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Heavy metal and pesticide pollution have become an inevitable part of the modern industrialized environment that find their way into all ecosystems. Because of their persistent nature, recalcitrance, high toxicity and biological enrichment, metal and pesticide pollution has threatened the stability of the environment as well as the health of living beings. Due to the environmental persistence of heavy metals and pesticides, they get accumulated in the environs and consequently lead to food chain contamination. Therefore, remediation of heavy metals and pesticide contaminations needs to be addressed as a high priority. Various physico-chemical approaches have been employed for this purpose, but they have significant drawbacks such as high expenses, high labor, alteration in soil properties, disruption of native soil microflora and generation of toxic by-products. Researchers worldwide are focusing on bioremediation strategies to overcome this multifaceted problem, i.e., the removal, immobilization and detoxification of pesticides and heavy metals, in the most efficient and cost-effective ways. For a period of millions of evolutionary years, microorganisms have become resistant to intoxicants and have developed the capability to remediate heavy metal ions and pesticides, and as a result, they have helped in the restoration of the natural state of degraded environs with long term environmental benefits. Keeping in view the environmental and health concerns imposed by heavy metals and pesticides in our society, we aimed to present a generalized picture of the bioremediation capacity of microorganisms. We explore the use of bacteria, fungi, algae and genetically engineered microbes for the remediation of both metals and pesticides. This review summarizes the major detoxification pathways and bioremediation technologies; in addition to that, a brief account is given of molecular approaches such as systemic biology, gene editing and omics that have enhanced the bioremediation process and widened its microbiological techniques toward the remediation of heavy metals and pesticides.

Vermicompost is an organic fertilizer rich in nutrients, beneficial microbes, and plant growth hormones that not only enhances the growth of crops but also contributes to the improvement in the physicochemical and biological properties of the soil. However, its lower nutrient content makes it less preferable among farmers and limits its applicability. Here, we investigate, for the first time, nutrient enrichment of vermicompost by supplementing the free-floating macrophyte biomass with cow manure and organic nutrient supplements (eggshell, bone meal, banana peel, and tea waste). Free-floating macrophytes are aquatic plants that are found suspended on the water surface, playing a significant role in the structural and functional aspects of aquatic ecosystems. However, uncontrolled proliferation of these macrophytes endangers these ecosystems, having both economic and ecological implications; therefore, they need to be managed. Results showed an enhanced total nitrogen (2.87%), total phosphorus (0.86%), total potassium (3.74%), and other nutrients in vermicompost amended with cow manure and nutrient supplements. Highest biomass gain (710–782 mg), growth rate (11.83–13.04 mg), and reproduction rate (3.34–3.75 cocoons per worm) was also observed, indicating that amending bulking agent and nutrient supplements not only enhance the nutrient content of the final product but also improve overall earthworm activity. The stability and maturity of vermicompost, as indicated by C/N (<20) and Germination Index (>80), indicates that vermicompost obtained is suitable for agricultural applications. The study concluded that amendment of cow manure and organic nutrient supplements results in producing mature and nutrient-enriched vermicompost suitable for sustainable agricultural production.

More than 70% of our planet is covered by extremely cold environments, nourishing a broad diversity of microbial life. Temperature is the most significant parameter that plays a key role in the distribution of microorganisms on our planet. Psychrophilic microorganisms are the most prominent inhabitants of the cold ecosystems, and they possess potential cold-active enzymes with diverse uses in the research and commercial sectors. Psychrophiles are modified to nurture, replicate, and retain their active metabolic activities in low temperatures. Their enzymes possess characteristics of maximal activity at low to adequate temperatures; this feature makes them more appealing and attractive in biotechnology. The high enzymatic activity of psychrozymes at low temperatures implies an important feature for energy saving. These enzymes have proven more advantageous than their mesophilic and thermophilic counterparts. Therefore, it is very important to explore the efficiency and utility of different psychrozymes in food processing, pharmaceuticals, brewing, bioremediation, and molecular biology. In this review, we focused on the properties of cold-active enzymes and their diverse uses in different industries and research areas. This review will provide insight into the areas and characteristics to be improved in cold-active enzymes so that potential and desired enzymes can be made available for commercial purposes.

Himalayan ecosystem is characterized by its fragile climate with rich repositories of biodiversity. Waste collection and disposal are becoming increasingly difficult due to topographical variations. Aporrectodea caligenosa , a versatile psychrophillic soil dweller, is a useful biocatalyst with potent bio-augmented capability for waste treatment at low temperatures. Microcosm experiments were conducted to elucidate the comprehensive nature of biogenic nitrogen transformation to NH 4 + and NO 3 − produced by coupling of earthworm-microbes. Higher biogenic recovery of NH 4 + -N from coprolites of garden soil (47.73 ± 1.16%) and Himalayan goat manure (86.32 ± 0.92%) with an increment of 14.12 and 47.21% respectively over their respective control (without earthworms) with a linear decline beyond 4th week of incubation was reported. NO 3 – -N recovery progressively sustained in garden soil and goat manure coprolites during entire incubation with highest 81.81 ± 0.45 and 87.20 ± 1.08 µg-N g −1 dry weight recorded in 6th and 5th week of incubation respectively and peak increments as 38.58 and 53.71% relative to respective control (without earthworms). Declined NH 4 + –N in coprolites at low temperature (15.0 ± 2.0 °C) evidenced increased nitrification rates by taking over the process by abundant nitrifying microbes. Steady de-nitrification with progressive incubation on an average was 16.95 ± 0.46 ng-N g −1 per week and 21.08 ± 0.87 ng-N g −1 per week compared to 14.03 ± 0.58 ng-N g −1 per week and 4.50 ± 0.31 ng-N g −1 per week in respective control treatments. Simultaneous heterotrophic nitrification and aerobic denitrification (SHNAD) was found to be a prominent bioprocess at low temperature that resulted in high and stable total nitrogen and nitrate accumulation from garden soil and goat manure with relative recovery efficiency of 11.12%, 14.97% and 14.20%; 19.34%. A. caligenosa shows promising prospects for mass applicability in biogenic N removal from manure of Himalayan goat.

Despite its limited exploration, Nymphaea mexicana Zucc. can be beneficial if pharmacology, isolation, and biological evaluation are given attention. It is an aquatic species that belongs to the family Nymphaeaceae. The thrust area of the work was the extraction, isolation, and biological evaluation of different extracts of the N. mexicana Zucc. plant. The primary goal of this research was to assess the antimicrobial, antioxidant, and anticancer activities of the extracts and to isolate the target naringenin compound. Comparative FT IR analysis of different extracts of this plant revealed the presence of functional groups of plant secondary metabolites, including polyphenols, flavonoids, terpenoids, esters, amines, glycosides, alkanes, alkaloids, fatty acids, and alcohols. Moderate free radical scavenging potential has been achieved for the various extracts via reducing power and DPPH assays. While cytotoxic activity was evaluated by colorimetric and lactate dehydrogenase cell viability tests on potent cancer cell lines. Lung adenocarcinoma epithelial cells (A-549), and breast cells (MC-7) were treated with MeOH extract. The antimicrobial activity against bacterial strains was evaluated using Gram-positive and -negative cultures, where maximum and minimum inhibition zones were recorded for different strains, including 1.6–25.6 μg/mL for Streptococcus aureus, using the agar well diffusion method. In addition, the anti-inflammatory activity of different extracts of N. mexicana Zucc. was evaluated in a nitrite radical scavenging assay with high concentrations of secondary metabolites, which are important against human pathogens and other diseases.

The intensive use of inorganic fertilizers and pesticides in the agricultural field has globally destroyed soil fertility, killed beneficial microorganisms, and also decreased natural resistance in crops, thereby making them more vulnerable to diseases besides affecting human health and the environment. To overcome these problems, it is very important to shift our attention towards eco-friendly alternatives like vermicompost and vermicompost tea which not only can increase crop growth and yield, suppress diseases and pests sustainably but can also protect human health and the environment. Vermicompost with its rich nutrient content, plant growth promoters like auxins, gibberellins, cytokinins, and beneficial microbes not only improves the growth and yield of crops but also increases the diversity and activity of antagonistic microbes and nematodes, which helps to suppress pests and diseases caused by soil-borne phytopathogens. Vermicompost tea also has a tremendous potential to protect plants from diseases and its application to plants can coat leaf surfaces and reduce available sites for pathogen infection or increases microbial diversity that can kill harmful pathogens. Here, we review recent scientific achievements towards the management of crop diseases and pests by these organic amendments and the major points are the following: (1) production of vermicompost and vermicompost tea, (2) management of crop pests and diseases by vermicompost and vermicompost tea, and (3) the possible mechanisms and some important factors involved in the suppression of diseases and pests. Finally, we conclude that by using these eco-friendly organic amendments as a replacement to inorganic pesticides and fungicides, diseases and pests can be managed successfully without affecting human health and the environment and chemical-free food can be provided to humankind in the future.

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate.

The environmental impacts of plastic have attracted the interest of the scientists, media, and policymakers, but the impact of microplastics (MPs) on our environment remains largely unknown. These novel pollutants are so widespread that the scientific community has defined the present historical epoch as “The Plasticene”. There is growing concern over the bioaccumulation and entry of these miniature plastic particles released from almost every article of daily use into the food chains, which will ultimately contaminate the human population. Given the presence of these pollutants in almost every strata and biome of the earth, adsorption of other toxic pollutants and generation of novel categories of chemicals, MP pose an eminent challenge to almost every biotic community. At present times, we have very little knowledge about the possible effects of micropollutants as risk assessment and risk management rely on standardized data and reliable methodology adopted, so in present times it is impossible to evaluate the toxic response and deleterious effects on biotic communities. The detailed understanding of origin, exposure pathways, toxic response of biota, remediation options, and precautionary operations are of prime importance for averting the plastic disaster. MPs significant affect rooting ability of plants, reduce photosynthetic ability by dysregulation of chlorophyll a/chlorophyll b ratios and cause imbalance in carbon/nitrogen balance. MPs have most prominent effect on aquatic animals where they cause feeding disruption, alterations in metabolism, hormonal imbalance and henceforth reproductive problems. On cellular levels MPs causes cytotoxicity, nephrotoxicity, immune dysregulation, neurotoxicity and genotoxicity. MPs have been found to affect the microbes which results in replacement of beneficial organisms by harmful organisms at niche areas and MPs acts as vehicle and transport agents for transport and proliferation of harmful organism like Ostreopsis and Coolia and Vibrio genera. Owing to the deleterious effects on environment and biota, various remedial measures proposed by researchers includes biodegradation, coagulation, photo-catalytic degradation and thermal degradation. Therefore, current manuscript attempts to review the status of these pollutants in various biomes of the biosphere, their possible toxic effects on residents of the hydrosphere, atmosphere, and lithosphere, their effect on human health, and various remediation processes with the intention of special and surgical emphasis on future research in the area for fulfillment of the knowledge gap.

Two million tonnes of pesticides are currently used globally to improve crop production, yet these pesticides induce adverse effects on soil quality and biodiversity. Moreover, less than 1% of pesticides reach the target pests, while the rest contaminate the surrounding environment. In particular, earthworms are exposed to pesticides and are thus an ideal biological model for ecotoxicological research. Here, we review acute and sub-lethal effects of pesticides on earthworms. We found that pesticides alter growth, reproduction, behaviour, essential enzymes, and DNA of earthworms, even at low pesticide concentrations. These sub-lethal biomarkers allow to evaluate the overall response of an earthworm to pesticides, and to identify the risk for other non-target organisms.

Phosphorus (P) is one of the essential macronutrients for plant metabolism. Regardless of its great quantity in inorganic and organic forms, it is generally inaccessible for plant utility due to bond formation with other ions present in soil. Due to the excessive use of agrochemicals, environmental issues have reached their peak. This has increased the interest of the scientific community in finding a sustainable alternative to chemical fertilisers. Diverse microbes like Rhizobium spp., Serratia spp., Pseudomonas spp., Bacillus spp., Azotobacter spp., Penicillium spp., Rhizopus spp., Fusarium spp., and various actinomycetes have been isolated and screened as phosphorus solubilizing microorganisms (PSMs). The PSMs also act as biological control agents (bioagents) and help to withstand extreme stress circumstances (like heavy metal toxicity) by producing ACC deaminase. With the advent of time, organic farming is gaining attention as this technology is highly eco-friendly, so utilisation of potential microorganisms for solubilisation of phosphorus will improve soil health and crop productivity. PSMs possess significant heavy metal remediation potential; therefore, they can be used in restoration of contaminated soil as well as in enhancing plant health. This review will provide in-depth knowledge about PSMs and their role in sustainable agriculture and bioremediation of toxicants.