Production and functionality of exopolysaccharides in bacteria exposed to a toxic metal environment.

In this study, the production and compositional analysis of exopolysaccharides produced by Bacillus cereus KMS3-1 grown in metal amended conditions were investigated. In addition, the metal adsorption efficacy of exopolysaccharides (EPS) produced by KMS3-1 strain was evaluated in a batch mode. Increased production of exopolysaccharides by KMS3-1 strain was observed while growing under metal amended conditions (100 mg/L) and also, the yield was in the order of Pb(II)>Cu(II)>Cd(II)>Control. Characterization of EPS using FT-IR, XRD, and SEM analysis revealed that the EPS can interact with metal ions through their functional groups (O‒H, CH, CË­O, C‒O, and C‒CË­O) and assist the detoxification process. Further, equilibrium results were fitted with the Langmuir model and notably, the maximum adsorption capacity (Qmax) of EPS for Cd(II), Cu(II), and Pb(II) found to be 54.05, 71.42, and 78.74 mg/g, respectively. To the best of our knowledge, EPS demonstrating proficient metal adsorption was substantiated by XRD analysis in this study. Owing to good adsorbing nature, the exopolysaccharides could be used as chelating substances for wastewater treatment.

Characterization and toxicology evaluation of zirconium oxide nanoparticles on the embryonic development of zebrafish, Danio rerio.

Zirconia oxide nanoparticles (ZrO2NPs) are known to be one of the neutral bioceramic metal compounds that has been widely used for their beneficial applications in many biomedical areas, in dental implants, bone joint replacements, drug delivery vehicles, and in various industrial applications. To study the effects of ZrO2NPs on zebrafish model, we used early life stages of the zebrafish (Danio rerio) to examine such effects on embryonic development in this species. ZrO2NPs were synthesized by the sol-gel method, size about 15-20 nm and characterized by SEM, EDX, XRD, FTIR, UV-Vis Spectra. In this study, zebrafish embryos were treated with ZrO2NPs 0.5, 1, 2, 3, 4, or 5 µg of nanoparticles/ml during 24-96 hour post fertilization (hpf). The results showed that ≥0.5-1 µg/ml of ZrO2NPs instigated developmental acute toxicity in these embryos, causing mortality, hatching delay, and malformation. ZrO2NPs exposure induced axis bent, tail bent, spinal cord curvature, yolk-sac, and pericardial edema. A typical phenotype was observed as an unhatched dead embryo at ≥1 µg/ml of ZrO2NPs exposure. This study is one of the first reports on developmental toxicity of zebrafish embryos caused by zirconium oxide nanoparticles in aquatic environments. Our results show that exposure of zirconium oxide nanoparticles is more toxic to embryonic zebrafish at lower concentrations. The results will contribute to the current understanding of the potential biomedical toxicological effects of nanoparticles and support the safety evaluation and synthesis of Zirconia oxide nanoparticles.

Development of silica gel-supported modified macroporous chitosan membranes for enzyme immobilization and their characterization analyses.

The present work was aimed at developing stability enhanced silica gel-supported macroporous chitosan membrane for immobilization of enzymes. The membrane was surface modified using various cross-linking agents for covalent immobilization of enzyme Bovine serum albumin. The results of FT-IR, UV-vis, and SEM analyses revealed the effect of cross-linking agents and confirmed the formation of modified membranes. The presence of silica gel as a support could provide a large surface area, and therefore, the enzyme could be immobilized only on the surface, and thus minimized the diffusion limitation problem. The resultant enzyme immobilized membranes were also characterized based on their activity retention, immobilization efficiency, and stability aspects. The immobilization process increased the activity of immobilized enzyme even higher than that of total (actual) activity of native enzyme. Thus, the obtained macroporous chitosan membranes in this study could act as a versatile host for various guest molecules.

Piper nigrum leaf and stem assisted green synthesis of silver nanoparticles and evaluation of its antibacterial activity against agricultural plant pathogens.

Utilization of biological materials in synthesis of nanoparticles is one of the hottest topics in modern nanoscience and nanotechnology. In the present investigation, the silver nanoparticles were synthesized by using the leaf and stem extract of Piper nigrum. The synthesized nanoparticle was characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray analysis (EDAX), and Fourier Transform Infrared Spectroscopy (FTIR). The observation of the peak at 460 nm in the UV-vis spectra for leaf- and stem-synthesized silver nanoparticles reveals the reduction of silver metal ions into silver nanoparticles. Further, XRD analysis has been carried out to confirm the crystalline nature of the synthesized silver nanoparticles. The TEM images show that the leaf- and stem-synthesized silver nanoparticles were within the size of about 7-50 nm and 9-30 nm, respectively. The FTIR analysis was performed to identify the possible functional groups involved in the synthesis of silver nanoparticles. Further, the antibacterial activity of the green-synthesized silver nanoparticles was examined against agricultural plant pathogens. The antibacterial property of silver nanoparticles is a beneficial application in the field of agricultural nanotechnology.

Highly selective CO2 sensing response of lanthanum oxide nanoparticle electrodes at ambient temperature.

Lanthanum oxide nanoparticles (La2O3 NPs) are attractive rare earth metal oxides because of their applications in optical devices, catalysts, dielectric layers, and sensors. Herein, we report room temperature operative carbon dioxide gas sensing electrodes developed by a simple sonication assisted hydrothermal method. The physiochemical, morphological and gas-sensing properties of the prepared nanoparticles were studied systematically and their successful preparation was confirmed with the absence of impurities and high selectivity towards CO2. The fabricated sensor showed a high sensitivity of 40% towards CO2 at 50 ppm, and it can detect concentrations of up to 5 ppm with a quick response time of 6 s and recovery of 5 s. The electrode demonstrated long-term stability of 95% for 50 days when tested with an interval of 10 days. This simple and cost-effective method shows great potential for fabricating room temperature CO2 gas sensors.

Hydrothermal synthesis and characterization of the antimony-tin oxide nanomaterial and its application as a high-performance asymmetric supercapacitor, photocatalyst, and antibacterial agent.

We have synthesized antimony-tin oxide (ATO) nanoparticles chemically for use in antibacterial, photocatalytic, and supercapacitor applications. The XRD pattern reveals the hexagonal structure, while the FTIR spectra validate the functional groups. The agglomerated nanostructures, which are 40-50 nm thick and 100 nm long, are shown in the SEM images as having spherical, cube, square, and rod form morphologies. In a DLS test, ATO has a zeta potential of 28.93/-28.00 mV, demonstrating strong colloidal stability in the suspension. With minimum inhibitory concentrations (MIC) ranging from 25 to 100 g mL-1, ATO is also tested for its antibacterial activity against a variety of Gram-positive and Gram-negative bacteria. Additionally, rhodamine dye was broken down by ATO nanoparticles in 240 minutes with a degradation efficiency of 88 percent. The specific capacitance (C s) and energy density (E) values of ATO nanoparticles further demonstrated their suitability for use in supercapacitors.

In Vivo Type 2 Diabetes and Wound-Healing Effects of Antioxidant Gold Nanoparticles Synthesized Using the Insulin Plant Chamaecostus cuspidatus in Albino Rats.

BACKGROUND: Gold nanoparticles are known for their many applications in the fields of therapeutics and diagnosis. METHODS: This article focuses mainly on the green method of synthesizing gold nanoparticles by using the leaf powder extract of the insulin plant Chamaecostus cuspidatus and on the characterization of developed plant-mediated synthesis of gold nanoparticles. Furthermore, we investigated the free-radical scavenging activity of green-synthesized gold nanoparticles. RESULTS: The free radicals were exhibited in a dose-dependent manner. The 50% inhibition of free radicals by gold nanoparticles showed that it was similar to that of the standard inhibition. Toxicity studies generally examine changes in blood serum chemistry and cell populations in tissue morphology through histologic analysis without inducing any lethal effects in the mouse model, thereby accomplishing sustained control over the progression of diabetes mellitus, which plays a leading role in vascular complications in patients. The treatment by gold nanoparticles of the mice with diabetes for a period of 21 days restored their blood glucose, glycogen and insulin levels. CONCLUSIONS: The use of gold nanoparticles as antidiabetes materials has been achieved. Further studies are required before gold nanoparticle-based drugs are more widely used.

Biosorption of Zn(II) on the different Ca-alginate beads from aqueous solution.

The performance of a new biosorbent system, consisting of a fungal biomass immobilized within an orange peel cellulose absorbent matrix, for the removal of Zn(2+) heavy metal ions from an aqueous solution was tested. The amount of Zn(II) ion sorption by the beads was as follows; orange peel cellulose with Phanerochaete chrysosporium immobilized Ca-alginate beads (OPCFCA) (168.61 mg/g) > orange peel cellulose immobilized Ca-alginate beads (OPCCA) (147.06 mg/g) > P. chrysosporium (F) (125.0 mg/g) > orange peel cellulose (OPC) (108.70 mg/g) > plain Ca-alginate bead (PCA) (98.26 mg/g). The Zn(2+) concentration was 100 to 1000 mg/L. The widely used Langmuir and Freundlich isotherm models were utilized to describe the biosorption equilibrium process. The isotherm parameters were estimated using linear and non-linear regression analysis. The Box-Behnken model was found to be in close agreement with the experimental values, as indicated by the correlation coefficient value of 0.9999.

Statistical optimization of medium components and growth conditions by response surface methodology to enhance phenol degradation by Pseudomonas putida.

In this work, a four-level Box-Behnken factorial design was employed combining with response surface methodology (RSM) to optimize the medium composition for the degradation of phenol by pseudomonas putida (ATCC 31800). A mathematical model was then developed to show the effect of each medium composition and their interactions on the biodegradation of phenol. Response surface method was using four levels like glucose, yeast extract, ammonium sulfate and sodium chloride, which also enabled the identification of significant effects of interactions for the batch studies. The biodegradation of phenol on Pseudomonas putida (ATCC 31800) was determined to be pH-dependent and the maximum degradation capacity of microorganism at 30 degrees C when the phenol concentration was 0.2 g/L and the pH of the solution was 7.0. Second order polynomial regression model was used for analysis of the experiment. Cubic and quadratic terms were incorporated into the regression model through variable selection procedures. The experimental values are in good agreement with predicted values and the correlation coefficient was found to be 0.9980.

Adsorption of reactive dye from an aqueous solution by chitosan: isotherm, kinetic and thermodynamic analysis.

The adsorption of Remazol black 13 (Reactive) dye onto chitosan in aqueous solutions was investigated. Experiments were carried out as function of contact time, initial dye concentration (100-300mg/L), particle size (0.177, 0.384, 1.651mm), pH (6.7-9.0), and temperature (30-60 degrees C). The equilibrium adsorption data of reactive dye on chitosan were analyzed by Langmuir and Freundlich models. The maximum adsorption capacity (qm) has been found to be 91.47-130.0mg/g. The amino group nature of the chitosan provided reasonable dye removal capability. The kinetics of reactive dye adsorption nicely followed the pseudo-first and second-order rate expression which demonstrates that intraparticle diffusion plays a significant role in the adsorption mechanism. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy and entropy of adsorption. The positive value of the enthalpy change (0.212kJ/mol) indicated that the adsorption is endothermic process. The results indicate that chitosan is suitable as adsorbent material for adsorption of reactive dye form aqueous solutions.

A versatile chitosan/ZnO nanocomposite with enhanced antimicrobial properties.

Porous chitosan membrane was fabricated by casting method using silica particles. Simultaneously nano ZnO was synthesized by green-synthesis method using tung ting oolong tea extract. Chitosan membrane was combined with nano ZnO in order to increase its antimicrobial activity. Through observations obtained from various techniques such as XRD, SEM, FT-IR, UV-visible and fluorescence emission analyses, chitosan was seen to be able to incorporate nano ZnO in the nanocomposite membrane. A blue shift (from 360 to 335 nm) was observed in the UV-visible spectrum of nanocomposite and fluorescence emission intensity of nanocomposite was considerably lower than that of nano ZnO. Gram negative organism Klebsiella planticola (MTCC2727) and Gram positive organism Bacillus substilis (MTCC3053) were used to test the antibacterial and antifouling activities of newly synthesized nanocomposite chitosan/ZnO membrane. The nanocomposite chitosan/ZnO membrane promisingly inhibited the bacterial growth when compared with as-synthesized chitosan. Gram negative K. planticola (MTCC2727) was comparatively more susceptible for inhibition than that of Gram positive Bacillus substilis (MTCC3053). In conclusion, nanocomposite obtained in this study showed enhanced antibacterial and antifouling activities. We believed that the enhanced physical properties of nanocomposite achieved by incorporating nano ZnO in the chitosan matrix could be beneficial in various applications.

Use of cellulose-based wastes for adsorption of dyes from aqueous solutions.

Low-cost banana and orange peels were prepared as adsorbents for the adsorption of dyes from aqueous solutions. Dye concentration and pH were varied. The adsorption capacities for both peels decreased in the order methyl orange (MO) > methylene blue (MB) > Rhodamine B (RB) > Congo red (CR) > methyl violet (MV) > amido black 10B (AB). The isotherm data could be well described by the Freundlich and Langmuir equations in the concentration range of 10-120 mg/l. An alkaline pH was favorable for the adsorption of dyes. Based on the adsorption capacity, it was shown that banana peel was more effective than orange peel. Kinetic parameters of adsorption such as the Langergren rate constant and the intraparticle diffusion rate constant were determined. For the present adsorption process intraparticle diffusion of dyes within the particle was identified to be rate limiting. Both peel wastes were shown to be promising materials for adsorption removal of dyes from aqueous solutions.

Microbiological degradation of phenol using mixed liquors of Pseudomonas putida and activated sludge.

This work investigated the biodegradation potential of phenol using mixed liquors of Pseudomonas putida (ATCC 31800) and activated sludge. Experiments were made as a function of solution pH (6-10), temperature (30-36 degrees C), nitrogen source (NH4)2SO4 (0.5-0.8 g/l), and carbon source glucose (0.5-0.8 g/l). Response surface methodology by the Box-Behnken model was used to examine the role of four process factors on phenol degradation. It was shown that a second-order polynomial regression model could properly interpret the experimental data with an R2-value of 0.9997 and an F-value of 3605.45, based on which the maximum degradation of phenol was estimated up to 80.1% within the range examined. Interactions between process parameters and each significance effect on phenol degradation were also discussed.

Antibacterial activity of pH-dependent biosynthesized silver nanoparticles against clinical pathogen.

Simple, nontoxic, environmental friendly method is employed for the production of silver nanoparticles. In this study the synthesized nanoparticles UV absorption band occurred at 400 nm because of the surface Plasmon resonance of silver nanoparticles. The pH of the medium plays important role in the synthesis of control shaped and sized nanoparticles. The colour intensity of the aqueous solution varied with pH. In this study, at pH 9, the colour of the aqueous solution was dark brown, whereas in pH 5 the colour was yellowish brown; the colour difference in the aqueous solution occurred due to the higher production of silver nanoparticles. The antibacterial activity of biosynthesized silver nanoparticles was carried out against E. coli. The silver nanoparticles synthesized at pH 9 showed maximum antibacterial activity at 50 µL.

Genetic ancestor of external antigens of pandemic influenza A/H1N1 virus.

The aim of the present investigation was to discover the genetic relationships of 2009 pandemic novel influenza A/H1N1 virus (NIV) external antigens Hemagglutinin (HA) and Neuraminidase (NA) with other influenza viruses by performing phylogenetic, comparative and statistical analyses. Phylogenetic trees of these two antigens show that the sequences of the NIV viruses are relatively homogeneous and these were derived from several viruses circulating in swine. The phylogenetic tree of HA shows that NIV had the closest relationship with North-American pig lineages whereas NA had with European pig lineages. In both segments, NIVs had the closest genetic relationship with swine influenza virus lineages. It strongly suggests that pigs are the most possible animal reservoir. Comparative analysis shows that among clade A, NIVs had very low genetic divergence as well as high similarity and also suffered strong purifying selection whereas neighbor clade B shows moderate values when compared to those of clades C-F. It indicates that classical swine influenza viruses present in clade B might be an ancestor of NIVs external antigens. The process of re-assortment occurred in classical swine influenza viruses. The mutation sites exclusively fixed in the NIV of swine and human along with vaccine strain provide an important suggestion for disease diagnosis and vaccine research.

Effect of ompR gene mutation in expression of ompC and ompF of Salmonella typhi.

In the present investigation, a total of 50 stool samples were collected from the food handlers to screen the typhoid asymptomatic carriers, positive result was yielded for 2 out of the 50 samples. Salmonella typhi was isolated and identified based on the cultural characteristics on BSA, Macconkey agar, XLD and phylogenetic analysis. The ompR region of these two strains was amplified, sequenced and a Neighbor-Joining algorithm tree of ompR was constructed. The isolates were designated as (Salmonella Strain) SS-3 and SS-5 respectively. The isolates were subjected to mutation using sodium chloride at various osmolarity concentrations in LB broth. Both the wild and mutant Salmonella typhi were used for the isolation of outer membrane protein. The outer membrane protein was isolated and compared with both the wild and mutated Salmonella typhi. The expression of outer membrane protein was showing the variation in the expression which were noticed by using SDS-PAGE. On the basis of the results, it was concluded that the ompR-envZ two component regulatory systems play an important role on the regulation of Vi polysaccharide synthesis in S. typhi, and that one of the environmental signals for this regulation may be osmolarity.

Characterization and phylogenetic analysis of cellulase producing Streptomyces noboritoensis SPKC1.

A cellulase producing strain of Actinomycetes was isolated from soil samples which were collected from Southwest ghats, Kerala, India at a depth of 6-12 inches and Actinomycetes was characterized by morphological, cultural, physiological, chemotaxonomical and phylogenetic analysis. The 16S rRNA region of this strain was amplified and sequenced. The Neighbor-joining and Maximum Parsimony algorithm with topology tree of 16S rRNA was constructed. Based on results of observation and phylogenetic analysis, the strain SPKC1 was proved to belong to the species Streptomyces noboritoensis with cellulase activity. The Carboxy Methyl Cellulose (CMCase) activities of the strain SPKC1 on eighth day an amount of 910 microg/ml of glucose, 210 microg/ml of protein and 850 mg/100 ml of growth (biomass) on ninth day were recorded. In exocellulase activity strain SPKC1 on first day an amount of 500 microg/ml glucose was produced.

Application of artificial neural network model for the development of optimized complex medium for phenol degradation using Pseudomonas pictorum (NICM 2074).

Biodegradation of phenol using Pseudomonas pictorum (NICM 2074) a potential biodegradant of phenol was investigated for its degrading potential under different operating conditions. The neural network input parameter set consisted of the same set of four levels of maltose (0.025, 0.05, 0.075 g/l), phosphate (3, 12.5, 22 g/l), pH (7, 8, 9) and temperature (30 degrees C, 32 degrees C, 34 degrees C) on phenol degradation was investigated and a Artificial Neural Network (ANN) model was developed to predict the extent of degradation. The learning, recall and generalization characteristic of neural networks was studied using phenol degradation system data. The efficiency of the model generated by the ANN, was tested and compared with the results obtained from an established second order polynomial multiple regression analysis (MRA). Further, the two models (ANN and MRA) were used to predict the percentage of degradation of phenol for blind test data. Performance of both the models were validated in the cases of training and test data, ANN was recommended based on the following higher coefficient of determination R (2); lower standard error of residuals and lower mean absolute percentage deviation.

Factor optimization for phenol removal using activated carbon immobilized with Pseudomonas putida.

Removal efficiency of phenol from aqueous solutions was measured using a suspended culture of Pseudomonas putida (ATCC 3180) or the activated carbon on which the microorganisms were immobilized. Experiments were performed as a function of pH (7-9), temperature (30-36 degrees C), and concentrations of glucose (0.5-0.7 g/l) and ammonium sulfate (0.5-0.7 g/l). The Box-Behnken design was applied in a second-degree quadratic, polynomial regression model to identify the significant effects and the interactions among the above four factors. Based on response curve method the conditions for maximizing phenol removal (initially 0.2 g/l) were recognized as pH 7, temperature 30 degrees C, glucose 0.6 g/l, and ammonium sulfate 0.6 g/l. The inhibition effect of carbon and nitrogen sources beyond a concentration of 0.6 g/l on phenol removal was obvious.

Biodegradation and adsorption of phenol using activated carbon immobilized with Pseudomonas putida.

This paper examined the removal efficiency of phenol from aqueous solution using a suspended culture of Pseudomonas putida (ATCC 3180) or the activated carbon on which the microorganism was immobilized. The kinetics of phenol degradation by immobilized and pure cells was studied. Experiments were performed at various phenol concentrations (0.1-0.4 g/L), pH, temperature (30-36 degrees C), and concentrations of glucose (0.5-0.7 g/L) and (NH4)2SO4 (0.5-0.7 g/L). The presence of activated carbon markedly enhanced the degradation efficiency, showing its ability of protecting microbes from confronting shock loads of organic pollutants. Degradation rate increased with increasing substrate concentration and decreased after reaching a maximum, indicating substrate-inhibition kinetics. In addition, the degradation rate for immobilized cells was much higher than that of free cells. The inhibition effect for phenol degradation was described by the Andrews model. The kinetic parameters were also determined.