Faculty Publications

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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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    Eclipta prostrata leaf aqueous extract mediated synthesis of titanium dioxide nanoparticles
    (2012) Govindasamy, G.; Rahuman, A.A.; Priyamvada, B.; Khanna, V.G.; Devarepally, D.K.; Jose, P.J.
    Eco-friendly, nontoxic, inexpensive, abundantly available hitherto unreported Eclipta prostrata leaf extract is used for the biosynthesis of titanium dioxide nanoparticles (TiO 2 NPs). The TiO 2 NPs were characterized by FTIR, XRD, AFM and FESEM analysis. FTIR peak implicated the role of carboxyl group OH stretching amine NH stretch in the formation of TiO 2 NPs. XRD characterized in crystallographic plane of rutile phase. AFM showed uneven surface morphology which indicates the presence of both individual and agglomerated nanoparticles. FESEM analysis showed shape in spherical clusters, quite polydisperse and it ranges in size from 36 to 68 nm with calculated average size of 49.5 nm. In this paper, we have demonstrated a novel biological route for the synthesis of TiO 2 NPs. © 2011 Elsevier B.V. All rights reserved.
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    Effect of chelaters on bioaccumulation of Cd (II), Cu (II), Cr (VI), Pb (II) and Zn (II) in Galerina vittiformis from soil
    (2013) Damodaran, D.; Shetty K, K.; Raj Mohan, B.
    Remediation of heavy metal contaminated soil and water streams are of great necessity as heavy metals are toxic and pose hazardous ecological impacts. Low cost mitigation measures like phytoremediation and mycoremediation are commonly employed. Mycoremediation using macro fungi (mushroom) have proven to provide effective tolerance using an efficient accumulation mechanism in removing heavy metals from soil. The current paper reports the heavy metal remediation potential of macro fungi on soil artificially contaminated with 50mgkg-1 of Cu (II), Cd (II), Cr (VI), Pb (II), and Zn (II) ions. Galerina vittiformis belonging to Strophariacea family was found to be effective in removing the heavy metal from the soil under study within 30 days. Both chemical and biological chelaters at 1, 5, and 10mmolkg-1 concentrations were found to increase the mycoremediation potential of the organism. This study showed that G. vittiformis are efficient in remediating heavy metal from contaminated soil and that their remediation potential can be enhanced by the addition of chelaters. © 2013 Elsevier Ltd.
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    Biosynthesis of lead selenide quantum rods in marine Aspergillus terreus
    (2014) Mary Jacob, J.; Mohan Balakrishnan, R.M.; Kumar, U.B.
    Biosynthesis of fluorescent, semiconductor lead selenide (PbSe) quantum rods was initiated in lead and selenium tolerant marine Aspergillus terreus. TEM and SEM images revealed the formation of rod like structures having an average diameter of 59 nm. Compositional analysis using EDAX followed by optical and structural characterization by XRD, UV-vis and FTIR spectrophotometry confirmed the biogenesis of crystalline PbSe nanoparticles with quantum confinement effects. © 2014 Elsevier B.V.
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    Biosynthesis and optimization of silver nanoparticles by endophytic fungus Fusarium solani
    (Elsevier, 2014) Sogra Fathima, B.; Mohan Balakrishnan, R.M.
    A mathematical model for optimization of factors influencing the biosynthesis of silver nanoparticles by an endophytic fungus Fusarium solani was designed. A high determination coefficient R2 of 99.3% was obtained. Structural characterization by UV-vis, TEM, XRD and FTIR revealed the formation of spherical nanoparticles. © 2014 Elsevier B.V.
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    Synthesis of silver nanoparticles using medicinal Zizyphus xylopyrus bark extract
    (Springer Nature, 2015) Babu, B.; Devadiga, A.; Shetty K, V.K.; Saidutta, M.B.
    In the present paper, biosynthesis of silver nanoparticles using Zizyphus xylopyrus bark extract is reported. Z. xylopyrus bark extract is efficiently used for the biosynthesis of silver nanoparticles. UV–Visible spectroscopy showed surface plasmon resonance peaks in the range 413–420 nm confirming the formation of silver nanoparticles. Different factors affecting the synthesis of silver nanoparticles like methodology for the preparation of extract, concentration of silver nitrate solution used for biosynthesis and initial pH of the reaction mixture were studied. The extract prepared with 10 mM AgNO3 solution by reflux extraction method at optimum initial pH of 11, resulted in higher conversion of silver ions to silver nanoparticles as compared with those prepared by open heating or ultrasonication. SEM analysis showed that the biosynthesized nanoparticles are spherical in nature and ranged from 60 to 70 nm in size. EDX suggested that the silver nanoparticles must be capped by the organic components present in the plant extract. This simple process for the biosynthesis of silver nanoparticles using aqueous extract of Z. xylopyrus is a green technology without the usage of hazardous and toxic solvents and chemicals and hence is environment friendly. The process has several advantages with reference to cost, compatibility for its application in medical and drug delivery, as well as for large-scale commercial production. © 2014, The Author(s).
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    ZnS semiconductor quantum dots production by an endophytic fungus Aspergillus flavus
    (Elsevier Ltd, 2016) Uddandarao, P.; Mohan B, R.
    The development of reliable and eco-friendly processes for the synthesis of metal sulphide quantum dots has been considered as a major challenge in the field of nanotechnology. In the present study, polycrystalline ZnS quantum dots were synthesized from an endophytic fungus Aspergillus flavus. It is noteworthy that apart from being rich sources of bioactive compounds, endophytic fungus also has the ability to mediate the synthesis of nanoparticles. TEM and DLS revealed the formation of spherical particles with an average diameter of about 18 nm and 58.9 nm, respectively. The ZnS quantum dots were further characterized using SEM, EDAX, XRD, UV-visible spectroscopy and FTIR. The obtained results confirmed the synthesis of polycrystalline ZnS quantum dots and these quantum dots are used for studying ROS activity. In addition this paper explains kinetics of metal sorption to study the role of biosorption in synthesis of quantum dots by applying Morris-Weber kinetic model. Since Aspergillus flavus is isolated from a medicinal plant Nothapodytes foetida, quantum dots synthesized from this fungus may have great potential in broad environmental and medical applications. © 2016 Elsevier B.V. All rights reserved.
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    Optimised microwave-assisted biosynthesis of silver nanoparticles from Nothapodytes foetida leaf extracts and its anti-microbial activities
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2016) Roopesh, R.; Geedhika, G.; D'Souza, J.; Anandhan, S.; Bhat, K.U.; Jaya M, J.; Fathima B, S.; Mohan Balakrishnan, R.M.
    The present investigation reports the biogenesis of silver nanoparticles (Ag NPs) using extracts of a medicinal plant Nothapodytes foetida. Total phenolic content (TPC) and ferric reducing antioxidant power (FRAP) assay were carried out for the microwave-assisted extract (MAE) of N. foetida using methanol as solvent and the conditions for extraction were optimised by response surface methodology (RSM). The effects of operating variables such as extraction time, temperature and ratio of sample to solvent were studied using central composite design (CCD). A mathematical model with a high determination coefficient (R2) for TPC (0.991) and FRAP (0.995) was obtained. The optimal conditions of extraction for TPC were 48.6 ºC, 23.15 min and 2.04:30 (g/mL) and for FRAP 52.31ºC, 12.32 min and 1.67: 30 (g/mL). Under these conditions, the experimental yields of TPC and FRAP were 2.426 mg gallic acid equivalents (GAE)/g dry powder and 14.985mg of FeSO4·7H2O/g of dry powder, respectively. Ag NPs were characterised using UV–Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The synthesised Ag NPs have also shown potent activity against the human pathogenic Staphylococcus aureus. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
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    Selenium Biosorption and Recovery by Marine Aspergillus terreus in an Upflow Bioreactor
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2016) Raja, C.P.; Jacob, J.M.; Mohan Balakrishnan, R.M.
    Experiments were conducted to study the Selenium (Se) biosorption and recovery by marine Aspergillus terreus in an upflow bioreactor for a period of 8 days. The Se tolerance of the marine fungus was initially confirmed by visual and microscopic observations that evinced intact fungal cells in an Se-amended medium with sparse changes in the spore texture and cellular number by the seventh day of biosorption studies in the upflow bioreactor. Further, the effect of pH and contact time on the percentage of Se biosorption, in an upflow bioreactor containing fungal pellets, was investigated. It was analyzed that pH ranges of 6-7 and a contact time of 5 days resulted in 85-87% biosorption of Se by the fungal biomass. The interaction of the fungus with the induced Se stress in the medium was monitored regularly for studying the uptake of the metalloid and the possible biosynthesis of Se nanoparticles. Analyses using ultraviolet visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies revealed the formation of crystalline Se nanocrystals with an average diameter of 500 nm on the fungal cell wall. Fourier transform infrared (FTIR) spectroscopic analysis indicated the possible involvement of fungal protein groups that aid the binding of the biosorbed Se nanoparticles on to the fungal cell wall. © 2015 American Society of Civil Engineers.
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    Biosynthesis of copper nanoparticles using copper-resistant Bacillus cereus, a soil isolate
    (Elsevier Ltd, 2016) Tiwari, M.; Jain, P.; Raghu Chandrashekar, R.; Narayanan, K.; Bhat, K.U.; Udupa, N.; Rao, J.V.
    Microorganisms are useful systems for the production of biocompatible metal nanoparticles. Copper, an essential element of life, has good therapeutic potential. However, copper lacks suitable form for effective in vivo delivery, which has diminished its applicability. In this study, we produced biosynthesized copper nanoparticles (BCuNps) using a copper-resistant bacterial isolate from copper mine. The organism was able to tolerate >10 mM of copper and when analysed by 16S rRNA technique, showed 100% similarity with Bacillus cereus. BCuNps, produced by this microorganism, in cell-free filtrate, were characterized for surface plasmon resonance (SPR), particle's characteristics, spectroscopic properties and morphology. SPR peaks for BCuNps were recorded between 570–620 and 350–370 nm. BCuNps characteristics, namely particle size distribution, polydispersity index and zeta potential were found to be 11–33 nm, 0.433 and (?) 19.6 mV, respectively. Scanning electron microscope (SEM), transmission electron microscope (TEM) and atomic force microscope (AFM) analyses confirmed the uniform morphology; X-ray diffraction (XRD) spectrum revealed the crystalline nature; and Fourier transform infrared (FTIR) spectrum disclosed the presence of protein with BCuNps. A comparative evaluation of BCuNps with copper sulphate to determine their antimicrobial and cell toxicity levels was undertaken. BCuNps showed better antimicrobial effect and found to be safer against normal cell lines, such as HaCat, Vero and hFOB, than the copper sulphate control. © 2016 Elsevier Ltd