Naba Kumar Mondal

Green synthesis of silver nanoparticles and its application for mosquito control

Objective To synthesize and characterize silver nanoparticles from aqueous root extract of Parthenium hysterophorus (P. hysterophorus) and also to evaluate the potentiality of synthesized silver nanoparticles as larvacidal agent against Culex quinquefasciatus (Cx. quinquefasciatus).

An approach to polymer degradation through microbes

Inertness and indiscriminate uses as well as growing water and land pollution problems have lead to concern about plastics. Present paper investigates the possibility of plastic degradation by microbes isolated from forest soil and automobile washout sludge. The in-vivo degradation was studied by litter bag experiment by taking 1 g of each plastic and buried under forest soil and automobile wash-out sludge at a depth of 15 cm from the surface during the month of September to February, 20102011. An in-vitro experiment was started after collecting the plastic samples from the litter bag experiment and the microbes were isolated from the surface of the plastic. Then the isolated microbes inoculated in the Burk’s medium without carbon source in two sets, one with plastic and the other with polyethylene glycol (PEG). Result showed that no variety of plastic comfortable degraded under burial condition during six months. But interesting result was recorded from Scanning Electron Microscopy (SEM) study. The preliminary screening of biodegradation capability was done by Fourier Transform Infra Red (FTIR) Spectroscopy for surface changes. Again, degradation of PEG by microbes clearly indicates their existence in the said medium. Therefore it can be speculated that microbes has enough potential to degrade plastic with due course of time.

Isolation and characterization of arsenic-resistant bacteria and possible application in bioremediation

Highlights • Isolation of two rod-shaped Gram-positive bacteria.• Isolates tolerate up to 4500 ppm and 550 ppm concentration of arsenate and arsenite.• Bacteria mediated arsenic bioremediation.

Evaluation of integrated nutrient management on boro rice in alluvial soil and its impacts upon growth, yield attributes, yield and soil nutrient status

A field trial was conducted during 2009 to 2011 to study the effect of inorganic fertilizer, vermicompost, phosphate solubilizing bacteria (PSB) and Azotobacter on the yield of boro rice (winter rice) and its impacts upon soil nutrient status and grain uptake. The highest yield attributes were recorded with full recommended dose of inorganic fertilizer along with vermicompost at 2.5 t ha−1, PSB and Azotobacter, which was at par with 75% of inorganic fertilizer along with vermicompost at 2.5 t ha−1 and PSB and Azotobacter. Application of PSB and Azotobacter significantly increased available phosphorus and nitrogen in soil. Uptake of micronutrients in grain was in the order of Fe > Mn > Zn > Cu. Micronutrient status in soil was also significantly influenced by the different doses of inorganic, organic and biofertilizers.

Predictability by Box-Behnken model for carbaryl adsorption by soils of Indian origin

This study was undertaken to investigate the adsorption capacity of carbaryl on four Indian soils with different physiochemical properties. A batch adsorption study was carried out in order to evaluate the maximum adsorption capacity of carbaryl using a Response Surface Methodology (RSM). The effects of operating parameter such as initial carbaryl concentration (1–20 mgL−1), adsorbent dosage (0.5–6 g) and contact time (10–180 min) were examined. The proposed quadratic model for Box-Behnken design fits very well to the experimental data because it may be used to navigate design space according to ANOVA results. The regression co-efficient (R2) of the models developed and the results of validation experiments conducted at optimal conditions strongly suggests that the predicted values are in good agreement with experimental results. Contour and response surface plots are used to determine the interactions effects of main factors and optimal conditions of the process. The experiment can be utilized as a guideline for better understanding of carbaryl adsorption onto soil under different operating conditions. The results show that the forest soil is most efficient in binding carbaryl (Sevin) than the other types of soil tested.

Optimization of Cr(VI) biosorption onto Aspergillus niger using 3-level Box-Behnken design: Equilibrium, kinetic, thermodynamic and regeneration studies

Heavy metal biosorption is an efficient technology for the decontamination of metal from industrial waste water. The present study focused on exploration of Aspergillus niger towards removal of Cr(VI) from aqueous solution. The influence of different experimental parameters—initial pH, adsorbent dose, initial concentration, contact time, shaking speed, temperature, and their combined effect during Cr(VI) adsorption—was investigated by means of response surface methodology based on four factorial Box–Behnken experimental design. Optimized values of initial Cr(VI) concentration, pH, adsorbent dose, and contact time were found as 33.33 mg/L, 4.6, 1.0 g/L, and 48.45 min, respectively. A. niger showed the highest adsorption capacity 11.792 mg/g at initial pH 2.0. Equilibrium data fitted well to the Temkin and Freundlich isotherms. Cr(VI) biosorption showed Pseudo-second order rate kinetics. The activation energy of the adsorption was estimated as 2.9 × 10−3 kJ/mol. Thermodynamics properties of the Cr(VI) biosorption was spontaneous in nature. Desorption study showed that nearly 94% of the Cr(VI) adsorbed on A. niger could be desorbed using 0.5 M EDTA.

Soil enzyme activities in dependence on tree litter and season of a social forest, Burdwan, India

The study was done to evaluate enzyme activities (amylase, cellulase and invertase) from the soils of different vegetation sites, with seasonal variation, of social forest, Burdwan, India. Study results showed significant lower enzymatic activities in the subsoil compared to those of the topsoil. The seasonal variations indicated that amylase, cellulase and invertase enzyme activities had reached peaks during the rainy seasons in different soil depths. Amylase activity was highest in Tectona litter containing soil in all seasons in both the soil layers. All the three enzyme activities have shown significant positive correlation with available nitrogen (p < 0.05) and available phosphorous (p < 0.05) during rainy season in both the soil depths. Correlation study revealed that soil organic carbon was positively correlated with cellulase and invertase activities except in the Anacardium vegetation site in the topsoil during rainy season. Irrespective of the seasons and the depths of soil, control site without vegetation showed much lower levels of organic carbon and enzyme activity compared to those of the experimental sites. Therefore, it is concluded that carbon transformation will be higher during rainy season in the vegetation sites of forest soil under such agroclimatic conditions.

Seasonal variation of soil enzymes in areas of fluoride stress in Birbhum District, West Bengal, India

Abstract Soil enzyme activities provide a unique biochemical means for assessing soil function as an indicator of soil fertility, which can be altered by a profusion of fluoride in the soil and seasonal changes. Seven sites were chosen in the fluoride-affected area of Nasipur, Birbhum District, West Bengal, India, to compare seasonal changes in enzymes (urease, amylase, cellulase and invertase), fluoride content, physicochemical characteristics and the availability of microbes in the soil with a control. The activity of all the enzymes varied with season. Urease had greater activity in the summer, followed by winter; it showed marginal differences from the control area during the winter (p < 0.002) and summer (p < 0.110) but a significant (p < 0.000) difference during the rainy season. Soil pH had a negative impact on urease activity during both winter and summer. Cellulase activity was accelerated by the organic matter and organic carbon content of the soil. Fluoride therefore had the greatest activity against urease activity during the rainy, summer and winter seasons. The microbial population of the soil also showed a negative impact of fluoride, which may in turn affect the soil enzymes and characteristics.

Influence of indigenous inputs on the properties of old alluvial soil in a mustard cropping system

Field experiments were conducted at the Crop Research and Seed Multiplication Farm of Burdwan University, Burdwan, West Bengal, India, to evaluate the influence of integrated nutrient management on soil physicochemical properties in a mustard (Brassica campestris cv. ‘B9’) cropping system. The experiment was conducted during the winter seasons of 2011–2012 and 2012–2013 in old alluvial soil (pH 6–7). Seven different doses of biofertilizers (Azotobacter and phosphate solubilizing bacteria (PSB)), vermicomposts, organic (cow dung), and chemical fertilizers were applied on mustard in both the experimental seasons. The results indicated an improvement in soil quality by increasing soil porosity and water holding capacity significantly, as well as gradual build-up of the soil micronutrient status after harvesting of the crop. Dual applications of biofertilizers and vermicomposts have contributed significantly to higher soil organic matter, available nitrogen (N), phosphorus (P), and potassium (K) contents as well as micronutrient availability of iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) and subsequently increased the soil health.

An alternative eco-friendly approach for sustainable crop production with the use of indigenous inputs under old alluvial soil zone of Burdwan, West Bengal, India

Experiments were conducted on mustard (Brassica campestris cv.B9) in an old alluvial soil zone of Crop Research and Seed Multiplication Farm, Burdwan University, Burdwan, West Bengal, India, during the winter seasons of 2011–2012 and 2012–2013. The aim was to evaluate the use of vermicompost prepared from municipality waste and Eichhornia mixture and its efficacy on crop growth and yield. Different combined doses of vermicompost, dried cow dung and chemical fertilizer along with Azotobacter and phosphate-solubilizing bacteria compared to full recommended dose of chemical NPK fertilizer (100:50:50) were used to develop an alternative farming technology for sustainable crop production and conservation of natural resources. The variety B9 gave a significantly higher seed yield and oil content along with other growth and yield-contributing factors as well as being the most economically viable option against treatment T4 (i.e. 75% NPK + vermicompost at 2.5 tons per hectare) among all the treatments applied for the experiment and was found to be superior to other treatments in old alluvial soil of Burdwan, India. In both the experimental years, seed yield and oil content were found to be the best for the treatment T4 and was better than using chemical fertilizer.