Enhanced bactericidal and in vivo wound healing potential of biosynthesized zinc oxide nanoparticles from psyllium mucilage

The multifunctional zinc oxide nanoparticles are synthesized using a cost-effective, efficient, eco-friendly, simple, and clean synthesis approach. Herein, we reported the antibacterial and wound healing potential of zinc oxide nanoparticles (ZnO-NPs) prepared using psyllium gel (PG) as the reducing and stabilizing agent. The PG-mediated zinc oxide nanoparticles (PG-ZnO-NPs) were characterized using UV–Vis, photoluminescence (PL), FTIR, XRD, Raman, and SEM. UV–Vis spectral studies confirmed the surface plasmonic resonance (SPR) band at 364 nm. PL results demonstrated the fluorescent or emission nature of PG-ZnO-NPs. FTIR analysis confirmed characteristic peaks at 873.82 and 619.88 cm⁻¹ due to the tetrahedral coordination of zinc and the formation of the Zn-O bond. XRD and Raman confirm the formation of PG-ZnO-NPs, whereas SEM analysis revealed PG-ZnO-NPs are rod-shaped, having hexagonal prism-like bases, and EDX exhibited the elemental composition of PG-ZnO-NPs. The as-synthesized PG-ZnO-NPs possessed prominent microbicidal potential against gram-positive (Bacillus subtilis and Bacillus licheniformis) and gram-negative (Escherichia coli and Salmonella shigella) bacterial strains in terms of zone of inhibition (ZOI), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). In vivo biological investigations with mice show that the synthesized PG-ZnO-NPs possess outstanding biocompatibility and wound healing potential. PG-ZnO-NPs dressing significantly speeds up full-thickness wound repair by triggering a decrease in MMP-1 and MMP-2 and escalating the mRNA levels of collagen types (I & III) and fibronectin. Thus, our work validates that the inclusion of PG-ZnO-NPs in dressing shows excellent potential for acute wound management.     

Isolation and purification of acteoside and isoacteoside from Plantago psyllium L. by high-speed counter-current chromatography

Two isomeric phenylethanoid glycosides, acteoside and isoacteoside were isolated and purified from the seeds of Plantago psyllium L. for the first time by high-speed counter-current chromatography (HSCCC) using a solvent system consisting of ethyl acetate-water (1:1, v:v). By injecting 200 mg of the n-butanol extract of P. psyllium for five consecutive times, the two-step HSCCC procedure yielded a total of 165 mg of acteoside and 17.5 mg of isoacteoside from 978 mg extract. The recovery rates for acteoside and isoacteoside were 90 and 84%, respectively, and the purities were 98 and 94%, respectively. The HSCCC fractions were analyzed by HPLC and the structures were identified by UV, LC-APCI-MS in negative ion mode, and confirmed by NMR experiments.     

Application of Brazilian sawdust samples for chromium removal from tannery wastewater

Brazilian sawdust samples (Caryocar spp.; Manilkara spp.; and Tabebuia spp.) have been used for Cr(VI) adsorption from water. The series of adsorption isotherms were adjusted to modified Langmuir equation. Thermodynamic data of interactions were studied by the calorimetric titration of Cr(VI) in aqueous solution. All liquid/solid interface adsorptions were entalpically and entropically driven. These sawdust samples were also used to remove chromium from tannery wastewater. The application of Caryocar spp.; Manilkara spp.; and Tabebuia spp. reduced the amount of chromium from 2.11 ± 0.18 mg L⁻¹ to 1.15 ± 0.10; 0.29 ± 0.02 and 0.26 ± 0.02 mg L⁻¹, respectively.     

Affinity separation of enzymes from mixtures containing suspended solids

Agarose beads containing immobilized enzymes or affinity ligands have been made magnetically responsive by adsorbing freshly precipitated magnetite on their surface. These beads are used for affinity adsorption of proteins from complex mixtures containing suspended solids. The magnetically responsive beads and the unwanted (diamagnetic) solids are then separated by magnetic filtration. This magnetic adsorption scheme for direct affinity separation of enzymes from mixtures containing suspended solids is compared with a similar, but nonmagnetic, scheme in which the affinity matrix is supported on fiberglass cloth. The enzyme is allowed to adsorb in this matrix, and the matrix is simply removed physically from the suspension to achieve separation from the unwanted solids. The two methods seem comparable in their ability to separate a desired enzymatic activity. The magnetic methods are technically the more complex of the two, but are significantly the more rapid. The efficiency of separation of diamagnetic and ferrimagnetic solids in these biological systems by high gradient magnetic filtration is good.     

A novel magnetite-immobilized cell process for heavy metal removal from industrial effluent

The sorption and desorption of copper (II) (Cu[II]) ions from the wastewater by magnetite-immobilized cells of Pseudomonas putida 5-x with acidic pretreatment were studied. Pretreating cells with 0.6 N HCl was found to enhance greatly the adsorption capacity of biomass up to 85.6 mg/g and had no significant effect on the loss of P. putida 5-x cells during biosorbent pretreatment. The biosorption capacity to Cu²⁺ of magnetite-immobilized cells of P. putida 5-x harvested during various growth phases was also investigated. The experimental results illustrated that the adsorption capacity to Cu²⁺ of P. putida 5-x cultured in sulfate-limiting medium reached maximum during the late stationary growth phase or early death phase, and reached minimum during the log growth phase. The mechanism of copper sequestering by this type of biomass was studied via transmission electron microscopy. A degradation of the peptidoglycan layer of the cell wall was observed in the acidic pretreatment, but no further degradation appeared after the adsorption-desorption cycle. Cu(II) accumulated mostly on the surface of the cell walls and was effectively desorbed by the acidic treatment during the desorption process.

     

Kinetics of removal of dissolved iron from natural water

The relationships of iron(II) oxidation in water using a new type of aerator based on a disk disperser were studied. The oxidation rate constants and the iron(II) to iron(III) half-conversion time were determined. The iron(II) oxidation in water follows a first-order rate equation. Changes in the water quality parameters depending on the conditions of the iron(II) oxidation were analyzed.     

Tamarindus indica mucilage and its acrylamide-grafted copolymer as flocculants for removal of dyes

The application of Tamarindus indica seed mucilage (Tam), a food grade polysaccharide, and its acrylamide grafted copolymer as flocculants was assessed for the first time for removal of various types of dyes from model textile wastewater containing azo, basic, and reactive dyes. Acrylamide grafted T. indica mucilage (Tam-g-PAM) was obtained by ceric ion initiated polymerization technique. A series of contact time experiments were conducted to assess the system variables such as concentrations of mucilage and dyes and pH. These flocculants reduce the dye concentration by flocculation and settling. The grafted copolymer, Tam-g-PAM showed better results for dye removal. The optimal flocculant concentration, which was required to effect flocculation, was independent of dye concentration within the range examined. Both the flocculants performed better for removal of azo dyes than for reactive and basic dyes.     

Effect of ecological factors on conjugal transfer of chromium-resistant plasmid in Escherichia coli isolated from tannery effluent

The influence of total organic carbon (TOC), pH, and mating temperature on transfer of chromium-resistant plasmid between Escherichia coli strains in terms of variation in the number of transconjugants formed and variation in transfer frequency was investigated. In vitro transfer was studied in five chromate-tolerant E. coli strains isolated from tannery effluent using E. coli K12 J62 (Nal^r Lac⁻) as a recipient. Conjugal transfer of different selection markers was observed in three strains. The study was carried out in sterile wastewater. A gradual decrease was observed both in the number of transconjugants and in transfer frequencies as the concentration of TOC in the mating medium descended from 10,095 to 1.2 mg of C/L, obtaining the maximum values with a TOC concentration of 10,095 mg of C/L. The number of transconjugants and the transfer frequency were maximum at 30°C. However, neither the transfer frequency nor the transconjugant number varied significantly in the range of pHs assayed. The strains were also found resistant to different heavy metals and antibiotics. Curing of these strains resulted in loss of one or more resistance markers indicating the plasmid-borne resistance. It is inferred that plasmid transfer by conjugation occurs in wastewater bodies within a wide range of conditions.     

Reticuloendothelial system-potentiating and alkaline phosphatase-inducing activities of Plantago-mucilage A, the main mucilage from the seed of Plantago asiatica, and its five modification products.

Five kinds of chemically modified products were prepared from Plantago-mucilage A, the representative mucous polysaccharide isolated from the seed of Plantago asiatica L., and their reticuloendothelial system-potentiating and alkaline phosphatase-inducing activities have been investigated. Both activities were markedly enhanced when the mucilage was de-O-acetylated. The products obtained by periodate oxidation, controlled Smith degradation, and partial acid hydrolysis under the two conditions were not effective. Structural features of the partial hydrolyzates were elucidated, and it was shown that these products lost all O-acetyl groups, all xylose branches and many hexuronosyl arabinose side chains.     

Crucible atomizer for determining dissolved and suspended forms of elements in natural waters

A model of a specialized microcolumn has been proposed and tested, namely, a crucible atomization microcolumn for electrothermal atomic absorption analysis of natural waters in which the zone of isolation of suspended matter and the zone of dynamic preconcentration of dissolved forms of elements are separated. A direct independent analysis of solid suspended matter and DETATA concentrate is possible upon completion of preconcentration. Such an approach is used to determine suspended and dissolved forms of cadmium and lead in river water and soil groundwater.     

Toxicity assessment of nickel using Aspergillus niger and its removal from an industrial effluent

Chemical analysis of electroplating effluent revealed the presence of very high concentrations of nickel (393 ppm) in the effluent. Bioassay was carried out to test the toxicity of nickel chloride to Aspergillus niger. In contrast to 50% conidial inhibition at 1.7 mM nickel, hyphal extension was affected even at a lower concentration (0.4 mM), suggesting that hyphae are more sensitive than conidia to nickel. An increase in nickel concentration resulted in a proportionate decrease in the hyphal extension. Nickel (II)-resistant mutants of A. niger M1, M2, and M3, were obtained using direct selection, stepwise adaptation, and ultraviolet mutation techniques. Biosorption of Ni (II) by the mutant M3 was 50% more than that of its parent strain.     

Potato peels as solid waste for the removal of heavy metal copper(II) from waste water/industrial effluent

A new sorbent potato peels, which are normally discarded as solid waste for removing toxic metal ion Cu(II) from water/industrial waste water have been studied. Potato peels charcoal (PPC) was investigated as an adsorbent of Cu(II) from aqueous solutions. Kinetic and isotherm studies were carried out by studying the effects of various parameters such as temperature, pH and solid liquid ratios. The optimum pH value for Cu(II) adsorption onto potato peels charcoal (PPC) was found to be 6.0. The thermodynamic parameters such as standard Gibb's free energy (Delta G degrees ), standard enthalpy (Delta H degrees ) and standard entropy (DeltaS degrees ) were evaluated by applying the Van't Hoff equation. The thermodynamics of Cu(II) adsorption onto PPC indicates its spontaneous and exothermic nature. The equilibrium data at different temperatures were analyzed by Langmuir and Freundlich isotherms.     

Use of polyacrylamide-grafted<Emphasis Type="Italic"> Plantago psyllium</Emphasis> mucilage as a flocculant for treatment of textile wastewater

The chemical modification of Plantago psyllium mucilage (Psy), an anionic polysaccharide, was done by grafting polyacrylamide (PAM) chains to prepare a graft-copolymer (Psy-g-PAM). It was synthesized in the presence of nitrogen using ceric ammonium nitrate–nitric acid redox initiator and characterized by IR spectroscopy, scanning electron microscopy and viscosity measurements. This grafted copolymer was tested for its flocculation efficiency in textile wastewater by the standard Jar test method. The effects of polymer concentration, pH and contact time on the percentage removal of solid wastes [total dissolved solids (TDS) and suspended solids (SS)] and color from textile effluent are reported. The optimum dose was found to be 1.6 mg l^–1, at which maximum solid removal (SS and TDS) was seen. The most suitable pH for TDS and color removal was neutral (7.0) and for SS removal alkaline pH (9.2) was found to be most suitable. The optimum treatment duration for solid waste removal was 5 h. The X-ray diffraction analysis of Psy-g-PAM and solid waste before and after treatment suggests the interaction of the solid waste and Psy-g-PAM copolymer.     

The online removal of dissolved oxygen from aqueous solutions used in voltammetric techniques by the chromatomembrane method

The applicability of the chromatomembrane method for the removal of dissolved oxygen from solvents used in voltammetric measurements was investigated. The chromatomembrane cell combined with a flow-through system allows an online deaeration of solutions. These experiments employed a mercury film electrode as working electrode and differential pulse anodic stripping voltammetry as the measuring method. Different eluents with adequate supporting electrolyte (without analyte) were measured to determine the background current, whether any contribution of oxygen is detectable. Voltammograms of eluents deaerated with the chromatomembrane method are compared to those of eluents purged with nitrogen for several minutes immediately before the measurement. No differences in the background currents can be observed when defined flow rates of eluent and nitrogen are maintained. Determinations of cadmium and lead even indicate the high efficiency of this method.     

Isolation and characterization of phenolic antioxidants from Plantago herb

Seven phenolic compounds, including a new phenylethanoid glycoside, were isolated from the ethyl acetate fraction of an aqueous ethanol extract of Plantago Herb (whole part of Plantago asiatica L.), which showed significant antioxidative activity. The new compound was characterized as 2-(3,4-dihydroxyphenyl)ethyl 3-O-β-D-allopyranosyl-6-O-caffeoyl-β-D-glucopyranoside on the basis of spectral and chemical evidence, and its antioxidant activity was comparable to that of tea catechins.