and identification of active principles

The effluent discharge treatment for controlling the environment from non biodegradable metal contaminants using plant extract is an efficient technique. The reduction of hexavalent chromium by abundantly available weed, Aerva lanata L. was investigated using batch equilibrium technique. The variables studied were Cr(VI) concentration, Aerva lanata L. dose, contact time, pH, temperature and agitation speed. Cyclic voltammetry and ICP-MS analysis confirmed the reduction of Cr(VI) to Cr(III). Electrochemical analysis proved that, the chromium has not been degraded and the valency of the chromium has only been changed. ICP-MS analysis shows that 100ng/L of hexavalent chromium was reduced to 97.01ng/L trivalent chromium. These results suggest that components present in the Aerva lanata L. are responsible for the reduction of Cr(VI) to Cr(III). The prime components ferulic acid, kaempherol and β-carboline present in the Aerva lanata L. may be responsible for the reduction of Cr(VI) as evident from LC-MS analysis.