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Recent studies indicate that while unfunctionalized carbon nanomaterials (CNMs) exhibit very low decomposition rates in soils, even minor surface functionalization (e.g., as a result of photochemical weathering) may accelerate microbial decay. We present results from a C 60 fullerene-soil incubation study designed to investigate the potential links between photochemical and microbial degradation of photo-irradiated C 60 . Irradiating aqueous 13 C-labeled C 60 with solar-wavelength light resulted in a complex mixture of intermediate products with decreased aromaticity. Although addition of irradiated C 60 to soil microcosms had little effect on net soil respiration, excess 13 C in the respired CO 2 demonstrates that photo-irradiating C 60 enhanced its degradation in soil, with ∼0.78% of 60 day photo-irradiated C 60 mineralized. Community analysis by DGGE found that soil microbial community structure was altered and depended on the photo-treatment duration. These findings demonstrate how abiotic and biotic transformation processes can couple to influence degradation of CNMs in the natural environment. [ABSTRACT FROM AUTHOR]

The pollutants can enter water bodies at various point and non-point sources, and wastewater discharge remains a major pathway. Wastewater treatment effectively reduces contaminants, it is expensive and requires an eco-friendly and sustainable alternative approach to reduce treatment costs. Algae have recently emerged as a potentially cost-effective method to remediate toxic pollutants through the mechanism of biosorption, bioaccumulation, and intracellular degradation. Hence, before discharging the wastewater into the natural environment better solutions for environmental resource recovery and sustainable developments can be applied. More importantly, algae are a potential feedstock material for various industrial applications such as biofuel production. Currently, researchers are developing algae as a source for pharmaceuticals, biofuels, food additives, and bio-fertilizers. This review mainly focused on the potential of algae and their specific mechanisms involved in wastewater treatment and energy recovery systems leading to important industrial precursors. The review is highly beneficial for scientists, wastewater treatment plant operators, freshwater managers, and industrial communities to support the sustainable development of natural resources. [Display omitted] • Algae have the potential for wastewater treatment and pollutants remediation. • Algal cultures produce biomass from the wastewater pollutants. • The algal biomass can be used for the fractionation of value-added products. • Potential algae can be used for resource recovery and sustainability. [ABSTRACT FROM AUTHOR]

To better protect consumers from exposure to produce contaminated with Escherichia coli, the potential transfer of E. coli from manure or irrigation water to plants must be better understood. We used E. coli strains expressing bioluminescence (E. coli O157:H7 lux) or multiantibiotic resistance (E. coli2+) in this study. These marked strains enabled us to visualize in situ rhizosphere colonization and metabolic activity and to track the occurrence and survival of E. coli in soil, rhizosphere, and phyllosphere. When radish and lettuce seeds were treated with E. coli O157:H7 lux and grown in an agar-based growth system, rapid bacterial colonization of the germinating seedlings and high levels of microbial activity were seen. Introduction of E. coli2+ to soil via manure or via manure in irrigation water showed that E. coli could establish itself in the lettuce rhizosphere. Regardless of introduction method, 15 days subsequent to its establishment in the rhizosphere, E. coli2+ was detected on the phyllosphere of lettuce at an average number of 2.5 log CFU/g. When E. coli2+ was introduced 17 and 32 days postseeding to untreated soil (rather than the plant surface) via irrigation, it was detected at low levels (1.4 log CFU/g) on the lettuce phyllosphere 10 days later. While E. coli2+ persisted in the bulk and rhizosphere soil throughout the study period (day 41), it was not detected on the external portions of the phyllosphere after 27 days. Overall, we find that E. coli is mobile in the plant system and responds to the rhizosphere like other bacteria. [ABSTRACT FROM AUTHOR]

The impact of the fungicide chlorothalonil on dominant bacterial and fungal populations following application to turfgrass, forest, and agricultural soils was investigated. Chlorothalonil was applied to each soil at three rates, representing 0.2, 1 and 5 times the recommended label rate for turfgrass, and incubated for a 2-week period. Changes to the microbial community caused by the chlorothalonil application were assessed following DNA extraction, PCR-amplification using both bacteria domain- and fungal-specific primers, then separation with denaturing gradient gel electrophoresis (DGGE). Digitized DGGE images were used to determine two parameters: the number of bands per lane and the Shannon–Wiener index of diversity (H′), both of which were used only for comparison of the different treatments, and not as true diversity measurements. Bands appearing to be either enhanced or inhibited as a result of the chlorothalonil treatment were excised and sequenced. Increased rates of chlorothalonil impacted eight bacterial populations (two inhibitions, four enhancements, and two non-specific responses) and four fungal populations (all inhibitions). Band number and H′ indicated an altered but not significantly different (P<0.05) bacterial and fungal community structure following chlorothalonil application. Sequencing of excised DGGE bands indicated an impact on several groups of bacteria (Cytophaga–Flavobacterium–Bacteroides, α-, β-, γ-, and δ-proteobacteria) and two fungal taxa (zygomycota and ascomycota). Although changes to the overall community structure of dominant species were non-significant, we conclude that following a single chlorothalonil application and a short incubation period, community changes including both enhancement and inhibition of a variety of dominant organisms can occur. [Copyright &y& Elsevier]

Abstract: Aerobic biodegradation of 8:2 fluorotelomer stearate (FTS) and 8:2 fluorotelomer citrate triester (TBC) was evaluated in a forest soil in closed bottle microcosms. Loss of parent, production of 8:2 fluorotelomer alcohol (8:2 FTOH), which is released along with stearic acid (SA) by microbial ester linkage, and subsequent metabolites from FTOH degradation were monitored for up to 7months. Soil microcosms were extracted with ethyl acetate followed by two heated 90/10 v/v acetonitrile/200mM NaOH extractions. Cleavage of the ester linkage in the 8:2 FTS occurred (t 1/2 ∼28d), producing 8:2 FTOH and various levels of subsequent metabolites. Quantifying the generation of SA from ester cleavage in FTS was complicated by the natural production and degradation of SA in soil, which was probed in an additional FTS and SA study with the same soil that had been stored at 4°C for 12months. In the latter study, FTS degraded faster (t 1/2 ∼5d) such that SA production well above soil background levels was clearly observed along with rapid subsequent SA degradation. Cold storage was hypothesized to enrich fungal enzymes, which are known to be effective at hydrolytic cleavage. 8:2 TBC biotransformation was slow, but evident with the production of PFOA well above levels expected from known FTOH residuals. Slower degradation of TBC compared to FTS is likely due to steric hindrances arising from the close proximity of three 8:2 FT chains on the citrate backbone limiting the enzyme access. [Copyright &y& Elsevier]

Egg-washing wastewater contains a high concentration of nutrition and organic matter since eggs are broken during the washing and cleaning processes. Moreover, the wastewater contains small amounts of detergents or sanitizing agents. These contaminants may pose environmental challenges when they are not properly managed or treated. The study scrutinizes the efficiency of electrocoagulation (EO) and electrooxidation (EO) approaches for egg-wash wastewater treatment. The response surface methodology was employed to optimize the operational parameters. The removal efficiencies of soluble chemical oxygen demand (sCOD 90%), ammonia (NH 3 –N 91%), nitrate (NO 3 −-N 97%), nitrite (NO 2 −-N 89.3%), total dissolved nitrogen (TDN 91%), and phosphate (90%) were measured under various treatment conditions. The optimum treatment conditions achieved in the combined EC + EO process were pH 6.0, current density 20 mA cm−2, and electrolysis time of 60 min, respectively. Degradation kinetics of the egg-wash pollutants showed a significant reduction in half-life (t 1/2) with EO (after EC-Aluminum) at 15 min, 12 min, 17 min, and 15 min for sCOD, NO 2 −-N. NO 3 −-N, and TDN, respectively. Whereas the half-life of NH 3 –N (18 min) and phosphate (17 min) reduced significantly with the EO (after EC-iron). Al and Fe electrodes coupled with boron-doped diamond were found efficient for pollutant removal. Environmental implication. Egg-wash wastewater has a high protein content and contains nutrients that are essential for living organisms. While these compounds can be valuable for agricultural use by increasing soil phosphate concentration, they can also become an issue if the excess nutrients are not properly managed. The soil has a threshold limit for holding phosphate, and any excess amount may be transported through surface runoff or contaminate groundwater through leachate, potentially affecting aquatic ecosystems and water quality. This study explores the efficiency of electrocoagulation and electrooxidation methods in treating egg-wash wastewater. These methods aim to remove pollutants and reduce their environmental impact. [Display omitted] • Egg-wash wastewater contains a higher concentration of pollutants • High COD, TDN, and phosphate increases the environmental concern • Operational parameters were optimized to achieve better pollutant removal • Pollutant reduction could be effective for the resource recovery of contaminates [ABSTRACT FROM AUTHOR]

Abstract The nano forms of the metals molybdenum oxide (MoO 3), nickel oxide (NiO) and lithium oxide (Li 2 O) are finding wide application in advanced technologies including batteries and fuel cells. We evaluated soil responses to nanoMoO 3 , nanoNiO, and nanoLi 2 O as some environmental release of the materials, either directly or following the land application of biosolids, is expected. Using Drummer soil (Fine-silty, mixed, superactive, mesic Typic Endoaquolls), we evaluated the impacts of the three nanometals on soil gas (N 2 O, CH 4 , and CO 2) emissions, enzyme activities (β-glucosidase and urease), and microbial community structure (bacterial, archaeal, and eukaryal) in a 60 day microcosms incubation. Soil treated with nanoLi 2 O at 474 μg Li/g soil, released 3.45 times more CO 2 with respect to the control. Additionally, β-glucosidase activity was decreased while urease activity increased following nanoLi 2 O treatment. While no clear patterns were observed for gas emissions in soils exposed to nanoMoO 3 and nanoNiO, we observed a temporary suppression of β-glucosidase activity in soil treated with either metal. All three domains of microbial community were affected by increasing metal concentrations. This is the first evaluation of soil responses to nanoMoO 3 , nanoNiO, or nanoLi 2 O. Graphical abstract Unlabelled Image Highlights • Soil treated with nanoLi 2 O released 3.45 times more CO 2 than untreated soil. • Further, nanoLi 2 O decreased soil β-glucosidase while increased urease activity. • nanoMoO 3 and nanoNiO produce temporary suppression of soil β-glucosidase. • Microbial community structures were affected by molybdenum-, nickel-, and lithium- oxide nanomaterials. [ABSTRACT FROM AUTHOR]

It has been predicted that the precipitation and atmospheric nitrogen (N) deposition will increase in northern China. Though a variety of publications have documented the effects of increased precipitation and N deposition on aboveground plant community, the responses of soil microbial community composition and function to these possible global changes still remain largely unknown. In this study, we take advantage of a long-term (9-year) field experiment that was established in a typical steppe in Inner Mongolia, China. The responses of microbial community composition and soil enzymatic activities to simulated N deposition and increased precipitation were examined. It was found that the low level of N addition showed no influence on the relative abundance of bacteria, but the relatively high N deposition increased the relative abundance of bacteria. The increased precipitation in combination with N addition, estimated at all N levels, significantly decreased the relative abundance of fungi and fungi/bacteria ratio. Increased precipitation played important roles in enhancing microbial activity in this semi-arid region. It was observed that water supply increased the activities of the five of the enzymes determined, including peroxidase (PER), polyphenol oxidase (PPO), β-Glucosidase (BG), protease (PRO) and alkaline phosphomonoesterase (alkaline PME). The activity of cellulase was reduced by long-term increased precipitation treatment, but was stimulated by simulated N deposition, which may due to the changes in litter components under projected climate change. The influences of N deposition on the microbial enzymatic activities might be alleviated (such as PER), strengthened (acid PME), or not affected by the projected precipitation increment. We also found that the overall changes in soil enzymatic activity patterns are more sensitive to environmental changes than the variations in soil microbial community composition, which may be explained by the microbial function redundancy and the limitations of research method. By all accounts, in future scenarios of increased precipitation in combination with N deposition, the proportion of soil fungi would be reduced, and the microbial community composition might be shifted to be bacteria-dominant. We also predicted that with the increasing of N deposition level, the activities of cellulolase would be enhanced, whereas the activities of ligninolytic enzymes (PER and PPO) would be reduced sharply. [ABSTRACT FROM AUTHOR]

Currently we lack knowledge on how the soil microbial community responds to the transition from traditional grain production to cellulosic feedstock production systems with residue removal for biofuel production. Implementation of second-generation biofuel production systems could create a challenge in meeting the goal of providing cellulose biomass if the processes impact soil's function as part of ecosystem services. Our goal was to assess the transition period as we move from a grain harvest system with residue return into biomass production systems with both residue and grain removal. The existing traditional systems were continuous corn (CC) and corn–soybean rotations (corn–soybean–corn (R1) or soybean–corn–soybean (R2)). The biomass production systems include a previously established mixed tall grass prairie dominated by big bluestem ( Andropogon gerardii ; PR) where the above ground biomass is now harvested when it had been previously burned, corn–soybean rotations transitioned to residue recovery based on: Miscanthus × giganteus (MS), dual-purpose sorghum ( Sorghum bicolor ; SG), upland switchgrass ( Panicum virgatum ; c.v. Shawnee ; SW) and a tilled continuous corn changed to continuous no-till corn ( Zea mays ; CR) with the residue removed. Over a three-year transition period, biological indicators of soil health included microbial biomass and community structure profile using phospholipid fatty acid (PLFA) biochemical markers, and an assessment of the saprotrophic fungal diversity using denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction amplified ITS rRNA genetic marker. Over the course of the transition, bacterial biomass dominated soils in the annual systems of CC, R1, R2, CR and SG, and the perennial system of MS. While fungal biomass dominated soils under PR. Fungal PLFA signatures and ITS-DGGE profiles demonstrated similarity between PR and the transitioned SW system, and to a lesser extent SG. In contrast, MS did not statistically alter the microbial biomass, community structure or fungal diversity away from patterns observed in the corn–soybean system. Our findings support microbial community stability and resilience as we found no negative impacts in any of the biomass recovery systems (PR, MS, SG, SW and CR) relative to the traditional systems (CC, R1 and R2), as indicated by measures of soil health. We did find that the selection of the plant types used in the biomass system could have a significant impact on the structure of both bacterial and fungal communities. With respect to soil health indicators including the fungal community, our findings suggest the dual-purpose SG system provides an encouraging alternative to continuous maize when considering plant biomass production. The selection of this dedicated perennial biomass system offers an avenue to enhance indicators of soil health and associated ecosystem services while supporting the bioenergy economy. [ABSTRACT FROM AUTHOR]

Soil microorganisms secrete enzymes used to metabolize carbon (C), nitrogen (N), and phosphorus (P) from the organic materials typically found in soil. Because of the connection with the active microbial biomass, soil enzyme activities can be used to investigate microbial nutrient cycling including the microbial response to environmental changes, transformation rates and to address the location of the most active biomass. In a 9-year field study on global change scenarios related to increasing N inputs (ambient to 15 g N m−2 yr−1) and precipitation (ambient to 180 mm yr−1), we tested the activities of soil β-glucosidase (BG), N-acetyl-glucosaminidase (NAG) and acid phosphomonoesterase (PME) for three soil aggregate classes: large macroaggregates (>2000 μm), small macroaggregates (250-2000 μm) and microaggregates (<250 μm). Results showed higher BG and PME activities in micro-vs. small macroaggregates whereas the highest NAG activity was found in the large macroaggregates. This distribution of enzyme activity suggests a higher contribution of fast-growing microorganisms in the micro-compared with the macroaggregates size fractions. The responses of BG and PME were different from NAG activity under N addition, as BG and PME decreased as much as 47.1% and 36.3%, respectively, while the NAG increased by as much as 80.8%, which could imply better adaption of fungi than bacteria to lower soil pH conditions developed under increased N. Significant increases in BG and PME activities by as much as 103.4 and 75.4%, respectively, were found under water addition. Lower ratio of BG:NAG and higher NAG:PME underlined enhanced microbial N limitation relative to both C and P, suggesting the repression of microbial activity and the accompanied decline in their ability to compete for N with plants and/or the accelerated proliferation of soil fungi under elevated N inputs. We conclude that changes in microbial activities under increased N input and greater water availability in arid- and semi-arid grassland ecosystems where NPP is co-limited by N and water may result in substantial redistribution of microbial activity in different-sized soil particles. This shift will influence the stability of SOM in the soil aggregates and the nutrient limitation of soil biota. [ABSTRACT FROM AUTHOR]