Search Results (819)

This review provides a critical summary of the biological remediation of heavy metals by leveraging the potential of microbes in soils and water ecosystems, highlighting major research findings and practical obstacles. Heavy metals (HMs) pose a severe threat to environmental health due to their toxicity and persistence, necessitating effective remediation strategies. Biological remediation, especially through microorganisms and enzymatic actions, offers a promising alternative to conventional methods due to its eco-friendly and cost-effective nature. The review discusses various microbes, including bacteria, fungi, and algae known for their metal-binding capacities and transformation abilities. It delves into the mechanisms of bioremediation, such as biosorption, bioaccumulation, and biotransformation, facilitated by microbial enzymes like oxidoreductases and hydrolases that remove or bind the chemical structure of HMs. This paper also explores genetic engineering approaches to enhance microbial efficacy in HMs’ uptake and resistance. Furthermore, the review addresses the significant challenges in scaling bioremediation from a laboratory to the field, such as the complexity of environmental conditions, the presence of mixed contaminants, and the need for system optimization to improve efficiency and sustainability. It also evaluates the current legislative framework governing bioremediation practices, suggesting a need for clearer policies to support the integration of biological methods into mainstream remediation strategies. Conclusively, while microbial and enzymatic remediation presents considerable potential, extensive research is needed to overcome existing hurdles and develop robust, field-applicable systems. This paper calls for a multidisciplinary approach combining microbiology, engineering, and environmental sciences to advance this promising field. Full article

This study comprehensively analysed the scientific production of the extraction, characterisation, and toxicological risk of resistant starches obtained from agro-industrial by-products. Articles indexed in the Scopus database between 2015 and 2025 were analysed. The results showed a progressive increase in publications led by Chinese institutions, the most notable being Jiangnan University. Most of the studies were published in high-impact journals, with the International Journal of Biological Macromolecules standing out, followed by Carbohydrate Polymers and Food Chemistry, all in the first quartile. Most studies focused on extraction methods (physical, chemical, and mechanical) and starch characterisation (morphological, structural, molecular, physicochemical, and functional). Emerging trends are directed towards innovative applications such as functional foods. However, the risks associated with contaminants in reusing agro-industrial by-products have not been adequately explored, showing an important gap in the current scientific literature. In this context, future research should focus on evaluating toxicological risks derived from these processes, considering the presence and behaviour of heavy metals, pesticides, and mycotoxins, as well as the possible migration of chemical compounds generated during extraction. Full article

This review provides a comprehensive overview of the advancements in magnesium-based cementitious materials (MBCMs), including magnesium oxychloride cementitious material (MOC), magnesium oxysulfate cementitious material (MOS), and magnesium phosphate cementitious material (MPC). The hydration processes and products, performance characteristics, and applications in soil stabilization are systematically discussed. Key findings reveal that MOC exhibits rapid strength development and excellent thermal stability, while MOS demonstrates improved water resistance and mechanical properties. MPC is highlighted for its effectiveness in the immobilization of heavy metals. The environmental impact of MBCMs is also evaluated, highlighting their potential for sustainable development in civil engineering applications. The primary issues and challenges for MBCMs in soil curing include the insufficient stability of hydration products and inadequate understanding of curing mechanisms, leading to variable material properties and difficulties in precisely controlling the curing effects in practical engineering. Additionally, the complex composition of MBCMs and the highly variable characteristics of natural soils result in significant differences in curing effectiveness under different conditions, restricting their application scope and posing risks to project costs and quality stability. Full article

The citrus processing industry is an economically important agro-industrial sector worldwide; however, it produces significant amounts of waste annually. The biorefinery concept and the recovery of bio-based materials from agro-industrial residues, including citrus processing waste, are emphasized in the European Green Deal, reflecting the EU’s commitment to fostering circularity. Biotreatment of citrus processing waste, including bioconversion into biomethane, biohydrogen, bioethanol and biodiesel, has been applied to valorize biomass for energy recovery. It can also be composted into a valuable soil conditioners and fertilizers, while raw and fermented citrus residues may exhibit phytoprotective activity. Citrus-derived residues can be converted into materials such as nanoparticles with adsorptive capacity for heavy metals and recalcitrant organic pollutants, and materials with antimicrobial properties against various microbial pathogens, or the potential to remove antibiotic-resistance genes (ARGs) from wastewater. Indeed, citrus residues are an ideal source of industrial biomolecules, like pectin, and the recovery of bioactive compounds with added value in food processing industry. Citrus processing waste can also serve as a source for isolating specialized microbial starter cultures or as a substrate for the growth of bioplastic-producing microorganisms. Solid-state fermentation of citrus residues can enhance the production of hydrolytic enzymes, with applications in food and environmental technology, as well as in animal feed. Certain fermented products also exhibit antioxidant properties. Citrus processing waste may be used as alternative feedstuff that potentially improves the oxidative stability and quality of animal products. Full article

Highly alkaline and highly toxic red mud and other bulk industrial solid wastes become severely accumulated, posing huge risks such as soil degradation and environmental pollution. It is urgent to develop a long-term and stable resource disposal method. In the present research, artificial lightweight aggregates were fabricated utilizing industrial solid residues including red mud, phosphate tailing powder, and fly ash as raw materials. The physical characteristics, microstructure, heavy metal leaching attributes, and freeze–thaw resistance under different mixed water and curing conditions were studied. The results showed that, under the optimal curing condition (steam curing temperature of 80 °C and curing time of 10 h), lightweight aggregates exhibited the best comprehensive performance, with favorable trends in bulk density, apparent density, softening coefficient, and 1 h water absorption. In addition, the impact of extending the curing time on the further enhancement of the cylinder crush strength is limited. The microscopic morphology study showed that the hydration products in lightweight aggregates are primarily N-A-S-H and C-(A)-S-H, forming a strong colloidal structure and evenly dispersed on the particle surface, thereby improving its strength. Moreover, the heavy metal leachates (Cr, Pb, As, Cu, and Ni) from the lightweight aggregates met the environmental discharge criteria for non-hazardous substances. Full article

Staphylococcus shinii (S. shinii) is a coagulase-negative species primarily associated with the degradation of organic matter, contributing to nutrient cycling in natural environments. This species has been mainly studied in clinical and terrestrial contexts, with no previous reports of its presence in marine environments. In this study, we report the first isolation of S. shinii from a marine habitat. The strain SC-M1C was isolated from the Red Sea sponge Negombata magnifica. Whole-genome sequencing confirmed its taxonomic identity as S. shinii. The genome uncovers potential adaptive characteristics that facilitate survival in marine ecosystems, comprising genes associated with osmoregulation, nutrient acquisition, stress response, and resistance to heavy metals. Moreover, multiple genomic islands and plasmids were identified, suggesting a potential role in horizontal gene transfer and environmental adaptability. The presence of biosynthetic gene clusters linked to non-ribosomal peptides, siderophores, and terpene production indicates potential for biochemical versatility beyond traditional metabolic expectations. This study presents the first genomic insights into S. shinii in a marine context, highlighting its ecological significance and adaptive mechanisms in a high-salinity environment. These findings expand our understanding of staphylococcal ecology beyond terrestrial and clinical origins and provide a foundation for exploring the role of S. shinii in marine microbial interactions and environmental resilience. Full article

The natural resistance-associated macrophage proteins (NRAMPs) gene family represents a group of membrane transporter proteins with wide distribution in plants. This family of membrane transporters plays a pivotal role in mediating plant responses to metal stress by coordinating ion transport processes and maintaining cellular metal homeostasis, thereby effectively mitigating the detrimental effects of metal ion stress on plant growth and development. This study conducted a comprehensive genome-wide analysis of the NRAMP gene family in A. tauschii using integrated bioinformatics approaches, as well as the expression pattern when exposed to heavy metal-induced stress. By means of phylogenetic investigation, eleven AetNRAMP proteins were categorized into five distinct subgroups. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis revealed that the majority of NRAMP genes exhibited marked differential expression patterns under specific stress treatments. Subsequently, yeast cells were employed to validate the functions of AetNRAMP1 and AetNRAMP3. It was confirmed that AetNRAMP1 functioned in copper transport, and AetNRAMP3 showed an increase in its expression level under manganese stress. These findings establish a molecular foundation for elucidating the functional specialization of NRAMP gene family members in A. tauschii’s heavy metal detoxification pathways, providing critical genetic evidence for their stress-responsive regulatory networks. Nevertheless, significant knowledge gaps persist regarding its functions in A. tauschii. Research on metal stress resistance in this wheat progenitor species may establish a theoretical foundation for enhancing wheat tolerance and developing improved cultivars. Full article

As emerging pollutants, antibiotic resistance genes (ARGs) have been recognized as originating from diverse sources. Among these, the use of livestock feed and veterinary drugs was identified as the primary source of ARGs in livestock manure. ARGs were found to be widely distributed in global environments, particularly in agriculture-related soils, water bodies, and the atmosphere, posing potential threats to ecological environments and human health. This paper reviewed the degradation mechanisms of ARGs during aerobic composting of livestock manure and the safety evaluation of compost products. Aerobic composting was demonstrated to be an effective method for degrading ARGs, primarily through mechanisms such as high-temperature elimination of ARG-carrying microorganisms, reduction in host bacterial abundance, and inhibition of horizontal gene transfer. Factors including the physicochemical properties of the composting substrate, the use of additives, and the presence of antibiotic and heavy metal residues were shown to influence the degradation efficiency of ARGs, with compost temperature being the core factor. The safety of organic fertilizers encompassed multiple aspects, including heavy metal content, seed germination index, and risk assessments based on ARG residues. The analysis indicated that deficiencies existed in areas such as the persistence of thermotolerant bacteria carrying ARGs, the dissemination of extracellular antibiotic resistance genes (eARGs), and virus-mediated gene transfer. Future research should focus on (1) the removal of thermotolerant bacteria harboring ARGs; (2) the decomposition of eARGs or the blocking of their transmission pathways; (3) the optimization of ultra-high temperature composting parameters; and (4) the analysis of interactions between viruses and resistant hosts. This study reviews the mechanisms, influencing factors, and safety assessment of aerobic composting for degrading ARGs in livestock manure. It not only deepens the understanding of this important environmental biotechnology process but also provides a crucial knowledge base and practical guidance for effectively controlling ARG pollution, ensuring agricultural environmental safety, and protecting public health. Additionally, it clearly outlines the key paths for future technological optimization, thus holding significant implications for the environment, agriculture, and public health. Full article

Heavy metal pollution, particularly copper contamination, threatens the ecological environment and human survival. In response to this pressing environmental issue, the development of innovative remediation strategies has become imperative. Bioremediation technology is characterized by remarkable advantages, including its ecological friendliness, cost-effectiveness, and operational efficiency. In our previous research, Rossellomorea sp. ZC255 demonstrated substantial potential for environmental bioremediation applications. This study investigated the removal characteristics and underlying mechanism of strain ZC255 and revealed that the maximum removal capacity was 253.4 mg/g biomass under the optimal conditions (pH 7.0, 28 °C, and 2% inoculum). The assessment of the biosorption process followed pseudo-second-order kinetics, while the adsorption isotherm may fit well with both the Langmuir and Freundlich models. Cell surface alterations on the Cu(II)-treated biomass were observed through scanning electron microscopy (SEM). Cu(II) binding functional groups were determined via Fourier transform infrared spectroscopy (FTIR) analysis. Simultaneously, the genomic analysis of strain ZC255 identified multiple genes potentially involved in heavy metal resistance, transport, and metabolic processes. These studies highlight the significance of strain ZC255 in the context of environmental heavy metal bioremediation research and provide a basis for using strain ZC255 as a copper removal biosorbent. Full article

One hundred presumptive Pseudomonas isolates, recovered from 15 sites impacted by anthropogenic activity in the Foggia district (Italy), were screened for key adaptive and functional traits important for environmental applications. The isolates were phenotypically characterized for their ability to grow under combined pH (5.0–8.0) and temperature (15–37 °C) conditions, to produce proteolytic enzymes, pigments, and exopolysaccharides, and to tolerate SDS. Moreover, the resistance to six environmentally relevant heavy metals (Cd, Co, Cu, Ni, Zn, As) was qualitatively assessed. The results highlighted wide inter-strain variability, with distinct clusters of isolates showing unique combinations of stress tolerance, enzymatic potential, and resistance profile. PERMANOVA analysis revealed significant effects of both the isolation site and the metal type, as well as their interaction, on the observed resistance patterns. A subset of isolates showed co-tolerance to elevated temperatures and heavy metals. These findings offer an initial yet insightful overview of the adaptive diversity of soil-derived Pseudomonas, laying the groundwork for the rational selection of strains for bioaugmentation in contaminated soils. Full article

Effective management of fecal pollutants in rural sanitation is crucial for environmental health and public safety, especially in developing regions. In this study, temporal and regional variations in nutrient elements, heavy metals, pathogenic microorganisms (PMs), and antibiotic resistance genes (ARGs) of fecal samples from rural toilets in China were investigated. The moisture contents of the fecal samples average 92.7%, decreasing seasonally from 97.4% in summer to 90.6% in winter. The samples’ pH values range from 6.5 to 7.5, with a slight decrease in winter (6.8), while their electrical conductivity varies from 128.1 to 2150 μs/cm, influenced by regional diets. Chromium (9.0–49.7 mg/kg) and copper (31.9–784.4 mg/kg) levels vary regionally, with higher concentrations in Anhui and Guangxi Provinces due to dietary and industrial factors. Zinc contents range from 108.5 to 1648.9 mg/kg, with higher levels in autumn and winter, resulting from agricultural practices and Zn-containing fungicides, posing potential health and phytotoxicity risks. Seasonal and regional variations in PMs and ARGs were observed. Guangxi Province shows the high PM diversity in summer samples, while Jiangsu Province exhibits the high ARGs types in autumn samples. These findings highlight the need for improved waste management and sanitation solutions in rural areas to mitigate environmental risks and protect public health. Continued research in these regions is essential to inform effective sanitation strategies. Full article

Heavy metal pollution represents a pervasive environmental challenge that significantly exacerbates the ever-increasing crisis of antimicrobial resistance and the capacity of microorganisms to endure and proliferate despite antibiotic interventions. This review examines the intricate relationship between heavy metals and AMR, with an emphasis on the underlying molecular mechanisms and ecological ramifications. Common environmental metals, including arsenic, mercury, cadmium, and lead, exert substantial selective pressures on microbial communities. These induce oxidative stress and DNA damage, potentially leading to mutations that enhance antibiotic resistance. Key microbial responses include the overexpression of efflux pumps that expel both metals and antibiotics, production of detoxifying enzymes, and formation of protective biofilms, all of which contribute to the emergence of multidrug-resistant strains. In the soil environment, particularly the rhizosphere, heavy metals disrupt plant–microbe interactions by inhibiting beneficial organisms, such as rhizobacteria, mycorrhizal fungi, and actinomycetes, thereby impairing nutrient cycling and plant health. Nonetheless, certain microbial consortia can tolerate and detoxify heavy metals through sequestration and biotransformation, rendering them valuable for bioremediation. Advances in biotechnology, including gene editing and the development of engineered metal-resistant microbes, offer promising solutions for mitigating the spread of metal-driven AMR and restoring ecological balance. By understanding the interplay between metal pollution and microbial resistance, we can more effectively devise strategies for environmental protection and public health. Full article

This study investigates the use of waste glass powder derived from fluorescent lamps as a partial replacement for cement in mortar production, aiming to valorize this Waste from Electrical and Electronic Equipment (WEEE) and enhance sustainability in the construction sector. Mortars were formulated by substituting 25% of cement by volume with glass powders from fluorescent lamp glass and green bottle glass. The experimental program evaluated mechanical strength, durability parameters and ecotoxicological performance. Results revealed that clean fluorescent lamp mortars showed the most promising mechanical behavior, exceeding the reference in long-term compressive (54.8 MPa) and flexural strength (10.0 MPa). All glass mortars exhibited significantly reduced chloride diffusion coefficients (85–89%) and increased electrical resistivity (almost 4 times higher), indicating improved durability. Leaching tests confirmed that the incorporation of fluorescent lamp waste did not lead to hazardous levels of heavy metals in the cured mortars, suggesting effective encapsulation. By addressing both technical (mechanical and durability) and ecotoxic performance, this research contributes in an original and relevant way to the development of more sustainable building materials. Full article

Background/Objetives: Antimicrobial Resistance (AMR) is a multifaceted issue that the World Health Organization (WHO) identifies as one of the primary threats to global health for humans, animals, and the environment. In Colombia, AMR has been extensively studied at the hospital level; however, there are limited environmental studies, particularly concerning leachates from landfills. The objective of this study was to identify and determine the genetic relationships, as well as the sensitivity profiles to antibiotics and heavy metals, of ten Pseudomonas mendocina isolates from a leachate pond. Methods: Identification was conducted using MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight), while genotyping was performed via rep-PCR. Antibiotic susceptibility to β-lactams, aminoglycosides, and quinolones was assessed using the Kirby-Bauer method. Additionally, sensitivity profile to heavy metals was evaluated using the broth microdilution technique. Results: Rep-PCR analysis indicated that 60% (n = 6/10) of the isolates exhibited a clonal relationship. Sensitivity testing revealed that 30% (n = 3/10) of the isolates displayed reduced sensitivity to aminoglycosides and β-lactams. Finally, the broth microdilution showed that 90% (n = 9/10) of the isolates were tolerant to copper sulfate. Conclusions: These results provide evidence that landfill leachates may serve as a potential reservoir for bacteria harboring antimicrobial resistance determinants. Full article

Leather biodegradation is a complex microbial process with increasing relevance for sustainable waste management. In this study, we investigated bacterial communities responsible for the degradation of leather treated with different tanning agents (chrome, Zeolite, Biole^®) using high-throughput 16S rRNA gene sequencing and metatranscriptomic analysis. Proteobacteria, Bacteroidetes, and Patescibacteria emerged as the dominant phyla, while genera such as Acinetobacter, Pseudomonas, and Sphingopyxis were identified as key contributors to enzymatic activity and potential metal resistance. A total of 1302 enzymes were expressed across all the conditions, including 46 proteases, with endopeptidase La, endopeptidase Clp, and methionyl aminopeptidase being the most abundant. Collagen samples exhibited the highest functional diversity and total enzyme expression, whereas chrome-treated samples showed elevated protease activity, indicating selective pressure from heavy metals. Differential enzyme expression patterns were linked to both the microbial identity and tanning chemistry, revealing genus- and treatment-specific enzymatic signatures. These findings deepen our understanding of how tanning agents modulate the microbial structure and function and identify proteases with potential applications in the bioremediation and eco-innovation of leather waste processing. Full article