Nanobioremediation of heavy metals: Perspectives and challenges

Nanomaterials and biochar mediated remediation of emerging contaminants

The unrestricted release of various toxic substances into the environment is a critical global issue, gaining increased attention in modern society. Many of these substances are pristine to various environmental compartments known as contaminants/emerging contaminants (ECs). Nanoparticles and emerging sorbents enhanced remediation is a compelling methodology exhibiting great potential in addressing EC-related issues and facilitating their elimination from the environment, particularly those compounds that demonstrate eco-toxicity and pose considerable challenges in terms of removal. It provides a novel technique enabling the secure and sustainable removal of various ECs, including persistent organic compounds, microplastics, phthalate, etc. This extensive review presents a critical perspective on the current advancements and potential outcomes of nano-enhanced remediation techniques such as photocatalysis, nano-sensing, nano-enhanced sorbents, bio/phyto-remediation, which are applied to clean-up the natural environment. In addition, when dealing with residual contaminants, special attention is paid to both health and environmental implications; therefore, an evaluation of the long-term sustainability of nano-enhanced remediation methods has been considered. The integrated mechanical approaches were thoroughly discussed and presented in graphical forms. Thus, the critical evaluation of the integrated use of most emerging remediation technologies will open a new dimension in environmental safety and clean-up program.

Evaluation of the Differential Postbiotic Potential of Shewanella putrefaciens Pdp11 Cultured in Several Growing Conditions

The increased knowledge of functional foods has led to the development of a new generation of health products, including those containing probiotics and products derived from them. Shewanella putrefaciens Pdp11 (SpPdp11) is a strain described as a probiotic that exerts important beneficial effects on several farmed fish. However, the use of live probiotic cells in aquaculture has limitations such as uncertain survival and shelf life, which can limit their efficacy. In addition, its efficacy can vary across species and hosts. When probiotics are administered orally, their activity can be affected by the environment present in the host and by interactions with the intestinal microbiota. Furthermore, live cells can also produce undesired substances that may negatively impact the host as well as the risk of potential virulence reversion acquired such as antibiotic resistance. Therefore, new alternatives emerged such as postbiotics. Currently, there is no knowledge about the postbiotic potential of SpPdp11 in the aquaculture industry. Postbiotic refers to the use of bacterial metabolites, including extracellular products (ECPs), to improve host physiology. However, the production of postbiotic metabolites can be affected by various factors such as cultivation conditions, which can affect bacterial metabolism. Thus, the objective of this study was to evaluate the postbiotic potential of ECPs from SpPdp11 under different cultivation conditions, including culture media, temperature, growth phase, and salinity. We analyzed their hydrolytic, antibacterial, antiviral, and cytotoxic capacity on several fish cell lines. The results obtained have demonstrated how each ECP condition can exert a different hydrolytic profile, reduce the biofilm formation by bacterial pathogens relevant to fish, lower the titer of nervous necrosis virus (NNV), and exert a cytotoxic effect on different fish cell lines. In conclusion, the ECPs obtained from SpPdp11 have different capacities depending on the cultivation conditions used. These conditions must be considered in order to recover the maximum number of beneficial capacities or to choose the appropriate conditions for specific activities.

Mechanistic and recent updates in nano-bioremediation for developing green technology to alleviate agricultural contaminants

The rise in environmental pollutant levels in recent years is mostly attributable to anthropogenic activities such as industrial, agricultural and other activities. Additionally, these activities may produce excessive levels of dangerous toxicants such as heavy metals, organic pollutants including pesticide and herbicide chemicals, and sewage discharges from residential and commercial sources. With a focus on environmentally friendly, sustainable technology, new technologies such as combined process of nanotechnology and bioremediation are urgently needed to accelerate the cost-effective remediation process to alleviate toxic contaminants than the conventional remediation methods. Numerous studies have shown that nanoparticles possess special qualities including improved catalysis and adsorption as well as increased reactivity. Currently, microorganisms and their extracts are being used as promising, environmentally friendly catalysts for engineered nanomaterial. In the long term, this combination of both technologies called nano-bioremediation may significantly alter the field of environmental remediation since it is more intelligent, safe, environmentally friendly, economical and green. This review provides an overview of soil and water remediation techniques as well as the use of nano-bioremediation, which is made from various living organisms. Additionally, current developments related to the mechanism, model and kinetic studies for remediation of agricultural contaminants have been discussed.

Nanotechnology in the Restoration of Polluted Soil

The advancements in nanoparticles (NPs) may be lighting the sustainable and eco-friendly path to accelerate the removal of toxic compounds from contaminated soils. Many efforts have been made to increase the efficiency of phytoremediation, such as the inclusion of chemical additives, the application of rhizobacteria, genetic engineering, etc. In this context, the integration of nanotechnology with bioremediation has introduced new dimensions for revamping the remediation methods. Hence, advanced remediation approaches combine nanotechnological and biological remediation methods in which the nanoscale process regulation supports the adsorption and deterioration of pollutants. Nanoparticles absorb/adsorb a large variety of contaminants and also catalyze reactions by lowering the energy required to break them down, owing to their unique surface properties. As a result, this remediation process reduces the accumulation of pollutants while limiting their spread from one medium to another. Therefore, this review article deals with all possibilities for the application of NPs for the remediation of contaminated soils and associated environmental concerns.