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Enzymes secreted by white-rot fungi, such as laccase, offer a promising solution for treating xenobiotic compounds dangerous to the environment and human health. This study aimed to perform a comprehensive analysis of the tolerance of Pleurotus pulmonarius LBM 105 and its laccase activity toward the pesticides 2,4-D and chlorpyrifos both in vitro and in silico. The fungal strain was able to grow in different concentrations of the pesticides, showing evident morphological alterations. Laccase activity and a 53 kDa electromorph were present in all treatments, showing significant stability with peak activity achieved at a pH of 5.6 and within a temperature range of 50–60 °C. Three laccase genes were mapped, annotated, and characterized from the genome. PplacI obtained better structural validation and affinity energy of − 5.05 and − 7.65 kcal mol−1 with 2,4-D and chlorpyrifos, respectively. The Molecular Mechanics/Poisson-Boltzmann Surface Area analysis at 250 ns confirmed the docking results, revealing the existence of stronger hydrophobic interactions between laccase and chlorpyrifos and highlighting the importance of the Phe341 residue in stabilizing both complexes. Understanding the impact of pesticides on laccase's catalytic function is key to formulating and applying future biotechnological strategies with this enzyme. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is a prevalent groundwater contaminant detected worldwide, and microbes are sensitive indicators and initial responders to these chemical contaminants causing disturbances to their ecosystem. In this study, microbes isolated from San Marcos River sediment were screened for their TCE degradation potential. Among the twelve isolates (SAN1-12), five isolates demonstrated TCE degradation within 5 days at 25 °C and 40 mg/L of TCE concentration in the following order: SAN8 (87.56%), SAN1 (77.31%), SAN2 (76.58%), SAN3 (49.20%), and SAN7 (3.36%). On increasing the TCE concentration to 80 mg/L, the degradation efficiency of these isolates declined, although SAN8 remained the prominent TCE degrader with 75.67% degradation. The prominent TCE-degrading isolates were identified as Aeromonas sp. SAN1, Bacillus sp. SAN2, Gordonia sp. SAN3, and Bacillus proteolyticus SAN8 using 16S rRNA sequencing. The TCE degradation and cell biomass of Bacillus proteolyticus SAN8 were significantly improved when the incubation temperature was increased from 25 °C to 30 °C. However, both slightly acidic and alkaline pH levels, as well as higher TCE concentrations, lowered the efficacy of TCE degradation. Nevertheless, these conditions led to an increase in bacterial cell biomass. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are widespread, persistent, and toxic environmental pollutants. Many anthropogenic and some natural factors contribute to the spread and accumulation of PAHs in aquatic and soil systems. The effective and environmentally friendly remediation of these chemical compounds is an important and challenging problem that has kept scientists busy over the last few decades. This review briefly summarizes data on the main sources of PAHs, their toxicity to living organisms, and physical and chemical approaches to the remediation of PAHs. The basic idea behind existing approaches to the bioremediation of PAHs is outlined with an emphasis on a detailed description of the use of bacterial strains as individual isolates, consortia, or cell-free enzymatic agents. [ABSTRACT FROM AUTHOR]

The aim of this study was to measure consequences of the arsenic pollution released from a sewage treatment plant into the seawater in Jazan province in the southwest of Saudi Arabia. The impact of the release of arsenic on the ecosystem is the adsorption of arsenic by sea plants. To do so, samples were collected alongside a distance of seven kilometers from the treatment plant. The algae samples: Sargassum sp., Cladophora sp., and seagrasses: Halodule uninervis and Cymodocea rotunda were digested in nitric acid, and the assays of arsenic levels were taken by ICP-AES according to EPA methods. The results showed that algae are more efficient than seagrass with absorbing arsenic. Also, the treatment plant was not the only source of arsenic contamination, as ships and boats were adding more arsenic to the ecosystem.

Heavy metal and Persistent Organic Pollutants (POPs) pollution stemming from industrialization, intensive agriculture, and other human activities pose significant environmental and health threats. These contaminants persist in the air, soil, and water, particularly in industrialized nations, adversely affecting human health and ecosystems. While physical and chemical methods exist for detoxifying contaminated soil, they often have drawbacks such as high cost and technical complexity. Bioremediation, utilizing plants and microbes, offers a promising solution. Certain microorganisms like Streptomyces, Aspergillus and plant species such as Hibiscus and Helianthus show high metal adsorption capacities, making them suitable for bioremediation. However, plants' slow growth and limited remediation efficiency have been challenges. Recent advancements involve leveraging plant-associated microbes to enhance heavy metal removal. Additionally, nanotechnology, particularly nano-bioremediation, shows promise in efficiently removing contaminants from polluted environments by combining nanoparticles with bioremediation techniques. This review underscores bioremediation methods for heavy metals using plants and microbes, focusing on the role of Plant Growth Promoting Rhizobacteria (PGPR) in promoting phytoremediation. It also explores the implementation of nanotechnologies for eliminating metals from polluted soil, emphasizing the significance of soil microbiomes, nanoparticles, and contaminant interactions in developing effective nano-remediation strategies for optimizing agriculture in contaminated fields. [ABSTRACT FROM AUTHOR]

Coppe and zinc are priority pollutants in city soils. Copper and zinc are the limiting factors for lawn grasses. Cell selection can increase the resistance of lawn grasses to zinc and copper. The effect of zinc on the morphogenic ability of the callus was determined. The results of this study showed that zinc is less toxic to calli than copper. The method of obtaining lawn grass resistant to zinc has been developed. The results were used to develop the cell selection technology for obtaining plants resistant to the complex effect of zinc and copper. Concentrations of Copper (75 mg/l) and zinc (150 mg/L) were selected as selective. The author developed the cell selection scheme for obtaining plants resistant to the complex effect of Cu and Zn. The regenerants showed increased resistance to copper and zinc. [ABSTRACT FROM AUTHOR]

Synergistic properties usually produce combined effect greater than the sum of their separate effects. Hence, this paper assessed the synergistic effect of cow dung, goat droppings and poultry manure wastes for bioremediation of naphthalene, chrysene and pyrene in a crude oil-impacted soil at an experimental plot in a botanical garden, located at Abia State University, Nigeria, using appropriate standard methods. The result of the study showed about 96%, 93% and 90% removal of naphthalene, pyrene and chrysene respectively. This is in contrast with about <25% removal for the three contaminants using the natural attenuation method. It could also be seen that the amendment agents when combined performed better than when used singly, this shows that the combination of the animal manures has a synergistic effect on the removal of PAHs in a crude oil-impacted soil. The use of various animal wastes as supplements promotes microbial growth, accelerates the breakdown of contaminants, and improves soil fertility. In addition, combining multiple animal wastes produces a synergistic effect, leading to improved removal efficiency. This result highlights the potential of using a combination of animal wastes as an effective and sustainable strategy to remediate oil-contaminated PAH-contaminated soils. [ABSTRACT FROM AUTHOR]

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 plantassociated 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 nonpathogenic 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. [ABSTRACT FROM AUTHOR]

Three extremophile bacterial strains (BBCOL-009, BBCOL-014 and BBCOL-015), capable of degrading high concentrations of perchlorate at a range of pH (6.5 to 10.0), were isolated from Colombian Caribbean Coast sediments. Morphological features included Gram negative strain bacilli with sizes averaged of 1.75 × 0.95, 2.32 × 0.65 and 3.08 × 0.70 μm, respectively. The reported strains tolerate a wide range of pH (6.5 to 10.0); concentrations of NaCl (3.5 to 7.5% w/v) and KClO4− (250 to 10000 mg/L), reduction of KClO4− from 10 to 25%. LB broth with NaCl (3.5–30% w/v) and KClO4ˉ (250-10000 mg/L) were used in independent trials to evaluate susceptibility to salinity and perchlorate, respectively. Isolates increased their biomass at 7.5 % (w/v) NaCl with optimal development at 3.5 % NaCl. Subsequently, ClO4ˉ reduction was assessed using LB medium with 3.5% NaCl and 10000 mg/L ClO4ˉ. BBCOL-009, BBCOL-014 and BBCOL-015 achieved 10%, 17%, and 25% reduction of ClO4ˉ, respectively. The 16 S rRNA gene sequence grouped them as Bacillus flexus T6186-2, Bacillus marisflavi TF-11 (T), and Bacillus vietnamensis 15 − 1 (T) respectively, with < 97.5% homology. In addition, antimicrobial resistance to ertapenem, vancomycine, amoxicillin clavulanate, penicillin, and erythromycin was present in all the isolates, indicating their high adaptability to stressful environments. The isolated strains from marine sediments in Cartagena Bay, Colombia are suitable candidates to reduce perchlorate contamination in different environments. Although the primary focus of the study of perchlorate-reducing and resistant bacteria is in the ecological and agricultural realms, from an astrobiological perspective, perchlorate-resistant bacteria serve as models for astrobiological investigations. [ABSTRACT FROM AUTHOR]

Mining of organophosphorous (OPs)-degrading bacterial enzymes in collections of known bacterial strains and in natural biotopes are important research fields that lead to the isolation of novel OP-degrading enzymes. Then, implementation of strategies and methods of protein engineering and nanobiotechnology allow large-scale production of enzymes, displaying improved catalytic properties for medical uses and protection of the environment. For medical applications, the enzyme formulations must be stable in the bloodstream and upon storage and not susceptible to induce iatrogenic effects. This, in particular, includes the nanoencapsulation of bioscavengers of bacterial origin. In the application field of bioremediation, these enzymes play a crucial role in environmental cleanup by initiating the degradation of OPs, such as pesticides, in contaminated environments. In microbial cell configuration, these enzymes can break down chemical bonds of OPs and usually convert them into less toxic metabolites through a biotransformation process or contribute to their complete mineralization. In their purified state, they exhibit higher pollutant degradation efficiencies and the ability to operate under different environmental conditions. Thus, this review provides a clear overview of the current knowledge about applications of OP-reacting enzymes. It presents research works focusing on the use of these enzymes in various bioremediation strategies to mitigate environmental pollution and in medicine as alternative therapeutic means against OP poisoning. [ABSTRACT FROM AUTHOR]

The aim of this study was to measure consequences of the arsenic pollution released from a sewage treatment plant into the seawater in Jazan province in the southwest of Saudi Arabia. The impact of the release of arsenic on the ecosystem is the adsorption of arsenic by sea plants. To do so, samples were collected alongside a distance of seven kilometers from the treatment plant. The algae samples: Sargassum sp., Cladophora sp., and seagrasses: Halodule uninervis and Cymodocea rotunda were digested in nitric acid, and the assays of arsenic levels were taken by ICPAES according to EPA methods. The results showed that algae are more efficient than seagrass with absorbing arsenic. Also, the treatment plant was not the only source of arsenic contamination, as ships and boats were adding more arsenic to the ecosystem. [ABSTRACT FROM AUTHOR]

Bioremediation stands as a promising solution amid the escalating challenges posed by environmental pollution. Over the past 25 years, the influx of synthetic chemicals and hazardous contaminants into ecosystems has required innovative approaches for mitigation and restoration. The resilience of these compounds stems from their non-natural existence, distressing both human and environmental health. Microbes take center stage in this scenario, demonstrating their ability of biodegradation to catalyze environmental remediation. Currently, the scientific community supports a straight connection between biorefinery and bioremediation concepts to encourage circular bio/economy practices. This review aimed to give a pre-overview of the state of the art regarding the main microorganisms employed in bioremediation processes and the different bioremediation approaches applied. Moreover, focus has been given to the implementation of bioremediation as a novel approach to agro-industrial waste management, highlighting how it is possible to reduce environmental pollution while still obtaining value-added products with commercial value, meeting the goals of a circular bioeconomy. The main drawbacks and challenges regarding the feasibility of bioremediation were also reported. [ABSTRACT FROM AUTHOR]

Background: γ-Hexachlorocyclohexane (γ-HCH), an organochlorine insecticide of anthropogenic origin, is a persistent organic pollutant (POP) that causes environmental pollution concerns worldwide. Although many γ-HCH-degrading bacterial strains are available, inoculating them directly into γ-HCH-contaminated soil is ineffective because of the low survival rate of the exogenous bacteria. Another strategy for the bioremediation of γ-HCH involves the use of transgenic plants expressing bacterial enzyme for γ-HCH degradation through phytoremediation. Results: We generated transgenic Arabidopsis thaliana expressing γ-HCH dehydrochlroninase LinA from bacterium Sphingobium japonicum strain UT26. Among the transgenic Arabidopsis T2 lines, we obtained one line (A5) that expressed and accumulated LinA well. The A5-derived T3 plants showed higher tolerance to γ-HCH than the non-transformant control plants, indicating that γ-HCH is toxic for Arabidopsis thaliana and that this effect is relieved by LinA expression. The crude extract of the A5 plants showed γ-HCH degradation activity, and metabolites of γ-HCH produced by the LinA reaction were detected in the assay solution, indicating that the A5 plants accumulated the active LinA protein. In some A5 lines, the whole plant absorbed and degraded more than 99% of γ-HCH (10 ppm) in the liquid medium within 36 h. Conclusion: The transgenic Arabidopsis expressing active LinA absorbed and degraded γ-HCH in the liquid medium, indicating the high potential of LinA-expressing transgenic plants for the phytoremediation of environmental γ-HCH. This study marks a crucial step toward the practical use of transgenic plants for the phytoremediation of POPs. [ABSTRACT FROM AUTHOR]

Bioremediation using tropical marine algae provides cost effective and eco-friendly alternative mean of removing toxic and harmful substances from the environment. Bioremediation is an important tool in sustainable environmental management and protection. This study examined the productivity and bioremediation potential of Nannochloropsis oculata and Porphyridium cruentum in Water Soluble Fraction (WSF) of petroleum fuels by investigating the growth of Nannochloropsis oculata and Porphyridium cruentum at 0%, 10% 20% 30% 40% 50% 75% 100% of WSF of kerosene, diesel, and gasoline. Growth was monitored optically every two days for fourteen days using 721 Visible Spectrophotometer. Productivity was measured using prescribed procedure. Bioremediation potential of test algae were examined using standard method for the GC analysis of diesel range organics in 100% WSFs. The minimum growth for both species was recorded at 100% in all the fuels. The maximum growth of Porphyridium cruentum was obtained at 10% in all fuels, while the maximum growth of Nannochloropsis oculata was obtained at 30% in both kerosene and gasoline and at 50% in diesel. Whereas Porphyridium cruentum was greatly inhibited by all fuels, Nannochloropsis oculata was stimulated at lower concentration of the fuels. Nannochloropsis oculata proved more efficient for bioremediation of the petroleum fuels with 84.58%, 65.51% and 70.77% removal efficiency for kerosene, diesel and gasoline respectively, while Porphyridium cruentum was 58.94%, 46.64% and 56.67% respectively. Nannochloropsis oculata is a very strong and reliable candidate for bioremediation of petroleum hydrocarbons and should be subjected to further examination for sustainable and eco-friendly remediation of petroleum pollution. In this study, bioremediation of 100% Water Soluble Fraction (very high concentration) of the three most commonly used petroleum fuels (gasoline, diesel, kerosene) were examined. The bioremediation potential of the test algae were examined simultaneously in three petroleum fuels to enhance comparative assessment and to reduce the effect of environmental changes. This study identifies specific tropical marine alga that has high biomass productivity and bioremediation efficiency in tropical marine or coastal waters polluted with very high concentration of WSF of petroleum hydrocarbons. The result of this study is recommended for adoption by the bioremediation industries for the removal of high concentration of WSF of petroleum hydrocarbons in tropical marine waters and industrial waste waters. It may also be subjected to further examination. [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]

The superficial gas velocity (Ug) values of 1.0, 1.5 and 2.0 cm s−1 showed a diesel consumption of 59.70, 58.20 and 65.20 %, respectively. The productivity of the airlift bioreactors (ALBs) was 0.030, 0.026 and 0.034 g L−1 d−1, respectively. During 10 days of operation, the emulsification index (E24 %) values for Ug 1.0, 2.0 and 2.0 cm s−1 were 15.79, 15.07 and 12.85 %, respectively. Likewise, an increase in the degradation and suspended solids was observed when increasing the Ug from 1.0 to 2.0 cm s−1 of the ALBs, whereas a decrease in emulsification index E24 % was observed for an Ug of 2.0 cm s−1. According to the results, the Ug of 2.0 cm s−1 was the most effective for increasing the degradation of diesel and growth of the consortium among the Ug evaluated. Furthermore, the reduction of E24 % in this Ug suggests that the consortium uses a mixed form of hydrocarbon consumption, both by direct contact and in emulsified form. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is ubiquitous and an unessential trace element existing in the environment. Anthropogenic activities and applications of synthetic phosphate fertilizers greatly enhance the concentration of Cadmium in the environment, which proves to be carcinogenic. The long-term effects of heavy metals contamination on plants and animals have recently become a major public health concern. Thanks to the application of science and technology, new environmental initiatives can have a lower environmental impact significantly. The role of microbes is very well known and must be considered as potential pollutant removers. Microbial flora can remove heavy metals and oil from contaminated soil and water. In comparison to conventional techniques, bioremediation itself proved to be a more potent technique because the established mechanisms render it ineffective. Biotechnological advancements are inherently harmful to the environment because they have the potential to reduce metal pollution. Pollutants in the environment can be effectively removed using bioremediation. Both native and introduced species can thrive in a microorganism-friendly environment. [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]

Hydrocarbon contamination, including contamination with polycyclic aromatic hydrocarbons (PAHs), is a major concern in Antarctica due to the toxicity, recalcitrance and persistence of these compounds. Under the Antarctic Treaty, nonindigenous species are not permitted for use in bioremediation at polluted sites in the Antarctic region. In this study, three bacterial consortia (C13, C15, and C23) were isolated from Antarctic soils for phenanthrene degradation. All isolated bacterial consortia demonstrated phenanthrene degradation percentages ranging from 45 to 85% for 50 mg/L phenanthrene at 15 ℃ within 5 days. Furthermore, consortium C13 exhibited efficient phenanthrene degradation potential across a wide range of environmental conditions, including different temperature (4–30 ℃) and water availability (without polyethylene glycol (PEG) 6000 or 30% PEG 6000 (w/v)) conditions. Sequencing analysis of 16S rRNA genes revealed that Pseudomonas and Pseudarthrobacter were the dominant genera in the phenanthrene-degrading consortia. Moreover, six cultivable strains were isolated from these consortia, comprising four strains of Pseudomonas, one strain of Pseudarthrobacter, and one strain of Paeniglutamicibacter. These isolated strains exhibited the ability to degrade 50 mg/L phenanthrene, with degradation percentages ranging from 4 to 22% at 15 ℃ within 15 days. Additionally, the constructed consortia containing Pseudomonas spp. and Pseudarthrobacter sp. exhibited more effective phenanthrene degradation (43–52%) than did the individual strains. These results provide evidence that Pseudomonas and Pseudarthrobacter can be potential candidates for synergistic phenanthrene degradation at low temperatures. Overall, our study offers valuable information for the bioremediation of PAH contamination in Antarctic environments. [ABSTRACT FROM AUTHOR]

Glyphosate is a broad spectrum and non-selective herbicide employed to control different weeds in agricultural and urban zones and to facilitate the harvest of various crops. Currently, glyphosate-based formulations are the most employed herbicides in agriculture worldwide. Extensive use of glyphosate has been related to environmental pollution events and adverse effects on non-target organisms, including humans. Reducing the presence of glyphosate in the environment and its potential adverse effects requires the development of remediation and treatment alternatives. Bioremediation with microorganisms has been proposed as a feasible alternative for treating glyphosate pollution. The present study reports the glyphosate resistance profile and degradation capacity of the bacterial strain Burkholderia cenocepacia CEIB S5-2, isolated from an agricultural field in Morelos-México. According to the agar plates and the liquid media inhibition assays, the bacterial strain can resist glyphosate exposure at high concentrations, 2000 mg·L−1. In the degradation assays, the bacterial strain was capable of fast degrading glyphosate (50 mg·L−1) and the primary degradation metabolite aminomethylphosphonic acid (AMPA) in just eight hours. The analysis of the genomic data of B. cenocepacia CEIB S5-2 revealed the presence of genes that encode enzymes implicated in glyphosate biodegradation through the two metabolic pathways reported, sarcosine and AMPA. This investigation provides novel information about the potential of species of the genus Burkholderia in the degradation of the herbicide glyphosate and its main degradation metabolite (AMPA). Furthermore, the analysis of genomic information allowed us to propose for the first time a metabolic route related to the degradation of glyphosate in this bacterial group. According to the findings of this study, B. cenocepacia CEIB S5-2 displays a great glyphosate biodegradation capability and has the potential to be implemented in glyphosate bioremediation approaches. [ABSTRACT FROM AUTHOR]

The environmental pollution caused by petroleum hydrocarbons has received considerable attention in recent years. Microbial remediation has emerged as the preferred method for the degradation of petroleum hydrocarbons, which is experiencing rapid development driven by advancements in molecular biology. Herein, the capacity of different microorganisms used for crude oil bioremediation was reviewed. Moreover, factors influencing the effectiveness of microbial remediation were discussed. Microbial remediation methods, such as bioaugmentation, biostimulation, and bioventilation, are summarized in this review. Aerobic and anaerobic degradation mechanisms were reviewed to elucidate the metabolic pathways involved. The impacts of petroleum hydrocarbons on microorganisms and the environment were also revealed. A brief overview of synthetic biology and a unique perspective of technique combinations were presented to provide insight into research trends. The challenges and future outlook were also presented to stimulate contemplation of the mechanisms involved and the development of innovative techniques. [ABSTRACT FROM AUTHOR]

Underwater sensing has a wide range of applications including the location and monitoring of subsurface infrastructures such as cables and pipelines, mapping undersea terrain, the study of marine life, pollution and salinity monitoring and detection of seismic activities. Underwater sensing technologies are also essential to maritime surveillance, detection and tracking of submarines and other underwater objects. Using natural language processing and machine learning, we mined scientific publications to gain insight into underwater sensing research evolution during the 21st century, in terms of technology development and applications. This study offers a comprehensive analysis of the underwater sensing research landscape as well as the temporal evolution of its main research topics. We identified 18 key research topics that offer comprehensive and logical coverage of the research field. Nearly half of them are on a decreasing trend, despite an overall increase in the number of scientific publications. These findings and the extracted patterns can provide researchers and decision-makers with new insights into the field, its characteristics and its development. Our proposed algorithmic approach can also be applied to other areas for technologies of a disruptive nature. [ABSTRACT FROM AUTHOR]

Rapid economic development leads to environmental pollution with widespread pollutants including heavy metals, chemical particulates, untreated industrial sewage, and microplastics. Chromium production and its application had upsurged from past few decades and at present it had stretched up to 41 million metric tons globally. Chromium is one of the most mutagenic and carcinogenic pollutant, exposure to this heavy metal pollutants leads to respiratory, reproductive, cardiovascular diseases in humans and other harmful effects on plants and animals. Conventional methods for the treatment of hexavalent chromium from the environment includes ion-exchange, adsorption, solvent extraction, coagulation, electrodialysis and chemical precipitation. These methods are labor intensive, costly, and simultaneously release toxic components to the environment. Alternatively, bioremediation is one of the most effective biological processes which utilizes native microorganisms and plants to remove toxic metal pollutants from the polluted habitats. Bioremediation offers a sustainable technology for the management of heavy metal pollutants released from various mining and mineral processing industries and anthropogenic activities. This review gives a brief idea of hexavalent chromium pollution, its harmful effect on environment and humans, bioremediation through the application of native microorganisms and plants and describes the bioremediation method as a significant role for the sustainable management of pollutants. [ABSTRACT FROM AUTHOR]

Manganese (Mn) is an important micronutrient for many living organisms. As a cofactor of numerous enzymes, Mn² demonstrates enormous value to the human body, plants, and animals. Although, at high concentrations Mn² can become a threat for the health of living organisms and environment. Nowadays extensive employment of Mn² for various purpose leads to its excessive emission into the environment. Therefore, Mn element is usually found in wastewaters and drainages of various industries. Drinking water with high concentration of Mn² for a long time may causes problems with attention, memory, and motor skills. "Manganism" is a chronic neurological condition that can be caused by Mn² poisoning. The removal of Mn² is notoriously difficult due to the high stability of the Mn (II). This review first introduces the essentiality, natural and anthropogenic sources and the toxic effect of Mn² pollution, then sheds the light on its bioremediation. The bioremediation treatment of manganese-laden wastewater may include Mn (II) oxidation by various pathways. Bioremediation is a potential alternative for the remediation of Mn² metal pollutants from environments in an eco-friendly and cost-efficient manner through bacteria. This review study provides a scientific basis for the bioremediation of Mn pollutants through bacteria. This study may open an efficient new way to deal with the harmful condition of Mn² toxicity. [ABSTRACT FROM AUTHOR]

Metallic pollution in aquatic ecosystems has expanded dramatically due to the astonishing growth in industrial activity, posing a threat to the safety and health of the environment. Bacterial bioremediation offers promising solutions for decontaminating a polluted environment in a variety of situations. As a result, the tolerance and toxicity levels of the quaternary metal in bacteria isolated from the electroplating effluent were evaluated. The best tolerable strains were Bacillus megaterium, Sphingobacterium ginsenosidimutans, and Kocuria rhizophila, chosen for potential biosorption and bioaccumulation at high concentrations and maximum sorption rate and time. The mechanisms of bioremediation were verified by Scanning electron microscopy energy-dispersive x-ray analysis and Fourier transform infrared spectroscopy. The results showed that the maximum biosorption was 83.73% Ni and 75.49% quaternary during 6 h, while the Cu and Ni accumulation levels were 0.291 mg/g at 24 h and 0.159 mg/g at 12 h in B. megaterium,, respectively. The consortium achieved high biosorption with individual metals and quaternary ranging from 75.68 to 90.79%, and the highest accumulating amount of Cu was 0.399 mg/g during 12 h and 0.374 mg/g Ni during 6 h. During the exponential phase and using the bacterial consortium, the best metal bioremediation outcomes were found. It was observed that metal binding changes cell morphology and FTIR spectra identified the dominant groups involved in the biosorption of metals on the surfaces of bacteria. The study shed some light and offered more knowledge of the interactions of metal-tolerant bacteria during bioremediation processes and their practical applicability to mineral processing. [ABSTRACT FROM AUTHOR]

Synergistic properties usually produce combined effect greater than the sum of their separate effects. Hence, this paper assessed the synergistic effect of cow dung, goat droppings and poultry manure wastes for bioremediation of naphthalene, chrysene and pyrene in a crude oil-impacted soil at an experimental plot in a botanical garden, located at Abia State University, Nigeria, using appropriate standard methods. The result of the study showed about 96%, 93% and 90% removal of naphthalene, pyrene and chrysene respectively. This is in contrast with about

Trichloroethylene (TCE) is a prevalent groundwater contaminant detected worldwide, and microbes are sensitive indicators and initial responders to these chemical contaminants causing disturbances to their ecosystem. In this study, microbes isolated from San Marcos River sediment were screened for their TCE degradation potential. Among the twelve isolates (SAN1-12), five isolates demonstrated TCE degradation within 5 days at 25 °C and 40 mg/L of TCE concentration in the following order: SAN8 (87.56%), SAN1 (77.31%), SAN2 (76.58%), SAN3 (49.20%), and SAN7 (3.36%). On increasing the TCE concentration to 80 mg/L, the degradation efficiency of these isolates declined, although SAN8 remained the prominent TCE degrader with 75.67% degradation. The prominent TCE-degrading isolates were identified as Aeromonas sp. SAN1, Bacillus sp. SAN2, Gordonia sp. SAN3, and Bacillus proteolyticus SAN8 using 16S rRNA sequencing. The TCE degradation and cell biomass of Bacillus proteolyticus SAN8 were significantly improved when the incubation temperature was increased from 25 °C to 30 °C. However, both slightly acidic and alkaline pH levels, as well as higher TCE concentrations, lowered the efficacy of TCE degradation. Nevertheless, these conditions led to an increase in bacterial cell biomass.

Petroleum hydrocarbon (PH) pollution has mostly been caused by oil exploration, extraction, and transportation activities in colder regions, particularly in the Arctic and Antarctic regions, where it serves as a primary source of energy. Due to the resilience feature of nature, such polluted environments become the realized ecological niches for a wide community of psychrophilic hydrocarbonoclastic bacteria (PHcB). In contrast, to other psychrophilic species, PHcB is extremely cold-adapted and has unique characteristics that allow them to thrive in greater parts of the cold environment burdened with PHs. The stated group of bacteria in its ecological niche aids in the breakdown of litter, turnover of nutrients, cycling of carbon and nutrients, and bioremediation. Although such bacteria are the pioneers of harsh colder environments, their growth and distribution remain under the influence of various biotic and abiotic factors of the environment. The review discusses the prevalence of PHcB community in colder habitats, the metabolic processes involved in the biodegradation of PH, and the influence of biotic and abiotic stress factors. The existing understanding of the PH metabolism by PHcB offers confirmation of excellent enzymatic proficiency with high cold stability. The discovery of more flexible PH degrading strategies used by PHcB in colder environments could have a significant beneficial outcome on existing bioremediation technologies. Still, PHcB is least explored for other industrial and biotechnological applications as compared to non-PHcB psychrophiles. The present review highlights the pros and cons of the existing bioremediation technologies as well as the potential of different bioaugmentation processes for the effective removal of PH from the contaminated cold environment. Such research will not only serve to investigate the effects of pollution on the basic functional relationships that form the cold ecosystem but also to assess the efficacy of various remediation solutions for diverse settings and climatic conditions. [ABSTRACT FROM AUTHOR]

Bioremediation is a cost-effective and environmentally friendly technology that exploits the capabilities of microorganisms to degrade organic pollutants leading to complete mineralization. It has become the most preferred technique for oil spill remediation on soil in Nigeria. The study aims to examine the implication of particle sizes on bioremediation of crude oil polluted sandy soil in Okolomade part of Niger Delta Basin, southern Nigeria. Once a week samples were collected for a total of 28 days and were analyzed for chemical and microbial content in an aerobic setting. The classification of the soil samples was done according to the U.S. Bureau of soil classification system, the soil samples were divided into X and Y, where X represented fine to coarse sand and Y represented very fine to coarse sand. The particle size distribution, total hydrocarbon content (THC), total heterotrophic bacteria count (THBC), total organic carbon, soil pH, and available nitrogen and phosphorus were the parameters investigated throughout the 28-day examination of the soil samples. The results shows that the total heterotrophic bacterial count and soil pH increased in all of the soil samples, with samples A for fine to coarse sand (X) and sample E for very fine to coarse sand showing the most significant increase with values of 120 Cfu × 105/g and 266 Cfu × 105/g, respectively. These samples also had the lowest coefficients of uniformity (Cu). The results further reveal that the total hydrocarbons content, available nitrogen and phosphorus, as well as total organic carbon, all decreased noticeably. In contrast to samples with higher coefficient of uniformity values, samples with lower coefficients of uniformity showed a higher decrease in hydrocarbon content, suggesting that particle size distribution affects bioremediation. 0.0899 and 0.0942 were calculated to be the correlation coefficient of total hydrocarbon content vs coefficient of uniformity for fine to coarse sand (X) and very fine to coarse sand (Y). The contaminated soil samples are treated by combining pig manure, NPK 15:15:15, and the microorganism Pseudomonas aeruginosa, the total hydrocarbon content of sandy soil was reduced. [ABSTRACT FROM AUTHOR]

Important quantities of petroleum hydrocarbons are frequently spilled into the environment harming the environment, as well as human health. Furthermore, the interaction of petroleum hydrocarbons with the environment significantly disturbs the activity of the microorganisms, including bacteria that exist in petroleum hydrocarbons polluted environments. Using two different microbiological methods four groups of bacteria, such as heterotrophic, hydrocarbon-tolerant, hydrocarbon-degrading, as well as enterobacteria were detected in the analyzed samples collected from an old petroleum products storage. The detection of these bacteria, especially hydrocarbon-degrading, as well as hydrocarbon-tolerant bacteria was not unexpected since the concentration of the petroleum hydrocarbons in the analyzed samples was above the limit allowed by international environmental standards. Up to now, different treatment technologies have been developed to remove toxic hydrocarbons from environments contaminated with petroleum products. Therefore, because of the use of different remediation strategies, like bioremediations, the affected areas can be recovered and returned to their natural circuit. [ABSTRACT FROM AUTHOR]

Human activities lead to a large accumulation of heavy metals in the soil which comes from industrial activities such as mining smelting refining manufacturing processes and waste resulting from excessive use of chemical fertilizer and vehicle exhausts. So, soil pollutants especially with heavy metals can be treated using different types of plants; such as forest trees and grasses. These plants can tolerate soil pollutants at high concentrations in their biological tissue, and treat pollutants by absorbing and accumulating heavy metals in their living tissues. Therefore, in this article, we reviewed several forest tree species, that showed high resistance in the absorption and accumulation of heavy metals, such as genus Eucalyptus, Acacia, Salix, Populus, Tamarix, Melia, Dalbergia, Leucaena, Acer, Fraxinus, and Thuja. It has been noted that planting forest trees with high biomass that resist high concentrations of heavy metals in soil, works to rid the soil of these pollutants. This is the latest and best technology for treating soil pollution. In particular, it is unique from its counterparts in its environmental friendliness, economic benefits, and other returns resulting from plant cultivation. Therefore, applying phytoremediation techniques that benefit is the best and safest for the environment and living organisms. [ABSTRACT FROM AUTHOR]

Anthropogenic activities are increasing the amount of heavy metals and metalloids in the environment on a global scale, harming all living things and necessitating the employment of bioremediation procedures. Metal-resistant bacteria were used to clean polluted soil and promote plant growth; this approach has gained attention in recent years for bioremediation of heavy metal-contaminated systems. We studied the effects of chromium and lithium in Oryza sativa under controlled conditions. In the present study, lithium concentration was applied 50 ppm to 200 ppm according to the dose tolerance level, while the concentration of chromium was 10 ppm throughout the experimental setup due to its concentration observed up to 10 ppm in the targeted soil, which is present in Kasur area Punjab, Pakistan, for rice crop production in future perspective. The results reflect that plants with high lithium concentration have shown decreased plant growth and development, but due to bacterial presence, they thrived until harvesting stage. Due to increase in stress concentration up to 200 ppm, decline in plant growth was observed, but after bacterial inoculation, better growth was seen (chlorophyll content increased to 40, and panicle numbers were more than 13). Our findings reveal that lithium and chromium have a direct negative impact on Oryza sativa, which can be minimized by utilizing halophilic microbes (Klebsiella pneumonia and Enterobacter cloacae) through soil–plant system. [ABSTRACT FROM AUTHOR]

Microalgae have been increasingly used for wastewater treatment due to their capacity to assimilate nutrients. Samples of wastewater were taken from the Erbil wastewater channel near Dhahibha village. To investigate the role of algae in wastewater treatment algal samples were collected and used to isolate the most dominant and pollution tolerant algae such as Tetradesmus nygaardi cultures in BG11 broth and used for the treatment. Three doses (2, 1, and 0.2 g. l-1) of microalgae Tetradesmus nygaardi were applied for this experiment for 21 days, and samples were periodically (every 3 days) analyzed for physicochemical parameters such as pH, EC, phosphate, nitrate, and BOD5 using standard methods, in addition to, chlorophyll a determination. Results showed that the highest dose (2g.l-1) was the most effective for removing the highest rate of nutrients, which was confirmed statistically with significant differences (p=0.05) between all doses. Ammonium had the highest removal rate of 96 %, followed by NO3 at 95%, while BOD5 had a range of 82 to 89.5%. Results showed that the highest dose 2g.l-1 was the most effective dose for removing nutrients, confirmed by significant differences (p=0.05) between all doses. Reduced nutrient levels were accompanied by an increase in chlorophyll content, with the greatest biomass production of 1.03 mg. l-1 on the 17th day of the experiment. [ABSTRACT FROM AUTHOR]

Methyl orange (MO) is commonly used in the textile dyeing industry, posing serious health and environmental hazards due to its carcinogenic, mutagenic properties, and potential for bioaccumulation. Appropriate handling is needed to solve these problems by harnessing the capacity of living microorganisms and the adsorption properties of bentonite clay minerals. Although the conventional approach predominantly depends on free cells, recent study has developed other methods such as immobilization techniques. Therefore, this study aimed to investigate the efficiency of the immobilization matrix comprising sodium alginate (SA), polyvinyl alcohol (PVA), and bentonite by modifying Pseudomonas aeruginosa, Bacillus subtilis, and Ralstonia pickettii for MO removal of 50 mg/L. In the free cell technique, the results showed that the MO decreased to 43.13, 36.61, and 27.45% for each of the bacteria within 10 days at 35 °C. The bacterial immobilization technique, including live immobilized P. aeruginosa (LIPa), live immobilized B. subtilis (LIBs), and live immobilized R. pickettii (LIRp) beads also demonstrated significant efficiency, achieving MO removal rates up to 97.15, 95.65, and 66.63% within 10 days. These synthesized beads showed reusability, with LIPa, LIBs, and LIRp being used up to 4, 4, and 2 cycles, respectively. The external and internal surface conditions were observed using SEM instrument and the results showed that all components were agglomerated. Comparisons using dead bacterial biomass indicated that treatment with live bacteria consistently yielded significantly higher removal rates. These results showed the effectiveness of immobilized bacteria in MO removal, offering a promising potential in reducing pollutants.

Atrazine herbicide is known to disrupt the endocrine system and is potentially carcinogenic. Its continual application leads to high residue levels in soil, causing water pollution, which when consumed is associated with devastating health effects. This research reported the isolation and characterization of a new bacterial strains from active agricultural soil with the potential to biodegrade atrazine as a sole carbon source. An enrichment method was utilized to isolate the bacteria (A1, A2, B1, B2, C1 and C2) on mineral salt media (MSM) following serial dilution. Six isolates were screened for their tolerance to various concentrations of atrazine (500 to 1500 mg∙L‐1), and only isolate B1 tolerated up to 1500 mg∙L‐1 atrazine. The isolate was identified molecularly as Bacillus safensis strain BUK_BCH_BTE6 based on 16S rRNA gene sequencing and molecular phylogenetic analysis. Characterization of the isolate based on the effects of temperature, pH, substrate concentration, incubation time, inoculum size, and heavy metals revealed optimum growth and atrazine degradation at 35 °C, a pH of 7.5, 400 mg∙L‐1, at 48 h, and inoculum size of 600 µL, respectively. The growth of the isolate was inhibited by 2 ppm Hg, Cd, Cr, Pb, Ar, and Ni, while Fe, Cu, and Zn stimulated it. GC‐MS analysis revealed a degradation efficiency of 88.85% within 120 h, while metabolites such as desethyldeisopropylatrazine, deisopropylatrazine, N‐ethylammelide, and cyanuric acid were also detected. This isolate is a highly atrazine‐tolerant and efficient atrazine degrader that could be employed for bioremediation of atrazine‐polluted sites.

Abstract Rapid advances to industrialization and population increases have put aquatic ecosystems at high risk of pollution from various industrial and municipal effluents. The effluents consist of heavy metals (HM), micropollutants, nutrients, microorganisms, solids, particulates and dissolved matter. To this effect, pollutant remediation in such ecosystems is inevitable and of interest in global research. In this study, phycoremediation and its potential to bioremediate HM from polluted aqueous solutions is of focus. The factors influencing the process and the mechanisms involved are explored. The study established that available functional groups in microalgae, cell surfaces characteristics, type of microalgae species used, nutrient availability, size of biosorbent and metal concentration are some environmental factors, which influence phycoremediation success. Uptake of HM from contaminated water is regulated by mechanisms such as volatilization, bio-methylation, enzyme catalyzation, compartmentalization, extracellular polymeric substances-complexation, extracellular biosorption and intracellular bioaccumulation. To ensure high pollutant removal efficacy, improved adaptability of microalgae to HM-polluted systems and high resilience to attack by foreign agents, a number of mechanisms can be adopted. These include microalgal pretreatment with chemicals, bioengineering and biotechnological advances such a gene encoding, synthesis of transgenic proteins, gene overexpression, modification of microalgal cell surfaces with nanoparticles and the use of a consortium of microbes. This study noted that optimizing the discussed factors and mechanisms will promote field-scale application of phycoremediation in water treatment to remove HM.

Rapid increases in human populations and development has led to a significant exploitation of natural resources around the world. On the other hand, humans have come to terms with the consequences of their past mistakes and started to address current and future resource utilization challenges. Today's primary challenge is figuring out and implementing eco-friendly, inexpensive, and innovative solutions for conservation issues such as environmental pollution, carbon neutrality, and manufacturing effluent/wastewater treatment, along with xenobiotic contamination of the natural ecosystem. One of the most promising approaches to reduce the environmental contamination load is the utilization of algae for bioremediation. Owing to their significant biosorption capacity to deactivate hazardous chemicals, macro-/microalgae are among the primary microorganisms that can be utilized for phytoremediation as a safe method for curtailing environmental pollution. In recent years, the use of algae to overcome environmental problems has advanced technologically, such as through synthetic biology and high-throughput phenomics, which is increasing the likelihood of attaining sustainability. As the research progresses, there is a promise for a greener future and the preservation of healthy ecosystems by using algae. They might act as a valuable tool in creating new products. [ABSTRACT FROM AUTHOR]

Industrial wastewater causes water and soil pollution, leading to life-threatening issues. Wastewater comprises several dyes, detergents, phenols, chemical salts, and heavy metals which enhance temperature, pH, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) load, total suspended solids, Total Dissolved Solids (TDS), chlorides, sulfate, and nitrate of affected sites. Dye effluent is highly toxic and leads to mutagenic and carcinogenic outcomes on living beings. Environmental laws are being passed more frequently to control mostly azo-based dyes in the environment. The effluent must be treated before being discarded directly into the ecological ecosystem so that it can be reutilised and recycled for domestic purposes. In the present scenario, using a physicochemical-based approach is inefficient for eliminating contaminants as the process is expensive, and a secondary pollutant, sludge, is produced after the treatment. Being cheap and ecofriendly, the therapy of dye-laden water using microorganisms is a trend. The authors of the current review study have tried to bridge the gap in the bioremediation of dye wastewater. The review imparts an overview of the textile industry, the generation of wastewater by it, the environmental pollution caused, and its impact on the ecosystem. The discussion mainly focuses on the detailed analysis of the last few decades on the decolorisation efficiencies of numerous bioremediation techniques involved in treating textile dye effluent. Additionally, the authors have tried to include the most recent developments in this area. By using eco-friendly methods, this study will undoubtedly help dyestuff companies and researchers. [ABSTRACT FROM AUTHOR]