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Recently, there has been an increased effort to enhance the efficacy of phytoremediation of contaminated environments by exploiting plant–microbe interactions. The combined use of plants and endophytic bacteria is an emerging approach for the clean-up of soil and water polluted with organic compounds. In plant–endophyte partnerships, plants provide the habitat as well as nutrients to their associated endophytic bacteria. In response, endophytic bacteria with appropriate degradation pathways and metabolic activities enhance degradation of organic pollutants, and diminish phytotoxicity and evapotranspiration of organic pollutants. Moreover, endophytic bacteria possessing plant growth-promoting activities enhance the plant’s adaptation and growth in soil and water contaminated with organic pollutants. Overall, the application of endophytic bacteria gives new insights into novel protocols to improve phytoremediation efficiency. However, successful application of plant–endophyte partnerships for the clean-up of an environment contaminated with organic compounds depends on the abundance and activity of the degrading endophyte in different plant compartments. Although many endophytic bacteria have the potential to degrade organic pollutants and improve plant growth, their contribution to enhance phytoremediation efficiency is still underestimated. A better knowledge of plant–endophyte interactions could be utilized to increase the remediation of polluted soil environments and to protect the foodstuff by decreasing agrochemical residues in food crops. [ABSTRACT FROM AUTHOR]

Inoculation of plants with pollutant-degrading and plant growth-promoting microorganisms is a simple strategy to enhance phytoremediation activity. The objective of this study was to determine the effect of inoculation of different bacterial strains, possessing alkane-degradation and 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase activity, on plant growth and phytoremediation activity. Carpet grass(Axonopus affinis)was planted in soil spiked with diesel (1% w/w) for 90 days and inoculated with different bacterial strains,Pseudomonassp. ITRH25,Pantoeasp. BTRH79 andBurkholderiasp. PsJN, individually and in combination. Generally, bacterial application increased total numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere of carpet grass, plant biomass production, hydrocarbon degradation and reduced genotoxicity. Bacterial strains possessing different beneficial traits affect plant growth and phytoremediation activity in different ways. Maximum bacterial population, plant biomass production and hydrocarbon degradation were achieved when carpet grass was inoculated with a consortium of three strains. Enhanced plant biomass production and hydrocarbon degradation were associated with increased numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere of carpet grass. The present study revealed that the combined use of different bacterial strains, exhibiting different beneficial traits, is a highly effective strategy to improve plant growth and phytoremediation activity. [ABSTRACT FROM AUTHOR]

Plant-bacteria partnership is a promising strategy for the remediation of soil and water polluted with hydrocarbons. However, the limitation of major nutrients (N, P and K) in soil affects the survival and metabolic activity of plant associated bacteria. The objective of this study was to explore the effects of nutrients on survival and metabolic activity of an alkane degrading rhizo-bacterium. Annual ryegrass (Lolium multiflorum) was grown in diesel-contaminated soil and inoculated with an alkane degrading bacterium, Pantoea sp. strain BTRH79, in greenhouse experiments. Two levels of nutrients were applied and plant growth, hydrocarbon removal, and gene abundance and expression were determined after 100 days of sowing of ryegrass. Results obtained from these experiments showed that the bacterial inoculation improved plant growth and hydrocarbon degradation and these were further enhanced by nutrients application. Maximum plant biomass production and hydrocarbon mineralization was observed by the combined use of inoculum and higher level of nutrients. The presence of nutrients in soil enhanced the colonization and metabolic activity of the inoculated bacterium in the rhizosphere. The abundance and expression of CYP153 gene in the rhizosphere of ryegrass was found to be directly associated with the level of applied nutrients. Enhanced hydrocarbon degradation was associated with the population of the inoculum bacterium, the abundance and expression of CYP153 gene in the rhizosphere of ryegrass. It is thus concluded that the combination between vegetation, inoculation with pollutant-degrading bacteria and nutrients amendment was an efficient approach to reduce hydrocarbon contamination. [ABSTRACT FROM AUTHOR]

Abstract: Textile effluent is one of the main contributors of water pollution and it adversely affects fauna and flora. Constructed wetland is a promising approach to remediate the industrial effluent. The detoxification of industrial effluent in a constructed wetland system may be enhanced by applying beneficial bacteria that are able to degrade contaminants present in industrial effluent. The aim of this study was to evaluate the influence of inoculation of textile effluent-degrading endophytic bacteria on the detoxification of textile effluent in a vertical flow constructed wetland reactor. A wetland plant, Typha domingensis, was vegetated in reactor and inoculated with two endophytic bacterial strains, Microbacterium arborescens TYSI04 and Bacillus pumilus PIRI30. These strains possessed textile effluent-degrading and plant growth-promoting activities. Results indicated that bacterial inoculation improved plant growth, textile effluent degradation and mutagenicity reduction and were correlated with the population of textile effluent-degrading bacteria in the rhizosphere and endosphere of T. domingensis. Bacterial inoculation enhanced textile effluent-degrading bacterial population in rhizosphere, root and shoot of T. domingensis. Significant reductions in COD (79%), BOD (77%) TDS (59%) and TSS (27%) were observed by the combined use of plants and bacteria within 72 h. The resultant effluent meets the wastewater discharge standards of Pakistan and can be discharged into the environment without any risks. This study revealed that the combined use of plant and endophytic bacteria is one of the approaches to enhance textile effluent degradation in a constructed wetland system. [Copyright &y& Elsevier]

Abstract: Plant-endophyte partnership is a promising approach for remediation of soil contaminated with organic pollutants. Besides environmental conditions, the inoculation method can influence the survival and colonization of an applied microorganism and ultimately phytoremediation efficiency. It is therefore important to assess the efficiency of different inoculation methods and the persistence, colonization, and activity of an applied microorganism in different compartments of the plant and the contaminated soil like rhizosphere, root and shoot. The aim of this study was to assess whether inoculation mode affects survival and colonization, plant growth, and phytoremediation activity of the endophytic bacterium Burkholderia phytofirmans PsJN. Ryegrass was planted in diesel-contaminated soil and inoculated with B. phytofirmans PsJN by four methods: seed inoculation, soil inoculation, rhizosphere inoculation, and foliar inoculation. B. phytofirmans PsJN inoculation generally improved plant biomass production and hydrocarbon degradation. Among the four inoculation methods, soil inoculation was found to be the most efficient in improving plant biomass production, hydrocarbon degradation, and toxicity reduction. Enhanced plant growth, hydrocarbon degradation, and toxicity reduction were correlated with the population of the inoculated strain in the rhizo- and endosphere of the host plant. This study revealed that besides the plant-growth-promoting and pollutant-degrading activities of an inoculated strain, the inoculation procedure plays a vital role in determining the success of phytoremediation. [Copyright &y& Elsevier]

Abstract: Plant–bacteria partnership is a promising approach for remediating soil contaminated with organic pollutants. The colonization and metabolic activity of an inoculated microorganism depend not only on environmental conditions but also on the physiological condition of the applied microorganisms. This study assessed the influence of different inoculum pretreatments on survival, gene abundance and catabolic gene expression of an applied strain (Pantoea sp. strain BTRH79) in the rhizosphere of ryegrass vegetated in diesel contaminated soil. Maximum bacterium survival, gene abundance and expression were observed in the soil inoculated with bacterial cells that had been pregrown on complex medium, and hydrocarbon degradation and genotoxicity reduction were also high in this soil. These findings propose that use of complex media for growing plant inocula may enhance bacterial survival and colonization and subsequently the efficiency of pollutant degradation. [Copyright &y& Elsevier]

Abstract: Plant–bacteria partnerships have been extensively studied and applied to improve crop yield. In addition to their application in agriculture, a promising field to exploit plant–bacteria partnerships is the remediation of soil and water polluted with hydrocarbons. Application of effective plant–bacteria partnerships for the remediation of hydrocarbons depend mainly on the presence and metabolic activities of plant associated rhizo- and endophytic bacteria possessing specific genes required for the degradation of hydrocarbon pollutants. Plants and their associated bacteria interact with each other whereby plant supplies the bacteria with a special carbon source that stimulates the bacteria to degrade organic contaminants in the soil. In return, plant associated-bacteria can support their host plant to overcome contaminated-induced stress responses, and improve plant growth and development. In addition, plants further get benefits from their associated-bacteria possessing hydrocarbon-degradation potential, leading to enhanced hydrocarbon mineralization and lowering of both phytotoxicity and evapotranspiration of volatile hydrocarbons. A better understanding of plant–bacteria partnerships could be exploited to enhance the remediation of hydrocarbon contaminated soils in conjunction with sustainable production of non-food crops for biomass and biofuel production. [Copyright &y& Elsevier]

Abstract: The combined use of plants and associated microorganisms has great potential for cleaning up soils contaminated with petroleum hydrocarbons. Apart from environmental conditions the physicochemical properties of the soil are the main factors influencing the survival and activity of an inoculated strain as well as the growth of plants. This study examined the effect of different soil types (sandy, loamy sand and loam) on the survival, gene abundance and catabolic gene expression of two inoculated strains (Pseudomonas sp. strain ITRI53 and Pantoea sp. strain BTRH79) in the rhizosphere and shoot interior of Italian ryegrass vegetated in diesel contaminated soils. High colonization, gene abundance and expression in loamy soils were observed. By contrast, low colonization, gene abundance and absence of gene expression in sandy soil were found. The highest levels of genes expression and hydrocarbon degradation were seen in loamy soil that had been inoculated with BTRH79 and were significantly higher compared to those in other soils. A positive correlation was observed between gene expression and hydrocarbon degradation indicating that catabolic gene expression is necessary for contaminant degradation. These results suggest that soil type influences the bacterial colonization and microbial activities and subsequently the efficiency of contaminant degradation. [Copyright &y& Elsevier]

Plants in combination with microorganisms can remediate soils, which are contaminated with organic pollutants such as petroleum hydrocarbons. Inoculation of plants with degrading bacteria is one approach to improve remediation processes, but is often not successful due to the competition with resident microorganisms. It is therefore of high importance to address the persistence and colonization behavior of inoculant strains. The objective of this study was to determine whether the inoculation method (seed imbibement and soil inoculation) influences bacterial colonization, plant growth promotion and hydrocarbon degradation. Italian ryegrass was grown in non-sterilized soil polluted with diesel and inoculated with different alkane-degrading strains Pantoea sp. ITSI10, Pantoea sp. BTRH79 and Pseudomonas sp. MixRI75 individually as well as in combination. Inoculation generally had a beneficial effect on plant biomass production and hydrocarbon degradation, however, strains inoculated in soil performed better than applied by seed imbibement. Performance correlated with the colonization efficiency of the inoculated strains. The highest hydrocarbon degradation was observed in the treatment, in which all three strains were inoculated in combination into soil. Our study revealed that besides the degradation potential and competitive ability of inoculant strains the inoculation method plays an important role in determining the success of microbial inoculation. [ABSTRACT FROM AUTHOR]

Due to industrialization and urbanization, the use of detergents inadvertently led to contamination of aquatic environments, thus posing potential threat to aquatic organisms and human health. One of the main components of detergents is linear alkylbenzene sulfonate (LAS), which can cause toxic effects on living organisms, particularly aquatic life in the environment. In this study, floating treatment wetlands (FTWs) mesocosms were developed and augmented with LAS-degrading bacteria. The plant species, Brachiaria mutica (Para grass), was vegetated to establish FTWs and bacterial consortium (1:1:1:1) of Pseudomonas aeruginosa strain PJRS20, Bacillus sp. BRRH60, Acinetobacter sp. strain CYRH21, and Burkholderia phytofirmans Ps.JN was augmented (free or immobilized) in these mesocosms. Results revealed that the FTWs removed LAS from the contaminated water and their augmentation with bacteria slightly increased LAS removal during course of the experiment. Maximum reduction in LAS concentration (94%), chemical oxygen demand (91%), biochemical oxygen demand (93%), and total organic carbon (91%) was observed in the contaminated water having FTWs augmented with bacterial consortium immobilized on polystyrene sheet. This study highlights that the FTWs supported with immobilized bacteria on polystyrene sheets can provide an eco-friendly and sustainable solution for the remediation of LAS-bearing water, especially for developing countries like Pakistan. This pilot-scale study provided insights to resolve the detergent-contaminated wastewater issue, using floating treatment wetlands (FTWs) augmented with bacteria. The FTWs augmented with bacteria immobilized on a polystyrene sheet and vegetated with Brachiaria mutica led to high degradation of LAS, a toxic compound of detergent, from the contaminated water. [ABSTRACT FROM AUTHOR]

Abstract: Survival of every organism on earth depends on its interactions with other organisms. For example, animals form associations with the intestinal microflora, while plants develop symbiotic associations with neighboring plants, microflora, and microfauna. Most of the associations between plants and microorganisms are mediated by organic compounds released by the plant. The plant root system acts as a factory and exudes enormous amount of chemicals to effectively communicate with the surrounding soil organisms. Bacteria on roots and in the rhizosphere can also utilize these organic compounds as a source of nutrients and enhance their population size and metabolic activities. In return, plant-associated bacteria improve plant growth and development by different mechanisms including nitrogen fixation, provision of nutrients, and mediating resistance against pathogens. Although plant–bacterial partnerships have been found effective to enhance biomass production, their importance and relevance in agricultural systems are still underestimated. A better understanding of beneficial interactions between plant, soil, and bacteria could be exploited to improve growth and health of food and feed crops. Plant growth-promoting mechanisms of bacteria might enhance biomass production in a more sustainable manner, even on marginal land. Furthermore, plant growth-promoting and/or pollutant-degrading activities of bacteria could be exploited to improve the efficiency of phytoremediation of organic and inorganic pollutants from the soil and water or to protect the food chain by decreasing the concentrations of pollutants in food crops. [Copyright &y& Elsevier]

Soil contamination due to cadmium (Cd) is a ubiquitous environmental problem for which inexpensive remediation alternatives are required. Phytoaccumulation, the use of plants to extract and accumulate heavy metals from the contaminated environment, is such an alternative. In this study, we aimed at establishing effective plant-bacteria interplay between Brachiaria mutica and Cd-resistant endophytic bacteria eventually leading to improved phytoremediation. B. mutica was grown in a Cd-contaminated soil and inoculated with three Cd-tolerant endophytic bacteria individually as well as in combination. Plant physiological parameters, biomass production, bacterial colonization, and Cd-accumulation were observed at four different Cd exposures, i.e., 100, 200, 400 and 1000 mg kg−1 of soil. The combined application of endophytic bacteria was more effective as compared to their individual applications at all concentrations. Nevertheless, highest performance of consortium was seen at 100 mg Cd kg−1 of soil, i.e., root length was enhanced by 46%, shoot length by 62%, chlorophyll content by 40%, and dry biomass by 64%; which was reduced with the increase in Cd concentration. The bacterial population was highest in the root interior followed by rhizosphere and shoot interior. Concomitantly, plants inoculated with bacterial consortium displayed more Cd-accumulation in the roots (95%), shoots (55%), and leaves (44%). Higher values of BCFroot (> 1), and lower values for BCFshoot and TF (< 1) indicates capability of B. mutica to accumulate high amounts of Cd in the roots as compared to the aerial parts. The present study concludes that plant-endophyte interplay could be a sustainable and effective strategy for Cd removal from the contaminated soils. [ABSTRACT FROM AUTHOR]

Floating treatment wetlands (FTWs) are an innovative product of ecological engineering that can play a promising role in wastewater treatment. It provides low-cost, eco-friendly, and sustainable solutions for the treatment of wastewater, particularly in regions with economic constraints. Generally, FTWs comprise rooted plants that grow on the surface of water with their roots extending down into the pelagic zone rather than being embedded into the sediments. This drooping structure helps develop (1) a hydraulic flow between the root network and the bottom of the treatment system and (2) a large biologically active surface area for the physical entrapment (filtration) of contaminants, as well as their biochemical transformation and degradation. Furthermore, the rooted network allows proliferation of microorganisms that form biofilms and enhance pollutant degradation while promoting plant growth. The augmentation of bacteria in FTWs has been proven to be the most effective approach for reclamation of wastewater. This article discusses the operational parameters of FTWs for maximal remediation of wastewater and highlights the importance of plant-bacteria partnerships in a typical FTW system for enhanced cleanup of wastewater. We propose that this technology is preferable over other methods that require high energy, costs, and area to install or operate machinery. [ABSTRACT FROM AUTHOR]

Fabric bleaching is one of the most widely used processes of the textile industry that also produces a significant amount of highly polluted wastewater. Previously, expensive and chemically extensive conventional remediation systems were used to treat bleaching effluent. Despite this, the potential of constructed wetlands (CWs) as a treatment system remains un-investigated. Furthermore, most research on the use of CWs for textile effluents are conducted at laboratory scale and therefore further research at field-scale is timely. This study compares the efficacy of bacterial augmented vertical flow constructed wetlands (VFCWs) and horizontal flow constructed wetlands (HFCWs) for the remediation of textile bleaching wastewater at pilot scale. To this end, CWs macrocosms of 1000 L water capacity were planted with Phragmites australis and inoculated with bacterial strains possessing pollutant degradation and plant growth-promoting traits. The results showed that both variants of CWs were effective in attenuating pollutants from the wastewater; however, the performance of HFCWs exceeded that of the VFCWs for almost every pollutant measure undertaken. For HFCWs, a significant reduction in COD (89%), BOD (91%), TOC (96%), and toxicity was achieved in a period of 72 h during the first month of operation. Bacterial inoculation in CWs further improved the system's performance and these bacteria also exhibited persistence in the rhizoplane (43%), root interior (56%) and shoot interior (29%) of P. australis. This study, therefore, suggests that the bacterial augmented HFCWs is a suitable approach for industrial scale textile bleach wastewater treatment. Unlabelled Image • Pilot-scale remediation of textile bleaching effluent was carried out via constructed wetlands. • The performance of HFCWs was better than the VFCWs. • Augmentation of bacterial endophytes further enhanced remediation in both wetland variants. • This study is step forward to the field-scale application of endophyte-assisted CWs. [ABSTRACT FROM AUTHOR]

Abstract A pilot-scale vertical flow constructed wetland (VFCWs) system was designed, implemented and operated for one year for the treatment of dye-rich real textile effluent. Brachiaria mutica was vegetated to develop VFCWs in which five different textile effluent degrading endophytic bacteria were inoculated. These bacteria were screened based on their dye degrading and plant growth promoting capabilities. The system's performance was evaluated by monitoring physicochemical parameters, nutrients removal, heavy metals reduction, detoxification potential, and persistence of endophytic bacteria in the plant rhizo- and endosphere. Although VFCWs were able to remove a majority of the pollutants from the wastewater, bacterial augmentation further enhanced the remediation efficiency. The system promoted an increase in dissolved oxygen up to 188% and, concomitantly, a substantial decrease in the chemical oxygen demand (81%), biochemical oxygen demand (72%), total dissolved solids (32%), color (74%), nitrogen (84%), phosphorous (79%), and heavy metals [Cr(97%), Fe(89%), Ni(88%), Cd(72%)] was recorded. Wastewater treated with VFCWs augmented with bacteria was found to be non-toxic and inoculated bacteria showed persistence in the root and shoot interior of B. mutica. Conclusively, VFCWs proved to be an effective methodology for treatment of textile effluent whereas its smaller size with high efficiency is an advantage for field-scale applications. Graphical abstract Unlabelled Image Highlights • A pilot-scale endophyte-assisted VFCWs were engineered to treat real textile effluent. • Endophytes augmentation increased removal of organic and inorganic pollutants. • Inoculated bacteria displayed persistence in the root and shoot of Brachiaria mutica. • This study recommends field-scale application of endophyte-assisted phytoremediation. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) have emerged as cost-effective and sustainable treatment systems for the remediation of industrial wastewaters; nevertheless, their potential has mostly been evaluated in laboratory-scale studies. Likewise, endophytic bacteria can enhance plant growth and reduce phytotoxicity under polluted conditions, but their application with pilot-scale CWs has rarely been evaluated. The present study aims to evaluate on-site performance of endophyte-assisted pilot-scale horizontal flow constructed wetlands (HFCWs) for the remediation of effluent from a textile industry. The HFCWs were established by planting Leptochloa fusca in the presence of three endophytic bacterial strains with dye degrading, and plant growth promoting capabilities. We found that the system was able to remove a significant proportion of both organic and inorganic pollutants. Maximum reduction of pollutants was observed in endophyte-augmented HFCWs, where the COD and BOD reduced from 493 to 70 mg l −1 and 190 to 42 mg l −1 , respectively, within 48 h. Additionally, survival of endophytic bacteria in different components of the HFCWs was also recorded. Treated wastewater was found to be non-toxic and the inoculated bacteria showed persistence in the wastewater as well as rhizo- and endosphere of L. fusca . Accordingly, a positive impact on plant growth was observed in the presence of bacterial augmentation. The system performance was comparable to the vertical flow constructed wetlands (VFCWs) as high nutrients reduction was seen in the presence of this partnership. This pilot-scale study is a step forward toward the field-scale application of phytoremediation coupled with bacterial endophytes as a cost-effective means of on-site wastewater remediation. To the best of our knowledge, this is among the first pilot-scale studies on use of HFCWs for improvement in quality of textile industry effluent as most previous studies are limited either in the context of engineering or lack effective interplay of plant and bacteria. [ABSTRACT FROM AUTHOR]

Phenol is a commonly found organic pollutant in industrial wastewaters. Its ecotoxicological significance is well known and, therefore, the compound is often required to be removed prior to discharge. In this study, plant-bacterial synergism was established in floating treatment wetlands (FTWs) in an attempt to maximize the removal of phenol from contaminated water. A common wetland plant, Typha domingensis, was vegetated on a floating mat and augmented with three phenol-degrading bacterial strains, Acinetobacter lwofii ACRH76, Bacillus cereus LORH97, and Pseudomonas sp. LCRH90, to develop FTWs for the remediation of water contaminated with phenol. All of the strains are known to have phenol-reducing properties, and grow well in FTWs. Results showed that T. domingensis was able to remove a small amount of phenol from the contaminated water; however, bacterial augmentation enhanced the removal potential significantly, i.e., 0.146 g/m2/day vs. 0.166 g/m2/day, respectively. Plant biomass also increased in the presence of bacterial consortia; and inoculated bacteria displayed successful colonization/survival in the rhizosphere, root interior and shoot interior of the plant. Similarly, highest reduction in chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and total organic carbon (TOC) was achieved by the combined application of plants and bacteria. The study demonstrates that the plant-bacterial synergism in a FTW may be a more effective approach for the remediation of phenol-contaminated water. [ABSTRACT FROM AUTHOR]

Phytoremediation is a promising approach for the cleanup of soil contaminated with petroleum hydrocarbons. This study aimed to develop plant-bacterial synergism for the successful remediation of crude oil-contaminated soil. A consortia of three endophytic bacteria was augmented to two grasses, Leptochloa fusca and Brachiaria mutica, grown in oil-contaminated soil (46.8 g oil kg−1 soil) in the vicinity of an oil exploration and production company. Endophytes augmentation improved plant growth, crude oil degradation, and soil health. Maximum oil degradation (80%) was achieved with B. mutica plants augmented with the endophytes and it was significantly (P < 0.05) higher than the use of plants or bacteria individually. Moreover, endophytes showed more persistence, the abundance and expression of alkB gene in the rhizosphere as well as in the endosphere of the tested plants than in unvegetated soil. A positive relationship (r = 0.70) observed between gene expression and crude oil reduction indicates that catabolic gene expression is important for hydrocarbon mineralization. This investigation showed that the use of endophytes with appropriate plant is an effective strategy for the cleanup of oil-contaminated soil under field conditions. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the potential of plant-bacterial synergism in floating treatment wetlands (FTWs) for efficient remediation of an oil field wastewater. Two plants, Brachiara mutica and Phragmites australis , were vegetated on floatable mats to develop FTWs, and inoculated with bacterial cons which were then inoculated with a consortium of hydrocarbon-degrading bacteria ( Bacillus subtilis strain LORI66, Klebsiella sp . strain LCRI87, Acinetobacter Junii strain TYRH47, Acinetobacter sp . strain LCRH81). Both plants successfully removed organic and inorganic pollutants from wastewater, but bioaugmentation of P. australis significantly enhanced the plant’s efficiency to reduce oil content (97%), COD (93%), and BOD (97%), in wastewater. Analysis of alkane-degrading gene ( alkB ) abundance and its expression profile further validated a higher microbial growth and degradation activity in water around P. australis as well as its roots and shoots. This study provides insight into the available phytotechnology for remediation of crude oil-contaminated water and introduces a wetland macrophyte, P. australis, with tailor-made bacterial consortium as an effective tool for improved phytoremediation efficiency of FTWs. [ABSTRACT FROM AUTHOR]

For effective remediation of contaminants, plant-endophyte partnership is a promising field to be explored. Generally endophytic bacteria assist their host plant by withstanding the stress induced by the contaminants. The objective of this study was to explore the suitability of plant-bacterial partnership for chlorpyrifos (CP) remediation using ryegrass and a CP degrading endophyte,Mesorhizobiumsp. HN3 which belongs to plant growth promoting rhizobia. The inoculatedyfp-taggedMesorhizobiumsp. HN3 efficiently colonized in the rhizosphere, enhanced plant growth and degradation of CP and its metabolite 3,5,6 trichloro-2-pyridinol (TCP). Significantly lower CP residues were observed in the roots and shoots of plants vegetated in inoculated soil which might be attributed to the efficient root colonization of HN3yfp. These results suggest the involvement ofMesorhizobiumsp. HN3yfpin CP degradation inside the roots and rhizosphere of plants and further emphasize on the effectiveness of endophytic bacteria in stimulating the remediation of pesticide contaminants. This is the first report which demonstrates the efficacy of bacterial endophyte for degradation of CP residues taken up by the plant and enhanced remediation of chlorpyrifos contaminated soil. [ABSTRACT FROM AUTHOR]

The use of floating treatment wetlands (FTWs) is a promising approach for the remediation of sewage effluent. The efficiency of FTWs can be improved by the combined use of plants and pollutant-degrading bacteria. The aim of this study was to evaluate the influence of inoculation of endophytic bacteria on the detoxification of sewage effluent in FTWs. A terrestrial plant, Brachiaria mutica , was vegetated on a floating mat and inoculated with three endophytic bacterial strains, Acinetobacter sp. strain BRSI56, Bacillus cereus strain BRSI57, and Bacillus licheniformis strain BRSI58, to develop FTWs for the remediation of sewage effluent of Faisalabad city (Pakistan). Results indicated that B. mutica has the potential to remove both organic and inorganic contaminants from sewage effluent. However, endophytic inoculation in FTWs further enhanced the removal efficiency. Maximum reduction in chemical oxygen demand (COD), biochemical oxygen demand (BOD 5 ), total nitrogen (N), and phosphate (PO 4 ) was achieved by the combined use of plants and bacteria. Moreover, the inoculated bacteria showed persistence in water as well as colonization in the root and shoot of the plant. Treated effluent met the national wastewater discharge standards of Pakistan and can be discharged in the environment without any environmental risks. This study provides useful evidence of endophyte-assisted FTWs to be the most sustainable and affordable approach for in situ remediation of sewage effluent. [ABSTRACT FROM AUTHOR]

[Display omitted] • A land-free cultivation system was employed to produce Para grass biomass. • The biomass was pyrolyzed at four heating rates. • The pyrolytic properties and products were compared with the biomass produced on soil. • Wastewater cultivation made the biomass suitable for pyrolysis. • Industrial wastewater cultivation improved the pyrolysis parameters and products. Producing biomass as a renewable bioenergy feedstock is challenging due to scarcity of agricultural lands. In the present study, a land-free cultivation system was employed to produce the Para grass biomass using industrial and urban wastewaters as growth media. The biomass was pyrolyzed at four different heating rates (10 °C min−1, 20 °C min−1, 30 °C min−1, 40 °C min−1) under an inert environment. The pyrolysis data were analyzed using three isoconversional models namely Flynn-Wall-Ozawa (FWO), Kissenger-Akahira-Sunose (KAS), and Starink. The pyrolysis of both samples occurred in three stages, while major pyrolysis occurred during the second stage (200–400 °C) at the corresponding conversion points (α) ranging from 0.20 to 0.65. The high heating values (HHV) of the biomasses produced on wastewaters were shown to be 18.85 MJKg−1 and 18.14 MJKg−1, respectively. The activation energies ranged from 136.45 to 149.18 kJmol−1, 133.35–146.71 kJmol−1, 133.85–147.23 kJmol−1 estimated through for FWO, KAS, and Starink methods, respectively. Pre-exponential factors showed the first order reaction kinetics and a lower difference (<5 KJmol−1) between the enthalpy change and activation energy (E a) values indicated the favorable reaction thermodynamics. The pyrolytic gases mainly contained hydrocarbons, aromatics, alcohols, phenols, ketones, aldehydes, carboxylic acids, and esters. Interestingly, the wastewater cultivation improved HHV of the biomasses, lowered the E a -values, and made the pyrolysis more energy efficient, and this improvement was more obvious for industrial wastewater cultivation. Hence, employing a land-free cultivation system could be a novel and promising approach to produce renewable biomass with improved pyrolysis potential to fuel the future while keeping the energy-water-environment nexus sustainable. [ABSTRACT FROM AUTHOR]