Reduction of selenite to red elemental selenium by moderately halotolerant Bacillus megaterium strains isolated from Bhitarkanika mangrove soil and characterization of reduced product

Two Gram (+) bacterial strains, BSB6 and BSB12, showing resistance and potential for Se(IV) reduction among 26 moderately halotolerant isolates from the Bhitarkanika mangrove soil were characterized by biochemical and 16S rDNA sequence analyses. Both of them were strictly aerobic and able to grow in a wide range of pH (4-11), temperature (4-40 °C) and salt concentration (4-12%) having an optimum growth at 37 °C, pH ∼7.5 and 7% salt (NaCl). The biochemical characteristics and 16S rDNA sequence analysis of BSB6 and BSB12 showed the closest phylogenetic similarity with the species Bacillus megaterium. Both the strains effectively reduced Se(IV) and complete reduction of selenite (up to 0.25 mM) was achieved within 40 h. SEM with energy dispersive X-ray and TEM analyses revealed the formation of nano size spherical selenium particles in and around the bacterial cells which were also supported by the confocal micrograph study. The UV-Vis diffuse reflectance spectra and XRD of selenium precipitates revealed that the selenium particles are in the nanometric range and crystalline in nature. These bacterial strains may be exploited further for bioremediation process of Se(IV) at relatively high salt concentrations and green synthesis of selenium nanoparticles.     

Synthesis and Evaluation of Mechanical Property of Chitosan/PVP Blend Through Nanoindentation-A Nanoscale Study

Journal of Polymers and the Environment - Biocompatible chitosan/PVP blends of different weight ratios were prepared by the solution casting method. The blends were characterized for morphology,...     

Irrigation with domestic wastewater: responses on growth and yield of ladyfinger Abelmoschus esculentus and on soil nutrients

Domestic wastewater is generated continuously and in large quantities. It can serve as an alternative water nutrient source for irrigation. In the present study Abelmoschus esculentus L. (Ladyfinger) was irrigated using untreated wastewater (T1), treated wastewater (T2) and rainwater (T3) in pot experiments. The effect was seen on nutrient fortication, growth and yield of the plant and the nutrient status of the soil. Additionally the build up of Cr, Cu and Zn from the irrigation water were anlayzed in different parts of the plant biomass and in the soil. The sapling survival rate was found to be 87% in T1 followed by T2 and T3. Root shoot ratio under different treatments was found in the order T3 (0.46) >T2 (0.35) >T1 (0.31). The chlorophyll a, b and carotene content in the leaves (mg g(-1)) was found to be 6.3, 0.5, 0.9 under T1, 4.8, 0.4, 0.8 under T2 and 3.2, 0.3, 0.5 under T3 respectively and all the three varied in the order T1>T2>T3. The same trend was found in case of total dry matter (g) T1 (6.3) >T2 (3.7) >T3 (2.3) at p < or = 0.05. There was a considerable increase in nutrients in the soil under T1 and T2 as compared to T3 after final harvest. The organic matter (%), NO3-N and PO4(3-) (mg kg(-1)) content post harvest soil was found to be 3.4, 71, 90 under T1 and 2.9, 52, 63 under T2 respectively. Also, there was an increase in cations Na, K, Ca and Mg in the soil irrigated with T1 and T2 after the final harvest. Thus irrigation with wastewater generally increased soil fertility. Only a small percentage of the heavy metal was bioaccumulated by the plant parts from the irrigation water. There was hardly any metal accumulation in fruits. Bulk of the metal ions remained in the soil.     

Role of bioinoculants and organic fertilizers in fodder production and quality of leguminous tree species

The comparative effect of dual inoculation of native N fixer (Rhizobium) and AM fungi consortia with different organic fertilizers (vermicompost and farm yard manure) on fodder production and quality of two leguminous tree species (Leucaena leucocephala (Lam) de. Wit. and Sesbania sesban (L.) Merr.) in silvopastoral system and their impact on the fodder production of un-inoculated Panicum maximum Jacq. under cut and carry system. After three years of plantation maximum tree survival was in L. leucocephala in all the treatments in comparison to S. sesban while fodder production was more in S. sesban for initial two years and in third year it accelerated in L. leucocephala. Dual inoculation with vermicompost significantly improved fodder production, fodder quality and rhizosphere microflora in L. leucocephala but in S. sesban dual inoculation was at par with single inoculation of N fixer, AM fungi and control (without inoculation). The grass production was higher with L. leucocephala for two years while in third year it was more with S. sesban. The association of Rhizobium with AM fungi in L. leucocephala was better than in S. sesban.     

FDM-based additive manufacturing of recycled thermoplastics and associated composites

Journal of Material Cycles and Waste Management - Hailed since the fourth industrial revolution, three-dimensional (3D) printing or additive manufacturing (AM) has been extensively implemented in...     

Highly efficient solar light-driven BiOX (X=Br/Cl/I) and BiOY heterojunction (Y=Br/Cl) nano photocatalysts in suspended and immobilised forms for malachite green dye wastewater treatment

Environmental Science and Pollution Research - A novel BiOY (Y = Br/Cl) heterojunction nanocatalyst was synthesised chemically and compared with three different BiOX (X = Br/Cl/I) nanocatalysts as...     

Heavy metal pollution and risks in a highly polluted and populated Indian river–city pair using the systems approach

Environmental Science and Pollution Research - A sectorial approach for assessing heavy metal pollution in rivers neglects the inter-relationship between its environmental compartments and thus...     

A multivariate statistical approach for the evaluation of spatial and temporal dynamics of surface water quality from the small reservoir located in the drought-prone area of South-West India: a case study of Tiru reservoir (India)

Environmental Science and Pollution Research - With the use of different multivariate statistical analysis methods, spatio-temporal fluctuations in the water parameters of Tiru reservoir located at...     

Haematological characteristics and bone fluoride content in Bufo melanostictus from an aluminium industrial site

Fluoride concentration in bones and differential haemotological characteristics (RBC, haemoglobin, haematocrit, mean corpusclar haemoglobin and mean corpuscular volume) were measured in amphibians, Bufo melanostictus, collected from fluoride-contaminated and -uncontaminated areas. The average haemoglobin content, total RBC count and haematocrit (%) in blood samples were found to be significantly reduced, while mean corpuscular concentration and volume were significantly elevated in individuals from the contaminated area in comparison to those from the uncontaminated area. Fluoride concentration was approximately 11 times greater in the bones of toads from the contaminated area.     

Study on the fluorescence characteristics of bromadiolone in aqueous and organized media and application in analysis

The fluorescence spectroscopic behavior of bromadiolone (anticoagulant rodenticide), a substituted 4-hydroxycoumarin derivative, was investigated in water and in organized media like micelles and cyclodextrins. A detailed study on various photophysical parameters like fluorescence intensity (I_F), quantum yield (), lifetime (τ) and steady state fluorescence anisotropy (r) of bromadiolone in aqueous and in organized media was carried out. Bromadiolone in aqueous solution was observed to be in an aggregated state, thereby showing weak emission due to self-quenching. Marked enhancement of fluorescence intensity was observed in organized media like micelles and β-cyclodextrin. A preliminary investigation has been done to find out whether this enhancement of fluorescence can be used to develop a sensitive analytical method for determination of bromadialone in aqueous media. A linear relationship between the fluorescence intensity and concentration of bromadiolone was observed in the range of 0.15–7.9 μg ml⁻¹ in cetyltrimethylammonium bromide (CTAB) and 0.5–26.4 μg ml⁻¹ in β-cyclodextrin medium. The lower detection limit was found to be 37 ng ml⁻¹ in presence of CTAB and 23 ng ml⁻¹ in β-cyclodextrin. Comparison with 4-hydroxycoumarin, an unsubstituted analogue, was made.