Biosorption was carried out in this study using the biomass of microalgae Scenedesmus sp. as adsorbent for the removal of hexavalent chromium or Cr(VI) from solution. Different relevant parameters ...like initial pH, contact time, initial Cr(VI) concentration, biosorbent dosage, particle size, and temperature were examined to evaluate their effect. They were found to be effective with the maximum of 92.89% Cr loading onto the biomass. The FTIR analysis revealed the presence of easily hydrolyzed functional groups like aldehydes, amides, carboxylic acids, phosphates, and halides, which charged positively below the point of zero charge at pH 2.65. The biosorption proceeded through the anionic adsorption mechanism and followed the pseudo-first order kinetic model. Its feasibility was confirmed as the experimental data closely fitted to both Langmuir and Freundlich isotherms. The biosorption was spontaneous. Its spontaneity increased with the increase of temperature. The positive entropy change suggested the randomness at the solid-liquid interface. This study recommended that the toxic Cr(VI) could be removed from different contaminated water samples in the nearby chromite mines using the microalgae biomass. However, it requires attention in some other sides like activation of biomass, interference of other ions, elevation of the experimental pH, the large biomass generation and harvesting, desorption of the Cr-loaded biomass, and recovery of the energy value of the waste biomass.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Hexavalent chromium (Cr(VI)) in water is a proven carcinogen to different internal and external organs of the living organisms. There are different human activities incorporated to the anthropogenic ...sources in the environment enriching Cr(VI) of high concentration in the water system above the regulatory level. The physical, chemical and biological properties of chromium favour the dissolution in the water environment. This concerns the environmental researcher to tackle and mitigate. Chemical or biological techniques or a combination of the two have been used to remove Cr(VI) from polluted waters. Biological techniques include integrated bioremediation, such as the primary processes of direct bioreduction and biosorption, and secondary processes of microbial fuel cell, biostimulation, surface modified dry biomass and biochar adsorption, and engineered biofilm and cell free reductase. These techniques are used by a wide range of living organisms including bacteria, fungi, plants, plant leaves, plant nuts and algae. This group of living organisms transform and remove Cr(VI) from water during the cellular metabolisms, extracellular activities, physical and chemical adsorptions on the cell surface, and photosynthesis. Variation of different physical, chemical and environmental parameters affecting the efficiency of the bioremediation process have impacted on the design of bioreactors. There has been a recent development of a microbial fuel cell which use the proximity of Cr(VI) reduction as a cathode half cell for the generation of renewable energy and simulation of its’ removal from water.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Organic farming will be a significant approach for farmers in the coming decades due to improved production and the preservation of soil natural properties. Phosphorus is the second most ...macronutrient required for plants to survive. The primary goal of this research was to know the paddy field soil nutritional status and isolate potential PSB bacteria from soil samples, which may aid in the development of a potent biofertilizer for organic farming. 12 soil samples were collected from three districts of Odisha (Kendrapara, Cuttack, Khordha). A laboratory study was conducted to isolate, identify, and characterise phosphate solubilizing bacteria from rice field soil. The morphological and biochemical traits of the PSB strains were evaluated. Four potential PSB strains PR, PA, PD, PS were chosen based on solubilization zone production and abundance in sampling site. The isolates PR had maximum phosphate solubilization index of 2.72 in pikovskaya agar medium and were strongly predominant in all regions. Phosphate solubilization and enhanced germination potential were evident in all four species. When compared to controls, good plant height, dry weight, and fresh weight were confirmed in seed germination assays with all bacterial isolates. The PR strain had the highest rate of germination 96.03%.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Tungsten is an important alloying component for the production of different materials. Its efficient extraction from different sustainable resources is necessary to meet the growing demand in the ...future. In this context, an attempt has been made to recover it from a goldmine overburden sample using the fungal bioleaching technique. The sample contains 0.023% of WO
3
in the form of scheelite. The prospect of bioleaching for tungsten recovery from the sample was evaluated by varying pulp density from 1 to 7% (w/v). The leaching rate of tungsten decreased with the increase of pulp density. The maximum tungsten recovery of 86.8% (w/w) could be achieved at the condition of pulp density, 1% (w/v); pH, 6.8; temperature, 32 °C; speed, 120 rpm; contact time, 10 days. Growth of the fungal strain Aspergillus niger in terms of organic acids production was evaluated during the bioleaching experiment and found to be maximum at the pulp density of 1% (w/v). The leaching kinetics of tungsten followed the chemical control model.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Phosphate-solubilizing bacteria play a vital role in enhancing phosphorus availability for plants by solubilizing inorganic phosphate sources, leading to improved phosphorus, enhanced plant growth, ...and increased productivity. The investigation focused on evaluating the phosphate solubilizing capabilities of selected bacterial isolates on rice under controlled laboratory conditions. A total of 60 soil samples were collected from different districts in Odisha, India, and six phosphate-solubilizing bacteria (PR, PD, PSB19, PSB5, PK, and PSB16) were screened and isolated. PSB5 exhibited the highest P-solubilizing efficiency in NBRIP culture medium. Seed treatments with the bacterial isolate resulted in significant improvements compared to the control group. The treated rice plants exhibited a notable increase in height, ranging from 16.78 ± 0.17 cm to 26.48 ± 0.31 cm, along with a substantial improvement in fresh weight, ranging from 0.82 ± 0.01 gm to 1.82 ± 0.07 gm, an impressive boost in dry weight, ranging from 0.30 ± 0.01 gm to 0.65 ± 0.02 and vigor index from1428.481 to2583.876. Six bacterial isolates were assessed qualitatively for phosphate solubilization and PGP functions, out of which, four highly efficient organisms were identified. The 16S rRNA sequencing identified PR asKlebsiella pneumoniae, PD asBurkholderiaspecies strain EIKU9, PSB19 asBacillus siamensis, and PSB5 asPseudomonas guariconensis, confirming their efficiency.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Advances in applied and industrial microbial biotechnology have opened up many new avenues for application of several microorganisms. A group of certain metal reducers such as the dissimilatory iron ...reducing microorganisms possess an inherent potential to reduce oxidized metals under strict anaerobic/facultative anaerobic condition, thereby opening possibilities to combat environmental pollution. This unique property has invited researchers towards understanding the metabolic regulatory pathways that enables the microbes to thrive under extreme environmental conditions. Currently, dissimilatory iron reducing bacteria (DIRB) is in the focus of researchers to elucidate the specific mechanisms responsible for microbial metal reduction. The recent advances towards understanding the metabolism of iron reduction in
Shewanella
and
Geobacter
, the model DIRB has been covered in this review. It is believed that the metabolic insights into the Fe (III) reduction systems of the model DIRB;
Shewanella
and
Geobacter
(as discussed in the review) can be a basis for metabolic engineering to provide improved practical applications. With the advancement of our existing knowledge on the metabolic processes of the model iron reducers, applications ranging from laboratory to field scale practices can be carried out. DIRB has gained immense interest for its application in the field of bioremediation, electrobiosynthesis, and bioelectronics in this decade. It can therefore be anticipated that the forthcoming years will see more applications of microbial iron reducers based on the existing as well as advanced metabolic informations available in open source literature.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In bone tissue engineering, porous hydroxyapatite (HAp) is used as filling material for bone defects, augmentation, artificial bone graft and scaffold material. The present paper compares the ...preparation and characterization of HAp from fish scale (FS) and synthetic body fluid (SBF) solution. Thermo gravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size analysis of the samples have been performed. The analysis indicates that synthesized HAp consists of sub-micron HAp particle with Ca/P ratio corresponding to FS and SBF 1.62 and 1.71, respectively. MTT assay and quantitative DNA analysis show growth and proliferation of cells over the HA scaffold with the increase in time. The shape and size (morphology) of mesenchymal stem cells after 3 days show a transition from rounded shape to elongated and flattened shape expressing its spreading behavior. These results confirm that HAp bio-materials from fish scale are physico-chemically and biologically equivalent to the chemically synthesized HAp from SBF. Biological HAp, thus, possesses a great potential for conversion of industrial by-product into highly valuable compounds using simple effective and novel processes.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this article a new spent catalyst sample preparation method was implemented for the purpose of molybdenum leaching in a single step. Further molybdenum and vanadium in the leach liquor were ...separated and their concentrations were enriched using the solvent extraction and stripping techniques. The impervious sulfur (S
) layer of the spent catalyst sample was removed using carbon disulfide (CS
). The advantages of S
removal were evaluated by conducting different sets of the Mo leaching experiments and they were further examined by varying different conditions such as three lixiviants, hydrogen peroxide (H
O
) addition, and three leaching parameters. The leaching rate increased in an order, e.g. acetone washed < acetone-CS
washed < acetone washed-H
O
< acetone-CS
washed-H
O
, for the experimental concentration range of different lixiviants with the maximum of 94.8%(w/w) Mo dissolution in a single step. Optimization of the pulp density was important as the interaction of lixiviant molecules with multiple reacting solid particles decreased the driving force of the chemical reactions. The solvent extraction followed by the stripping technique was found to be excellent as the concentration of vanadium and molybdenum enriched from 0.55 to 1.9 M and 0.0448 to 1.08 M, respectively.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
An eco-friendly microbial method for synthesis of silver colloid solution with antimicrobial activity is developed using a fungal strain of
Penicillium purpurogenum
NPMF. It is observed that increase ...in concentration of AgNO
3
increases the formation of silver nanoparticle. At 5 mM concentration highly populated polydispersed nanoparticles form. Furthermore, change in pH of the reaction mixture leads to change in shape and size of silver nanoparticles. At lower pH two peaks are observed in the absorption spectra showing polydispersity of nanoparticles. However, highly monodispersed spherical nanoparticles of 8–10 nm size form with 1 mM AgNO
3
concentration at pH 8. Antimicrobial activity of nanoparticles is demonstrated against pathogenic gram negative bacteria like
Escherichia coli
and
Pseudomonas aeruginosa
, and gram positive bacteria like
Staphylococcus aureus.
The antimicrobial activity of silver nanoparticles obtained at different initial pH show strong dependence on the surface area and shape of the nanoparticles.
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