Pinkee Phukon

Synthesis and evaluation of antioxidant and antibacterial behavior of CuO nanoparticles

CuO nanoparticles were synthesized by thermal decomposition methods and characterized by UV-visible spectroscopy, XRD and TEM analysis. The resultant particles are nearly spherical and particle size is in the range of 15-30 nm. The antioxidant behavior of synthesized CuO nanoparticles was evaluated by scavenging free radicals of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH). The free radical scavenging activity of CuO nanoparticles was monitored by UV-visible spectrophotometry. The antibacterial activity of CuO nanoparticles was tested against different bacterial strains. CuO nanoparticles showed efficient antioxidant activity and bactericidal effect against Eschericia coli and Pseudomonas aeruginosa.

Synthesis of ZnO nanoparticles and evaluation of antioxidant and cytotoxic activity.

ZnO nanoparticles were synthesized by thermal decomposition method and were characterized by UV-vis spectroscopy, XRD, SEM, EDX and TEM analysis. The resultant nanoparticles are nearly spherical and size is in the range of 40-50 nm. The antioxidant behavior of ZnO nanoparticles was assessed by scavenging free radicals of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) with varying nanoparticle concentration and time interval individually. The DPPH scavenging activity was monitored by UV-vis spectrophotometer. ZnO nanoparticles were also showing cytotoxic activity which was studied by hemolytic potentiality test.

Enhancing the stability of colloidal silver nanoparticles using polyhydroxyalkanoates (PHA) from Bacillus circulans (MTCC 8167) isolated from crude oil contaminated soil.

Polyhydroxyalkanoate (PHA) was produced by growing Bacillus circulans (MTCC 8167) in the specific detection medium. The identification of the polymer as PHA was confirmed by fluorescence microscopy. The PHA was purified and characterized using FT-IR. The silver nanoparticles (SNP) were synthesized from AgNO3 in the dispersed colloids of PHA (0.085%) using NaBH4 (sodium borohydrate as reducing agent). The stability was tested using wave length scanning with a UV-Vis spectrophotometer and finally with transmission electron microscopy. The PHA stabilized solution was found to be stable for 30 days as against the low stability of silver nanoparticles (SNP) solution alone.

Bio-plastic (P-3HB-co-3HV) from Bacillus circulans (MTCC 8167) and its biodegradation.

Polyhydroxyalkanoates (PHAs) are naturally occurring polyesters synthesized by bacteria for carbon and energy storage and it has commercial potential as bioplastic. The bacterial species Bacillus circulans MTCC 8167, isolated from crude oil contaminated soil, can efficiently produce medium chain length polyhydroxyalkanoates (P-3HB-co-3HV) from cheap carbon sources like dextrose. The molecular mass of P-3HB-co-3HV was reported as 5.1×10(4)Da with polydispersity index of 1.21 by gel permeation chromatography. In the present investigation different bacteria and fungi species were used for testing the biodegradability of the extracted polymer. The FTIR spectra of the biodegraded PHBV film showed a decrease in the peak from 1735 cm(-1) (untreated film) to 1675 cm(-1), and disappearance of a peak present in the control at 2922 cm(-1) indicating the breakdown of ester (>C=O) or O-R group and -C=H bond, respectively. From biodegradability testing, the tested microorganisms were found to have decisive contribution to the biodegradation of P-3HB-co-3HV polymer.

Natural polyhydroxyalkanoate-gold nanocomposite based biosensor for detection of antimalarial drug artemisinin

The worrisome trend of antimalarial resistance has already highlighted the importance of artemisinin as a potent antimalarial agent. The current investigation aimed at fabricating a biosensor based on natural polymer polyhydroxyalkanoate-gold nanoparticle composite mounting on an indium-tin oxide glass plate for the analysis of artemisinin. The biosensor was fabricated using an adsorbing horse-radish peroxidase enzyme on the electrode surface for which cyclic voltammetry was used to monitor the electro-catalytic reduction of artemisinin under diffusion controlled conditions. Electrochemical interfacial properties and immobilization of enzyme onto a polyhydroxyalkanoate-gold nanoparticle film were evaluated, and confirmed by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The differential pulse voltammetric peak current for artemisinin was increased linearly (concentration range of 0.01-0.08μg mL(-1)) with sensitivity of 0.26μAμg mL(-1). The greater sensitivity of the fabricated biosensor to artemisinin (optimum limits of detection were 0.0035μg mL(-1) and 0.0036μg mL(-1) in bulk and spiked human serum, respectively) could be of much aid in medical diagnosis.

Production and statistical optimization of biodiesel from kitchen chimney dump lard

BackgroundThe global upsurge in world energy demand, sharp decline in petrofuels reserves, and greater concerns about the environment has constrained mankind to investigate newer and renewable feedstocks for liquid transportation fuels. Existent bioenergy feedstocks cannot suffice for the petro crude reserves, new feedstock for the same will serve as an incremental step for addressing the long recognized problem of energy supply and simultaneously also support further research endeavors related to green chemistry, feed stock biology and bio-energy research. In this regard, the present investigation aims to highlight kitchen chimney dump lard (a bio-waste), as a prospective feedstock for biodiesel production.ResultsStatistical implication (response surface methodology, RSM) can be helpful in design of experiments for biodiesel production and allied approaches. Biodiesel was produced from KCDL which contains high amount of free fatty acids (acid value 28 mg KOH/gm) by a two stage transesterification process. The biodiesel yield was optimized using RSM for optimal production and the yield was found to be 82% compared to 80% predicted using RSM. The biodiesel was characterized by CHN, GC-MS and FTIR spectroscopy. The fuel properties namely density, viscosity, cloud point, pour point, flash point and calorific value were analyzed to access the quality of the fuel. The results suggest the feasibility of biodiesel production from KCDL.ConclusionProduction of biodiesel from KCDL is feasible and warrants necessary research.