Institute of Advanced Study in Science and Technology IASST

Guwāhāti, India

Institute of Advanced Study in Science and Technology IASST

Guwāhāti, India
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Chakravarty S.,Institute of Advanced Study in Science and Technology IASST | Datta A.,Assam University | Sen Sarma N.,Institute of Advanced Study in Science and Technology IASST
Journal of Materials Chemistry C | Year: 2017

Polyvinyl alcohol formaldehyde (PVF)-based composites are synthesized and applied for rapid detection and quantification of sulphur dioxide (SO2) vapours by electrical impedance measurements. A series of polymeric composites, namely PVF/single-walled carbon nanotubes (PVFCNTs), PVF/carbon nanoparticles (PVFCNPs), PVF-coumarin-6 (PVFCOU), PVF/thiophene (PVFTH) and PVF/cytochrome-6-oxidase (PVFCY), are synthesized in high yields by a simple one-pot approach. These were characterized by FT-IR, AC conductivity and FESEM. The composites were then used for the impedimetric detection of SO2 vapours, and the sensitivity was found to follow the order: PVFCOU > PVFTH > PVF. The current vs. voltage (I-V) curves further demonstrated a second-order decrease in conduction for PVFCOU upon exposure to SO2 vapours. Amongst the synthesized composites, PVFCOU exhibited an excellent response time of 3 s for 400 ppt SO2, with a limit of detection of 1.15 ppb. Our findings demonstrate, for the first time, an AC electrical impedance-based SO2 detection, using the PVFCOU polymeric composite. In addition, this polymeric composite fulfills the dual function of highly efficient sensing and analyte sequestration. Thus, PVFCOU may be an ideal cost-effective solid-state sensor material for onsite vapour sensing applications. © The Royal Society of Chemistry.


Bordoloi S.,Institute of Advanced Study in Science and Technology IASST | Basumatary B.,Institute of Advanced Study in Science and Technology IASST | Saikia R.,Institute of Advanced Study in Science and Technology IASST | Das H.C.,Oil India Ltd
Journal of Chemical Technology and Biotechnology | Year: 2012

Background: The aim of this study was to assess the suitability of Axonopus compressus for the removal of petroleum hydrocarbons from contaminated soil. An experiment was conducted with crude oil contaminated soil to evaluate the degradation of this crude oil in pots in the presence of A. compressus for 360 days. Study of the degradation of total petroleum hydrocarbon (TPH), its accumulation in roots and shoots, plant growth and biomass production and most probable number (MPN) was conducted at 60 day intervals. Result: In the presence of contaminants, plant biomass and height were significantly reduced. TPH was reduced by 70% in TA (fertilized soil) and 40% in TC (unfertilized soil). In the unvegetated pots, the reduction of TPH was 11% in TB (fertilized soil) and 9% in TD (unfertilized soil), which was attributed to microbial action and natural attenuation. Degradation was significantly greater in vegetated pots than in unvegetated pots (P < 0.05). Conclusion: A. compressus enhanced biodegradation of crude oil in soil under the conditions of this experiment. The addition of fertilizer further enhanced the degradation process. © 2012 Society of Chemical Industry.


Basumatary B.,Institute of Advanced Study in Science and Technology IASST | Saikia R.,Institute of Advanced Study in Science and Technology IASST | Bordoloi S.,Institute of Advanced Study in Science and Technology IASST | Das H.C.,Oil India Ltd | Sarma H.P.,Gauhati University
Journal of Chemical Technology and Biotechnology | Year: 2012

Background: Contamination of soil and sediments with petroleum hydrocarbons (PHCs) is a serious global problem and environmental concern. Therefore, remediation of soil, water, and sediments is a great challenge for research in this field. This study aims to use two types of sedge species, Cyperus odoratus L. and Cyperus laevigatus L. for phytoremediation of crude oil contaminated soil. The study includes the evaluation of plant height, root length, total petroleum hydrocarbon (TPH) degradation in soil, TPH accumulation in plants grown in fertilized and unfertilized pots and most probable number (MPN). Results: The presence of high concentrations of TPH negatively affected the health and survival of plants. A better result for degradation of TPH was found in fertilized soil (C. odoratus: 78%, C laevigatus: 73%) than in unfertilized soil (C. odoratus: 45%, C. laevigatus: 43%) during the 360 day study. In unplanted pots, the reduction of TPH was 11% in fertilized soil and 9% in unfertilized soil. TPH accumulation by plants and MPN were statistically significant. Conclusion: TPH degradation in soil considered together with the accumulation levels in roots and shoots as well as biomass production suggest that these plants could be used for phytoremediation. Furthermore, inorganic fertilizer amendments in soil showed positive effect on petroleum hydrocarbon degradation and its accumulation in plants. © 2012 Society of Chemical Industry.


Choudhury M.,Institute of Advanced Study in Science and Technology IASST | Devi D.,Institute of Advanced Study in Science and Technology IASST
Journal of the Textile Institute | Year: 2017

Muga cocoons are evidenced of possessing heavy deposition of minerals (such as calcium oxalate) on its surface. This mineral deposition restricts reeling of muga fiber in comparison to the cocoons of mulberry silkworm. In this study, we have attempted to wash out the mineral layer using various chemical and natural agents like ethylenediaminetetraacetic acid (EDTA), potassium carbonate, citric acid, extract of Musa balbisiana (‘kolakhar’), and Citrus limon (lemon), respectively. It is observed that both the natural and chemical agents carefully removes the mineral deposition, leaving the gummy sericin substantially intact, preventing entanglement of fibroin brins, and permitting wet reeling with very minimum number of fiber breaks compared to commercial degumming. The removal of granular minerals was evidenced by surface morphology and FTIR spectroscopy of demineralized cocoon fiber. Further, the tensile strength of demineralized fiber showed superiority in contrast to sodium carbonate degummed fiber. Under the implemented experimental conditions ‘kolakhar’ functioned as the most efficient demineralizing agent amongst all. Therefore, the present study demonstrates an improved method for softening wild silk cocoons in contrast to harsh degumming for obtaining long continuous reeled fiber threads with very less number of fiber breaks and enhanced mechanical strength. © 2017 The Textile Institute


Thakur R.,Tezpur University | Thakur R.,Institute of Advanced Study in Science and Technology IASST | Mukherjee A.K.,Tezpur University
Toxicon | Year: 2017

Protease inhibitors are important constituents of snake venom and play important roles in the pathophysiology of snakebite. Recently, research on snake venom protease inhibitors has provided valuable information to decipher the molecular details of various biological processes and offer insight for the development of some therapeutically important molecules from snake venom. The process of blood coagulation and fibrinolysis, in addition to affecting platelet function, are well known as the major targets of several snake venom protease inhibitors. This review summarizes the structure-functional aspects of snake venom protease inhibitors that have been described to date. Because diverse biological functions have been demonstrated by protease inhibitors, a comparative overview of their pharmacological and pathophysiological properties is also highlighted. In addition, since most snake venom protease inhibitors are non-toxic on their own, this review evaluates the different roles of individual protease inhibitors that could lead to the identification of drug candidates and diagnostic molecules. © 2017 Elsevier Ltd


Sen S.,Institute of Advanced Study in Science and Technology IASST | Borah S.N.,Institute of Advanced Study in Science and Technology IASST | Bora A.,Gauhati University | Deka S.,Institute of Advanced Study in Science and Technology IASST
Microbial Cell Factories | Year: 2017

Background: Sophorolipids are one of the most promising glycolipid biosurfactants and have been successfully employed in bioremediation and various other industrial sectors. They have also been described to exhibit antimicrobial activity against different bacterial species. Nevertheless, previous literature pertaining to the antifungal activity of sophorolipids are limited indicating the need for further research to explore novel strains with wide antimicrobial activity. A novel yeast strain, Rhodotorula babjevae YS3, was recently isolated from an agricultural field in Assam, Northeast India. This study was primarily emphasized at the characterization and subsequent evaluation of antifungal activity of the sophorolipid biosurfactant produced by R. babjevae YS3. Results: The growth kinetics and biosurfactant production by R. babjevae YS3 was evaluated by cultivation in Bushnell-Haas medium containing glucose (10% w/v) as the sole carbon source. A reduction in the surface tension of the culture medium from 70 to 32.6 mN/m was observed after 24 h. The yield of crude biosurfactant was recorded to be 19.0 g/l which might further increase after optimization of the growth parameters. The biosurfactant was characterized to be a heterogeneous sophorolipid (SL) with both lactonic and acidic forms after TLC, FTIR and LC-MS analyses. The SL exhibited excellent oil spreading and emulsifying activity against crude oil at 38.46 mm2 and 100% respectively. The CMC was observed to be 130 mg/l. The stability of the SL was evaluated over a wide range of pH (2-10), salinity (2-10% NaCl) and temperature (at 120 °C for time intervals of 30 up to 120 min). The SL was found to retain surface-active properties under the extreme conditions. Additionally, the SL exhibited promising antifungal activity against a considerably broad group of pathogenic fungi viz. Colletotrichum gloeosporioides, Fusarium verticilliodes, Fusarium oxysporum f. sp. pisi, Corynespora cassiicola, and Trichophyton rubrum. Conclusions: The study reports, for the first time, the biosurfactant producing ability of R. babjevae, a relatively lesser studied yeast. The persistent surface active properties of the sophorolipid in extreme conditions advocates its applicability in diverse environmental and industrial sectors. Further, antifungal activities against plant and human pathogens opens up possibilities for development of efficient and eco-friendly antifungal agents with agricultural and biomedical applications. © 2017 The Author(s).


Gogoi N.,Institute of Advanced Study in Science and Technology IASST | Chowdhury D.,Institute of Advanced Study in Science and Technology IASST
Journal of Materials Chemistry B | Year: 2014

Novel carbon dot coated alginate beads (CA-CD) exhibiting superior stability and swelling properties have been successfully prepared. CA-CD show exceptional stability in ambient condition and are stable at room atmosphere and temperature even after 60 days. Moreover, CA-CD show excessive swelling in comparison to calcium alginate (CA) beads. The beads were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and optical microscopy. The CA and CA-CD beads were investigated for their use as pH dependent sustained drug delivery vehicles taking tetracycline (TC) and tetracycline associated with β-cyclodextrin (β-TC) as model drug systems. It was observed that TC loading was 35% and 77% with CA and CA-CD, respectively. Tetracycline associated with β-cyclodextrin (β-TC) shows 48% loading for CA and much greater loading (as high as 90%) for CA-CD. At pH 1, CA-CD and CA beads show maximum drug release with TC cumulative release of 70% and 37% at 96 h, respectively. However, the delivery rates at pH 1 were slower in case of tetracycline associated with β-cyclodextrin (β-TC) loading showing 61% release for CA-CD and 22% for CA after 96 h. Thus, CA-CD can be suitably used as an effective drug delivery vehicle with maximum release obtained at pH 1 emphasizing its use in the gastrointestinal tract where pH is low. Also, the use of β-cyclodextrin with the drug as an inclusion complex renders the CA and CA-CD beads useful for slow and long-term drug administration. This journal is © the Partner Organisations 2014.


Saikia R.R.,Institute of Advanced Study in Science and Technology IASST | Deka S.,Institute of Advanced Study in Science and Technology IASST
Environmental Science and Pollution Research | Year: 2013

Accumulation of oily sludge is becoming a serious environmental threat, and there has not been much work reported for the removal of hydrocarbon from refinery tank bottom sludge. Effort has been made in this study to investigate the removal of hydrocarbon from refinery sludge by isolated biosurfactant-producing Pseudomonas aeruginosa RS29 strain and explore the biosurfactant for its composition and stability. Laboratory investigation was carried out with this strain to observe its efficacy of removing hydrocarbon from refinery sludge employing whole bacterial culture and culture supernatant to various concentrations of sand-sludge mixture. Removal of hydrocarbon was recorded after 20 days. Analysis of the produced biosurfactant was carried out to get the idea about its stability and composition. The strain could remove up to 85 ± 3 and 55 ± 4.5 % of hydrocarbon from refinery sludge when whole bacterial culture and culture supernatant were used, respectively. Maximum surface tension reduction (26.3 mN m-1) was achieved with the strain in just 24 h of time. Emulsification index (E24) was recorded as 100 and 80 % with crude oil and n-hexadecane, respectively. The biosurfactant was confirmed as rhamnolipid containing C8 and C10 fatty acid components and having more mono-rhamnolipid congeners than the di-rhamnolipid ones. The biosurfactant was stable up to 121 °C, pH 2-10, and up to a salinity value of 2-10 % w/v. To our knowledge, this is the first report showing the potentiality of a native strain from the northeast region of India for the efficient removal of hydrocarbon from refinery sludge. © 2013 Springer-Verlag Berlin Heidelberg.


Borah S.N.,Institute of Advanced Study in Science and Technology IASST | Goswami D.,Institute of Advanced Study in Science and Technology IASST | Lahkar J.,Institute of Advanced Study in Science and Technology IASST | Sarma H.K.,Gauhati University | And 2 more authors.
BioControl | Year: 2015

Fusarium oxysporum f. sp. pisi (van Hall) Snyder & Hansen is an important pathogen of pea that causes wilt. The present study was carried out to evaluate the efficacy of rhamnolipid biosurfactant produced by newly isolated Pseudomonas aeruginosa strain SS14 as an antifungal agent against F. oxysporum f. sp. pisi in Pisum sativum L. The bacterial strain P. aeruginosa SS14 was isolated from crude oil contaminated soil and identified by 16S rDNA sequencing. The biosurfactant was characterized as rhamnolipid by FTIR and LC–MS analyses. Treatment of pea seeds and seedlings under natural conditions of light, temperature and humidity with the rhamnolipid at a concentration of 25 µg ml−1 prior to sowing or planting in pathogen laden soil resulted in complete suppression of characteristic wilt symptoms. The results demonstrate the possibility to develop a sustainable and eco-friendly control measure against F. oxysporum f. sp. pisi which is currently not available. © 2014, International Organization for Biological Control (IOBC).


Goswami D.,Institute of Advanced Study in Science and Technology IASST | Handique P.J.,Gauhati University | Deka S.,Institute of Advanced Study in Science and Technology IASST
Journal of Basic Microbiology | Year: 2014

Pokkah boeng disease on sugarcane caused by the fungus Fusarium sacchari results considerable damage to the crop leading to top rot, the most serious and advanced stage of pokkah boeng, where the growing point is killed and the entire top of the plant dies. In the present study, the effect of rhamnolipid biosurfactant as an antifungal agent against F. sacchari to control pokkah boeng disease was investigated. On the basis of surface tension reduction, 12 bacterial isolates were selected as potent biosurfactant producers and eight of them showed antagonistic effect against F. sacchari. Among the eight, the isolate DS9 was found as the effective inhibitor of the fungus in vitro which was further evaluated using its biosurfactant present in whole culture, cell-free culture supernatant and crude biosurfactant at various concentrations. Reductions of fungal growths were found more with crude biosurfactant. By sequencing 16S rRNA, DS9 was identified as P. aeruginosa and the produced biosurfactant was characterized as rhamnolipid by Liquid Chromatography-Mass Spectrometry (LC-MS) analysis. The rhamnolipid biosurfactant inhibits phytopathogenic fungi F. sacchari and therefore seems to be a good biocontrol agent to control pokkah boeng disease of sugarcane. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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