Faculty Publications

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Publications by NITK Faculty

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    Artificial neural networks model for the prediction of steady state phenol biodegradation in a pulsed plate bioreactor
    (2008) Shetty K, K.V.; Nandennavar, S.; Srinikethan, G.
    Background: A recent innovation in fixed film bioreactors is the pulsed plate bioreactor (PPBR) with immobilized cells. The successful development of a theoretical model for this reactor relies on the knowledge of several parameters, which may vary with the process conditions. It may also be a time-consuming and costly task because of their nonlinear nature. Artificial neural networks (ANN) offer the potential of a generic approach to the modeling of nonlinear systems. Results: A feedforward ANN based model for the prediction of steady state percentage degradation of phenol in a PPBR by immobilized cells of Nocardia hydrocarbonoxydans (NCIM 2386) during continuous biodegradation has been developed to correlate the steady state percentage degradation with the flow rate, influent phenol concentration and vibrational velocity (amplitude x frequency). The model used two hidden layers and 53 parameters (weights and biases). The network model was then compared with a Multiple Regression Analysis (MRA) model, derived from the same training data. Further these two models were used to predict the percentage degradation of phenol for blind test data. Conclusions: The performance of the ANN model was superior to that of the MRA model and was found to be an efficient data-driven tool to predict the performance of a PPBR for phenol biodegradation. © 2008 Society of Chemical Industry.
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    Modelling and simulation of steady-state phenol degradation in a pulsed plate bioreactor with immobilised cells of Nocardia hydrocarbonoxydans
    (2011) Shetty K, V.S.; Verma, D.K.; Srinikethan, G.
    A novel bioreactor called pulsed plate bioreactor (PPBR) with cell immobilised glass particles in the interplate spaces was used for continuous aerobic biodegradation of phenol present in wastewater. A mathematical model consisting of mass balance equations and accounting for simultaneous external film mass transfer, internal diffusion and reaction is presented to describe the steady-state degradation of phenol by Nocardia hydrocarbonoxydans (Nch.) in this bioreactor. The growth of Nch. on phenol was found to follow Haldane substrate inhibition model. The biokinetic parameters at a temperature of 30 ± 1 °C and pH at 7.0 ± 0.1 are ? m = 0.5397 h -1, K S = 6.445 mg/L and K I = 855.7 mg/L. The mathematical model was able to predict the reactor performance, with a maximum error of 2% between the predicted and experimental percentage degradations of phenol. The biofilm internal diffusion rate was found to be the slowest step in biodegradation of phenol in a PPBR. © 2010 Springer-Verlag.
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    Evaluation of feeding strategies for enhanced cell-associated tannase production by serratia ficaria dtc
    (CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Belur, P.D.; Goudar, D.C.
    Batch studies on Cell-associated tannase production showed 2.6 U/L activity in the declining phase of growth in the bioreactor. It was observed that Cell-associated tannase production under declining phase was depending upon the bacterial biomass produced under exponential phase and gallic acid level. The peak production of enzyme was always accompanied by a sharp rise in dissolved oxygen concentration. Based on these observations, fed batch fermentation by feeding a mixture of nutrients (glucose and tryptose) and Dissolved oxygen (DO) based feeding strategy of gallic acid were designed. Nutrient feeding strategy showed 10 U/L of enzyme activity at 14th h of fermentation. DO based feeding strategy of gallic acid resulted in the production of 14.4 U/L enzyme activity in the 12th h of fermentation. The enzyme production rate of 1.2 U/L.h achieved in this mode was 4.6–fold greater than the values observed in batch process and 1.68 fold greater than the productivity achieved by feeding nutrients. Hence, DO based feeding strategy of gallic acid was proved to be an effective strategy for enhanced cell-associated tannase production by Serratia ficaria DTC. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Design and construction of BCH codes for enhancing data integrity in multi level flash memories
    (Inderscience Publishers, 2012) Rajesh Shetty, K.; Ramakrishna, K.; Prashantha Kumar, H.; Sripati, U.
    Flash memories have found extensive application for use in storage devices. The storage capacity and reliability of these devices have increased enormously over the years. With increase in density of data storage, the raw bit error rate (RBER), associated with the storage device increases. Error control coding (ECC) can be used to reduce the RBER to acceptable values so that these devices can be employed to store information in applications where data corruption is unacceptable. In this paper, we describe the synthesis of BCH codes for flash memories based on multi level cell (MLC) concept. This is in continuation of our work on synthesis of BCH codes for improving the performance of flash memories based on single level cells (SLC). The improvement in device integrity resulting from the use of these codes has been quantified in this paper along with computation of parameters which allows modelling of flash memory as an equivalent channel. While synthesising codes, we have adhered to the limitations imposed by the memory architecture. Use of these codes in storage devices will result in considerable enhancement of device reliability and consequently open up many new applications for this class of storage devices. © 2012 Inderscience Enterprises Ltd.
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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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    Production of propyl gallate in nonaqueous medium using cell-associated tannase of Bacillus massiliensis: Effect of various parameters and statistical optimization
    (2013) Aithal, M.; Belur, P.D.
    Enzymatic synthesis of propyl gallate in an organic solvent was studied using cell-associated tannase (E.C. 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as a biocatalyst. The influence of buffer pH and strength, water activity, temperature, biocatalyst loading, gallic acid concentration, and 1-propanol concentration was studied by the one-factor-at-a-time method. Subsequently, response surface methodology was applied based on a central composite design to determine the effects of three independent variables (biocatalyst loading, gallic acid concentration, and 1-propanol concentration) and their mutual interactions. A total of 20 experiments were conducted, and a statistical model was developed, which predicted the maximum propyl gallate yield of 20.28 ?g/mL in the reaction mixture comprising 40.4 mg biocatalyst, 0.4 mM gallic acid, and 6.52 % (v/v) 1-propanol in 9.5 mL benzene at 30°C. The subsequent verification experiments established the validity of the model. Under optimal conditions, 25% conversion of gallic acid to propyl gallate was achieved on a molar basis. The absence of the need for enzyme purification and subsequent immobilization steps and good conversion efficiency makes this enzyme system an interesting one. Reports on the applications of bacterial whole cell systems for synthetic reactions in organic solvents are scarce, and perhaps this is the first report on bacterial cell-associated tannase-mediated esterification in a nonaqueous medium. © 2013 International Union of Biochemistry and Molecular Biology, Inc.
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    Biodegradation of phenol using immobilized nocardia hydrocarbonoxydans in a pulsed plate bioreactor: Effect of packed stages, cell carrier loading, and cell acclimatization on startup and steady-state behavior
    (2013) Shetty K, K.; Yarangali, S.B.; Srinikethan, G.
    The effect of the number of stages and cell carrier loading on the steady-state and startup performance of a continuous pulsed plate bioreactor with glass beads as the cell carrier material for biodegradation of phenol in wastewater using immobilized Nocardia hydrocarbonoxydans has been studied. It was found that the performance of the pulsed plate bioreactor during startup and at steady state can be improved by an increase in cell carrier loading, number of stages, total plate stack height, and with a decrease in plate spacing. The startup time for the continuous bioreactor can be decreased by increasing the number of preacclimatization steps for the cells. The attainment of steady effluent phenol concentration can be considered as an indication of steady state of the continuous bioreactor, as when phenol concentration attained a steady value, biofilm thickness, and the attached biomass dry weight also attained a constant value. © 2013 Copyright Taylor and Francis Group, LLC.
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    Enhancing gallic acid content in green tea extract by using novel cell-associated tannase of Bacillus massiliensis
    (2013) Palabhanvi, B.; Belur, P.D.
    Gallic acid content in green tea extract was enhanced by using a novel cell-associated tannase of Bacillus massiliensis. Biomass that contains tannase was used for this study. The activity of the cell-associated tannase was stable during 1 week of storage in the refrigerator. Response surface methodology was applied based on central composite design to determine the effects of three independent variables (pH, temperature and incubation time) and their mutual interactions. A total of 16 experiments were conducted; and a statistical model was developed, which predicted 475.74mg/L gallic acid production at pH6.2, 36C and incubation period of 16.71h. The subsequent verification experiments confirmed the validity of the model. Under optimal conditions, 84.7% of the total hydrolyzable tannins were converted to gallic acid and glucose. This naturally immobilized tannase was stable enough to be used for up to 12 runs. Practical Applications: The current study shows that naturally immobilized tannase of Bacillus massiliensis can be used instead of artificially immobilized tannase. Such naturally immobilized tannase has many advantages as it avoids expensive and laborious isolation, purification and immobilization. Ease of separation of cell-associated enzyme from the reaction mixture and absence of any detectable extracellular tannase activity after enzymatic treatment are some of the encouraging facts. Stability during storage up to 7 days, 85% tannic acid hydrolyzing efficiency, activity at pH3.5-8.0 and operational stability for 12 runs are some of the interesting features of this naturally immobilized enzyme. However, its application for tea treatment will be limited until Bacillus massiliensis gets "Generally Recognized As Safe" status. It can be employed, however, for production of gallic acid from agro residues and production of propyl gallate. © 2012 Wiley Periodicals, Inc.
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    Synthesis and in vitro biological evaluation of new pyrazole chalcones and heterocyclic diamides as potential anticancer agents
    (Elsevier B.V., 2015) Sankappa Rai, U.; Isloor, A.M.; Shetty, P.; Pai, K.S.R.; Fun, H.-K.
    Synthesis and characterization of new heterocyclic pyrazole chalcones (4a-. e) and diamide (6a-. e) derivatives are described. Pyrazole chalcones were synthesized by the reaction of pyrazole aldehydes and suitable aromatic ketones. Diamides were synthesized by the reaction of phthalic acid and amines. Newly synthesized compounds were characterized by spectral studies and their biological activity was assessed in vitro using MCF-7 (human breast adenocarcinoma) and HeLa (human cervical tumor cells) cell lines. Few of the synthesized molecules inhibited the growth of the human breast cancer cell lines and human cervical tumor cell lines at low micromolar to nanomolar concentrations. © 2014 King Saud University.
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    Differential delivery of vincristine to A549 cells using Chitosan capped silver nanoparticles under the pH trigger
    (American Scientific Publishers order@aspbs.com, 2017) Venkatramanan, V.; Arulvel, A.; Bose, R.; Arumugam, G.K.S.
    This study reports chitosan capped biogenically synthesized silver nanoparticles (Chit@AgNPs) of Diameter=12 nm for efficient delivery of vincristine (VCR) to A549 cells under the pH trigger. About 48% w/w of VCR could be loaded to Chit@AgNP without any conjugation system. The infrared spectroscopy indicated the presence of abundant quantities of the hydroxyl group on the surface of VCR loaded Chit@AgNP and it was confirmed by its negative zeta potential (-11.7 mV). Under in vitro condition, the release of VCR from Chit@AgNP into aqueous solution strictly followed first order kinetics with high preference to acidic pH. Significant cytotoxicity was observed in A549 cells than MDCK cells at p > 0-05 when incubated with VCR loaded Chit@AgNP, promoting high specificity towards cancer cells.