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Petroleum hydrocarbons and their derivatives constitute the leading group of environmental pollutants worldwide. In the present global scenario, petroleum and natural gas production, exploration, petroleum refining, and other anthropogenic activities produce huge amounts of hazardous petroleum wastes that accumulate in the terrestrial and marine environment. Due to their carcinogenic, neurotoxic, and mutagenic characteristics, petroleum pollutants pose severe risks to human health and exert ecotoxicological effects on the ecosystems. To mitigate petroleum hydrocarbons (PHs) contamination, implementing "green technologies" for effective cleanup and restoration of an affected environment is considered as a pragmatic approach. This review provides a comprehensive outline of newly emerging bioremediation technologies, for instance; nanobioremediation, electrokinetic bioremediation, vermiremediation, multifunctional and sustainably implemented on-site applied biotechnologies such as; natural attenuation, biostimulation, bioaugmentation, bioventing, phytoremediation and multi-process hybrid technologies. Additionally, the scope of the effectiveness and limitations of individual technologies in treating the petroleum hydrocarbon polluted sites are also evaluated. [ABSTRACT FROM AUTHOR]

The removal of pollutants, including heavy metals, from the aquatic environment is an urgent problem worldwide. Actively developing nanotechnology areas is becoming increasingly important for solving problems in the field of the remediation of aquatic ecosystems. In particular, methods for removing pollutants using nanoparticles (NPs) are proposed, which raises the question of the effect of a combination of NPs and heavy metals on living organisms. In this work, we investigated the role of CuO-NPs in changing the toxicity of Cd and Pb salts, as well as the bioaccumulation of these elements in a culture of the microalga Desmodesmus communis. It was found that CuO-NPs at concentrations of 10, 100, and 1000 µg L−1 had no effect on the viability of microalgae cells. On the 14th day of the experiment, Cd at a concentration of 1 mg L−1 reduced the viability index by 30% and, when combined with CuO-NPs, by 25%, i.e., CuO-NPs slightly reduced the toxic effect of Cd. At the same time, in this experiment, when CuO-NPs and Cd were used together, the level of oxidative stress increased, including on the first day in mixtures with 1 mg L−1 Cd. Under the influence of Pb, the cell viability index decreased by 70% by the end of the experiment, regardless of the metal concentration. The presence of CuO-NPs slightly reduced the toxicity of Pb in terms of viability and reactive oxygen species (ROS). At the same time, unlike Cd, Pb without NPs caused ROS production on the first day, whereas the addition of CuO-NPs completely detoxified Pb at the beginning and had a dose-dependent effect on mixtures at the end of the experiment. Also, the introduction of CuO-NPs slightly reduced the negative effect of Pb on pigment synthesis. As a molecular mechanism of the observed effects, we prioritized the provocation of oxidative stress by nanoparticles and related gene expression and biochemical reactions of algae cells. Analysis of the effect of CuO-NPs on the Cd and Pb content in microalgae cells showed increased accumulation of heavy metals. Thus, when algae were cultured in an environment with Cd and CuO-NPs, the Cd content per cell increased 4.2 times compared to the variant where cells were cultured only with Cd. In the case of Pb, the increase in its content per one cell increased 6.2 times when microalgae were cultured in an environment containing CuO-NPs. Thus, we found that CuO-NPs reduce the toxic effects of Cd and Pb, as well as significantly enhance the bioaccumulation of these toxic elements in the cells of D. communis microalgae. The results obtained can form the basis of technology for the nanobioremediation of aquatic ecosystems from heavy metals using microalgae. [ABSTRACT FROM AUTHOR]

Arsenic (As)-contaminated soil reduces soil quality and leads to soil degradation, and traditional remediation strategies are expensive or typically produce hazardous by-products that have negative impacts on ecosystems. Therefore, this investigation attempts to assess the impact of As-tolerant bacterial isolates via a bacterial Rhizobim nepotum strain (B1), a bacterial Glutamicibacter halophytocola strain (B2), and MgO-NPs (N) and their combinations on the arsenic content, biological activity, and growth characteristics of maize plants cultivated in highly As-contaminated soil (300 mg As Kg−1). The results indicated that the spectroscopic characterization of MgO-NPs contained functional groups (e.g., Mg-O, OH, and Si-O-Si) and possessed a large surface area. Under As stress, its addition boosted the growth of plants, biomass, and chlorophyll levels while decreasing As uptake. Co-inoculation of R. nepotum and G. halophytocola had the highest significant values for chlorophyll content, soil organic matter (SOM), microbial biomass (MBC), dehydrogenase activity (DHA), and total number of bacteria compared to other treatments, which played an essential role in increasing maize growth. The addition of R. nepotum and G. halophytocola alone or in combination with MgO-NPs significantly decreased As uptake and increased the biological activity and growth characteristics of maize plants cultivated in highly arsenic-contaminated soil. Considering the results of this investigation, the combination of G. halophytocola with MgO-NPs can be used as a nanobioremediation strategy for remediating severely arsenic-contaminated soil and also improving the biological activity and growth parameters of maize plants. [ABSTRACT FROM AUTHOR]

In this study, we delved into cutting-edge strategies for the effective management of wastewater, a critical issue exacerbated by industrial pollution and urban expansion. We introduce the use of carbon-based nanomaterials (CBNs), either alone or functionalized with bacteria, as a novel nanobiotechnological solution for urgent nanobioremediation needs. This technique is notable for its exceptional ability to remove various industrial pollutants, including heavy metals, pesticides, textiles, and dyes, emphasizing the pivotal role of CBNs. The development of bionanocomposites through the integration of CBNs with bacteria represents a significant advancement in enhancing bioremediation efforts. In this study, we assessed the potential health and environmental risks associated with CBN usage while offering an in-depth evaluation of the adsorption mechanisms and factors influencing bioremediation effectiveness. Furthermore, the improved efficiency in treating industrial effluents facilitated by bionanocomposites was investigated, and their alignment with circular economy principles through recyclability is discussed. We aimed to provide, a detailed overview of recent advancements, challenges, and prospects for CBNs and bacterial application in sophisticated wastewater treatment, underscoring their vital importance in promoting the environment. [ABSTRACT FROM AUTHOR]

In this study, we delved into cutting-edge strategies for the effective management of wastewater, a critical issue exacerbated by industrial pollution and urban expansion. We introduce the use of carbon-based nanomaterials (CBNs), either alone or functionalized with bacteria, as a novel nanobiotechnological solution for urgent nanobioremediation needs. This technique is notable for its exceptional ability to remove various industrial pollutants, including heavy metals, pesticides, textiles, and dyes, emphasizing the pivotal role of CBNs. The development of bionanocomposites through the integration of CBNs with bacteria represents a significant advancement in enhancing bioremediation efforts. In this study, we assessed the potential health and environmental risks associated with CBN usage while offering an in-depth evaluation of the adsorption mechanisms and factors influencing bioremediation effectiveness. Furthermore, the improved efficiency in treating industrial effluents facilitated by bionanocomposites was investigated, and their alignment with circular economy principles through recyclability is discussed. We aimed to provide, a detailed overview of recent advancements, challenges, and prospects for CBNs and bacterial application in sophisticated wastewater treatment, underscoring their vital importance in promoting the environment.

The removal of pollutants, including heavy metals, from the aquatic environment is an urgent problem worldwide. Actively developing nanotechnology areas is becoming increasingly important for solving problems in the field of the remediation of aquatic ecosystems. In particular, methods for removing pollutants using nanoparticles (NPs) are proposed, which raises the question of the effect of a combination of NPs and heavy metals on living organisms. In this work, we investigated the role of CuO-NPs in changing the toxicity of Cd and Pb salts, as well as the bioaccumulation of these elements in a culture of the microalga Desmodesmus communis. It was found that CuO-NPs at concentrations of 10, 100, and 1000 µg L−1 had no effect on the viability of microalgae cells. On the 14th day of the experiment, Cd at a concentration of 1 mg L−1 reduced the viability index by 30% and, when combined with CuO-NPs, by 25%, i.e., CuO-NPs slightly reduced the toxic effect of Cd. At the same time, in this experiment, when CuO-NPs and Cd were used together, the level of oxidative stress increased, including on the first day in mixtures with 1 mg L−1 Cd. Under the influence of Pb, the cell viability index decreased by 70% by the end of the experiment, regardless of the metal concentration. The presence of CuO-NPs slightly reduced the toxicity of Pb in terms of viability and reactive oxygen species (ROS). At the same time, unlike Cd, Pb without NPs caused ROS production on the first day, whereas the addition of CuO-NPs completely detoxified Pb at the beginning and had a dose-dependent effect on mixtures at the end of the experiment. Also, the introduction of CuO-NPs slightly reduced the negative effect of Pb on pigment synthesis. As a molecular mechanism of the observed effects, we prioritized the provocation of oxidative stress by nanoparticles and related gene expression and biochemical reactions of algae cells. Analysis of the effect of CuO-NPs on the Cd and Pb content in microalgae cells showed increased accumulation of heavy metals. Thus, when algae were cultured in an environment with Cd and CuO-NPs, the Cd content per cell increased 4.2 times compared to the variant where cells were cultured only with Cd. In the case of Pb, the increase in its content per one cell increased 6.2 times when microalgae were cultured in an environment containing CuO-NPs. Thus, we found that CuO-NPs reduce the toxic effects of Cd and Pb, as well as significantly enhance the bioaccumulation of these toxic elements in the cells of D. communis microalgae. The results obtained can form the basis of technology for the nanobioremediation of aquatic ecosystems from heavy metals using microalgae.

Arsenic (As)-contaminated soil reduces soil quality and leads to soil degradation, and traditional remediation strategies are expensive or typically produce hazardous by-products that have negative impacts on ecosystems. Therefore, this investigation attempts to assess the impact of As-tolerant bacterial isolates via a bacterial Rhizobim nepotum strain (B1), a bacterial Glutamicibacter halophytocola strain (B2), and MgO-NPs (N) and their combinations on the arsenic content, biological activity, and growth characteristics of maize plants cultivated in highly As-contaminated soil (300 mg As Kg−1). The results indicated that the spectroscopic characterization of MgO-NPs contained functional groups (e.g., Mg-O, OH, and Si-O-Si) and possessed a large surface area. Under As stress, its addition boosted the growth of plants, biomass, and chlorophyll levels while decreasing As uptake. Co-inoculation of R. nepotum and G. halophytocola had the highest significant values for chlorophyll content, soil organic matter (SOM), microbial biomass (MBC), dehydrogenase activity (DHA), and total number of bacteria compared to other treatments, which played an essential role in increasing maize growth. The addition of R. nepotum and G. halophytocola alone or in combination with MgO-NPs significantly decreased As uptake and increased the biological activity and growth characteristics of maize plants cultivated in highly arsenic-contaminated soil. Considering the results of this investigation, the combination of G. halophytocola with MgO-NPs can be used as a nanobioremediation strategy for remediating severely arsenic-contaminated soil and also improving the biological activity and growth parameters of maize plants.

Heavy metal pollution has increased alarmingly due largely to industrialization, intensive agricultural practices and other anthropogenic activities. Soil heavy metal contamination is the serious threat to the food security worldwide. Due to non-degradative nature, metals persist for a longer period of time in the environment, can be toxic to human health and environments. Acknowledging the toxicity threat, various physical, chemical and biological detoxification strategies such as soil stabilization, soil excavation, soil washing, thermal desorption, chemical extraction and phytoremediation, have been employed in laboratory and under field conditions to treat metal contamination. Such techniques have not completely been successful due to cost, technical complexity, generation of secondary pollutants and conflicting results. Nanotechnology, a rapidly evolving field, has recently been used to remediate hazardous metals. Nanoparticles due to their unique chemical and physical properties are considered important in toxicity alleviation from contaminated environment. The integrated nanoparticles-bioremediation strategies called nano-bioremediation is other promising option that stimulate microbiome functions to remove harmful contaminants from the polluted area. The reported metal removal efficiency of nanobioremediation varies between 12% with biogenic palladium nanoparticle prepared from Spirulina platensis to 100% with iron oxide nanoparticle of Geobacter sulforeducens for palladium and chromium, respectively. This review provides the recent information available in literature about the role of nanotechnology in the metal amelioration from contaminated soils. Understanding the mechanistic interactions between soil microbiome, nanoparticles and contaminants is of paramount importance to explore the microbes-based nanoremediation strategies in the inexpensive abatement of metal enriched environment vis-à-vis crop optimization in contaminated fields. [ABSTRACT FROM AUTHOR]

Crude petroleum oil spillage is becoming a global concern for environmental pollution and poses a severe threat to flora and fauna. Bioremediation is considered a clean, eco-friendly, and cost-effective process to achieve success among the several technologies adopted to mitigate fossil fuel pollution. However, due to the hydrophobic and recalcitrant nature of the oily components, they are not readily bioavailable to the biological components for the remediation process. In the last decade, nanoparticle-based restoration of oil-contaminated, owing to several attractive properties, has gained significant momentum. Thus, intertwining nano- and bioremediation can lead to a suitable technology termed 'nanobioremediation' expected to nullify bioremediation's drawbacks. Furthermore, artificial intelligence (AI), an advanced and sophisticated technique that utilizes digital brains or software to perform different tasks, may radically transfer the bioremediation process to develop an efficient, faster, robust, and more accurate method for rehabilitating oil-contaminated systems. The present review outlines the critical issues associated with the conventional bioremediation process. It analyses the significance of the nanobioremediation process in combination with AI to overcome such drawbacks of a traditional approach for efficiently remedying crude petroleum oil-contaminated sites. [ABSTRACT FROM AUTHOR]

Industrial effluents carrying dyes are considered a major environmental threat in the present era. Methylene blue (MB) dye is one of the key dyes of the thiazine group of dyes. It is broadly used in medical, textile, and various fields and is well known for its carcinogenicity and methemoglobin nature. Bacterial and other microbes-mediated bioremediation is becoming an emerging and significant section for the treatment of wastewater. Isolated bacteria were used for the bioremediation and nanobioremediation of methylene blue dye under varying conditions and parameters. A comparative study was conducted for the remediation of methylene blue dye using bacterial consortium, potential bacteria (isolated by scale-up method), and potential bacteria within zinc oxide nanoparticles. The decolorizing ability of bacteria was analyzed by UV visible spectrophotometer after stirring and static incubation in different time intervals of the isolates. Growth parameters and environmental parameters which include pH, initial dye concentration, and dose of nanoparticles were optimized with the minimal salt medium. An enzyme assay study was also done to check the effect of dye and nanoparticles on bacterial growth and the mode of action of degradation. The authors found that potential bacteria within ZnO nanoparticles showed enhanced decolorization efficiency (95.46% at pH 8) due to the properties of nanoparticles. On the other hand, the decolorization of MB dye by potential bacteria and the bacterial consortium was about 89.08 and 76.3%, respectively, for a 10-ppm dye concentration. During the enzyme assays study, the highest activity was observed for phenol oxidase, nicotinamide adenine dinucleotide (NADH), 2,6-Dichloroindophenol(DCIP), and laccase for nutrient broth having MB dye, MB dye, and ZnO NPs, while no such change was observed for manganese peroxidase enzyme activity. Nanobioremediation is a promising approach to removing such pollutants from the environment. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have polluted soil and aquatic ecosystems by introducing harmful heavy metals (HMs) such as cadmium, copper, mercury, lead, manganese, nickel, zinc, and others. These HMs lead to serious health conditions in humans like cancer, skin lesions, birth defects, liver and kidney damage, and mental retardation leading to other disabilities. Conventional methods of HM remediation of contaminated soil and water include physical, chemical, biological, and integrated methods. The use of physical and chemical methods, in isolation, has been reduced in practice, owing to their negative impacts, however, work on suitable integrated approaches, and the use of organisms for HM remediation has been in steady progress since past few decades. These approaches have proved to be eco-friendly, cost-effective, and show reduced negative impacts on the environment and biota. However, there is consistent increase in anthropogenic contribution to this problem, so, to keep pace with it, more recently work is in advancement on exploiting the biological system to increase the efficiency of bioremediation, using the latest technologies such as genetic engineering and nanotechnology. This paper provides an overview of the current methods deployed to address this problem; developments made in this field in past few decades, and evokes a research thrust that might lead to novel remediation approaches in the future. [ABSTRACT FROM AUTHOR]

Environmental pollution is serious threat for all living organisms. Nanoparticle synthesis using green approach is a non-toxic, easy and energy saving process. Varieties of species have the unique capability to synthesize commercially useful nanoparticles from various metal salt precursors that can help in environmental remediation. The combination of nanotechnology and bioremediation is known as Nanobioremediation. Researchers have shown that biologically nanoparticles shows great potential in reducing environmental pollution from water and soil by adsorption of pollutants and harmful toxic substances from their environment. These greennanoparticles can converttoxic chemicals into less toxic form. Studies also shown that metal nanoparticles also help in removal of harmful bacteria and fungi from environment which can cause diseases in living system. Green synthesised nanoparticles shows very promising results when it comes to environmental remediation they have been used as dye degrader, Oil degrader, photocatalytic agents, biosensors, heavy metals and persidtent organic particulate (POPs) absorbers etc. This review focus on the current status of different types of biologically synthesised nanoparticles in environmental pollution from different species and future challenges associated with environmental remediation. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs), as persistent organic contaminants, are a major source of concern due to their toxic effect on ecosystems and human health. This study attempted to isolate halotolerant PAHs degrading bacteria from saline oil-contaminated soils. Among the isolates, strain KDI with the highest 16S rRNA gene sequence similarity to Labedella gwakjiensis was able to reduce surface tension (ST) from 65.42 to 26.60 mN m−1 and increase the emulsification index to 81.04%, as a result of significant biosurfactant production. Response Surface Methodology (RSM) analysis was applied to optimize the factors, i.e. PAHs concentration and NaCl concentration as well as to determine the effect of these important variables on PAHs biodegradation. The Carbon Quantum Dots. Iron Oxide (CQDs.Fe3O4) nanoparticles were characterized by several popular analytical techniques, after which the effect of CQD.Fe3O4 nanoparticles on biodegradation was examined. PAHs biodegradation rate and efficiency of strain KDI to degrade PHE in the presence of CQD.Fe3O4 nanoparticles was analyzed by GC. According to the results during biodegradation both the concentration of PAHs and the amount of NaCl were effective. The biodegradation rate significantly increased in the presence of CQD.Fe3O4. The highest biodegradation of PHE occurred in the presence of 0.5 g/L of CQD.Fe3O4 which was 63.63% and 81.77% after 48 and 72 h of incubation. To the best of our knowledge, this is the first report on optimization of PAHs concentration and salinity by RSM and nanobioremediation of PHE using a bacterial strain in the presence of CQD.Fe3O4 nanoparticles. [ABSTRACT FROM AUTHOR]

Dye contaminants in industrial effluents contribute significantly to environmental pollution. Conventional wastewater treatment methods are expensive and energy-consuming. These limitations could be overcome by the use of nanobioremediation processes. The present work was an effort to study decolorization of azo dyes by ZnO nanoparticles (NPs). Rubine GDB (R-GDB) and Congo Red (CR) were the azo dyes selected for the study. The ZnO NPs were successfully synthesized by chemical and biological methods. Chemical synthesis of ZnO NPs was carried out by co-precipitation method; biosynthesis was done using bacteria Bacillus subtilis. The synthesized nanoparticles were characterized by UV–Vis Spectroscopy, SEM, and XRD. The UV spectrophotometer showed peaks in the range of 300–400 nm. SEM pictures indicated the presence of NPs in the size of 100–200 nm. XRD results were analyzed based on the peaks that were seen. EDX analysis showed the presence of Zn particles and oxygen particles majorly. Decolorization efficiency was evaluated by calculating % decolorization by Meyer's method. Chemically synthesized NPs showed maximum % decolorization of the R-GDB (89.55 ± 0.44%) and CR (88.52 ± 0.90%). The biosynthesized NPs showed the least decolorization (R-GDB, 18.46 ± 0.45% and CR, 21.41 ± 1.02%). However, moderate percentages of decolorization of both the azo dyes were observed when a combination of the NPs was used (R-GDB, 36.25 ± 0.22% and CR, 39.47 ± 0.94%). Nanoparticles showed good potential for the decolorization of the azo dyes. With further optimization of the parameters, the present findings show that dye decolorization by chemically synthesized ZnO NPs could be used as a probable nanobioremediation approach to treat wastewaters. [ABSTRACT FROM AUTHOR]

Sustainable agriculture and humanity's civilization rest upon valuable natural resources such as earth and water, which have gone maximal exploitation and have been deteriorated by human activities. Heavy metals are natural components and one of the major pollutants of our environment, with a high atomic number and five times the density of water. The conventional physicochemical treatments for metal removal being cost‐intensive, have naturally paved the way for bioremediation, which is an attractive and economical alternative. Over the last few years, bionanotechnology has emerged as a useful tool in the remediation of heavy metals. The elimination of heavy metals continues to be a burning issue in research, and nanomaterials provide a particular affinity as well as high surface area for heavy metal adsorption. A chemically engineered nanoparticle can be expensive and also requires the use of toxic agents which may be undesirable for the environment. To cut the cost and produce clean, ecofriendly nanoparticles, biogenic synthesis of nanoparticles can be accomplished with the help of different microorganisms as well as plants, which can be further exploited for heavy metal remediation. [ABSTRACT FROM AUTHOR]

Nanotechnology has gained huge importance in the field of environmental clean‐up today. Due to their remarkable and unique properties, it has shown potential application for the remediation of several pesticides and textile dyes. Recently it has shown positive results for the remediation of sodium dodecyl sulfate (SDS). One of the highly exploited surfactants in detergent preparation is anionic surfactants. The SDS selected for the present study is an example of anionic linear alkyl sulfate. It is utilized extensively in industrial washing, which results in the high effluent level of this contaminant and ubiquitously toxic to the environment. The present review is based on the research depicting the adverse effects of SDS in general and possible strategies to minimizing its effects by bacterial degradation which are capable of exploiting the SDS as an only source of carbon. Moreover, it has also highlighted that how nanotechnology can play a role in the remediation of such recalcitrant pesticides. [ABSTRACT FROM AUTHOR]

The textile and leather industry produces large amounts of wastewater that contains high levels of chemicals and other pollutants, incorporated during the processing stages. We evaluated the efficacy of green synthesized iron oxide (α-Fe2O3) and magnesium oxide (MgO) nanoparticles (NPs) for wastewater treatment of crude textile and tannery effluents. Green synthesis of α-Fe2O3-NPs and MgO-NPs was conducted using the newly obtained Aspergillus carbonarious strain D-1. The optimization of the physicochemical parameters for the biosynthesis of NPs, including incubation periods, contact time, pH, temperature, and precursor concentrations, were assessed. The characterization of NPs obtained under optimal conditions was evaluated using UV–visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, dynamic light scattering (DLS), and Fourier Transform Infrared (FT-IR) Spectroscopy. The optimal concentration for efficient textile/tannery wastewater decolorization was determined to be 100 mg NPs after eight hours for α-Fe2O3-NPs and after four hours for MgO-NPs. Under these conditions, chemical oxygen deman (COD), pH value, total dissolved solids (TDS), total suspended solids (TSS), and conductivity were greatly reduced as compared to control for crude textile wastewater. GC–MS analysis of NPs-treated textile wastewater revealed that some major compounds were greatly diminished, bio-transformed, or completely degraded. MgO and α-Fe2O3 NPs exhibited a high capacity to reduce the COD of tannery wastewater by 97.5% and 95.0%, respectively. Hematite NPs exhibited higher removal capacity for TDS, TSS, and conductivity compared to MgO-NPs. MgO and hematite NPs exhibited high capacities to remove Cr, with MgO redcing Cr by 87.06 and hematite NPs reducing Cr by 75.4%. MgO-NPs were more effective than α-Fe2O3-NPs at removing Pb, Ni, and Cd.

Lignin is an important commercially produced polymeric material. It is used extensively in both industrial and agricultural activities. Recently, it has drawn much attention from the scientific community. It is abundantly present in nature and has significant application in the production of biodegradable materials. Its wide usage includes drug delivery, polymers and several forms of emerging lignin nanoparticles. The synthesis of lignin nanoparticles is carried out in a controlled manner. The traditional manufacturing techniques are costly and often toxic and hazardous to the environment. This review article highlights simple, safe, climate-friendly and ecological approaches to the synthesis of lignin nanoparticles. The changeable, complex structure and recalcitrant nature of lignin makes it challenging to degrade. Researchers have discovered a small number of microorganisms that have developed enzymatic and non-enzymatic metabolic pathways to use lignin as a carbon source. These microbes show promising potential for the biodegradation of lignin. The degradation pathways of these microbes are also described, which makes the study of biological synthesis much easier. However, surface modification of lignin nanoparticles is something that is yet to be explored. This review elucidates the recent advances in the biodegradation of lignin in the ecological system. It includes the current approaches, methods for modification, new applications and research for the synthesis of lignin and lignin nanoparticles. Additionally, the intricacy of lignin’s structure, along with its chemical nature, is well-described. This article will help increase the understanding of the utilization of lignin as an economical and alternative-resource material. It will also aid in the minimization of solid waste arising from lignin.

Perylene (PRL), a fivering nuclear polycyclic aromatic hydrocarbon (PAH) has attracted attention because of its toxic properties. This study aimed to evaluate the efficiency of yeast consortium YC02 to remediate PRL in presence of ZnO nanoparticles and produced biosurfactant in the growth medium. Response surface methodology (RSM), 3-level five variables Box-Behnken design (BBD) was employed to optimize the factors viz. pH 7.0, temperature 30ºC, shaking speed 130 rpm, inoculum dosage 3% and zinc oxide nanoparticles (ZnO) concentration 2 g L-1 after a period of 6 days of incubation for the enhanced degradation of PRL (74 ± 0.01%) using yeast consortium. It was well in close agreement with the predicated value obtained by RSM model yield (74 ± 0.8%). Analysis of variance (ANOVA) showed F-value of 58.13, R² of 0.9790, probability of <0.0001 and coefficient of variation of 1.32 % confirmed the validity of the model. Degradation of PRL was assessed using GC-MS and FTIR analysis. Kinetic study demonstrated that PRL degradation fitted first order kinetic model. To the best of our knowledge, this is the first report on process optimization towards nanobioremediation of PRL using yeast consortium in presence of ZnO nanoparticles and produced biosurfactant in medium. [ABSTRACT FROM AUTHOR]

The present study has demystified the first and single step prunosynthesis of the spherical silver nanoparticles (AgNPs) from aqueous fruit extract of angiospermic plant, Prunus cerasifera, which has remarkable fusion of reducing cum stabilizing bioactive components (phenols, anthocyanins, carotenoids, flavonoids, organic acids, tannins and vitamins). Highly stable prunosynthetic AgNPs with 2.04 nm average crystallite size were synthesized in dark and in sunlight at optimized condition of temperature, time and P. cerasifera concentration. Synthesized nanoparticles were characterized through UV-Vis, FTIR, XRD, TGA, SEM and GCMS. Photocatalytic activity of prunosynthetic AgNPs was evaluated for methyl red, erichrome black, methyl blue, bromophenol blue and bromocresol green via UV-Vis. Degradation was achieved (<15 minutes) and expressed as pseudo-first-order kinetics. Prunosynthetic AgNPs demonstrated broad spectrum dose-dependent inhibition (in vitro) in comparison to standard antimicrobial drugs against pathogenic strains X. citri, P. syringae, A. niger, A. flavus, A. fumigatus, A. terreus, P. chrysogenum, F. solani and L. theobromae. Photocatalytic degradation results show the nanobioremediation potential of prunosynthetic AgNPs in indemnifying the persistent environmental pollutants. From the inherently higher inhibition rates for biomimetic prunosynthetic AgNPs, it is envisioned that these can be commercialized as future "green" nanobactericide and nanofungicide at industrial scale economically from nontoxic phytoconstituents. [ABSTRACT FROM AUTHOR]

The elimination of contaminants caused by anthropogenic activities and rapid industrialization can be accomplished using the widely used technology of bioremediation. Recent years have seen significant advancement in our understanding of the bioremediation of coupled polycyclic aromatic hydrocarbon contamination caused by microbial communities including bacteria, algae, fungi, yeast, etc. One of the newest techniques is microbial-based bioremediation because of its greater productivity, high efficiency, and non-toxic approach. Microbes are appealing candidates for bioremediation because they have amazing metabolic capacity to alter most types of organic material and can endure harsh environmental conditions. Microbes have been characterized as extremophiles that can survive in a variety of environmental circumstances, making them the treasure troves for environmental cleanup and the recovery of contaminated soil. In this study, the mechanisms underlying the bioremediation process as well as the current situation of microbial bioremediation of polycyclic aromatic hydrocarbon are briefly described. [Display omitted] • Microbes break down the complex form of various pollutants and their end product is CO 2. • Microbial remediation is an enzymatic oxidation process. • Monooxygenase or Dioxygenase enzymatic oxidation is the initial step in microbial remediation. • Bacterial and fungal enzymes are responsible for the degradation of high molecular weight PAHs. [ABSTRACT FROM AUTHOR]

The demand for new technologies to accelerate the decontamination of contaminated sites and reduce the costs of these technologies is increasingly growing. The use of nanomaterials, particularly iron nanoparticles, as an innovative method to contaminated site remediation has received greater attention recently. However, although several studies have been performed on nanomaterials, little is understood about their behavior in the soil pores, adsorption on mineral particles, and interaction with soil microorganisms. This study aims to present an overview of the application of nanomaterials applied to soil remediation, addressing their toxicity to the soil microorganisms and the feasibility of integration with other remediation technologies, including bioremediation. First, the problem of contaminated sites around the world and the responsibility and need to recover these sites are presented. Next, a brief review on the use of nanoparticle (NPs) for contaminated sites, including their field applications as well as the challenges of using them in field application, is presented. Then, the effects of the presence in NPs on soil microorganisms, either the negative effects (biocide) or the positive effects (biostimulant), are discussed. Finally, we propose the concept of Nanobioremediation (NBR) , aiming to integrate two remediation technologies for effective, efficient and eventually sustainable remediation. It is concluded that the biogeochemistry of the contaminated site can have profound influence on the remediation of NPs, and the interaction of these NPs with the contaminants and microorganisms, depending on the soil conditions. However, ongoing research studies aim to integrate the use of nanotechnology and bioremediation sequentially or concurrently for creating remediation processes more efficient, efficient and sustainable. [ABSTRACT FROM AUTHOR]

Nowadays, contamination due to the organic/inorganic composites has increased promptly due to rising anthropological intrusion which is foremost issue for worldwide food safety and environments. Different physical and chemical approaches have been investigated for the removal of toxic pollutants from the ecosystem. Due to their high costs, ineffective removal methods, toxic material production and large capital requirements have been constrained. Hence it is crucial to develop and achieve environmental sustainability through the use of efficient, environmentally friendly and economically viable approaches. The use of nanoparticles to reduce the contaminants has grown in recent decades. Due to their small size, high reactivity and catalytic activities nanoparticles have been used effectively to remediate the contaminated soil and water. Different microbes such as bacteria, fungi and algal species are also involved in remediation purposes. By immobilizing or stimulating the remediating microbial enzymes, these microbes can act as facilitators in the bioremediation of hazardous substances. Nanoparticles along with microbes have proven to be more efficient than other methods of contaminant removal. Nanobioremediation has enormous potential for large scale environmental clean-up at low cost and with minimal amount of toxic consequences. In this review, we emphasis on the applications of nanoparticles in different sectors and elimination of lethal contaminants such as xenobiotic compounds, synthetic dyes and heavy metals with the help of nanotechnology and microbial inoculants for sustainable development. [Display omitted] • Nanotechnology has applications in a variety of fields. • Nanotechnology is crucial for toxic pollutant removal. • Microbial inoculants with nanoparticles remove pollutants more efficiently. • Nanoparticle-mediated degradation mechanisms in microbes are discussed. [ABSTRACT FROM AUTHOR]

Lignin is an important commercially produced polymeric material. It is used extensively in both industrial and agricultural activities. Recently, it has drawn much attention from the scientific community. It is abundantly present in nature and has significant application in the production of biodegradable materials. Its wide usage includes drug delivery, polymers and several forms of emerging lignin nanoparticles. The synthesis of lignin nanoparticles is carried out in a controlled manner. The traditional manufacturing techniques are costly and often toxic and hazardous to the environment. This review article highlights simple, safe, climate-friendly and ecological approaches to the synthesis of lignin nanoparticles. The changeable, complex structure and recalcitrant nature of lignin makes it challenging to degrade. Researchers have discovered a small number of microorganisms that have developed enzymatic and non-enzymatic metabolic pathways to use lignin as a carbon source. These microbes show promising potential for the biodegradation of lignin. The degradation pathways of these microbes are also described, which makes the study of biological synthesis much easier. However, surface modification of lignin nanoparticles is something that is yet to be explored. This review elucidates the recent advances in the biodegradation of lignin in the ecological system. It includes the current approaches, methods for modification, new applications and research for the synthesis of lignin and lignin nanoparticles. Additionally, the intricacy of lignin's structure, along with its chemical nature, is well-described. This article will help increase the understanding of the utilization of lignin as an economical and alternative-resource material. It will also aid in the minimization of solid waste arising from lignin. [ABSTRACT FROM AUTHOR]

Abiotic and biotic remediation of chlorinated ethenes (CEs) in groundwater from a real contaminated site was studied using biochar-based composites containing nanoscale zero-valent iron (nZVI/BC) and natural resident microbes/specific CE degraders supported by a whey addition. The material represented by the biochar matrix decorated by isolated iron nanoparticles or their aggregates, along with the added whey, was capable of a stepwise dechlorination of CEs. The tested materials (nZVI/BC and BC) were able to decrease the original TCE concentration by 99% in 30 days. Nevertheless, regarding the transformation products, it was clear that biotic as well as abiotic transformation mechanisms were involved in the transformation process when nonchlorinated volatiles (i.e., methane, ethane, ethene, and acetylene) were detected after the application of nZVI/BC and nZVI/BC with whey. The whey addition caused a massive increase in bacterial biomass in the groundwater samples (monitored by 16S rRNA sequencing and qPCR) that corresponded with the transformation of trichloro- and dichloro-CEs, and this process was accompanied by the formation of less chlorinated products. Moreover, the biostimulation step also eliminated the adverse effect caused by nZVI/BC (decrease in microbial biomass after nZVI/BC addition). The nZVI/BC material or its aging products, and probably together with vinyl chloride-respiring bacteria, were able to continue the further reductive dechlorination of dichlorinated CEs into nonhalogenated volatiles. Overall, the results of the present study demonstrate the potential, feasibility, and environmental safety of this nanobioremediation approach. [Display omitted] • Novel nano iron-biochar composite (nZVI/BC) was tested to remediate contaminated groundwater. • NZVI/BC followed by biostimulation transformed chlorinated ethenes (CEs). • CEs were dechlorinated into less toxic nonhalogenated volatiles. • 16S rRNA sequencing revealed development of an organohalide-respiring community. • Living bacterial biofilm was detected on nZVI/BC using fluorescence microscopy. [ABSTRACT FROM AUTHOR]