Biodegradation of toluene vapor in coir based upflow packed bed reactor by <Emphasis Type="Italic">Trichoderma asperellum</Emphasis> isolate

In the present study, a new biofiltration system involving a selective microbial strain isolated from aerated municipal sewage water attached with coir as packing material was developed for toluene degradation. The selected fungal isolate was identified as Trichoderma asperellum by 16S ribosomal RNA (16S rRNA) sequencing method, and pylogenetic tree was constructed using BLASTn search. Effect of various factors on growth and toluene degradation by newly isolated T. asperellum was studied in batch studies, and the optimum conditions were found to be pH 7.0, temperature 30 °C, and initial toluene concentration 1.5 (v/v)%. Continuous removal of gaseous toluene was monitored in upflow packed bed reactor (UFPBR) using T. asperellum. Effect of various parameters like column height, flow rate, and the inlet toluene concentration were studied to evaluate the performance of the biofilter. The maximum elimination capacity (257 g m^?3 h^?1) was obtained with the packing height of 100 cm with the empty bed residence time of 5 min. Under these optimum conditions, the T. asperellum showed better toluene removal efficiency. Kinetic models have been developed for toluene degradation by T. asperellum using macrokinetic approach of the plug flow model incorporated with Monod model.     

Fumaric acid production using renewable resources from biodiesel and cane sugar production processes

The microbial production of fumaric acid by Rhizopus arrhizus NRRL 2582 has been evaluated using soybean cake from biodiesel production processes and very high polarity (VHP) sugar from sugarcane mills. Soybean cake was converted into a nutrient-rich hydrolysate via a two-stage bioprocess involving crude enzyme production via solid state fermentations (SSF) of either Aspergillus oryzae or R. arrhizus cultivated on soybean cake followed by enzymatic hydrolysis of soybean cake. The soybean cake hydrolysate produced using crude enzymes derived via SSF of R. arrhizus was supplemented with VHP sugar and evaluated using different initial free amino nitrogen (FAN) concentrations (100, 200, and 400 mg/L) in fed-batch cultures for fumaric acid production. The highest fumaric acid concentration (27.3 g/L) and yield (0.7 g/g of total consumed sugars) were achieved when the initial FAN concentration was 200 mg/L. The combination of VHP sugar with soybean cake hydrolysate derived from crude enzymes produced by SSF of A. oryzae at 200 mg/L initial FAN concentration led to the production of 40 g/L fumaric acid with a yield of 0.86 g/g of total consumed sugars. The utilization of sugarcane molasses led to low fumaric acid production by R. arrhizus, probably due to the presence of various minerals and phenolic compounds. The promising results achieved through the valorization of VHP sugar and soybean cake suggest that a focused study on molasses pretreatment could lead to enhanced fumaric acid production.     

Phycoremediation potential of marine microalga <Emphasis Type="Italic">Tetraselmis indica</Emphasis> on secondary treated domestic sewage for nutrient removal and biodiesel production

Marine microalga Tetraselmis indica (T. indica) was cultivated in secondary treated domestic sewage (STDS) in batch mode. Optimization studies showed that after 14 days of cultivation period, highest biomass yield reached was 0.88 ± 0.04 g/L at the optimum temperature of 27 ± 1 °C and light intensity of 135 μmol m^?2 s^?1. T. indica removed about 60.93% phosphate, 78.46% nitrate, 72.94% chemical oxygen demand (COD), 73.17% biological oxygen demand (BOD), 98.90% total dissolved solids (TDS) and heavy metals (83.11% Cd, 55.67% Ca, 45.12% Cu, 13.67% Mn, 50.88% Pb, and 98.92% Al) from STDS. The level of electrical conductivity was reduced to 0.0974 ± 0.045 dS/m. The fatty acid methyl ester (FAME) profile showed the presence of palmitic acid (12.91%), oleic acid (35.94%), linoleic acid (14.89%) and eicosanoic acid (12.34%). This study indicates the potential of T. indica for removal of pollutants from STDS and also its capability of biodiesel production.     

Study on preparation method of <Emphasis Type="Italic">Zanthoxylum bungeanum</Emphasis> seeds kernel oil with zero trans-fatty acids

The seed of Zanthoxylum bungeanum (Z. bungeanum) is a by-product of pepper production and rich in unsaturated fatty acid, cellulose, and protein. The seed oil obtained from traditional producing process by squeezing or extracting would be bad quality and could not be used as edible oil. In this paper, a new preparation method of Z. bungeanum seed kernel oil (ZSKO) was developed by comparing the advantages and disadvantages of alkali saponification-cold squeezing, alkali saponification-solvent extraction, and alkali saponification-supercritical fluid extraction with carbon dioxide (SFE-CO₂). The results showed that the alkali saponification-cold squeezing could be the optimal preparation method of ZSKO, which contained the following steps: Z. bungeanum seed was pretreated by alkali saponification under the conditions of adding 10 %NaOH (w/w), solution temperature was 80 °C, and saponification reaction time was 45 min, and pretreated seed was separated by filtering, water washing, and overnight drying at 50 °C, then repeated squeezing was taken until no oil generated at 60 °C with 15 % moisture content, and ZSKO was attained finally using centrifuge. The produced ZSKO contained more than 90 % unsaturated fatty acids and no trans-fatty acids and be testified as a good edible oil with low-value level of acid and peroxide. It was demonstrated that the alkali saponification-cold squeezing process could be scaled up and applied to industrialized production of ZSKO.     

Reusing colored industrial wastewaters in a photofermentation for enhancing biohydrogen production by using ultrasound stimulated <Emphasis Type="Italic">Rhodobacter sphaeroides</Emphasis>

One-time ultrasonication pre-treatment of Rhodobacter sphaeroides was evaluated for improving biohydrogen production via photofermentation. Batch experiments were performed by varying ultrasonication amplitude (15, 30, and 45%) and duration (5, 10, and 15 min) using combined effluents from palm oil as well as pulp and paper mill as a single substrate. Experimental data showed that ultrasonication at amplitude 30% for 10 min (256.33 J/mL) achieved the highest biohydrogen yield of 9.982 mL H₂/mL_medium with 5.125% of light efficiency. A maximum COD_total removal of 44.7% was also obtained. However, when higher ultrasonication energy inputs (>256.33 J/mL) were transmitted to the cells, biohydrogen production did not improve further. In fact, 20.6% decrease of biohydrogen yield (as compared to the highest biohydrogen yield) was observed using the most intense ultrasonicated inoculum (472.59 J/mL). Field emission scanning electron microscope images revealed the occurrence of cell damages and biomass losses if ultrasonication at 472.59 J/mL was used. The present results suggested that moderate ultrasonication pre-treatment was an effective technique to improve biohydrogen production performances of R. sphaeroides.     

Inhibition of residual <Emphasis Type="Italic">n</Emphasis>-hexane in anaerobic digestion of lipid-extracted microalgal wastes and microbial community shift

Converting lipid-extracted microalgal wastes to methane (CH₄) via anaerobic digestion (AD) has the potential to make microalgae-based biodiesel platform more sustainable. However, it is apparent that remaining n-hexane (C₆H₁₄) from lipid extraction could inhibit metabolic pathway of methanogens. To test an inhibitory influence of residual n-hexane, this study conducted a series of batch AD by mixing lipid-extracted Chlorella vulgaris with a wide range of n-hexane concentration (～10 g chemical oxygen demand (COD)/L). Experimental results show that the inhibition of n-hexane on CH₄ yield was negligible up to 2 g COD/L and inhibition to methanogenesis became significant when it was higher than 4 g COD/L based on quantitative mass balance. Inhibition threshold was about 4 g COD/L of n-hexane. Analytical result of microbial community profile revealed that dominance of alkane-degrading sulfate-reducing bacteria (SRB) and syntrophic bacteria increased, while that of methanogens sharply dropped as n-hexane concentration increased. These findings offer a useful guideline of threshold n-hexane concentration and microbial community shift for the AD of lipid-extracted microalgal wastes.     

A study on production of biodiesel using a novel solid oxide catalyst derived from waste

The issues of energy security, dwindling supply and inflating price of fossil fuel have shifted the global focus towards fuel of renewable origin. Biodiesel, having renewable origin, has exhibited great potential as substitute for fossil fuels. The most common route of biodiesel production is through transesterification of vegetable oil in presence of homogeneous acid or base or solid oxide catalyst. But, the economics of biodiesel is not competitive with respect to fossil fuel due to high cost of production. The vegetable oil waste is a potential alternative for biodiesel production, particularly when disposal of used vegetable oil has been restricted in several countries. The present study evaluates the efficacy of a low-cost solid oxide catalyst derived from eggshell (a food waste) in transesterification of vegetable oil and simulated waste vegetable oil (SWVO). The impact of thermal treatment of vegetable oil (to simulate frying operation) on transesterification using eggshell-derived solid oxide catalyst (ESSO catalyst) was also evaluated along with the effect of varying reaction parameters. The study reported that around 90 % biodiesel yield was obtained with vegetable oil at methanol/oil molar ratio of 18:1 in 3 h reaction time using 10 % ESSO catalyst. The biodiesel produced with ESSO catalyst from SWVO, thermally treated at 150 °C for 24 h, was found to conform with the biodiesel standard, but the yield was 5 % lower compared to that of the untreated oil. The utilization of waste vegetable oil along with waste eggshell as catalyst is significant for improving the overall economics of the biodiesel in the current market. The utilization of waste for societal benefit with the essence of sustainable development is the novelty of this work.     

Pilot project at Hazira,India, for capture of carbon dioxide and its biofixation using microalgae

The objective of the present study was to set up a small-scale pilot reactor at ONGC Hazira, Surat, for capturing CO₂ from vent gas. The studies were carried out for CO₂ capture by either using microalgae Chlorella sp. or a consortium of microalgae (Scenedesmus quadricauda, Chlorella vulgaris and Chlorococcum humicola). The biomass harvested was used for anaerobic digestion to produce biogas. The carbonation column was able to decrease the average 34 vol.% of CO₂ in vent gas to 15 vol.% of CO₂ in the outlet gas of the carbonation column. The yield of Chlorella sp. was found to be 18 g/m²/day. The methane yield was 386 l CH₄/kg VS_fed of Chlorella sp. whereas 228 l CH₄/kg VS_fed of the consortium of algae.     

Mixotrophic cultivation of microalgae using industrial flue gases for biodiesel production

In the present study, an attempt has been made to grow microalgae Scenedesmus quadricauda, Chlorella vulgaris and Botryococcus braunii in mixotropic cultivation mode using two different substrates, i.e. sewage and glucose as organic carbon sources along with flue gas inputs as inorganic carbon source. The experiments were carried out in 500 ml flasks with sewage and glucose-enriched media along with flue gas inputs. The composition of the flue gas was 7 % CO₂, 210 ppm of NO _x and 120 ppm of SO _x . The results showed that S. quadricauda grown in glucose-enriched medium yielded higher biomass, lipid and fatty acid methyl esters (FAME) (biodiesel) yields of 2.6, 0.63 and 0.3 g/L, respectively. Whereas with sewage, the biomass, lipid and FAME yields of S. quadricauda were 1.9, 0.46, and 0.21 g/L, respectively. The other two species showed closer results as well. The glucose utilization was measured in terms of Chemical Oxygen Demand (COD) reduction, which was up to 93.75 % by S. quadricauda in the glucose-flue gas medium. In the sewage-flue gas medium, the COD removal was achieved up to 92 % by S. quadricauda. The other nutrients and pollutants from the sewage were removed up to 75 % on an average by the same. Concerning the flue gas treatment studies, S. quadricauda could remove CO₂ up to 85 % from the flue gas when grown in glucose medium and 81 % when grown in sewage. The SO _x and NO _x concentrations were reduced up to 50 and 62 %, respectively, by S. quadricauda in glucose-flue gas medium. Whereas, in the sewage-flue gas medium, the SO _x and NO _x concentrations were reduced up to 45 and 50 %, respectively, by the same. The other two species were equally efficient however with little less significant yields and removal percentages. This study laid emphasis on comparing the feasibility in utilization of readily available carbon sources like glucose and inexpensive leftover carbon sources like sewage by microalgae to generate energy coupled with economical remediation of waste. Therefore on an industrial scale, the sewage is more preferable. Because the results obtained in the laboratory demonstrated both sewage and glucose-enriched nutrient medium are equally efficient for algae cultivation with just a slight difference. Essentially, the sewage is cost effective and easily available in large quantities compared to glucose.     

Copper bioaccumulation,photosystem II functioning,and oxidative stress in the seagrass <Emphasis Type="Italic">Cymodocea nodosa</Emphasis> exposed to copper oxide nanoparticles

Photosynthetic activity, oxidative stress, and Cu bioaccumulation in the seagrass Cymodocea nodosa were assessed 4, 12, 24, 48, and 72 h after exposure to two copper oxide nanoparticle (CuO NP) concentrations (5 and 10 mg L^?1). CuO NPs were characterized by scanning electron microscopy (SEM) and dynamic light scattering measurements (DLS). Chlorophyll fluorescence analysis was applied to detect photosystem II (PSII) functionality, while the Cu accumulation kinetics into the leaf blades was fitted to the Michaelis-Menten equation. The uptake kinetics was rapid during the first 4 h of exposure and reached an equilibrium state after 10 h exposure to 10 mg L^?1 and after 27 h to 5 mg L^?1 CuO NPs. As a result, 4-h treatment with 5 mg L^?1 CuO NPs, decreased the quantum yield of PS II photochemistry (Φ _PSΙΙ ) with a parallel increase in the regulated non-photochemical energy loss in PSII (Φ _NPQ ). However, the photoprotective dissipation of excess absorbed light energy as heat, through the process of non-photochemical quenching (NPQ), did not maintain the same fraction of open reaction centers (q _p ) as in control plants. This reduced number of open reaction centers resulted in a significant increase of H₂O₂ production in the leaf veins serving possibly as an antioxidant defense signal. Twenty-four-hour treatment had no significant effect on Φ _PSΙΙ and q _p compared to controls. However, 24 h exposure to 5 mg L^?1 CuO NPs increased the quantum yield of non-regulated energy loss in PSII (Φ _NO ), and thus the formation of singlet oxygen (¹O₂) via the triplet state of chlorophyll, possible because the uptake kinetics had not yet reached the equilibrium state as did 10 mg L^?1. Longer-duration treatment (48 and 72 h) had less effect on the allocation of absorbed light energy at PSII and the fraction of open reaction centers, compared to 4-h treatment, suggesting the function of a stress defense mechanism. The response of C. nodosa leaves to CuO NPs fits the “Threshold for Tolerance Model” with a threshold time (more than 4 h) required for induction of a stress defense mechanism, through H₂O₂ production.     

Harnessing dark fermentative hydrogen from pretreated mixture of food waste and sewage sludge under sequencing batch mode

Food waste and sewage sludge are the most abundant and problematic organic wastes in any society. Mixture of these two wastes may provide appropriate substrate condition for dark fermentative biohydrogen production based on synergistic mutual benefits. This work evaluates continuous hydrogen production from the cosubstrate of food waste and sewage sludge to verify mechanisms of performance improvement in anaerobic sequencing batch reactors. Volatile solid concentration and mixing ratio of food waste and sludge were adjusted to 5 % and 80:20, respectively. Five different hydraulic retention times (HRT) of 36, 42, 48, 72, and 108 h were tested using anaerobic sequencing batch reactors to find out optimal operating condition. Results show that the best performance was achieved at HRT 72 h, where the hydrogen yield, the hydrogen production rate, and hydrogen content were 62.0 mL H₂/g VS, 1.0 L H₂/L/day, and ~50 %, respectively. Sufficient solid retention time (143 h) and proper loading rate (8.2 g COD/L/day as carbohydrate) at HRT 72h led to the enhanced performance with better hydrogen production showing appropriate n-butyrate/acetate (B/A) ratio of 2.6. Analytical result of terminal-restriction fragment length polymorphism revealed that specific peaks associated with Clostridium sp. and Bacillus sp. were strongly related to enhanced hydrogen production from the cosubstrate of food waste and sewage sludge.     

<Emphasis Type="Italic">Ailanthus Altissima</Emphasis> and <Emphasis Type="Italic">Phragmites Australis</Emphasis> for chromium removal from a contaminated soil

The comparative effectiveness for hexavalent chromium removal from irrigation water, using two selected plant species (Phragmites australis and Ailanthus altissima) planted in soil contaminated with hexavalent chromium, has been studied in the present work. Total chromium removal from water was ranging from 55 % (Phragmites) to 61 % (Ailanthus). After 360 days, the contaminated soil dropped from 70 (initial) to 36 and 41 mg Cr/kg (dry soil), for Phragmites and Ailanthus, respectively. Phragmites accumulated the highest amount of chromium in the roots (1910 mg Cr/kg_{(dry tissue)}), compared with 358 mg Cr/kg_{(dry tissue)} for Ailanthus roots. Most of chromium was found in trivalent form in all plant tissues. Ailanthus had the lowest affinity for Cr^VI reduction in the root tissues. Phragmites indicated the highest chromium translocation potential, from roots to stems. Both plant species showed good potentialities to be used in phytoremediation installations for chromium removal.     

Tolerance of Japanese knotweed <Emphasis Type="Italic">s</Emphasis>.<Emphasis Type="Italic">l</Emphasis>. to soil artificial polymetallic pollution: early metabolic responses and performance during vegetative multiplication

The expansion of invasive Japanese knotweed s.l. is of particular concern because of its aptitudes to rapidly colonize diverse environments, especially anthropized habitats generally characterized by their pollution with heavy metals. Whether the presence of heavy metals impacts the performance traits of this plant is a central question to better understand its invasive properties, though no controlled approach to assess these effects was yet reported. In this aim, we undertook greenhouse experiments where rhizome fragments of Japanese knotweed s.l. (Fallopia japonica and Fallopia × bohemica) were grown during 1 and 3 months, in a soil pot artificially polluted or not with heavy metals added in mixture (Cd, Cr, Pb, Zn). Our results showed that (i) the presence of heavy metals delayed rhizome regeneration and induced lowered plant part weights but did not affect plant height after 3 months; (ii) the effect of metals on the metabolic profiles of belowground part extracts was only detectable after 1 month and not after 3 months of growth, though it was possible to highlight the effect of metals independently of time and genotype for root extracts, and torosachrysone seemed to be the most induced compound; and (iii) the hybrid genotype tested was able to accumulate relatively high concentrations of metals, over or close to the highest reported ones for this plant for Cr, Cd and Zn, whereas Pb was not accumulated. These findings evidence that the presence of heavy metals in soil has a low impact on Fallopia sp. overall performance traits during rhizome regeneration, and has a rather stimulating effect on plant growth depending on pollution level.     

Nitrogen and plant population change radiation capture and utilization capacity of sunflower in semi-arid environment

The combination of nitrogen and plant population expresses the spatial distribution of crop plants. The spatial distribution influences canopy structure and development, radiation capture, accumulated intercepted radiation (Sa), radiation use efficiency (RUE), and subsequently dry matter production. We hypothesized that the sunflower crop at higher plant populations and nitrogen (N) rates would achieve early canopy cover, capture more radiant energy, utilize radiation energy more efficiently, and ultimately increase economic yield. To investigate the above hypothesis, we examined the influences of leaf area index (LAI) at different plant populations (83,333, 66,666, and 55,555 plants ha^?1) and N rates (90, 120, and 150 kg ha^?1) on radiation interception (Fi), photosynthetically active radiation (PAR) accumulation (Sa), total dry matter (TDM), achene yield (AY), and RUE of sunflower. The experimental work was conducted during 2012 and 2013 on sandy loam soil in Punjab, Pakistan. The sunflower crop captured more than 96% of incident radiant energy (mean of all treatments), 98% with a higher plant population (83,333 plants ha^?1), and 97% with higher N application (150 kg ha^?1) at the fifth harvest (60 days after sowing) during both study years. The plant population of 83,333 plants ha^?1 with 150 kg N ha^?1 ominously promoted crop, RUE, and finally productivity of sunflower (AY and TDM). Sunflower canopy (LAI) showed a very close and strong association with Fi (R ² = 0.99 in both years), PAR (R ² = 0.74 and 0.79 in 2012 and 2013, respectively), TDM (R ² = 0.97 in 2012 and 0.91 in 2013), AY (R ² = 0.95 in both years), RUE for TDM (RUE_TDM) (R ² = 0.63 and 0.71 in 2012 and 2013, respectively), and RUE for AY (RUE_AY) (R ² = 0.88 and 0.87 in 2012 and 2013, respectively). Similarly, AY (R ² = 0.73 in 2012 and 0.79 in 2013) and TDM (R ² = 0.75 in 2012 and 0.84 in 2013) indicated significant dependence on PAR accumulation of sunflower. High temperature during the flowering stage in 2013 shortened the crop maturity duration, which reduced the LAI, leaf area duration (LAD), crop growth rate (CGR), TDM, AY, Fi, Sa, and RUE of sunflower. Our results clearly revealed that RUE was enhanced as plant population and N application rates were increased and biomass assimilation in semi-arid environments varied with radiation capture capacity of sunflower.     

Haze is a risk factor contributing to the rapid spread of respiratory syncytial virus in children

This study investigated whether respiratory syncytial virus (RSV) infection in children was associated with ambient temperature and air pollutants in Hangzhou, China. A distributed lag non-linear model (DLNM) was used to estimate the effects of daily meteorological data and air pollutants on the incidence of RSV infection among children. A total of 3650 childhood RSV infection cases were included in the study. The highest air pollutant concentrations were in January to May and October to December during the year. The yearly RSV-positive rate was 10.0 % among children with an average age of 4.3 months. The highest RSV-positive rate occurred among patients 0 to 3 months old. Children under 6.5 months old accounted for 80 % of the total patients infected by RSV. A negative correlation was found between ambient temperature and RSV infection, and it was strongest with minimum ambient temperature (r = ?0.804, P < 0.001). There was a positive correlation between the infection rate and the particulate matter (PM) 2.5 (r = 0.446, P < 0.001), PM10 (r = 0.397, P < 0.001), SO₂ (r = 0.389, P < 0.001), NO₂ (r = 0.365, P < 0.001) and CO (r = 0.532, P < 0.001). The current study suggested that temperature was an important factor associated with RSV infection among children in Hangzhou. Air pollutants significantly increased the risk of RSV infection with dosage, lag and cumulative effects.     

Toxicity evaluation of cypermethrin,glyphosate, and malathion,on two indigenous zooplanktonic species

In Aguascalientes, Mexico, there is a special concern about pesticides because of their intensive use on guava production areas, which are located in the vicinity of water reservoirs; thus, non-target organisms could be exposed. Thereafter, the aim of this work was to assess the effect of cypermethrin, Faena® (glyphosate), and malathion, which are the most used pesticides in Aguascalientes’ guava production, on the indigenous freshwater species Alona guttata (cladoceran) and Lecane papuana (rotifer). Acute 48-h toxicity tests were carried out, and LC₅₀ values were calculated. Then, five sublethal concentrations (1/80, 1/40, 1/20, 1/10, and 1/5 of the respective LC₅₀) were selected for the chronic assays: (a) intrinsic growth rate analysis in the rotifer and (b) partial life table analysis in the cladoceran. The results of the acute toxicity tests showed that A. guttata was more sensitive to malathion (LC₅₀ = 5.26 × 10^?3 mg/L) at concentrations found in natural environments with continuous application on guava fields, whereas L. papuana was more sensitive to Faena® (LC₅₀ = 19.89 mg/L). The somatic growth of A. guttata was inhibited for the chronic exposure to cypermethrin. In addition, cypermethrin and Faena® seemed to exert endocrine disruptive effects on A. guttata. Moreover, malathion chronic exposure significantly decreased the survival of A. guttata. Moreover, L. papuana was affected chronically for the three pesticides.     

Isolation and characterization of two novel psychrotrophic decabromodiphenyl ether-degrading bacteria from river sediments

Decabromodiphenyl ether (BDE-209) is a brominated flame retardant and a priority contaminant. Currently, little information is available about its significance in the environment, specifically about its susceptibility to aerobic biotransformation at low temperature. In this work, five phylogenetically diverse BDE-209-degrading bacterial strains were isolated from river sediments of northern China. These strains were distributed among four different genera—Acinetobacter, Pseudomonas, Bacillus and Staphylococcus. All five isolates were capable of growing on BDE-209, among which two isolates show better growth. By detailed morphological, physiological, and biochemical characteristics and 16S rDNA sequence analysis, the two strains were identified and named as Staphylococcus haemolyticus LY1 and Bacillus pumilus LY2. The two bacteria can grow in mineral salt medium containing BDE-209 substrate across the temperatures ranging from 2.5 to 35 °C, with an optimum temperature of 25 °C which could be considered as psychrotrophs accordingly. The degradation experiment showed that more than 70.6 and 85.5 % of 0.5 mg/L BDE-209 were degraded and the highest mineralization efficiencies of 29.8 and 39.2 % were achieved for 0.5 mg/L BDE-209 by S. haemolyticus LY1 and B. pumilus LY2, respectively. To the best of our knowledge, this is the first demonstration for the biodegradation of BDE-209 by two psychrotrophic bacteria isolated from environment.     

Matrix effect in case of purification of oily waters by membrane separation combined with pre-ozonation

In the present study, oil in water emulsions (c_oil?=?100 ppm; d_{oil droplets}?<?2 μm) was purified with ozonation followed by microfiltration using polyethersulfone (PES) membrane (d_pore?=?0.2 μm). The effects of pre-ozonation on membrane microfiltration were investigated in detail both in case of ultrapure and model groundwater matrices, applying different durations (0, 5, 10, and 20 min) of pre-ozonation. Simultaneously, the effects of added inorganic water components on the combined method were investigated. Size distribution of oil droplets, zeta potentials, fluxes, and purification efficiencies were measured and fouling mechanisms were described in all cases. It was found that the matrix significantly affected the size distribution and adherence ability of oil droplets onto the membrane surface, therefore fouling mechanisms also were strongly dependent on the matrix. In case of low salt concentration, the total resistance was caused mainly by reversible resistance, which could be significantly reduced (eliminated) by pre-ozonation. In case of model groundwater matrix, nearly twice higher total resistance was measured, and irreversible resistance was dominant, because of the higher adhesion ability of the oil droplets onto the membrane surface. In this case, pre-ozonation resulted in much lower irreversible, but higher reversible resistance. Increased duration of pre-ozonation raised the total resistance and reduced the elimination efficiency (due to fragmented oil droplets and water soluble oxidation by-products) in both cases, therefore short pre-ozonation can be recommended both from economic and performance aspects.     

Removal ratio of gaseous toluene and xylene transported from air to root zone via the stem by indoor plants

This work was designed to investigate the removal efficiency as well as the ratios of toluene and xylene transported from air to root zone via the stem and by direct diffusion from the air into the medium. Indoor plants (Schefflera actinophylla and Ficus benghalensis) were placed in a sealed test chamber. Shoot or root zone were sealed with a Teflon bag, and gaseous toluene and xylene were exposed. Removal efficiency of toluene and total xylene (m, p, o) was 13.3 and 7.0 μg·m^?3·m^?2 leaf area over a 24-h period in S. actinophylla, and was 13.0 and 7.3 μg·m^?3·m^?2 leaf area in F. benghalensis. Gaseous toluene and xylene in a chamber were absorbed through leaf and transported via the stem, and finally reached to root zone, and also transported by direct diffusion from the air into the medium. Toluene and xylene transported via the stem was decreased with time after exposure. Xylene transported via the stem was higher than that by direct diffusion from the air into the medium over a 24-h period. The ratios of toluene transported via the stem versus direct diffusion from the air into the medium were 46.3 and 53.7 % in S. actinophylla, and 46.9 and 53.1 % in F. benghalensis, for an average of 47 and 53 % for both species. The ratios of m,p-xylene transported over 3 to 9 h via the stem versus direct diffusion from the air into the medium was 58.5 and 41.5 % in S. actinophylla, and 60.7 and 39.3 % in F. benghalensis, for an average of 60 and 40 % for both species, whereas the ratios of o-xylene transported via the stem versus direct diffusion from the air into the medium were 61 and 39 %. Both S. actinophylla and F. benghalensis removed toluene and xylene from the air. The ratios of toluene and xylene transported from air to root zone via the stem were 47 and 60 %, respectively. This result suggests that root zone is a significant contributor to gaseous toluene and xylene removal, and transported via the stem plays an important role in this process.     

Accumulation of Cr,Cd, Pb,Cu, and Zn by plants in tanning sludge storage sites: opportunities for contamination bioindication and phytoremediation

Tanning sludge enriched with high concentrations of Cr and other metals has adverse effects on the environment. Plants growing in the metalliferous soils may have the ability to cope with high metal concentrations. This study focuses on potentials of using native plants for bioindication and/or phytoremediation of Cr-contaminated sites. In the study, we characterized plants and soils from six tanning sludge storage sites. Soil in these sites exhibited toxic levels of Cr (averaged 16,492 mg kg^?1) and other metals (e.g., 48.3 mg Cu kg^?1, 2370 mg Zn kg^?1, 44.9 mg Pb kg^?1, and 0.59 mg Cd kg^?1). Different metal tolerance and accumulation patterns were observed among the sampled plant species. Phragmites australis, Zephyranthes candida, Cynodon dactylon, and Alternanthera philoxeroides accumulated moderate-high concentrations of Cr and other metals, which could make them good bioindicators of heavy metal pollution. High Cr and other metal concentrations (e.g., Cd and Pb) were found in Chenopodium rubrum (372 mg Cr kg^?1), Aster subulatus (310 mg Cr kg^?1), and Brassica chinensis (300 mg Cr kg^?1), being considered as metal accumulators. In addition, Nerium indicum and Z. candida were able to tolerate high concentrations of Cr and other metals, and they may be used as preferable pioneer species to grow or use for restoration in Cr-contaminated sites. This study can be useful for establishing guidelines to select the most suitable plant species to revegetate and remediate metals in tanning sludge-contaminated fields.