Bioremediation Of Pesticides Research Articles

Agricultural Pest Management: The Role of Microorganisms in Biopesticides and Soil Bioremediation.

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.

Unveiling the positive impacts of the genus Rhodococcus on plant and environmental health

Organic farming has emerged as a sustainable solution to the adverse effects (diminished nutritional value, compromised food quality, environmental contamination, and public health hazards) that are usually associated with harmful chemical pesticides. To overcome such loss, one must explore the plant-associated microbes that are the naturally occurring root commensal and could positively improve crop health. In this review, we highlight the importance of the bacterial genus Rhodococcus, a subset of Actinobacteria that carries immense potential in enhancing crop yield and is associated with bioremediation of toxic pesticides and other chemicals to improve soil health. However, it has been noticed that few species of Rhodococcus are pathogenic for the plant (R. fascians) as well as humans/animals (R. equi). But still, the majority of Rhodococcus isolates are found to be non-pathogenic and carry substantial beneficial traits. Here, we have attempted to comprise those beneficial traits of the different members of the genus Rhodococcus. The main emphasis of this review article is to explore the major areas such as enzyme production, phytohormone synthesis, growth regulation, siderophore production, bioremediation, organic compound degradation, and environmental pollution control. Opinions towards the applications of advanced methodologies for utilizing the cumulative prospective potential of the genus Rhodococcus have also been discussed in the different sections of the review. Conclusively, this article gathers the scattered information from the past and recent literature about this bacteria and provides the future direction about how it can improve plant/soil health and eliminate toxic chemicals and environmental pollutants.

Transcriptomic analysis of molecular mechanisms underlying the biodegradation of organophosphorus pesticide chlorpyrifos by Lactobacillus delbrueckii ssp. bulgaricus in skimmed milk

Bioremediation of organophosphorus pesticides in contaminated foodstuffs using probiotics has been increasingly under the spotlight in recent years, though the biodegradation mechanism and derived intermediate products remain unclear. This study aimed to help fill this knowledge gap and examined the degradation mechanism of organophosphorus pesticide, chlorpyrifos, in milk by Lactobacillus delbrueckii ssp. bulgaricus using gas chromatography- tandem mass spectrometry (GC-MS/MS) combined with transcriptome analysis. After the strain was cultured for 20 h in the presence of chlorpyrifos, differential expressions of 383 genes were detected, including genes probably implicated during chlorpyrifos degradation such as those related to hydrolase, phosphoesterase, diphosphatase, oxidoreductase, dehydratase, as well as membrane transporters. GC-MS/MS analysis revealed the changes of secondary metabolites in L. bulgaricus during milk fermentation due to chlorpyrifos stress. 6-Methylhexahydro-2H-azepin-2-one, 2,6-dihydroxypyridine and methyl 2-aminooxy-4-methylpentanoate as intermediates, along with the proposed pathways, might be involved in chlorpyrifos biodegradation by L. bulgaricus.

Laccase-assisted Bioremediation of Pesticides: Scope and Challenges

Abstract: Laccase (Benzenediol: oxygen oxidoreductase; E.C.1.10.3.2), a multicopper oxidase that is a known lignin-degrading enzyme, can catalyse an ample array of substrates, from phenolic, nonphenolic compounds, aromatic amines, diamines, heterocyclic compounds to organic/inorganic metal compounds, etc., bestowed they have not too high redox potentials. Despite many laccase-producing organisms like bacteria, insects, plants, and animals, white rot filamentous fungi are the best producers of this enzyme. In the presence of laccase, pesticides (fungicides, herbicides, insecticides, etc.) of various chemical compositions (organophosphates, organochlorines, carbamates, pyrethrin & pyrethroids, etc.) are oxidized into the water with collateral reduction of four electrons of molecular oxygen with various efficiencies. Bioremediation efficiency can be increased in the presence of various natural or synthetic mediators, viz. ABTS, violuric acid, 1- hydroxy benzotriazole, vanillin, syringaldehyde, PEG, etc. Immobilized laccase on various supporting materials increased the enzyme's stability, reliability, and reusability for continuous application, particularly for industrial processes. The present review discusses the structure, catalytic cycle, general mechanism of oxidation, and various scopes and challenges of pesticide degradation by this multifaceted biocatalyst which could lead to a green sustainable environment.

Fabrication and characterization of polyvinyl alcohol-chitosan composite nanofibers for carboxylesterase immobilization to enhance the stability of the enzyme

Electrospinning stands out as a flexible and viable method, presenting designed nanoscale materials with customized properties. This research demonstrates the immobilization of carboxylesterase protein Ha006a, reported for its adequacy in pesticide bioremediation by utilizing the electrospinning strategy. This strategy was utilized to create nanofibers by incorporating variable mixtures of biodegradable and cost-effective polyvinyl alcohol (PVA)-chitosan (CS) nanofiber solution (PVA100, PVA96, PVA94, PVA92 and PVA90). All the mixtures were electrospun at a reliable voltage of 21 kV, maintaining a gap of 12 cm from the nozzle. The Ha006a, sourced from Helicoverpa armigera, was consolidated into the optimized PVA90 polymer mixture. The electrospun nanofibers experienced comprehensive characterization utilizing distinctive microscopy and spectroscopy procedures counting FESEM, TGA, XRD and FTIR. The comparative investigation of the esterase property, ideal parameters and stability of the unbound and bound/immobilized Ha006a was scrutinized. The results uncovered an essential elevation in the ideal conditions of enzyme activity post-immobilization. The PVA-CS control nanofiber and Ha006a-PVA-CS showed a smooth structure, including an average breadth of around 170.5 ± 44.2 and 222.5 ± 66.5 nm, respectively. The enzyme-immobilized nanofibers displayed upgraded stability and comprehensive characterization of the nanofiber, which guaranteed genuineness and reproducibility, contributing to its potential as a potent device for bioremediation applications. This investigation opens the way for the manufacture of pesticide-resistant insect enzyme-based nanofibers, unlocking their potential for assorted applications, counting pesticide remediation and ensuring environmental sustainability.

Coupling Peptide-Based Encapsulation of Enzymes with Bacteria for Paraoxon Bioremediation.

The catalytic efficiency of enzymes can be harnessed as an environmentally friendly solution for decontaminating various xenobiotics and toxins. However, for some xenobiotics, several enzymatic steps are needed to obtain nontoxic products. Another challenge is the low durability and stability of many native enzymes in their purified form. Herein, we coupled peptide-based encapsulation of bacterial phosphotriesterase with soil-originated bacteria, Arthrobacter sp. 4Hβ as an efficient system capable of biodegradation of paraoxon, a neurotoxin pesticide. Specifically, recombinantly expressed and purified methyl parathion hydrolase (MPH), with high hydrolytic activity toward paraoxon, was encapsulated within peptide nanofibrils, resulting in increased shelf life and retaining ∼50% activity after 132 days since purification. Next, the addition of Arthrobacter sp. 4Hβ, capable of degrading para-nitrophenol (PNP), the hydrolysis product of paraoxon, which is still toxic, resulted in nondetectable levels of PNP. These results present an efficient one-pot system that can be further developed as an environmentally friendly solution, coupling purified enzymes and native bacteria, for pesticide bioremediation. We further suggest that this system can be tailored for different xenobiotics by encapsulating the rate-limiting key enzymes followed by their combination with environmental bacteria that can use the enzymatic step products for full degradation without the need to engineer synthetic bacteria.

In situ microbial bioremediation of obsolete pesticides at their disposal sites

Soil pollution by pesticides is a global problem in many countries, including Kyrgyzstan. Currently, 50 storage facilities for obsolete banned pesticides exist, severely threatening the surrounding populations and environment. In this study, in situ bioremediation technology was used to remove pesticide contamination from soil around the storage facilities. Three conditions were tested: application of fertile soil and bioproduct, application of fertile soil and no bioproduct (Control 1), and application of fertile soil and no bioproduct (Control 2). An aerobic bioremediation approach was used: the treatment was applied directly to the contaminated soil. For the bioaugmentation, three selected active degrading bacterial species were used: Stenotrophomonas sp. (Ps-B strain), L. fusiformis (SA-4 strain) and E. cloacae (SB-2 strain). Regular aeration, loosening and watering were performed during the subsequent months to create the conditions required to activate the local microflora and the degrading activity of the bacterial species in the bioproduct. The bioproduct of three active bacteria species has demonstrated a high pesticide decomposition effect. The pesticides were degraded from 85.6 to 99.0 ± 0.05% within six months of initiating the bioremediation process. The efficiency of the degradation process depended on optimum atmospheric conditions, that is, temperature, pH, and moisture content of the soil. Our study recommends using the agrotechnical and biotechnological approach for moderately pesticide-polluted soils and pesticide storage areas.

Development of halotolerant multi-pesticides degraders for wastewater treatment

The biotreatment performance of high saline wastewater containing multiple pesticides is significantly reduced because the growth and metabolism of activated sludge microbial communities are severely impaired by high osmotic pressure and joint toxicity of multiple pesticides. In this study, Halomonas cupida J9 was metabolically engineered by chromosomal integration of three different pesticide hydrolase genes, to create a halotolerant multi-pesticides degrader. In batch degradation experiments, the finally constructed strain J9U-PVG was able to simultaneously degrade chlorpyrifos (organophosphate), carbaryl (carbamate) and α-cypermethrin (pyrethroid) in mineral salt medium supplemented with 4 g/L glucose and 60 g/L NaCl. Total cell lysate of J9U-PVG showed obvious degradation activity against chlorpyrifos, carbaryl and α-cypermethrin. Moreover, introduced Vitreoscilla hemoglobin (VHb) can enhance oxygen-sequestering capability of J9U-PVG and introduced green fluorescent protein (GFP) can be used as a biomarker to track the activity and movement of J9U-PVG in natural environments. More importantly, J9U-PVG could simultaneously and completely degrade chlorpyrifos, carbaryl and α-cypermethrin in high saline river water. Here, we demonstrate for the first time the successful construction of a halotolerant multi-pesticides degrader. This study underscores the value of H. cupida J9 as a promising chassis for the development of a halotolerant pesticide bioremediation platform. In the future, synthetic biology may serve as a powerful tool for expanding the catalytic repertoire of extremophiles for bioremediation of extreme environments.

Effects of the Pesticide Carbofuran on Two Species of Chlorophyceae (Desmodesmus communis and Pseudopediastrum boryanum) and Their Pesticide Bioremediation Ability.

Carbofuran is one of the most toxic broad-spectrum pesticides. We evaluated the effects of carbofuran on two species of microalgae, Pseudopediastrum boryanum and Desmodesmus communis, through measurements of cell viability, biomass, chlorophyll content, and the production of reactive oxygen species (ROS). The ability of these algae to remove carbofuran dissolved in the media was also determined. For the evaluations, both microalgae species were exposed to carbofuran (FURADAN 350 SC®) at concentrations of 100, 1000, and 10,000 µg L-1 for 7 days. Algae cell viability and chlorophyll-a concentration were not affected by the presence of carbofuran. Both species grew when exposed to the pesticide; however, the microalgae D. communis grew less than its respective control when exposed to the highest concentration (10,000 µg L-1 of carbofuran), indicating an adverse effect of the pesticide on this species. A significant increase in ROS production was observed in D. communis and P. boryanum when exposed to the highest concentration tested. The microalgae P. boryanum completely removed carbofuran in the media within 2 days, regardless of the concentration, whereas D. communis achieved the same result only after 5 days of exposure. Growth inhibition was observed only until the disappearance of carbofuran from the media. The present study suggests the use of microalgae, mainly P. boryanum, as potential tools for the remediation of environments contaminated by carbofuran because of their resistance to the insecticide and their ability to remove it rapidly from water. Environ Toxicol Chem 2024;43:926-937. © 2023 SETAC.

Invasive plant-derived biochar for sustainable bioremediation of pesticide contaminated soil

Managing invasive plant presents a significant challenge to both the environment and the economy. There is an opportunity to address this issue by utilizing invasive plants as a sustainable and cost-effective source of valuable functional materials for environmental remediation. In this study, a promising Mikania micrantha biochar (MB) was synthesized by pyrolyzing an invasive plant, which was utilized for bacterial immobilization and adsorption of contaminants. By embedding Proteus terrae ZQ02-MB within a polyvinyl alcohol-sodium alginate gel to create a biochar-modified bacterial microsphere (BBM), the superior degradation of pesticide contaminants was observed. Taking chlorothalonil (CHT) as an example, field experiments demonstrated that BBM achieved a removal efficiency of 59.8% by the third day. Additionally, BBM not only improved the richness and diversity of soil bacteria but also enhanced the microbial community structure by the seventh day. On this basis, the adsorption capacity of MB, biofilm growth promoting ability of BBM, and the CHT mineralization ability of strain ZQ02 were validated as a joint mechanism to promote efficient CHT removal. Overall, this study proposes a composite model of invasive plant-derived biochar loaded microorganisms, which has great potential in eliminating pollutant residues and paves new paths to develop strategies for reusing invasive species resources.

Pantoea: A Versatile bacterial Candidate of Agricultural Importance

Genus Pantoea is a diverse group of the family Enterobacteriaceae which inhabit various ecological niches. Various species of Pantoea are found associated with a diverse host range that include plants, animals, insects and humans. Besides this Pantoea spp. has been widely distributed in nature including water, soil, dairy products, meat and fish. It is commonly associated with plants as epiphyte or pathogen. Pantoea was first recognized as a genus about 25 years ago, but since then, approximately 20 species with a wide range of characteristics have been discovered. Identification of plant-pathogenic Pantoea species is difficult, due to the high degree of phenotypic similarity between species of this genus and related Enterobacteriaceae. Pantoea species are typically characterized based on colony morphology, physiological and biochemical tests, and in some cases, fatty acid analysis or quinone composition. These have a wide range of plant hosts where they live as nonpathogenic endophytes as well as epiphytes that colonize the leaves, stems and roots. In this perspective, some Pantoea strains can be beneficial to the plant host by providing growth promoting substances such as the plant-growth hormone indole-acetic acid (IAA), phosphate solubilization or nitrogen fixation. Number of Pantoea species are also involved in bioremediation of various pesticides and organic chemical compounds. This indicates the potential to degrade some recalcitrant and xenobiotic compounds. Some Pantoea strains also provide effective protection to plants against various bacterial and fungal diseases and post-harvest fruit rots. On the other hand, some of the species are recognized as a human pathogen and has led to controversy as limited documented cases of P. agglomerans bacteremia and infections have been reported. Most of the cases reported among immunocompromised patients or the pediatric population. Thus, Pantoea is a multifaceted bacterium that plays a significant role in agriculture as a plant growth promoter by producing hormone like IAA, inorganic pollutant degradation by producing potent enzymes and also protects some plants against pathogens by producing antibacterial and antifungal compounds. In some cases, these also cause diseases in human beings. Therefore, this genus is very important for studies. In this review, the industrial, agricultural as well as ecological significance of the genus Pantoea is emphasized.

Enhanced bioremediation of pesticides contaminated soil using organic (compost) and inorganic (NPK) fertilizers

This research examined the bioremediation of pesticides (Carbofuran and Paraquat) contaminated farmyard soil using compost and Nitrogen, Phosphorus, and Potassium (NPK) fertilizer. Microcosms representing each treatment were set-up in triplicates. Biostimulation was done using two concentrations (0.5 % and 1.0 % w/w) of NPK fertilizer and compost, following pesticides application at recommended rates [Carbofuran (1 g/kg) and Paraquat (5 ml/kg)] and four times the recommended rates. Two control soils were set-up; Abiotic control (sterile farmyard soil + pesticide) and Control (farmyard soil without treatment). Monitoring of the dynamics in microbial community abundance, and pesticide residues during the biostimulation period was done weekly for 28 days, using standard enumeration method, and High Performance Liquid Chromatography (HPLC), respectively. At the end of the monitoring period, considerable reduction in pesticide residues across the treatment set-ups was recorded. In Carbofuran-treated soils, there were no complete, but considerable losses in residual pesticide, however, in most of the Paraquat-treated soils, there were complete losses within 21 days. Lower pesticide residues were recorded in set-ups amended with compost than NPK, across both Carbofuran and Paraquat-treated soils. After pesticides application, decreases in microbial counts were recorded at Day 7 across all the treatments, followed by increases from Day 14–21, then decreases at Day 28. Microbial counts were lower in Carbofuran than in Paraquat-treated soils irrespective of nutrient (compost and NPK) amendments. Bacterial and fungal counts were in the magnitude of 106 and 105 CFU/g soil, respectively. Also, increased counts were recorded for Actinomycetes, Nitrifiers, Phosphate solubilizers across all treatments, and were in magnitude of 103–104 CFU/g soil. Soil microorganisms could breakdown and eliminate large concentrations of Carbofuran and Paraquat in compost-amended soils than in NPK-amended soils. This study suggests that bioremediation of pesticides contaminated soils can be achieved and enhanced by stimulating the indigenous microbial community with requisite nutrients (compost).

Exploring microbial diversity responses in agricultural fields: a comparative analysis under pesticide stress and non-stress conditions

Exposure to pesticides changes the microbial community structure in contaminated agricultural fields. To analyze the changes in the native microbial composition qRT-PCR, a metagenomic study was conducted. The qRT-PCR results exhibited that the uncontaminated soil has a higher copy number of 16S rDNA relative to the soil contaminated with pesticide. Metagenome analysis interprets that uncontaminated soil is enriched with proteobacteria in comparison with pesticide-contaminated soil. However, the presence of Actinobacteria, Firmicutes, and Bacteroides was found to be dominant in the pesticide-spiked soil. Additionally, the presence of new phyla such as Chloroflexi, Planctomycetes, and Verrucomicrobia was noted in the pesticide-spiked soil, while Acidobacteria and Crenarchaeota were observed to be extinct. These findings highlight that exposure to pesticides on soil significantly impacts the biological composition of the soil. The abundance of microbial composition under pesticide stress could be of better use for the treatment of biodegradation and bioremediation of pesticides in contaminated environments.

Bioremediation of Neonicotinoid Pesticide, Imidacloprid, Mediated by Bacillus cereus.

Imidacloprid, a toxic pesticide of the chloronicotinyl category, is employed extensively in agricultural fields, and its exposure causes serious health issues. Biodegradation is considered to be a green and economical approach to remediate pesticides. Herein, imidacloprid degradation efficiency of Bacillus sp. is highlighted, among which Bacillus cereus exhibited the greatest degradation; optimization of experimental variables (pH, imidacloprid and agitation time) via Box-Behnken factorial design and analysis of variance (ANOVA) revealed 92% biodegradation at the initial substrate concentration of 0.03 mM, aerobically in 11 days under favorable pH 7. The subsequent metabolites, identified through liquid chromatography-mass spectrometry, were 5-hydroxy imidacloprid, imidacloprid-guanidine and 6-chloronicotinic acid.

Esterase and ALDH dehydrogenase-based pesticide degradation by Bacillus brevis 1B from a contaminated environment

The isolated bacterial strain (Bacillus brevis strain 1 B) showed a maximum tolerated level of 450 mg L−1 of the selected pesticides namely: imidacloprid, fipronil, cypermethrin, and sulfosulfuron. Within 15 days of the experiment, strain 1 B was able to reduce up to 95% of a pesticide mixture (20 mg L−1) in a carbon-deficient medium (minimal medium). The optimal conditions obtained using Response Surface Methodology (RSM) were: inoculums; 2.0 × 107 CFU mL−1, shaking speed; 120 rpm, and pesticide concentration; 80 mg L−1. After 15 days of soil-based bioremediation using strain 1 B, the degradation pattern for imidacloprid, fipronil, cypermethrin, sulfosulfuron, and control was 99, 98.5, 94, 91.67, and 7%, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis was used to determine the intermediate metabolites of cypermethrin with bacterial 1 B as 2-cyclopenten-1-one, 2-methylpyrrolidine, 2-oxonanone, 2-pentenoic acid, 2-penten-1-ol, hexadecanoic acid or palmitic acid, pentadecanoic acid, 3-cyclopentylpropionic acid, and 2-dimethyl. Furthermore, genes encoding aldehyde dehydrogenase (ALDH) and esterase were expressed under stress conditions and connected to pesticide bioremediation. Hence the efficacy of Bacillus brevis (1 B) could be employed for the bioremediation of pesticide mixtures and other toxic substances (dye, polyaromatic hydrocarbon, etc.) from contaminated sites.

Isolation and characterization of indigenous bacterial assemblage for biodegradation of persistent herbicides in the soil.

Extensive pesticides (herbicides) use is negatively disturbing the environment and humans. Pesticide bioremediation with eco-friendly techniques bears prime importance. This study aimed to isolate and characterize three different herbicides (metribuzin, clodinafop- propargyl, MCPA (2-methyl, 4 chlorophenoxyacetic acids) and Bromoxynil) degrading bacterial strains from agricultural fields of Punjab University, Pakistan. Among the 12 bacterial isolates, 5 were metribuzin degrading, 3 were clodinafop propargyl degrading and, 4 were MCPA and Bromoxynil degrading bacteria. Morphological, microscopic, and molecular characterization revealed that the majority of these bacterial strains were gram-negative and belonged to Bacillus and Pseudomonas genera. The isolates A6, B3, and C1 were subjected to respective herbicide degradation and the data was confirmed through GC-MS analysis. The effect of herbicide concentrations, pH, and temperature on bacterial growth was determined at OD600. The strain A6 degraded 14.8% metribuzin out of the provided concentration of 50 ppm by following the deamination pathway. While the isolates B3 and C1 degraded 23.2% and 33.9% clodinafop, MCPA and bromo-xynil, respectively, at a spiking concentration of 50ppm. The clodinafop, MCPA and Bromoxynil were metabolized into less toxic products i.e., dicarboxylic acids and 2-methyl phenol respectively, and metabolized via decarboxylation and dehalogenation mechanism. The present study evaluates the herbicides degrading bacterial strains that could potentially be used for bioremediation of agricultural contaminated sites.

Exploring the Potential of Composting for Bioremediation of Pesticides in Agricultural Sector

The rapid expansion of the human population has raised the chemical stress on the environment due to the increased demand of agricultural yields. The use of pesticides is the primary contributor to environmental chemical stress, which is essential for agricultural expansion in order to produce enough food to sustain the burgeoning human population. Pesticide residues in soil have grown to be a subject of rising concern as a result of their high soil retention and potential harm to unintended species. Diverse remediation strategies, such as physical, chemical, and biological, for limiting and getting rid of such contaminants have been put forth to deal with this problem. Bioremediation is one of these techniques, which has been deemed the best for reducing pollution because of its low environmental impact, simplicity of operation and construction. Microorganisms are implemented in this technique to break down and get rid of toxins in the environment or to reduce the toxicity of chemical compounds. This study thoroughly analyses the different composting soil remediation methods, including landfarming, biopiles, and windrows, to reduce and eliminate soil pollution. Although biological treatment is the best option for cleaning up polluted soil, it is still important to evaluate and review the approaches over the long term to determine whether they are effective in the field. It is because the reactivity of the microorganisms is highly dependent on environmental parameters, and the contemporary environment is characterised by unpredictable weather patterns, localised droughts, and temperature fluctuations.

Enhanced rice plant (BRRI-28) growth at lower doses of urea caused by diazinon mineralizing endophytic bacterial consortia and explorations of relevant regulatory genes in a Klebsiella sp. strain HSTU-F2D4R

Endophytic biostimulant with pesticide bioremediation activities may reduce agrochemicals application in rice cultivation. The present study evaluates diazinon-degrading endophytic bacteria, isolated from rice plants grown in the fields with pesticide amalgamation, leading to increased productivity in high-yielding rice plants. These endophytes showed capabilities of decomposing diazinon, confirmed by FT-IR spectra analysis. Growth promoting activities of these endophytes can be attributed to their abilities to produce an increased level of IAA content and to demonstrate high level ACC-deaminase activities. Furthermore, these endophytes demonstrated enhanced level of extracellular cellulase, xylanase, amylase, protease and lignin degrading activities. Five genera including Enterobacter, Pantoea, Shigella, Acinetobacter, and Serratia, are represented only by the leaves, while four genera such as Enterobacter, Escherichia, Kosakonia, and Pseudomonas are represented only by the shoots. Five genera including, Klebsiella, Enterobacter, Pseudomonas, Burkholderia, and Bacillus are represented only by the roots of rice plants. All these strains demonstrated cell wall hydrolytic enzyme activities, except pectinase. All treatments, either individual strains or consortia of strains, enhanced rice plant growth at germination, seedling, vegetative and reproductive stages. Among four (I-IV) consortia, consortium-III generated the maximum rice yield under 70% lower doses of urea compared to that of control (treated with only fertilizer). The decoded genome of Klebsiella sp. HSTU-F2D4R revealed nif-cluster, chemotaxis, phosphates, biofilm formation, and organophosphorus insecticide-degrading genes. Sufficient insecticide-degrading proteins belonging to strain HSTU-F2D4R had interacted with diazinon, confirmed in molecular docking and formed potential catalytic triads, suggesting the strains have bioremediation potential with biofertilizer applications in rice cultivation.

Deciphering the recent trends in pesticide bioremediation using genome editing and multi-omics approaches: a review.

Pesticide pollution in recent times has emerged as a grave environmental problem contaminating both aquatic and terrestrial ecosystems owing to their widespread use. Bioremediation using gene editing and system biology could be developed as an eco-friendly and proficient tool to remediate pesticide-contaminated sites due to its advantages and greater public acceptance over the physical and chemical methods. However, it is indispensable to understand the different aspects associated with microbial metabolism and their physiology for efficient pesticide remediation. Therefore, this review paper analyses the different gene editing tools and multi-omics methods in microbes to produce relevant evidence regarding genes, proteins and metabolites associated with pesticide remediation and the approaches to contend against pesticide-induced stress. We systematically discussed and analyzed the recent reports (2015-2022) on multi-omics methods for pesticide degradation to elucidate the mechanisms and the recent advances associated with the behaviour of microbes under diverse environmental conditions. This study envisages that CRISPR-Cas, ZFN and TALEN as gene editing tools utilizing Pseudomonas, Escherichia coli and Achromobacter sp. can be employed for remediation of chlorpyrifos, parathion-methyl, carbaryl, triphenyltin and triazophos by creating gRNA for expressing specific genes for the bioremediation. Similarly, systems biology accompanying multi-omics tactics revealed that microbial strains from Paenibacillus, Pseudomonas putida, Burkholderia cenocepacia, Rhodococcus sp. and Pencillium oxalicum are capable of degrading deltamethrin, p-nitrophenol, chlorimuron-ethyl and nicosulfuron. This review lends notable insights into the research gaps and provides potential solutions for pesticide remediation by using different microbe-assisted technologies. The inferences drawn from the current study will help researchers, ecologists, and decision-makers gain comprehensive knowledge of value and application of systems biology and gene editing in bioremediation assessments.

Effective Usage of Biochar and Microorganisms for the Removal of Heavy Metal Ions and Pesticides.

The bioremediation of heavy metal ions and pesticides is both cost-effective and environmentally friendly. Microbial remediation is considered superior to conventional abiotic remediation processes, due to its cost-effectiveness, decrement of biological and chemical sludge, selectivity toward specific metal ions, and high removal efficiency in dilute effluents. Immobilization technology using biochar as a carrier is one important approach for advancing microbial remediation. This article provides an overview of biochar-based materials, including their design and production strategies, physicochemical properties, and applications as adsorbents and support for microorganisms. Microorganisms that can cope with the various heavy metal ions and/or pesticides that enter the environment are also outlined in this review. Pesticide and heavy metal bioremediation can be influenced by microbial activity, pollutant bioavailability, and environmental factors, such as pH and temperature. Furthermore, by elucidating the interaction mechanisms, this paper summarizes the microbe-mediated remediation of heavy metals and pesticides. In this review, we also compile and discuss those works focusing on the study of various bioremediation strategies utilizing biochar and microorganisms and how the immobilized bacteria on biochar contribute to the improvement of bioremediation strategies. There is also a summary of the sources and harmful effects of pesticides and heavy metals. Finally, based on the research described above, this study outlines the future scope of this field.