Faculty Publications

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    Isolation of Thiobacillus sp from aerobic sludge of distillery and dairy effluent treatment plants and its sulfide oxidation activity at different concentrations
    (Triveni Enterprises, 2007) Ravichandra, P.; Mugeraya, G.; Rao, A.G.; Ramakrishna, M.; Jetty, A.
    In the present study two strains of Thiobacillus sp were isolated from aerobic sludge of distillery and dairy effluent treatment plant using standard methods of isolation and enrichment. Experiments were conducted using isolated cultures in batch bioreactor with initial sulfide concentration of 75 and 150 mg/l. The effect of initial sulfide concentration on the activity of isolated Thiobacillus sp was studied. Sulfide oxidizing capacity was also determined at different initial sulfide concentrations. The results from the study indicate the possible isolation of Thiobacillus cultures from native source and application in the full-scale reactor. © Triveni Enterprises.
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    Production of novel cell-associated tannase from newly isolated Serratia ficaria DTC
    (2010) Belur, P.D.; Gopal, M.; Nirmala, K.R.; Nainegali, N.
    Five strains of tannic acid degrading bacteria were isolated and identified by phenotypic characterization. All the five isolates showed cell-associated activity, whereas only three showed extracellular activity. Serratia ficaria DTC, showing the highest cell-associated activity (0.29 U/l), was selected for further shake-flask studies. Tannase synthesis was growth associated and reached the peak in the late stationary phase of growth. Organic nitrogen sources enhanced the tannase production. Peak tannase production of 0.56 U/l was recorded in the medium having the initial pH of 6. The pH and temperature optima of the enzyme were found to be 8.9 and 35°C, respectively. This is the first report of cell-associated activity in the case of bacterial tannase. Cell-associated tannase of Serratia ficaria DTC could be industrially important from the perspective of its activity at broad temperature and pH ranges, and its unusually high activity at pH 8.9. © The Korean Society for Microbiology and Biotechnology.
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    Design, synthesis and antimicrobial activities of some new quinoline derivatives carrying 1,2,3-triazole moiety
    (2010) Thomas, K.D.; Vasudeva Adhikari, A.V.; Shetty, N.S.
    A new series of [1-(6-methoxy-2-methylquinolin-4-yl)-1H-1,2,3-triazol-4-yl] methanamine derivatives were synthesized starting from 4-methoxyaniline through multi-step reactions. The title compounds 5a-y were prepared by treating the azide intermediate 4 with propargyl bromide and different alkyl/heterocyclic amines in a sequential three component synthesis. All the new compounds were characterized by spectral and elemental analyses. The newly synthesized final compounds were evaluated for their in vitro antibacterial and antifungal activities against pathogenic strains. The preliminary screening results indicated that most of the compounds demonstrated moderate to very good antibacterial and antifungal activities, comparable to the first-line drugs. Twenty five new derivatives of [1-(6-methoxy-2-methylquinolin-4-yl)-1H-1,2,3- triazol-4-yl] methanamine have been synthesized and the most effective compounds have MIC of 6.25 ?g/mL, which are in comparable with present antibiotics. © 2010 Elsevier Masson SAS. All rights reserved.
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    New quinolin-4-yl-1,2,3-triazoles carrying amides, sulphonamides and amidopiperazines as potential antitubercular agents
    (2011) Thomas, K.D.; Vasudeva Adhikari, A.V.; Chowdhury, I.H.; Sumesh, E.; Pal, N.K.
    Three new series of quinoline-4-yl-1,2,3-triazoles carrying amides, sulphonamides and amidopiperazines were synthesized through multi-step reactions. The required intermediate, [1-(6-methoxy-2-methylquinolin-4-yl)-1H-1, 2,3-triazol-4-yl]methanol (2) was prepared by treating 4-azido-6-methoxy-2- methylquinoline (1) with propargyl alcohol. Three different series of compounds were synthesized from this intermediate. All the newly synthesized compounds were characterized by spectral and elemental analyses. The structure of 2 was confirmed by X-ray crystallographic study. Further, the title compounds were evaluated for their in vitro anti-bacterial activity against five different bacterial strains and antimycobacterial activity against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis (ATCC 19420) and Mycobacterium fortuitum (ATCC 19542). Title compounds, 6a, 6d, 6i, 6j, 7e, 10a and 10i were found to be active against Mycobacterium tuberculosis H37Rv strain and could be lead molecules of interest. © 2011 Elsevier Masson SAS.
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    Design, synthesis and docking studies of quinoline-oxazolidinone hybrid molecules and their antitubercular properties
    (2011) Thomas, K.D.; Vasudeva Adhikari, A.V.; Chowdhury, I.H.; Sandeep, T.; Mahmood, R.; Bhattacharya, B.; Sumesh, E.
    New series of quinoline-oxazolidinone hybrid molecules were synthesized based on the preliminary docking studies. All the newly synthesized compounds were characterized by spectral analyses. The newly synthesized compounds were screened for their antimycobacterial properties based on the promising preliminary antibacterial screening results. Amongst tested compounds, compounds 8a, 8j and 13a were active at 0.65 ?g/mL against Mycobacterium tuberculosis H 37Rv strain. The mode of action of these active compounds was carried out by docking of receptor enoyl-ACP reductase with newly synthesized candidate ligands 8a, 8j and 13a. These compounds exhibited well established bonds with one or more amino acids in the receptor active pocket. From the docking studies, compound 8j was considered to be the best inhibitor. © 2011 Elsevier Masson SAS. All rights reserved.
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    Characteristics of a novel Acinetobacter sp. and its kinetics in hexavalent chromium bioreduction
    (2012) Narayani, M.; Shetty K, K.V.
    Cr-B2, a Gram-uegadve hexavalent chromium [Cr(VI)] reducing bacteria, was isolated from the aerator water of an activated sludge process in the wastewater treatment facility of a dye and pigment based chemical industry. Cr-B2 exhibited a resistance for 1,100mg/l Cr(VI) and, similarly, resistance against other heavy metal ions such as Ni2+ (800 mg/l), Cu2+ (600 mg/l), Pb2+ (1,100 mg/l), Cd2+ (350 mg/l), Zn2+ (700 mg/l), and Fe3+ (1,000 mg/l), and against selected antibiotics. Cr-B2 was observed to efficiently reduce 200mg/l Cr(VI) completely in both nutrient and LB media, and could convert Cr(VI) to Cr(III) aerobically. Cr(VI) reduction kinetics followed allosteric enzyme kinetics. The Km values were found to be 43.11 mg/l for nutrient media and 38.05 mg/l for LB media. Vmax values of 13.17 mg/l/h and 12.53 mg/l/h were obtained for nutrient media and LB media, respectively, and the cooperativity coefficients (n) were found to be 8.47 and 3.49, respectively, indicating positive cooperativity in both cases. SEM analysis showed the formation of wrinkles and depressions in the cells when exposed to 800 mg/l Cr(VI) concentration. The organism was seen to exhibit pleomorphic behavior. Cr-B2 was identified on the basis of morphological, biochemical, and partial 16S rRNA gene sequencing chracterizations and found to be Acinetobacter sp. © The Korean Society for Microbiology and Biotechnology.
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    Experimental investigation and artificial neural network-based modeling of batch reduction of hexavalent chromium by immobilized cells of newly isolated strain of chromium-resistant bacteria
    (2012) Shetty K, K.V.; Namitha, L.; Rao, S.N.; Narayani, M.
    The batch bioreduction of Cr(VI) by the cells of newly isolated chromium-resistant Acinetobacter sp. bacteria, immobilized on glass beads and Ca-alginate beads, was investigated. The rate of reduction and percentage reduction of Cr(VI) decrease with the increase in initial Cr(VI) concentration, indicating the inhibitory effect of Cr(VI). Efficiency of bioreduction can be improved by increasing the bioparticle loading or the initial biomass loading. Glass bioparticles have shown better performance as compared to Ca-alginate bioparticles in terms of batch Cr(VI) reduction achieved and the rate of reduction. Glass beads may be considered as better cell carrier particles for immobilization as compared to Ca-alginate beads. Around 90% reduction of 80 ppm Cr(VI) could be achieved after 24 h with initial biomass loading of 14.6 mg on glass beads. Artificial neural networkbased models are developed for prediction of batch Cr(VI) bioreduction using the cells immobilized on glass and Ca-alginate beads. © Springer Science+Business Media B.V. 2011.
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    Synthesis and antimicrobial activity of some new pyrazole containing cyanopyridone derivatives
    (2012) Malladi, S.; Isloor, A.M.; Peethambar, S.K.; Ganesh, B.M.; Goud, P.S.K.
    A series of new 4,6-disubstituted-3-cyano-2-pyridone derivatives (4a-o) were synthesized. The structures of all target molecules (4a-o) have been confirmed by various spectral techniques and elemental analyses. The newly synthesized compounds were screened for antibacterial and antifungal activity and most of the compounds showed significant activity comparable with that of the standard drug. The results revealed that 4b, 4c, 4d, 4g, 4m, 4n and 4o showed good antibacterial activity towards all bacterial strains (Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa) when compared to standard drug streptomycin. Amongst all the compounds, 4c showed moderate antifungal activity against Aspergillus flavus. The acute toxicity study has also been carried out for biologically active compounds and the experimental studies revealed that compounds were safe up to 2000 mg/kg and no deaths of animals were recorded.
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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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    Synthesis, characterization and antimicrobial activity of novel ethyl 1-(N-substituted)-5-phenyl-1H-pyrazole-4-carboxylate derivatives
    (2012) Chandrakantha, B.; Isloor, A.M.; Shetty, P.; Isloor, S.; Malladi, S.; Fun, H.-K.
    In the present study, a novel series of Pyrazole derivatives (3a-m) were synthesized by condensing ethyl-3-(dimethylamino)-2-(phenylcarbonyl)prop-2- enoate with different aromatic and aliphatic hydrazines. These newly synthesized compounds were characterized by NMR, mass spectral, IR spectral studies as well as by C, H, and N analyses. All the newly synthesized compounds were screened for their antibacterial properties against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. Among the screened samples, 3c, 3f, 3k, and 3l have showed excellent antibacterial activity against all the tested bacterial strains as compared to the standard drug Ceftriaxone. Few of the compounds were found to be biologically potent. Molecular structure of compound 3i was confirmed by single crystal X-ray analysis. © Springer Science+Business Media, LLC 2011.