Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Subject: search.filters.subject.nitrogen

Search Results

Now showing 1 - 10 of 25
  • No Thumbnail Available
    Item
    Nutrient contributions by benthal sludge deposits
    (2009) Bhargava, D.S.; Shrihari, S.
    Settled solids from effluents discharged into a river system, undergoing decomposition at the river bottom, form an appreciable internal nutrient source for the biological activities in the river system. During the stabilization of benthal deposits, a variety of nutrients are released into the overlying waters. The exchange between sediment and overlying waters is a major component of the nitrogen and phosphorous cycles in the natural waters. The releases of such nutrients is a surface phenomenon, regulated by the conditions of benthal sludge layers, flow rate of overlying waters, etc. The rate of ammonia nitrogen release manifested an optimum low value when benthal sludge depth was 0.2 m, but was not influenced by the flow rate of overlying water and h/d ratios. The rate of phosphate release from benthal sludge was independent of depth of benthal sludge, flow rate and h/d ratios. The nutrients in the benthal sludge layers were increasing with time, and were concentrated at a layer 10 cm below the top surface. The nutrients release (percent of nutrient remaining in top benthal sludge layers) decreased with time and became almost constant after about 40 days. The nutrients release under continuously accumulating conditions of benthal sludge and me effects of frequency of addition have been discussed in this paper. The nutrients release was less when the frequency of addition was less.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    Synthesis and desalination performance of Ar+-N+ irradiated polysulfone based new NF membrane
    (2011) Hegde, C.; Isloor, A.M.; Padaki, M.; Wanichapichart, P.; Liangdeng, Y.
    In the last few years, membrane technology has gained more attention from polymer chemists throughout the globe. Nowadays, surface modification of membrane is very useful in biotechnology and food science. In the present investigation, we have synthesized polysulfone based composite nanofiltration (NF) membranes, and characterized these membranes by FT-IR, SEM and membrane performance studies. Surface plasma treatment was carried out by irradiation with argon and nitrogen beams in suitable conditions. It was observed that nitrogen beam caused surface roughness that was more severe than the Ar beam. After irradiation, water contact angle was slightly increased. For pure water permeability, flux increased linearly with the operating pressure. However, for the salt solution, the flux was decreased marginally and salt rejection increased after irradiation due to surface modification. The modification effect was characterized in terms of contact angle, AFM employed roughness measurement and dielectric property. It revealed that irradiated NF membranes showed higher salt rejection and lower flux as compared to the nonmodified membranes. Accordingly, the roughness of the membrane surface intensively affected the performance of RO membrane. © 2010 Elsevier B.V.
  • No Thumbnail Available
    Item
    Synthesis and evaluation of antioxidant, antimicrobial activities of new 2,4-disubstituted thiazoles
    (2012) Malladi, S.; Isloor, A.M.; Peethambar, S.K.; Shivananda, K.N.
    A new series of 2,4-disubstituted thiazole derivatives were synthesized by the reaction of various 3-aryl-1H-pyrazole-4- carbaldehyde thiosemicarbazones (2a-e) and phenacyl bromides. The compounds (3a-n) were characterized by IR, NMR, mass spectra and C, H, N analyses. All the synthesized compounds were screened for their antioxidant and antimicrobial activities. Antioxidant studies revealed that, compounds 3b, 3j and 3n showed significant scavenging activity whereas compounds 3e and 3n exhibited significant antimicrobial activity. The acute oral toxicity study for the compound 3e and 3n have revealed good safety profile till the uppermost dose (2000 mg/kg).
  • No Thumbnail Available
    Item
    Production of Naringinase by a new soil isolate of Serratia Sp.: Effect of different carbon and nitrogen sources
    (2013) Pavithra, M.; Belur, P.D.; Saidutta, M.B.
    Four strains of Naringin degrading bacteria were isolated and tested for naringinase activity. All the four isolates showed extracellular naringinase activity. The one which showed consistently good activity in three different media was selected (2 U/L) and was identified by phenotypic characterization as Serratia Sp. In shake-flask trials, effect of various carbon and nitrogen sources was studied. Among all the carbon sources, glucose enhanced the naringinase production. Peptone supplemented with ammonium nitrate was found to be favourable. Maximum of 9.2 U/L naringinase activity was achieved in the medium comprising naringin, glucose, peptone, ammonium nitrate and salts.
  • No Thumbnail Available
    Item
    Production of naringinase from a new soil isolate, Bacillus methylotrophicus: Isolation, optimization and scale-up studies
    (2014) Mukund, P.; Belur, P.D.; Saidutta, M.B.
    Five strains of naringin-degrading bacteria were isolated and found to be positive for extracellular naringinase activity. The one that showed highest activity in the selective medium was identified by 16S rRNA analysis as Bacillus methylotrophicus. The best combination of carbon-nitrogen source was determined by employing two-level full factorial analyses, comprising 24 experiments in shake flasks. Sucrose-yeast extract showed significant increase in naringinase activity (7.46 U/L) compared to the basal medium. Naringinase production was found to be inducible and naringin was found to be the best inducer among naringin, naringenin, hesperidin, and L-rhamnose. Inoculum size of 2% (v/v) and age of 48 hr favored naringinase and biomass production. Highest naringinase activity of 8 U/L was observed at the initial medium pH of 6. Response surface modeling was applied based on central composite design to determine the effects of three independent variables (sucrose, yeast extract, and naringin) and their mutual interactions. In total, 20 experiments were conducted and a statistical model was developed, which predicted naringinase production of 10.61 U/L. Subsequently, verification experiments were conducted and validity of the model was verified. Bioreactor studies conducted with the optimized medium showed an enzyme production of 12.05 U/L within 34 hr of fermentation. Copyright © Taylor & Francis Group, LLC.
  • No Thumbnail Available
    Item
    Prediction of the presence of topsoil nitrogen from spaceborne hyperspectral data
    (Taylor and Francis Ltd. info@tandf.co.uk, 2015) Gopal, B.; Shetty, A.; Ramya, B.J.
    Conventional methods of soil nitrogen extraction are time consuming, expensive and tedious. Remote sensing and Geographical Information System technologies can be used for the rapid and efficient prediction of the presence of soil nitrogen. However, studies are limited by and large to fields of larger and homogeneous units. This research concentrates on the prediction of topsoil nitrogen from harvested, scattered and small-sized agricultural fields of India using hyperspectral data. Spaceborne hyperspectral Hyperion data are used for the prediction of the presence of nitrogen. Multivariate partial least square regression method was used to predict the presence of nitrogen from reflectance. Reflectance data were pretreated using moving average and Savitzky–Golay filters which resulted in moderate prediction of R2 0.65 and 0.63 for calibration and validation, respectively. It can be inferred that Hyperion data can be effectively used for the prediction of the presence of soil nitrogen with a moderate level of accuracy even in case of scattered fields and fields of sizes approximately equal to the spatial resolution of the satellite. © 2014, © 2014 Taylor & Francis.
  • No Thumbnail Available
    Item
    Multistrain probiotic production by co-culture fermentation in a lab-scale bioreactor
    (Wiley-VCH Verlag info@wiley-vch.de, 2016) Jangra, M.; Belur, P.D.; Oriabinska, L.B.; Dugan, O.M.
    Most commercial probiotic products intended for pharmaceutical applications consist of combinations of probiotic strains and are available in various forms. The development of co-culture fermentation conditions to produce probiotics with the correct proportion of viable microorganisms would reduce multiple operations and the associated costs. The aim of this study was to develop a fermentation medium and process to achieve biomass comprising the desired proportion of two probiotic strains in co-culture. Initially, a quantification medium was developed, and the method was optimized to allow the quantification of each strain's biomass in a mixture. The specific growth rates of Lactobacillus delbrueckii spp. bulgaricus and Lactobacillus plantarum were determined in media with different carbon sources. The inoculum volume was optimized to achieve equal proportion of biomass in co-culture fermentation in test tubes. Next, fermentation was carried out in a 3-L bioreactor. A biomass concentration of 2.06 g/L, with L. delbrueckii spp. bulgaricus and L. plantarum in the ratio of 47%:53% (by weight), was achieved with concomitant production of 12.69 g/L of lactic acid in 14 h. The results show that with careful manipulation of process conditions, it is possible to achieve the desired proportion of individual strains in the final biomass produced by co-culture fermentation. This process may serve as a model to produce multistrain probiotic drugs at industrial scale. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
  • No Thumbnail Available
    Item
    Effect of including the carbon nanotube and graphene oxide on the electrocatalytic behavior of the Ni-W alloy for the hydrogen evolution reaction
    (Royal Society of Chemistry, 2017) Elias, L.; Hegde, A.C.
    The present work reports the electrocatalytic activities of the composite coatings of Ni-W developed using the carbon nanotube (CNT) and graphene oxide (GO). Ni-W-CNT and Ni-W-GO coatings were developed by exploiting the advantages of the composite electrodeposition technique. The effect of CNT and GO on the induced codeposition behavior of the reluctant metal W and the relationship with their electrocatalytic efficiency was studied. The electrocatalytic alkaline water splitting efficiency for the hydrogen evolution reaction (HER) of each of the electrode materials was tested by using cyclic voltammetry (CV) and chronopotentiometry (CP) techniques. Furthermore, the practical utility of each of the electrode materials was evaluated by measuring the amount of H2 gas evolved. The variation in electrocatalytic activity with composition, structure, and morphology of the coatings was examined systematically using XRD, SEM, and EDS analyses. The Ni-W-CNT and Ni-W-GO composite coatings yielded much better electrocatalytic activities for the HER than did the as-coated Ni-W alloy. The obtained results showed Ni-W-CNT composite coating as the best electrode material for alkaline HER, attributed by both increased W content and number of electroactive centres. Moreover, the number of electroactive centres was found to be affected by the homogeneous distribution of CNT in the alloy matrix. © 2017 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
  • No Thumbnail Available
    Item
    Artificial intelligence models for predicting the performance of biological wastewater treatment plant in the removal of Kjeldahl Nitrogen from wastewater
    (Springer Verlag, 2017) Manu, D.S.; Thalla, A.K.
    The current work demonstrates the support vector machine (SVM) and adaptive neuro-fuzzy inference system (ANFIS) modeling to assess the removal efficiency of Kjeldahl Nitrogen of a full-scale aerobic biological wastewater treatment plant. The influent variables such as pH, chemical oxygen demand, total solids (TS), free ammonia, ammonia nitrogen and Kjeldahl Nitrogen are used as input variables during modeling. Model development focused on postulating an adaptive, functional, real-time and alternative approach for modeling the removal efficiency of Kjeldahl Nitrogen. The input variables used for modeling were daily time series data recorded at wastewater treatment plant (WWTP) located in Mangalore during the period June 2014–September 2014. The performance of ANFIS model developed using Gbell and trapezoidal membership functions (MFs) and SVM are assessed using different statistical indices like root mean square error, correlation coefficients (CC) and Nash Sutcliff error (NSE). The errors related to the prediction of effluent Kjeldahl Nitrogen concentration by the SVM modeling appeared to be reasonable when compared to that of ANFIS models with Gbell and trapezoidal MF. From the performance evaluation of the developed SVM model, it is observed that the approach is capable to define the inter-relationship between various wastewater quality variables and thus SVM can be potentially applied for evaluating the efficiency of aerobic biological processes in WWTP. © 2017, The Author(s).