Faculty Publications

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    Production and characterization of biosurfactant produced by a novel Pseudomonas sp. 2B
    (2012) Aparna, A.; Srinikethan, G.; Smitha, H.
    Biosurfactant-producing bacteria were isolated from terrestrial samples collected in areas contaminated with petroleum compounds. Isolates were screened for biosurfactant production using Cetyl Tri Ammonium Bromide (CTAB)-Methylene blue agar selection medium and the qualitative drop-collapse test. An efficient bacterial strain was selected based on rapid drop collapse activity and highest biosurfactant production. The biochemical characteristics and partial sequenced 16S rRNA gene of isolate, 2B, identified the bacterium as Pseudomonas sp. Five different low cost carbon substrates were evaluated for their effect on biosurfactant production. The maximum biosurfactant synthesis (4.97g/L) occurred at 96h when the cells were grown on modified PPGAS medium containing 1% (v/v) molasses at 30°C and 150rpm. The cell free broth containing the biosurfactant could reduce the surface tension to 30.14mN/m. The surface active compound showed emulsifying activity against a variety of hydrocarbons and achieved a maximum emulsion index of 84% for sunflower oil. Compositional analysis of the biosurfactant reveals that the extracted biosurfactant was a glycolipid type, which was composed of high percentages of lipid (~65%, w/w) and carbohydrate (~32%, w/w). Fourier transform infrared (FT-IR) spectrum of extracted biosurfactant indicates the presence of carboxyl, hydroxyl and methoxyl functional groups. The mass spectra (MS) shows that dirhamnolipid (l-rhamnopyranosyl-l-rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate, Rha-Rha-C 10-C 10) was detected in abundance with the predominant congener monorhamnolipid (l-rhamnopyranosyl-?-hydroxydecanoyl-?-hydroxydecanoate, Rha-C 10-C 10). The crude oil recovery studies using the biosurfactant produced by Pseudomonas sp. 2B suggested its potential application in microbial enhanced oil recovery and bioremediation. © 2012 Elsevier B.V..
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    Influence of planetary ball milling parameters on the mechano-chemical activation of fly ash
    (Elsevier, 2015) Patil, A.G.; Anandhan, S.
    This study illustrates the design of statistical analysis by Taguchi methodology to obtain nanostructured fly ash by planetary ball milling. An orthogonal array and analysis of variance were employed to analyze the effect of milling parameters. A class-F fly ash was subjected to planetary ball milling induced mechano-chemical activation aided by a surfactant. Ball milling parameters, such as ball-to-powder weight ratio, type and quantity of surfactant and type of medium were varied as guided by the Taguchi design. The nanostructured fly ash was characterized by dynamic light scattering, BET surface area analysis, X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, field emission scanning electron microscopy and transmission electron microscopy. The ball-to-powder weight ratio and the surfactant type are the major influencing factors on lower crystallite size and average particle size and higher specific surface area. The surface modification of fly ash was confirmed by FTIR spectroscopy. The nano fly ash produced by this method has a wide application potential in polymer industries as reinforcement in composites. © 2015 Elsevier B.V.
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    Synthesis and characterization of microporous hollow core-shell silica nanoparticles (HCSNs) of tunable thickness for controlled release of doxorubicin
    (Springer Netherlands rbk@louisiana.edu, 2018) Deepika, D.; JagadeeshBabu, J.B.
    Hollow core-shell silica nanoparticles (HCSNs) are being considered as one of the most favorable drug carriers to accomplish targeted drug delivery. In the present study, we developed a simple two-step method, employing polystyrene (PS) nanoparticles (150 ± 20 nm) as a sacrificial template for the synthesis of microporous HCSNs of size 230 ± 30 nm. PS core and the wall structure directing agent cetyl trimethyl ammonium bromide (CTAB) were removed by calcination. Monodispersed spherical HCSNs were synthesized by optimising the parameters like water/ethanol volume ratio, PS/tetraethyl orthosilicate (TEOS) weight ratio, concentration of ammonia, and CTAB. Transmission electron microscopy (TEM) revealed the formation of hollow core-shell structure of silica with tunable thickness from 15 to 30 nm while tailoring the concentration of silica precursor. The results obtained from the cumulative release studies of doxorubicin loaded microporous HCSNs demonstrated the dependence of shell thickness on the controlled drug release behavior. HCSNs with highest shell thickness of 30 nm and lowest surface area of 600 m2/g showed delay in the doxorubicin release, proving their application as a drug carrier in targeted drug delivery systems. The novel concept of application of microporous HCSNs of pore size ~ 1.3 nm with large specific surface area in the field of drug delivery is successful. © 2018, Springer Nature B.V.