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Heavy metals are extensively discharged through various anthropogenic activities, resulting in an environmental risk on a global scale. In this case, microorganisms can survive in an extreme heavy metal-contaminated environment via detoxification or resistance, playing a pivotal role in the speciation, bioavailability, and mobility of heavy metals. Therefore, studies on the mechanism for the microbial transformation of heavy metals are of great importance and can provide guidance for heavy metal bioremediation. Current research studies on the microbial transformation of heavy metals mainly focus on the single oxidation, reduction and methylation pathways. However, complex microbial transformation processes and corresponding bioremediation strategies have never been clarified, which may involve the inherent physicochemical properties of heavy metals. To uncover the underlying mechanism, we reclassified heavy metals into three categories based on their biological transformation pathways, namely, metals that can be chelated, reduced or oxidized, and methylated. Firstly, we comprehensively characterized the difference in transmembrane pathways between heavy metal cations and anions. Further, biotransformation based on chelation by low-molecular-weight organic complexes is thoroughly discussed. Moreover, the progress and knowledge gaps in the microbial redox and (de)methylation mechanisms are discussed to establish a connection linking theoretical advancements with solutions to the heavy metal contamination problem. Finally, several efficient bioremediation strategies for heavy metals and the limitations of bioremediation are proposed. This review presents a solid contribution to the design of efficient microbial remediation strategies applied in the real environment. [ABSTRACT FROM AUTHOR]

• Combined with the actual site groundwater characteristics. • Discussed the design of MFCs, including configuration and size, electrode, membranes and separators, contaminants. • Reviewed the progress of research on groundwater removal with MFCs in the last decade. • Considerd the efficiency and practicability of MFCs. Microbial fuel cells (MFCs) have become more prevalent in groundwater remediation due to their capacity for power generation, removal of pollution, ease of assembly, and low secondary contamination. It is currently being evaluated for practical application in an effort to eliminate groundwater pollution. However, a considerable majority of research was conducted in laboratories. But the operational circumstances including anaerobic characteristics, pH, and temperature vary at different sites. In addition, the complexity of contaminants and the positioning of MFCs significantly affect remediation performance. Taking the aforementioned factors into consideration, this review summarizes a bibliography on the application of MFCs for the remediation of groundwater contamination during the last ten decades and assesses the impact of environmental conditions on the treatment performance. The design of the reactor, including configuration, dimensions, electrodes, membranes, separators, and target contaminants are discussed. This review aims to provide practical guidance for the future application of MFCs in groundwater remediation. [Display omitted] [ABSTRACT FROM AUTHOR]

After shale gas well sites are exploited, remediation is essential to restore the ecological environment. Effective bioremediation often has long cycles, so reducing this period is a research focus. To elucidate the intrinsic mechanisms between microorganisms and oil removal and to support the acceleration of bioremediation, gas chromatography–mass spectrometry and high-throughput sequencing technologies were utilized. The oil transformation and microbial response mechanisms during the natural remediation process from August to December at an abandoned shale gas well site in Weiyuan County, Neijiang City, Sichuan Province, were analyzed, revealing the directions of microbial succession. The Results showed that from August to September, the greatest degradation of oil components (C10-C20、C21-C30 alkanes) occurred, with Actinobacteriota, Gemmatimonadota, Proteobacteria, Acidobacteriota, Bacteroidota, and Ascomycota playing major roles. Key contributors to oil degradation included Sphingomonas, Flavisolibacter, Ramlibacter, Mortierella, Fusarium, and Rectifusarium. These microorganisms, along with those such as Chloroflexi, Gemmatimonas, Ellin6067, Cercospora, Sarocladium, Preussia, Calyptrozyma, Staphylotrichum, and Exophiala, which facilitate the cycling of nutrients like carbon, nitrogen, and phosphorus, collectively promote the degradation of oil. Moisture content, electrical conductivity, total nitrogen, total phosphorus, and pH affect the activity of oil-degrading microbes and thus oil degradation. Conversely, microbes alter soil chemistry during degradation, impacting those physicochemical properties. This feedback mechanism influences the activity of other oil-degrading microbes, creating a dynamic interaction network. Ultimately, the microbial community shifts towards populations that aid soil ecosystem restoration. This study reveals microbial succession and its role in oil degradation, offering insights for improving and accelerating bioremediation. [ABSTRACT FROM AUTHOR]

Microbial electrochemical technologies represent innovative approaches to contaminated soil and groundwater remediation and provide a flexible framework for removing organic and inorganic contaminants by integrating electrochemical and biological techniques. To simulate in situ microbial electrochemical treatment of groundwater plumes, this study investigates Cr(VI) reduction within a bioelectrochemical continuous flow (BECF) system equipped with soil‐buried electrodes, comparing it to abiotic and open‐circuit controls. Continuous‐flow systems were tested with two chromium‐contaminated solutions (20–50 mg Cr(VI)/L). Additional nutrients, buffers, or organic substrates were introduced during the tests in the systems. With an initial Cr(VI) concentration of 20 mg/L, 1.00 mg Cr(VI)/(L day) bioelectrochemical removal rate in the BECF system was observed, corresponding to 99.5% removal within nine days. At the end of the test with 50 mg Cr(VI)/L (156 days), the residual Cr(VI) dissolved concentration was two orders of magnitude lower than that in the open circuit control, achieving 99.9% bioelectrochemical removal in the BECF. Bacteria belonging to the orders Solirubrobacteriales, Gaiellales, Bacillales, Gemmatimonadales, and Propionibacteriales characterized the bacterial communities identified in soil samples; differently, Burkholderiales, Mycobacteriales, Cytophagales, Rhizobiales, and Caulobacterales characterized the planktonic bacterial communities. The complexity of the microbial community structure suggests the involvement of different microorganisms and strategies in the bioelectrochemical removal of chromium. In the absence of organic carbon, microbial electrochemical removal of hexavalent chromium was found to be the most efficient way to remove Cr(VI), and it may represent an innovative and sustainable approach for soil and groundwater remediation. Integr Environ Assess Manag 2024;20:2033–2049. © 2024 The Author(s). Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points: The research offers valuable insights that can contribute to advancing microbial electrochemical remediation systems designed to reduce Cr(VI) in water‐saturated soils.There were substantial differences from previously reported studies: acclimatization and/or adaptation and transfer of the electroactive bacterial community to Cr(VI) to a bioelectrochemical continuous flow system, no ion exchange membranes, and no nutrients and/or organic carbon added.The research was conducted to simulate most realistically the real conditions of Cr(VI)‐contaminated aquifers, in terms of solid‐to‐liquid ratio, interactions among soil phases, and physicochemical parameters (pH and electrical conductivity).The outcomes achieved in the system for Cr(VI) reduction in water‐saturated soil can demonstrate the feasibility of employing microbial electrochemical technology for the in situ treatment of contaminated aquifers, with interesting implications for economic and environmental sustainability. [ABSTRACT FROM AUTHOR]

High lead (Pb) levels in agricultural soil and wastewater threaten ecosystems and organism health. Microbial remediation is a cost-effective, efficient, and eco-friendly alternative to traditional physical or chemical methods for Pb remediation. Previous research indicates that micro-organisms employ various strategies to combat Pb pollution, including biosorption, bioprecipitation, biomineralization, and bioaccumulation. This study delves into recent advancements in Pb-remediation techniques utilizing bacteria, fungi, and microalgae, elucidating their detoxification pathways and the factors that influence Pb removal through specific case studies. It investigates how bacteria immobilize Pb by generating nanoparticles that convert dissolved lead (Pb-II) into less harmful forms to mitigate its adverse impacts. Furthermore, the current review explores the molecular-level mechanisms and genetic engineering techniques through which microbes develop resistance to Pb. We outline the challenges and potential avenues for research in microbial remediation of Pbpolluted habitats, exploring the interplay between Pb and micro-organisms and their potential in Pb removal. [ABSTRACT FROM AUTHOR]

• The immobilized bacteria can promote the removal of chlorpyrifos in solution. • The immobilized bacteria can enhance remediation of chlorpyrifos-contaminated soil. • The immobilized bacteria can protect the functional diversity and metabolic activity of the soil microorganism. Chlorpyrifos is a pesticide widely used in agricultural production with a relatively long residual half-life in soil. Addressing the problem of residual chlorpyrifos is of universal concern. In this study, rice hull biochar was used as an immobilized carrier to prepare the immobilized strain H27 for the remediation of chlorpyrifos-contamination soil. Soil microorganisms after remediation were investigated by ecotoxicological methods. The immobilized strain H27 had the highest removal rate of chlorpyrifos when 10% bacterial solution was added to the liquid medium containing 0.075-0.109 mm diameter biochar cultured for 22 hr. This study on the removal of chlorpyrifos by immobilized strain H27 showed that the initial concentration of chlorpyrifos in solution was 25 mg/L, and the removal rate reached 97.4% after 7 days of culture. In the soil, the removal rate of the immobilized bacteria group increased throughout the experiment, which was significantly higher than that of the free bacteria and biochar treatment groups. The Biolog-ECO test, T-RFLP and RT-RCR were used to study the effects of the soil microbial community and nitrogen cycling functional genes during chlorpyrifos degradation. It was found that ICP group had the highest diversity index among the four treatment groups. The microflora of segment containing 114 bp was the dominant bacterial community, and the dominant microflora of the immobilized bacteria group was more evenly distributed. The influence of each treatment group on ammonia-oxidizing bacteria (AOB) was greater than on ammonia-oxidizing archaea (AOA). This study offers a sound scientific basis for the practical application of immobilized bacteria to reduce residual soil pesticides. [Display omitted] [ABSTRACT FROM AUTHOR]

Pesticide use in crops is a severe problem in some countries. Each country has its legislation for use, but they differ in the degree of tolerance for these broadly toxic products. Several synthetic pesticides can cause air, soil, and water pollution, contaminating the human food chain and other living beings. In addition, some of them can accumulate in the environment for an indeterminate amount of time. The agriculture sector must guarantee healthy food with sustainable production using environmentally friendly methods. In this context, biological biopesticides from microbes and plants are a growing green solution for this segment. Several pests attack crops worldwide, including weeds, insects, nematodes, and microorganisms such as fungi, bacteria, and viruses, causing diseases and economic losses. The use of bioproducts from microorganisms, such as microbial biopesticides (MBPs) or microorganisms alone, is a practice and is growing due to the intense research in the world. Mainly, bacteria, fungi, and baculoviruses have been used as sources of biomolecules and secondary metabolites for biopesticide use. Different methods, such as direct soil application, spraying techniques with microorganisms, endotherapy, and seed treatment, are used. Adjuvants like surfactants, protective agents, and carriers improve the system in different formulations. In addition, microorganisms are a tool for the bioremediation of pesticides in the environment. This review summarizes these topics, focusing on the biopesticides of microbial origin. [ABSTRACT FROM AUTHOR]

The global concern for risk control of organic contaminated sites is becoming more and more prominent. Traditional ex situ remediation techniques are costly and damage the site, seriously destroying the soil structure and ecological functions. Therefore, in situ means of combining material injection and microbial remediation have become a potential pathway for the green, economical, and efficient remediation of contaminated sites. In this work, a 200 m2 test block was selected for the coupled injection of slow-release oxygen materials and microbial agents, and long-term monitoring of groundwater was carried out. The results showed that the slow-release materials could release oxygen for a period of 90 days, which provided an oxidizing environment for microorganisms to rapidly degrade BTEX. For the pre-adapted indigenous degradation bacterial agent test group, the degradation degree of BTEX was up to 98% after 40 days of injection. The results of the application on the field scale proved the feasibility of reinforcing biostimulation for remediation of underground organic contamination through the coupled injection of slow-release oxygen materials and microbial agents. The results provided theoretical and technical support for the in situ remediation of petroleum hydrocarbon-contaminated sites. [ABSTRACT FROM AUTHOR]

Chlorimuron-ethyl is currently the primary herbicide used for chemical weed control in a soybean field. In this study, a solid microbial inoculum (corn stalk-white rot fungus (W-1)) was prepared for the remediation of farmland soil contaminated by chlorimuron-ethyl. Firstly, the preparation method of the microbial inoculum was studied. Secondly, the degradation rate of the chlorimuron-ethyl in the ground by the solid microbial inoculum is improved by optimizing the proportion of the protective agent. Then the effects of applying solid microbial inoculum, free bacteria and corn straw on the degradation rate of chlorimuron-ethyl in soil were weighed. Finally, Illumina MiSeq sequencing was used to measure the composition and diversity of bacterial and fungal communities in the ground before and after using microbial inoculum. The degradation rate of chlorimuron-ethyl in soil by solid microbial inoculum was 84.87% after 20 d using corn straw as the support, room temperature drying, 4% Ca3(PO4)2 as the protective drying agent, and 1%(w) dextrin as the ultraviolet protective agent. Inoculation of white rot fungi could significantly affect the community structure of bacteria and fungi in the soil, making the chlorimuron-ethyl degrading communities become the dominant communities and playing an essential role in the degradation of chlorimuron-ethyl. The results showed that using solid microbial inoculum was an effective way to repair farmland soil polluted by chlorimuron-ethyl. [ABSTRACT FROM AUTHOR]

The extensive application of neonicotinoid insecticides (NNIs) has resulted in its worldwide detection in waters, leading to risks to human health and ecology safety. Presently, various remediation techniques for NNIs have been developed. However, the critical reviews concerning the remediation approaches for the elimination of NNIs from water are limited. Considering tremendous efforts have been made in the research topic of NNIs removal recently, this study systematacially reviewed the current advances on NNIs remediation approaches, including adsorption, Fenton, ozonation, photodegradation, sulfate radicals based-advanced oxidation processes (AOPs), electrochemical AOPs, percarbonate-based AOPs, periodate-based AOPs, microbial remediation, and phytoremediation. Moreover, NNIs removal by these methods have been critically discussed, compared, and analyzed. Furthermore, mechanisms of different treatment processes have been summarized in detail. Finally, the challenges and perspectives have been proposed. This study highlights the current progresses on NNIs removal technologies and proposes the future research needs in this area, which will provide support to further researches to halt the NNIs contamination. [ABSTRACT FROM AUTHOR]

Microbial remediation has become the most promising technical means for the remediation of polycyclic aromatic hydrocarbons (PAHs) non-point source contaminated soil due to its low cost of treatment, complete degradation of pollutants, and in-situ remediation. In this study, in order to demonstrate the phenanthrene degrading microbial diversity, phenanthrene was chosen as the representative of PAHs and strains capable of degrading phenanthrene were isolated and screened from the sedimentation sludge and the bottom sludge of oil tank trucks, and high throughput sequencing was used to check the dominant strains with a good degrading effect on phenanthrene. Results showed even more than 50% of phenanthrene was degraded in all samples, the composition of PAH-degrading bacteria was diverse, and different environments constructed different functional microbial groups, which resulted in the microbial adapting to the diversity of the environment. Finally, a series of bacterial species with phenanthrene-degrading functions such as Achromobacter, Pseudomonas, Pseudochelatococcus, Bosea was enriched after nine transferring process. Overall, our study offers value information for the enrichment of functional degrading microbes of phenanthrene or other pollutants that more concern should be paid in not only the degradation rate, but also the diversity variation of microbial community composition. [ABSTRACT FROM AUTHOR]

Bacteria indigenous to oil-contaminated water exhibited diverse metabolic capabilities in degrading various aromatic and monoaromatic hydrocarbons. Out of the 28 bacterial strains isolated from the wastewater, each was cultivated with at least one hydrocarbon, including kerosene, naphthalene, toluene, diesel, or aniline. Among these strains, Pseudomonas putida AD-128 emerged as one of the most effective polyaromatic hydrocarbon (PAH) degraders. Following a 6-day treatment period, strain P. putida AD-128 demonstrated proficiency in degrading various PAHs, including naphthalene, phenanthrene, and fluorine. After 6 days of incubation at 20 °C, the degradation of Naphthalene (NAP) notably increased. Gas Chromatography Mass Spectrometry analysis identified the degraded compounds, including pyruvic acid, salicylaldehyde, D-gluconic acid, and catechol. Optimal NAP degradation was observed at 20 °C and pH 6.0, with increased agitation speed correlating with enhanced bacterial growth and heightened degradation, particularly evident after 6 days at 20 °C. Peptone emerged as the most effective among the four nitrogen supplements (ammonium sulfate, potassium nitrate, beef extract, and peptone), significantly reducing residual naphthalene in the medium. The isolated indigenous bacterium, P. putida AD-128, exhibits robust capabilities in degrading PAHs under optimized conditions, making it a valuable asset for environmental management initiatives. [ABSTRACT FROM AUTHOR]

Removal of environmental contamination such as heavy metals in soil, water and environment is of great importance for human welfare. Hence, the objective of this paper is to comparatively evaluate the removal potentials of heavy metals by cassava peels, parts of pawpaw plant, coconut husk, guinea corn chaff, and pineapple peels from bonny light crude oil polluted soil using appropriate standard methods. Results obtained indicated significantly high levels of heavy metals in the untreated crude oil contaminated soil at weeks 1, 8 and 12. There was a significant (P<0.05) decreasing trend in heavy metal levels in the contaminated soil after treatment with the various agro-residues after the 12-week period. The highest reduction of the heavy metals was observed in the test Group treated with a combination of the agro-residues under study; Ni (46.8%), Pb (61%), Cr (46.3%), Cd (34.1%) and As (49.8%) reduction. The results showed that the agro-residues under study can effectively enhance microbial removal of heavy metals in crude oil polluted soil. [ABSTRACT FROM AUTHOR]

Biochar remediation technology is increasingly being valued due to its economic and environmental advantages in treating heavy metal contaminated soil. In order to comprehensively grasp the research progress in this field, we analyzed the current research status, hotspots, and development directions of biochar passivation remediation of heavy metal contaminated soil based on the core collection database of Web of Science from 2008 to 2022, using bibliometrics and CiteSpace visualization technology. The analysis results indicate that since 2014, research on biochar remediation technology has become a hot topic in the treatment of heavy metal contaminated soil, and the number of literature in this field has grown rapidly. The application scope, mechanism of action, application effect, preparation method, and optimization technology of biochar are the main focus of this field. The selection of iron-modified biochar in the rice-soil system, biochar-based nanocomposites, and the combined application of phytoremediation and biochar are current research hotspots. The interaction mechanism between biochar and soil system, microbial remediation technology based on biochar, potential long-term effects of biochar use, and separation technology between biochar and soil are future research directions in the field of biochar remediation of heavy metal contaminated soil. [ABSTRACT FROM AUTHOR]

Purpose: Manganese (Mn) is crucial in low concentrations but can become toxic in soils and sediments, affecting plants and animals. Understanding how plants inoculated with arbuscular mycorrhizal fungi (AMF) tolerate Mn is crucial for the application of these microorganisms in the remediation of contaminated soils. Despite recognized benefits in various plant species, assessing plant-AMF interaction effectiveness in mitigating Mn toxicity is crucial for undocumented plants. Methods: Acacia mangium Willd. plants were inoculated with an AMF native to a Mn mining area and grown in soil with increasing Mn levels (0, 200, and 400 mg kg−1) to evaluate the effects of inoculation on plant growth and plant-AMF association strategies to reduce Mn toxicity. Results: Inoculation with AMF resulted in beneficial effects, minimizing Mn toxicity and enhancing plant growth, despite reduced mycorrhizal colonization and AMF spore levels in the soil. Non-inoculated plants exposed to 400 mg kg−1 of Mn exhibited significant reductions in shoot dry mass (64.9%), number of leaves (25%), and root length (24%) compared to AMF-inoculated plants. Mn concentration was higher in the roots of AMF-inoculated plants at all Mn levels, indicating a restriction in Mn transport to the shoot, thus minimizing damage and promoting plant growth. Energy-dispersive spectroscopy identified Mn, potassium, phosphorus, iron and calcium in AMF spores, suggesting their protective role against Mn phytotoxicity and adaptability of this species of microorganism under stress conditions. Conclusion: The native AMF inoculation reduces toxicity and improves the growth of A. mangium Willd. under high levels of Mn in the soil. [ABSTRACT FROM AUTHOR]

• S. alfredii may be a phytoremediation material for HCMHMs soil. • Heavy metals migrated to rhizosphere soil and were mainly concentrated in roots and leaves by S. alfredii. • Bacteria increased the abundance of some quorum sensing signaling molecules under HCMHMs stress. • Bacteria promoted the path expression that converts serine to cysteine under HCMHMs stress. Pollution accident of nonferrous metallurgy industry often lead to serious heavy metal pollution of the surrounding soil. Phytoremediation of contaminated soil is an environmental and sustainable technology, and soil native microorganisms in the process of phytoremediation also participate in the remediation of heavy metals. However, the effects of high concentrations of multiple heavy metals (HCMHMs) on plants and native soil microorganisms remain uncertain. Thus, further clarification of the mechanism of phytoremediation of HCMHMs soil by plants and native soil microorganisms is required. Using the plant Sedum alfredii (S. alfredii) to restore HCMHM-contaminated soil, we further explored the mechanism of S. alfredii and native soil microorganisms in the remediation of HCMHM soils. The results showed that (i) S. alfredii can promote heavy metals from non-rhizosphere soil to rhizosphere soil, which is conducive to the effect of plants on heavy metals. In addition, it can also enrich the absorbed heavy metals in its roots and leaves; (ii) native soil bacteria can increase the abundance of signal molecule-synthesizing enzymes, such as trpE, trpG, bjaI, rpfF, ACSL , and yidC , and promote the expression of the pathway that converts serine to cysteine, then synthesize substances to chelate heavy metals. In addition, we speculated that genes such as K19703, K07891, K09711, K19703, K07891, and K09711 in native bacteria may be involved in the stabilization or absorption of heavy metals. The results provide scientific basis for S. alfredii to remediate heavy metals contaminated soils, and confirm the potential of phytoremediation of HCMHM contaminated soil. [ABSTRACT FROM AUTHOR]

Carbendazim (methyl benzimidazol-2-ylcarbamate, CBZ) is a systemic benzimidazole carbamate fungicide and can be used to control a wide range of fungal diseases caused by Ascomycetes, Basidiomycetes and Deuteromycetes. It is widely used in horticulture, forestry, agriculture, preservation and gardening due to its broad spectrum and leads to its accumulation in soil and water environmental systems, which may eventually pose a potential threat to nontarget organisms through the ecological chain. Therefore, the removal of carbendazim residues from the environment is an urgent problem. Currently, a number of physical and chemical treatments are effective in degrading carbendazim. As a green and efficient strategy, microbial technology has the potential to degrade carbendazim into non-toxic and environmentally acceptable metabolites, which in turn can dissipate carbendazim from the contaminated environment. To date, a number of carbendazim-degrading microbes have been isolated and reported, including, but not limited to, Bacillus, Pseudomonas, Rhodococcus, Sphingomonas, and Aeromonas. Notably, the common degradation property shared by all strains was their ability to hydrolyze carbendazim to 2-aminobenzimidazole (2-AB). The complete mineralization of the degradation products is mainly dependent on the cleavage of the imidazole and benzene rings. Additionally, the currently reported genes for carbendazim degradation are MheI and CbmA, which are responsible for breaking the ester and amide bonds, respectively. This paper reviews the toxicity, microbial degradation of carbendazim, and bioremediation techniques for carbendazimcontaminated environments. This not only summarizes and enriches the theoretical basis of microbial degradation of carbendazim, but also provides practical guidance for bioremediation of carbendazim-contaminated residues in the environment. [ABSTRACT FROM AUTHOR]

Introduction: Toxic heavy metal pollution has been considered a major ecosystem pollution source. Unceasing or rare performance of Pb2+ to the surrounding environment causes damage to the kidney, nervous, and liver systems. Microbial remediation has acquired prominence in recent decades due to its high efficiency, environment-friendliness, and cost-effectiveness. Methods: The lead biosorption by Bacillus subtilis was optimized by two successive paradigms, namely, a definitive screening design (DSD) and an artificial neural network (ANN), to maximize the sorption process. Results: Five physicochemical variables showed a significant influence (p < 0.05) on the Pb2+ biosorption with optimal levels of pH 6.1, temperature 30°C, glucose 1.5%, yeast extract 1.7%, and MgSO4.7H2O 0.2, resulting in a 96.12% removal rate. The Pb2+ biosorption mechanism using B. subtilis biomass was investigated by performing several analyses before and after Pb2+ biosorption. The maximum Pb2+ biosorption capacity of B. subtilis was 61.8 mg/g at a 0.3 g biosorbent dose, pH 6.0, temperature 30°C, and contact time 60 min. Langmuir's isotherm and pseudo-second-order model with R² of 0.991 and 0.999 were suitable for the biosorption data, predicting a monolayer adsorption and chemisorption mechanism, respectively. Discussion: The outcome of the present research seems to be a first attempt to apply intelligence paradigms in the optimization of low-cost Pb2+ biosorption using B. subtilis biomass, justifying their promising application for enhancing the removal efficiency of heavy metal ions using biosorbents from contaminated aqueous systems. [ABSTRACT FROM AUTHOR]

The escalating accumulation of toxic wastes and biowastes constitutes a critical environmental crisis that demands immediate and effective solutions. Traditional waste treatment methods, predominantly chemical and physical, are increasingly viewed as unsustainable, burdened by high operational costs and the risk of generating secondary pollutants. Against this backdrop, bioremediation emerges as a crucial and sustainable alternative, utilizing the natural detoxifying capabilities of microorganisms. This review article focuses on the use of fungal and bacterial strategies in bioremediation, emphasizing their vital role in the degradation, stabilization, or detoxification of pollutants. We provide an in-depth analysis of the mechanisms by which fungi and bacteria break down various contaminants, presenting a current snapshot of the field's state of knowledge. The article highlights recent innovative advancements that improve the effectiveness and expand the applicability of bioremediation technologies. Moreover, it discusses the practical challenges of scaling these solutions to meet global environmental needs and suggests directions for future research and implementation. This synthesis not only underscores the significance of microbial bioremediation in addressing pressing environmental problems but also acts as a call to action for continued innovation in the sustainable management of hazardous wastes. [ABSTRACT FROM AUTHOR]

This paper provides an introduction to groundwater PRE technology, in situ bioremediation technology, and in situ chemical oxidation technology. It also presents a summary of the core-shell structure and physical and chemical preparation methods of nZVI. Furthermore, it discusses the mechanism by which nZVI degrades heavy metals, non-metallic inorganic substances, halogenated organics, and antibiotics in groundwater through processes such as adsorption/reduction, precipitation etc. The interaction mechanism between nZVI and microorganism coupling system is described along with an analysis of the promoting and inhibiting effects that nZVI has on microorganisms. Additionally, the research progress on removing groundwater pollutants using coupling systems is discussed. Finally, the future research focus for coupling technologies is proposed. [ABSTRACT FROM AUTHOR]

Combining microbiome science and biointegrated design offers opportunities to help address the intertwined challenges of urban ecosystem degradation and human disease. Biointegrated materials have the potential to combat superbugs and remediate pollution while inoculating landscape materials with microbiota can promote human immunoregulation and biodiverse green infrastructure, contributing to 'probiotic cities'. [ABSTRACT FROM AUTHOR]

In the modern era of human progress and industrialization, various agricultural and industrial activities lead to the accumulation of excessive hazardous substances in the environment. These wastes are continuously being concentrated in agricultural soil or water, thereby affecting and threatening the lives of both flora and fauna. To treat these toxic substances, various physico-chemical practices are performed, which are ultimately associated with the production of other toxic chemicals in the environment. Some of the toxic products formed are recalcitrant and inert which further causes hindrances in the proper removal of contaminants from different pollutant sites. However, various biological approaches are being used nowadays for the remediation of these pollutants from the environment. Microbial bioremediation and phytoremediation represent such environment-friendly approaches that have been employed in the degradation of many of these chemicals. Among the microbes, endophytes are now considered a promising means of the remediation of different pollutants from their natural environments. Therefore, the review focuses on the use of endophytes in the treatment of different kinds of pollutants and highlights the potential of these microbial tools in the removal of heavy metals, plastic, and other contaminants from both terrestrial and aquatic habitats. [ABSTRACT FROM AUTHOR]

Pesticide residue pollution in farmland soil is a key factor affecting the safe production of agricultural products. Microbial degradation is a resourceful, efficient, environmentally friendly, and convenient pesticide residue degradation technology. However, it is not significant effective in the practical field application due to its susceptibility to environmental factors. Therefore, stabilizing and enhancing the field activity of degrading bacteria has become a bottleneck in the industrialization of pesticide residue biodegradation technology. Biofilm is a complex community structure formed by bacteria through the secretion of polysaccharides and proteins and other extracellular polymers, which can surround themselves and adhere to the solid surface. Microorganisms exist in the form of biofilms in soil due to the multi-phase and dispersed characteristics of soil environment. The biofilms plays a positive role in enhancing bacteria's resistance to complex environmental stress, improving the degradation ability of pesticide residues, and maintaining soil health. It overcomes the shortcomings of the traditional free-living bacteria direct-injection remediation technology, such as low efficiency, short persistence period, and insensitivity to low concentration pesticide residues. In recent years, research on bacterial biofilms has been applied to bioremediation of water and soil pollution with significant success. On this basis, this article systematically expounds on the degradation mechanism of bacteria biofilm for pesticide residues in soil, analyzes the advantages and ways of using active bacterial biofilms to promote the soil remediation efficiency of pesticide residue pollutions, and proposes innovative research ideas based on bacterial biofilms to enhance soil resistance to pesticide stress and promote soil health. This article provides reference for improving the environment of the production areas of agricultural products and improving the quality and safety of agricultural products. [ABSTRACT FROM AUTHOR]

The widespread and excessive occurrence of uranium causes serious environmental risks. This review presents several important analytical methods for determining elemental and isotopic levels of uranium in samples, involving inductively coupled plasma mass spectrometry (ICP-MS), Raman spectroscopy, LED fluorimetry, multi-collector ICP-MS (MC-ICP-MS) and high-resolution ICP-MS (HR-ICP-MS). Furthermore, the methods and application of microbial remediation and phytoremediation in uranium contaminated soil are summarised in this review. A comprehensive discussion is also provided on several mitigation techniques that effectively used to remove uranium from water. These remediation techniques include a variety of biochars, nanotechnology and removal using magnesium-iron based hydrotalcite- like complexes. [ABSTRACT FROM AUTHOR]

The present work aimed to produce HAp nanoparticles doped with Zn and Ni in order to analyze the incorporation of these elements in the catalytic and antimicrobial properties of HAp. The samples were obtained by the microwave-assisted hydrothermal method in 30 min at 150 °C. XRD and FTIR results showed that HAp was formed without the presence of secondary phases, and Rietveld refinement indicated a reduction in crystallite size after doping. Nanorod-like morphologies were observed by SEM-FEG with reduction in particle size and increase in specific surface area. Furthermore, the hidden gap at 3.26 eV, photoluminescence indicated that there was a predominance of deep defects and XPS showed the presence of dopants on the HAp surface. The catalytic results in the degradation of methylene blue dye indicated that the zinc-doped sample removed 97.85 % under sunlight, 66.81 % under UV light and 70.64 % under ultrasound. After four cycles of reuse under sunlight, good photocatalytic performance was maintained, and inhibition tests indicated that holes and hydroxyls are the active radicals. Antimicrobial activity tests showed that zinc-doped and co-doped samples were efficient in inhibiting Gram-negative bacteria (Escherichia coli). This work brings a promising alternative application for hydroxyapatite in environmental and microbial remediation. [ABSTRACT FROM AUTHOR]

This paper presents the implementation of an innovative solution based on heterogeneous autonomous vehicles to tackle maritime pollution (in particular, oil spills). This solution is based on native microbial consortia with bioremediation capacity, and the adaptation of air and surface autonomous vehicles for in situ release of autochthonous microorganisms (bioaugmentation) and nutrients (biostimulation). By doing so, these systems can be applied as the first line of the response to pollution incidents from several origins that may occur inside ports, around industrial and extraction facilities, or in the open sea during transport activities in a fast, efficient, and low-cost way. The paper describes the work done in the development of a team of autonomous vehicles able to carry as payload, native organisms to naturally degrade oil spills (avoiding the introduction of additional chemical or biological additives), and the development of a multi-robot framework for efficient oil spill mitigation. Field tests have been performed in Portugal and Spain's harbors, with a simulated oil spill, and the coordinate oil spill task between the autonomous surface vehicle (ASV) ROAZ and the unmanned aerial vehicle (UAV) STORK has been validated. [ABSTRACT FROM AUTHOR]

Heavymetal pollution has become a serious concern across the globe due to their persistent nature, higher toxicity, and recalcitrance. These toxic metals threaten the stability of the environment and the health of all living beings. Heavymetals also enter the human food chain by eating contaminated foods and cause toxic effects on human health. Thus, remediation of HMs polluted soils is mandatory and it needs to be addressed at higher priority. The use of microbes is considered as a promising approach to combat the adverse impacts of HMs. Microbes aided in the restoration of deteriorated environments to their natural condition, with long-term environmental effects. Microbial remediation prevents the leaching and mobilization of HMs and they also make the extraction of HMs simple. Therefore, in this context recent technological advancement allowed to use of bioremediation as an imperative approach to remediate polluted soils. Microbes use different mechanisms including bio-sorption, bioaccumulation, bioleaching, bio-transformation, bio-volatilization and bio-mineralization to mitigate toxic the effects of HMs. Thus, keeping in the view toxic HMs here in this review explores the role of bacteria, fungi and algae in bioremediation of polluted soils. This review also discusses the various approaches that can be used to improve the efficiency of microbes to remediate HMs polluted soils. It also highlights different research gaps that must be solved in future study programs to improve bioremediation efficency. [ABSTRACT FROM AUTHOR]

The bioreduction characteristics and mechanisms of Cr(VI) onto Bacillus cereus RCr enhanced by ferric citrate were investigated. The optimum conditions were initial pH 9, temperature 40 °C, inoculation amount 4%, and glucose 3 g/L, respectively. The addition of 1.5 g/L ferric citrate increased the average reduction rate from 120.43 to 220.61 mg/(L∙h) compared with the control (without ferric citrate). The binding capacity of Cr(III) on the cell surface increased to 21%, in which the precipitates were mainly CrO(OH), Cr2O3, and FeCr2O4. Cell membrane was the main site of reduction, related important functional groups: − COOH, C-H, − NH2, C = C, and P-O. Fe(III) increased the yield of NADH and cytochrome c by approximately 48.51% and 68.63%, which significantly facilitated the electron generation and electron transfer, thus increasing the amount of electrons in the bioreduction of heavy metals by an average of 110%. Among the electrons obtained by Cr(VI), the proportion of indirect reduction mediated by Fe(III)/Fe(II) shuttle was 62% on average, whereas direct reduction mediated by reductase was 38%. These results may provide insights into the bioreduction process by bacteria enhanced by Fe(III) for detoxification of heavy metals with multiple valences, as an important step towards improving microbial remediation. [ABSTRACT FROM AUTHOR]

The present study was proposed with the idea to screen and isolate efficient low-density polyethylene (LDPE) degrading novel bacterial strains from the plastic-contaminated dumping site. The identification of the bacterial isolate was performed with the help of microbiological and molecular characterization approaches. The screening of the best isolate was performed based on its growth in Bushnell-Hass broth supplemented with LDPE sheets as the sole carbon source. The molecular characterization revealed that the isolate WD4 showed a similarity with the Pseudomonas aeruginosa species. A comparative analysis of Pseudomonas aeruginosa WD4 identified in the current study with Pseudomonas putida MTCC 2445 strain was performed. The present study demonstrated that the bacterial isolate showed 9.2% degradation of LDPE films while Pseudomonas putida revealed a 6.5% weight reduction after 100 days of incubation at 37 °C. The end products of the LDPE degradation were analysed using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC–MS). The LDPE degradation products eluted include fatty acids such as octadecanoic, hexadecanoic acid, dodecanal, and octyl palmitoleate, alkanes, and some of the unknown compounds after 100 days of microbial treatment with the isolated strain. The detailed analysis of the by-products generated in the current study indicates their contribution to the biochemical pathway of LDPE degradation. The profound scope lies in the scalability of these bacterial strains at the industrial level to combat the LDPE waste and similar plastic garbage problems, globally. [ABSTRACT FROM AUTHOR]

The remediation of emerging contaminants presents a pressing environmental challenge, necessitating innovative approaches for effective mitigation. This review article delves into the untapped potential of soil microbial communities in the bioremediation of emerging contaminants. Bioremediation, while a promising method, often proves time-consuming and requires a deep comprehension of microbial intricacies for enhancement. Given the challenges presented by the inability to culture many of these microorganisms, conventional methods are inadequate for achieving this goal. While omics-based methods provide an innovative approach to understanding the fundamental aspects, processes, and connections among microorganisms that are essential for improving bioremediation strategies. By exploring the latest advancements in omics technologies, this review aims to shed light on how these approaches can unlock the hidden capabilities of soil microbial communities, paving the way for more efficient and sustainable remediation solutions. [ABSTRACT FROM AUTHOR]

AbstractThe bioremediation capacity of microalgae found in the wastewater channels in Irrigation District 03 (DR03) in Mexico was studied. The study evaluated the effect of pH, aeration, light intensity, and water source on the productivity, culture time, and composition of the microalgal biomass, predominantly made up of Chlorella vulgaris spp. Parameters such as Chemical Oxygen Demand (COD), total solids (TS), and turbidity were monitored to assess the efficiency and bioremediation capacity of the microbial consortium. The yield production of microalgal biomass was measured to evaluate the amount produced per unit volume of treated water. Two culture conditions were assessed: uncontrolled and controlled conditions of aeration and lighting. Under controlled culture conditions, a productivity of 0.031 g L−1 d−1 biomass with 17% lipidic fraction and 37.65% ash content was observed, along with a reduction in COD and turbidity by 57 and 85%, respectively. A biomass productivity of 0.024 g L−1 d−1 was obtained. [ABSTRACT FROM AUTHOR]

Veterinary medications are constantly being used for the diagnosis, treatment, and prevention of diseases in livestock. However, untreated veterinary drug active compounds are interminably discharged into numerous water bodies and terrestrial ecosystems, during production procedures, improper disposal of empty containers, unused medication or animal feed, and treatment procedures. This exhaustive review describes the different pathways through which veterinary medications enter the environment, discussing the role of agricultural practices and improper disposal methods. The detrimental effects of veterinary drug compounds on aquatic and terrestrial ecosystems are elaborated with examples of specific veterinary drugs and their known impacts. This review also aims to detail the mechanisms by which microbes degrade veterinary drug compounds as well as highlighting successful case studies and recent advancements in microbe-based bioremediation. It also elaborates on microbial electrochemical technologies as an eco-friendly solution for removing pharmaceutical pollutants from wastewater. Lastly, we have summarized potential innovations and challenges in implementing bioremediation on a large scale under the section prospects and advancements in this field. [ABSTRACT FROM AUTHOR]

Background: Neonicotinoids are a group of synthetic insecticides that are highly effective and have a wide range of insecticidal activities. This group includes acetamiprid, dinotefuran, clothianidin, imidacloprid, sulfoxaflor, nitenpyram, thiamethoxam, and thiacloprid. They are extensively used worldwide, both in rural and urban environments. However, the widespread use of neonicotinoids has led to their accumulation and biomagnification in the environment due to their long half-life. This has resulted in the emergence of toxicological and hazardous pollutants, posing significant risks to humans and non-target animals. Neonicotinoids are a type of insecticides that bind to neuronal nicotinic acetylcholine receptors (nAChRs). This mechanism allows them to effectively activate insect nAChRs while having minimal impact on vertebrate nAChRs. This reduces the risk of toxicity and makes them safer for non-target species. However, the presence of neonicotinoids in the environment can still increase the risk of toxicity and exposure. Although they have low affinity for mammalian nAChRs, concerns arise due to the abundance, diversity, and widespread presence of these receptors, as well as their various functions. These factors raise concerns about the potential impact of these pesticides on unintended species. Therefore, it is crucial to remove neonicotinoids from the environment in a sustainable and methodical manner. Various techniques can be employed to eliminate neonicotinoid residues in soil and aquatic habitats. These techniques include physiochemical remediation methods such as advanced oxidation processes, adsorption, oxidation, Fenton technology, photocatalysis, and activated persulfate-based oxidation. Additionally, microbial remediation techniques involving bacteria, fungi, and microalgae can also be utilized. This review aims to focus on the scientific foundation, advancements, and key topics related to microbial remediation technologies for neonicotinoids. Proper implementation of bioremediation techniques can significantly reduce the harmful effects of neonicotinoids on the environment and human health. Short conclusion: The main focus of this review is the new studies on the bioremediation of neonicotinoids by bacteria, fungi, and microalgae, and the role of their enzymes. This topic is gaining importance as pesticide bioremediation techniques become increasingly significant. [ABSTRACT FROM AUTHOR]

The present study aimed to develop a system using a combination of enzymatic and microbial degradation techniques for removing phenol from contaminated water. In our prior research, the HRP enzyme extracted from horseradish roots was utilized within a core-shell microcapsule to reduce phenolic shock, serving as a monolayer column. To complete the phenol removal process, a second column containing degrading microorganisms was added to the last column in this research. Phenol-degrading bacteria were isolated from different microbial sources on a phenolic base medium. Additionally, encapsulated calcium peroxide nanoparticles were used to provide dissolved oxygen for the microbial population. Results showed that the both isolated strains, WC1 and CC1, were able to completely remove phenol from the contaminated influent water the range within 5 to 7 days, respectively. Molecular identification showed 99.8% similarity for WC1 isolate to Stenotrophomonas rizophila strain e-p10 and 99.9% similarity for CC1 isolate to Bacillus cereus strain IAM 12,605. The results also indicated that columns using activated sludge as a microbial source had the highest removal rate, with the microbial biofilm completely removing 100% of the 100 mg/L phenol concentration in contaminated influent water after 40 days. Finally, the concurrent use of core-shell microcapsules containing enzymes and capsules containing Stenotrophomonas sp. WC1 strain in two continuous column reactors was able to completely remove phenol from polluted water with a concentration of 500 mg/L for a period of 20 days. The results suggest that a combination of enzymatic and microbial degrading systems can be used as a new system to remove phenol from polluted streams with higher concentrations of phenol by eliminating the shock of phenol on the microbial population. [ABSTRACT FROM AUTHOR]

Heavy metal pollution is a major environmental issue that has a negative impact on soil quality and food security. As a result, heavy metal removal or remediation from hazardous sites has become mandatory. Bioremediation based on microorganisms is a promising method to remediate heavy metal-contaminated areas due to its ecofriendly, cost-effective, and highly efficient characteristics. This study aimed to isolate, identify, and characterize rhizospheric bacteria able to resist, reduce, and detoxify heavy metals [chromium (Cr), nickel (Ni), and aluminum (Al)] from agricultural soil. Two isolates were chosen due to their high level of heavy metal resistance and could serve as potential in situ remediation agents at the site of isolation. On the basis of morphological, cultural, biochemical, and molecular characterization, these two isolates were identified as Pseudomonas aeruginosa (S1) and Bacillus cereus (S2). The results revealed a minimum inhibitory concentrations (MICs) of the three heavy metals studied, ranging from 1000 to 1400 µg/mL for the two bacterial isolates. Atomic absorption spectroscopy analysis was used to evaluate the degrading potential. B. cereus was able to reduce Cr and Al more than P. aeruginosa (42% and 67.78% vs. 38.44% and 58.85, respectively). On the other hand, P. aeruginosa showed a higher capacity to degrade Ni than B. cereus (62.33% and 50.76%, respectively). The findings of the analysis revealed information regarding the use of these heavy metal-resistant bacterial isolates as potential bioremediation agents in contaminated environments. Microbial bioremediation offers sustainable alternatives to the traditional physical or chemical remediation technologies of agricultural land. [ABSTRACT FROM AUTHOR]

In recent years, the increase in pollutants has caused the environment to be exposed to pollution. Heavy metals (HMs) carry irreparable risks due to their accumulation and non-biodegradability. Soil contamination with HMs causes their accumulation in plants and animals and ultimately has irreparable effects on human health. Due to the toxic nature of HMs, very trace amounts of them can cause problems. Improper disposal of waste, sewage, pesticides, automobiles, steelmaking activities, coal mines, and thermal power plants are the main sources of HMs emissions. Rice (Oryza sativa L.) is the staple food of most of the population in many countries. Unfortunately, rice has the ability to accumulate many metals, hence if the rice is contaminated, it can have a negative effect on the health and quality of life of many people. In this study, the contamination of soil and rice with HMs has been investigated. Also, some removal processes (physical, chemical, phytoremediation, and microbial remediation) of HMs from soil have been investigated. [ABSTRACT FROM AUTHOR]

Bioremediation is an ingenious and promising method pertinent for recuperating and removing toxic metals in polluted water and lands. Arsenic (As) contamination is a crucial matter worldwide as its supersaturation is gradually intensifying in our environment because of natural and anthropogenic exertion. Microorganisms have a pivotal role in the bioremediation of various arsenic species. Microorganisms can presumably decrease arsenic by employing genetic engineering. By introducing innovative catabolic pathways with the help of different computational tools or by engineering the prevailing metabolic pathways, the limitations likely to crop up in bioremediation can be suppressed. This review accentuates the significance of microbes for the bioremediation of arsenic, and along with that, it scrutinizes the disadvantages and incapability of native and engineered microbes for bioremediation. In addition, arsenic bioremediation employing genetically modified bacteria is more ecologically friendly. It has fewer health hazards than physiochemical-based methods such as coagulation or filtration sedimentation, electrodialysis or osmosis, chemical precipitations, and adsorptions. [ABSTRACT FROM AUTHOR]

Soil contamination by petroleum, including crude oil from various sources, is increasingly becoming a pressing global environmental concern, necessitating the exploration of innovative and sustainable remediation strategies. The present field-scale study developed a simple, cost-effective microbial remediation process for treating petroleum-contaminated soil. The soil treatment involves adding microbial activators to stimulate indigenous petroleum-degrading microorganisms, thereby enhancing the total petroleum hydrocarbons (TPH) degradation rate. The formulated microbial activator provided a growth-enhancing complex of nitrogen and phosphorus, trace elements, growth factors, biosurfactants, and soil pH regulators. The field trials, involving two 500 m3 soil samples with the initial TPH content of 5.01% and 2.15%, were reduced to 0.41% and 0.02% in 50 days, respectively, reaching the national standard for cultivated land category II. The treatment period was notably shorter than the commonly used composting and bioaugmentation methods (typically from 8 to 12 weeks). The results indicated that the activator could stimulate the functional microorganisms in the soil and reduce the phytotoxicity of the contaminated soil. After 40 days of treatment, the germination rate of rye seeds increased from 20 to 90%, indicating that the microbial activator could be effectively used for rapid on-site remediation of oil-contaminated soils. [ABSTRACT FROM AUTHOR]

Chemical oxidation coupled with microbial remediation has attracted widespread attention for the removal of polycyclic aromatic hydrocarbons (PAHs). Among them, the precise evaluation of the feasible oxidant concentration of PAH-contaminated soil is the key to achieving the goal of soil functional ecological remediation. In this study, phenanthrene (PHE) was used as the target pollutant, and Fe2+-activated persulphate (PS) was used to remediate four types of soils. Linear regression analysis identified the following important factors influencing remediation: PS dosage and soil PHE content for PHE degradation, Fe2+ dosage, hydrolysable nitrogen (HN), and available phosphorus for PS decomposition. A comprehensive model of "soil characteristics-oxidation conditions-remediation effect" with a high predictive accuracy was constructed. Based on model identification, Pseudomonas aeruginosa GZ7, which had high PAHs degrading ability after domestication, was further applied to coupling repair remediation. The results showed that the optimal PS dose was 0.75% (w/w). The response relationship between soil physical, chemical, and biological indicators at the intermediate interface and oxidation conditions was analysed. Coupled remediation effects were clarified using microbial diversity sequencing. The introduction of Pseudomonas aeruginosa GZ7 stimulated the relative abundance of Cohnella, Enterobacter, Paenibacillus, and Bacillus, which can promote material metabolism and energy transformation during remediation. [ABSTRACT FROM AUTHOR]

Background: The escalating concern regarding the environmental impact of plastic waste necessitates the adoption of biodegradable methodologies to curtail its adverse effects. A profound comprehension of the intricate interplay between bacteria and polymers becomes imperative for devising effective solutions to address plastic-induced environmental challenges. Numerous microorganisms have evolved specialized mechanisms for the degradation of plastics, rendering them amenable to application in green chemistry for the elimination of hazardous plastics from the ecosystem. This article offers a comprehensive survey of contemporary microbial bioremediation approaches geared towards augmenting plastic waste management and ameliorating plastic pollution. Emphasis is placed on elucidating the potential of microorganisms in mitigating the deleterious repercussions of plastics on ecosystems and human health, underscoring the significance of advanced strategies in green chemistry for sustainable plastic pollution mitigation. Short conclusion: Current research emphasizes the effectiveness of naturally occurring soil microorganisms, particularly fungi like Aspergillus and bacteria like Bacillus, in breaking down plastics. To harness this potential on a broader scale, optimization of microbial activity conditions and pre-treatment with environmentally beneficial compounds are essential. [ABSTRACT FROM AUTHOR]

[Objective] To explore the remediation effect of bio-organic fertilizer on cadmium-contaminated farmland and ensure the safe production of rice. [Method] Cattle manure bio-organic fertilizer, biochar-based bio-organic fertilizer, soybean bio-organic fertilizer and seaweed bio-organic fertilizer were selected to carry out a two-year field experiment in paddy fields with mild cadmium pollution. Soil physical and chemical properties, soil available Cd, rice growth and yield, and brown rice Cd content were determined. [Result] The field test results showed that the application of bio-organic fertilizer increased soil pH by an average of 0.32, alkali-hydrolyzed nitrogen, available phosphorus, available potassium and organic matter were increased by an average of 9.38%, 15.69%, 10.62% and 11.64%, respectively. The plant height, panicle length, root length, panicle weight, 1000-grain weight and yield of rice were increased by 5.86%, 3.83%, 16.54%, 16.91%, 7.14% and 3.65%, respectively. The available Cd content in soil decreased significantly by 0.10 mg/kg, a decrease of 39.12%, and the Cd content in brown rice decreased significantly by 45.36%. [Conclusion] Bio-organic fertilizer has a significant effect on reducing Cd bioavailability in soil and Cd content in rice grains, and can promote rice growth and improve soil fertility. Among them, carbon-based bio-organic fertilizer has the best effect, which can be used as a technical measure to ensure the safe production of rice in the future. [ABSTRACT FROM AUTHOR]

The global concern over emerging pollutants, characterized by their low concentrations and high toxicity, necessitates effective remediation strategies. Among these pollutants, pharmaceutical and personal care products, pesticides, surfactants, and persistent organic pollutants have gained significant attention. These contaminants are extensively distributed within aquatic ecosystems, posing threats to both human and aquatic physiological systems. Nickel, a valuable metal renowned for its corrosion-resistant properties, is widely utilized in various industrial processes, leading to the generation of nickel-containing waste streams, including batteries, catalysts, wastewater, and electrolyte bleed-off. Contamination of soil, water, or air by these waste materials can have adverse effects on the environment and human health. This review article focuses on the recent advancements in environmental and economic implications associated with the removal of nickel from diverse waste sources. Physicochemical technologies employed for treating different nickel-containing effluents and wastewater are discussed, alongside bioremediation techniques and the underlying mechanisms by which microorganisms facilitate nickel removal. The recovery of nickel from waste materials holds paramount importance not only from an economic standpoint but also to mitigate environmental impacts. [ABSTRACT FROM AUTHOR]

Samarium (Sm) is a rare‐earth element recently included in the list of critical elements due to its vital role in emerging new technologies. With an increasing demand for Sm, microbial bioremediation may provide a cost‐effective and a more ecologically responsible alternative to remove and recover Sm. We capitalized on a previously selected Chlamydomonas reinhardtii strain tolerant to Sm (1.33 × 10−4 M) and acidic pH and carried out settling selection to increase the Sm uptake performance. We observed a rapid response to selection in terms of cellular phenotype. Cellular size decreased and circularity increased in a stepwise manner with every cycle of selection. After four cycles of selection, the derived CSm4 strain was significantly smaller and was capable of sequestrating 41% more Sm per cell (1.7 × 10−05 ± 1.7 × 10−06 ng) and twice as much Sm in terms of wet biomass (4.0 ± 0.4 mg Sm · g−1) compared to the ancestral candidate strain. The majority (~70%) of the Sm was bioaccumulated intracellularly, near acidocalcisomes or autophagic vacuoles as per TEM‐EDX microanalyses. However, Sm analyses suggest a stronger response toward bioabsorption resulting from settling selection. Despite working with Sm and pH‐tolerant strains, we observed an effect on fitness and photosynthesis inhibition when the strains were grown with Sm. Our results clearly show that phenotypic selection, such as settling selection, can significantly enhance Sm uptake. Laboratory selection of microalgae for rare‐earth metal bioaccumulation and sorption can be a promising biotechnological approach. [ABSTRACT FROM AUTHOR]

Heavy metals (HMs) are widely used in various industries. High concentrations of HMs can be severely toxic to plants, animals and humans. Microorganism-based bioremediation has shown significant potential in degrading and detoxifying specific HM contaminants. In this study, we cultivated a range of bacterial strains in liquid and solid nutrient medium containing different concentrations of different HMs to select and analyze bacteria capable of transforming HMs. The bacterial strains most resistant to selected HMs and exhibiting the ability to remove HMs from contaminated soils were identified. Then, the bacterial species capable of utilizing HMs in soil model experiments were selected, and their ability to transform HMs was evaluated. This study has also generated preliminary findings on the use of plants for further removal of HMs from soil after microbial bioremediation. Alcaligenes faecalis, Delftia tsuruhatensis and Stenotrophomonas sp. were selected for their ability to grow in and utilize HM ions at the maximum permissible concentration (MPC) and two times the MPC. Lysinibacillus fusiformis (local microflora) can be used as a universal biotransformation tool for many HM ions. Brevibacillus parabrevis has potential for the removal of lead ions, and Brevibacillus reuszeri and Bacillus safensis have potential for the removal of arsenic ions from the environment. The bacterial species have been selected for bioremediation to remove heavy metal ions from the environment. [ABSTRACT FROM AUTHOR]

In the present work, we have developed for the first time a carbon ultramicroelectrode modified by a molecular imprinted polymer (MIP) for selective determination of 3-methyl-4-nitrophenol (MNP) in aqueous media. The polymeric film based on a non-covalent approach was obtained by electropolymerization of ortho-phenylenediamine in the presence of MNP to generate a template-polymer association on the electrode surface. Cyclic Voltammetry (CV) was used for MIP elaboration, performing 20 cycles in the range from 0 to 0.7 V versus Ag/AgCl/Cl−sat. After removing the template, we obtained a specific MNP recognition site on the modified microelectrode. The surfaces of the modified and unmodified microelectrodes were observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Many parameters influencing the electropolymerization process were optimized. Square Wave Voltammetry (SWV) was used for the quantitative analysis of MNP with the optimized following parameters: frequency 50 Hz, potential amplitude 70 mV, and scan increment 15 mV. The peak current increased linearly with the MNP concentration in the range from 1 to 17 mg L−1, and the limit of detection (LoD) for MNP was calculated to be 0.69 mg L−1. The elaborated UME-MIP was applied to study the bioremediation of MNP in a fungal microbial fuel cell using a ligninolytic fungus Trametes trogii (strain CLBE 55). The obtained results showed a zero-order kinetic with a kinetic constant of 10.5 mg L−1 h−1 at 22 °C and a half-time degradation of 4.5 h under an optimal external resistance of 20,950 Ohm and a power density of 1.2 mW m−3. [ABSTRACT FROM AUTHOR]

Ever since the start of the Industrial Revolution, environmental pollution has significantly increased. The prominent cause of most diseases in humans, animals, and plants is the presence of toxic materials, pollutants, contaminants, and hazardous compounds released by industries. One of the major factors is the presence of heavy metals in the air, water bodies and soil. Heavy metals have biomagnification and bioaccumulation characteristics, making them hazardous for flora and fauna on a large scale. Recently, biological sources such as bacteria, fungi, algae, etc., have been used to bioabsorb these heavy metals. The microbial properties of these cell walls are utilized for effective and low-cost absorption of metals. Bioaugmentation, biosorption and biostimulation are effective strategies for reducing the toxicity of hazardous contaminants in the soil and facilitating bioremediation. The mechanism of biosorption is mainly based on ions and functional groups present in the microbes. Fungal species are advantageous over bacteria as they are easier to handle, cost-effective and, most importantly, non-pathogenic, making them ideal candidates for biosorption. This review provides a comprehensive overview of various microbial strains utilized in bioremediation. Further, the review highlights the application of nanotechnology and metabolic engineering approaches to improve the efficacy of Biosorption, Biostimulation and Bioaugmentation. It provides insights on the role of microbial nanoparticles in bioremediation and prospects in the forte of microbe-assisted bioremediation. [ABSTRACT FROM AUTHOR]

Arsenic ranked 20th in abundance on the earth's crust, poses a threat to all living organisms, and has affected over 30 million people worldwide. While bacteria play a crucial role in detoxifying and modifying arsenic to a harmless form, the complex nature of the biological methods involved in the process makes it difficult to comprehend. The present study followed the PRISMA protocols to search PubMed and evaluated eligible studies up to March 20, 2023, and their references to understand the mechanisms and diversity of arsenic resistance in bacteria. The search yielded 1140 studies, of which 196 were included in the systemic review. According to the studies reviewed, most of the arsenic resistant bacteria were isolated from soil, water, and mining tails, and the highest MIC (minimum inhibitory concentration) for arsenate is 900 mM, while for arsenite, it is 180 mM. Exiguobacterium sp. As-9 exhibited the highest amount of MIC for arsenate (700 mM) and arsenite (180 mM) and can remove 99% of arsenic in less than 20 h. The transfer of arsenic in bacterial cell mainly consists of arsenite and arsenate uptake, using glycerol channel G1pF or aquaporin (AQP) and the phosphate transport system respectively. Bioremediation using bacteria to remove or detoxify arsenic toxicity is a cost-effective, and environment friendly method. The potentials of arsenic resistant microorganisms need to be harnessed to mitigate arsenic pollution in contaminated land and water. [ABSTRACT FROM AUTHOR]

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Salinized soil is an important reserved arable land resource in China. The management and utilization of salinized soil can safeguard the current size of arable land and a stable grain yield. Salt accumulation will lead to the deterioration of soil properties, destroy soil production potential and damage soil ecological functions, which in turn will threaten global water and soil resources and food security, and affect sustainable socio-economic development. Microorganisms are important components of salinized soil. Microbial remediation is an important research tool in improving salinized soil and is key to realizing sustainable development of agriculture and the ecosystem. Knowledge about the impact of salinization on soil properties and measures using microorganisms in remediation of salinized soil has grown over time. However, the mechanisms governing these impacts and the ecological principles for microbial remediation are scarce. Thus, it is imperative to summarize the effects of salinization on soil physical, chemical, and microbial properties, and then review the related mechanisms of halophilic and halotolerant microorganisms in salinized soil remediation via direct and indirect pathways. The stability, persistence, and safety of the microbial remediation effect is also highlighted in this review to further promote the application of microbial remediation in salinized soil. The objective of this review is to provide reference and theoretical support for the improvement and utilization of salinized soil. [ABSTRACT FROM AUTHOR]

The increasing urbanization, industrialization, and modernization of the world have made heavy metal pollution a serious issue. Toxic chemicals found in industrial wastes have made a major contribution to the current disastrous environmental pollution and have impaired the growth and metabolism of living organisms. Excessive metal pollution is the result of various ineffective treatment techniques. Bioremediation of heavy metals with plants and bacteria is simultaneously a cost-effective and environmentally friendly approach. Numerous methods, including biosorption, bioaccumulation, and efflux systems, are accessible for bacteria to mitigate the toxicity of heavy metals. Phytoremediation is a novel and promising way to speed up and enhance the rate of heavy metal detoxification. To deal with the toxicity of heavy metals, plants have a variety of defense mechanisms, including phytoextraction, rhizofiltration, phytostabilization, phytovolatilization, and phytotransformation. This study mainly focuses on the bacteria and plants that uptake and sequester toxic heavy metals and the possibilities for using them in bioremediation. [ABSTRACT FROM AUTHOR]