Sustainable removal of pernicious arsenic and cadmium by a novel composite of MnO2 impregnated alginate beads: A cost-effective approach for wastewater treatment.

There is a dire necessity of developing low cost waste water treatment systems, for the efficient removal of noxious heavy metals (and metalloids) such as Arsenic (As) and Cadmium (Cd). Magnetic biopolymer (CABs-MO) was synthesized by the entrapment of nanocrystalline MnO2 in the polymeric microcapsules of calcium alginate (CABs). Batch experiments were conducted under constant pH (6.5), temperature (25OC), different initial concentrations (30-300 mg L-1) and contact times (0-48 h) to study the adsorption isotherms and removal kinetics of pristine (CABs) and hybrid biopolymer (CABs-MO) for the removal of As and Cd. The pseudo-equilibrium process was mathematically well explained by the pseudo-second-order kinetic (R2 ≥ 0.99) and Langmuir isotherm model (R2 ≥ 0.99) with the highest monolayer sorption capacity of 63.6 mg g-1 for Cd on CABs-MO. The As removal rate was maximum up to 6.5 mg g-1 after 12 h of contact period in a single contaminant system than in the mixed contaminant (As + Cd) system (0.8 mg g-1), though the effect was non-significant for Cd (p < 0.05; t-test). The performance of the 10 mM HCl as a regenerating agent was superior (for As in comparison to Cd, p < 0.05; t-test) compared to distilled water (DW) through three to five regeneration cycles. Therefore, the obtained results clearly validate the feasibility of CABs-MO as a potential promising adsorbent for removing metal contaminants from the wastewater. Further research is required to study the decontamination of emerging contaminants with such novel composite beads characterized by varied physico-chemical properties.

Efficacy and field applicability of Burmese grape leaf extract (BGLE) for cadmium removal: An implication of metal removal from natural water.

Burmese Grape Leaf Extract (BGLE), a low cost adsorbent was studied for cadmium (Cd(II)) removal from metal solutions and natural water samples. Batch adsorption studies were carried out to examine the influence of contact time and initial metal concentration after characterization under scanning electron microscopy (SEM). Cd(II)adsorptiononto BGLE was best explained by pseudo-second order kinetics (R2 = 0.99) and best fitted with Langmuir isotherm model (R2 = 0.76). Beside the selective adsorption activity of BGLE towards Cd(II), only 0.1g of BGLE have shown effective adsorption of these ions with a maximum adsorption capacity (qm) of 44.72mgg-1. This study was a unique combination of laboratory experiments and field implication. Study indicates that same efficacy cannot be obtained in natural water samples as obtained in the case of laboratory due to the interference of major ions in water.

Corn cob silica as an antibacterial support for silver nanoparticles: efficacy on Escherichia coli and Listeria monocytogenes.

There is great potential to combine bioresource and recycled materials with nanotechnology for industrial and environmental applications. In a novel approach, silver (Ag) nanoparticles (Ag NPs) were imbedded on amine-functionalized silica obtained from corn cob (ACCS) to produce a composite material that can be used to inactivate bacteria. Transmission electron microscope (TEM) images show near-uniform ACCS particles (34.7 ± 8.6 nm diameter), with Ag NPs (5-10 nm diameter) homogenously dispersed on the surfaces. The potential of ACCS-Ag NPs to rapidly inactivate gram-negative Escherichia coli ATCC 8739 and gram-positive Listeria monocytogenes was investigated. A four-log (> 99.99%) inactivation of the E. coli was achieved within 30 min with 4 mg of ACCS-Ag NPs in a 40-mL PBS suspension (1 × 105 CFU/mL). Extended exposure of ACCS-Ag NP may be required to inactivate L. monocytogenes, suggesting the ACCS-Ag NP composite will be less practical for gram-positive bacteria due to thick cell wall and alternative formulations may need to be developed. Result shows that the potential of corn cob silica as an alternative, eco-friendly support matrix for applications such as bacterial inactivation. The Ag-imbedded, amine-functionalized corn cob silica demonstrates how bio-waste can be combined with nanotechnology to produce useful materials.

Isolation of an exopolysaccharide-producing heavy metal-resistant Halomonas sp. MG.

An exopolysaccharide (EPS)-producing heavy metal-resistant Gram-negative bacterium was isolated from ore-contaminated soil. The selected strain was identified by 16S rDNA sequencing and designated as Halomonas sp. MG. Phylogenetic analysis of the gene sequence showed its close similarity with Halomonas sp. Field emission scanning electron microscopy analysis revealed that the EPS had a porous structure with small pores. X-ray diffractograms showed the non-crystalline nature of the EPS. Further, FTIR spectroscopic analysis revealed the presence of carboxyl, hydroxyl and amide groups corresponding to a typical EPS.

Isolation and Characterization of Multi-Metal-Resistant Halomonas sp. MG from Tamil Nadu Magnesite Ore Soil in India.

The aim of the study was to isolate and characterize potential multi-metal-resistant bacteria from ore soils. A total of three bacteria were isolated and assayed for resistance to arsenic (As), copper (Cu), and lead (Pb). Isolate Halomonas sp. MG exhibited maximum resistance to 1000 mg Pb/L, 800 mg As/L, and 500 mg Cu/L and it was identified as Halomonas sp. based on the partial 16S rDNA sequences. The metal(loid)s resistance mechanisms were further confirmed by amplification of arsC (As) copAU (Cu), and pbrT (Pb) genes. Biological transmission electron micrographs and XRD studies showed that the isolate Halomonas sp. MG transformed and/or biomineralized the metals either intracellularly or extracellularly. These results suggest that the isolate could be used as a potential candidate for the bioremediation of As, Cu, and Pb.

IAA production by Bacillus sp. JH 2-2 promotes Indian mustard growth in the presence of hexavalent chromium.

Bacillus sp. strain JH 2-2, isolated from the rhizosphere of plants at a multi-metal contaminated mine site, has the potential to reduce Cr(VI) to Cr(III) and promote plant growth by reducing Cr toxicity and producing IAA. The minimum inhibitory concentration of Cr(VI) to Bacillus sp. JH 2-2 was 1000 mg L(-1) and the strain reduced 99% of 10 mg Cr(VI) L(-1) to Cr(IV) within 24 h. Lower Cr(VI) stress (10 mg L(-1) ) stimulated IAA production, but much less IAA was produced at 30 or 50 mg Cr(VI) L(-1) . Inoculation with Bacillus sp. JH 2-2 increased the length of Brassica juncea L. roots by 364% and stems by 735% in the presence of 10 mg Cr(VI) L(-1) from those of uninoculated control plants. These findings suggest potential use of Bacillus sp. JH 2-2 to promote phytoremediation of soil contaminated with Cr(VI).

Trichoderma virens PDR-28: a heavy metal-tolerant and plant growth-promoting fungus for remediation and bioenergy crop production on mine tailing soil.

A heavy metal-tolerant fungus, Trichoderma virens PDR-28, was isolated from rhizosphere soil and evaluated for use in remediating mine tailing soil and for plant biomass production. PDR-28 exhibited plant growth-promoting traits, including 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, acid phosphatase and phytase activity, siderophore production, and P solubilization. HMs were more available in mine tailing soil inoculated soil with PDR-28 than in uninoculated soil; the order of HM bioleaching was Cd > As > Zn > Pb > Cu. PDR-28 effectively removed HMs in the order of Pb > Cd > As > Zn > Cu from liquid media containing 100 mg HM L(-1). Inoculating HM-contaminated mine tailing soil with the fungus significantly increased the dry biomass of maize roots (64%) and shoots (56%). Chlorophyll, total soluble sugars (reducible and nonreducible), starch, and protein contents increased by 46%, 28%, 30%, and 29%, respectively, compared to plants grown in uninoculated soil. Inoculation increased heavy metal concentrations in maize roots by 25% (Cu) to 62% (Cd) and in shoots by 35% (Cu) to 64% (Pb) compared to uninoculated plants. Results suggest that PDR-28 would be beneficial for phytostabilization and plant biomass production as a potential source of biofuel in the quest for renewable energy.

Pseudomonas fluorescens JH 70-4 promotes pb stabilization and early seedling growth of sudan grass in contaminated mining site soil.

A bacterial strain (JH 70-4) exhibiting plant growth promoting characteristics (indoleacetic acid production and 1-aminocyclopropane-1-carboxylate deaminase activity), as well as heavy metal(loid) (HM) tolerance and Pb precipitation, was isolated from HM-contaminated soil at an abandoned mine site. The bacterium was identified as Pseudomonas fluorescens based on 16S rDNA sequencing. The JH 70-4 strain induced precipitation of Pb as PbS nanoparticles, confirmed by X-ray diffraction. Solution pH, incubation time, and Pb concentration influenced removal and PbS formation. Inoculating contaminated soil with JH 70-4 decreased Pb availability; exchangeable Pb decreased while organic- and sulphide-bound Pb increased. The toxicity characteristic leaching procedure showed a 65% decrease in Pb in leachate 60 d after inoculating soil with JH 70-4. Shoot and root lengths of Sudan grass grown in the inoculated soil were greater than in the uninoculated soil. Findings suggest that microbial Pb fixation is a viable strategy for remediating soil and promoting plant growth for phytostabilization of contaminated sites.

Biodegradation of BTEX mixture by Pseudomonas putida YNS1 isolated from oil-contaminated soil.

The presence of mixed contaminants, such as BTEX (benzene, toluene, ethylbenzene and xylene isomers) can affect the biodegradation, fate and environmental impacts of each compound. To understand the influence of interactions among BTEX compounds on their biodegradation, four bacteria were isolated from oil-contaminated soil and assayed for BTEX biodegradation in vitro. The isolate exhibiting maximum biodegradation was identified as Pseudomonas putida based on the 16S rDNA sequence. The biodegradation of the BTEX compounds was greatly influenced by pH, temperature, and salinity. Substrate mixture studies (binary, tertiary and quaternary) revealed that the presence of toluene increased the biodegradation rate of benzene, ethylbenzene, and xylene.

Effects of EMG-triggered FES during trunk pattern in PNF on balance and gait performance in persons with stroke.

BACKGROUND: EMG-triggered functional electrical stimulation (EMG-triggered FES) is one of the effective method for improving task performance and providing movement re-learning of central nervous system. Proprioceptive neuromuscular facilitation (PNF) is a traditional manual therapy that is used as a method to regain normal movement by providing specific training methods. OBJECTIVE: The purpose of this study was to investigate the effect of EMG-triggered FES during trunk pattern in PNF on trunk control, balance, and gait of stroke patients. METHODS: Forty participants were randomly allocated to EMG-triggered FES during PNF trunk pattern group (n = 20) and PNF trunk pattern group (n = 20). This study was a pretest-posttest with a control group design for duration of 4weeks (30 min/5 times/1 week). Outcome measures involved trunk impairment scale (TIS), Berg balance scale (BBS), and dynamic gait index (DGI). RESULTS: In the experimental group and control group, TIS, BBS, and DGI score was significantly increased after intervention. However, there was no significant difference between the two groups in the comparison of the experimental group and the control group according to the amount of change before and after the training. CONCLUSIONS: The results of this study showed that PNF trunk pattern affected the trunk control for stroke patients, and increased trunk control ability was effective in improving balance and walking. In addition, it was found that the EMG-triggered FES applied to the PNF trunk pattern affected the trunk control.

Removal of p-cresol and tylosin from water using a novel composite of alginate, recycled MnO2 and activated carbon.

For sustainable production, there is an urgent need to minimize the adverse environmental impacts of swine farming, which is a major contributor of the pollutants p-cresol and tylosin. Novel reactive composite alginate beads (CAB-MOACs) were fabricated by combining alginate with activated carbon (AC) and MnO2 recovered from spent battery waste and used for efficient removal of p-cresol and tylosin from water. Batch experiments were carried out under varying pH (3-11), temperature (15-50 °C), and agitation speed (50-200 rpm) to understand their effects on removal efficiency. The CAB-MOACs had better removal efficiency for p-cresol and tylosin than alginate beads alone or beads containing only AC or MnO2. Adsorption to CAB-MOACs followed pseudo-second-order kinetics (R2≥0.98) and Langmuir isotherm models (R2≥0.95). CAB-MOACs showed higher removal efficiency (∼99.9% after 10 h) compared to beads containing only immobilized MnO2 (60-70%) or AC (94-96%). Regeneration and reuse performance of the CAB-MOACs was excellent through five cycles, although slightly better for p-cresol than tylosin. With low-cost manufacturing and beneficial utilization of hazardous waste such as spent batteries, the newly developed composite beads show potential as an effective adsorbent for treating wastewater effluent containing emerging contaminants like p-cresol and tylosin. Future studies may focus on product refinement and large-scale testing on actual wastewaters.

Gold nanoparticles mediated coloring of fabrics and leather for antibacterial activity.

Metal gold nanoparticles (AuNPs) were synthesized in situ onto leather, silk and cotton fabrics by three different modules, including green, chemical, and a composite of green and chemical synthesis. Green synthesis was employed using Ginkgo biloba Linn leaf powder extract and HAuCl4 with the fabrics, and chemical synthesis was done with KBH4 and HAuCl4. For composite synthesis, G. biloba extract and KBH4 were used to color and embed AuNPs in the fabrics. The colored fabrics were tested for color coordination and fastness properties. To validate the green synthesis of AuNPs, various instrumental techniques were used including UV-Vis spectrophotometry, HR-TEM, FTIR, and XRD. The chemical and composite methods reduce Au(+) onto leather, silk and cotton fabrics upon heating, and alkaline conditions are required for bonding to fibers; these conditions are not used in the green synthesis protocol. FE-SEM image revealed the binding nature of the AuNPs to the fabrics. The AuNPs that were synthesized in situ on the fabrics were tested against a skin pathogen, Brevibacterium linens using LIVE/DEAD BacLight Bacterial Viability testing. This study represents an initial route for coloring and bio-functionalization of various fabrics with green technologies, and, accordingly, should open new avenues for innovation in the textile and garment sectors.

Microbial inactivation kinetics and mechanisms of carbon-doped TiO2 (C-TiO2) under visible light.

In this study, titanium dioxide nanoparticles doped with carbon (C-TiO2) were synthesized by means of sol-gel methods, and the synthesis was verified by means of X-ray photoelectron spectroscopy. The nanoparticles' photocatalytic disinfection activity of Listeria monocytogenes was tested under UV and visible light. The observed inactivation levels for 150min of visible light exposure with and without UV cutoff filters were 2.10 and 2.45 log, respectively. We also found that traditional reactive oxygen species had insignificant actions on C-TiO2 photocatalysts and that L. monocytogenes inactivation in the C-TiO2 system under visible light was induced in large part by the midgap states (hmid(+)) that was produced photochemically from the visible light response. C-TiO2 was found to accelerate bacterial inactivation (of L. monocytogenes) in the presence of visible light. Our data suggests that the C-TiO2 may be useful in the development of alternative disinfectants for environmental applications.

Simultaneous removal of phenol, Cu and Cd from water with corn cob silica-alginate beads.

Phenol and heavy metals in petroleum waste are environmental and human health concerns, but physicochemical removal is often cost-prohibitive and can produce toxic secondary products and treatment residues. An environmentally benign alternative combines corn cob silica with alginate and immobilized bacteria into beads for treating contaminated water. The concentration of phenol was decreased >92% by Pseudomonas putida YNS1 on aliginate-silica beads (2%, w/v) after equilibrating for 96h with water containing 214mg phenol/L. GC-MS analysis indicated formation of benzoquinone and other polar products. Beads containing corn cob silica decreased Cu concentrations by 84-88% and Cd by 83-87% within 24h. In a mixture of 114mg phenol, 43mg Cu and 51mg Cd/L, phenol removal (93% within 96h) only occurred with beads containing the silica and bacterial strain. Beads containing corn cob silica removed >97% of the Cu and >99% of the Cd, critical for reducing toxicity to the bacteria. Beads with the immobilized strain removed phenol when zeolite was used instead of corn cob silica, but beads with silica were more effective for Cu and Cd removal. Results show the potential of corn cob silica combined with alginate and immobilized bacteria for removing phenol and heavy metals from contaminated water.

Characterization of lead resistant endophytic Bacillus sp. MN3-4 and its potential for promoting lead accumulation in metal hyperaccumulator Alnus firma.

The aim of this study was to isolate and characterize endophytic bacteria from the roots of the metal hyperaccumulator plant Alnus firma. A total of 14 bacterial endophytes were isolated from root samples and assayed for tolerance to heavy metals. Isolate MN3-4 exhibited maximum bioremoval of Pb and was subsequently identified as Bacillus sp. based on 16S rRNA sequences. The pH and initial metal concentration highly influenced the Pb bioremoval rate. The growth of isolate MN3-4 was moderately altered in the presence of metals. Scanning electron microscopy, energy dispersive spectroscopy, biological-transmission electron microscopy, and Fourier transform infrared spectroscopy studies revealed that isolate MN3-4 had extracellularly sequestered the Pb molecules with little intracellular accumulation. Isolate MN3-4 did not harbor pbrA and pbrT genes. Moreover, isolate MN3-4 had the capacity to produce siderophores and indoleacetic acid. A root elongation assay demonstrated an increase (46.25%) in the root elongation of inoculated Brassica napus seedlings compared to that of the control plants. Obtained results pointed out that isolate MN3-4 could potentially reduce heavy metal phytotoxicity and increase Pb accumulation in A. firma plants.

Crystallization of silver through reduction process using Elaeis guineensis biosolid extract.

This study presents a special, economically valuable, unprecedented eco-friendly green process for the synthesis of silver nanoparticles. The silver nanoparticles were obtained from a waste material with oil palm biosolid extract as the reducing agent. The use of the oil palm biosolid extract for the nanoparticle synthesis offers the benefit of amenability for large-scale production. An aqueous solution of silver (Ag(+) ) ions was treated with the oil palm biosolid extract for the formation of Ag nanoparticles. The nanometallic dispersion was characterized by surface plasmon absorbance measuring 428 nm. Transmission electron microscopy showed the formation of silver nanoparticles in the range of 5-50 nm. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction analysis of the freeze-dried powder confirmed the formation of metallic silver nanoparticles. Moreover, Fourier Transform Infrared Spectroscopy provided evidence of phenolics or proteins as the biomolecules that were likely responsible for the reduction and capping agent, which helps to increase the stability of the synthesized silver nanoparticles. In addition, we have optimized the production with various parameters.

Removal of zinc by live, dead, and dried biomass of Fusarium spp. isolated from the abandoned-metal mine in South Korea and its perspective of producing nanocrystals.

Bioremediation is an innovative and alternative technology to remove heavy metal pollutants from aqueous solution using biomass from various microorganisms like algae, fungi and bacteria. In this study biosorption of zinc onto live, dead and dried biomass of Fusarium spp. was investigated as a function of initial zinc(II) concentration, pH, temperature, agitation and inoculum volume. It was observed that dried, dead and live biomass efficiently removed zinc at 60 min at an initial pH of 6.0+/-0.3. Temperature of 40 degrees C was optimum at agitation speed of 150 or 200 rpm. The initial metal concentration (10-320 mg L(-1)) significantly influenced the biosorption of the fungi. Overall, biosorption was high with 30-60% by dried, live and dead biomass. In addition to this, the potential of Fusarium spp. to produce zinc nanocrystals was determined by transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction and fourier transform infrared spectroscopy, which showed that dead biomass was not significantly involved in production of zinc nanocrystals.