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Sample records for pixe-aided immobilization study

  1. A comparative study of free and immobilized soybean and horseradish peroxidases for 4-chlorophenol removal: protective effects of immobilization.

    PubMed

    Bódalo, Antonio; Bastida, Josefa; Máximo, M Fuensanta; Montiel, M Claudia; Gómez, María; Murcia, M Dolores

    2008-10-01

    Horseradish peroxidase (HRP) and soybean peroxidase (SBP) were covalently immobilized onto aldehyde glass through their amine groups. The activity yield and the protein content for the immobilized SBP were higher than for the immobilized HRP. When free and immobilized peroxidases were tested for their ability to remove 4-chlorophenol from aqueous solutions, the removal percentages were higher with immobilized HRP than with free HRP, whereas immobilized SBP needs more enzyme to reach the same conversion than free enzyme. In the present paper the two immobilized derivatives are compared. It was found that at an immobilized enzyme concentration in the reactor of 15 mg l(-1), SBP removed 5% more of 4-chlorophenol than HRP, and that a shorter treatment was necessary. Since immobilized SBP was less susceptible to inactivation than HRP and provided higher 4-chlorophenol elimination, this derivative was chosen for further inactivation studies. The protective effect of the immobilization against the enzyme inactivation by hydrogen peroxide was demonstrated.

  2. Silica-encapsulated magnetic nanoparticles: enzyme immobilization and cytotoxic study.

    PubMed

    Ashtari, Khadijeh; Khajeh, Khosro; Fasihi, Javad; Ashtari, Parviz; Ramazani, Ali; Vali, Hojatollah

    2012-05-01

    Silica-encapsulated magnetic nanoparticles (MNPs) were prepared via microemulsion method. The products were characterized by high resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectrum (EDS). MNPs with no observed cytotoxic activity against human lung carcinoma cell and brine shrimp lethality were used as suitable support for glucose oxidase (GOD) immobilization. Binding of GOD onto the support was confirmed by the FTIR spectra. The amount of immobilized GODs was 95 mg/g. Storage stability study showed that the immobilized GOD retained 98% of its initial activity after 45 days and 90% of the activity was also remained after 12 repeated uses. Considerable enhancements in thermal stabilities were observed for the immobilized GOD at elevated temperatures up to 80°C and the activity of immobilized enzyme was less sensitive to pH changes in solution.

  3. Urokinase immobilized on medical polymeric materials: fundamental and clinical studies.

    PubMed

    Ohshiro, T; Kosaki, G

    1980-02-01

    One of the methods of preparing an antithrombogenic material is to immobilize a fibrinolytic enzyme on the surface of a carrier. The clinical trial of such a material must be subject to not only a basic study on the quality of a carrier, the technique of immobilization, and the method of disinfection, but also an in vivo study on its antithrombotic effect. Reported herein is the evaluation of the fibrinolytic ability, at fundamental and clinical levels, of the urokinase that was immobilized on the surface of various polymeric materials. The results were favorable.

  4. Immobilized enzyme studies in a microscale bioreactor.

    PubMed

    Jones, Francis; Forrest, Scott; Palmer, Jim; Lu, Zonghuan; Elmore, John; Elmore, Bill B

    2004-01-01

    Novel microreactors with immobilized enzymes were fabricated using both silicon and polymer-based microfabrication techniques. The effectiveness of these reactors was examined along with their behavior over time. Urease enzyme was successfully incorporated into microchannels of a polymeric matrix of polydimethylsiloxane and through layer-bylayer self-assembly techniques onto silicon. The fabricated microchannels had cross-sectional dimensions ranging from tens to hundreds of micrometers in width and height. The experimental results for continuous-flow microreactors are reported for the conversion of urea to ammonia by urease enzyme. Urea conversions of >90% were observed.

  5. Influence of immobilization strategies on biosensing response characteristics: A comparative study.

    PubMed

    Kaur, Gurpreet; Saha, Shibu; Tomar, Monika; Gupta, Vinay

    2016-01-01

    The immobilization technique plays an important role in fabrication of a biosensor. NiO based cholesterol biosensor has been used to study the effect of various immobilization techniques on the biosensing response characteristics. The biosensors were fabricated by immobilizing cholesterol oxidase on NiO thin films by three different immobilization techniques viz. physisorption, cross-linking and covalent binding. The study reveals a strong dependence of biosensing response on corresponding immobilization technique. The biosensor based on immobilization by covalent bonding shows superior response characteristics as compared to others owing to its zero length. The results highlight the significance of immobilization technique for biosensor fabrication.

  6. Preliminary studies on immobilization of lipase using chicken eggshell

    NASA Astrophysics Data System (ADS)

    Salleh, S.; Serri, N. A.; Hena, S.; Tajarudin, H. A.

    2016-06-01

    A few advantages of enzyme immobilization are reusability of expensive enzyme, improvement of stability and activity compared to crude enzyme. Various organic components can be used as carrier for enzyme immobilization such as chicken eggshell. It can be used as a carrier for immobilization as its mineral component mostly contains of calcium carbonate. In the present study, Tributyrin method was used to test enzyme activity of Rhizomucour Miehei, Candida Antarctica and Candida Rugosa. Rhizomucour Miehei shows the highest enzyme activity (360.8 mol/min/mL lipase) and was used in further experiment. Experiment was continued to study incubation time for lipase immobilization on eggshell (1-4 hours) and reaction time of esterification of sugar ester (0-72 hours). Two hours incubation time for lipase immobilization was observed and gives the highest yield of sugar ester (78.13%). Fructose and stearic acid as substrate was used for the production of sugar ester. The highest percentage of sugar ester production was shown at 36 hours of reaction time.

  7. In situ ellipsometric study of surface immobilization of flagellar filaments

    NASA Astrophysics Data System (ADS)

    Kurunczi, S.; Németh, A.; Hülber, T.; Kozma, P.; Petrik, P.; Jankovics, H.; Sebestyén, A.; Vonderviszt, F.; Fried, M.; Bársony, I.

    2010-10-01

    Protein filaments composed of thousands of subunits are promising candidates as sensing elements in biosensors. In this work in situ spectroscopic ellipsometry is applied to monitor the surface immobilization of flagellar filaments. This study is the first step towards the development of layers of filamentous receptors for sensor applications. Surface activation is performed using silanization and a subsequent glutaraldehyde crosslinking. Structure of the flagellar filament layers immobilized on activated and non-activated Si wafer substrates is determined using a two-layer effective medium model that accounted for the vertical density distribution of flagellar filaments with lengths of 300-1500 nm bound to the surface. The formation of the first interface layer can be explained by the multipoint covalent attachment of the filaments, while the second layer is mainly composed of tail pinned filaments floating upwards with the free parts. As confirmed by atomic force microscopy, covalent immobilization resulted in an increased surface density compared to absorption.

  8. Study on algae removal by immobilized biosystem on sponge

    NASA Astrophysics Data System (ADS)

    Pei, Haiyan; Hu, Wenrong

    2006-10-01

    In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5h, the removal rates of algae, microcystins and UV260 were 90%, 94.17% and 84%, respectively. The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

  9. Effects of the immobilization supports on the catalytic properties of immobilized mushroom tyrosinase: a comparative study using several substrates.

    PubMed

    Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Cánovas, Francisco; García-Ruiz, Pedro Antonio

    2007-09-30

    Mushroom tyrosinase was immobilized from an extract onto glass beads covered with one of the following compounds: the crosslinked totally cinnamoylated derivatives of glycerine, D-sorbitol, D-manitol, 1,2-O-isopropylidene-alpha-D-glucofuranose, D-glucuronic acid, D-gulonic acid, sucrose, D-glucosone, D-arabinose, D-fructose, D-glucose, ethyl-D-glucopyranoside, inuline, dextrine, dextrane or starch, or the partially cinnamoylated derivative 3,5,6-tricinnamoyl-D-glucofuranose which was obtained by the acid hydrolysis of 1,2-O-isopropylidene-alpha-d-glucofuranose. The enzyme was immobilized by direct adsorption onto the support and the quantity of tyrosinase immobilized was found to increase with the hydrophobicity of the supports. The kinetic constants of immobilized tyrosinase acting on the substrates, 4-tert-butylcatechol, dopamine and DL-dopa, were studied. When immobilized tyrosinase acted on 4-tert-butylcatechol, the values of K(m)(app) were lower than these obtained for tyrosinase in solution while, when dopamine and DL-dopa were used, the K(m)(app) were higher. The order of the substrates as regards their ionizable groups, DL-dopa (two ionizable groups)>dopamine (one ionizable group)>4-tert-butylcatechol (no ionizable group) coincided with the order of the K(m)(app) values shown by tyrosinase immobilized on the hydrophobic supports, and was the inverse of that observed for tyrosinase in solution. The K(m)(app) values of immobilized tyrosinase were in all cases higher than those of soluble tyrosinase and depended on the nature of the support and the hydrophobicity of the substrate, meaning that it is possible to design supports with different degrees of selectivity towards a mixture of enzyme substrates in the reaction medium.

  10. Studies on the thermal inactivation of immobilized enzymes

    SciTech Connect

    Ulbrich, R.; Schellenberger, A.; Damerau, W.

    1986-04-01

    The thermal inactivation of a great number of immobilized enzymes shows a biphasic kinetics, which distinctly differs from the first-order inactivation kinetics of the corresponding soluble enzymes. As shown for ..cap alpha..-amylase, chymotrypsin, and trypsin covalently bound to silica, polystyrene, or polyacrylamide, the dependence of the remaining activities on the heating time can be well described by the sum of two exponential terms. To interpret this mathematical model function, the catalytic properties of immobilized enzymes (number of active sites in silica-bound trypsin, Km and Ea values in silica-bound ..cap alpha..-amylase and chymotrypsin) at different stages of inactivation and the influence of various factors (coupling conditions, addition of denaturants or stabilizers, etc.) on the thermal inactivation of silica-bound ..cap alpha..-amylase were studied. Furthermore, conformational alterations in the thermal denaturation of spin-labeled soluble and silica-bound ..beta..-amylase were compared by electron spin resonance (ESR) studies. The results suggest that the biphasic inactivation kinetics reflects two different pathways according to which catalytically identical enzyme molecules are predominantly inactivated. 45 references.

  11. Adhesion Peptide Immobilization on Electrospun Polymers: a Photoelectron Spectroscopy Study

    SciTech Connect

    Iucci, G.; Polzonetti, G.; Ghezzo, F.; Modesti, M.; Roso, M.; Dettin, M.

    2010-06-02

    The immobilization of an oligopeptide, mimicking the adhesion sequence of fibronectin, on the surface of polymer films prepared by electrospinning was investigated by XPS spectroscopy. Films of polycaprolactone (PCL) and poly(l-lactide-caprolactone)[P(LLA-CL)] were prepared by electrospinning onto aluminium substrates. A modified adhesion peptide containing a photoreactive group was immobilized on the surface of the polymer nanofibers by incubation in peptide solution and subsequent UV irradiation. XPS analysis yield evidence of successful peptide immobilization on the polymer surface; the amount of immobilized peptide increases with the concentration of the mother solution.

  12. Comperative study of catalase immobilization on chitosan, magnetic chitosan and chitosan-clay composite beads.

    PubMed

    Başak, Esra; Aydemir, Tülin; Dinçer, Ayşe; Becerik, Seda Çınar

    2013-12-01

    Catalase was immobilized on chitosan and modified chitosan. Studies were carried out on free-immobilized catalase concerning the determination of optimum temperature, pH, thermal, storage stability, reusability, and kinetic parameters. Optimum temperature and pH for free catalase and catalase immobilized were found as 35°C and 7.0, respectively. After 100 times of repeated tests, the immobilized catalases on chitosan-clay and magnetic chitosan maintain over 50% and 60% of the original activity, respectively. The ease of catalase immobilization on low-cost matrices and good stability upon immobilization in the present study make it a suitable product for further use in the food industry.

  13. [The study of photochemical immobilization of urease on polyether sulfone film surface].

    PubMed

    Li, Sai; Fu, Hao; Luo, Xianglin; Wan, Changxiu; Zhong, Yinping

    2002-01-01

    A new method of using photoactivable ester with azido group was described to immobilize urease on polyether sulfone(PES) film surface. The effects of photoactive enzyme concentration, temperature, pH, irradiation time on the activity of immobilized urease were investigated. Reused times and storage stability were also studied. The results showed that the surface concentration of urease immobilized on PES surface was about 0.33 mg/cm2. When the irradiation time was 5 minutes, the relative activity of immobilized urease was the highest and the activity increased with the increase of the concentration of photoactive urease solution. The optimum pH and temperature of immobilized urease were 7 and 50 degrees C respectively. The relative activity of immobilized urease was stable (50%) after 12 times reused at 50 degrees C.

  14. [Study of enzyme immunosensor immobilized by regenerated silk fibroin].

    PubMed

    Li, W; Li, Y R; Pan, N

    2001-11-01

    The author studies the enzyme immunosensor made up of graphite electrode and protein film of regenerated silk fibroin which is employed to immobilized antigen (rabbit IgG). IgG will be recognized and combined by antibody (goat-anti-rabbit IgG-HRP). After enlarging the signal of the combination of antigen and antibody by H2O2, the concentration of IgG is able to be measured by testing the electrode potential directly. The Enzyme Immunosensor is sensitive when measuring IgG and the detection limit of 1.2 x 10(-10) mol/L is found. It shows linear response over the concentration range of 4.1 x 10(-7)-1.2 x 10(-10) mol/L. Electrophoresis cuts down the time of antibody-antigen interaction from 90 min to 30 min. The response time is 15 s. Enzyme immunosensor with better stability and higher sensitivity can be used extensively in clinical diagnosis, medical and environmental studies, HLA molecular diagnosis and so on.

  15. Dual growth factor-immobilized microspheres for tissue reinnervation: in vitro and preliminary in vivo studies.

    PubMed

    Kim, Tae Ho; Oh, Se Heang; An, Dan Bi; Lee, Ji Youl; Lee, Jin Ho

    2015-01-01

    Growth factors (GFs) (basic fibroblast growth factor (bFGF) and/or nerve growth factor (NGF))-immobilized polycaprolactone (PCL)/Pluronic F127 microspheres were prepared using an isolated particulate-melting method and the sequential binding of heparin and GFs onto the microspheres. The GFs immobilized on the microspheres were released in a sustained manner over 28 days, regardless of GF type. From the in vitro culture of muscle-derived stem cells, it was observed that the NGF-immobilized microspheres induced more neurogenic differentiation than the bFGF-immobilized microspheres, as evidenced by a quantitative real-time polymerase chain reaction using specific neurogenic markers (Nestin, GFAP, β-tubulin, and MAP2) and Western blot (Nestin and β-tubulin) analyses. The dual bFGF/NGF-immobilized microspheres showed better neurogenic differentiation than the microspheres immobilized with single bFGF or NGF. From the preliminary animal study, the dual bFGF/NGF-immobilized microsphere group also showed effective nerve regeneration, as evaluated by immunocytochemistry using a marker - β-tubulin. The dual bFGF/NGF-immobilized PCL/Pluronic F127 microspheres may be a promising candidate for nerve regeneration in certain target tissues (i.e. muscles) leading to sufficient reinnervation.

  16. Immobilized E. coli alkaline phosphatase. Its properties, stability, and utility in studying the dephosphorylation of proteins.

    PubMed

    Basheeruddin, K; Rothman, V; Margolis, S

    1985-04-01

    We have immobilized E. coli alkaline phosphatase (EC 3.1.3.1) by linking it covalently to sepharose 4B. This preparation has several advantages over the soluble enzyme. The immobilized enzyme is easily separable from other constituents in incubation mixtures. The immobilized enzyme can be reused repeatedly and is more stable than the soluble enzyme to heat treatment in the presence of 10 mM Mg2+. The insoluble and soluble phosphatases removed 75 and 77%, respectively, of the inorganic phosphorus from casein. The immobilized enzyme inactivated two enzymes believed to be active in the phosphorylated state, acyl-CoA:cholesterol acyltransferase (ACAT) by 39% and NADPH-cytochrome P-450 reductase by 89%. The utility of immobilized alkaline phosphatase for studying the phosphorylation and dephosphorylation of soluble or membrane-bound enzymes and proteins is discussed.

  17. Immobilization of tryptophan hydroxylase by immune adsorption: a method to study regulation of catalytic activity.

    PubMed

    Johansen, P A; Jennings, I; Cotton, R G; Kuhn, D M

    1992-12-01

    Tryptophan hydroxylase (TPH) can be immobilized by adsorption to Pansorbin after binding to the monoclonal antibody PH8. This method yields recoveries of 35%-40% of total TPH activity in crude extracts and can be completed in 1.5 h. The immobilized form of TPH retains the essential kinetic properties of the native enzyme and responds to activators (phosphatidylserine) and inhibitors (catechol compounds) as does the native enzyme. Unlike TPH in brain extracts, immobilized TPH is not activated by calcium-stimulated phosphorylating conditions. When extracts from which TPH has been precipitated, and which contain calcium-calmodulin dependent protein kinase are added to immobilized TPH, the activation of TPH is restored. This method of immobilization of TPH via immune-adsorption allows for the highly specific and rapid preparation of affinity purified TPH that can be used to study the regulation of this enzyme by a variety of effectors, especially protein kinases.

  18. Effects of postoperative immobilization on the reconstructed anterior cruciate ligament. An experimental study in rabbits.

    PubMed

    Muneta, T; Yamamoto, H; Takakuda, K; Sakai, H; Furuya, K

    1993-01-01

    To investigate the effects of postoperative immobilization and limited motion on reconstructed anterior cruciate ligaments, 28 rabbits received an anterior cruciate ligament reconstruction using autogenous Achilles tendon and were then divided into three groups: fully immobilized, 4 weeks immobilized, and limited motion. Two rabbits from each group were evaluated macroscopically, histologically and microangiographically at 4-week intervals until 12 weeks postoperatively. An additional six rabbits in the 4 weeks immobilized and limited motion groups were studied biomechanically at 12 weeks postoperatively. Macroscopically, both immobilized groups showed more proliferation of the infrapatellar fat pad, which was adherent to the reconstructed anterior cruciate ligament. Histology revealed more rapid regeneration of reconstructed anterior cruciate ligaments in the limited motion group, with no findings of necrosis in the mid-substance. Microangiography indicated faster normalization of vascularity in the limited motion group. The biomechanical study showed no significant difference in laxity between the 4 weeks immobilized and limited motion groups. The graft stiffness and maximum load to failure were greater for the limited motion group, although the increase was not statistically significant. The histologic and microangiographic results from the limited number of animals in this study support limited postoperative motion in the anterior cruciate ligament reconstructed knee. However, there were no differences in terms of the biomechanical parameters at 12 weeks postoperatively between the immobilized and limited motion treatment modes.

  19. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    SciTech Connect

    Stanger, Keith James

    2003-01-01

    The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-α-acetamidocinnamate (MAC), has the illustrated structure as established by 31P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]4, [Rh(COD)2]+BF4-, [Rh(COD)Cl]2, and RhCl3• 3H2O, adsorbed on SiO2 are optimally activated for toluene hydrogenation by pretreatment with H2 at 200 C. The same complexes on Pd-SiO2 are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH2)3s-]Re(O)(Me)(PPh3) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.

  20. Silica-Immobilized Enzyme Reactors; Application to Cholinesterase-Inhibition Studies

    DTIC Science & Technology

    2006-03-01

    AFRL-ML-TY-TP-2006-4575 PREPRINT SILICA-IMMOBILIZED ENZYME REACTORS; APPLICATON TO CHOLINESTERASE- INHIBITION STUDIES Heather R...P K 1 g i ( u a i a i e v b c a m p l 1 d Journal of Chromatography B, 843 (2006) 310–316 Silica-immobilized enzyme reactors; application to...method is reported for the preparation of an immobilized enzyme reactor (IMER) using silica-encapsulated equine utyrylcholinesterase (BuChE) as a model

  1. Comparative study of random and oriented antibody immobilization techniques on the binding capacity of immunosensor.

    PubMed

    Kausaite-Minkstimiene, A; Ramanaviciene, A; Kirlyte, J; Ramanavicius, A

    2010-08-01

    A comparative study of four different antibody immobilization techniques that are suitable for modification of surface plasmon resonance (SPR) chip (SPR-chip) is reported. Antibodies against human growth hormone (anti-HGH) were used as the model system. The evaluated SPR-chip modification techniques were (i) random immobilization of intact anti-HGH (intact-anti-HGH) via self-assembled monolayer (SAM) based on 11-mercaptoundecanoic acid (MUA); (ii) random immobilization of intact-anti-HGH within carboxymethyl dextran (CMD) hydrogel by direct covalent amine coupling technique; (iii) oriented coupling of intact-anti-HGH via Fc-fragment to protein-G layer assembled on SAM consisting of MUA (MUA/pG); (iv) oriented immobilization of fragmented anti-HGH antibodies (frag-anti-HGH) via their native thiol-groups directly coupled to the gold. To liberate these thiol groups, the intact-anti-HGH was chemically "divided" into two frag-anti-HGH fragments by chemical reduction with 2-mercaptoethylamine (2-MEA). Optimal concentration of 2-MEA for preparation of anti-HGH was 15 mM. The surface concentration of immobilized antibodies and the antigen binding capacity for all four differently modified SPR-chips was evaluated and compared. The maximum surface concentration of immobilized intact-anti-HGH was obtained by immobilizing the antibody within CMD-hydrogel. The maximal antigen binding capacity was obtained by SPR-chip based on intact-anti-HGH immobilized via MUA/pG. The immobilization based on application of frag-anti-HGH was found to be the most suitable for design of SPR-immunosensor for HGH detection, due to its sufficient antigen binding capacity, simplicity, and low cost in respect to the currently evaluated techniques.

  2. Enzyme-immobilized reactors for rapid and efficient sample preparation in MS-based proteomic studies.

    PubMed

    Yamaguchi, Hiroshi; Miyazaki, Masaya

    2013-02-01

    Proteolysis is a key step in proteomic studies integrated with MS analysis but the conventional method of in-solution digestion is limited by time-consuming procedures and low sensitivity. Furthermore, obtaining reliable peptide maps and meaningful sequence data using MS analysis requires not only the separation of the digested peptides but also strictly defined proteolysis conditions. Recently, various immobilized-enzyme reactors have been developed for highly efficient proteolysis in MS-based proteomic analysis. This review focuses on the proteolysis step using protease-immobilized reactors and rapid analysis of protein sequences. We describe the preparation of enzyme reactors by several techniques and protein digestion under unusual conditions. Analysis of posttranslational modifications by enzyme reactors prepared using our immobilization method is presented as a model application. Analysis systems using immobilized-enzyme reactors are expected to become useful tools for proteomic studies and diverse applications in biotechnology.

  3. Functionalized graphene sheets as immobilization matrix for Fenugreek β-amylase: enzyme kinetics and stability studies.

    PubMed

    Srivastava, Garima; Singh, Kritika; Talat, Mahe; Srivastava, Onkar Nath; Kayastha, Arvind M

    2014-01-01

    β-Amylase finds application in food and pharmaceutical industries. Functionalized graphene sheets were customised as a matrix for covalent immobilization of Fenugreek β-amylase using glutaraldehyde as a cross-linker. The factors affecting the process were optimized using Response Surface Methodology based Box-Behnken design of experiment which resulted in 84% immobilization efficiency. Scanning and Transmission Electron Microscopy (SEM, TEM) and Fourier Tansform Infrared (FTIR) spectroscopy were employed for the purpose of characterization of attachment of enzyme on the graphene. The enzyme kinetic studies were carried out for obtaining best catalytic performance and enhanced reusability. Optimum temperature remained unchanged, whereas optimum pH showed shift towards acidic range for immobilized enzyme. Increase in thermal stability of immobilized enzyme and non-toxic nature of functionalized graphene can be exploited for production of maltose in food and pharmaceutical industries.

  4. Spectroscopy study of Zn, Cd, Pb and Cr ions immobilization on C-S-H phase.

    PubMed

    Żak, Renata; Deja, Jan

    2015-01-05

    Calcium silicate hydrates (C-S-H) have a large number of structural sites available for cations and anions to bind. The C-S-H phases are materials which have ability to toxic ions immobilization. Immobilization mechanisms for C-S-H include sorption, phase mixing, substitution and precipitation of insoluble compounds. This study presents the C-S-H (prepared with C/S ratios 1.0) phase as absorbent for immobilization of Zn, Cd, Pb and Cr ions. The C-S-H spectra before and after incorporation of heavy metals ions into the C-S-H structure were obtained. The effect of added heavy metals ions on the hydration phenomena was studied by means of X-ray diffractions analysis. FTIR spectra was measured. The microstructure and phase composition of C-S-H indicate that they can play an essential role in the immobilization of heavy metals. The properties of C-S-H in the presence of Zn, Cd, Pb and Cr cations were studied. The leaching ML test was used to evaluate the level of immobilization of heavy metals in C-S-H. The leached solutions are diluted and analyzed using atomic absorption spectrometry (AAS) and the activated solid particles are separated, washed, desiccated and analyzed by Fourier transform infrared (FTIR) spectroscopy. It was found that the degree of Cd, Zn, Pb and Cr cations immobilization was very high (exceeding 99.96%).

  5. Immobilized low-level waste disposal options configuration study

    SciTech Connect

    Mitchell, D.E.

    1995-02-01

    This report compiles information that supports the eventual conceptual and definitive design of a disposal facility for immobilized low-level waste. The report includes the results of a joint Westinghouse/Fluor Daniel Inc. evaluation of trade-offs for glass manufacturing and product (waste form) disposal. Though recommendations for the preferred manufacturing and disposal option for low-level waste are outside the scope of this document, relative ranking as applied to facility complexity, safety, remote operation concepts and ease of retrieval are addressed.

  6. Kinetic study of Candida antarctica lipase B immobilization using poly(methyl methacrylate) nanoparticles obtained by miniemulsion polymerization as support.

    PubMed

    Valério, Alexsandra; Nicoletti, Gabrieli; Cipolatti, Eliane P; Ninow, Jorge L; Araújo, Pedro H H; Sayer, Cláudia; de Oliveira, Débora

    2015-03-01

    With the objective to obtain immobilized Candida antarctica lipase B (CalB) with good activity and improved utilization rate, this study evaluated the influence of enzyme and crodamol concentrations and initiator type on the CalB enzyme immobilization in nanoparticles consisting of poly(methyl methacrylate) (PMMA) obtained by miniemulsion polymerization. The kinetic study of immobilized CalB enzyme in PMMA nanoparticles was evaluated in terms of monomer conversion, particle size, zeta potential, and relative activity. The optimum immobilization condition for CalB was compared with free enzyme in the p-NPL hydrolysis activity measurement. Results showed a higher CalB enzyme stability after 20 hydrolysis cycles compared with free CalB enzyme; in particular, the relative immobilized enzyme activity was maintained up to 40%. In conclusion, PMMA nanoparticles proved to be a good support for the CalB enzyme immobilization and may be used as a feasible alternative catalyst in industrial processes.

  7. Studies on improving the immobilized bead reusability and alkaline protease production by isolated immobilized Bacillus circulans (MTCC 6811) using overall evaluation criteria.

    PubMed

    Subba Rao, Ch; Madhavendra, S S; Sreenivas Rao, R; Hobbs, Phil J; Prakasham, R S

    2008-07-01

    This study uses an overall evaluation criterion for improving the immobilized bead reusability and extracellular enzyme production by immobilized cells by assigning relative weightage to bead reusability, enzyme production, and cell leakage. Initially, alkaline protease production by alginate-immobilized Bacillus circulans (MTCC 6811) was analyzed using L18 orthogonal array (OA). The resultant optimized parameters were further fine-tuned with L9 OA experimentation. At L18-OA analysis, inoculum level and CaCl(2) had least influence at individual level. At the interactive level, incubation time revealed maximum and minimum interaction with sodium alginate and glucose concentration, respectively. L9 experimentation indicated that glucose concentration contributed the major influence on protease production followed by matrix material and incubation time at the individual level, and at the interactive level, matrix concentration played a vital role by interacting with incubation time, inoculum, and CaCl(2) concentration. All selected input parameters showed significance either at individual level or interactive in both OAs. Scanning electron microscopy analysis showed bacterial morphology variation with variation of matrix concentration. Overall, glucose concentration depicted a major influence at the individual level for the enzyme production. Significant improvement, approximately 147%, in enzyme yield was observed. Economic enzyme production by immobilized B. circulans is regulated by interactive influence of fermentation parameters, which influence the immobilized bead stability, reusability, and enzyme yield.

  8. Comparison between Free and Immobilized Ion Effects on Hydrophobic Interactions: A Molecular Dynamics Study.

    PubMed

    Huang, Kai; Gast, Sebastian; Ma, C Derek; Abbott, Nicholas L; Szlufarska, Izabela

    2015-10-15

    Fundamental studies of the effect of specific ions on hydrophobic interactions are driven by the need to understand phenomena such as hydrophobically driven self-assembly or protein folding. Using β-peptide-inspired nanorods, we investigate the effects of both free ions (dissolved salts) and proximally immobilized ions on hydrophobic interactions. We find that the free ion effect is correlated with the water density fluctuation near a nonpolar molecular surface, showing that such fluctuation can be an indicator of hydrophobic interactions in the case of solution additives. In the case of immobilized ion, our results demonstrate that hydrophobic interactions can be switched on and off by choosing different spatial arrangements of proximal ions on a nanorod. For globally amphiphilic nanorods, we find that the magnitude of the interaction can be further tuned using proximal ions with varying ionic sizes. In general, univalent proximal anions are found to weaken hydrophobic interactions. This is in contrast to the effect of free ions, which according to our simulations strengthen hydrophobic interactions. In addition, immobilized anions of increasing ionic size do not follow the same ordering (Hofmeister-like ranking) as free ions when it comes to their impact on hydrophobic interactions. The immobilized ion effect is not simply correlated with the water density fluctuation near the nonpolar side of the amphiphilic nanorod. We propose a molecular picture that explains the contrasting effects of immobilized versus free ions.

  9. Laccase production by free and immobilized mycelia of Peniophora cinerea and Trametes versicolor: a comparative study.

    PubMed

    Silvério, Sara C; Moreira, Sérgio; Milagres, Adriane M F; Macedo, Eugénia A; Teixeira, José A; Mussatto, Solange I

    2013-03-01

    The production of laccase by immobilized mycelia of Peniophora cinerea and Trametes versicolor was studied. In an initial stage, experimental assays were performed in Erlenmeyer flasks using free and immobilized mycelium, and the performance of the fungal strains to produce the enzyme was compared. Both fungi adhered into the support material (a synthetic fiber), growing not only on the surface but also in the interspaces of the fibers. Immobilization of P. cinerea provided a 35-fold increase in laccase production when compared to the production obtained by using free mycelium. On the other hand, immobilization of T. versicolor caused a decrease in laccase activity. A comparison between the strains revealed that immobilized P. cinerea (3,500 U/L) surpassed the enzyme production by free T. versicolor (800 U/L). When the conditions that gave the best laccase production to each fungus were employed in a stirred tank bioreactor, very low laccase production was observed for both the cases, suggesting that shear stress and mycelia damage caused by the agitation impellers negatively affected the enzyme production.

  10. [Methods of microorganism immobilization for dynamic atomic-force studies (review)].

    PubMed

    Kuiukina, M S; Korshunova, I O; Rubtsova, E V; Ivshina, I B

    2014-01-01

    Atomic-force microscopy (AFM) is an efficient method for studying the surface ultrastructure and nanomechanical properties of biological objects (including microorganisms). A correctly selected method of microorganism immobilization (that provides a strong attachment of cells on the surface of a biologically inert substrate and the preservation of their native properties) is an important condition of AFM scanning in a liquid medium. Comparative characteristics of methods of microorganism immobilization (that are applied in dynamic AFM studies) are given in the review. Technologies of mechanical retention and chemical binding of cells to a substrate, as well as protein and immunospecific adsorption, are considered.

  11. Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies

    NASA Astrophysics Data System (ADS)

    Docters, E. H.; Smolko, E. E.; Suarez, C. E.

    The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

  12. Flow-through immobilized enzyme reactors based on monoliths: II. Kinetics study and application.

    PubMed

    Vlakh, Evgenia G; Tennikova, Tatiana B

    2013-03-01

    In the last decade, the application of monolithic materials has rapidly expanded to the realization of flow-through bioconversion processes. Up to these days, different classes of enzymes such as hydrolases, lyases, and oxidoreductases have been immobilized on organic, inorganic, or hybrid monolithic materials to prepare the effective flow-through enzymes reactors for application in proteomics, biotechnology, pharmaceutics, organic synthesis, and biosensoring. Current review describes the results of kinetic study and specialties of flow-through immobilized enzyme reactors based on the existing monolithic materials.

  13. Comparative study of 6-APA production by free and agar immobilized bacteria in nutrient broth culture.

    PubMed

    Dolui, A K; Das, S

    2011-04-01

    In the present study different bacterial samples were isolated from soil of different places of Dibrugarh and screened for biotransformation ability to produce 6-Aminopenicillanic acid. Among ten isolated bacterial samples, three gram positive bacterial samples designated as AKDD-2, AKDD-4 and AKDD-6 showed the production of 6-APA from penicillin G. Assessment of production of 6-APA after incubation in penicillin G (2 mg/ml) by three different samples separately in free and agar immobilization state was done by HPLC analysis. Reusability of immobilized cells was found successful up to 14 days.

  14. Study of bone mineral metabolism. [during body immobilization, bed rest, and space flight

    NASA Technical Reports Server (NTRS)

    Palmer, H. E.

    1975-01-01

    The use of Sr-85 as an indicator of the skeletal location and relative amount of bone demineralization which occurs during immobilization of the body or body parts, bed-rest or space flight was studied. The bone mineral replacement which occurs after immobilization was measured rather than the bone loss which occurs during immobilization. In a study with two adult beagle dogs, the Sr-85 uptake in a leg which had been immobilized for two months was 400 percent higher than the uptake in the legs in regular use. This increased uptake probably resulted from only a few percent loss in bone mineral and indicates that losses less than one percent can be easily detected and located. The sensitivity, simplicity, and low radiation dose associated with the use of this method indicates that it should receive consideration for use on humans in bed-rest and space flight studies. Methods for measuring changes in total body nitrogen and in assisting the Johnson Space Center in calibrating a whole body counter for total body potassium measurements were also investigated.

  15. Mechanistic study for immobilization of cysteine-labeled oligopeptides on UV-activated surfaces.

    PubMed

    Ong, Lian Hao; Ding, Xiaokang; Yang, Kun-Lin

    2014-10-01

    In this study, we report immobilization of cysteine-labeled oligopeptides on UV activated surfaces decorated with N,N-dimethyl-n-octadecyl-3-aminopropyltrimethoxysilyl chloride (DMOAP). Our result shows that cysteine group, regardless of its position in the oligopeptide, is essential for successful immobilization of oligopeptide on the UV-activated surface. A possible reaction mechanism is nucleophilic addition of thiolates to surface aldehyde groups generated during UV activation. By using this technique, we are able to incorporate anchoring points into oligopeptides through cysteine residues. Furthermore, immobilized oligopeptides on the UV-activated surface is very stable even under harsh washing conditions. Finally, we show that an HPQ-containing oligopeptide can be immobilized on the UV-activated surface, but the final surface density and its ability to bind streptavidin are affected by the position of cysteine and HPQ. An oligopeptide with a cysteine at the N-terminus and a HPQ motif at the C-terminus gives the highest binding signal in the streptavidin-binding assay. This result is potentially useful for the development of functional oligopeptide microarrays for detecting target protein molecules.

  16. [Study on immobilized cells for producing alpha-amylase by using polyving alcohol as the carrier(II): The effect of fermentating conditions on the ability producing alpha-amylase of the cells immobilized with polyving alcohol as the corrier and continuous fermentation of the immobilized cells in CSTR].

    PubMed

    Liu, Z; Wang, J; Li, Z

    1998-03-01

    The effects of fermentating conditions on the ability of immobilized cells with PVA as carrier for producing alpha-amylase were studied. The continuous fermentation with the immobilized cells were tested in continuous flow stirred tank reactor (CSTR). The results showed that the adaptability of the immobilized Bacillus substilis to pH increased after immobilization. In CSTR, the immobilized cells can be fermentated continuously for 360 hrs and the activity of alpha-amylase can be kept on the level of about 170 u/ml.

  17. Kinetic modeling and docking study of immobilized lipase catalyzed synthesis of furfuryl acetate.

    PubMed

    Mathpati, Ashwini C; Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2016-03-01

    The present work deals with the kinetic modeling and docking study for the furfuryl acetate synthesis using immobilized Burkholderia cepacia (BCL) lipase. Initially various lipases were immobilized on hydroxypropyl methyl cellulose (HPMC) and poly vinyl alcohol (PVA) base hybrid polymer matrix. After screening of various immobilized biocatalysts, HPMC:PVA:BCL was found to be a robust biocatalyst. Various reaction conditions were optimized using response surface methodology (RSM) based on a four-factor-three-level Box-Behnken design. The optimal conditions were obtained at molar ratio of 1:2 of furfuryl alcohol to acyl donor, temperature 50°C with catalyst loading of 30mg in 3mL of non-aqueous media toluene. Under these conditions 99.98% yield was obtained in 3h. The Arrhenius plot showed that the activation energy for furfuryl acetate synthesis was 10.68kcal/mol. The kinetics of reaction was studied close to optimized conditions which obey order bi-bi model. Molecular docking study was carried out to understand the active site of BCL which is responsible for the reaction. It was observed that the reaction proceeds via acylation of the active serine of BCL and demonstrating strong hydrogen bond between the substrate and histidine site. The catalyst recyclability study was carried up to five cycles.

  18. Covalent Immobilization of Biotin on Magnetic Nanoparticles: Synthesis, Characterization, and Cytotoxicity Studies.

    PubMed

    Islam, Md Rafiqul; Bach, Long Giang; Vo, Thanh-Sang; Lim, Kwon Taek

    2015-01-01

    A simple protocol for covalent immobilization of biotin onto the surface of Fe3O4 magnetic nanoparticles (MNPs) for improving the biocompatibility of original MNPs has been realized. MNPs were first prepared by co-precipitation method which was subsequently anchored with functionalized biotin. The as-synthesized MNPs were observed to be monocrystalline as evidenced from XRD and TEM images. The covalent grafting of biotin to MNPs was confirmed by FT-IR. The XPS analysis suggested the successful preparation of Biotin-f-MNPs. The as-synthesized Biotin-f-MNPs were found to be superparamagnetic character as recorded by SQUID. Cell viability studies revealed that the biocompatibility of MNPs was improved upon Biotin immobilization.

  19. Electrochemical study of gelatin as a matrix for the immobilization of horse heart cytochrome c.

    PubMed

    De Wael, Karolien; De Belder, Stijn; Van Vlierberghe, Sandra; Van Steenberge, Geert; Dubruel, Peter; Adriaens, Annemie

    2010-10-15

    The aim of this paper is to emphasize the strength of gelatin as a stable matrix for redox enzymes. Cyclic voltammetry has been applied for a detailed electrochemical study of horse heart cytochrome c (HHC) entrapped in a gelatin matrix immobilized on a gold electrode. The influence of the HHC concentration, the mass percentage of the gelatin and the nature of the gelatin on the electrochemical behaviour of HHC have been described in detail. In addition, attenuated total reflection infrared (ATR-IR) spectroscopy was used to prove the immobilization on a qualitative and conformational level. The thickness of the gelatin film was determined using a non-contact optical profiler. These results open up new perspectives in the development of stable, biocompatible matrices for redox enzymes. The latter has its relevance in the field of biosensor development.

  20. Hydrated lime for metals immobilization and explosives transformation: Treatability study.

    PubMed

    Martin, W Andy; Larson, S L; Nestler, C C; Fabian, G; O'Connor, G; Felt, D R

    2012-05-15

    Fragmentation grenades contain Composition B (RDX and TNT) within a steel shell casing. There is the potential for off-site migration of high explosives and metals from hand grenade training ranges by transport in surface water and subsurface transport in leachate. This treatability study used bench-scale columns and mesocosm-scale laboratory lysimeters to investigate the potential of hydrated lime as a soil amendment for in situ remediation of explosives and metals stabilization in hand grenade range soils. Compared to the unamended soil there was a 26-92% reduction of RDX in the leachate and runoff water from the lime treated soils and a 66-83% reduction of zinc in the leachate and runoff water samples; where the hand grenade range metals of concern were zinc, iron, and manganese. The amended soil was maintained at the target pH of greater than 10.5 for optimum explosives decomposition. The treatability study indicated a high potential of success for scale-up to an in situ field study.

  1. Advantages of using non-isothermal bioreactors in agricultural waste water treatment by means of immobilized urease. Study on the influence of spacer length and immobilization method.

    PubMed

    El Sherif, Hazem; Di Martino, Silvana; Travascio, Paola; De Maio, Anna; Portaccio, Marianna; Durante, Daniela; Rossi, Sergio; Canciglia, Paolo; Mita, Damiano G

    2002-05-08

    The behavior of three different catalytic membranes, obtained by immobilizing urease on nylon sheets chemically grafted with methyl methacrylate, was studied in a bioreactor operating under isothermal and non-isothermal conditions. Membrane activation was carried out by condensation or acyl azide reaction, and spacers of different lengths, such as hexamethylendiamine or hydrazine, were used. Under isothermal conditions, the activities of the catalytic membranes and soluble urease were characterized as a function of pH, temperature, and urea concentration. Both enzyme forms showed the same optimum pH, whereas the optimum temperature was lower for the immobilized enzymes. The spacer length appeared to determine broader pH- and temperature-activity profiles for the urease derivatives. The apparent K(m) values of the insoluble urease were dependent on membrane type and were higher than those of the soluble counterpart, thus indicating an affinity loss for urea. Under non-isothermal conditions, all membranes exhibited an increase of percentage activity proportional to the applied temperature difference and decreasing with the increase of urea concentrations. A decrease of the apparent K(m) was also observed. These results suggest that substrate diffusion limitations due to the immobilization process can be overcome in the presence of temperature gradients. In addition, the remarkable reduction of the production times supports the use of non-isothermal bioreactors for the treatment of urea-polluted waste waters.

  2. Glyphosate degradation by immobilized bacteria: laboratory studies showing feasibility for glyphosate removal from waste water.

    PubMed

    Heitkamp, M A; Adams, W J; Hallas, L E

    1992-09-01

    To evaluate immobilized bacteria technology for the removal of low levels of glyphosate (N-phosphonomethylglycine) from aqueous industrial effluents, microorganisms with glyphosate-degrading activity obtained from a fill and draw enrichment reactor inoculated with activated sludge were first exposed to glyphosate production wastes containing 500-2000 mg glyphosate/L. The microorganisms were then immobilized by adsorption onto a diatomaceous earth biocarrier contained in upflow Plexiglas columns. The columns were aerated, maintained at pH 7.0-8.0, incubated at 25 degrees C, supplemented with NH4NO3 (50 mg/L), and exposed to glyphosate process wastes pumped upflow through the biocarrier. Glyphosate degradation to aminomethylphosphonic acid was initially > 96% for 21 days of operation at flows yielding hydraulic residence times (HRTs) as short as 42 min. Higher flow rate studies showed > 98% removal of 50 mg glyphosate/L from the waste stream could be achieved at a HRT of 23 min. Glyphosate removal of > 99% at a 37-min HRT was achieved under similar conditions with a column inoculated with a pure culture of Pseudomonas sp. strain LBr, a bacterium known to have high glyphosate-degrading activity. After acid shocking (pH 2.8 for 18 h) of a column of immobilized bacteria, glyphosate-degrading activity was regained within 4 days without reinoculation. Although microbial growth and glyphosate degradation were not maintained under low organic nutrient conditions in the laboratory, the low levels of degradable carbon (45-94 mg/L) in the industrial effluent were sufficient to support prolonged glyphosate-degrading activity. The results demonstrated that immobilized bacteria technology is effective in removing low levels of glyphosate in high-volume liquid waste streams.

  3. [Study on influence between activated carbon property and immobilized biological activated carbon purification effect].

    PubMed

    Wang, Guang-zhi; Li, Wei-guang; He, Wen-jie; Han, Hong-da; Ding, Chi; Ma, Xiao-na; Qu, Yan-ming

    2006-10-01

    By means of immobilizing five kinds of activated carbon, we studied the influence between the chief activated carbon property items and immobilized bioactivated carbon (IBAC) purification effect with the correlation analysis. The result shows that the activated carbon property items which the correlation coefficient is up 0.7 include molasses, abrasion number, hardness, tannin, uniform coefficient, mean particle diameter and effective particle diameter; the activated carbon property items which the correlation coefficient is up 0.5 include pH, iodine, butane and tetrachloride. In succession, the partial correlation analysis shows that activated carbon property items mostly influencing on IBAC purification effect include molasses, hardness, abrasion number, uniform coefficient, mean particle diameter and effective particle diameter. The causation of these property items bringing influence on IBAC purification is that the activated carbon holes distribution (representative activated carbon property item is molasses) provides inhabitable location and adjust food for the dominance bacteria; the mechanical resist-crash property of activated carbon (representative activated carbon property items: abrasion number and hardness) have influence on the stability of biofilm; and the particle diameter size and distribution of activated carbon (representative activated carbon property items: uniform coefficient, mean particle diameter and effective particle diameter) can directly affect the force of water in IBAC filter bed, which brings influence on the dominance bacteria immobilizing on activated carbon.

  4. [Study of immobilization and properties of urease for creation of a biosensor based on semiconductor structures].

    PubMed

    Bubriak, O A; Khustochka, L N; Soldatkin, A P; Starodub, N F

    1992-01-01

    Many-sided investigations of urease immobilization methods were carried out to create the biosensor devices on the base of semiconductor structures. Special attention was concentrated on the biomembrane formation by means of urease and bovine serum albumin (BSA) cross-linking by gaseous glutaraldehyde. Optimal conditions for the formation process were selected which preserve about 20% of total urease activity after the cross-linking. The properties of enzyme immobilized by the above-mentioned method have been comprehensively studied. They included the urease activity dependence on pH, ionic strength, incubation buffer capacity as well as the enzyme stability during its functioning, storing and thermoinactivation. As was shown, for immobilized ureas Km value for urea at pH 7.0 and 20 degrees C is 1.65 time less than for free enzyme. In the presence of EDTA (1 mM) the enzyme activity in the biomembrane is practically unchanged under a month storing. Biomembrane possesses good adhesion to silicon surface and its swelling level under different conditions does not exceed 35%. The conclusion is made about the prospects of the used method of biomembrane formation for biosensor technology based on semiconductor structures.

  5. High pressure studies on hesperitin production with hesperidinase free and immobilized in calcium alginate beads

    NASA Astrophysics Data System (ADS)

    Furtado, Andreia; Rosário, Pedro M.; Calado, António R. T.; Alfaia, António J. I.; Ribeiro, Maria H. L.

    2012-03-01

    The use of high pressure for the enzymatic synthesis of pharmacologically interesting molecules is a very important tool. Hesperidin and hesperitin exhibit anti-inflammatory, antimicrobial, antioxidant, and anticarcinogenic properties and prevent bone loss. However, hesperidin has a low bioavailability compared with hesperitin, due to the rutinoside moiety attached to the flavonoid. The aim of this work was the enzymatic production of hesperitin from hesperidin (soluble and insoluble) with hesperidinase free and immobilized in Ca-alginate beads, under high pressure conditions. The work was focused on the optimization of enzyme activity, studying the effects: pressure (50-150 MPa), temperature (35-75 °C), concentration of substrate (100-800 mg/L), and immobilization of hesperidinase. An 18-fold increase in hesperidinase residual activity was observed under high pressure conditions of 100 MPa compared to 0.1 MPa. A higher specificity of the hydrolytic reaction under high pressure (100 MPa) with a two-and three-fold increase in the ratio K cat/K M (specificity constant) at 55 °C and 75 °C was observed. A two-fold increase in the maximum activity at 100 MPa was observed with immobilized hesperinase compared to 0.1 MPa. In the second reutilization, almost a four-fold increase was obtained under high pressure conditions in comparison to atmospheric pressure.

  6. Study of ionic liquid immobilization on polyvinyl ferrocene substrates for gas sensor arrays.

    PubMed

    Hou, Kuang-Yu; Rehman, Abdul; Zeng, Xiangqun

    2011-04-19

    In this report, the effects of conductive polymer oxidation states and structures on the design and development of ionic liquid (IL)/conductive polymer (CP) composite films for gas sensing are systematically characterized. Four different polyvinyl ferrocene (PVF) films synthesized by varying the conditioning potential (0.7 vs 0.0 V) and the electrolyte are tested for their gas-sensing properties (e.g., sensitivity, selectivity, response time, linearity, and dynamic range against various gas analytes such as dichloromethane, ethanol, natural gas, methane, formaldehyde (37%), and benzene) utilizing the quartz crystal microbalance (QCM) and ATR-FT-IR. The best available film is further studied as a substrate for the immobilization of various ILs that enhanced both the sensitivity and selectivity. Finally, two arrays, each comprising four sensors with the following scheme are developed and characterized for their ability to classify the four target analytes by using linear discriminant analysis: (1) the highest sensitivity PVF film immobilized with four different ILs and (2) the highest sensitivity IL immobilized in four different PVF films. Array 2 is proven to be much better than array 1 in discriminating the analytes, which is very significant in establishing the fact that a diverse set of PVF redox states allow the rational development of a PVF/IL composite-based sensor array in order to analyze complex mixtures utilizing structural differences and the extent of intermolecular interactions.

  7. Double-Barrier mechanism for chromium immobilization: A quantitative study of crystallization and leachability.

    PubMed

    Liao, Changzhong; Tang, Yuanyuan; Liu, Chengshuai; Shih, Kaimin; Li, Fangbai

    2016-07-05

    Glass-ceramics are well known for the excellent combination properties provided by their components, a glassy matrix and crystalline phases, and have promising applications in the immobilization and detoxification of solid waste containing toxic metals. Glass-ceramic products were successfully synthesized in CaO-MgO-SiO2-Al2O3 -Cr2O3 system. Two key measures--partitioning ratio of Cr in the spinel and Cr leaching ratio--were used to investigate the mechanism of Cr immobilization in the glass-ceramic products. The results of powder X-ray diffraction revealed that both spinel and diopside were major crystalline phases in the products. The value of x in the MgCr(x)Al(2-x)O4 spinel was highly related to the amount of Cr2O3 added to the glass-ceramic system. As Cr2O3 content increased, the proportion of spinel phase increased, while that of glass phase decreased. The partitioning ratio of Cr in spinel phase was about 70% for 2 wt.% Cr2O3, and increased to 90% when loaded with 10 wt.% of Cr2O3. According to the results of the prolonged toxicity characteristic leaching procedure, the Cr leaching ratio decreased with the increase of Cr partitioning ratio into the spinel phase. The findings of this study clearly indicate that glass-ceramic formed by spinel structure and residual glass successfully immobilized Cr.

  8. Determinants of bone mineral density in immobilization: a study on hemiplegic patients.

    PubMed

    del Puente, A; Pappone, N; Mandes, M G; Mantova, D; Scarpa, R; Oriente, P

    1996-01-01

    Osteoporosis that develops during immobilization is a severe condition that confers increased risk of fractures with their burden of mortality and disability. The aim of this study was to investigate the determinants of immobilization osteoporosis. As a model of this condition we studied hemiplegic subjects, measuring bone mineral density in the paralyzed lower limb as compared with the non-paralyzed one. In spite of the limits related to the loss of nervous stimulation, this model offers the advantage of a proper control for the complex genetic and environmental cofactors involved. We examined 48 hemiplegic subjects (31 men, 17 women in menopause) admitted consecutively over a 9-month period. Mean length immobilization was 10.9 months for men (range 1-48 months) and 7.8 months for women (range 1-40 months). The average time since menopause was 14.9 years (range 1.7-23.9 years). For each subject the following were performed: questionnaire, medical examination, anthropometric measurements, evaluation of the scores for spasticity and for lower limb motor capacity in order to account for the different degrees of disability among patients. Bone mineral density was measured using dual-energy X-ray absorptiometry (DXA) at both femoral necks. For each patient we defined a percentage difference in bone loss between the paralyzed and non-paralyzed limb. Regression coefficient were calculated by multiple logistic regression. There was significant bone loss in the paralyzed limb in both sexes, accounting for up to 6.3% in women. Multiple regression analysis showed that the degree of bone loss depends significantly and directly on the length of immobilization, even when controlling for age and sex in the regression model (R = 0.193, p = 0.034). However, when time since menopause was included in the regression model, with length of immobility as a covariate, it was the only significant determinant of bone loss (R = 0.312, p = 0.039). No additional factors were observed among

  9. Immobilized lysozyme for the continuous lysis of lactic bacteria in wine: Bench-scale fluidized-bed reactor study.

    PubMed

    Cappannella, Elena; Benucci, Ilaria; Lombardelli, Claudio; Liburdi, Katia; Bavaro, Teodora; Esti, Marco

    2016-11-01

    Lysozyme from hen egg white (HEWL) was covalently immobilized on spherical supports based on microbial chitosan in order to develop a system for the continuous, efficient and food-grade enzymatic lysis of lactic bacteria (Oenococcus oeni) in white and red wine. The objective is to limit the sulfur dioxide dosage required to control malolactic fermentation, via a cell concentration typical during this process. The immobilization procedure was optimized in batch mode, evaluating the enzyme loading, the specific activity, and the kinetic parameters in model wine. Subsequently, a bench-scale fluidized-bed reactor was developed, applying the optimized process conditions. HEWL appeared more effective in the immobilized form than in the free one, when the reactor was applied in real white and red wine. This preliminary study suggests that covalent immobilization renders the enzyme less sensitive to the inhibitory effect of wine flavans.

  10. [Study on CTP production from CMP by beer yeast cell immobilized in PVA].

    PubMed

    Yang, Hong-Yi; Qian, Shi-Jun; Li, Gao-Wo

    2007-03-01

    With PVA as the carrier, the frozen beer yeast cells were immobilized for production of CTP from CMP. we explored the optimal condition of the immobilization from the aspects of the type, concentration of the PVA, and the immobilizing methods of cells In all 8 continuous batch of fermentation under the reactional condition of the immobilized cells, the conversion rate of CTP were maintained about 85% - 95%. Moreever, the storage stability of immobilized cells were investigated, and the products was also isolated and identifided by HPLC.

  11. "Click" immobilization on alkylated silicon substrates: model for the study of surface bound antimicrobial peptides.

    PubMed

    Li, Yan; Santos, Catherine M; Kumar, Amit; Zhao, Meirong; Lopez, Analette I; Qin, Guoting; McDermott, Alison M; Cai, Chengzhi

    2011-02-25

    We describe an effective approach for the covalent immobilization of antimicrobial peptides (AMPs) to bioinert substrates via Cu(I) -catalyzed azide-alkyne cycloaddition (CuAAC). The bioinert substrates were prepared by surface hydrosilylation of oligo(ethylene glycol) (OEG) terminated alkenes on hydrogen-terminated silicon surfaces. To render the OEG monolayers "clickable", mixed monolayers were prepared using OEG-alkenes with and without a terminal alkyne protected by a trimethylgermanyl (TMG) group. The mixed monolayers were characterized by X-ray photoelectron spectroscopy (XPS), elliposometry and contact angle measurement. The TMG protecting group can be readily removed to yield a free terminal alkyne by catalytic amounts of Cu(I) in an aqueous media. This step can then be combined with the subsequent CuAAC reaction. Thus, the immobilization of an azide modified AMP (N3-IG-25) was achieved in a one-pot deprotection/coupling reaction. Varying the ratio of the two alkenes in the deposition mixture allowed for control over the density of the alkynyl groups in the mixed monolayer, and subsequently the coverage of the AMPs on the monolayer. These samples allowed for study of the dependence of antimicrobial activities on the AMP density. The results show that a relative low coverage of AMPs (∼1.6×10(13) molecule per cm(2)) is sufficient to significantly suppress the viability of Pseudomonas aeruginosa, while the surface presenting the highest density of AMPs (∼2.8×10(13) molecule per cm(2)) is still cyto-compatible. The remarkable antibacterial activity is attributed to the long and flexible linker and the site-specific "click" immobilization, which may facilitate the covalently attached peptides to interact with and disrupt the bacterial membranes.

  12. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    NASA Astrophysics Data System (ADS)

    Dien To, Thien; Nguyen, Anh Tuan; Nhat Thanh Phan, Khoa; Thu Thi Truong, An; Doan, Tin Chanh Duc; Mau Dang, Chien

    2015-12-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES.

  13. Glyphosate degradation by immobilized bacteria: field studies with industrial wastewater effluent.

    PubMed

    Hallas, L E; Adams, W J; Heitkamp, M A

    1992-04-01

    Immobilized bacteria have been shown in the laboratory to effectively remove glyphosate from wastewater effluent discharged from an activated sludge treatment system. Bacterial consortia in lab columns maintained a 99% glyphosate-degrading activity (GDA) at a hydraulic residence time of less than 20 min. In this study, a pilot plant (capacity, 45 liters/min) was used for a field demonstration. Initially, activated sludge was enriched for microbes with GDA during a 3-week biocarrier activation period. Wastewater effluent was then spiked with glyphosate and NH4Cl and recycled through the pilot plant column during start-up. Microbes with GDA were enhanced by maintaining the pH at less than 8 and adding yeast extract (less than 10 mg/liter). Once the consortia were stabilized, the column capacity for glyphosate removal was determined in a 60-day continuous-flow study. Waste containing 50 mg of glyphosate per liter was pumped at increasing flow rates until a steady state was reached. A microbial GDA of greater than 90% was achieved at a 10-min hydraulic residence time (144 hydraulic turnovers per day). Additional studies showed that microbes with GDA were recoverable within (i) 5 days of an acid shock and (ii) 3 days after a 21-day dormancy (low-flow, low-maintenance) mode. These results suggest that full-scale use of immobilized bacteria can be a cost-effective and dependable technique for the biotreatment of industrial wastewater.

  14. Polymeric brushes as functional templates for immobilizing ribonuclease A: study of binding kinetics and activity.

    PubMed

    Cullen, Sean P; Liu, Xiaosong; Mandel, Ian C; Himpsel, Franz J; Gopalan, Padma

    2008-02-05

    The ability to immobilize proteins with high binding capacities on surfaces while maintaining their activity is critical for protein microarrays and other biotechnological applications. We employed poly(acrylic acid) (PAA) brushes as templates to immobilize ribonuclease A (RNase A), which is commonly used to remove RNA from plasmid DNA preparations. The brushes are grown by surface-anchored atom-transfer radical polymerization (ATRP) initiators. RNase A was immobilized by both covalent esterification and a high binding capacity metal-ion complexation method to PAA brushes. The polymer brushes immobilized 30 times more enzyme compared to self-assembled monolayers. As the thickness of the brush increases, the surface density of the RNase A increases monotonically. The immobilization was investigated by ellipsometry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The activity of the immobilized RNase A was determined using UV absorbance. As much as 11.0 microg/cm(2) of RNase A was bound to PAA brushes by metal-ion complexation compared to 5.8 microg/cm(2) by covalent immobilization which is 30 and 16 times the estimated mass bound in a monolayer. The calculated diffusion coefficient D was 0.63 x 10(-14) cm(2)/s for metal-ion complexation and 0.71 x 10(-14) cm(2)/s for covalent immobilization. Similar values of D indicate that the binding kinetics is similar, but the thermodynamic equilibrium coverage varies with the binding chemistry. Immobilization kinetics and thermodynamics were characterized by ellipsometry for both methods. A maximum relative activity of 0.70-0.80 was reached between five and nine monolayers of the immobilized enzyme. However, the relative activity for covalent immobilization was greater than that of metal-ion complexation. Covalent esterification resulted in similar temperature dependence as free enzyme, whereas metal-ion complexation showed no

  15. Immobilized Kluyveromyces marxianus cells in carboxymethyl cellulose for production of ethanol from cheese whey: experimental and kinetic studies.

    PubMed

    Roohina, Fatemeh; Mohammadi, Maedeh; Najafpour, Ghasem D

    2016-09-01

    Cheese whey fermentation to ethanol using immobilized Kluyveromyces marxianus cells was investigated in batch and continuous operation. In batch fermentation, the yeast cells were immobilized in carboxymethyl cellulose (CMC) polymer and also synthesized graft copolymer of CMC with N-vinyl-2-pyrrolidone, denoted as CMC-g-PVP, and the efficiency of the two developed cell entrapped beads for lactose fermentation to ethanol was examined. The yeast cells immobilized in CMC-g-PVP performed slightly better than CMC with ethanol production yields of 0.52 and 0.49 g ethanol/g lactose, respectively. The effect of supplementation of cheese whey with lactose (42, 70, 100 and 150 g/l) on fermentative performance of K. marxianus immobilized in CMC beads was considered and the results were used for kinetic studies. The first order reaction model was suitable to describe the kinetics of substrate utilization and modified Gompertz model was quite successful to predict the ethanol production. For continuous ethanol fermentation, a packed-bed immobilized cell reactor (ICR) was operated at several hydraulic retention times; HRTs of 11, 15 and 30 h. At the HRT of 30 h, the ethanol production yield using CMC beads was 0.49 g/g which implies that 91.07 % of the theoretical yield was achieved.

  16. Spectroscopic study of 3-Hydroxyflavone - protein interaction in lipidic bi-layers immobilized on silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Voicescu, Mariana; Ionescu, Sorana; Nistor, Cristina L.

    2017-01-01

    The interaction of 3-Hydroxyflavone with serum proteins (BSA and HSA) in lecithin lipidic bi-layers (PC) immobilized on silver nanoparticles (SNPs), was studied by fluorescence and Raman spectroscopy. BSA secondary structure was quantified with a deconvolution algorithm, showing a decrease in α-helix structure when lipids were added to the solution. The effect of temperature on the rate of the excited-state intra-molecular proton transfer and on the dual fluorescence emission of 3-HF in the HSA/PC/SNPs systems was discussed. Evaluation of the antioxidant activity of 3-HF in HSA/PC/SNPs systems was also studied. The antioxidant activity of 3-HF decreased in the presence of SNPs. The results are discussed with relevance to the secondary structure of proteins and of the 3-HF based nano-systems to a topical formulation useful in the oxidative stress process.

  17. Biosorption of metal contaminants using immobilized biomass: A laboratory study. Rept. of Investigations/1991

    SciTech Connect

    Jeffers, T.H.; Ferguson, C.R.; Bennett, P.G.

    1991-01-01

    The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials for removing metal contaminants from waste waters. The beads, designated as BIO-FIX beads, are prepared by blending biomass, such as sphagnum peat moss or algae, into a polymer solution and spraying the mixture into water. Laboratory studies were conducted to determine bead sorption and elution characteristics. Batch and continuous tests demonstrated that BIO-FIX beads sorbed arsenic, cadmium, lead, and other toxic metals from acid mine drainage waters collected from several sites. Selectivity for heavy and toxic metal ions over calcium and magnesium was demonstrated. The beads exhibited excellent metal sorption and handling characteristics in stirred tanks, column contactors, and a low-maintenance passive system. The sorption process was reversible, and metal ions were eluted from the beads using dilute mineral acids. Cyclic tests indicated that the beads continued to extract metal ions after repeated loading-elution cycles.

  18. Gold nanoworms immobilized graphene oxide polymer brush nanohybrid for catalytic degradation studies of organic dyes

    NASA Astrophysics Data System (ADS)

    Mogha, Navin Kumar; Gosain, Saransh; Masram, Dhanraj T.

    2017-02-01

    In the present work, we report gold nanoparticles (AuNPs) on poly (dimethylaminoethyl methacrylate) (PDMAEMA) brushes immobilized reduced graphene oxide (Au/PDMAEMA/RGO) as catalyst for degradation kinetic studies of Rhodamine B (RB), Methyl Orange (MO) and Eosine Y (EY) dyes, having an excellent catalytic activity, as evident by the apparent rate constant (kapp), which is found to be 21.8, 26.2, and 8.7 (×10-3 s-1), for RB, MO and EY respectively. Au/PDMAEMA/RGO catalyst is easy to use, highly efficient, recyclable, which make it suitable for applications in waste water management. Foremost, synthesis of PDMAEMA brushes on graphene oxide is accomplished by Atom transfer radical polymerization method (ATRP), whereas AuNPs are synthesized by simple chemical reduction method.

  19. Microorganism immobilization

    DOEpatents

    Compere, Alicia L.; Griffith, William L.

    1981-01-01

    Live metabolically active microorganisms are immobilized on a solid support by contacting particles of aggregate material with a water dispersible polyelectrolyte such as gelatin, crosslinking the polyelectrolyte by reacting it with a crosslinking agent such as glutaraldehyde to provide a crosslinked coating on the particles of aggregate material, contacting the coated particles with live microorganisms and incubating the microorganisms in contact with the crosslinked coating to provide a coating of metabolically active microorganisms. The immobilized microorganisms have continued growth and reproduction functions.

  20. A noble technique a using force-sensing resistor for immobilization-device quality assurance: A feasibility study

    NASA Astrophysics Data System (ADS)

    Cho, Min-Seok; Kim, Tae-Ho; Kang, Seong-Hee; Kim, Dong-Su; Kim, Kyeong-Hyeon; Shin, Dong-Seok; Noh, Yu-Yun; Koo, Hyun-Jae; Cheon, Geum Seong; Suh, Tae Suk; Kim, Siyong

    2016-03-01

    Many studies have reported that a patient can move even when an immobilization device is used. Researchers have developed an immobilization-device quality-assurance (QA) system that evaluates the validity of immobilization devices. The QA system consists of force-sensing-resistor (FSR) sensor units, an electric circuit, a signal conditioning device, and a control personal computer (PC) with in-house software. The QA system is designed to measure the force between an immobilization device and a patient's skin by using the FSR sensor unit. This preliminary study aimed to evaluate the feasibility of using the QA system in radiation-exposure situations. When the FSR sensor unit was irradiated with a computed tomography (CT) beam and a treatment beam from a linear accelerator (LINAC), the stability of the output signal, the image artifact on the CT image, and changing the variation on the patient's dose were tested. The results of this study demonstrate that this system is promising in that it performed within the error range (signal variation on CT beam < 0.30 kPa, root-mean-square error (RMSE) of the two CT images according to presence or absence of the FSR sensor unit < 15 HU, signal variation on the treatment beam < 0.15 kPa, and dose difference between the presence and the absence of the FSR sensor unit < 0.02%). Based on the obtained results, we will volunteer tests to investigate the clinical feasibility of the QA system.

  1. Useful oriented immobilization of antibodies on chimeric magnetic particles: direct correlation of biomacromolecule orientation with biological activity by AFM studies.

    PubMed

    Marciello, Marzia; Filice, Marco; Olea, David; Velez, Marisela; Guisan, José M; Mateo, Cesar

    2014-12-16

    The preparation and performance of a suitable chimeric biosensor based on antibodies (Abs) immobilized on lipase-coated magnetic particles by means of a standing orienting strategy are presented. This novel system is based on hydrophobic magnetic particles coated with modified lipase molecules able to orient and further immobilize different Abs in a covalent way without any previous site-selective chemical modification of biomacromolecules. Different key parameters attending the process were studied and optimized. The optimal preparation was performed using a controlled loading (1 nmol Ab g(-1) chimeric support) at pH 9 and a short reaction time to recover a biological activity of about 80%. AFM microscopy was used to study and confirm the Abs-oriented immobilization on lipase-coated magnetic particles and the final achievement of a highly active and recyclable chimeric immune sensor. This direct technique was demonstrated to be a powerful alternative to the indirect immunoactivity assay methods for the study of biomacromolecule-oriented immobilizations.

  2. Study on the biodegradation of crude oil by free and immobilized bacterial consortium in marine environment.

    PubMed

    Chen, Qingguo; Li, Jingjing; Liu, Mei; Sun, Huiling; Bao, Mutai

    2017-01-01

    Five strains of bacteria, namely, Exiguobacterium sp. ASW-1, Pseudomonas aeruginosa strain ASW-2, Alcaligenes sp. ASW-3, Alcaligenes sp. ASS-1, and Bacillus sp. ASS-2, were isolated from the Zhejiang coast in China. The mixed flora of the five strains performed well with degrading 75.1% crude oil (1%, w/v) in 7 days. The calcium alginate-activated carbon embedding carrier was used to immobilize bacterial consortium. Immobilized cells performed better than free ones in variations of environmental factors containing incubated temperature, initial pH, salinity of the medium and crude oil concentration. The degradation process of crude oil by immobilized bacteria was accelerated compared with that of the free ones. Bacterial consortium showed better performance on biodegradation of normal alkanes than that of PAHs. Improvement of immobilization on the biodegradation efficiency of normal alkanes (31.9%) was apparently high than that of PAHs (1.9%).

  3. Study on the biodegradation of crude oil by free and immobilized bacterial consortium in marine environment

    PubMed Central

    Li, Jingjing; Liu, Mei; Sun, Huiling; Bao, Mutai

    2017-01-01

    Five strains of bacteria, namely, Exiguobacterium sp. ASW-1, Pseudomonas aeruginosa strain ASW-2, Alcaligenes sp. ASW-3, Alcaligenes sp. ASS-1, and Bacillus sp. ASS-2, were isolated from the Zhejiang coast in China. The mixed flora of the five strains performed well with degrading 75.1% crude oil (1%, w/v) in 7 days. The calcium alginate—activated carbon embedding carrier was used to immobilize bacterial consortium. Immobilized cells performed better than free ones in variations of environmental factors containing incubated temperature, initial pH, salinity of the medium and crude oil concentration. The degradation process of crude oil by immobilized bacteria was accelerated compared with that of the free ones. Bacterial consortium showed better performance on biodegradation of normal alkanes than that of PAHs. Improvement of immobilization on the biodegradation efficiency of normal alkanes (31.9%) was apparently high than that of PAHs (1.9%). PMID:28346510

  4. Plutonium Immobilization Project Binder Burnout and Sintering Studies (Milestone 6.6a)

    SciTech Connect

    Chandler, G.

    1999-10-28

    The Plutonium Immobilization Team has developed an integrated test program to understand and optimize the controlling variables for the sintering step of the plutonium immobilization process. Sintering is the key process step that controls the product minerology. It is expected that the sintering will be the limiting process step that controls the throughput of the production line. The goal of the current sintering test program is to better understand factors that affect the sintering process.

  5. [Study of the interaction of main potato glycoalkaloids in inhibition of immobilized butyryl cholinesterase].

    PubMed

    Arkhypova, V M; Dziadevych, S V; Jaffrezic-Renault, N; Martelet, C; Soldatkin, O P

    2006-01-01

    The interaction of main potato glycoalkaloids alpha-solanine and alpha-chaconine in inhibition of horse serum butyryl cholinesterases immobilized on the pH-sensitive field-effect transistors has been investigated. The method of isobol diagram of Loewe and Muishnek has been used for interpretation of results. It has been shown the alpha-chaconine inhibits the immobilized bytyryl cholinesterases more strongly than alpha-solanine, and their mixture has the addition effect.

  6. Immobilization of flavan-3-ols onto sensor chips to study their interactions with proteins and pectins by SPR

    NASA Astrophysics Data System (ADS)

    Watrelot, Aude A.; Tran, Dong Tien; Buffeteau, Thierry; Deffieux, Denis; Le Bourvellec, Carine; Quideau, Stéphane; Renard, Catherine M. G. C.

    2016-05-01

    Interactions between plant polyphenols and biomacromolecules such as proteins and pectins have been studied by several methods in solution (e.g. isothermal titration calorimetry, dynamic light scattering, nuclear magnetic resonance and spectrophotometry). Herein, these interactions were investigated in real time by Surface Plasmon Resonance (SPR) analysis after immobilization of flavan-3-ols onto a sensor chip surface. (-)-epicatechin, (+)-catechin and flavan-3-ol oligomers with an average degree of polymerization of 2 and 8 were chemically modified using N-(2-(tritylthio)ethyl)propiolamide in order to introduce a spacer unit onto the catecholic B ring. Modified flavan-3-ols were then immobilized onto a carboxymethylated dextran surface (CM5). Immobilization was validated and further verified by evaluating flavan-3-ol interaction with bovine serum albumin (BSA), poly-L-proline or commercial pectins. BSA was found to have a stronger association with monomeric flavan-3-ols than oligomers. SPR analysis of selected flavan-3-ols immobilized onto CM5 sensor chips showed a stronger association for citrus pectins than apple pectins, regardless of flavan-3-ol degree of polymerization.

  7. Biosorption of Cu(II) by immobilized microalgae using silica: kinetic, equilibrium, and thermodynamic study.

    PubMed

    Lee, Hongkyun; Shim, Eunjung; Yun, Hyun-Shik; Park, Young-Tae; Kim, Dohyeong; Ji, Min-Kyu; Kim, Chi-Kyung; Shin, Won-Sik; Choi, Jaeyoung

    2016-01-01

    Immobilized microalgae using silica (IMS) from Micractinium reisseri KGE33 was synthesized through a sol-gel reaction. Green algal waste biomass, the residue of M. reisseri KGE33 after oil extraction, was used as the biomaterial. The adsorption of Cu(II) on IMS was tested in batch experiments with varying algal doses, pH, contact times, initial Cu(II) concentrations, and temperatures. Three types of IMSs (IMS 14, 70, and 100) were synthesized according to different algal doses. The removal efficiency of Cu(II) in the aqueous phase was in the following order: IMS 14 (77.0%) < IMS 70 (83.3%) < IMS 100 (87.1%) at pH 5. The point of zero charge (PZC) value of IMS100 was 4.5, and the optimum pH for Cu(II) adsorption was 5. Equilibrium data were described using a Langmuir isotherm model. The Langmuir model maximum Cu(II) adsorption capacity (q m) increased with the algal dose in the following order: IMS 100 (1.710 mg g(-1)) > IMS 70 (1.548 mg g(-1)) > IMS 14 (1.282 mg g(-1)). The pseudo-second-order equation fitted the kinetics data well, and the value of the second-order rate constant increased with increasing algal dose. Gibbs free energies (ΔG°) were negative within the temperature range studied, which indicates that the adsorption process was spontaneous. The negative value of enthalpy (ΔH°) again indicates the exothermic nature of the adsorption process. In addition, SEM-energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses of the IMS surface reveal that the algal biomass on IMS is the main site for Cu(II) binding. This study shows that immobilized microalgae using silica, a synthesized biosorbent, can be used as a cost-effective sorbent for Cu(II) removal from the aqueous phase.

  8. Effects of Right Lower Limb Orthopedic Immobilization on Braking Function: An On-The-Road Experimental Study With Healthy Volunteers.

    PubMed

    Murray, Jean-Christophe; Tremblay, Marc-André; Corriveau, Hélène; Hamel, Mathieu; Cabana, François

    2015-01-01

    Little is known about how immobilization of the right lower limb might affect driving. The purpose of the present study was to evaluate the effect of 2 types of immobilization on the emergency braking time of healthy subjects during actual driving conditions. The emergency braking times of 14 healthy volunteers were assessed in a closed circuit under 3 conditions: wearing running shoes, wearing an Aircast Walker(®), or wearing a walking cast on their right lower limb. An instrumented car was used to measure the emergency braking times during braking tests with and without a distractor. The foot movement times were significantly increased with both immobilization devices compared with the running shoe (p < .01). The median total braking time with the running shoe during emergency braking without a distractor was 0.452 (interquartile range, 25th to 75th [IQR], 0.413 to 0.472) second. The results obtained with the Aircast Walker(®) or the walking cast were significantly longer (p < .01), at 0.480 (IQR, 0.431 to 0.537) second and 0.512 (IQR, 0.451 to 0.535) second, respectively. When a distractor was added, the total braking time with the running shoe, Aircast Walker(®), and walking cast was 0.489 (IQR, 0.429 to 0.575), 0.516 (IQR, 0.459 to 0.586), and 0.510 (IQR, 0.469 to 0.570) second, respectively, with no statistically significant differences among these 3 conditions. Wearing an immobilization device on the right lower limb minimally lengthens the emergency braking time in healthy drivers under actual driving conditions. Clinicians must nonetheless exercise caution when advising a driver wearing an orthopedic immobilization, because driving a motor vehicle is a complex psychomotor task that goes well beyond the emergency braking time.

  9. Study the biocatalyzing effect and mechanism of cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification.

    PubMed

    Li, Haibo; Guo, Jianbo; Lian, Jing; Xi, Zhenhua; Zhao, Lijun; Liu, Xiaoyu; Zhang, Chenxiao; Yang, Jingliang

    2014-06-01

    The biocatalyzing effect of a novel cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification process was studied with anthraquinone, 1,8-dichloroanthraquinone, 1,5-dichloroanthraquinone and 1,4,5,8-tetrachloroanthraquinone. The results showed that the immobilized 1,4,5,8-tetrachloroanthraquinone presented the best biocatalyzed effect which increased nitrite denitrification rate to 2.3-fold with 12 mmol/L 1,4,5,8-tetrachloroanthraquinone. The unequal biocatalyzing effect was due to the quantity and position of -Cl substituent in anthraquinone-structure. Moreover, the nitrite denitrification rate was increased with the oxidation reduction potential (ORP) values becoming more negative during the biocatalyzing process. The stabilized ORP value with 12 mmol/L immobilized 1,4,5,8-tetrachloroanthraquinone were 81 mV lower than the control. At the same time, the more OH(-) was produced with the higher nitrite removal rate achieved in the nitrite denitrification process. In addition, a positive linear correlation was found between the nitrite removal reaction constants k [gNO2(-)-N/(gVSS d)] and immobilized 1,4,5,8-tetrachloroanthraquinone concentration (C1,4,5,8-tetrachloroanthraquinone), which was k = 1.8443 C1,4,5,8-tetrachloroanthraquinone + 33.75(R(2) = 0.9411). The initial nitrite concentration of 179 mgNO2(-)-N/L resulted in the maximum nitrite removal rate, which was 6.526[gNO2(-)-N/(gVSS d)]. These results show that the application of cellulose acetate immobilized redox mediators (CE-RM) can be valuable for increasing nitrite denitrification rate.

  10. Sonoenzymatic decolourization of an azo dye employing immobilized horse radish peroxidase (HRP): a mechanistic study.

    PubMed

    Malani, Ritesh S; Khanna, Swati; Moholkar, Vijayanand S

    2013-07-15

    For degradation of biorefractory pollutants, enzymatic treatments and sonochemical treatments have shown high potential. A combined technique of sono-enzymatic treatment is of special interest as it has shown enhancement effect than the individual techniques. This work has attempted to give a mechanistic insight into the interaction of sonochemical and enzymatic treatments using immobilized horseradish peroxidase (HRP) enzyme on the decolourization of acid red dye (an azo dye). In order to segregate the effect of ultrasound and cavitation, experiments were conducted at elevated static pressure. The kinetic parameters of HRP, viz. Vmax and Km were marginally affected by immobilization. There was a minor change in pH optima and temperature optima for immobilized HRP (6.5, 25°C) from free HRP (7.0, 20-25°C). Though the specific activity of free enzyme (0.272U/mg) was found to be higher than the immobilized enzyme (0.104U/mg), immobilized enzyme exhibited higher stability (up to 3 cycles) and degradation potential than free enzyme in all experiments. The results revealed that the coupling of sonication and enzymatic treatment at high pressure in presence of polyethylene glycol (PEG) yielded the highest decolourization of acid red (61.2%). However, the total decolourization achieved with combined technique was lesser than the sum of individual techniques, indicating negative synergy between the sonochemical and enzymatic techniques.

  11. Sequential injection affinity chromatography utilizing an albumin immobilized monolithic column to study drug-protein interactions.

    PubMed

    Zacharis, Constantinos K; Kalaitzantonakis, Eftichios A; Podgornik, Ales; Theodoridis, Georgios

    2007-03-09

    In this study, sequential injection affinity chromatography was used for drug-protein interactions studies. The analytical system used consisted of a sequential injection analysis (SIA) manifold directly connected with convective interaction media (CIM) monolithic epoxy disks modified by ligand-immobilization of protein. A non-steroidal, anti-inflammatory drug, naproxen (NAP) and bovine serum albumin (BSA) were selected as model drug and protein, respectively. The SIA system was used for sampling, introduction and propulsion of drug towards to the monolithic column. Association equilibrium constants, binding capacity at various temperatures and thermodynamic parameters (free energy DeltaG, enthalpy DeltaH) of the binding reaction of naproxen are calculated by using frontal analysis mathematics. The variation of incubation time and its effect in on-line binding mode was also studied. The results indicated that naproxen had an association equilibrium constant of 2.90 x 10(6)M(-1) at pH 7.4 and 39 degrees C for a single binding site. The associated change in enthalpy (DeltaH) was -27.36 kcal mol(-1) and the change in entropy (DeltaS) was -73 cal mol(-1)K(-1) for a single type of binding sites. The location of the binding region was examined by competitive binding experiments using a biphosphonate drug, alendronate (ALD), as a competitor agent. It was found that the two drugs occupy the same class of binding sites on BSA. All measurements were performed with fluorescence (lambda(ext)=230 nm, lambda(em)=350 nm) and spectrophotometric detection (lambda=280 nm).

  12. Studies on immobilized Saccharomyces cerevisiae. III. Physiology of growth and metabolism on various supports

    SciTech Connect

    Bandyopadhyay, K.K.; Ghose, T.K.

    1982-04-01

    In earlier communications general analyses of rapid ethanol fermentation by Saccharomyces cerevisiae immobilized on inert supports were described. In this article physiology of growth and metabolism (parameters like rates of CO/sub 2/ evolution and O/sub 2/ uptake, respiratory quotient, and generation time) of Saccharomyces cerevisiae immobilized on different supports are reported. Values of the ratio of specific oxygen uptake rate for immobilized cells to free cells have been found to be 0.732, 0.781, and 0.785 for carrier A, carrier B, and covalently crosslinked controlled pore glass (CPG, specific surface area of 439 m/sup 2/ g/sup -1/), respectively. Rates of specific CO/sub 2/ evolution for immobilized cells to free cells for these supports are 0.784, 0.822, and 0.783, respectively. Marked reduction in generation time of Saccharomyces cerevisiae on all the supports has been observed. No change in size (4.8-5 ..mu..m) and specific growth rate (..mu../sub m/ = 0.275 h/sup -1/) of cells leaving the reactor has been observed.

  13. Study on contraction and relaxation of experimentally denervated and immobilized muscles: Comparison with dystrophic muscles

    NASA Technical Reports Server (NTRS)

    Takamori, M.; Tsujihata, M.; Mori, M.; Hazama, R.; Ide, Y.

    1980-01-01

    The contraction-relaxation mechanism of experimentally denervated and immobilized muscles of the rabbit is examined. Results are compared with those of human dystrophic muscles, in order to elucidate the role and extent of the neurotrophic factor, and the role played by the intrinsic activity of muscle in connection with pathogenesis and pathophysiology of this disease.

  14. An Experimental Study of Sand Transport over an Immobile Gravel Substrate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of a stepwise addition of sand to an immobile gravel bed on the sand transport rate and configuration of the sand bed was investigated in a laboratory flume channel. Detailed measurements of sand transport rate, bed texture, and bed topography were collected for four different discharge...

  15. Physical and chemical immobilization of choline oxidase onto different porous solid supports: Adsorption studies.

    PubMed

    Passos, Marieta L C; Ribeiro, David S M; Santos, João L M; Saraiva, M Lúcia M F S

    2016-08-01

    This work carries out for the first time the comparison between the physical and chemical immobilization of choline oxidase onto aminated silica-based porous supports. The influence on the immobilization efficiency of concentration, pH, temperature and contact time between the support and choline oxidase, was evaluated. The immobilization efficiency was estimated taking into consideration the choline oxidase activity, which was assessed by using cadmium telluride (CdTe) quantum dots (QDs), obtained by hydrothermal synthesis, as photoluminescent probes. Hydrogen peroxide produced by enzyme activity was capable of quenching CdTe QDs photoluminescence. The magnitude of the PL quenching process was directly related with the enzyme activity. By comparing the chemical process with the physical adsorption, it was observed that the latter provided the highest choline oxidase immobilization. The equilibrium data were analyzed using Langmuir and Freundlich isotherms and kinetic data were fitted to the pseudo-first-order and pseudo-second-order models. Thermodynamic parameters, such as Gibbs free energy and entropy were also calculated. These results will certainly contribute to the development of new sensing schemes for choline, taking into account the growing demand for its quantification in biological samples.

  16. Studies on immobilized Saccharomyces cerevisiae. II. Effect of temperature distribution on continuous rapid ethanol formation in molasses fermentation.

    PubMed

    Ghose, T K; Bandyopadhyay, K K

    1982-04-01

    Recently, considerable interest has been shown in the study and analysis of immobilized cell reactors. One of the major uses of such a reactor system is expected to be in ethanol production from carbohydrates. One distinct disadvantage of this system is carbon dioxide gas holdup associated with unsteady-state temperature distribution across the reactor. Taking into account the earlier published data and assuming steady-state-substrate balance, and unsteady-state energy balance, and an average gas holdup of 20% with the heat retained by the gas neglected, the average reaction rate in the differential element was computed. Finally, a mathematical model to predict steady-state temperature profile along the reactor was developed. It was verified with experimental data obtained from an immobilized yeast reactor column (1 m x 14.5 cm). The experimental data fit well those computed from the model within an accuracy of 5%.

  17. Antagonism of Gluconacetobacter diazotrophicus (a sugarcane endosymbiont) against Xanthomonas albilineans (pathogen) studied in alginate-immobilized sugarcane stalk tissues.

    PubMed

    Blanco, Yolanda; Blanch, María; Piñón, Dolores; Legaz, María-Estrella; Vicente, Carlos

    2005-04-01

    Xanthomonas albilineans, a pathogenic bacterium that produces leaf scald disease of sugarcane, secretes a xanthan-like gum that invades both xylem and phloem of the host. Xanthan production has been verified after experimental infection of stalk segments of healthy plants. Moreover, Gluconacetobacter diazotrophicus is a nitrogen-fixing endosymbiont of sugarcane plants that antagonizes with X. albilineans by impeding the production of the bacterial gum. The physiological basis of this antagonism has been studied using tissues of sugarcane stalks previously inoculated with the endosymbiont, then immobilized in calcium alginate and maintained in a culture medium for Gluconacetobacter. Under these conditions, bacteria infecting immobilized tissues are able to secrete to the medium a lysozyme-like bacteriocin that inhibits the growth of X. albilineans.

  18. Cervical Spine Immobilization in Sports Related Injuries: Review of Current Guidelines and a Case Study of an Injured Athlete

    PubMed Central

    Bhamra, JS; Morar, Y; Khan, WS; Deep, K; Hammer, A

    2012-01-01

    Cervical spine immobilization is an essential component of the ATLS® system. Inadequate training in the management of trauma calls and failure of early recognition can have disastrous consequences. Pre-hospital personnel are routinely involved more in the assessment and stabilization of patients in comparison to other health care professionals. This case study and review highlights the importance of early recognition, assessment and correct stabilization of cervical spine injuries both in the field and during the initial assessment in hospital. Inadequate assessment, immobilization and lack of standard guidelines on the management of suspected cervical spine trauma can result in secondary injury. Regular assessment and training of pre-hospital and medical personnel is essential to the proper management of these potentially devastating injuries. PMID:23248726

  19. Study of reaction parameters and kinetics of esterification of lauric acid with butanol by immobilized Candida antarctica lipase.

    PubMed

    Shankar, Sini; Agarwal, Madhu; Chaurasia, S P

    2013-12-01

    Esterification of lauric acid with n-butanol, catalyzed by immobilized Candida antarctica lipase (CAL) in aqueous-organic biphasic solvent system was studied. Effects of various reaction parameters on esterification were investigated, such as type and amount of solvent, amount of buffer, pH, temperature, speed of agitation, amount of enzyme, butanol and lauric acid. The most suitable reaction conditions for esterification were observed at 50 degrees C and pH 7.0 using 5000 micromoles of lauric acid, 7000 pmoles of butanol, 0.25 ml phosphate buffer, 1 ml of isooctane as the solvent and 50 mg of immobilized enzyme in the reaction medium at agitation speed of 150 rpm. Maximum esterification of 96.36% was acheived in 600 min of reaction time at n-butanol to lauric acid molar ratio of 1: 0.7. Kinetic study for the esterification of lauric acid with n-butanol using immobilized CAL was carried out and the kinetic constants were estimated by using non-linear regression method. The estimated value of Michaelis kinetic constants for butanol (KmBt) and acid (KmAc) were 451.56 (M) and 4.7 x 10(-7)(M), respectively and the value of dissociation constant (KBt) of the butanol-lipase complex was 9.41 x 10(7)(M). The estimated constants agreed fairly well with literature data.

  20. Solvent Stability Study with Thermodynamic Analysis and Superior Biocatalytic Activity of Burkholderia cepacia Lipase Immobilized on Biocompatible Hybrid Matrix of Poly(vinyl alcohol) and Hypromellose.

    PubMed

    Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2014-12-26

    In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (K(D)) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the K(D)-value was found to be less in cyclohexane (0.843 × 10(-3)) as compared to acetone (1.997 × 10(-3)), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (E(a)) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic efficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH(⧧)), entropy (ΔS(⧧)) and Gibb's free energy (ΔG(⧧)) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time.

  1. Differential effect of the shape of calcium alginate matrices on the physiology of immobilized neuroblastoma N2a and Vero cells: a comparative study.

    PubMed

    Kintzios, S; Yiakoumetis, I; Moschopoulou, G; Mangana, O; Nomikou, K; Simonian, A

    2007-11-30

    In order to investigate the effect of cell immobilization in calcium alginate gels on cell physiology, we immobilized Vero or N2a neuroblastoma cells in gels shaped either as spherical beads or as thin membrane layers. Throughout a culture period of 4 weeks cell viability, RNA and cytoplasmic calcium concentration and glutathione accumulation were assayed by fluorescence microscopy after provision of an appropriate dye. Non-elaborate culture conditions were applied throughout the experimental period in order to evaluate cell viability under less than optimal storage conditions. Vero cell proliferation was observed only in spherical beads, while N2a cell proliferation was observed in both configurations until the third week of culture. Increased [Ca2+]cyt could be associated with cell proliferation only when cells were immobilized in spherical beads, while a considerable decrease in the biosynthesis of reduced glutathione and RNA was observed in cells immobilized in thin membrane layers. The observed effects of the shape of the immobilization matrix may be due to differences in external mass transfer resistance. Therefore, depending on cell type, cell proliferation could have been promoted by either increased (Vero) or decreased (N2a) nutrient and oxygen flow to immobilized cells. The results of the present study could contribute to an improvement of immobilized cell sensor storability.

  2. Immobilization of Cd in landfill-leachate-contaminated soil with cow manure compost as soil conditioners: A laboratory study.

    PubMed

    Liao, Zhuwei; Wang, Jia; Wan, Rui; Xi, Shuang; Chen, Zhuqi; Chen, Zhulei; Yu, Yingjian; Long, Sijie; Wang, Huabin

    2016-12-01

    Introducing cow manure compost as an amendment in landfill-leachate-contaminated soils is proved to be an effective technique for the immobilization of Cd in this study. Landfill-leachate-contaminated soil was collected from an unlined landfill in China and amended with a different blending quantity of cow manure compost (0, 12, 24, 36, and 48 g per 200 g soil), which was made by mixing cow manure and chaff at a ratio of 1/1 and maturing for 6 months. pH values of five different blending quantity mixtures increased by 0.2-0.4, and the organic matter levels increased by 2.5-7%, during a remediation period of 5 weeks. Four fractions of Cd named exchangeable Cd, reducible Cd, oxidizable Cd, and residual Cd in soil were respectively analyzed by a sequential extraction procedure. Introducing the cow manure compost application resulted in more than 40% lower exchangeable Cd but a higher concentration of oxidizable Cd in soils, and mass balance results showed nearly no Cd absorption by applied material, indicating that transformation of exchangeable Cd into oxidization forms was the main mechanism of Cd immobilization when cow manure compost was used as an amendment. The Pearson correlation showed that increasing of pH values significantly improved the efficiency of Cd immobilization, with a correlation coefficiency of 0.940 (p < 0.05). This is the first attempt at heavy metal immobilization in landfill-leachate-contaminated soil by cow manure compost, and findings of this work can be integrated to guide the application.

  3. PRELIMINARY STUDY OF CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

    SciTech Connect

    Fox, K.; Billings, A.; Brinkman, K.; Marra, J.

    2010-09-22

    The Savannah River National Laboratory (SRNL) developed a series of ceramic waste forms for the immobilization of Cesium/Lanthanide (CS/LN) and Cesium/Lanthanide/Transition Metal (CS/LN/TM) waste streams anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores, zirconolite, and other minor metal titanate phases. Identification of excess Al{sub 2}O{sub 3} via X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. XRD and SEM/EDS results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD, and had phase assemblages that were closer to the initial targets. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms. Initial studies of radiation damage tolerance using ion beam irradiation at Los

  4. Uranium Immobilization through Fe(II) bio-oxidation: A Column study

    SciTech Connect

    Coates, John D.

    2009-09-14

    Current research on the bioremediation of heavy metals and radionuclides is focused on the ability of reducing organisms to use these metals as alternative electron acceptors in the absence of oxygen and thus precipitate them out of solution. However, many aspects of this proposed scheme need to be resolved, not the least of which is the time frame of the treatment process. Once treatment is complete and the electron donor addition is halted, the system will ultimately revert back to an oxic state and potentially result in the abiotic reoxidation and remobilization of the immobilized metals. In addition, the possibility exists that the presence of more electropositive electron acceptors such as nitrate or oxygen will also stimulate the biological oxidation and remobilization of these contaminants. The selective nitrate-dependent biooxidation of added Fe(II) may offer an effective means of “capping off” and completing the attenuation of these contaminants in a reducing environment making the contaminants less accessible to abiotic and biotic reactions and allowing the system to naturally revert to an oxic state. Our previous DOE-NABIR funded studies demonstrated that radionuclides such as uranium and cobalt are rapidly removed from solution during the biogenic formation of Fe(III)-oxides. In the case of uranium, X-ray spectroscopy analysis indicated that the uranium was in the hexavalent form (normally soluble) and was bound to the precipitated Fe(III)-oxides thus demonstrating the bioremediative potential of this process. We also demonstrated that nitrate-dependent Fe(II)- oxidizing bacteria are prevalent in the sediment and groundwater samples collected from sites 1 and 2 and the background site of the NABIR FRC in Oakridge, TN. However, all of these studies were performed in batch experiments in the laboratory with pure cultures and although a significant amount was learned about the microbiology of nitrate-dependent bio-oxidation of Fe(II), the effects of

  5. Immobilization of proteins on boron nitride nanotubes.

    PubMed

    Zhi, Chunyi; Bando, Yoshio; Tang, Chengchun; Golberg, Dmitri

    2005-12-14

    We report for the first time that proteins are immobilized on boron nitride nanotubes. It is found that there is a natural affinity of a protein to BNNT; this means that it can be immobilized on BNNT directly, without usage of an additional coupling reagent. For the most effective immobilization, noncovalently functionalized BNNTs should be used. The effect of immobilization was studied using high-resolution transmission electron microscopy and energy dispersion spectroscopy.

  6. Integrated immobilized cell reactor-adsorption system for beta-cyclodextrin production: a model study using PVA-cryogel entrapped Bacillus agaradhaerens cells.

    PubMed

    Martins, Rita F; Plieva, Fatima M; Santos, Ana; Hatti-Kaul, Rajni

    2003-09-01

    Production of cyclodextrins (CDs) by immobilized cells of the alkaliphilic Bacillus agaradhaerens LS-3C with integrated product recovery was studied. The microorganism was entrapped in polyvinyl alcohol-cryogel beads and used as a convenient source of immobilized cyclodextrin glycosyltransferase (CGTase). On activation by incubation in the cultivation medium containing 1% (w/v) starch, the entrapped cells multiplied and secreted CGTase with an activity of 2-3 mg beta-cyclodextrin h(-1) g(-1) beads. The immobilized biocatalyst exhibited maximum activity at pH 9 and 50 degrees C, and formed cyclodextrins comprising 92-94% beta-CD and remaining alpha-CD. The cyclodextrin product from the immobilized cell bioreactor was continuously recovered by adsorption to Amberlite XAD-4 in a recycle batch mode. The product adsorption was facilitated at low temperature while hot water was used for elution.

  7. Comparative study of controlled pore glass, silica gel and poraver for the immobilization of urease to determine urea in a flow injection conductimetric biosensor system.

    PubMed

    Limbut, Warakorn; Thavarungkul, Panote; Kanatharana, Proespichaya; Asawatreratanakul, Punnee; Limsakul, Chusak; Wongkittisuksa, Booncharoen

    2004-03-15

    This study compared the responses of three enzyme reactors containing urease immobilized on three types of solid support, controlled pore glass (CPG), silica gel and Poraver. The evaluation of each enzyme reactor column was done in a flow injection conductimetric system. When urea in the sample solution passed though the enzyme reactor, urease catalysed the hydrolysis of urea into charged products. A lab-built conductivity meter was used to measure the increase in conductivity of the solution. The responses of the enzyme reactor column with urease immobilized on CPG and silica gel were similar and were much higher than that of Poraver. Both CPG and silica gel reactor columns gave the same limit of detection, 0.5 mM, and the response was still linear up to 150mM. The analysis time was 4-5 min per sample. The enzyme reactor column with urease immobilized on CPG gave a slightly better sensitivity, 4% higher than the reactor with silica gel. The life time of the immobilized urease on CPG and silica gel were more than 310h operation time (used intermittently over 7 months). Good agreement was obtained when urea concentrations of human serum samples determined by the flow injection conductimetric biosensor system was compared to the conventional methods (Fearon and Berthelot reactions). These were statistically shown using the regression line and Wilcoxon signed rank tests. The results showed that the reactor with urease immobilized on silica gel had the same efficiency as the reactor with urease immobilized on CPG.

  8. Sulfur immobilization and lithium storage on defective graphene: A first-principles study

    NASA Astrophysics Data System (ADS)

    Zhao, Wen; Chen, Pengcheng; Tang, Peizhe; Li, Yuanchang; Wu, Jian; Duan, Wenhui

    2014-01-01

    Motivated by the recent progresses and remaining technical challenges in Li-S battery, we employ defective graphene as a prototype cathode framework to illustrate how battery performance is influenced by the mesoporous carbon materials. We show that the immobilization of S unavoidably sacrifices its ability to further interact with Li, which leads to an enhanced cycle life but a decreased capacity. Based on our calculated results, we suggest a suitable S binding-energy range of ˜4-5 eV to balance the battery stability and capability under thermodynamic equilibrium conditions. Our results may promote the understanding and architecture design of Li-S battery.

  9. Formulation Study on Immobilization of Spent Ion Exchange Resins in Polymer Cements

    SciTech Connect

    Lili Xia; Meiqiong Lin; Bao Liangjin

    2006-07-01

    Applying normal design and correlative computer software, a new matrix material and an excellent waste formulation were developed. Based on the theory calculations and normal design in this paper, using polymer complex cement as immobilization matrix that mixed with simulating spent ion exchange resin a new waste formulation was carried out. The characterization of solidified waste had been done after 28 days curing. The results conformed to the treatment of the waste about the requests of the national standard [GB14569-93-1]. Leach index of the solidified waste was excellent. An optimized formulation was recommended. (authors)

  10. “Click” Immobilization on Alkylated Silicon Substrates: Model for the Study of Surface Bound Antimicrobial Peptides

    PubMed Central

    Li, Yan; Santos, Catherine M.; Kumar, Amit; Zhao, Meirong; Lopez, Analette I.; Qin, Guoting; McDermott, Alison M.

    2011-01-01

    We describe an effective approach for the covalent immobilization of antimicrobial peptides (AMPs) to bioinert substrates via CuI-catalyzed azide–alkyne cycloaddition (CuAAC). The bioinert substrates were prepared by surface hydrosilylation of oligo-(ethylene glycol) (OEG) terminated alkenes on hydrogen-terminated silicon surfaces. To render the OEG monolayers “clickable”, mixed monolayers were prepared using OEG-alkenes with and without a terminal alkyne protected by a trimethylgermanyl (TMG) group. The mixed monolayers were characterized by X-ray photoelectron spectroscopy (XPS), elliposometry and contact angle measurement. The TMG protecting group can be readily removed to yield a free terminal alkyne by catalytic amounts of CuI in an aqueous media. This step can then be combined with the subsequent CuAAC reaction. Thus, the immobilization of an azide modified AMP (N3-IG-25) was achieved in a one-pot de-protection/coupling reaction. Varying the ratio of the two alkenes in the deposition mixture allowed for control over the density of the alkynyl groups in the mixed monolayer, and subsequently the coverage of the AMPs on the monolayer. These samples allowed for study of the dependence of antimicrobial activities on the AMP density. The results show that a relative low coverage of AMPs (~1.6×1013 molecule per cm2) is sufficient to significantly suppress the viability of Pseudomonas aeruginosa, while the surface presenting the highest density of AMPs (~2.8×1013 molecule per cm2) is still cyto-compatible. The remarkable antibacterial activity is attributed to the long and flexible linker and the site-specific “click” immobilization, which may facilitate the covalently attached peptides to interact with and disrupt the bacterial membranes. PMID:21264959

  11. Comparative study of the nitrification characteristics of two different nitrifier immobilization methods.

    PubMed

    Li, Zhirong; Zhang, Zhi; Li, Jun; Zhang, Zhenjia

    2009-11-01

    The research investigated the nitrification characteristics of two different immobilization methods: nitrifier encapsulation in polyethylene glycol (PEG) gel pellets and nitrifier biofilm attachment on elastic plastic filler. The two carriers were placed in identical reactors. They reached a maximum nitrification rate of 39 and 25 mgN/L.h 30 days after start-up. The results showed that the nitrification efficiency in the PEG reactor was higher than in the biofilm reactor under the same conditions. Variations in temperature decreased the nitrification rate by approximately 55% in the PEG reactor from 28 to 8 degrees C, while 74.2% in the biofilm reactor. When the COD loading rate was increased to 0.8 kg/m(3) day, the nitrification efficiency in the biofilm reactor dropped sharply to 23%, and that of PEG reactor remained over 80%. PEG pellets with a high nitrification rate under all conditions showed promise as an immobilization medium, and are likely to be utilized in the nitrification of high-strength ammonia and COD wastewater during long-term operation.

  12. [An FTIR and XPS study of immobilization of chromium with fly ash based geopolymers].

    PubMed

    Liu, Si-Feng; Wang, Pei-Ming; Li, Zong-Jin; Lo, Irene M C

    2008-01-01

    Immobilization of Cr3+ with fly ash geopolymers was investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopic (XPS) techniques. The chromium sludge, as Cr(OH)3, was prepared with chemical precipitation method. The amounts of aluminum and silicon leached before and after the chromium sludge addition were measured using ICP-AES. The results suggested that the amounts of silicon and aluminum leached were reduced for the fly ash geopolymers after chromium sludge was incorporated. The decrease of silicon leaching was more pronounced than aluminum. FTIR results showed that the intensity of the main peak shifted into lower and the wave number of Si--O--Si and Al--O--Si became higher. The XPS results indicated that the O(1s) bind energy decreased, Si(2p) and Cr(2p) bind energy increased, while Al(2p) bind energy remained unchanged due to Cr3+ addition. It was also confirmed that the chromium is easily incorporated into the fly ash geopolymers paste, and polymerized with silicate units. The immobilization of Cr3+ using fly ash geopolymers is attributed not only to physical encapsulation, but also to chemical reaction.

  13. Si-F complexing in aqueous fluids: experimental study and implications for transport of immobile elements

    NASA Astrophysics Data System (ADS)

    Dolejš, David

    2014-05-01

    Intepretation of fluid-mineral interaction mechanisms and hydrothermal fluxes requires knowledge of predominant solubility and speciation reactions and their thermodynamic properties. Fluorine represents a hard electron donor, capable of complexing and transporting high-field strength elements, which are traditionally considered to be immobile. Reactions responsible for element mobility have general form MOx + y HF (aq) + x - y H2O = M(OH)2x-yFy (aq), and their extent and transport efficiency relies on hydrogen fluoride activity. In natural fluids, a[HF] is controlled by various fluorination equilibria including neutralization of silicates with consequent formation of silicohydroxyfluoride complexes. Quartz solubility in HF-H2O fluids was experimentally determined at 400-800 oC and 100-200 MPa using rapid-quench cold-seal pressure vessels and the mineral weight-loss method. Quartz solubility significantly increases in the presence of hydrogen fluoride: at 400 oC and 100 MPa, dissolved SiO2 ranges from 0.18 wt. % in pure H2O to 12.2 wt. % at 8.3 wt. % F in the fluid, whereas at 800 oC and 200 MPa it rises from 1.51 wt. % in pure H2O to 15.3 wt. % at 8.0 wt. % F in the fluid. The isobaric solubilities of quartz appear to be temperature-independent, i.e., effects of temperature vs. fluid density on the solubility are counteracting. The experimental data are described by the density model: log m[SiO2] = a + blog ρ + clog m[F] + dT , where a = -1.049 mol kg-1, b = 0.816 mol cm-3, c = 0.802 and d = 1.256 · 10-3 mol kg-1 K-1. Solubility isotherms have similar d(log m[SiO2])/d(log m[F]) slopes over the entire range of conditions indicating that Si(OH)2F2 is the major aqueous species. Several factors promote breakdown of silicohydroxyfluoride complexes and precipitation of silica solute: (i) decreasing temperature and pressure, i.e., fluid ascent and cooling and/or (ii) neutralization and increase in the alkali/H ratio of fluids during alteration reactions or removal of

  14. Kinetic Measurements for Enzyme Immobilization.

    PubMed

    Cooney, Michael J

    2017-01-01

    Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of this enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten were advancing their work by studying the kinetics of an enzyme saccharase which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis and ever since the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, and selectivity towards nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adapted to the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V max, K M) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

  15. Kinetic measurements for enzyme immobilization.

    PubMed

    Cooney, Michael J

    2011-01-01

    Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of the enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten had advanced this work by studying the kinetics of the enzyme saccharase, which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis, and ever since, the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, selectivity toward nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adopted for the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V(max), K(M)) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review, enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

  16. Evaluation of antifertility effect of gel formulation containing sperm immobilizing factor: In vitro and in vivo studies.

    PubMed

    Gupta, Sonia; Kaur, Indu Pal; Prabha, Vijay

    2016-01-01

    Sexually active women often seek protection against unplanned pregnancies. Latter can be effectively controlled by consistent use of spermicides during each coital act. However, side effects associated with the use of available synthetic spermicidal agents have directed the interest towards identifying newer and safer agents. Present studies were undertaken to formulate a vaginal contraceptive gel, containing sperm immobilizing factor (SIF) isolated from Staphylococcus aureus using 1% w/v Carbopol. SIF loaded gel formulation was characterized for various in vitro parameters i.e. pH, spreadability, texture profiling, rheological properties, and in vitro release studies. The prepared formulation was found to possess significant spreading properties, gel firmness and strength, and released about 80% of SIF within 30min. Latter can completely immobilize human spermatozoa within 20s, at a dose of 200μg/ml. SIF in the proposed gel formulation showed 100% contraceptive effect when used at amount as low as of 10μg, thus confirming the possibility to develop it as a potent vaginal contraceptive for future use.

  17. Treatment of textile effluent in a developed phytoreactor with immobilized bacterial augmentation and subsequent toxicity studies on Etheostoma olmstedi fish.

    PubMed

    Watharkar, Anuprita D; Khandare, Rahul V; Waghmare, Pankajkumar R; Jagadale, Ashwini D; Govindwar, Sanjay P; Jadhav, Jyoti P

    2015-01-01

    A static hydroponic bioreactor using nursery grown plants of Pogonatherum crinitum along with immobilized Bacillus pumilus cells was developed for the treatment of textile wastewater. Independent reactors with plants and immobilized cells were also kept for performance and efficacy evaluation. The effluent samples characterized before and after their treatment showed that the plant-bacterial consortium reactor was more efficient than those of individual plant and bacterium reactors. COD, BOD, ADMI, conductivity, turbidity, TDS and TSS of the textile effluent was found to be reduced by 78, 70, 93, 4, 90, 13 and 70% respectively within 12 d by the consortial set. HPTLC analysis revealed the transformation of the textile effluent to new products. The phytotoxicity study on Phaeseolus mungo and Sorghum vulgare seeds showed reduced toxicity of treated effluents. The animal toxicity study performed on Etheostoma olmstedi fishes showed the toxic nature of untreated effluent giving extreme stress to fishes leading to death. Histology of fish gills exposed to treated effluent was found to be less affected. The oxidative stress related enzymes like superoxide dismutase and catalase were found to show decreased activities and less lipid peroxidation in fishes exposed to treated effluent.

  18. A density functional theory study of arsenic immobilization by the Al(III)-modified zeolite clinoptilolite.

    PubMed

    Awuah, Joel B; Dzade, Nelson Y; Tia, Richard; Adei, Evans; Kwakye-Awuah, Bright; Richard A Catlow, C; de Leeuw, Nora H

    2016-04-28

    We present density functional theory calculations of the adsorption of arsenic acid (AsO(OH)3) and arsenous acid (As(OH)3) on the Al(III)-modified natural zeolite clinoptilolite under anhydrous and hydrated conditions. From our calculated adsorption energies, we show that adsorption of both arsenic species is favorable (associative and exothermic) under anhydrous conditions. When the zeolite is hydrated, adsorption is less favourable, with the water molecules causing dissociation of the arsenic complexes, although exothermic adsorption is still observed for some sites. The strength of interaction of the arsenic complexes is shown to depend sensitively on the Si/Al ratio in the Al(III)-modified clinoptilolite, which decreases as the Si/Al ratio increases. The calculated large adsorption energies indicate the potential of Al(iii)-modified clinoptilolite for arsenic immobilization.

  19. Study of concentration of HPV DNA probe immobilization for cervical cancer detection based IDE biosensor

    NASA Astrophysics Data System (ADS)

    Roshila, M. L.; Hashim, U.; Azizah, N.

    2016-07-01

    This paper mainly illustrates regarding the detection process of Human Papillomavirus (HPV) DNA probe. HPV is the most common virus that infected to human by a sexually transmitted virus. The most common high-risk HPV are 16 and 18. Interdigitated electrode (IDE) device used as based of Titanium Dioxide (TiO2) acts as inorganic surface, where by using APTES as a linker between inorganic surface and organic surface. A strategy of rapid and sensitive for the HPV detection was proposed by integrating simple DNA extraction with a gene of DNA. The extraction of the gene of DNA will make an efficiency of the detection process. It will depend on the sequence of the capture probes and the way to support their attached. The fabrication, surface modification, immobilization and hybridization processes are characterized by current voltage (I-V) measurement by using KEITHLEY 6487. This strategy will perform a good sensitivity of HPV detection.

  20. Method for immobilizing microbial cells on gel surface for dynamic AFM studies.

    PubMed Central

    Gad, M; Ikai, A

    1995-01-01

    The processes of cell growth and budding of the yeast cells Saccharomyces cerevisiae, which were gently immobilized on 3% agar and submerged in culture medium, were successfully imaged with an atomic force microscope for 6-7 h. Similar experiments on chemically fixed cells did not detect any appreciable change in their appearance except in a few scannings at the very beginning, indicating that the dissolution of agar and/or scraping of its surface by the scanning tip, if any, did not significantly interfere with the images taken thereafter. The increment in the height of many of the untreated cells, accompanied by their lateral enlargement, was taken as an indication of successful imaging of the growth process of yeast cells, together with an image of a growing daughter cell attached to its mother cell. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 5 FIGURE 7 FIGURE 8 PMID:8599630

  1. Bio-functionalization of electro-synthesized polypyrrole surface by heme enzyme using a mixture of Nafion and glutaraldehyde as synergetic immobilization matrix: Conformational characterization and electrocatalytic studies

    NASA Astrophysics Data System (ADS)

    ElKaoutit, Mohammed; Naranjo-Rodriguez, Ignacio; Domínguez, Manuel; Hidalgo-Hidalgo-de-Cisneros, José Luis

    2011-10-01

    Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seems to have been introduced inside the ionic cluster of Nafion. The characterization of the resulting bio-interfaces by UV-vis and FT-IR shows that the intra-crosslinkage phenomena caused by the use of glutaraldehyde can be eliminated by the optimization of the concentration of Nafion additive. The secondary structure contents of native and immobilized enzyme were analyzed by a Gaussian curve fitting of the respective FT-IR spectra in the amide I region. Immobilized enzyme presented notable increasing percentages of globular and short helical structure compared with native enzyme. This indicates that immobilized enzyme was folded which is in accordance with AFM studies and supports the enzyme entrance inside ionic clutter of Nafion. Thanks to synergic effects of the polypyrrole conducting polymer and the perfluorosulfonic acid polymer Nafion, HRP enzyme was immobilized in its "native" state, the resulting biosensor was able to sense peroxide without any chemical mediator and can be categorized as third generation.

  2. Chemically immobilized and physically adsorbed PAN/acetylacetone modified mesoporous silica for the recovery of rare earth elements from the waste water-comparative and optimization study.

    PubMed

    Ramasamy, Deepika Lakshmi; Repo, Eveliina; Srivastava, Varsha; Sillanpää, Mika

    2017-05-01

    This study was aimed at the investigation of Rare Earth Element (REE) recovery from aqueous solution by silica gels with 1-(2-Pyridylazo) 2-naphthol (PAN) and acetyl acetone (Acac) modifications. The two different methods of silica gel chelation, such as chemical immobilization with the help of silane coupling agents (3-aminopropyl triethoxysilane (APTES) and 3-aminopropyl trimethoxysilane (APTMS) in this study) and direct physical adsorption onto the silica surface, is compared in terms of their REE removal efficiency. A comparative analysis between adsorption of different REEs for different silica gels is performed and the influence of parameters such as pH, contact time, temperature and initial concentration has been reported. The effect of calcined adsorbents on the adsorption process is also investigated. Characterization studies on silica gels by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD) and zeta potential analysis are performed to better understand the relation between physical/chemical attributes of the adsorbents and their impact on the adsorption process. The experimental results are evaluated and optimal conditions for REE adsorption are identified. Chemically immobilized gels demonstrated immense potential for all the REE under study except Sc, for which, physically loaded gels seemed to be more efficient. The removal of REEs could be achieved at lower pHs by chemically immobilized PAN/Acac gels, making it suitable for many practical applications. The amine functionalized gels before chemical immobilization step were compared with PAN/Acac chemically immobilized gels in single as well as multi element system and the significance of chemical immobilization after amine functionalization is also stated.

  3. Protein immobilization techniques for microfluidic assays

    PubMed Central

    Kim, Dohyun; Herr, Amy E.

    2013-01-01

    Microfluidic systems have shown unequivocal performance improvements over conventional bench-top assays across a range of performance metrics. For example, specific advances have been made in reagent consumption, throughput, integration of multiple assay steps, assay automation, and multiplexing capability. For heterogeneous systems, controlled immobilization of reactants is essential for reliable, sensitive detection of analytes. In most cases, protein immobilization densities are maximized, while native activity and conformation are maintained. Immobilization methods and chemistries vary significantly depending on immobilization surface, protein properties, and specific assay goals. In this review, we present trade-offs considerations for common immobilization surface materials. We overview immobilization methods and chemistries, and discuss studies exemplar of key approaches—here with a specific emphasis on immunoassays and enzymatic reactors. Recent “smart immobilization” methods including the use of light, electrochemical, thermal, and chemical stimuli to attach and detach proteins on demand with precise spatial control are highlighted. Spatially encoded protein immobilization using DNA hybridization for multiplexed assays and reversible protein immobilization surfaces for repeatable assay are introduced as immobilization methods. We also describe multifunctional surface coatings that can perform tasks that were, until recently, relegated to multiple functional coatings. We consider the microfluidics literature from 1997 to present and close with a perspective on future approaches to protein immobilization. PMID:24003344

  4. Effect of computerized cognitive training with virtual spatial navigation task during bed rest immobilization and recovery on vascular function: A pilot study

    PubMed Central

    Goswami, Nandu; Kavcic, Voyko; Marusic, Uros; Simunic, Bostjan; Rössler, Andreas; Hinghofer-Szalkay, Helmut; Pisot, Rado

    2015-01-01

    We investigated the effects of bed rest (BR) immobilization, with and without computerized cognitive training with virtual spatial navigation task (CCT), on vascular endothelium on older subjects. The effects of 14-day BR immobilization in healthy older males (n=16) of ages 53–65 years on endothelial function were studied using EndoPAT®, a noninvasive and user-independent method. From the group of 16 older men, 8 randomly received CCT during the BR, using virtual navigation tasks in a virtual environment with joystick device. In all the cases, EndoPAT assessments were done at pre- and post-BR immobilization as well as following 28 days of ambulatory recovery. The EndoPAT index increased from 1.53±0.09 (mean ± standard error of the mean) at baseline to 1.61±0.16 following immobilization (P=0.62) in the group with CCT. The EndoPAT index decreased from 2.06±0.13 (mean ± standard error of the mean) at baseline to 1.70±0.09 at the last day of BR study, day 14 (BR14) (P=0.09) in the control group. Additionally, there were no statistically significant differences between BR14 and at 28 days of follow-up (rehabilitation program) (R28). Our results show a trend of immobilization in older persons affecting the vasoconstrictory endothelial response. As the control subjects had a greater increase in EndoPAT index after R28 (+0.018) compared to subjects who had cognitive training (+0.11) (calculated from the first day of BR study), it is possible that cognitive training during BR does not improve endothelial function but rather contributes to slowing down the impairment of endothelial function. Finally, our results also show that EndoPAT may be a useful noninvasive tool to assess the vascular reactivity. PMID:25709419

  5. Production of L-glutamic Acid with Corynebacterium glutamicum (NCIM 2168) and Pseudomonas reptilivora (NCIM 2598): A Study on Immobilization and Reusability

    PubMed Central

    Shyamkumar, Rajaram; Moorthy, Innasi Muthu Ganesh; Ponmurugan, Karuppiah; Baskar, Rajoo

    2014-01-01

    Background L-glutamic acid is one of the major amino acids that is present in a wide variety of foods. It is mainly used as a food additive and flavor enhancer in the form of sodium salt. Corynebacterium glutamicum (C. glutamicum) is one of the major organisms widely used for glutamic acid production. Methods The study was dealing with immobilization of C. glutamicum and mixed culture of C. glutamicum and Pseudomonas reptilivora (P. reptilivora) for L-glutamic acid production using submerged fermentation. 2, 3 and 5% sodium alginate concentrations were used for production and reusability of immobilized cells for 5 more trials. Results The results revealed that 2% sodium alginate concentration produced the highest yield (13.026±0.247 g/l by C. glutamicum and 16.026±0.475 g/l by mixed immobilized culture). Moreover, reusability of immobilized cells was evaluated in 2% concentration with 5 more trials. However, when the number of cycles increased, the production of L-glutamic acid decreased. Conclusion Production of glutamic acid using optimized medium minimizes the time needed for designing the medium composition. It also minimizes external contamination. Glutamic acid production gradually decreased due to multiple uses of beads and consequently it reduces the shelf life. PMID:25215180

  6. Energy transfer between surface-immobilized light-harvesting chlorophyll a/b complex (LHCII) studied by surface plasmon field-enhanced fluorescence spectroscopy (SPFS).

    PubMed

    Lauterbach, Rolf; Liu, Jing; Knoll, Wolfgang; Paulsen, Harald

    2010-11-16

    The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants can be viewed as a protein scaffold binding and positioning a large number of pigment molecules that combines rapid and efficient excitation energy transfer with effective protection of its pigments from photobleaching. These properties make LHCII potentially interesting as a light harvester (or a model thereof) in photoelectronic applications. Most of such applications would require the LHCII to be immobilized on a solid surface. In a previous study we showed the immobilization of recombinant LHCII on functionalized gold surfaces via a 6-histidine tag (His tag) in the protein moiety. In this work the occurrence and efficiency of Förster energy transfer between immobilized LHCII on a functionalized surface have been analyzed by surface plasmon field-enhanced fluorescence spectroscopy (SPFS). A near-infrared dye was attached to some but not all of the LHC complexes, serving as an energy acceptor to chlorophylls. Analysis of the energy transfer from chlorophylls to this acceptor dye yielded information about the extent of intercomplex energy transfer between immobilized LHCII.

  7. Pilot Study to Evaluate Hydrogen Injection for Stimulating Reduction and Immobilization of Uranium in Groundwater at an ISR Mining Site

    NASA Astrophysics Data System (ADS)

    Clapp, L. W.; Cabezas, J.; Gamboa, Y.; Fernandez, W.

    2011-12-01

    State and federal regulations require that groundwater at in-situ recovery (ISR) uranium mining operations be restored to pre-mining conditions. Reverse osmosis (RO) filtration of several pore volumes of the post-leached groundwater and reinjection of the clean permeate is the most common technology currently used for restoring groundwater at uranium ISR sites. However, this approach does not revert the formation back to its initial reducing conditions, which can potentially impede timely groundwater restoration. In-situ biostimulation of indigenous iron- and sulfate reducing bacteria by injection of organic electron donors (e.g., ethanol, acetate, and lactate) to promote soluble uranium reduction and immobilization has been the subject of previous studies. However, injection of organic substrates has been observed to cause aquifer clogging near the injection point. In addition, U(VI) solubility may be enhanced through complexation with carbonate generated by organic carbon oxidation. An alternative approach that may overcome these problems involves the use of hydrogen as a reductant to promote microbial reduction and immobilization of U(VI) in situ. To test this approach, approximately 100,000 scf of compressed hydrogen gas was injected into a leached unconsolidated sand zone over two months at an ISR mining site. During this time groundwater was recirculated between injection and extraction wells (separated by 130 ft) at a rate of about 40 gpm and bromide was coinjected as a conservative tracer. A well monitoring program has been executed since June 2009 to evaluate the performance of the hydrogen injection. Current results show that U(VI) has been reduced from 4.2 to 0.05 ppm in the area surrounding the injection well and to 2.0 ± 0.3 ppm in the area surrounding the extraction well and two intermediate monitoring wells. Other water quality changes near the injection well include significant decreases in concentrations of Mo, sulfate, Fe, Mn, bicarbonate, Ca

  8. Immobilization of Spirulina subsalsa for removal of triphenyltin from water.

    PubMed

    Huang, Guo-Lan; Zhihui, Song

    2002-07-01

    Spirulina subsalsa is immobilized with alginate, which increases the growth rate, chlorophyll content, phycocyanin content and nitrate reductase activity. Immobilized Spirulina subsalsa with alginate increases absorption of triphenyltin chloride (TPT). The phycocyanin of immobilized Spirulina subsalsa is more sensitive to TPT then free alga. The immobilization enhances the toxic effect of TPT on nitrate reductase activity of Spirulina subsalsa. Experimental results demonstrate that the immobilization of Spirulina subsalsa is feasible. Removal of TPT by immobilized Spirulina subsalsa reaches 68%. Biosorption mechanism of TPT by Spirulina subsalsa should be further studied.

  9. Carbon nanotubes as supports for inulinase immobilization.

    PubMed

    Garlet, Tais B; Weber, Caroline T; Klaic, Rodrigo; Foletto, Edson L; Jahn, Sergio L; Mazutti, Marcio A; Kuhn, Raquel C

    2014-09-15

    The commercial inulinase obtained from Aspergillus niger was non-covalently immobilized on multiwalled carbon nanotubes (MWNT-COOH). The immobilization conditions for the carbon nanotubes were defined by the central composite rotational design (CCRD). The effects of enzyme concentration (0.8%-1.7% v/v) and adsorbent:adsorbate ratio (1:460-1:175) on the enzyme immobilization were studied. The adsorbent:adsorbate ratio variable has positive effect and the enzyme concentration has a negative effect on the inulinase immobilization (U/g) response at the 90% significance level. These results show that the lower the enzyme concentration and the higher the adsorbent:adsorbate ratio, better is the immobilization. According to the results, it is possible to observe that the carbon nanotubes present an effective inulinase adsorption. Fast adsorption in about six minutes and a loading capacity of 51,047 U/g support using a 1.3% (v/v) inulinase concentration and a 1:460 adsorbent:adsorbate ratio was observed. The effects of temperature on the immobilized enzyme activity were evaluated, showing better activity at 50 °C. The immobilized enzyme maintained 100% of its activity during five weeks at room temperature. The immobilization strategy with MWNT-COOH was defined by the experimental design, showing that inulinase immobilization is a promising biotechnological application of carbon nanotubes.

  10. Study on the effect of sulphur, glucose, nitrogen and plant residues on the immobilization of sulphate-S in soil.

    PubMed

    Shahsavani, S

    2009-02-15

    In order to evaluate the relationship between sulphur (S), glucose (G), nitrogen (N) and plant residues (st), on sulphur immobilization and microbial transformation. Five soil samples from 0-30 cm of Bastam farmer's fields of Shahrood area were collected. Eleven treatments with different levels of S, G, N and plant residues (wheat straw) were applied in a randomized block design with three replications and incubated over 20, 45 and 60 days. The immobilization of SO4(-2)-S presented as a percentage of that added, was inversely related to its addition rate. Additions of glucose and plant residues increased with the C-to-S ratio of the added amendments, irrespective of their origins (glucose and plant residues). In the presence of C sources (glucose or plant residues). N significantly increased the immobilization of SO4(-2)-S, whilst the effect of N was insignificant in the absence of a C amendment. In first few days the amounts of added SO4(-2)-S immobilized were linearly correlated with the amounts of added S recovered in the soil microbial biomass. With further incubation the proportions of immobilized SO4(-2)-S remaining as biomass-S decreased. Decrease in biomass-S was thought to be due to the conversion ofbiomass-S into soil organic-S. Glucose addition increased the immobilization (microbial utilization and incorporation into the soil organic matter) of native soil SO4(-2)-S. However, N addition enhance the mineralization of soil organic-S, increasing the concentration of SO4(-2)-S in soil and the extent to which available-S can be immobilized is determined by both the amount of available-S and the availability of an utilizable C source.

  11. Exfoliated Egyptian kaolin immobilized heteropolyoxotungstate nanocomposite as an innovative antischistosomal agent: In vivo and in vitro bioactive studies.

    PubMed

    Bayaumy, Fatma E A; Darwish, Atef S

    2016-02-01

    This study aims to manipulate an antischistosomal nanocomposite based on exfoliated clay immobilized heteropolyoxotungstate. The nanocomposite's physicochemical characteristics were examined using XRD, Raman spectroscopy, FTIR, DLS, SEM, HR-TEM and AFM. Nano-sized spheroidal negatively charged Keggin-type heteropolyoxotungstate particles were developed along and between the exfoliated clay layers. The impact of the nanocomposite on Schistosoma mansoni-infected mice was studied through parasitological, physiological and histological analyses. Infected mice were orally vaccinated by a single nanocomposite dose (15mg/kg/day) for two weeks. The schistosomicidal activities of the nanocomposite in vitro were investigated by examining its dose- and time-dependent responses in terms of % worm mortality. The time-dependent morphological alterations in schistosomes at a nanocomposite dosage of 15μg/mL were followed by SEM. The nanocomposite exhibited potential schistosomicidal properties with a marked reduction in worm burden (~85% mortality), extensive deformities in the adult worm tegument and suckers, improvement of serum biochemical activities, and diminishment in granulomatous lesions. The in vitro release of heteropolyoxotungstate from exfoliated clay indicates the clay's ability to embrace the heteropolytungstate until its liberation at the parasitic districts.

  12. Protein selectivity with immobilized metal ion-tacn sorbents: chromatographic studies with human serum proteins and several other globular proteins.

    PubMed

    Jiang, W; Graham, B; Spiccia, L; Hearn, M T

    1998-01-01

    The chromatographic selectivity of the immobilized chelate system, 1,4,7-triazocyclononane (tacn), complexed with the borderline metal ions Cu2+, Cr3+, Mn2+, Co2+, Zn2+, and Ni2+ has been investigated with hen egg white lysozyme, horse heart cytochrome c, and horse skeletal muscle myoglobin, as well as proteins present in partially fractionated preparations of human plasma. The effects of ionic strength and pH of the loading and elution buffers on protein selectivities of these new immobilized metal ion affinity chromatographic (IMAC) systems have been examined. The results confirm that immobilized Mn;pl-tacn sorbents exhibit a novel type of IMAC behavior with proteins. In particular, the chromatographic properties of these immobilized M(n+)-tacn ligand systems were significantly different compared to the IMAC behavior observed with other types of immobilized tri- and tetradentate chelating ligands, such as iminodiacetic acid, O-phosphoserine, or nitrilotriacetic acid, when complexed with borderline metal ions. The experimental results have consequently been evaluated in terms of the additional contributions to the interactive processes mediated by effects other than solely the conventional lone pair Lewis soft acid-Lewis soft base coordination interactions, typically found for the IMAC of proteins with borderline and soft metal ions, such as Cu2+ or Ni2+.

  13. Screening of lipase inhibitors from Scutellaria baicalensis extract using lipase immobilized on magnetic nanoparticles and study on the inhibitory mechanism.

    PubMed

    Wan, Li-Hong; Jiang, Xiao-Lan; Liu, Yi-Ming; Hu, Jin-Jie; Liang, Jian; Liao, Xun

    2016-03-01

    Scutellaria baicalensis is a traditional Chinese medicinal plant possessing a wide variety of biological activities. In this work, lipase immobilized on magnetic nanoparticles (LMNPs) was used as solid phase extract absorbent for screening of lipase inhibitors from this plant. Three flavonoids were found to bind to LMNPs and were identified as baicalin, wogonin, and oroxylin A by liquid chromatography-mass spectrometry (HPLC-MS). Their IC50 values were determined to be 229.22 ± 12.67, 153.71 ± 9.21, and 56.07 ± 4.90 μM, respectively. Fluorescence spectroscopy and molecular docking were used to probe the interactions between these flavonoids and lipase. All the flavonoids quenched the fluorescence of lipase statically by forming new complexes, implying their affinities with the enzyme. The thermodynamic analysis suggested that van der Waals force and hydrogen bond were the main forces between wogonin and lipase, while hydrophobic force was the main force for the other two flavonoids. The results from a molecular docking study further revealed that all of them could insert into the pocket of lipase binding to a couple of amino acid residues.

  14. Microstructural and potential dependence studies of urease-immobilized gold nanoparticles-polypyrrole composite film for urea detection.

    PubMed

    Rajesh; Puri, Nidhi; Mishra, Sujeet K; Laskar, Mariam J; Srivastava, Avanish K

    2014-01-01

    Gold nanoparticle-polypyrrole nanocomposite film was electrochemically deposited in a single-step polymerization of pyrrole in the presence of 3-mercaptopropionic acid (MPA)-capped gold nanoparticles (GNPs) and p-toluenesulfonic acid (pTSA) on the surface of an indium tin oxide (ITO)-coated glass plate. The carboxyl functional groups surrounding the GNPs within the polymer matrix were utilized for the immobilization of urease enzyme through carbodiimide coupling reaction for the construction of a Urs/GNP(MPA)-PPy/ITO-glass bioelectrode for urea detection in Tris-HCl buffer. The resulting bioelectrode film was characterized by atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), contact angle measurement, Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The potentiometric response of the bioelectrode made of polymer nanocomposite films of two different thicknesses prepared at 100 and 250 mC cm(-2) charge densities, respectively, was studied towards the urea concentration in Tris-HCl buffer (pH 7.4). The thin polymer nanocomposite film-based bioelectrode prepared at 100 mC cm(-2) charge density exhibited a comparatively good potentiometric response than a thick 250 mC cm(-2) charge density film with a linear range of urea detection from 0.01 to 10 mM with a sensitivity of 29.7 mV per decade.

  15. Immobilization of bovine catalase onto magnetic nanoparticles.

    PubMed

    Doğaç, Yasemin İspirli; Teke, Mustafa

    2013-01-01

    The scope of this study is to achieve carrier-bound immobilization of catalase onto magnetic particles (Fe₃O₄ and Fe₂O₃NiO₂ · H₂O) to specify the optimum conditions of immobilization. Removal of H2O2 and the properties of immobilized sets were also investigated. To that end, adsorption and then cross-linking methods onto magnetic particles were performed. The optimum immobilization conditions were found for catalase: immobilization time (15 min for Fe₃O₄; 10 min for Fe2O₃NiO₂ · H₂O), the initial enzyme concentration (1 mg/mL), amount of magnetic particles (25 mg), and glutaraldehyde concentration (3%). The activity reaction conditions (optimum temperature, optimum pH, pH stability, thermal stability, operational stability, and reusability) were characterized. Also kinetic parameters were calculated by Lineweaver-Burk plots. The optimum pH values were found to be 7.0, 7.0, and 8.0 for free enzyme, Fe₃O₄-immobilized catalases, and Fe₂O₃NiO₂ · H₂O-immobilized catalases, respectively. All immobilized catalase systems displayed the optimum temperature between 25 and 35°C. Reusability studies showed that Fe₃O₄-immobilized catalase can be used 11 times with 50% loss in original activity, while Fe2O₃NiO₂ · H₂O-immobilized catalase lost 67% of activity after the same number of uses. Furthermore, immobilized catalase systems exhibited improved thermal and pH stability. The results transparently indicate that it is possible to have binding between enzyme and magnetic nanoparticles.

  16. Study of whey fermentation by kefir immobilized on low cost supports using 14C-labelled lactose.

    PubMed

    Soupioni, Magdalini; Golfinopoulos, Aristidis; Kanellaki, Maria; Koutinas, Athanasios A

    2013-10-01

    Brewer's Spent Grains (BSG) and Malt Spent Rootlets (MSR) were used as supports for kefir cells immobilization and the role of lactose uptake rate by kefir in the positive activity of produced biocatalysts during whey fermentation was investigated. Lactose uptake rate by the immobilized cells was recorded using (14)C-labelled lactose and the effect of various conditions (pH, temperature and kind of support) on it and consequently on fermentation time and ethanol production was examined. The results showed that lactose uptake rate was correlated to fermentation rate and increased as temperature was increased up to 30°C at pH 5.5. The same results have been recently noticed by using biocatalysts with Delignified Cellulosic Materials (DCM) and Gluten Pellets (GP), but fermentation time of about 7h by kefir immobilized on DCM and BSG resulted to two fold lower than that on GP and MSR. The highest alcohol concentration was observed by MSR.

  17. Immobilization of cholesterol oxidase on cellulose acetate membrane for free cholesterol biosensor development.

    PubMed

    Wang, Shenqi; Li, Shipu; Yu, Yaoting

    2004-01-01

    This article describes the immobilization of cholesterol oxidase on a cellulose acetate (CA) membrane activated by Sodium periodate, ethylenediamine, and glutaraldehyde etc. The properties of the immobilized enzyme membrane were investigated. The factors affecting the activity of immobilized enzyme such as the concentration of glutaraldehyde, the concentration of enzyme used during immobilization, temperature, pH, and immobilizing time etc. were also studied. The immobilized COD membrane has been used to construct fibre-optic fluorescent biosensor.

  18. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    DOE PAGES

    Shaw, Wendy J.

    2014-10-29

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin and leucine rich amelogenin protein (LRAP), have been studied in depth and have different features, challenging our ability to extract design principles. More recent studies of the significantly larger full-length amelogenin represent a challenging but necessary step to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids and silaffin peptide with silica are also being studied, along with qualitative studies of proteins interacting with calcium carbonate. Dipolar recoupling techniquesmore » have formed the core of the quantitative studies, yet, the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques is advancing, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area.« less

  19. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    SciTech Connect

    Shaw, Wendy J.

    2014-10-29

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin and leucine rich amelogenin protein (LRAP), have been studied in depth and have different features, challenging our ability to extract design principles. More recent studies of the significantly larger full-length amelogenin represent a challenging but necessary step to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids and silaffin peptide with silica are also being studied, along with qualitative studies of proteins interacting with calcium carbonate. Dipolar recoupling techniques have formed the core of the quantitative studies, yet, the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques is advancing, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area.

  20. Ultra-small rhenium nanoparticles immobilized on DNA scaffolds: An excellent material for surface enhanced Raman scattering and catalysis studies.

    PubMed

    Anantharaj, S; Sakthikumar, K; Elangovan, Ayyapan; Ravi, G; Karthik, T; Kundu, Subrata

    2016-12-01

    Highly Sensitive and ultra-small Rhenium (Re) metal nanoparticles (NPs) were successfully stabilized in water by the staging and fencing action of the versatile biomolecule DNA that resulted in two distinct aggregated chain-like morphologies with average grain sizes of 1.1±0.1nm and 0.7±0.1nm for the very first time within a minute of reaction time. Re NPs are formed by the borohydride reduction of ammonium perrhenate (NH4ReO4) in the presence of DNA at room temperature (RT) under stirring. The morphologies were controlled by carefully monitoring the molar ratio of NH4ReO4 and DNA. The synthesized material was employed in two potential applications: as a substrate for surface enhanced Raman scattering (SERS) studies and as a catalyst for the reduction of aromatic nitro compounds. SERS study was carried out by taking methylene blue (MB) as the probe and the highest SERS enhancement factor (EF) of 2.07×10(7) was found for the aggregated chain-like having average grain size of 0.7±0.1nm. Catalytic reduction of 4-nitro phenol (4-NP), 2-nitro phenol (2-NP) and 4-nitroaniline (4-NA) with a rate constant value of 6×10(-2)min(-1), 33.83×10(-2)min(-1) and 37.4×10(-2)min(-1) have testified the excellent catalytic performance of our Re NPs immobilized on DNA. The overall study have revealed the capability of DNA in stabilizing the highly reactive Re metal at nanoscale and made them applicable in practice. The present route can also be extended to prepare one dimensional (1-D), self-assembled NPs of other reactive metals, mixed metals or even metal oxides for specific applications in water based solutions.

  1. Penetrable silica microspheres for immobilization of bovine serum albumin and their application to the study of the interaction between imatinib mesylate and protein by frontal affinity chromatography.

    PubMed

    Ma, Liyun; Li, Jing; Zhao, Juan; Liao, Han; Xu, Li; Shi, Zhi-guo

    2016-01-01

    In the current study, novel featured silica, named penetrable silica, simultaneously containing macropores and mesopores, was immobilized with bovine serum albumin (BSA) via Schiff base method. The obtained BSA-SiO2 was employed as the high-performance liquid chromatographic (HPLC) stationary phase. Firstly, D- and L-tryptophan were used as probes to investigate the chiral separation ability of the BSA-SiO2 stationary phase. An excellent enantioseparation factor was obtained up to 4.3 with acceptable stability within at least 1 month. Next, the BSA-SiO2 stationary phase was applied to study the interaction between imatinib mesylate (IM) and BSA by frontal affinity chromatography. A single type of binding site was found for IM with the immobilized BSA, and the hydrogen-bonding and van der Waals interactions were expected to be contributing interactions based on the thermodynamic studies, and this was a spontaneous process. Compared to the traditional silica for HPLC stationary phase, the proposed penetrable silica microsphere possessed a larger capacity to bond more BSA, minimizing column overloading effects and enhancing enantioseparation ability. In addition, the lower running column back pressure and fast mass transfer were meaningful for the column stability and lifetime. It was a good substrate to immobilize biomolecules for fast chiral resolution and screening drug-protein interactions.

  2. Zinc Oxide Nanoparticles Supported Lipase Immobilization for Biotransformation in Organic Solvents: A Facile Synthesis of Geranyl Acetate, Effect of Operative Variables and Kinetic Study.

    PubMed

    Patel, Vrutika; Shah, Chandani; Deshpande, Milind; Madamwar, Datta

    2016-04-01

    The present study describes grafting of zinc oxide (ZnO) nanoparticles with polyethyleneimine (PEI) followed by modification with glutraldehyde used as the bridge for binding the enzyme to support. The prepared nanocomposites were then characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy, utilized for synthesis of geranyl acetate in n-hexane. Among all the three prepared nanocomposites (ZnO + PEI, ZnO + PEI + SAA, ZnO + PEI + GLU), Candida rugosa lipase immobilized on ZnO-PEI-GLU was found to be best for higher ester synthesis. The operating conditions that maximized geranyl acetate resulted in the highest yield of 94 % in 6 h, molar ratio of 0.1:0.4 M (geraniol/vinyl acetate) in the presence of n-hexane as reaction medium. Various kinetic parameters such as V max, K i(G), K m(G), and K m(VA) were determined using nonlinear regression analysis for order bi-bi mechanism. The kinetic study showed that reaction followed order bi-bi mechanism with inhibition by geraniol. Activation energy (E a ) was found to be lower for immobilized lipase (12.31 kJ mol(-1)) than crude lipase (19.04 kJ mol(-1)) indicating better catalytic efficiency of immobilized lipase. Immobilized biocatalyst demonstrated 2.23-fold increased catalytic activity than crude lipase and recycled 20 times. The studies revealed in this work showed a promising perspective of using low-cost nanobiocatalysts to overcome the well-known drawbacks of the chemical-catalyzed route.

  3. Continuous monitoring of enzymatic reactions on surfaces by real-time flow cytometry: sortase a catalyzed protein immobilization as a case study.

    PubMed

    Heck, Tobias; Pham, Phu-Huy; Hammes, Frederik; Thöny-Meyer, Linda; Richter, Michael

    2014-08-20

    Only a few techniques, such as quartz crystal microbalance and surface plasmon resonance spectroscopy, enable the analysis of dynamic processes on solid supports. Here we have developed a straightforward assay based on flow cytometry to continuously follow enzymatic reactions directly on microparticle surfaces. We applied this real-time flow cytometry (RT-FCM) approach to study the covalent immobilization of green-fluorescent protein (GFPuv) on triglycine-modified polystyrene microbeads by the transpeptidase sortase A (SrtA) from Staphylococcus aureus. Though commonly treated as functionally identical catalysts, the SrtA variants SrtAΔ₅₉ and SrtAΔ₂₅, in which the N-terminal amino acid residues 1-59 and 1-25 of the native enzyme are truncated, were shown to perform very differently with regard to this particular immobilization reaction. While SrtAΔ₅₉ efficiently catalyzed the covalent attachment of GFPuv to the surface (as indicated by a linear increase of microbead fluorescence), SrtAΔ₂₅ was essentially inactive. Besides the length of the N-terminal amino acid extension on the SrtA construct, the position of the hexahistidine tag at either the N- or C-terminus affected the efficiency of enzymatic protein immobilization. Apart from three enzyme variants containing the native core structure of SrtA, we also included three recently evolved mutants of SrtA in this comparative study. With these mutants we observed a rapid initial attachment of the GFPuv target protein to the microbeads. However, with proceeding reaction time, cleavage of the covalently immobilized target protein from the surface prevailed over the coupling reaction, consequently causing a decline of microbead fluorescence. In general, the RT-FCM approach used herein represents a powerful analytical tool for qualitative dynamic studies of many heterogeneous enzymatic reactions or other binding events that influence the fluorescence properties of microparticle surfaces.

  4. Results of an inter-laboratory study of glass formulation for the immobilization of excess plutonium

    SciTech Connect

    Peeler, D.K.

    1999-12-08

    The primary focus of the current study is to determine allowable loadings of feed streams containing different ratios of plutonium, uranium, and minor components into the LaBS glass and to evaluate thermal stability with respect to the DWPF pour.

  5. Immobilization of cobalt(II) Schiff base complexes on polystyrene resin and a study of their catalytic activity for the aerobic oxidation of alcohols.

    PubMed

    Jain, Suman; Reiser, Oliver

    2008-01-01

    The copper-catalyzed [3+2] azide-alkyne cycloaddition and the Staudinger ligation are readily applicable and highly efficient for the immobilization of cobalt Schiff base complexes onto polystyrene resins. Stepwise synthesis of polymer-bound Schiff bases followed by their subsequent complexation with metal ions were successfully carried out. Direct covalent attachment of preformed homogeneous cobalt Schiff base complexes to the resins was also possible. The catalytic efficiency of the so-prepared polystyrene-bound cobalt Schiff bases was studied for the oxidation of alcohols to carbonyl compounds using molecular oxygen as oxidant. The immobilized complexes were highly efficient and even more reactive than the corresponding homogenous analogues, thus affording better yields of oxidized products within shorter reaction times. The supported catalysts could easily be recovered from the reaction mixture by simple filtration and reused for subsequent experiments with consistent catalytic activity.

  6. A comparative study of immobilization techniques for urease on glass-pH-electrode and its application in urea detection in blood serum.

    PubMed

    Sahney, Rachana; Anand, S; Puri, B K; Srivastava, A K

    2006-09-25

    Different techniques have been used (physical adsorption, physically entrapped sandwich and microencapsulation) for the immobilization of urease enzyme in tetramethylorthosilicate (TMOS) derived sol-gel matrix on the sensing surface of glass-pH-electrode. No significant leaching of enzyme occurs from the microencapsulated and physically entrapped enzyme sandwich films. Potentiometric techniques have been used for the estimation of urea concentration in each instance. Various parameters of biosensor performance have been studied which indicates that microencapsulation technique is a better method of enzyme immobilization in sol-gel films derived from TMOS. The advantage of microencapsulated biosensor over others include higher sensitivity (dpH/dp(C)=2.4), lower detection limit of 52 microg mL(-1), larger linear range (0.01-30 mM) of urea determination and reasonably long-term stability of about 25 days with 80% response signal.

  7. An enzyme immobilized microassay in capillary electrophoresis for characterization and inhibition studies of alkaline phosphatases.

    PubMed

    Iqbal, Jamshed

    2011-07-15

    A simple and fast dynamically coated capillary electrophoretic method was developed for the characterization and inhibition studies of alkaline phosphatases(EC 3.1.3.1). An inside capillary enzymatic reaction was performed, and hydrolysis of the substrate 4-nitrophenylphosphate to 4-nitrophenol was measured. Fused-silica capillary surface was dynamically modified with polycationic polybrene coating. By reversal of the electroosmotic flow (EOF), analysis time was reduced up to 3 min as the anionic analytes were migrated in the same direction as the EOF. Furthermore, the sensitivity of the method was increased using electroinjection through high-field amplified injection. The baseline separation of 4-nitrophenylphosphate and 4-nitrophenol was achieved by employing 50 mM sodium phosphate as the running buffer (pH 8.5), 0.0025% polybrene, and a constant voltage of -15 kV, and the products were detected at 322 nm. Under the optimized conditions, a good separation with high efficiency was achieved. The new method was applied to study enzyme kinetics and inhibitor screening. K(m) and K(i) values obtained with the new CE method were compared well with the standard spectrophotometric method. Dynamic coating of fused-silica capillary gave fast and reproducible separation of substrate and product. The method can be easily optimized for inhibition studies of other isozymes.

  8. Trichloroethylene aerobic cometabolism by suspended and immobilized butane-growing microbial consortia: a kinetic study.

    PubMed

    Frascari, Dario; Zanaroli, Giulio; Bucchi, Giacomo; Rosato, Antonella; Tavanaie, Nasrin; Fraraccio, Serena; Pinelli, Davide; Fava, Fabio

    2013-09-01

    A kinetic study of butane uptake and trichloroethylene (TCE) aerobic cometabolism was conducted by two suspended-cell (15 and 30°C) and two attached-cell (15 and 30°C) consortia obtained from the indigenous biomass of a TCE-contaminated aquifer. The shift from suspended to attached cells resulted in an increase of butane (15 and 30°C) and TCE (15°C) biodegradation rates, and a significant decrease of butane inhibition on TCE biodegradation. The TCE 15°C maximum specific biodegradation rate was equal to 0.011 mg(TCE ) mg(protein)(-1) d(-1) with suspended cells and 0.021 mg(TCE) mg(protein)(-1) d(-1) with attached cells. The type of mutual butane/TCE inhibition depended on temperature and biomass conditions. On the basis of a continuous-flow simulation, a packed-bed PFR inoculated with the 15 or 30°C attached-cell consortium could attain a 99.96% conversion of the studied site's average TCE concentration with a 0.4-0.5-day hydraulic residence time, with a low effect of temperature on the TCE degradation performances.

  9. Pinning of the Contact Line during Evaporation on Heterogeneous Surfaces: Slowdown or Temporary Immobilization? Insights from a Nanoscale Study.

    PubMed

    Zhang, Jianguo; Müller-Plathe, Florian; Leroy, Frédéric

    2015-07-14

    The question of the effect of surface heterogeneities on the evaporation of liquid droplets from solid surfaces is addressed through nonequilibrium molecular dynamics simulations. The mechanism behind contact line pinning which is still unclear is discussed in detail on the nanoscale. Model systems with the Lennard-Jones interaction potential were employed to study the evaporation of nanometer-sized cylindrical droplets from a flat surface. The heterogeneity of the surface was modeled through alternating stripes of equal width but two chemical types. The first type leads to a contact angle of 67°, and the other leads to a contact angle of 115°. The stripe width was varied between 2 and 20 liquid-particle diameters. On the surface with the narrowest stripes, evaporation occurred at constant contact angle as if the surface was homogeneous, with a value of the contact angle as predicted by the regular Cassie-Baxter equation. When the width was increased, the contact angle oscillated during evaporation between two boundaries whose values depend on the stripe width. The evaporation behavior was thus found to be a direct signature of the typical size of the surface heterogeneity domains. The contact angle both at equilibrium and during evaporation could be predicted from a local Cassie-Baxter equation in which the surface composition within a distance of seven fluid-particle diameters around the contact line was considered, confirming the local nature of the interactions that drive the wetting behavior of droplets. More importantly, we propose a nanoscale explanation of pinning during evaporation. Pinning should be interpreted as a drastic slowdown of the contact line dynamics rather than a complete immobilization of it during a transition between two contact angle boundaries.

  10. A kinetic study of bitter taste receptor sensing using immobilized porcine taste bud tissues.

    PubMed

    Wei, Lihui; Qiao, Lixin; Pang, Guangchang; Xie, Junbo

    2017-06-15

    At present, developing an efficient assay method for truly reflecting the real feelings of gustatory tissues is of great importance. In this study, a novel biosensor was fabricated to investigate the kinetic characteristics of the receptors in taste bud tissues sensing bitter substances for the first time. Porcine taste bud tissues were used as the sensing elements, and the sandwich-type sensing membrane was fixed onto a glassy carbon electrode for assembling the biosensor. With the developed sensor, the response currents induced by sucrose octaacetate, denatonium benzoate, and quercetin stimulating corresponding receptors were determined. The results demonstrated that the interaction between the analyst with their receptors were fitting to hyperbola (R(2)=0.9776, 0.9980 and 0.9601), and the activation constants were 8.748×10(-15)mol/L, 1.429×10(-12)mol/L, 6.613×10(-14)mol/L, respectively. The average number of receptors per cell was calculated as 1.75, 28.58, and 13.23, while the signal amplification factors were 1.08×10(4), 2.89×10(3) and 9.76×10(4). These suggest that the sensor can be used to quantitatively describe the interaction characteristics of cells or tissue receptors with their ligands, the role of cellular signaling cascade, the number of receptors, and the signal transmission pathways.

  11. A nanoparticle-based immobilization assay for prion-kinetics study

    PubMed Central

    Kouassi, Gilles K; Irudayaraj, Joseph

    2006-01-01

    Magnetic and gold coated magnetic nanoparticles were synthesized by co-precipitation of ferrous and ferric chlorides, and by the micromicelles method, respectively. Synthesized nanoparticles were functionalized to bear carboxyl and amino acid moieties and used as prion protein carriers after carbodiimide activation in the presence of N-hydroxysuccinimide. The binding of human recombinant prion protein (huPrPrec) to the surface of these nanoparticles was confirmed by FTIR and the size and structures of the particles were characterized by transmission electron microscopy. Findings indicate that the rate of prion binding increased only slightly when the concentration of prion in the reaction medium was increased. Rate constants of binding were very similar on Fe3O4@Au and Fe3O4-LAA when the concentrations of protein were 1, 2, 1.5, 2.25 and 3.57 μg/ml. For a 5 μg/ml concentration of huPrPrec the binding rate constant was higher for the Fe3O4-LAA particles. This study paves the way towards the formation of prion protein complexes onto a 3-dimensional structure that could reveal obscure physiological and pathological structure and prion protein kinetics. PMID:16916458

  12. An electrochemical quartz crystal impedance study on anti-human immunoglobulin G immobilization in the polymer grown during dopamine oxidation at an Au electrode.

    PubMed

    He, Hua; Xie, Qingji; Yao, Shouzhuo

    2005-09-15

    The polymeric film grown during dopamine oxidation at an Au electrode was studied as a novel matrix for immobilizing anti-human immunoglobulin G (IgG) via the electrochemical quartz crystal impedance analysis (EQCIA) method. The growth of the polymeric films at Au electrodes during dopamine oxidation in neutral phosphate buffer (pH 7.4) and the immobilization of anti-human IgG into the polymeric films during their growth have been traced at real time. Lysozyme control experiments suggested that anti-human IgG was electrostatically incorporated into the polymeric film. Also, the porosity of the polymeric films has been discussed by measuring the "wet" and "dry" frequency shifts. Compared with a polypyrrole film immobilized with anti-human IgG, the proposed matrix possessed a larger amount of specific binding sites for human IgG by subsequent immunoreaction tests. The association constant of the anti-human IgG immunoreaction was obtained with satisfactory results.

  13. Study on the immobilization of anti-IgG on Au-colloid modified gold electrode via potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques.

    PubMed

    Fu, Yingzi; Yuan, Ruo; Tang, Dianping; Chai, Yaqin; Xu, Lan

    2005-01-15

    The immobilization of anti-IgG on Au-colloid modified gold electrodes has been investigated. A cleaned gold electrode was first immersed in a mercaptoethylamine (AET) solution, and then gold nanoparticles were chemisorbed onto the thiol groups of the mercaptoethylamine. Finally, anti-IgG was adsorbed onto the surface of the gold nanoparticles. Potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques were used to investigate the immobilization of anti-IgG on Au colloids. In the impedance spectroscopic study, an obvious difference of the electron transfer resistance between the Au-colloid modified electrode and the bare gold electrode was observed. The cyclic voltammogram tends to be more irreversible with increased anti-IgG concentration. Using the potentiometric immunosensor, the proposed technique is based on that the specific agglutination of antibody-coated gold nanoparticles, averaging 16 nm in diameter, in the presence of the corresponding antigen causes a potential change that is monitored by a potentiometry. It is found that the developed immunoagglutination assay system is sensitive to the concentration of IgG antigen as low as 12 ng mL(-1). Experimental results showed that the developed technique is in satisfactory agreement with the ELISA method, and that gold nanoparticles can be used as a biocompatible matrix for antibody or antigen immobilization.

  14. [Pathophysiology of immobilization osteoporosis.

    PubMed

    Menuki, Kunitaka; Sakai, Akinori

    Enhancement of bone resorption and suppression of bone formation in response to reduced mechanical stress cause rapid bone loss. pharmacotherapy for immobilization osteoporosis in motor paralysis and long-term bedrest is effective therapy. Early intervention for rapid bone loss is important for immobilization osteoporosis.

  15. Immobilization of excess weapons plutonium in Russia

    SciTech Connect

    Borisov, G B; Jardine, L J; Mansourov, O A

    1999-01-25

    In this paper, we examine the logic and framework for the development of a capability to immobilize excess Russian weapons plutonium by the year 2004. The initial activities underway in Russia, summarized here, include engineering feasibility studies of the immobilization of plutonium-containing materials at the Krasnoyarsk and Mayak industrial sites. In addition, research and development (R&D) studies are underway at Russian institutes to develop glass and ceramic forms suitable for the immobilization of plutonium-containing materials, residues, and wastes and for their geologic disposal.

  16. Waste/soil treatability studies for four complex industrial wastes: methodologies and results. Volume 2. Waste loading impacts on soil degradation, transformation, and immobilization. Final report

    SciTech Connect

    Sims, R.C.; Sorensen, D.L.; Doucette, W.J.; Hastings, L.L.; Sims, J.L.

    1986-10-01

    The two-volume report presents information pertaining to quantitative evaluation of the soil-treatment potential resulting from waste-soil interaction studies for four specific wastes listed under Section 3001 of the Resource Conservation and Recovery Act. Volume 2 contains results from bench-scale waste-soil interaction studies; degradation, transformation, and immobilization data are presented for four specific wastes: API separator sludge, slop oil emulsion solids, pentachlorophenol wood preserving waste, and creosote wood-preserving waste. The scope of the study involved assessment of the potential for treatment of these hazardous wastes using soil as the treatment medium.

  17. Plutonium Disposition by Immobilization

    SciTech Connect

    Gould, T.; DiSabatino, A.; Mitchell, M.

    2000-03-07

    The ultimate goal of the Department of Energy (DOE) Immobilization Project is to develop, construct, and operate facilities that will immobilize between 17 to 50 tonnes (MT) of U.S. surplus weapons-usable plutonium materials in waste forms that meet the ''spent fuel'' standard and are acceptable for disposal in a geologic repository. Using the ceramic can-in-canister technology selected for immobilization, surplus plutonium materials will be chemically combined into ceramic forms which will be encapsulated within large canisters of high level waste (HLW) glass. Deployment of the immobilization capability should occur by 2008 and be completed within 10 years. In support of this goal, the DOE Office of Fissile Materials Disposition (MD) is conducting development and testing (D&T) activities at four DOE laboratories under the technical leadership of Lawrence Livermore National Laboratory (LLNL). The Savannah River Site has been selected as the site for the planned Plutonium Immobilization Plant (PIP). The D&T effort, now in its third year, will establish the technical bases for the design, construction, and operation of the U. S. capability to immobilize surplus plutonium in a suitable and cost-effective manner. Based on the D&T effort and on the development of a conceptual design of the PIP, automation is expected to play a key role in the design and operation of the Immobilization Plant. Automation and remote handling are needed to achieve required dose reduction and to enhance operational efficiency.

  18. Immobilization of Peroxidase onto Magnetite Modified Polyaniline

    PubMed Central

    Barbosa, Eduardo Fernandes; Molina, Fernando Javier; Lopes, Flavio Marques; García-Ruíz, Pedro Antonio; Caramori, Samantha Salomão; Fernandes, Kátia Flávia

    2012-01-01

    The present study describes the immobilization of horseradish peroxidase (HRP) on magnetite-modified polyaniline (PANImG) activated with glutaraldehyde. After the optimization of the methodology, the immobilization of HRP on PANImG produced the same yield (25%) obtained for PANIG with an efficiency of 100% (active protein). The optimum pH for immobilization was displaced by the effect of the partition of protons produced in the microenvironment by the magnetite. The tests of repeated use have shown that PANImG-HRP can be used for 13 cycles with maintenance of 50% of the initial activity. PMID:22489198

  19. Effectiveness of olive oil for the prevention of pressure ulcers caused in immobilized patients within the scope of primary health care: study protocol for a randomized controlled trial

    PubMed Central

    2013-01-01

    Background Pressure ulcers are considered an important issue, mainly affecting immobilized older patients. These pressure ulcers increase the care burden for the professional health service staff as well as pharmaceutical expenditure. There are a number of studies on the effectiveness of different products used for the prevention of pressure ulcers; however, most of these studies were carried out at a hospital level, basically using hyperoxygenated fatty acids (HOFA). There are no studies focused specifically on the use of olive-oil-based products and therefore this research is intended to find the most cost-effective treatment and achieve an alternative treatment. Methods/design The main objective is to assess the effectiveness of olive oil, comparing it with HOFA, to treat immobilized patients at home who are at risk of pressure ulcers. As a secondary objective, the cost-effectiveness balance of this new application with regard to the HOFA will be assessed. The study is designed as a noninferiority, triple-blinded, parallel, multi-center, randomized clinical trial. The scope of the study is the population attending primary health centers in Andalucía (Spain) in the regional areas of Malaga, Granada, Seville, and Cadiz. Immobilized patients at risk of pressure ulcers will be targeted. The target group will be treated by application of an olive-oil-based formula whereas the control group will be treated by application of HOFA to the control group. The follow-up period will be 16 weeks. The main variable will be the presence of pressure ulcers in the patient. Secondary variables include sociodemographic and clinical information, caregiver information, and whether technical support exists. Statistical analysis will include the Kolmogorov-Smirnov test, symmetry and kurtosis analysis, bivariate analysis using the Student’s t and chi-squared tests as well as the Wilcoxon and the Man-Whitney U tests, ANOVA and multivariate logistic regression analysis. Discussion The

  20. Diffusion of solutes inside bacterial colonies immobilized in model cheese depends on their physicochemical properties: a time-lapse microscopy study

    PubMed Central

    Floury, Juliane; El Mourdi, Ilham; Silva, Juliana V. C.; Lortal, Sylvie; Thierry, Anne; Jeanson, Sophie

    2015-01-01

    During cheese processing and ripening, bacteria develop as colonies. Substrates and metabolites must then diffuse either from or into the colonies. Exploring how the inner cells of the colony access the substrates or get rid of the products leads to study the diffusion of solutes inside bacterial colonies immobilized in cheese. Diffusion limitations of substrates within the bacterial colony could lead to starvation for the cells in the center of the colony. This study aimed at better understands ripening at the colony level, by investigating how diffusion phenomena inside colonies vary depending on both the physicochemical properties of the solutes and Lactococcus lactis strain. Dextrans (4, 70, and 155 kDa) and milk proteins (BSA, lactoferrin and αS1-casein) of different sizes and physicochemical properties were chosen as model of diffusing solutes, and two L. lactis strains presenting different surface properties were immobilized as colonies in a model cheese. Diffusion of solutes inside and around colonies was experimentally followed by time-lapse confocal microscopy. Dextran solutes diffused inside both lactococci colonies with a non-significantly different effective diffusion coefficient, which depended mainly on size of the solute. However, whereas flexible and neutral hydrophilic polymers such as dextran can diffuse inside colonies whatever its size, none of the three proteins investigated in this study could penetrate inside lactococci colonies. Therefore, the diffusion behavior of macromolecules through bacterial colonies immobilized in a model cheese did not only depends on the size of the diffusing solutes, but also and mainly on their physicochemical properties. Milk caseins are probably first hydrolyzed by the cell wall proteases of L. lactis and/or other proteases present in the cheese, and then the generated peptides diffuse inside colonies to be further metabolized into smaller peptides and amino acids by all the cells located inside the colonies

  1. Immobilization induced hypercalcemia

    PubMed Central

    Cano-Torres, Edgar Alonso; González-Cantú, Arnulfo; Hinojosa-Garza, Gabriela; Castilleja-Leal, Fernando

    2016-01-01

    Summary Immobilization hypercalcemia is an uncommon diagnosis associated with increased bone remodeling disorders and conditions associated with limited movement such as medullar lesions or vascular events. Diagnosis requires an extensive evaluation to rule out other causes of hypercalcemia. This is a report of a woman with prolonged immobilization who presented with severe hypercalcemia. This case contributes to identification of severe hypercalcemia as a result of immobility and the description of bone metabolism during this state. PMID:27252745

  2. Study of the potential of the air lift bioreactor for xylitol production in fed-batch cultures by Debaryomyces hansenii immobilized in alginate beads.

    PubMed

    Pérez-Bibbins, Belinda; de Souza Oliveira, Ricardo Pinheiro; Torrado, Ana; Aguilar-Uscanga, María Guadalupe; Domínguez, José Manuel

    2014-01-01

    Cell immobilization has shown to be especially adequate for xylitol production. This work studies the suitability of the air lift bioreactor for xylitol production by Debaryomyces hansenii immobilized in Ca-alginate operating in fed-batch cultures to avoid substrate inhibition. The results showed that the air lift bioreactor is an adequate system since the minimum air flow required for fluidization was even lower than that leading to the microaerobic conditions that trigger xylitol accumulation by this yeast, also maintaining the integrity of the alginate beads and the viability of the immobilized cells until 3 months of reuses. Maximum productivities and yields of 0.43 g/l/h and 0.71 g/g were achieved with a xylose concentration of 60 g/l after each feeding. The xylose feeding rate, the air flow, and the biomass concentration at the beginning of the fed-batch operation have shown to be critical parameters for achieving high productivities and yields. Although a maximum xylitol production of 139 g/l was obtained, product inhibition was evidenced in batch experiments, which allowed estimating at 200 and 275 g/l the IC50 for xylitol productivity and yield, respectively. The remarkable production of glycerol in the absence of glucose was noticeable, which could not only be attributed to the osmoregulatory function of this polyol in conditions of high osmotic pressure caused by high xylitol concentrations but also to the role of the glycerol synthesis pathway in the regeneration of NAD(+) in conditions of suboptimal microaeration caused by insufficient aeration or high oxygen demand when high biomass concentrations were achieved.

  3. Effect of fermentation parameters on bio-alcohols production from glycerol using immobilized Clostridium pasteurianum: an optimization study.

    PubMed

    Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

    2013-01-01

    This article addresses the issue of effect of fermentation parameters for conversion of glycerol (in both pure and crude form) into three value-added products, namely, ethanol, butanol, and 1,3-propanediol (1,3-PDO), by immobilized Clostridium pasteurianum and thereby addresses the statistical optimization of this process. The analysis of effect of different process parameters such as agitation rate, fermentation temperature, medium pH, and initial glycerol concentration indicated that medium pH was the most critical factor for total alcohols production in case of pure glycerol as fermentation substrate. On the other hand, initial glycerol concentration was the most significant factor for fermentation with crude glycerol. An interesting observation was that the optimized set of fermentation parameters was found to be independent of the type of glycerol (either pure or crude) used. At optimum conditions of agitation rate (200 rpm), initial glycerol concentration (25 g/L), fermentation temperature (30°C), and medium pH (7.0), the total alcohols production was almost equal in anaerobic shake flasks and 2-L bioreactor. This essentially means that at optimum process parameters, the scale of operation does not affect the output of the process. The immobilized cells could be reused for multiple cycles for both pure and crude glycerol fermentation.

  4. Equilibrium isotherm and kinetic studies for the simultaneous removal of phenol and cyanide by use of S. odorifera (MTCC 5700) immobilized on coconut shell activated carbon

    NASA Astrophysics Data System (ADS)

    Singh, Neetu; Balomajumder, Chandrajit

    2016-09-01

    In this study, simultaneous removal of phenol and cyanide by a microorganism S. odorifera (MTCC 5700) immobilized onto coconut shell activated carbon surface (CSAC) was studied in batch reactor from mono and binary component aqueous solution. Activated carbon was derived from coconut shell by chemical activation method. Ferric chloride (Fecl3), used as surface modification agents was applied to biomass. Optimum biosorption conditions were obtained as a function of biosorbent dosage, pH, temperature, contact time and initial phenol and cyanide concentration. To define the equilibrium isotherms, experimental data were analyzed by five mono component isotherm and six binary component isotherm models. The higher uptake capacity of phenol and cyanide onto CSAC biosorbent surface was 450.02 and 2.58 mg/g, respectively. Nonlinear regression analysis was used for determining the best fit model on the basis of error functions and also for calculating the parameters involved in kinetic and isotherm models. The kinetic study results revealed that Fractal-like mixed first second order model and Brouser-Weron-Sototlongo models for phenol and cyanide were capable to offer accurate explanation of biosorption kinetic. According to the experimental data results, CSAC with immobilization of bacterium S. odorifera (MTCC 5700) seems to be an alternative and effective biosorbent for the elimination of phenol and cyanide from binary component aqueous solution.

  5. (Immobilization of radioactive wastes)

    SciTech Connect

    Dole, L.R.

    1986-12-18

    The traveler participated as the co-chairman of the France/US Workshop in Cadarache, France, on the immobilization of radioactive wastes in cement-based materials. These meetings and site visits were conducted under the bilateral exchange agreement between the US-DOE and the Commissariate a l'Energie Atomique (CEA-France). Visits in France included the Cadarache, Valduc, Saclay, and Fontenay-aux-Roses Nuclear Research Centers. As a result of these discussions, an exchange of scientists between Saclay and ORNL was proposed. The traveler continued on to the FRG to visit a hazardous waste site remedial action project in Sprendlingen and the nuclear research and production facilities at the Karlsruhe Kernforschungszentrum (KfK) and the Alkem/Nukem/Transnuklear facilities at Hanau. Visits in the FRG were under the bilateral exchange agreement between the US-DOE and the Bundes Ministerium fur Forschung und Technologie (BMFT). The FRG supplied the traveler data on studies of super-compaction volume reduction efficiencies by KfK and Nukem. Also, Transnuklear is considering contributing two of their larger Konrad-certified packages to the MDU studies at ORNL. 1 tab.

  6. Ultra-low field T1 vs. T1rho at 3T and 7T: study of rotationally immobilized protein gels and animal brain tissues

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Inglis, Ben; Barr, Ian; Clarke, John

    2015-03-01

    Clinical magnetic resonance imaging (MRI) machines operating in static fields of typically 1.5 T or 3 T can capture information on slow molecular dynamics utilizing the so-called T1rho technique. This technique, in which a radiofrequency (RF) spin-lock field is applied with microtesla amplitude, has been used, for example, to determine the onset time of stroke in studies on rats. The long RF pulse, however, may exceed the specific absorption rate (SAR) limit, putting subjects at risk. Ultra-low-field (ULF) MRI, based on Superconducting Quantum Interference Devices (SQUIDs), directly detects proton signals at a static magnetic field of typically 50-250 μT. Using our ULF MRI system with adjustable static field of typically 55 to 240 μT, we systematically measured the T1 and T2 dispersion profiles of rotationally immobilized protein gels (bovine serum albumin), ex vivo pig brains, and ex vivo rat brains with induced stroke. Comparing the ULF results with T1rho dispersion obtained at 3 T and 7 T, we find that the degree of protein immobilization determines the frequency-dependence of both T1 and T1rho. Furthermore, T1rho and ULF T1 show similar results for stroke, suggesting that ULF MRI may be used to image traumatic brain injury with negligible SAR. This research was supported by the Henry H. Wheeler, Jr. Brain Imaging Center and the Donaldson Trust.

  7. Comparative study on functionalized SBA-15 and SBA-16 nanostructured materials used for immobilization of D-amino acid oxidase

    NASA Astrophysics Data System (ADS)

    Hy, Le Gia; Phuong, Dang Tuyet; Yen, Hoang; Hoan, Nguyen Thi Vuong; Linh, Bui Thi Hai; Thang, Hoang vinh; Hoa, Tran Thi Kim; Thang, Dinh Cao; Nguyen, Vu Thi Hanh; Thao, Phan Thi Hong; Giap, Chu Van; Tuan, Vu Anh

    2008-12-01

    SBA-15 and SBA-16 nanostucrured materials were synthesized via hydrothermal treatment and were functionalized with 3-aminopropyltriethoxysilane (APTES), and vinyltriethoxysilane (VTES). The obtained samples were characterized by different techniques such as XRD, BET, IR and TEM. After functionalization, it showed that these nanostrucrured materials were still maintained the hexagonal pore structure of the parent SBA-15 and cubic cage structure of the parent SBA-16. The non-functionalized pure silica SBA-15 and SBA-16 as well as functionalized SBA-15 and SBA-16 materials were used to immobilize DAAO, which is industrially important enzyme for the production of glutaryl 7-amino cephalosporanic acid (GL-7-ACA) from cephalosporin C (CPC). The obtained results revealed that functionalized SBA- 15 and SBA-16 materials exhibited higher enzymatic activity and stability than those of non-functionalized ones. This might be due to the enhancing of surface hydrophobicity upon functionalization. The surface functionalization of the nanostructured silicas with organic groups can enhance the interaction between enzyme and the supports and consequently increasing the operational stability of the immobilized enzyme. The loading of enzyme on SBA-15 materials was higher than that on SBA-16 samples (both functionalized and non-functionalized types). This might be explained by the difference in pore size and type (cylindrical for SBA-15 and bottle-neck for SBA-16) as well as structure shape (hexagonal for SBA-15 and cubic cage for SBA-16) of both mesoporous materials. Additionally, nature of functionalized groups significantly affected the enzymatic activity. Effects on surface binding force, nature of functional groups, pore size of supports were investigated and discussed.

  8. Biotechnological production of vanillin using immobilized enzymes.

    PubMed

    Furuya, Toshiki; Kuroiwa, Mari; Kino, Kuniki

    2017-02-10

    Vanillin is an important and popular plant flavor, but the amount of this compound available from plant sources is very limited. Biotechnological methods have high potential for vanillin production as an alternative to extraction from plant sources. Here, we report a new approach using immobilized enzymes for the production of vanillin. The recently discovered oxygenase Cso2 has coenzyme-independent catalytic activity for the conversion of isoeugenol and 4-vinylguaiacol to vanillin. Immobilization of Cso2 on Sepabeads EC-EA anion-exchange carrier conferred enhanced operational stability enabling repetitive use. This immobilized Cso2 catalyst allowed 6.8mg yield of vanillin from isoeugenol through ten reaction cycles at a 1mL scale. The coenzyme-independent decarboxylase Fdc, which has catalytic activity for the conversion of ferulic acid to 4-vinylguaiacol, was also immobilized on Sepabeads EC-EA. We demonstrated that the immobilized Fdc and Cso2 enabled the cascade synthesis of vanillin from ferulic acid via 4-vinylguaiacol with repetitive use of the catalysts. This study is the first example of biotechnological production of vanillin using immobilized enzymes, a process that provides new possibilities for vanillin production.

  9. An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

    PubMed Central

    Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

    2015-01-01

    The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

  10. [Effect of eleutherococcus on hemostasis in immobilized rats].

    PubMed

    Shakhmatov, I I; Bondarchuk, Iu A; Vdovin, V M; Alekseeva, O V; Kiselev, V I

    2007-01-01

    The influence of a chronic (30 days) administration of an eleutherococcus extract on the haemostatic system state was studied in immobilized rats. A 3-h immobilization of untreated animals is accompanied by hypercoagulation and thrombinemia signs on the background of downregulation of the anticoagulant and fibrinolytic activity, which leads to a risk of thrombosis. Preliminary 30-day course of eleutherococcus uptake prevents the immobilization-induced thrombosis in rats.

  11. Influence of zeolite PZC and pH on the immobilization of cytochrome c: a preliminary study regarding the preparation of new biomaterials.

    PubMed

    Tavolaro, Palmira; Tavolaro, Adalgisa; Martino, Guglielmo

    2009-04-01

    The adsorption of cytochrome c on to zeolite crystals and membranes with different chemical composition and structure was studied. The structure and texture of zeolite materials were identified by X-ray diffraction (XRD) and scanning electron microscopy (FESEM), while the variation of protein conformation was studied by Fourier transform infrared attenuated total reflectance (FTIR-ATR) analysis. In order to separate the influence of zeolite structures from the effect of composite membranes, a through analysis of the cytochrome c adsorption was performed on different crystals by varying several experimental parameters such as: pH value, protein amount, zeolite structures and chemical compositions. It is shown that the electrostatic type of interaction seems to be of the utmost importance to govern the immobilization, while the zeolite Brönsted acidity of the support is the subordinate parameter which differentiates the adsorption performances of different zeolite structures (that distinct for chemical composition of the framework).

  12. Biosensor studies of collagen and laminin binding with immobilized Escherichia coli O157:H7 and inhibition with naturally occurring food additives

    NASA Astrophysics Data System (ADS)

    Medina, Marjorie B.

    1999-01-01

    Escherichia coli O157:H7 outbreaks were mostly due to consumption of undercooked contaminated beef which resulted in severe illness and several fatalities. Recalls of contaminated meat are costly for the meat industry. Our research attempts to understand the mechanisms of bacterial adhesion on animal carcass in order to eliminate or reduce pathogens in foods. We have reported the interactions of immobilized E. coli O157:H7 cells with extracellular matrix (ECM) components using a surface plasmon resonance biosensor (BIAcore). These studies showed that immobilized bacterial cells allowed the study of real-time binding interactions of bacterial surface with the ECM compounds, collagen I, laminin and fibronectin. Collagen I and laminin bound to the E. coli sensor surface with dissociation and association rates ranging from 106 to 109. Binding of collagen I and laminin mixture resulted in synergistic binding signals. An inhibition model was derived using collagen-laminin as the ligand which binds with E. coli sensor. A select group of naturally occurring food additives was evaluated by determining their effectivity in inhibiting the collagen-laminin binding to the bacterial sensor. Bound collagen-laminin was detached from the E. coli sensor surface with the aid of an organic acid. The biosensor results were verified with cell aggregation assays which were observed with optical and electron microscopes. These biosensor studies provided understanding of bacterial adhesion to connective tissue macromolecules. It also provided a model system for the rapid assessment of potential inhibitors that can be used in carcass treatment to inhibit or reduce bacterial contamination.

  13. C-Terminal-oriented Immobilization of Enzymes Using Sortase A-mediated Technique.

    PubMed

    Hata, Yuto; Matsumoto, Takuya; Tanaka, Tsutomu; Kondo, Akihiko

    2015-10-01

    In the present study, sortase A-mediated immobilization of enzymes was used for the preparation of immobilized enzymes. Thermobifida fusca YX β-glucosidase (BGL) or Streptococcus bovis 148 α-amylase (AmyA) were produced with C-terminal sortase A recognition sequences. The resulting fusion proteins were successfully immobilized on nanoparticle surfaces using sortase A. Some properties (activity, stability, and reusability) of the immobilized fusion proteins were evaluated. Both immobilized BGL and immobilized AmyA prepared by the sortase A-mediated technique retained their catalytic activity, exhibiting activities 3.0- or 1.5-fold (respectively) of those seen with the same enzymes immobilized by chemical crosslinking. Immobilized enzymes prepared by the sortase A-mediated technique did not undergo dramatic changes in stability compared with the respective free enzymes. Thus, the sortase A-mediated technique provides a promising method for immobilization of active, stable enzymes.

  14. Immobilizing Yarrowia lipolytica Lipase Lip2 via Improvement of Microspheres by Gelatin Modification.

    PubMed

    Xie, Rong; Cui, Caixia; Chen, Biqiang; Tan, Tianwei

    2015-10-01

    The purpose of this study was to investigate the feasibility of immobilizing Yarrowia lipolytica lipase lip2 on epoxy microspheres with or without gelatin modifications. The activity of lipase immobilized on gelatin-modified supports was twofold higher than those immobilized on native supports. There was no significant difference in the Michaelis-Menten constant (K M ) between the two immobilized lipases. However, lipase immobilized on gelatin modified supports showed an approximately fourfold higher V max than lipase immobilized on native supports. Lipase immobilization on the gelatin-modified support exhibited a significantly improved operational stability in an esterification system. After it was reused for a total of 35 batches, the ester conversion of lipase immobilized on gelatin-modified and native microspheres was 83 and 60 %, respectively. Furthermore, the immobilized lipase could be stored at 4 °C for 12 months without any loss of activity.

  15. Bacillus thuringiensis HCB6 Amylase Immobilization by Chitosan Beads

    NASA Astrophysics Data System (ADS)

    Zusfahair; Ningsih, D. R.; Kartika, D.; Fatoni, A.; Zuliana, A. L.

    2017-02-01

    The purpose of this study was to optimize the amylase immobilization using a chitosan bead and to characterize immobilized amylase of Bacillus thuringiensis Bacteria HCB6. This study was started of amylase production, continued by immobilization optimization including ratio of chitosan:enzymes, enzyme-matrix contact time, substrate concentration, pH effect, incubation temperature effect, reaction time, and stability of immobilized enzyme. Amylase activity assay was dinitro salicylic (DNS) method. The results showed the optimum chitosan:enzyme ratio was 2.5: 1 (v/v), immobilization contact time of 18 hours and immobilization efficiency of 87.93%. Furthermore, immobilized amylase of B. thuringiensis HCB6 showed optimum substrate concentration of 1.5%, optimum pH of 6, optimum incubation temperature of 37 ° C, and the reaction time of 30 minutes. The Michaelis-Menten constant KM value for free and immobilized amylase were 5.30% and 1.33% respectively. Immobilized amylase can be used up to five times with the remaining activity of 43.3%.

  16. [Transformation of icariin by immobilized β-glucosidase and snailase].

    PubMed

    Peng, Jing; Ma, Yi-hua; Chen, Yan; Liu, Cong-Yan; Gao, Xia; Zhou, Jing

    2015-12-01

    This study was performed to prepare immobilized β-glucosidase and snailase, then optimize and compare the process conditions for conversion of icariin. Immobilized β-glucosidase and snailase were prepared using crosslink-embedding method. The best conditions of the preparation process were optimized by single factor analysis and the properties of immobilized β-glucosidase and snailase were investigated. The reaction conditions including temperature, pH, substrate ratio, substrate concentration, reaction time and reusing times of the conversion of icariin using immobilized β-glucosidase or snailase were optimized. Immobilized β-glucosidase and snailase exhibited better heat stabilities and could remain about 60% activity after storage at 4 degrees C for 4 weeks. The optimized conditions for the conversion of icariin were as follows, the temperature of 50 degrees C, pH of 5.0, enzyme and substrate ratio of 1 : 1, substrate concentration of 0.1 mg x mL(-1), reaction time of 6 h for β-glucosidase and 2 h for snailase, respectively. In 5 experiments, the average conversion ratio of immobilized β-glucosidase and snailase was 70.76% and 74.97%. The results suggest an effect of promoted stabilities, prolonged lifetimes in both β-glucosidase and snailase after immobilization. The immobilized β-glucosidase and snailase exhibited a higher conversion rate and reusability compared to the free β-glucosidase and snailase. Moreover, the conversion rate of immobilized snailase was higher than that of immobilized β-glucosidase. The process of icariin conversion using immobilized β-glucosidase and snailase was moderate and feasible, which suggests that immobilized enzymes may hold a promise for industrial usage.

  17. Industrial use of immobilized enzymes.

    PubMed

    DiCosimo, Robert; McAuliffe, Joseph; Poulose, Ayrookaran J; Bohlmann, Gregory

    2013-08-07

    Although many methods for enzyme immobilization have been described in patents and publications, relatively few processes employing immobilized enzymes have been successfully commercialized. The cost of most industrial enzymes is often only a minor component in overall process economics, and in these instances, the additional costs associated with enzyme immobilization are often not justified. More commonly the benefit realized from enzyme immobilization relates to the process advantages that an immobilized catalyst offers, for example, enabling continuous production, improved stability and the absence of the biocatalyst in the product stream. The development and attributes of several established and emerging industrial applications for immobilized enzymes, including high-fructose corn syrup production, pectin hydrolysis, debittering of fruit juices, interesterification of food fats and oils, biodiesel production, and carbon dioxide capture are reviewed herein, highlighting factors that define the advantages of enzyme immobilization.

  18. Determination of conformation and orientation of immobilized peptides and proteins at buried interfaces

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Ulrich, Nathan W.; Mello, Charlene M.; Chen, Zhan

    2015-01-01

    Surface immobilized peptides/proteins have important applications such as antimicrobial coating and biosensing. We report a study of such peptides/proteins using sum frequency generation vibrational spectroscopy and ATR-FTIR. Immobilization on surfaces via physical adsorption and chemical coupling revealed that structures of chemically immobilized peptides are determined by immobilization sites, chemical environments, and substrate surfaces. In addition, controlling enzyme orientation by engineering the surface immobilization site demonstrated that structures can be well-correlated to measured chemical activity. This research facilitates the development of immobilized peptides/proteins with improved activities by optimizing their surface orientation and structure.

  19. Enzymes immobilized in mesoporous silica: a physical-chemical perspective.

    PubMed

    Carlsson, Nils; Gustafsson, Hanna; Thörn, Christian; Olsson, Lisbeth; Holmberg, Krister; Åkerman, Björn

    2014-03-01

    Mesoporous materials as support for immobilized enzymes have been explored extensively during the last two decades, primarily not only for biocatalysis applications, but also for biosensing, biofuels and enzyme-controlled drug delivery. The activity of the immobilized enzymes inside the pores is often different compared to that of the free enzymes, and an important challenge is to understand how the immobilization affects the enzymes in order to design immobilization conditions that lead to optimal enzyme activity. This review summarizes methods that can be used to understand how material properties can be linked to changes in enzyme activity. Real-time monitoring of the immobilization process and techniques that demonstrate that the enzymes are located inside the pores is discussed by contrasting them to the common practice of indirectly measuring the depletion of the protein concentration or enzyme activity in the surrounding bulk phase. We propose that pore filling (pore volume fraction occupied by proteins) is the best standard for comparing the amount of immobilized enzymes at the molecular level, and present equations to calculate pore filling from the more commonly reported immobilized mass. Methods to detect changes in enzyme structure upon immobilization and to study the microenvironment inside the pores are discussed in detail. Combining the knowledge generated from these methodologies should aid in rationally designing biocatalyst based on enzymes immobilized in mesoporous materials.

  20. Study on stability mechanism of immobilized pH gradient in isoelectric focusing via the Svensson-Tiselius differential equation and moving reaction boundary.

    PubMed

    Guo, Chen-Gang; Li, Si; Wang, Hou-Yu; Zhang, Dong; Li, Guo-Qing; Zhang, Jie; Fan, Liu-Yin; Cao, Cheng-Xi

    2013-07-15

    An immobilized pH gradient (IPG) has strong power against instability (e.g., drifting and plateau) existing in classic isoelectric focusing (IEF). However, the relevant mechanism against the instability of pH gradient is still unclear. In this work, the theories of diffusional current and water products in IEF were developed based on the Svensson-Tiselius's differential equation and concept of moving reaction boundary (MRB). Two novel methods of pH gradient mobilization in IPG-IEF and non-IPG-IEF (opposite to IPG-IEF) were developed to unveil stability mechanism of IPG-IEF. The theoretical and experimental results indicated that (i) the drifting of pH gradient in non-IPG-IEF could be effectively controlled by IPG technique due to the existence of equal-fluxes of hydroxyl and hydrogen ions in the IPG-IEF system, (ii) there existed high diffusional current in non-IPG-IEF because of the existence of free carrier ampholyte (CA), but weak current in the IPG-IEF due to the immobilization of CA species in gel matrix, and (iii) the high diffusional current resulted in a great amount of water formation in neutral zone of pH gradient that led to distinct plateau in non-IPG-IEF, conversely the weak diffusional current caused little of water formation and weak plateau of pH gradient in IPG-IEF. These studies have considerable significance to the understanding of mechanism and development of protein IEF separation technique.

  1. Excess Weapons Plutonium Immobilization in Russia

    SciTech Connect

    Jardine, L.; Borisov, G.B.

    2000-04-15

    The joint goal of the Russian work is to establish a full-scale plutonium immobilization facility at a Russian industrial site by 2005. To achieve this requires that the necessary engineering and technical basis be developed in these Russian projects and the needed Russian approvals be obtained to conduct industrial-scale immobilization of plutonium-containing materials at a Russian industrial site by the 2005 date. This meeting and future work will provide the basis for joint decisions. Supporting R&D projects are being carried out at Russian Institutes that directly support the technical needs of Russian industrial sites to immobilize plutonium-containing materials. Special R&D on plutonium materials is also being carried out to support excess weapons disposition in Russia and the US, including nonproliferation studies of plutonium recovery from immobilization forms and accelerated radiation damage studies of the US-specified plutonium ceramic for immobilizing plutonium. This intriguing and extraordinary cooperation on certain aspects of the weapons plutonium problem is now progressing well and much work with plutonium has been completed in the past two years. Because much excellent and unique scientific and engineering technical work has now been completed in Russia in many aspects of plutonium immobilization, this meeting in St. Petersburg was both timely and necessary to summarize, review, and discuss these efforts among those who performed the actual work. The results of this meeting will help the US and Russia jointly define the future direction of the Russian plutonium immobilization program, and make it an even stronger and more integrated Russian program. The two objectives for the meeting were to: (1) Bring together the Russian organizations, experts, and managers performing the work into one place for four days to review and discuss their work with each other; and (2) Publish a meeting summary and a proceedings to compile reports of all the excellent

  2. Evaluation of two-dimensional bolus effect of immobilization/support devices on skin doses: A radiochromic EBT film dosimetry study in phantom

    SciTech Connect

    Chiu-Tsao, Sou-Tung; Chan, Maria F.

    2010-07-15

    Purpose: In this study, the authors have quantified the two-dimensional (2D) perspective of skin dose increase using EBT film dosimetry in phantom in the presence of patient immobilization devices during conventional and IMRT treatments. Methods: For 6 MV conventional photon field, the authors evaluated and quantified the 2D bolus effect on skin doses for six different common patient immobilization/support devices, including carbon fiber grid with Mylar sheet, Orfit carbon fiber base plate, balsa wood board, Styrofoam, perforated AquaPlast sheet, and alpha-cradle. For 6 and 15 MV IMRT fields, a stack of two film layers positioned above a solid phantom was exposed at the air interface or in the presence of a patient alpha-cradle. All the films were scanned and the pixel values were converted to doses based on an established calibration curve. The authors determined the 2D skin dose distributions, isodose curves, and cross-sectional profiles at the surface layers with or without the immobilization/support device. The authors also generated and compared the dose area histograms (DAHs) and dose area products from the 2D skin dose distributions. Results: In contrast with 20% relative dose [(RD) dose relative to d{sub max} on central axis] at 0.0153 cm in the film layer for 6 MV 10x10 cm{sup 2} open field, the average RDs at the same depth in the film layer were 71%, 69%, 55%, and 57% for Orfit, balsa wood, Styrofoam, and alpha-cradle, respectively. At the same depth, the RDs were 54% under a strut and 26% between neighboring struts of a carbon fiber grid with Mylar sheet, and between 34% and 56% for stretched perforated AquaPlast sheet. In the presence of the alpha-cradle for the 6 MV (15 MV) IMRT fields, the hot spot doses at the effective measurement depths of 0.0153 and 0.0459 cm were 140% and 150% (83% and 89%), respectively, of the isocenter dose. The enhancement factor was defined as the ratio of a given DAH parameter (minimum dose received in a given area) with

  3. Enzyme Immobilization: An Overview on Methods, Support Material, and Applications of Immobilized Enzymes.

    PubMed

    Sirisha, V L; Jain, Ankita; Jain, Amita

    2016-01-01

    Immobilized enzymes can be used in a wide range of processes. In recent years, a variety of new approaches have emerged for the immobilization of enzymes that have greater efficiency and wider usage. During the course of the last two decades, this area has rapidly expanded into a multidisciplinary field. This current study is a comprehensive review of a variety of literature produced on the different enzymes that have been immobilized on various supporting materials. These immobilized enzymes have a wide range of applications. These include applications in the sugar, fish, and wine industries, where they are used for removing organic compounds from waste water. This study also reviews their use in sophisticated biosensors for metabolite control and in situ measurements of environmental pollutants. Immobilized enzymes also find significant application in drug metabolism, biodiesel and antibiotic production, bioremediation, and the food industry. The widespread usage of immobilized enzymes is largely due to the fact that they are cheaper, environment friendly, and much easier to use when compared to equivalent technologies.

  4. L-DOPA production by immobilized tyrosinase.

    PubMed

    Carvalho, G M; Alves, T L; Freire, D M

    2000-01-01

    The production of L-DOPA using L-tyrosine as substrate, the enzyme tyrosinase (EC 1.14.18.1) as biocatalyst, and L-ascorbate as reducing agent for the o-quinones produced by the enzymatic oxidation of the substrates was studied. Tyrosinase immobilization was investigated on different supports and chemical agents: chitin flakes activated with hexamethylenediamine and glutaraldehyde as crosslinking agent, chitosan gel beads, chitosan gel beads in the presence of glutaraldehyde, chitosan gel beads in the presence of polyvinylpyrrolidone, and chitosan flakes using glutaraldehyde as crosslinking agent. The last support was considered the best using as performance indexes the following set of immobilization parameters: efficiency (90.52%), yield (11.65%), retention (12.87%), and instability factor (0.00). The conditions of immobilization on chitosan flakes were optimized using a two-level full factorial experimental design. The independent variables were enzyme-support contact time (t), glutaraldehyde concentration (G), and the amount of enzyme units initially offered (UC). The response variable was the total units of enzymatic activity shown by the immobilized enzyme (UIMO). The optimal conditions were t = 24 h, G = 2% (v/v), and UC = 163.7 U. Under these conditions the total units of enzymatic activity shown by the immobilized enzyme (UIMO) was 23.3 U and the rate of L-DOPA production rate was 53.97 mg/(L.h).

  5. Immobilized Cell Research

    DTIC Science & Technology

    1990-10-31

    beads, the plasmid is twice as stable as in cells In a process where immobilized cells produce material grown in continuous culture over 200...carrageenan) or chemically cross-linked, or- Penicillium chrysogenum than in washed freely suspended ganic polymer (Ca-alginate, polyacrylamide, and mycelium ...these materials are formed into the freely suspended cells stopped after 6 days. If the beads of several millimeters in diameter by allowing the

  6. Immobilization of peroxidase on SPEU film via radiation grafting

    NASA Astrophysics Data System (ADS)

    Hongfei, Ha; Guanghui, Wang; Jilan, Wu

    The acrylic acid or acrylamide were grafted via radiation onto segmented polyetherurethane (SPEU) film which is a kind of biocompatible material. Then the Horse radish peroxidase was immobilized on the grafted SPEU film through chemical binding. Some quantitative relationships between the percent graft and the activity, amount of immobilized enzyme were given. The properties and application of obtained biomaterial was studied as well.

  7. Isomaltulose production using immobilized cells.

    PubMed

    Chhetham, P S; Garrett, C; Clark, J

    1985-04-01

    Three strains of Erwinia rhapontici especially suitable for use in the form of nongrowing immobilized cells were selected by screening strains of cells for high activity and operational stability in an immobilized form. Immobilization in calcium alginate gel pellets was easily the best method of immobilizing E. rhapontici. Much greater operational stabilities were obtained than when other immobilization methods were used. Conditions of operation which optimize the activity, stability, and yield and the ease of operation of the immobilized cell columns working in a steady state are described. These include the effects of substrate concentration, diffusional restrictions and water activity, the concentration of cells immobilized, and the type of reactor used. Thus, the immobilized cells produce about 1500 times their own weight of isomaltulose during one half-life of use (ca. 1 year). Loss of activity was most closely correlated with the volume of substrate processed and so presumably is due to the presence of low concentrations of a cummulative inhibitor in the substrate. Methods for regenerating the activity of the immobilized cells by the periodic administration of nutrients, of forming isomaltulose by continuously supplying nutrients to growing immobilized cells, and of crystallizing isomaltulose from the column eluate are also described.

  8. Uranium immobilization and nuclear waste

    SciTech Connect

    Duffy, C.J.; Ogard, A.E.

    1982-02-01

    Considerable information useful in nuclear waste storage can be gained by studying the conditions of uranium ore deposit formation. Further information can be gained by comparing the chemistry of uranium to nuclear fission products and other radionuclides of concern to nuclear waste disposal. Redox state appears to be the most important variable in controlling uranium solubility, especially at near neutral pH, which is characteristic of most ground water. This is probably also true of neptunium, plutonium, and technetium. Further, redox conditions that immobilize uranium should immobilize these elements. The mechanisms that have produced uranium ore bodies in the Earth's crust are somewhat less clear. At the temperatures of hydrothermal uranium deposits, equilibrium models are probably adequate, aqueous uranium (VI) being reduced and precipitated by interaction with ferrous-iron-bearing oxides and silicates. In lower temperature roll-type uranium deposits, overall equilibrium may not have been achieved. The involvement of sulfate-reducing bacteria in ore-body formation has been postulated, but is uncertain. Reduced sulfur species do, however, appear to be involved in much of the low temperature uranium precipitation. Assessment of the possibility of uranium transport in natural ground water is complicated because the system is generally not in overall equilibrium. For this reason, Eh measurements are of limited value. If a ground water is to be capable of reducing uranium, it must contain ions capable of reducing uranium both thermodynamically and kinetically. At present, the best candidates are reduced sulfur species.

  9. Effects of immobilization on spermiogenesis

    NASA Technical Reports Server (NTRS)

    Meitner, E. R.

    1980-01-01

    The influence of immobilization stress on spermiogenesis in rats was investigated. After 96 hour immobilization, histological changes began to manifest themselves in the form of practically complete disappearance of cell population of the wall of seminiferous tubule as well as a markedly increased number of cells with pathologic mitoses. Enzymological investigations showed various changes of activity (of acid and alkaline phosphatase and nonspecific esterase) in the 24, 48, and 96 hour immobilization groups.

  10. The biosorption capacity of biochar for 4-bromodiphengl ether: study of its kinetics, mechanism, and use as a carrier for immobilized bacteria.

    PubMed

    Du, Jingting; Sun, Pengfei; Feng, Zhuo; Zhang, Xin; Zhao, Yuhua

    2016-02-01

    Polybrominated diphenyl ethers (PBDEs) are known as ubiquitous pollutants in ecological systems and thus pose a great threat to the health of humans and other organisms due to their bioamplification and bioaccumulation along the food chain. The present study was designed to investigate the biosorption capacity of biochar for the removal of 4-monobromodiphengl ether and its synergistic effect when used as a carrier to immobilize the 4-monobromodiphengl ether-degrading strain Sphingomonas sp. DZ3. The raw biochar material was prepared by pyrolyzing maize straw at 350 °C under oxygen-limited conditions. The maximum biosorption capacity of biochar for 4-bromodiphengl ether was determined to be 50.23 mg/L under an initial concentration of 800 mg/L at pH 7.0 and 40 °C. The data obtained from the biosorption studies were fitted successfully with the pseudo-first-order kinetic and Freundlich isotherm models. The Weber-Morris model analysis indicated that intraparticle diffusion was the limiting step in the biosorption of 4-bromodiphengl ether onto the biosorbent. The values of thermodynamic parameters △G0 were calculated as -24.61 kJ/mol (20 °C), -24.35 kJ/mol (30 °C), and -23.98 kJ/mol (40 °C), △S(0) was -8.45 kJ/mol/K, and △H(0) was 21.36 kJ/mol. The artificial neural network analysis indicated that the initial concentration appeared to be the most influential parameter on the biosorption processes. The removal rate of 4-bromodiphengl ether achieved using the biochar-microorganism system was increased by 63 and 83% compared with the rates obtained with biochar and the strain individually, respectively. The morphology of the biochar and immobilized strain was determined using a scanning electron microscope, and information of the surface functional groups of biochar was obtained through an infrared spectra study.

  11. [Immobilization of penicilin G acylase on polyacrylonitrile fiber].

    PubMed

    Xian, H; Wang, Z

    2001-08-01

    The immobilization of Penicillin G Acylase from Bacillus megaterium by glutaraldehyde crosslinking on the partially acid-hydrolyed polyacrylonitrile fiber was studied. When the amount of--NH2 on fiber were 690 mumol/g and the moisture in the fiber was 64%, and the content of enzyme protein immobilized on fiber was more than 100 mg/g. The activity of 2300 IU/g was obtained with 30% of overall yield and 56% of binding efficiency. The immobilization yield was markedly influenced by ratio of the amount of free enzyme used to the weight of the fiber. The half-life of storage stability of immobilized PGA at room temperature was 130 days. The immobilized PGA kept 80% of the initial activity after 20 cycles of operation in 10% of PGK(W/V) in 0.05 mol/L phosphate buffer, pH 8.0, at 37 degrees C and an enzyme load of 150 IU/g(PGK) and 10 g(PGK) for per cycle of operation. The hydrolysis conversion of PGK in the range of 2.5%-12.5% (W/V) were over 98% for the immobilized PGA. The operation stability of immobilized PGA treated with DTT was better than that of immobilized PGA untreated.

  12. IN SITU LEAD IMMOBILIZATION BY APATITE

    EPA Science Inventory

    Lead contamination is of environmental concern due to its effect on human health. The purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. Hydroxyapatite [Ca10(PO4)6(O...

  13. Use of reversible denaturation for adsorptive immobilization of urease.

    PubMed

    Azari, F; Hosseinkhani, S; Nemat-Gorgani, M

    2001-06-01

    Urease was chosen as a model multimeric protein to investigate the utility of reversible denaturation for immobilization to a hydrophobic support. Of the various procedures investigated, acidic denaturation provided the highest degree of immobilization and enzymatic activity with lowering of Km (apparent). Exposure of hydrophobic clusters in the protein molecule induced by the acidic pH environment was confirmed by fluorescence studies using 8-anilino-1-naphtalene-sulfonate as a hydrophobic-reporter probe. The catalytic potential of the enzyme at low pH values was dramatically improved with significant heat and pH stability enhancement on immobilization. Furthermore, the immobilized preparation was used successfully in continuous catalytic transformations. Based on the results presented in this article and a recent report involving a relatively more simple monomeric protein, it is suggested that reversible denaturation may be of general utility for immobilization of proteins, which are not normally adsorbed on hydrophobic supports.

  14. Metabolic alkalosis during immobilization in monkeys (M. nemestrina)

    NASA Technical Reports Server (NTRS)

    Young, D. R.; Yeh, I.; Swenson, R. S.

    1983-01-01

    The systemic and renal acid-base response of monkeys during ten weeks of immobilization was studied. By three weeks of immobilization, arterial pH and bicarbonate concentrations were elevated (chronic metabolic alkalosis). Net urinary acid excretion increased in immobilized animals. Urinary bicarbonate excretion decreased during the first three weeks of immobilization, and then returned to control levels. Sustained increases in urinary ammonium excretion were seen throughout the time duration of immobilization. Neither potassium depletion nor hypokalemia was observed. Most parameters returned promptly to the normal range during the first week of recovery. Factors tentatively associated with changes in acid-base status of monkeys include contraction of extracellular fluid volume, retention of bicarbonate, increased acid excretion, and possible participation of extrarenal buffers.

  15. Electron tomography of cryo-immobilized plant tissue: a novel approach to studying 3D macromolecular architecture of mature plant cell walls in situ.

    PubMed

    Sarkar, Purbasha; Bosneaga, Elena; Yap, Edgar G; Das, Jyotirmoy; Tsai, Wen-Ting; Cabal, Angelo; Neuhaus, Erica; Maji, Dolonchampa; Kumar, Shailabh; Joo, Michael; Yakovlev, Sergey; Csencsits, Roseann; Yu, Zeyun; Bajaj, Chandrajit; Downing, Kenneth H; Auer, Manfred

    2014-01-01

    Cost-effective production of lignocellulosic biofuel requires efficient breakdown of cell walls present in plant biomass to retrieve the wall polysaccharides for fermentation. In-depth knowledge of plant cell wall composition is therefore essential for improving the fuel production process. The precise spatial three-dimensional (3D) organization of cellulose, hemicellulose, pectin and lignin within plant cell walls remains unclear to date since the microscopy techniques used so far have been limited to two-dimensional, topographic or low-resolution imaging, or required isolation or chemical extraction of the cell walls. In this paper we demonstrate that by cryo-immobilizing fresh tissue, then either cryo-sectioning or freeze-substituting and resin embedding, followed by cryo- or room temperature (RT) electron tomography, respectively, we can visualize previously unseen details of plant cell wall architecture in 3D, at macromolecular resolution (∼ 2 nm), and in near-native state. Qualitative and quantitative analyses showed that wall organization of cryo-immobilized samples were preserved remarkably better than conventionally prepared samples that suffer substantial extraction. Lignin-less primary cell walls were well preserved in both self-pressurized rapidly frozen (SPRF), cryo-sectioned samples as well as high-pressure frozen, freeze-substituted and resin embedded (HPF-FS-resin) samples. Lignin-rich secondary cell walls appeared featureless in HPF-FS-resin sections presumably due to poor stain penetration, but their macromolecular features could be visualized in unprecedented details in our cryo-sections. While cryo-tomography of vitreous tissue sections is currently proving to be instrumental in developing 3D models of lignin-rich secondary cell walls, here we confirm that the technically easier method of RT-tomography of HPF-FS-resin sections could be used immediately for routine study of low-lignin cell walls. As a proof of principle, we characterized the

  16. Electron Tomography of Cryo-Immobilized Plant Tissue: A Novel Approach to Studying 3D Macromolecular Architecture of Mature Plant Cell Walls In Situ

    PubMed Central

    Sarkar, Purbasha; Bosneaga, Elena; Yap, Edgar G.; Das, Jyotirmoy; Tsai, Wen-Ting; Cabal, Angelo; Neuhaus, Erica; Maji, Dolonchampa; Kumar, Shailabh; Joo, Michael; Yakovlev, Sergey; Csencsits, Roseann; Yu, Zeyun; Bajaj, Chandrajit; Downing, Kenneth H.; Auer, Manfred

    2014-01-01

    Cost-effective production of lignocellulosic biofuel requires efficient breakdown of cell walls present in plant biomass to retrieve the wall polysaccharides for fermentation. In-depth knowledge of plant cell wall composition is therefore essential for improving the fuel production process. The precise spatial three-dimensional (3D) organization of cellulose, hemicellulose, pectin and lignin within plant cell walls remains unclear to date since the microscopy techniques used so far have been limited to two-dimensional, topographic or low-resolution imaging, or required isolation or chemical extraction of the cell walls. In this paper we demonstrate that by cryo-immobilizing fresh tissue, then either cryo-sectioning or freeze-substituting and resin embedding, followed by cryo- or room temperature (RT) electron tomography, respectively, we can visualize previously unseen details of plant cell wall architecture in 3D, at macromolecular resolution (∼2 nm), and in near-native state. Qualitative and quantitative analyses showed that wall organization of cryo-immobilized samples were preserved remarkably better than conventionally prepared samples that suffer substantial extraction. Lignin-less primary cell walls were well preserved in both self-pressurized rapidly frozen (SPRF), cryo-sectioned samples as well as high-pressure frozen, freeze-substituted and resin embedded (HPF-FS-resin) samples. Lignin-rich secondary cell walls appeared featureless in HPF-FS-resin sections presumably due to poor stain penetration, but their macromolecular features could be visualized in unprecedented details in our cryo-sections. While cryo-tomography of vitreous tissue sections is currently proving to be instrumental in developing 3D models of lignin-rich secondary cell walls, here we confirm that the technically easier method of RT-tomography of HPF-FS-resin sections could be used immediately for routine study of low-lignin cell walls. As a proof of principle, we characterized the

  17. [Covalent immobilization of glucose oxidase within organic media].

    PubMed

    Zhou, Tao; Zhu, Xiongjun; Su, Jianhua; Yao, Dongsheng; Liu, Daling

    2012-04-01

    Activity losing during the covalent immobilization of enzyme is a serious problem. Here we studied organic phase immobilization by using glucose oxidase (GOD) as a model. After lyophilized at optimum pH, GOD is covalently immobilized onto glutaraldhyde-activated chitosan microsphere carrier under the condition of water, 1, 4-dioxane, ether and ethanol separately. The special activities, enzyme characterization and kinetic parameters are determined. Results show that all of the organic phase immobilized GODs have higher special activities and larger K(cat) than that of aqueous phase. Under the conditions of 0.1% of glutaraldehyde, 1.6% moisture content with 80 mg of GOD added to per gram of carrier, 2.9-fold of the special activity and 3-fold of the effective activity recovery ratio were obtained, and 3-fold of the residue activity was demonstrated after 7 runs when compares 1, 4-dioxane phase immobilized GOD with water phase immobilized one. In addition, kinetic study shows that 1,4-dioxane immobilized GOD (Km(app) = 5.63 mmol/L, V(max) = 1.70 micromol/(min x mg GOD), K(cat) = 0.304 s(-1) was superior to water immobilized GOD (Km(app) = 7.33 mmol/L, V(max) = 1.02 micromol/(min x mg GOD), K(cat) = 0.221 s(-1)). All above indicated GOD immobilized in proper organic media presented a better activity with improved catalytic performance. Organic phase immobilization might be one of the ways to overcome the conformational denature of enzyme protein during covalent modification.

  18. Effect of low molecular weight additives on immobilization strength, activity, and conformation of protein immobilized on PVC and UHMWPE.

    PubMed

    Kondyurin, Alexey; Nosworthy, Neil J; Bilek, Marcela M M

    2011-05-17

    Horseradish peroxidase (HRP) was immobilized onto both plasticized and unplasticized polyvinylchloride (PVC) and ultrahigh molecular weight polyethylene (UHMWPE). Plasma immersion ion implantation (PIII) in a nitrogen plasma with 20 kV bias was used to facilitate covalent immobilization and to improve the wettability of the surfaces. The surfaces and immobilized protein were studied using attenuated total reflection infrared (ATR-IR) spectroscopy and water contact angle measurements. Protein elution on exposure to repeated sodium dodecyl sulfate (SDS) washing was used to assess the strength of HRP immobilization. The presence of low molecular weight components (plasticizer, additives in solvent, unreacted monomers, adsorbed molecules on surface) was found to have a major influence on the strength of immobilization and the conformation of the protein on the samples not exposed to the PIII treatment. A phenomenological model considering interactions between the low molecular weight components, the protein molecule, and the surface is developed to explain these observations.

  19. Immobilization of horseradish peroxidase onto kaolin.

    PubMed

    Šekuljica, Nataša Ž; Prlainović, Nevena Ž; Jovanović, Jelena R; Stefanović, Andrea B; Djokić, Veljko R; Mijin, Dušan Ž; Knežević-Jugović, Zorica D

    2016-03-01

    Kaolin showed as a very perspective carrier for the enzyme immobilization and it was used for the adsorption of horseradish peroxidase (HRP). The effects of the enzyme concentration and pH on the immobilization efficiency were studied in the reaction with pyrogallol and anthraquinone dye C.I. Acid Violet 109 (AV 109). In addition, Fourier transform infrared spectroscopy, scanning electron microscopy and analysis by Brunauer-Emmett-Teller were performed for kaolin, thermally activated kaolin and the immobilized enzyme. It has been shown that 0.1 IU of HRP-kaolin decolorized 87 % of dye solution, under the optimal conditions (pH 5.0, temperature 24 °C, dye concentration 40 mg/L and 0.2 mM of H2O2) within 40 min. The immobilized HRP decolorization follows the Ping Pong Bi-Bi mechanism with dead-end inhibition by the dye. The biocatalyst retained 35 ± 0.9 % of the initial activity after seven cycles of reuse in the decolorization reaction of AV 109 under optimal conditions in a batch reactor. The obtained kinetic parameters and reusability study confirmed improvement in performances of k-HRP compared to free, indicating that k-HRP has a great potential for environmental purposes.

  20. Immobilization of Pb, Cd, and Zn in a contaminated soil using eggshell and banana stem amendments: metal leachability and a sequential extraction study.

    PubMed

    Ashrafi, Mehrnaz; Mohamad, Sharifah; Yusoff, Ismail; Shahul Hamid, Fauziah

    2015-01-01

    Heavy-metal-contaminated soil is one of the major environmental pollution issues all over the world. In this study, two low-cost amendments, inorganic eggshell and organic banana stem, were applied to slightly alkaline soil for the purpose of in situ immobilization of Pb, Cd, and Zn. The artificially metal-contaminated soil was treated with 5% eggshell or 10% banana stem. To simulate the rainfall conditions, a metal leaching experiment for a period of 12 weeks was designed, and the total concentrations of the metals in the leachates were determined every 2 weeks. The results from the metal leaching analysis revealed that eggshell amendment generally reduced the concentrations of Pb, Cd, and Zn in the leachates, whereas banana stem amendment was effective only on the reduction of Cd concentration in the leachates. A sequential extraction analysis was carried out at the end of the experiment to find out the speciation of the heavy metals in the amended soils. Eggshell amendment notably decreased mobility of Pb, Cd, and Zn in the soil by transforming their readily available forms to less accessible fractions. Banana stem amendment also reduced exchangeable form of Cd and increased its residual form in the soil.

  1. Potential immobilized Saccharomyces cerevisiae as heavy metal removal

    NASA Astrophysics Data System (ADS)

    Raffar, Nur Izzati Abdul; Rahman, Nadhratul Nur Ain Abdul; Alrozi, Rasyidah; Senusi, Faraziehan; Chang, Siu Hua

    2015-05-01

    Biosorption of copper ion using treated and untreated immobilized Saccharomyces cerevisiae from aqueous solution was investigate in this study. S.cerevisiae has been choosing as biosorbent due to low cost, easy and continuously available from various industries. In this study, the ability of treated and untreated immobilized S.cerevisiae in removing copper ion influence by the effect of pH solution, and initial concentration of copper ion with contact time. Besides, adsorption isotherm and kinetic model also studied. The result indicated that the copper ion uptake on treated and untreated immobilized S.cerevisiae was increased with increasing of contact time and initial concentration of copper ion. The optimum pH for copper ion uptake on untreated and treated immobilized S.cerevisiae at 4 and 6. From the data obtained of copper ion uptake, the adsorption isotherm was fitted well by Freundlich model for treated immobilized S.cerevisiae and Langmuir model for untreated immobilized S.cerevisiae according to high correlation coefficient. Meanwhile, the pseudo second order was described as suitable model present according to high correlation coefficient. Since the application of biosorption process has been received more attention from numerous researchers as a potential process to be applied in the industry, future study will be conducted to investigate the potential of immobilized S.cerevisiae in continuous process.

  2. Two-dimensional (2D) infrared correlation study of the structural characterization of a surface immobilized polypeptide film stimulated by pH

    NASA Astrophysics Data System (ADS)

    Chae, Boknam; Son, Seok Ho; Kwak, Young Jun; Jung, Young Mee; Lee, Seung Woo

    2016-11-01

    The pH-induced structural changes to surface immobilized poly (L-glutamic acid) (PLGA) films were examined by Fourier transform infrared (FTIR) spectroscopy and two-dimensional (2D) correlation analysis. Significant spectral changes were observed in the FTIR spectra of the surface immobilized PLGA film between pH 6 and 7. The 2D correlation spectra constructed from the pH-dependent FTIR spectra of the surface immobilized PLGA films revealed the spectral changes induced by the alternations of the protonation state of the carboxylic acid group in the PLGA side chain. When the pH was increased from 6 to 8, weak spectral changes in the secondary structure of the PLGA main chain were induced by deprotonation of the carboxylic acid side group.

  3. Status of immobilization of excess weapons plutonium in Russia

    SciTech Connect

    Borisov, G B; Jardine, L; Mansourov, O A

    1999-02-03

    In this paper, we examine the logic and framework for the development of a capability to immobilize excess Russian weapons plutonium by the year 2004. The initial activities underway in Russia, summarized here, include engineering feasibility studies of the immobilization of plutonium-containing materials at the Krasnoyarsk and Mayak industrial sites. In addition, research and development (R&D) studies are underway at Russian institutes to develop glass and ceramic forms suitable for the immobilization of plutonium-containing materials, residues, and wastes and for their geologic disposal.

  4. Immobilization of amyloglucosidase onto macroporous cryogels for continuous glucose production from starch.

    PubMed

    Uygun, Murat; Akduman, Begüm; Ergönül, Bülent; Aktaş Uygun, Deniz; Akgöl, Sinan; Denizli, Adil

    2015-01-01

    Poly(methyl methacrylate-glycidyl methacrylate) [Poly(MMA-GMA)] cryogels were synthesized using monomers of methylmethacrylic acid and epoxy group bearing GMA via radical cryopolymerization technique. Synthesized cryogels were used for the immobilization of amyloglucosidase to the cryogel surface using epoxy chemistry. Characterizations of the free and immobilized amyloglucosidase were carried out by comparing the optimum and kinetic parameters of enzymes. For this, pH and temperature profiles of free and immobilized preparation were studied and, it was found that, optimum pH of enzyme was not change upon immobilization (pH 5.0), while optimum temperature of the enzyme shifted 10 °C to warmer region after immobilization (optimum temperatures for free and immobilized enzyme were 55 and 65 °C, respectively). Kinetic parameters of free and immobilized enzyme were also investigated and Km values of free and immobilized amyloglucosidase were found to be 2.743 and 0.865 mg/mL, respectively. Vmax of immobilized amyloglucosidase was found to be (0.496 µmol/min) about four times less than that of free enzyme (2.020 µmol/min). Storage and operational stabilities of immobilized amyloglucosidase were also studied and it was showed that immobilized preparation had much more stability than free preparation. In the present work, amyloglucosidase immobilized poly(MMA-GMA) cryogels were used for continuous glucose syrup production from starch for the first time. Efficiency of immobilized enzyme was investigated and released amount of glucose was found to be 2.54 mg/mL at the end of the 5 min of hydrolysis. The results indicate that the epoxy functionalized cryogels offer a good alternative for amyloglucosidase immobilization applications with increased operational and thermal stability, and reusability. Also, these cryogels can be used for immobilization of other industrially valuable enzymes beyond amyloglucosidase.

  5. Influence of ROM Exercise on the Joint Components during Immobilization.

    PubMed

    Matsuzaki, Taro; Yoshida, Shinya; Kojima, Satoshi; Watanabe, Masanori; Hoso, Masahiro

    2013-12-01

    [Purpose] The aim of this study was to clarify the effects of the ROM exercise on joint components according to histopathological analysis. [Subjects and Methods] In total, twenty-six 9-week-old adult male Wistar rats were used in this study. The rats were randomly divided into three groups, the immobilization group (n=10), exercise group (n=10), and control group (n=6). The immobilization group and exercise group were anaesthetized and operated on under sterile conditions. The right knee joints in the immobilization group and exercise group were immobilized with external fixation at 120 degrees of flexion. Range of motion exercise was started from the day after immobilization. ROM exercise was performed in the exercise group once a day for 3 minutes, 6 days a week, for 2 weeks. [Result] The joint capsule in the immobilization group and exercise group showed narrowing of the collagen bundles in interstitial spaces but was less dense in the control group. In the immobilized group, a hyperplastic reaction was associated with infiltration into the articular cavity and adhesion to the surface of the articular cartilage. Conversely, in the exercise group, hyperplasia of tissue was localized to the synovial membrane. [Conclusion] This finding may suggest that ROM exercise induces some changes within the joint components and tissue metabolism.

  6. Advances in ethanol production using immobilized cell systems

    SciTech Connect

    Margaritis, A.; Merchant, F.J.A.

    1984-01-01

    The application of immobilized cell systems for the production of ethanol has resulted in substantial improvements in the efficiency of the process when compared to the traditional free cell system. In this review, the various methods of cell immobilization employed in ethanol production systems have been described in detail. Their salient features, performance characteristics, advantages and limitations have been critically assessed. More recently, these immobilized cell systems have also been employed for the production of ethanol from non-conventional feedstocks such as Jerusalem artichoke extracts, cheese whey, cellulose, cellobiose and xylose. Ethanol production by immobilized yeast and bacterial cells has been attempted in various bioreactor types. Although most of these studies have been carried out using laboratory scale prototype bioreactors, it appears that only fluidized bed, horizontally packed bed bioreactors and tower fermenters may find application on scale-up. Several studies have indicated that upon immobilization, yeast cells performing ethanol fermentation exhibit more favourable physiological and metabolic properties. This, in addition to substantial improvements in ethanol productivities by immobilized cell systems, is indicative of the fact that future developments in the production of ethanol and alcoholic beverages will be directed towards the use of immobilized cell systems. 291 references.

  7. Covalent immobilization of invertase on PAMAM-dendrimer modified superparamagnetic iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Uzun, K.; Çevik, E.; Şenel, M.; Sözeri, H.; Baykal, A.; Abasıyanık, M. F.; Toprak, M. S.

    2010-10-01

    In this study, polyamidoamine (PAMAM) dendrimer was synthesized on the surface of superparamagnetite nanoparticles to enhance invertase immobilization. The amount of immobilized enzyme on the surface-hyperbranched magnetite nanoparticle was up to 2.5 times (i.e., 250%) as much as that of magnetite nanoparticle modified with only amino silane. Maximum reaction rate ( V max) and Michaelis-Menten constant ( K m) were determined for the free and immobilized enzymes. Various characteristics of immobilized invertase such as; the temperature activity, thermal stability, operational stability, and storage stability were evaluated and results revealed that stability of the enzyme is improved upon immobilization.

  8. Immobilized soybean hull peroxidase for the oxidation of phenolic compounds in coffee processing wastewater.

    PubMed

    Chagas, Pricila Maria Batista; Torres, Juliana Arriel; Silva, Maria Cristina; Corrêa, Angelita Duarte

    2015-11-01

    Chitosan beads were prepared, using glutaraldehyde as a crosslinking agent for the immobilization of soybean hull peroxidase (SBP). The activity of free and immobilized SBP was studied. The optimum pH was 6.0 for both the free and immobilized enzyme; however, enzyme activity became more dependent on the temperature after immobilization. This study evaluated the potential use of immobilized and free enzyme in the oxidation of caffeic acid, of synthetic phenolic solution (SPS) and of total phenolic compounds in coffee processing wastewater (CPW). Some factors, such as reaction time, amount of H2O2 and caffeic acid were evaluated, in order to determine the optimum conditions for enzyme performance. Both enzymes showed a potential in the removal of caffeic acid, SPS and CPW, and immobilized SBP had the highest oxidation performance. The immobilized enzyme showed a potential of 50% in the oxidation of caffeic acid after 4 consecutive cycles.

  9. Uranium Immobilization in Wetland Soils

    NASA Astrophysics Data System (ADS)

    Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

    2014-05-01

    In wetlands, which are a major feature at the groundwater-surface water interface, plants deliver oxygen to the subsurface to keep root tissue aerobic. Some of this oxygen leaches into the rhizosphere where it will oxidize iron that typically precipitates on or near roots. Furthermore, plans provide carbon via root exudates and turnover, which in the presence of the iron oxides drives the activity of heterotrophic iron reducers in wetland soils. Oxidized iron is an important electron acceptor for many microbially-driven transformations, which can affect the fate and transport of several pollutants. It has been shown that heterotrophic iron reducing organisms, such as Geobacter sp., can reduce water soluble U(VI) to insoluble U(IV). The goal of this study was to determine if and how iron cycling in the wetland rhizosphere affects uranium dynamics. For this purpose, we operated a series of small-scale wetland mesocosms in a greenhouse to simulate the discharge of uranium-contaminated groundwater to surface waters. The mesocosms were operated with two different Fe(II) loading rates, two plant types, and unplanted controls. The mesocosms contained zones of root exclusion to differentiate between the direct presence and absence of roots in the planted mesocosms. The mesocosms were operated for several month to get fully established, after which a U(VI) solution was fed for 80 days. The mesocosms were then sacrificed and analyzed for solid-associated chemical species, microbiological characterization, micro-X-ray florescence (µ-XRF) mapping of Fe and U on the root surface, and U speciation via X-ray Absorption Near Edge Structure (XANES). Results showed that bacterial numbers including Geobacter sp., Fe(III), as well as total uranium, were highest on roots, followed by sediments near roots, and lowest in zones without much root influence. Results from the µ-XRF mapping on root surfaces indicated a strong spatial correlation between Fe and U. This correlation was

  10. Development and Validation of a Small Animal Immobilizer and Positioning System for the Study of Delivery of Intracranial and Extracranial Radiotherapy Using the Gamma Knife System.

    PubMed

    Awan, Musaddiq J; Dorth, Jennifer; Mani, Arvind; Kim, Haksoo; Zheng, Yiran; Mislmani, Mazen; Welford, Scott; Yuan, Jiankui; Wessels, Barry W; Lo, Simon S; Letterio, John; Machtay, Mitchell; Sloan, Andrew; Sohn, Jason W

    2017-04-01

    The purpose of this research is to establish a process of irradiating mice using the Gamma Knife as a versatile system for small animal irradiation and to validate accurate intracranial and extracranial dose delivery using this system. A stereotactic immobilization device was developed for small animals for the Gamma Knife head frame allowing for isocentric dose delivery. Intercranial positional reproducibility of a reference point from a primary reference animal was verified on an additional mouse. Extracranial positional reproducibility of the mouse aorta was verified using 3 mice. Accurate dose delivery was validated using film and thermoluminescent dosimeter measurements with a solid water phantom. Gamma Knife plans were developed to irradiate intracranial and extracranial targets. Mice were irradiated validating successful targeted radiation dose delivery. Intramouse positional variability of the right mandible reference point across 10 micro-computed tomography scans was 0.65 ± 0.48 mm. Intermouse positional reproducibility across 2 mice at the same reference point was 0.76 ± 0.46 mm. The accuracy of dose delivery was 0.67 ± 0.29 mm and 1.01 ± 0.43 mm in the coronal and sagittal planes, respectively. The planned dose delivered to a mouse phantom was 2 Gy at the 50% isodose with a measured thermoluminescent dosimeter dose of 2.9 ± 0.3 Gy. The phosphorylated form of member X of histone family H2A (γH2AX) staining of irradiated mouse brain and mouse aorta demonstrated adjacent tissue sparing. In conclusion, our system for preclinical studies of small animal irradiation using the Gamma Knife is able to accurately deliver intracranial and extracranial targeted focal radiation allowing for preclinical experiments studying focal radiation.

  11. Student Collaboration in a Series of Integrated Experiments to Study Enzyme Reactor Modeling with Immobilized Cell-Based Invertase

    ERIC Educational Resources Information Center

    Taipa, M. A^ngela; Azevedo, Ana M.; Grilo, Anto´nio L.; Couto, Pedro T.; Ferreira, Filipe A. G.; Fortuna, Ana R. M.; Pinto, Ine^s F.; Santos, Rafael M.; Santos, Susana B.

    2015-01-01

    An integrative laboratory study addressing fundamentals of enzyme catalysis and their application to reactors operation and modeling is presented. Invertase, a ß-fructofuranosidase that catalyses the hydrolysis of sucrose, is used as the model enzyme at optimal conditions (pH 4.5 and 45 °C). The experimental work involves 3 h of laboratory time…

  12. Weldon Spring, Missouri, Raffinate Pits 1, 2, 3, and 4: Preliminary grout development screening studies for in situ waste immobilization

    SciTech Connect

    McDaniel, E.W.; Gilliam, T.M.; Dole, L.R.; West, G.A.

    1987-04-01

    Results of Oak Ridge National Laboratory's initial support program to develop a preliminary grout formula to solidify in situ the Weldon Spring waste are presented. The screening study developed preliminary formulas based on a simulated composite waste and then tested the formulas on actual waste samples. Future data needs are also discussed. 1 ref., 6 figs., 9 tabs.

  13. Waste immobilization process development at the Savannah River Plant

    SciTech Connect

    Charlesworth, D L

    1986-01-01

    Processes to immobilize various wasteforms, including waste salt solution, transuranic waste, and low-level incinerator ash, are being developed. Wasteform characteristics, process and equipment details, and results from field/pilot tests and mathematical modeling studies are discussed.

  14. Application of immobilized cells to the treatment of cyanide wastewater.

    PubMed

    Chen, C Y; Kao, C M; Chen, S C; Chien, H Y; Lin, C E

    2007-01-01

    Cyanide is highly toxic to living organisms, particularly in inactivating the respiration system by tightly binding to terminal oxidase. To protect the environment and water bodies, wastewater containing cyanide must be treated before discharging into the environment. Biological treatment is a cost-effective and environmentally acceptable method for cyanide removal compared with the other techniques currently in use. Klebsiella oxytoca (K. oxytoca), isolated from cyanide-containing industrial wastewater, has been shown to be able to biodegrade cyanide to non-toxic end products. The technology of immobilized cells can be applied in biological treatment to enhance the efficiency and effectiveness of biodegradation. In this study, potassium cyanide (KCN) was used as the target compound and both alginate (AL) and cellulose triacetate (CTA) techniques were applied for the preparation of immobilized cells. Results from this study show that KCN can be utilized as the sole nitrogen source by K. oxytoca. The free suspension systems reveal that the cell viability was highly affected by initial KCN concentration, pH, and temperature. Results show that immobilized cell systems could tolerate a higher level of KCN concentration and wider ranges of pH and temperature, especially in the system with CTA gel beads. Results show that a longer incubation period was required for KCN degradation using immobilized cells compared to the free suspended systems. This might be due to internal mass transfer limitations. Results also indicate that immobilized systems can support a higher biomass concentration. Complete KCN degradation was observed after the operation of four consecutive degradation experiments with the same batch of immobilized cells. This suggests that the activity of the immobilized cells can be maintained and KCN can be used as the nitrogen source throughout KCN degradation experiments. Results reveal that the application of immobilized cells of K. oxytoca is advantageous

  15. Acetylcholinesterase immobilized onto PEI-coated silica nanoparticles.

    PubMed

    Tumturk, Hayrettin; Yüksekdag, Hazer

    2016-01-01

    Polyethyleneimine (PEI) coated-silica nanoparticles were prepared by the Stöber method. The formation and the structure of the nanoparticles were characterized by ATR-FT-IR spectroscopy and transmission electron microscopy (TEM). TEM images of the silica and PEI-coated nanoparticles revealed that they were well dispersed and that there was no agglomeration. The acetylcholineesterase enzyme was immobilized onto these nanoparticles. The effects of pH and temperature on the storage stability of the free and immobilized enzyme were investigated. The optimum pHs for free and immobilized enzymes were determined as 7.0 and 8.0, respectively. The optimum temperatures for free and immobilized enzymes were found to be 30.0 and 35.0°C, respectively. The maximum reaction rate (Vmax) and the Michaelis-Menten constant (Km) were investigated for the free and immobilized enzyme. The storage stability of acetylcholinesterase was increased when immobilized onto the novel PEI-coated silica nanoparticles. The reuse numbers of immobilized enzyme were also studied. These hybrid nanoparticles are desirable as carriers for biomedical applications.

  16. Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

    NASA Astrophysics Data System (ADS)

    Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

    2009-06-01

    Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 °C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG6000 and 0.062:1 molar ratio of PEG to FeCl2·4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

  17. Enhanced growth of lactobacilli in soymilk upon immobilization on agrowastes.

    PubMed

    Teh, Sue-Siang; Ahmad, Rosma; Wan-Abdullah, Wan-Nadiah; Liong, Min-Tze

    2010-04-01

    Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. The objective of this study was to evaluate the effects of agrowastes from durian (Durio zibethinus), cempedak (Artocarpus champeden), and mangosteen (Garcinia mangostana) as immobilizers for lactobacilli grown in soymilk. Rinds from the agrowastes were separated from the skin, dried, and ground (150 microm) to form powders and used as immobilizers. Scanning electron microscopy revealed that lactobacilli cells were attached and bound to the surface of the immobilizers. Immobilized cells of Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and L. bulgaricus FTCC 0411 were inoculated into soymilk, stored at room temperature (25 degrees C) and growth properties were evaluated over 168 h. Soymilk inoculated with nonimmobilized cells was used as the control. Utilization of substrates, concentrations of lactic and acetic acids, and changes in pH were evaluated in soymilk over 186 h. Immobilized lactobacilli showed significantly better growth (P < 0.05) compared to the control, accompanied by higher production of lactic and acetic acids in soymilk. Soymilk containing immobilized cells showed greater reduction of soy sugars such as stachyose, raffinose, sucrose, fructose, and glucose compared to the control (P < 0.05).

  18. Enhanced stability of catalase covalently immobilized on functionalized titania submicrospheres.

    PubMed

    Wu, Hong; Liang, Yanpeng; Shi, Jiafu; Wang, Xiaoli; Yang, Dong; Jiang, Zhongyi

    2013-04-01

    In this study, a novel approach combing the chelation and covalent binding was explored for facile and efficient enzyme immobilization. The unique capability of titania to chelate with catecholic derivatives at ambient conditions was utilized for titania surface functionalization. The functionalized titania was then used for enzyme immobilization. Titania submicrospheres (500-600 nm) were synthesized by a modified sol-gel method and functionalized with carboxylic acid groups through a facile chelation method by using 3-(3,4-dihydroxyphenyl) propionic acid as the chelating agent. Then, catalase (CAT) was covalently immobilized on these functionalized titania submicrospheres through 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. The immobilized CAT retained 65% of its free form activity with a loading capacity of 100-150 mg/g titania. The pH stability, thermostability, recycling stability and storage stability of the immobilized CAT were evaluated. A remarkable enhancement in enzyme stability was achieved. The immobilized CAT retained 90% and 76% of its initial activity after 10 and 16 successive cycles of decomposition of hydrogen peroxide, respectively. Both the Km and the Vmax values of the immobilized CAT (27.4 mM, 13.36 mM/min) were close to those of the free CAT (25.7 mM, 13.46 mM/min).

  19. Stablization and immobilization of excess Russian weapons origin plutonium

    SciTech Connect

    Jardine, L.J.; Borisov, G.B.; Mansourov, O.A.

    1998-04-10

    This paper summarizes a strategy, logic, and framework for the development of a capability for immobilizing excess Russian weapons origin plutonium by the year 2004. We describe the initial activities underway in Russia and a schedule to implement the strategy. These activities include engineering feasibility studies of the select facilities at the Mayak and Krasnoyarsk industrial sites, and research and development studies on plutonium glass and ceramic immobilization forms at several Russian institutes.

  20. Comparison study on photocatalytic oxidation of pharmaceuticals by TiO2-Fe and TiO2-reduced graphene oxide nanocomposites immobilized on optical fibers.

    PubMed

    Lin, Lu; Wang, Huiyao; Jiang, Wenbin; Mkaouar, Ahmed Radhi; Xu, Pei

    2017-03-08

    Incorporating reduced graphene oxide (rGO) or Fe(3+) ions in TiO2 photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO2-Fe and TiO2-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO2-rGO and TiO2-Fe nanocomposites. Doping Fe into TiO2 particles (2.40eV) could reduce more band gap energy than incorporating rGO (2.85eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO2 decreased significantly the intensity of TiO2 photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO2-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO2-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO2-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO2-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic activity.

  1. Antimony (Sb) and lead (Pb) in contaminated shooting range soils: Sb and Pb mobility and immobilization by iron based sorbents, a field study.

    PubMed

    Okkenhaug, Gudny; Grasshorn Gebhardt, Karl-Alexander; Amstaetter, Katja; Bue, Helga Lassen; Herzel, Hannes; Mariussen, Espen; Rossebø Almås, Åsgeir; Cornelissen, Gerard; Breedveld, Gijs D; Rasmussen, Grete; Mulder, Jan

    2016-04-15

    Small-arm shooting ranges often receive a significant input of lead (Pb), copper (Cu) and antimony (Sb) from ammunition. The goal of the present study was to investigate the mobility, distribution and speciation of Pb and Sb pollution under field conditions in both untreated and sorbent-amended shooting range soil. Elevated Sb (19-349μgL(-1)) and Pb (7-1495μgPbL(-1)) concentrations in the porewater of untreated soil over the four-year test period indicated a long-term Sb and Pb source to the adjacent environment in the absence of remedial measures. Mixing ferric oxyhydroxide powder (CFH-12) (2%) together with limestone (1%) into the soil resulted in an average decrease of Sb and Pb porewater concentrations of 66% and 97%, respectively. A similar reduction was achieved by adding 2% zerovalent iron (Fe°) to the soil. The remediation effect was stable over the four-year experimental period indicating no remobilization. Water- and 1M NH4NO3-extractable levels of Sb and Pb in field soil samples indicated significant immobilization by both treatments (89-90% for Sb and 89-99% for Pb). Results from sequential extraction analysis indicate fixation of Sb and Pb in less accessible fractions like amorphous iron oxides or even more crystalline and residual mineral phases, respectively. This work shows that amendment with Fe-based sorbents can be an effective method to reduce the mobility of metals both in cationic and anionic form in polluted shooting range soil.

  2. Nanoporous Gold as a Solid Support for Protein Immobilization for the Development of Immunoassays, and for Biomolecular Interaction Studies

    NASA Astrophysics Data System (ADS)

    Pandey, Binod Prasad

    Nanoporous gold (NPG) is a versatile material of high surface area to volume ratio that can be readily modified with self-assembled monolayers of alkanethiols to which biomolecules can be linked. NPG presents new opportunities for the development of immunoassays, and for the development of carbohydrate based assays. This thesis explores the use of NPG as a support for self-assembled monolayers, their linkage to antibody-enzyme conjugates for immunoassay development, and for the study and application of carbohydrate-protein interactions. Direct kinetic electrochemical immunoassays were developed on NPG for prostate specific antigen (PSA) and carcinoembryonic antigen (CEA). The decrease in enzymatic conversion of p-aminophenylphosphate to p-aminophenol, by alkaline phosphatase conjugated to an antibody, due to steric hindrance caused by the presence of antigen on antibody, was observed as a drop in peak current in square-wave voltammetry. Detection limit of these assays was 0.075 ng mL -1 and 0.015 ng mL-1 for PSA and CEA, respectively. Similarly, the linear range of determination of these biomarkers extended up to 30 ng mL-1 and 10 ng mL-1 for PSA and CEA, respectively. Minimal interference was observed using newborn calf serum as a substitute for the human serum matrix. A rapid and sensitive enzyme linked lectinsorbant assay was also developed for the study of glycoprotein-lectin interactions on the NPG surface. Self-assembled monolayers of alkanethiols on NPG were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Similarly, the applicability of this surface for the formation of carbohydrate monolayers and its application for lectin carbohydrate interactions was also studied. Pure and mixed SAMs of 8-mercaptooctyl β-D-mannopyranoside (αMan-C8-SH) and α-D-Gal-(1→4)-β-D-Gal-(1α)-D-Glc-1-O-mercaptooctane (Gb3-C8-SH) with alkanethiols having varying tail groups were prepared. Binding affinity and binding kinetics of concanavalin A

  3. 1-step versus 2-step immobilization of alkaline phosphatase and bone morphogenetic protein-2 onto implant surfaces using polydopamine.

    PubMed

    Nijhuis, Arnold W G; van den Beucken, Jeroen J J P; Boerman, Otto C; Jansen, John A; Leeuwenburgh, Sander C G

    2013-08-01

    Immobilization of biomolecules onto implant surfaces is highly relevant in many areas of biomaterial research. Recently, a 2-step immobilization procedure was developed for the facile conjugation of biomolecules onto various surfaces using self-polymerization of dopamine into polydopamine. In the current study, a 1-step polydopamine-based approach was applied for alkaline phosphatase (ALP) and bone morphogenetic protein-2 (BMP-2) immobilization, and compared to the conventional 2-step polydopamine-based immobilization and plain adsorption. To this end, ALP and BMP-2 were immobilized onto titanium and polytetrafluoroethylene (PTFE) substrates. The absolute quantity and biological activity of immobilized ALP were assessed quantitatively to compare the three types of immobilization. Plain adsorption of both ALP and BMP-2 was inferior to both polydopamine-based immobilization approaches. ALP was successfully immobilized onto titanium and PTFE surfaces via the 1-step approach, and the immobilized ALP retained its enzymatic activity. Using the 1-step approach, the amount of immobilized ALP was increased twofold to threefold compared to the conventional 2-step immobilization process. In contrast, more BMP-2 was immobilized using the conventional 2-step immobilization approach. Retention of ALP and BMP-2 was measured over a period of 4 weeks and was found to be similar for the 1-step and 2-step methods and far superior to the retention of adsorbed biomolecules due to the formation of covalent linkages between catechol moieties and immobilized proteins. The biological behavior of ALP and BMP-2 coatings immobilized using polydopamine (1- and 2-step) as well as adsorption was assessed by culturing rat bone marrow cells, which revealed that the cell responses to the various experimental groups were not statistically different. In conclusion, the 1-step polydopamine-based immobilization method was shown to be more efficient for immobilization of ALP, whereas the conventional 2

  4. Potentiometric biosensor for determination of urea in milk using immobilized Arthrobacter creatinolyticus urease.

    PubMed

    Ramesh, Rajendran; Puhazhendi, Puhazhselvan; Kumar, Jitendra; Gowthaman, Marichetti Kuppuswami; D'Souza, Stanislaus Francis; Kamini, Numbi Ramudu

    2015-04-01

    The extracellular urease from Arthrobacter creatinolyticus was partially purified by ammonium sulfate precipitation and immobilized on PAN [poly(acrylonitrile-methylmethacrylate-sodium vinylsulfonate)] membrane. The urease immobilized PAN membrane exhibited an activity of 97.92U/cm(2) under the optimum conditions of 1.0% enzyme concentration, 15% glutaraldehyde, 24h immobilization time and temperature of 4°C. The changes in surface morphology of the membrane after immobilization were studied by SEM and ATR-FTIR analysis. Immobilized membrane was associated with potentiometric electrode for calibration of biosensor and the results showed a linear response for wide range of urea concentration from 1 to 100mM. The immobilized urease had good storage stability for a period of 70days at 4°C and could be effectively reused for 13cycles. Urease immobilized membrane was also employed in analysis of urea spiked milk samples.

  5. N-15 NMR study of the immobilization of 2,4- and 2,6-dinitrotoluene in aerobic compost.

    PubMed

    Thorn, Kevin A; Pennington, Judith C; Kennedy, Kay R; Cox, Larry G; Hayes, Charolett A; Porter, Beth E

    2008-04-01

    Large-scale aerobic windrow composting has been used to bioremediate washout lagoon soils contaminated with the explosives TNT (2,4,6-trinitrotoluene) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) at several sites within the United States. We previously used 15N NMR to investigate the reduction and binding of T15NT in aerobic bench-scale reactors simulating the conditions of windrow composting. These studies have been extended to 2,4-dinitrotoluene (2,4DNT) and 2,6-dinitrotoluene (2,6DNT), which, as impurities in TNT, are usually presentwherever soils have been contaminated with TNT. Liquid-state 15N NMR analyses of laboratory reactions between 4-methyl-3-nitroaniline-15N, the major monoamine reduction product of 2,4DNT, and the Elliot soil humic acid, both in the presence and absence of horseradish peroxidase, indicated that the amine underwent covalent binding with quinone and other carbonyl groups in the soil humic acid to form both heterocyclic and non-heterocyclic condensation products. Liquid-state 15N NMR analyses of the methanol extracts of 20 day aerobic bench-scale composts of 2,4-di-15N-nitrotoluene and 2,6-di-15N-nitrotoluene revealed the presence of nitrite and monoamine, but not diamine, reduction products, indicating the occurrence of both dioxygenase enzyme and reductive degradation pathways. Solid-state CP/MAS 15N NMR analyses of the whole composts, however, suggested that reduction to monoamines followed by covalent binding of the amines to organic matter was the predominant pathway.

  6. N-15 NMR study of the immobilization of 2,4- and 2,6-dinitrotoluene in aerobic compost

    USGS Publications Warehouse

    Thorn, K.A.; Pennington, J.C.; Kennedy, K.R.; Cox, L.G.; Hayes, C.A.; Porter, B.E.

    2008-01-01

    Large-scale aerobic windrow composting has been used to bioremediate washout lagoon soils contaminated with the explosives TNT (2,4,6- trinitrotoluene) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) at several sites within the United States. We previously used 15N NMR to investigate the reduction and binding of T15NT in aerobic bench -scale reactors simulating the conditions of windrow composting. These studies have been extended to 2,4-dinitrotoluene (2,4DNT) and 2,6-dinitrotoluene (2,6DNT), which, as impurities in TNT, are usually present wherever soils have been contaminated with TNT. Liquid-state 15N NMR analyses of laboratory reactions between 4-methyl-3-nitroaniline-15N, the major monoamine reduction product of 2,4DNT, and the Elliot soil humic acid, both in the presence and absence of horseradish peroxidase, indicated that the amine underwent covalent binding with quinone and other carbonyl groups in the soil humic acid to form both heterocyclic and non-heterocyclic condensation products. Liquid-state 15N NMR analyses of the methanol extracts of 20 day aerobic bench-scale composts of 2,4-di-15N-nitrotoluene and 2,6-di-15N-nitrotoluene revealed the presence of nitrite and monoamine, but not diamine, reduction products, indicating the occurrence of both dioxygenase enzyme and reductive degradation pathways. Solid-state CP/MAS 15N NMR analyses of the whole composts, however, suggested that reduction to monoamines followed by covalent binding of the amines to organic matter was the predominant pathway. ?? 2008 American Chemical Society.

  7. Immunosuppressive agent leflunomide: a SWNTs-immobilized dihydroortate dehydrogenase inhibitory effect and computational study of its adsorption properties on zigzag single walled (6,0) carbon and boron nitride nanotubes as controlled drug delivery devices.

    PubMed

    Raissi, Heidar; Mollania, Fariba

    2014-06-02

    Leflunomide [HWA 486 or RS-34821, 5-methyl-N-(4trifluoromethylphenyl)-4-isoxazole carboximide] is an immunosuppressive agent effective in the treatment of rheumatoid arthritis. Dihydroortate dehydrogenase (DHODH, EC 1.3.3.1) immobilization on the nanotubes was carried out and biochemical characterization of free and immobilized enzyme was determined. In comparison with free enzyme, the immobilized DHODH showed improved stability and reusability for investigation of inhibition pattern of drugs such as leflunomide. The experimental data showed that, DHODH was inhibited by the active metabolite of leflunomide (RS-61980) with a Ki and KI of 0.82 and 0.06 mM, respectively. Results exhibited mixed-type inhibition kinetics towards dihydroorotate as a substrate in the free and immobilized enzyme. Furthermore, the behavior of anticancer drug leflunomide adsorbed on the external surface of zigzag single walled (6,0) carbon and boron nitride nanotubes (SWCNT and SWBNNT) was studied by means of DFT calculations at the B3LYP/6-31G(*) level of theory. The larger adsorption energies and charges transfer showed that the adsorption of leflunomide onto SWBNNT is more stable than that the adsorption of leflunomide onto SWCNT. Frontier molecular orbitals (HOMO and LUMO) suggest that adsorption of leflunomide onto SWBNNT behave as charge transfer compounds with leflunomide as an electron donor and SWBNNT as an electron acceptor. Thus, nanotubes (NTs) have been proposed and actively explored as multipurpose innovative carriers for drug delivery and diagnostic application. The AIM theory has been also applied to analyze the properties of the bond critical points: their electron densities and their laplacians. Also, the natural bond orbital (NBO) calculations were performed to derive natural atomic orbital occupancies, and partial charges of the interacting atoms in the equilibrium tube-molecule distance.

  8. Treating Wastewater With Immobilized Enzymes

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.

    1991-01-01

    Experiments show enzymes are immobilized on supporting materials to make biocatalyst beds for treatment of wastewater. With suitable combination of enzymes, concentrations of various inorganic and organic contaminants, including ammonia and urea, reduced significantly.

  9. Synthesis of bi-metallic Au-Ag nanoparticles loaded on functionalized MCM-41 for immobilization of alkaline protease and study of its biocatalytic activity

    NASA Astrophysics Data System (ADS)

    Sadjadi, M. S.; Farhadyar, N.; Zare, K.

    2009-10-01

    In this work, Au-Ag nanoparticles (Au-Ag-bi-MNPs) have been prepared on amine functionalized Si-MCM-41 (NH 2-Si-MCM-41) particles through a reduction of AgNO 3 and HAuCl 4 by NaBH 4 at ambient conditions. Au-Ag-bi-MNPs loaded on the NH2-Si-MCM-41, provide a good biocompatible surface for immobilization of the enzyme alkaline protease. This immobilization, presumably due to bonding between core shell nanoparticles and OH in serine 183 in alkaline protease seems to be of an ionic exchange nature. We found that the alkaline protease immobilized on the Au-Ag-bi-MNPs/Si-MCM-41 is an active biocatalyst, stable at different pH and temperature. The bio catalytic activity of free alkaline protease in solution was 64 U/mg (Units per milligram), whereas that of the alkaline protease immobilized on Au-Ag-bi-MNPs/Si-MCM-41 was 75 U/mg. This improvement of the biocatalytic activity may be due to a really increased activity per molecule of immobilized enzyme or to a purification of the enzyme. The alkaline protease molecules immobilized on the (Au-Ag)/ NH 2-MCM-41 surface retained as much as 80% of the catalytic activity recorded at pH=8, and showed significant catalytic activity of alkaline protease in the bioconjugate material. The biocatalytic materials were easily separated from the reaction medium by mild centrifugation and exhibits excellent reuse and stability characteristics over four successive cycles. The optimum temperature ranged from 35 ∘C-55 ∘C and pH=8 for bioactivity of the alkaline protease in the assembly system was observed to be higher than that of the free enzyme in solution. The enzyme biocatalytic activity was monitored by UV-visible spectroscopy. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and dispersive analysis of X-RAY (EDAX) were used to characterize the size and morphology of the prepared materials.

  10. Cellulase immobilization on magnetic nanoparticles encapsulated in polymer nanospheres.

    PubMed

    Lima, Janaina S; Araújo, Pedro H H; Sayer, Claudia; Souza, Antonio A U; Viegas, Alexandre C; de Oliveira, Débora

    2017-04-01

    Immobilization of cellulases on magnetic nanoparticles, especially magnetite nanoparticles, has been the main approach studied to make this enzyme, economically and industrially, more attractive. However, magnetite nanoparticles tend to agglomerate, are very reactive and easily oxidized in air, which has strong impact on their useful life. Thus, it is very important to provide proper surface coating to avoid the mentioned problems. This study aimed to investigate the immobilization of cellulase on magnetic nanoparticles encapsulated in polymeric nanospheres. The support was characterized in terms of morphology, average diameter, magnetic behavior and thermal decomposition analyses. The polymer nanospheres containing encapsulated magnetic nanoparticles showed superparamagnetic behavior and intensity average diameter about 150 nm. Immobilized cellulase exhibited broader temperature stability than in the free form and great reusability capacity, 69% of the initial enzyme activity was maintained after eight cycles of use. The magnetic support showed potential for cellulase immobilization and allowed fast and easy biocatalyst recovery through a single magnet.

  11. The Boxer's Fracture: Splint Immobilization Is Not Necessary.

    PubMed

    Dunn, John C; Kusnezov, Nicholas; Orr, Justin D; Pallis, Mark; Mitchell, Justin S

    2016-05-01

    Fractures of the fifth metacarpal neck, or boxer's fractures, are common, particularly among young men. Because of the high frequency of this injury, there is a considerable range of treatment options. The purpose of this systematic review was to determine whether reduction and splint or cast immobilization is necessary for fractures of the fifth metacarpal neck. The authors conducted a systematic review of all published studies that randomized these fractures to cast immobilization vs treatment with soft wrap without reduction. Cast immobilization is not superior to soft wrap without reduction in most cases. The study found that reduction and cast immobilization is not necessary for boxer's fractures. [Orthopedics. 2016; 39(3):188-192.].

  12. Immobilization of Polymeric Luminophor on Nanoparticles Surface

    NASA Astrophysics Data System (ADS)

    Bolbukh, Yuliia; Podkoscielna, Beata; Lipke, Agnieszka; Bartnicki, Andrzej; Gawdzik, Barbara; Tertykh, Valentin

    2016-04-01

    Polymeric luminophors with reduced toxicity are of the priorities in the production of lighting devices, sensors, detectors, bioassays or diagnostic systems. The aim of this study was to develop a method of immobilization of the new luminophor on a surface of nanoparticles and investigation of the structure of the grafted layer. Monomer 2,7-(2-hydroxy-3-methacryloyloxypropoxy)naphthalene (2,7-NAF.DM) with luminophoric properties was immobilized on silica and carbon nanotubes in two ways: mechanical mixing with previously obtained polymer and by in situ oligomerization with chemisorption after carrier's modification with vinyl groups. The attached polymeric (or oligomeric) surface layer was studied using thermal and spectral techniques. Obtained results confirm the chemisorption of luminophor on the nanotubes and silica nanoparticles at the elaborated synthesis techniques. The microstructure of 2,7-NAF.DM molecules after chemisorption was found to be not changed. The elaborated modification approach allows one to obtain nanoparticles uniformly covered with polymeric luminophor.

  13. Immobilizing PEO-PPO-PEO triblock copolymers on hydrophobic surfaces and its effect on protein and platelet: a combined study using QCM-D and DPI.

    PubMed

    Jin, Jing; Huang, Fujian; Hu, Yu; Jiang, Wei; Ji, Xiangling; Liang, Haojun; Yin, Jinghua

    2014-11-01

    Dual polarization interferometry was used to monitor the immobilization dynamics of four Pluronics on hydrophobic surfaces and to elucidate the effect of Pluronic conformation on protein adsorption. The proportion of hydrophobic chain segments and not the length of the hydrophobic chain can influence the chain densities of the Pluronics. The immobilized densities of the Pluronics resulted from competition between the hydration of polyethylene oxide (PEO) in the aqueous solution and the hydrophobic interaction of polypropylene oxide on the substrate. P-123 obtained the largest graft mass (2.89±0.25 ng/mm2) because of the dominant effect of hydrophobic interactions. Hydrophobic segments of P-123 were anchored slowly and step-wise on the C18 substrate. P-123 exhibited the largest hydrophobic chain segment proportion (propylene oxide/ethylene oxide=3.63) and formed a brush chain conformation, indicating excellent protein and platelet resistance. The result of quartz crystal microbalance with dissipation further confirmed that the PEO conformation in P-123 on the substrate exhibited a relatively extended brush chain, and that L-35 showed relatively loose and pancake-like structures. The PEO in P-123 regulated the conformation to maintain the native conformation and resist the adsorption of bovine serum albumin (BSA). Thus, the hemocompatibilities of the immobilized Pluronics were influenced by the proportion of hydrophobic chain segments and their PEO conformations.

  14. Heparin-conjugated gelatin as a growth factor immobilization scaffold.

    PubMed

    Nakamura, Shintaro; Kubo, Takafumi; Ijima, Hiroyuki

    2013-05-01

    Tissue engineering requires growth factors, cells and a scaffold to permit effective tissue regeneration. This study aimed to develop a scaffold with a focus on immobilizing growth factors within gelatin. We focused on the extracellular matrix and developed a heparin-conjugated gelatin (Hep-gela). Conjugation was confirmed using the alcian blue assay and X-ray diffraction patterns. The mechanical strength and stability of the Hep-gela gel in protease solution were improved compared with collagen gel. Hep-gela was able to immobilize vascular endothelial growth factor (VEGF) even in the presence of albumin, with an efficiency of 54.2%. Immobilized VEGF promoted proliferation of human umbilical vein endothelial cells. Hep-gela-immobilized VEGF maintained its native biological activity. In summary, Hep-gela has the potential to become an effective material in the field of regenerative medicine.

  15. Immobilization of enzyme on dimethyl-aminated nylon gels

    SciTech Connect

    Miyama, H.; Kawate, M.; Nosaka, Y.

    1985-10-01

    Miyama and co-workers have reported that dimethyl-aminated Nylon is a good material for the immobilization of enzyme after being quaternized. Also, they found a good correlation between the apparent Michaelis constant of the immobilized enzyme and the diffusion constant of the substrate in the matrix, and that between activity of the immobilized enzyme and interfacial free energy of the matrix. In their experiments, Nylon films of low degree of dimethylamination were used. In the present study, dimethylaminated Nylon of high degree of dimethylamination was quaternized by cationic oligomers having two functional groups. Thus, hydrogels were obtained, where the degree of cross-linking and the density of cation could be varied by changing the feeding amount and the length of cross-linking oligomers. These gels were then tested for the immobilization of urease and glucose oxidase. 9 references.

  16. Acid phosphatase and protease activities in immobilized rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Troup, J. P.; Fitts, R. H.

    1982-01-01

    The effect of hind-limb immobilization on selected Iysosomal enzyme activities was studied in rat hing-limb muscles composed primarily of type 1. 2A, or 2B fibers. Following immobilization, acid protease and acid phosphatase both exhibited signifcant increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.

  17. Effect of kinesthetic illusion induced by visual stimulation on muscular output function after short-term immobilization.

    PubMed

    Inada, Toru; Kaneko, Fuminari; Hayami, Tatsuya

    2016-04-01

    Kinesthetic illusions by visual stimulation (KiNVIS) enhances corticomotor excitability and activates motor association areas. The purpose of this study was to investigate the effect of KiNVIS induction on muscular output function after short-term immobilization. Thirty subjects were assigned to 3 groups: an immobilization group, with the left hand immobilized for 12h (immobilization period); an illusion group, with the left hand immobilized and additionally subjected to KiNVIS of the immobilized part during the immobilization period; and a control group with no manipulation. The maximum voluntary contraction (MVC), fluctuation of force (force fluctuation) during a force modulation task, and twitch force were measured both before (pre-test) and after (post-test) the immobilization period. Data were analyzed by performing two-way (TIME×GROUP) repeated measures ANOVA. The MVC decreased in the immobilization group only (pre-test; 37.8±6.1N, post-test; 32.8±6.9N, p<0.0005) after the immobilization period. The force fluctuation increased only in the immobilization group (pre-test; 2.19±0.54%, post-test; 2.78±0.87%, p=0.007) after the immobilization period. These results demonstrate that induction of KiNVIS prevents negative effect on MVC and force fluctuation after 12h of immobilization.

  18. Status of plutonium ceramic immobilization processes and immobilization forms

    SciTech Connect

    Ebbinghaus, B.B.; Van Konynenburg, R.A.; Vance, E.R.; Jostsons, A.

    1996-05-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.

  19. Immobilization of arginase and its application in an enzymatic chromatographic column: thermodynamic studies of nor-NOHA/arginase binding and role of the reactive histidine residue.

    PubMed

    Bagnost, Teddy; Guillaume, Yves-Claude; Thomassin, Mireille; Robert, Jean-François; Berthelot, Alain; Xicluna, Alain; André, Claire

    2007-09-01

    A biochromatographic approach is developed to measure for the first time changes in enthalpy, heat capacity change and protonation for the binding of nor-NOHA to arginase in a wide temperature range. For this, the arginase enzyme was immobilized on a chromatographic support. It was established that this novel arginase column was stable during an extended period of time. The affinity of nor-NOHA to arginase is high and changes slightly with the pH, because the number of protons linked to binding is low. The determination of the enthalpy change at different pH values suggested that the protonated group in the nor-NOHA-arginase complex exhibits a heat protonation of approximately -33 kJ/mol. This value agrees with the protonation of an imidazole group. Our result confirmed that active-site residue Hist 141 is protonated as imidazolium cation. Hist 141 can function as a general acid to protonate the leaving amino group of L-ornithine during catalysis. The thermodynamic data showed that nor-NOHA-arginase binding, for low temperature (<15 degrees C), is enthalpically unfavourable and being dominated by a positive entropy change. This result suggests that dehydration at the binding interface and charge-charge interactions contribute to the nor-NOHA-arginase complex formation. The temperature dependence of the free energy of binding is weak because of the enthalpy-entropy compensation caused by a large heat capacity change, DeltaC(p)=-2.43 kJ/mol/K, of arginase. Above 15 degrees C, the thermodynamic data DeltaH and DeltaS became negative due to van der Waals interactions and hydrogen bonding which are engaged at the complex interface confirming strong enzyme-inhibitor hydrogen bond networks. As well, by the use of these thermodynamic data and known correlations it was clearly demonstrated that the binding of nor-NOHA to arginase produces slight conformational changes in the vicinity of the active site. Our work indicated that our biochromatographic approach could soon

  20. Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis

    NASA Astrophysics Data System (ADS)

    Petkova, Galina A.; Záruba, Кamil; Žvátora, Pavel; Král, Vladimír

    2012-06-01

    In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective ( ee > 99%) synthesis of ( S)-7-hydroxy-2-tetralol.

  1. Immobilization of enzyme on a polymer surface

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Cheng, Kenneth Chun Kuen; Schroeder, McKenna; Yang, Pei; Marsh, E. Neil G.; Lahann, Joerg; Chen, Zhan

    2016-06-01

    We successfully immobilized enzymes onto polymer surfaces via covalent bonds between cysteine groups of the enzyme and dibromomaleimide functionalities present at the polymer surface. In this work, we used nitroreductase (NfsB) as a model enzyme molecule. The polymers were prepared by chemical vapor deposition (CVD) polymerization, resulting in surfaces with dibromomaleimide groups. NfsB variants were engineered so that each NfsB molecule only has one cysteine group on the enzyme surface. Two different NfsB constructs were studied, with cysteines at the positions of H360 and V424, respectively. A combination of sum frequency generation (SFG) vibrational and attenuated total reflectance Fourier transformed infrared (ATR-FTIR) spectroscopies were used to deduce the orientation of the immobilized enzymes on the surface. It was found that the orientation of the immobilized enzymes is controlled by the position of the cysteine residue in the protein. The NfsB H360C construct exhibited a similar orientational behavior on the polymer surface as compared to that on the self-assembled monolayer surface, but the NsfB V424C construct showed markedly different orientations on the two surfaces.

  2. Antibody immobilization on a nanoporous aluminum surface for immunosensor development

    NASA Astrophysics Data System (ADS)

    Chai, Changhoon; Lee, Jooyoung; Park, Jiyong; Takhistov, Paul

    2012-12-01

    A method of antibody (Ab) immobilization on a nanoporous aluminum surface for an electrochemical immunosensor is presented. To achieve good attachment and stability of Ab on an aluminum surface, aluminum was silanized with 3-aminopropyltryethoxysilane (APTES), and then covalently cross-linked to self-assembled layers (SALs) of APTES. Both the APTES concentration and the silanization time affected the formation of APTES-SALs as Ab immobilization. The formation of APTES-SALs was confirmed using the water contact angle on the APTES-SALs surface. The reactivity of APTES-SALs with Ab was investigated by measuring the fluorescence intensity of fluorescein isothiocyanate-labeled Ab-immobilized on the aluminum surface. Silanization of aluminum in 2% APTES for 4 h resulted in higher water contact angles and greater amounts of immobilized Ab than other APTES concentrations or silanization times. More Ab was immobilized on the nanoporous surface than on a planar aluminum surface. Electrochemical immunosensors developed on the nanoporous aluminum via the Ab immobilization method established in this study responded functionally to the antigen concentration in the diagnostic solution.

  3. Immobilization of pectin depolymerising polygalacturonase using different polymers.

    PubMed

    Ur Rehman, Haneef; Aman, Afsheen; Nawaz, Muhammad Asif; Karim, Asad; Ghani, Maria; Baloch, Abdul Hameed; Ul Qader, Shah Ali

    2016-01-01

    Polygalacturonase catalyses the hydrolysis of pectin substances and widely has been used in food and textile industries. In current study, different polymers such as calcium alginate beads, polyacrylamide gel and agar-agar matrix were screened for the immobilization of polygalacturonase through entrapment technique. Polyacrylamide gel was found to be most promising one and gave maximum (89%) immobilization yield as compared to agar-agar (80%) and calcium alginate beads (46%). The polymers increased the reaction time of polygalacturonase and polymers entrapped polygalacturonases showed maximum pectinolytic activity after 10 min of reaction as compared to free polygalacturonase which performed maximum activity after 5.0 min of reaction time. The temperature of polygalacturonase for maximum enzymatic activity was increased from 45°C to 50°C and 55°C when it was immobilized within agar-agar and calcium alginate beads, respectively. The optimum pH (pH 10) of polygalacturonase was remained same when it was immobilized within polyacrylamide gel and calcium alginate beads, but changed from pH 10 to pH 9.0 after entrapment within agar-agar. Thermal stability of polygalacturonase was improved after immobilization and immobilized polygalacturonases showed higher tolerance against different temperatures as compared to free enzyme. Polymers entrapped polygalacturonases showed good reusability and retained more than 80% of their initial activity during 2nd cycles.

  4. New immobilized cell system with protection against toxic solvents

    SciTech Connect

    Tanaka, H.; Harada, S.; Kurosawa, H.; Yajima, M.

    1987-01-01

    A new immobilized cell system providing protection against toxic solvents was investigated so that normal fermentations could be carried out in a medium containing toxic solvents. The system consists of immobilized growing cells in Ca-alginate gel beads to which vegetable oils, which are inexpensive absorbents of solvents, had been added. The ethanol fermentation of Saccharomyces cerevisiae ATCC 26603 was used as a model fermentation to study the protection afforded by the system against solvent toxicities. The fermentation was inhibited by solvents such as 2-octanol, benzene, toluene, and phenol. Ethanol production of one batch was not finished even after 35 h using immobilized growing yeast cells in conventional Ca-alginate gel beads in an ethanol production medium (5% glucose) containing 0.1% 2-octanol, which is used as a solvent for liquid-liquid extraction and is one of the most toxic solvents in our experiments. With the new immobilized growing cell system using vegetable oils, however, four repeated batch fermentations were completed in 35 h. Castor oil provided even more protection than soy bean, olive, and tung oils, and it was possible to complete six repeated batches in 35 h. The immobilized cell system with vegetable oils also provided protection against other toxic solvents such as benzene and toluene. A possible mechanism for the protective function of the new immobilized cell system is discussed.

  5. Immobilization of Mucor miehei Lipase onto Macroporous Aminated Polyethersulfone Membrane for Enzymatic Reactions

    PubMed Central

    Handayani, Nurrahmi; Loos, Katja; Wahyuningrum, Deana; Buchari; Zulfikar, Muhammad Ali

    2012-01-01

    Immobilization of enzymes is one of the most promising methods in enzyme performance enhancement, including stability, recovery, and reusability. However, investigation of suitable solid support in enzyme immobilization is still a scientific challenge. Polyethersulfone (PES) and aminated PES (PES–NH2) were successfully synthesized as novel materials for immobilization. Membranes with various pore sizes (from 10–600 nm) based on synthesized PES and PES–NH2 polymers were successfully fabricated to be applied as bioreactors to increase the immobilized lipase performances. The influence of pore sizes, concentration of additives, and the functional groups that are attached on the PES backbone on enzyme loading and enzyme activity was studied. The largest enzyme loading was obtained by Mucor miehei lipase immobilized onto a PES–NH2 membrane composed of 10% of PES–NH2, 8% of dibutyl phthalate (DBP), and 5% of polyethylene glycol (PEG) (872.62 µg/cm2). Hydrolytic activity of the immobilized lipases indicated that the activities of biocatalysts are not significantly decreased by immobilization. From the reusability test, the lipase immobilized onto PES–NH2 showed a better constancy than the lipase immobilized onto PES (the percent recovery of the activity of the lipases immobilized onto PES–NH2 and PES are 97.16% and 95.37%, respectively), which indicates that this novel material has the potential to be developed as a bioreactor for enzymatic reactions. PMID:24958172

  6. The Efficacy of the Rapid Form Cervical Vacuum Immobilizer in Cervical Spine Immobilization of the Equipped Football Player

    PubMed Central

    Ransone, Jack; Kersey, Robert; Walsh, Katie

    2000-01-01

    Objective: To determine the effectiveness of the Rapid Form Cervical Vacuum Immobilizer in controlling the cervical spine movements of a football player wearing shoulder pads and a helmet. Design and Setting: We used a 1-group, repeated-measures experimental design to radiographically assess cervical spine range of motion with and without the Rapid Form Cervical Vacuum Immobilizer. Two experimental conditions (with and without vacuum splint) were applied to 10 subjects in a repeated-measures design. Each subject was radiographed in cervical forward flexion, extension, and lateral flexion under each experimental condition. Subjects: Ten healthy male subjects without a history of cervical spine pathology or abnormality volunteered for this study. Measurements: Cervical forward flexion, extension, and lateral flexion range of motion were compared under both treatment conditions. Joint angles were determined by straightedge tangential lines drawn on the radiographs along the foramen magnum, inferior ring border of the atlas, and along the inferior tips of the 2nd through 7th vertebral bodies. The total range of motion was determined and compared with the treatment condition by multiple paired t tests. Results: The Cervical Vacuum Immobilizer limited cervical spine range of motion in forward flexion, extension, and lateral flexion. The secondary statistical analysis for the effect size determined that each group had a large effect size, indicating that the power of the experimental or vacuum splint group was high. Conclusions: We found that the Cervical Vacuum Immobilizer limited cervical spine range of motion in forward flexion, extension, and lateral flexion. The Cervical Vacuum Immobilizer can be easily placed on an injured, fully equipped football player and serves to limit cervical spine range of motion while the athlete is immobilized and transported. Future research should determine how the Cervical Vacuum Immobilizer limits range of motion with the athlete

  7. Development of a liquid chromatographic system with fluorescent detection for beta-secretase immobilized enzyme reactor on-line enzymatic studies.

    PubMed

    Mancini, Francesca; Andrisano, Vincenza

    2010-07-08

    A novel liquid chromatographic method has been developed for use in throughput screening of new inhibitors of human recombinant beta-amyloid precursor protein cleaving enzyme (hrBACE1). The approach is based on the use of an immobilized enzyme reactor (IMER) containing the target enzyme (hrBACE1-IMER) and uses fluorescence detection. The bioreactor was prepared by immobilizing hrBACE1 on an ethylendiamine (EDA) monolithic disk (CIM) and a fluorogenic peptide (M-2420) containing the beta-secretase site of the Swedish mutation of amyloid precursor protein (APP) was used as substrate. After injection into the hrBACE1-IMER system, M-2420 was enzymatically cleaved, giving rise to a fluorescent methoxycoumaryl-fragment (Rt=1.6min), which was separated from the substrate and selectively detected at lambda(exc)=320 and lambda(em)=420nm. Product and substrate were characterized by using a post monolithic C18 stationary phase coupled to an ion trap mass analyser. A calibration curve was constructed to determine the immobilized hrBACE1-IMER rate of catalysis and kinetic constants. Specificity of the enzymatic cleavage was confirmed by injecting the substrate on a blank CIM-EDA. The proposed method was validated by the determination of the inhibitory potency of five reference compounds with activities ranked over four order of magnitude (four peptidic inhibitors and a green tea polyphenol, (-)gallocatechin gallate). The obtained results were found in agreement with the data reported in literature, confirming the validity and the applicability of the hrBACE1-IMER as a tool for the fast screening of unknown inhibitors (more than 6 compounds per hour). Moreover, the hrBACE1-IMER showed high stability during the analysis, permitting its use for more than three months without affecting enzyme activity.

  8. Biodiesel production from Jatropha oil catalyzed by immobilized Burkholderia cepacia lipase on modified attapulgite.

    PubMed

    You, Qinghong; Yin, Xiulian; Zhao, Yuping; Zhang, Yan

    2013-11-01

    Lipase from Burkholderia cepacia was immobilized on modified attapulgite by cross-linking reaction for biodiesel production with jatropha oil as feedstock. Effects of various factors on biodiesel production were studied by single-factor experiment. Results indicated that the best conditions for biodiesel preparation were: 10 g jatropha oil, 2.4 g methanol (molar ratio of oil to methanol is 1:6.6) being added at 3h intervals, 7 wt% water, 10 wt% immobilized lipase, temperature 35°C, and time 24h. Under these conditions, the maximum biodiesel yield reached 94%. The immobilized lipase retained 95% of its relative activity during the ten repeated batch reactions. The half-life time of the immobilized lipase is 731 h. Kinetics was studied and the Vmax of the immobilized lipases were 6.823 mmol L(-1). This immobilized lipase catalyzed process has potential industrial use for biodiesel production to replace chemical-catalyzed method.

  9. Hydrolysis of triacetin catalyzed by immobilized lipases: effect of the immobilization protocol and experimental conditions on diacetin yield.

    PubMed

    Hernandez, Karel; Garcia-Verdugo, Eduardo; Porcar, Raul; Fernandez-Lafuente, Roberto

    2011-05-06

    The effect of the immobilization protocol and some experimental conditions (pH value and presence of acetonitrile) on the regioselective hydrolysis of triacetin to diacetin catalyzed by lipases has been studied. Lipase B from Candida antarctica (CALB) and lipase from Rhizomucor miehei (RML) were immobilized on Sepabeads (commercial available macroporous acrylic supports) activated with glutaraldehyde (covalent immobilization) or octadecyl groups (adsorption via interfacial activation). All the biocatalysts accumulated diacetin. Covalently immobilized RML was more active towards rac-methyl mandelate than the adsorbed RML. However, this covalent RML preparation presented the lowest activity towards triacetin. For this reason, this preparation was discarded as biocatalyst for this reaction. At pH 7, acyl migration occurred giving a mixture of 1,2 and 1,3 diacetin, but at pH 5.5, only 1,2 diacetin was produced. Yields were improved at acidic pH values and in the presence of 20% acetonitrile (to over 95%). RML immobilized on octadecyl Sepabeads was proposed as optimal preparation, mainly due to its higher specific activity. Each enzyme preparation presented very different properties. Moreover, changes in the reaction conditions affected the various immobilized enzymes in a different way.

  10. Bioluminescent Reaction by Immobilized Luciferase

    NASA Astrophysics Data System (ADS)

    Tanaka, Ryuta; Takahama, Eriko; Iinuma, Masataka; Ikeda, Takeshi; Kadoya, Yutaka; Kuroda, Akio

    We have investigated an effect of immobilization of luciferase molecules at the optical fiber end on a bioluminescent reaction. The time dependence of measured count rates of emitted photons has been analyzed by fitting with numerical solution of differential equations including the effect of the product-inhibitor and the deactivation of the luciferase. Through the analysis, we have successfully extracted kinetic constants such as, reaction rate, number of active luciferase molecules, etc. Ratio of active molecules to total luciferase molecules in immobilization was one order of magnitude lower than that in solution. The reaction rate of the bioluminescent process was also different from the one of free luciferase in solution.

  11. Role of immobilization of irradiated rats in the protective effect of bone marrow shielding

    NASA Technical Reports Server (NTRS)

    Gronskaya, N. F.; Strelin, G. S.

    1982-01-01

    Rats were exposed to X-radiation to study the influence of immobilization and shielding of part of bone marrow during exposure on survival. It is concluded that (1) the beneficial effect of the stress factor (created by the immobilization of rats during exposure) can aggregate with the effect of bone marrow shielding and, under certain conditions, imitate the latter; and (2) the probability of the protective effect of immobilization should be taken into account when assessing the influence of bone marrow shielding.

  12. Effects of immobilization on articular cartilage: Autohistoradiographic findings with S35

    NASA Technical Reports Server (NTRS)

    Digiovanni, C.; Desantis, E.

    1980-01-01

    The effect of immobilization on the articular cartilage of rabbits was studied by light microscope. The knee joint of each rabbit was immobilized in a plaster in a position midway between flexion and extension for a 10 to 120 days period. Degenerative changes in the articular cartilage of increasing severity were observed. The fixation of the labeled SO4 by cartilage cells was decreased in advanced immobilization.

  13. Graphene oxide immobilized enzymes show high thermal and solvent stability

    NASA Astrophysics Data System (ADS)

    Hermanová, Soňa; Zarevúcká, Marie; Bouša, Daniel; Pumera, Martin; Sofer, Zdeněk

    2015-03-01

    The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed lipase achieved over 100% of the initial activity in a series of organic solvents. These findings, showing enhanced thermal stability and solvent tolerance of graphene oxide immobilized enzyme, will have a profound impact on practical industrial scale uses of enzymes for the conversion of lipids into fuels.The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed

  14. Radiation immobilization of catalase and its application

    NASA Astrophysics Data System (ADS)

    Guanghui, Wang; Hongfei, Ha; Xia, Wang; Jilan, Wu

    Catalase was immobilized by chemical method on porous polyacrylamide particles which produced through radiation polymerization of acrylamide monomer at low temperature (-78°C). Activity of immobilized catalase was enhanced distinctly by joining a chemical "arm" to the support. The method of recovery of catalase activity on immobilized polymer was found by soaking it in certain buffer. The treatment of H 2O 2 both in aqueous solution and alcoholic solution by using the immobilized catalase was performed.

  15. Preparation, characterization, and luminescence of (SBA-15) immobilized pepsin

    NASA Astrophysics Data System (ADS)

    Zhai, Qing-Zhou; Sun, Si-Jia

    2014-12-01

    SBA-15 mesoporous silica was synthesized by hydrothermal method and its surface was methylated by treatment with methyltrimethoxysilane. Pepsin was immobilized on the obtained materials giving host-guest composite materials (SBA-15)-pepsin and (methylated SBA-15)-pepsin. The optimum conditions for preparation of these materials were established. Methylated SBA-15 (M-SBA-15) has improved immobilization efficiency of enzyme compared to initial SBA-15 silica. It was shown that with the gradual increase of NaCl solution ionic strength the immobilized amount of enzyme was reduced. Powder X-ray diffraction and Fourier transform infrared spectroscopy showed that the host frameworks in the prepared host-guest composite materials are intact and the ordered structure was retained. Scanning electron microscopic studies revealed fibrous morphologic characteristics of the SBA-15 and the immobilized pepsin composite materials. The average particle diameter of (SBA-15)-pepsin composite was 338 ± 10 and 343 ± 10 nm for (M-SBA-15)-pepsin. The low temperature N2 adsorption-desorption study at 77 K showed that the pore sizes and specific surface areas of the host-guest composite materials were smaller than those before the introduction of the enzyme, suggesting that the immobilized enzyme occupied a definite position in the host material pore channels. The UV-vis solid diffuse reflectance and luminescence studies showed that the enzyme was successfully immobilized on to the host material and that after the immobilization of enzyme on SBA-15 the conformation of pepsin macromolecule has not been changed.

  16. Immobilization of type-I collagen and basic fibroblast growth factor (bFGF) onto poly (HEMA-co-MMA) hydrogel surface and its cytotoxicity study.

    PubMed

    Yan, Tuo; Sun, Rong; Li, Chun; Tan, Baihua; Mao, Xuan; Ao, Ningjian

    2010-08-01

    Type-I collagen and bFGF were immobilized onto the surface of poly (HEMA-co-MMA) hydrogel by grafting and coating methods to improve its cytotoxicity. The multi-layered structure of the biocompatible layer was confirmed by FTIR, AFM and static water contact angles. The layers were stable in body-like environment (pH 7.4). Human skin fibroblast cells (HSFC) were seeded onto Col/bFGF-poly (HEMA-co-MMA), Col-poly (HEMA-co-MMA) and poly (HEMA-co-MMA) films for 1, 3 and 5 day. MTT assay was performed to evaluate the extraction toxicity of the materials. Results showed that the cell attachment, proliferation and differentiation on Col/bFGF-poly (HEMA-co-MMA) film were higher than those of the control group, which indicated the improvement of cell-material interaction. The extraction toxicity of the modified materials was also lower than that of the unmodified group. The protein and bFGF immobilized poly (HEMA-co-MMA) hydrogel might hold great promise to be a biocompatible material.

  17. The application of immobilized biocatalyzers to intensify the ethanol fermentation of lactose.

    PubMed

    Lewandowska, M; Bednarski, W; Adamczak, M; Narwojsz, D

    2003-01-01

    Ethanol fermentation of lactose mash by biocatalyzers immobilized in sodium alginate was studied in order to improve the process productivity and economy. The fermentation effectiveness of S.cerevisiae co-immobilized with a p-galactosidase and the directly lactose- fermenting immobilized yeast: K. fragilis and C. pseudotropicalis were compared The application of the immobilized K. fragilis produced desirable results and even after its 9th (18 days) fermentation, the immobilized yeast provided the stable high fermentation level (on average about 6 ralvol of ethano/) while maintaining its activity. Such lactose-mash fermentation was greater than in conventional method (by free cells). In addition, the application of s. cerevisiae co-immobilized with p-galactosidase produced somewhat greater ferm levels than the conventional method, however, the system stability deteriorated after 6 days of fermentation.

  18. Evaluation of immobilized enzymes for industrial applications.

    PubMed

    Liese, Andreas; Hilterhaus, Lutz

    2013-08-07

    In contrast to the application of soluble enzymes in industry, immobilized enzymes often offer advantages in view of stability, volume specific biocatalyst loading, recyclability as well as simplified downstream processing. In this tutorial review the focus is set on the evaluation of immobilized enzymes in respect to mass transport limitations, immobilization yield and stability, to enable industrial applications.

  19. Immobilized yeast for alcohol production

    SciTech Connect

    Not Available

    1982-02-03

    Construction of a pilot alcohol plant has been completed in Japan to test a new idea in fermentation that could cut the time required from three or four days to several hours. According to developers, the key is an unidentified radiation-cured polymer that is used to immobilize yeast, permitting the process to run continuously.

  20. Enzyme immobilization and biocatalysis of polysiloxanes

    NASA Astrophysics Data System (ADS)

    Poojari, Yadagiri

    Lipases have been proven to be versatile and efficient biocatalysts which can be used in a broad variety of esterification, transesterification, and ester hydrolysis reactions. Due to the high chemo-, regio-, and stereo-selectivity and the mild conditions of lipase-catalyzed reactions, the vast potential of these biocatalysts for use in industrial applications has been increasingly recognized. Polysiloxanes (silicones) are well known for their unique physico-chemical properties and can be prepared in the form of fluids, elastomers, gels and resins for a wide variety of applications. However, the enzymatic synthesis of silicone polyesters and copolymers is largely unexplored. In the present investigations, an immobilized Candida antarctica lipase B (CALB) on macroporous acrylic resin beads (Novozym-435 RTM) has been successfully employed as a catalyst to synthesize silicone polyesters and copolymers under mild reaction conditions. The silicone aliphatic polyesters and the poly(dimethylsiloxane)--poly(ethylene glycol) (PDMS-PEG) copolymers were synthesized in the bulk (without using a solvent), while the silicone aromatic polyesters, the silicone aromatic polyamides and the poly(epsilon-caprolactone)--poly(dimethylsiloxane)--poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers were synthesized in toluene. The synthesized silicone polyesters and copolymers were characterized by Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). This dissertation also describes a methodology for physical immobilization of the enzyme pepsin from Porcine stomach mucosa in silicone elastomers utilizing condensation-cure room temperature vulcanization (RTV) of silanol-terminated poly(dimethylsiloxane) (PDMS). The activity and the stability of free pepsin and pepsin immobilized in silicone elastomers were studied with respect to p

  1. DNA-directed immobilization of horseradish peroxidase onto porous SiO2 optical transducers

    NASA Astrophysics Data System (ADS)

    Shtenberg, Giorgi; Massad-Ivanir, Naama; Engin, Sinem; Sharon, Michal; Fruk, Ljiljana; Segal, Ester

    2012-08-01

    Multifunctional porous Si nanostructure is designed to optically monitor enzymatic activity of horseradish peroxidase. First, an oxidized PSi optical nanostructure, a Fabry-Pérot thin film, is synthesized and is used as the optical transducer element. Immobilization of the enzyme onto the nanostructure is performed through DNA-directed immobilization. Preliminary studies demonstrate high enzymatic activity levels of the immobilized horseradish peroxidase, while maintaining its specificity. The catalytic activity of the enzymes immobilized within the porous nanostructure is monitored in real time by reflective interferometric Fourier transform spectroscopy. We show that we can easily regenerate the surface for consecutive biosensing analysis by mild dehybridization conditions.

  2. Mineral induction by immobilized phosphoproteins

    NASA Technical Reports Server (NTRS)

    Saito, T.; Arsenault, A. L.; Yamauchi, M.; Kuboki, Y.; Crenshaw, M. A.

    1997-01-01

    Dentin phosphoproteins are thought to have a primary role in the deposition of mineral on the collagen of dentin. In this study we determined the type of binding between collagen and phosphoproteins necessary for mineral formation onto collagen fibrils and whether the phosphate esters are required. Bovine dentin phosphophoryn or phosvitin from egg yolk were immobilized on reconstituted skin type I collagen fibrils by adsorption or by covalent cross-linking. In some samples the ester phosphate was removed from the covalently cross-linked phosphoproteins by treatment with acid phosphatase. All samples were incubated at 37 degrees C in metastable solutions that do not spontaneously precipitate. Reconstituted collagen fibrils alone did not induce mineral formation. The phosphoproteins adsorbed to the collagen fibrils desorbed when the mineralization medium was added, and mineral was not induced. The mineral induced by the cross-linked phosphoproteins was apatite, and the crystals were confined to the surface of the collagen fibrils. With decreasing medium saturation the time required for mineral induction increased. The interfacial tensions calculated for apatite formation by either phosphoprotein cross-linked to collagen were about the same as that for phosphatidic acid liposomes and hydroxyapatite. This similarity in values indicates that the nucleation potential of these highly phosphorylated surfaces is about the same. It is concluded that phosphoproteins must be irreversibly bound to collagen fibrils for the mineralization of the collagen network in solutions that do not spontaneously precipitate. The phosphate esters of phosphoproteins are required for mineral induction, and the carboxylate groups are not sufficient.

  3. Recent developments and applications of immobilized laccase.

    PubMed

    Fernández-Fernández, María; Sanromán, M Ángeles; Moldes, Diego

    2013-12-01

    Laccase is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization. The immobilization of enzymes offers several improvements for enzyme applications because the storage and operational stabilities are frequently enhanced. Moreover, the reusability of immobilized enzymes represents a great advantage compared with free enzymes. In this work, we discuss the different methodologies of enzyme immobilization that have been reported for laccases, such as adsorption, entrapment, encapsulation, covalent binding and self-immobilization. The applications of laccase immobilized by the aforementioned methodologies are presented, paying special attention to recent approaches regarding environmental applications and electrobiochemistry.

  4. Degradation of Carbazole by Microbial Cells Immobilized in Magnetic Gellan Gum Gel Beads▿

    PubMed Central

    Wang, Xia; Gai, Zhonghui; Yu, Bo; Feng, Jinhui; Xu, Changyong; Yuan, Yong; Lin, Zhixin; Xu, Ping

    2007-01-01

    Polycyclic aromatic heterocycles, such as carbazole, are environmental contaminants suspected of posing human health risks. In this study, we investigated the degradation of carbazole by immobilized Sphingomonas sp. strain XLDN2-5 cells. Four kinds of polymers were evaluated as immobilization supports for Sphingomonas sp. strain XLDN2-5. After comparison with agar, alginate, and κ-carrageenan, gellan gum was selected as the optimal immobilization support. Furthermore, Fe3O4 nanoparticles were prepared by a coprecipitation method, and the average particle size was about 20 nm with 49.65-electromagnetic-unit (emu) g−1 saturation magnetization. When the mixture of gellan gel and the Fe3O4 nanoparticles served as an immobilization support, the magnetically immobilized cells were prepared by an ionotropic method. The biodegradation experiments were carried out by employing free cells, nonmagnetically immobilized cells, and magnetically immobilized cells in aqueous phase. The results showed that the magnetically immobilized cells presented higher carbazole biodegradation activity than nonmagnetically immobilized cells and free cells. The highest biodegradation activity was obtained when the concentration of Fe3O4 nanoparticles was 9 mg ml−1 and the saturation magnetization of magnetically immobilized cells was 11.08 emu g−1. Additionally, the recycling experiments demonstrated that the degradation activity of magnetically immobilized cells increased gradually during the eight recycles. These results support developing efficient biocatalysts using magnetically immobilized cells and provide a promising technique for improving biocatalysts used in the biodegradation of not only carbazole, but also other hazardous organic compounds. PMID:17827304

  5. Metal immobilization and soil amendment efficiency at a contaminated sediment landfill site: a field study focusing on plants, springtails, and bacteria.

    PubMed

    Bert, Valérie; Lors, Christine; Ponge, Jean-François; Caron, Lucie; Biaz, Asmaa; Dazy, Marc; Masfaraud, Jean-François

    2012-10-01

    Metal immobilization may contribute to the environmental management strategy of dredged sediment landfill sites contaminated by metals. In a field experiment, amendment effects and efficiency were investigated, focusing on plants, springtails and bacteria colonisation, metal extractability and sediment ecotoxicity. Conversely to hydroxylapatite (HA, 3% DW), the addition of Thomas Basic Slag (TBS, 5% DW) to a 5-yr deposited sediment contaminated with Zn, Cd, Cu, Pb and As resulted in a decrease in the 0.01 M Ca(NO(3))(2)-extractable concentrations of Cd and Zn. Shoot Cd and Zn concentration in Calamagrostis epigejos, the dominant plant species, also decreased in the presence of TBS. The addition of TBS and HA reduced sediment ecotoxicity and improved the growth of the total bacterial population. Hydroxylapatite improved plant species richness and diversity and decreased antioxidant enzymes in C. Epigejos and Urtica dïoica. Collembolan communities did not differ in abundance and diversity between the different treatments.

  6. A High-Resolution Magic Angle Spinning NMR Study of the Enantiodiscrimination of 3,4-Methylenedioxymethamphetamine (MDMA) by an Immobilized Polysaccharide-Based Chiral Phase

    PubMed Central

    Paixão, Márcio W.; Lourenço, Tiago C.

    2016-01-01

    This paper reports the investigation of the chiral interaction between 3,4-methylenedioxy-methamphetamine (MDMA) enantiomers and an immobilized polysaccharide-based chiral phase. For that, suspended-state high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (1H HR-MAS NMR) was used. 1H HR-MAS longitudinal relaxation time and Saturation Transfer Difference (STD NMR) titration experiments were carried out yielding information at the molecular level of the transient diastereoisomeric complexes of MDMA enantiomers and the chiral stationary phase. The interaction of the enantiomers takes place through the aromatic moiety of MDMA and the aromatic group of the chiral selector by π-π stacking for both enantiomers; however, a stronger interaction was observed for the (R)-enantiomer, which is the second one to elute at the chromatographic conditions. PMID:27668862

  7. Algal polysaccharides as matrices for the immobilization of urease in lipid ultrathin films studied with tensiometry and vibrational spectroscopy: Physical-chemical properties and implications in the enzyme activity.

    PubMed

    de Brito, Audrey Kalinouski; Nordi, Cristina S F; Caseli, Luciano

    2015-11-01

    Currently, many biological substances extracted from algae have received special attention because of their intrinsic characteristics, which can be applied to different areas of biotechnology. Therefore, in the current study, exopolysaccharides (EPS) from the microalgae Cryptomonas tetrapirenoidosa were employed as an aqueous subphase of a monolayer formed by the lipid dioctadecyldimethylammonium bromide (DODAB). The primary objective of this approach was to evaluate whether EPS could serve as a matrix for the immobilization of the enzyme urease to produce biosensors for urea. After DODAB was spread on the EPS solutions, urease was injected into the aqueous subphase, and the surface was submitted to compression using lateral barriers. The monolayers were subsequently characterized by surface pressure-area isotherms and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). The results indicated that EPS enhanced the adsorption of the enzyme on the lipid monolayer. The mixed films were later transferred to solid supports using the Langmuir-Blodgett (LB) technique and were characterized by transfer ratio, PM-IRRAS, quartz crystal microbalance, and atomic force microscopy. The immobilization of the enzyme on solid supports was fundamental for providing an ideal geometrical accommodation of urease because the interaction of EPS with urease in solution causes a decrease of the relative activity of urease. Therefore, these LB films are promising for the fabrication of future urea biosensors, the architecture of which can be manipulated and enhanced at the molecular level.

  8. Evaluation of an organo-layered double hydroxide and two organic residues as amendments to immobilize metalaxyl enantiomers in soils: A comparative study.

    PubMed

    López-Cabeza, Rocío; Cornejo, Juan; Celis, Rafael

    2016-10-01

    Many pollutants released into the environment as a result of human activities are chiral. Pollution control strategies generally consider chiral compounds as if they were achiral and rarely consider enantiomers separately. We compared the performance of three different materials, an organically-modified anionic clay (HT-ELA) and two organic agro-food residues (ALP and ALPc), as amendments to immobilize the chiral fungicide metalaxyl in two soils with different textures, addressing the effects of the amendments on the sorption, persistence, and leaching of each of the two enantiomers of metalaxyl (R-metalaxyl and S-metalaxyl) separately. The effects of the amendments were both soil- and amendment-dependent, as well as enantiomer-selective. The organo-clay (HT-ELA) was much more efficient in increasing the sorption capacity of the soils for the two enantiomers of metalaxyl than the agro-food residues (ALP and ALPc), even when applied at a reduced application rate. The enhanced sorption in HT-ELA-amended soils reduced the bioavailability of metalaxyl enantiomers and their leaching in the soils, mitigating the particularly high leaching potential of the more persistent S enantiomer. The immobilizing capacity of the agro-food residues was more variable, mainly because their addition did not greatly ameliorate the sorption capacity of the soils and had variable effects on the enantiomers degradation rates. HT-ELA showed potential to reduce the bioavailability and mobility of metalaxyl enantiomers in soil and to mitigate the contamination problems particularly associated with the higher leaching potential of the more persistent enantiomer.

  9. Effects of acoustic wave resonance oscillation on immobilized enzyme

    NASA Astrophysics Data System (ADS)

    Nishiyama, Hiroshi; Watanabe, Tomoya; Inoue, Yasunobu

    2014-03-01

    In aiming at developing a new method to artificially activate enzyme catalysts immobilized on surface, the effects of resonance oscillation of bulk acoustic waves were studied. Glucose oxidase (GOD) was immobilized by a covalent coupling method on a ferroelectric lead zirconate titanate (PZT) device that was able to generate thickness-extensional resonance oscillation (TERO). Glucose oxidation by the GOD enzyme was studied in a microreactor. The generation of TERO immediately increased the catalytic activity of immobilized GOD by a factor of 2-3. With turn-off of TERO, no significant activity decrease occurred, and 80-90% of the enhanced activity was maintained while the reaction proceeded. The almost complete reversion of the activity to the original low level before TERO generation was observed when the immobilized GOD was exposed to a glucose substrate-free solution. These results indicated that the presence of glucose substrate was essential for TERO-induced GOD activation and preservation of the increased activity level. The influences of reaction temperature, glucose concentration, pH, and rf electric power on the TERO activation showed that TERO strengthened the interactions of the immobilized enzyme with glucose substrate and hence promoted the formation of an activation complex.

  10. Immobilization of diastase α-amylase on nano zinc oxide.

    PubMed

    Antony, Navya; Balachandran, S; Mohanan, P V

    2016-11-15

    Diastase α-amylase extracted from malt, catalyses break down of starch into maltose. It is commonly used in food and fermentation industry. In the present study nano zinc oxide is used as support for this starch hydrolyzing enzyme. IR study revealed that the enzyme got adsorbed via electrostatic interaction with the functional groups on the support. The immobilized enzyme possessed a better heat-resistance than free enzyme. The kinetic parameters were determined using Lineweaver-Burk plot. The immobilized enzyme showed higher Km 2.08mg/ml than the free enzyme whose Km is 0.45±.05mg/ml. The Vmax of immobilized enzyme was about 2.92±.02mg/ml/min and that of free enzyme was 7.14±.02mg/ml/min, showing decrease in activity after immobilization. The immobilized enzyme showed 70% activity after 30days of storage while free enzyme lost its activity within 7days. About 80% of enzyme retained activity after 4 cycles of reuse.

  11. Biodiesel production with immobilized lipase: A review.

    PubMed

    Tan, Tianwei; Lu, Jike; Nie, Kaili; Deng, Li; Wang, Fang

    2010-01-01

    Fatty acid alkyl esters, also called biodiesel, are environmentally friendly and show great potential as an alternative liquid fuel. Biodiesel is produced by transesterification of oils or fats with chemical catalysts or lipase. Immobilized lipase as the biocatalyst draws high attention because that process is "greener". This article reviews the current status of biodiesel production with immobilized lipase, including various lipases, immobilization methods, various feedstocks, lipase inactivation caused by short chain alcohols and large scale industrialization. Adsorption is still the most widely employed method for lipase immobilization. There are two kinds of lipase used most frequently especially for large scale industrialization. One is Candida antartica lipase immobilized on acrylic resin, and the other is Candida sp. 99-125 lipase immobilized on inexpensive textile membranes. However, to further reduce the cost of biodiesel production, new immobilization techniques with higher activity and stability still need to be explored.

  12. Effect of membranes with various hydrophobic/hydrophilic properties on lipase immobilized activity and stability.

    PubMed

    Chen, Guan-Jie; Kuo, Chia-Hung; Chen, Chih-I; Yu, Chung-Cheng; Shieh, Chwen-Jen; Liu, Yung-Chuan

    2012-02-01

    In this study, three membranes: regenerated cellulose (RC), glass fiber (GF) and polyvinylidene fluoride (PVDF), were grafted with 1,4-diaminobutane (DA) and activated with glutaraldehyde (GA) for lipase covalent immobilization. The efficiencies of lipases immobilized on these membranes with different hydrophobic/hydrophilic properties were compared. The lipase immobilized on hydrophobic PVDF-DA-GA membrane exhibited more than an 11-fold increase in activity compared to its immobilization on a hydrophilic RC-DA-GA membrane. The relationship between surface hydrophobicity and immobilized efficiencies was investigated using hydrophobic/hydrophilic GF membranes which were prepared by grafting a different ratio of n-butylamine/1,4-diaminobutane (BA/DA). The immobilized lipase activity on the GF membrane increased with the increased BA/DA ratio. This means that lipase activity was exhibited more on the hydrophobic surface. Moreover, the modified PVDF-DA membrane was grafted with GA, epichlorohydrin (EPI) and cyanuric chloride (CC), respectively. The lipase immobilized on the PVDF-DA-EPI membrane displayed the highest specific activity compared to other membranes. This immobilized lipase exhibited more significant stability on pH, thermal, reuse, and storage than did the free enzyme. The results exhibited that the EPI modified PVDF is a promising support for lipase immobilization.

  13. Protein immobilization onto various surfaces using a polymer-bound isocyanate

    NASA Astrophysics Data System (ADS)

    Kang, Hyun-Jin; Cha, Eun Ji; Park, Hee-Deung

    2015-01-01

    Silane coupling agents have been widely used for immobilizing proteins onto inorganic surfaces. However, the immobilization method using silane coupling agents requires several treatment steps, and its application is limited to only surfaces containing hydroxyl groups. The aim of this study was to develop a novel method to overcome the limitations of the silane-based immobilization method using a polymer-bound isocyanate. Initially, polymer-bound isocyanate was dissolved in organic solvent and then was used to dip-coat inorganic surfaces. Proteins were then immobilized onto the dip-coated surfaces by the formation of urea bonds between the isocyanate groups of the polymer and the amine groups of the protein. The reaction was verified by FT-IR in which NCO stretching peaks disappeared, and CO and NH stretching peaks appeared after immobilization. The immobilization efficiency of the newly developed method was insensitive to reaction temperatures (4-50 °C), but the efficiency increased with reaction time and reached a maximum after 4 h. Furthermore, the method showed comparable immobilization efficiency to the silane-based immobilization method and was applicable to surfaces that cannot form hydroxyl groups. Taken together, the newly developed method provides a simple and efficient platform for immobilizing proteins onto surfaces.

  14. Comparative evaluation of pumice stone as an alternative immobilization material for 1,3-propanediol production from waste glycerol by immobilized Klebsiella pneumoniae.

    PubMed

    Gonen, Cagdas; Gungormusler, Mine; Azbar, Nuri

    2012-12-01

    In this study, pumice stone (PS), which is a vastly available material in Turkey, was evaluated as an alternative immobilization material in comparison to other commercially available immobilization materials such as glass beads and polyurethane foam. All immobilized bioreactors resulted in much better 1,3-propanediol production from waste glycerol in comparison to the suspended cell culture bioreactor. It was also demonstrated that the locally available PS material is as good as the commercially available immobilization material. The maximum volumetric productivity (8.5 g L(-1) h(-1)) was obtained by the PS material, which is 220 % higher than the suspended cell system. Furthermore, the immobilized bioreactor system was much more robust against cell washout even at very low hydraulic retention time values.

  15. Activity stabilization of Aspergillus niger and Escherichia coli phytases immobilized on allophanic synthetic compounds and montmorillonite nanoclays.

    PubMed

    Menezes-Blackburn, Daniel; Jorquera, Milko; Gianfreda, Liliana; Rao, Maria; Greiner, Ralf; Garrido, Elizabeth; de la Luz Mora, María

    2011-10-01

    The aim of this work was to study the stabilization of the activity of two commercial microbial phytases (Aspergillus niger and Escherichia coli) after immobilization on nanoclays and to establish optimal conditions for their immobilization. Synthetic allophane, synthetic iron-coated allophanes and natural montmorillonite were chosen as solid supports for phytase immobilization. Phytase immobilization patterns at different pH values were strongly dependent on both enzyme and support characteristics. After immobilization, the residual activity of both phytases was higher under acidic conditions. Immobilization of phytases increased their thermal stability and improved resistance to proteolysis, particularly on iron-coated allophane (6% iron oxide), which showed activation energy (E(a)) and activation enthalpy (ΔH(#)) similar to free enzymes. Montmorillonite as well as allophanic synthetic compounds resulted in a good support for immobilization of E. coli phytase, but caused a severe reduction of A. niger phytase activity.

  16. Immobilization of glucosyltransferase from Erwinia sp. using two different techniques.

    PubMed

    Contesini, Fabiano Jares; Ibarguren, Carolina; Grosso, Carlos Raimundo Ferreira; Carvalho, Patrícia de Oliveira; Sato, Hélia Harumi

    2012-04-15

    Two different techniques of glucosyltransferase immobilization were studied for the conversion of sucrose into isomaltulose. The optimum conditions for immobilization of Erwinia sp. glucosyltransferase onto Celite 545, determined using response surface methodology, was pH 4.0 and 170 U of glucosyltransferase/g of Celite 545. Using this conditions more than 60% conversion of sucrose into isomaltulose can be obtained. The immobilization of glucosyltransferase was also studied by its entrapment in microcapsules of low-methoxyl pectin and fat (butter and oleic acid). The non-lyophilized microcapsules of pectin, containing the enzyme and fat, showed higher glucosyltransferase activity, compared with lyophilized microcapsules containing enzyme plus fat, and also lyophilized microcapsules containing enzyme without fat addition. The non-lyophilized microcapsules of pectin containing the glucosyltransferase and fat, converted 30% of sucrose into isomaltulose in the first batch. However the conversion decreased to 5% at the 10th batch, indicating inactivation of the enzyme.

  17. Immobilization of Yarrowia lipolytica for aroma production from castor oil.

    PubMed

    Braga, Adelaide; Belo, Isabel

    2013-04-01

    The main aim of this study was to compare different materials for Y. lipolytica immobilization that could be used in the production of γ-decalactone (a peach-like aroma) in order to prevent the toxic effect both of the substrate and the aroma upon the cells. Therefore, cells adsorption onto pieces of methyl polymethacrylate and of DupUM(®) was studied and further used in the biotransformation of castor oil into γ-decalactone. The highest aroma concentration was obtained with immobilized cells in DupUM(®), where reconsumption of the aroma by the cells was prevented, contrarily to what happens with free cells. This is a very promising result for γ-decalactone production, with potential to be used at an industrial level since the use of immobilized cells system will facilitate the conversion of a batch process into a continuous mode keeping high cell density and allowing easier recovery of metabolic products.

  18. Surplus plutonium immobilization feed materials requirements and blending strategy

    SciTech Connect

    Ebbinghaus, B.; Edmunds, T.; Gray, L.; Riley, D.; Rising, T.L.

    1998-02-13

    The Excess Fissile Materials Disposition Program`s Record of Decision (ROD) published in January 1997 by DOE/MD describes three potential pathways for the disposition of excess fissile materials: burning as MOX fuel rods, and two can-in-canister immobilization candidates: glass and ceramics. In addition, the ROD introduced processing schedules for MD disposition program. Prior to the ROD, the only acceptance specification that AMD had for incoming materials was DOE- STD-3013. However, STD-3013 is a specification aimed at maintaining safety for long term storage (approximately 100 years) and was never intended to act as an acceptance specification. An effort has begun to examine all of the technical issues associated with the processing and transfer of materials from EM to MD. Since that time, several related initiatives have begun to deal with the many issues, including the EM Material Stewardship program, the latest EM-66 sponsored trade studies, and a new storage standard. A draft of feed material requirements for the ceramic Immobilization Facility that will be used for the disposition of surplus plutonium has been developed for discussion. It established impurity limits for feed materials to the immobilization process, identifies impurities in feed materials that may have an adverse effect on the immobilization process, and indicates how these materials can be further processed and blended at the Immobilization Facility to ensure manufacture of an acceptable product.

  19. In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts

    SciTech Connect

    Davis, Robert, J.

    2007-11-14

    Immobilized organometallic catalysts, in principle, can give high rates and selectivities like homogeneous catalysts with the ease of separation enjoyed by heterogeneous catalysts. However, the science of immobilized organometallics has not been developed because the field lies at the interface between the homogeneous and heterogeneous catalysis communities. By assembling an interdisciplinary research team that can probe all aspects of immobilized organometallic catalyst design, the entire reacting system can be considered, where the transition metal complex, the complex-support interface and the properties of the support can all be considered simultaneously from both experimental and theoretical points of view. Researchers at Georgia Tech and the University of Virginia are studying the fundamental principles that can be used to understand and design future classes of immobilized organometallic catalysts. In the framework of the overall collaborative project with Georgia Tech, our work focused on (a) the X-ray absorption spectroscopy of an immobilized Pd-SCS-O complex (b) the mode of metal leaching from supported Pd catalysts during Heck catalysis and (c) the mode of deactivation of Jacobsen’s Co-salen catalysts during the hydrolytic kinetic resolution of terminal epoxides. Catalysts containing supported Pd pincer complexes, functionalized supports containing mercapto and amine groups, and oligomeric Co-salen catalysts were synthesized at Georgia Tech and sent to the University of Virginia. Incorporation of Pd onto several different kinds of supports (silica, mercapto-functionalized silica, zeolite Y) was performed at the University of Virginia.

  20. [Immobilization of heavy metal Pb2+ with geopolymer].

    PubMed

    Jin, Man-tong; Jin, Zan-fang; Huang, Cai-ju

    2011-05-01

    A series of geopolymers were synthesized by mixing metakaolinite, water glass, sodium hydroxide and water, and the lead ion solidification experiments were performed with the geopolymer. Then, the immobilization efficiency was characterized by monitoring the leaching concentration and compressive strength of solidified products. Additionally, the structure and properties of the solidified products were studied by X-ray diffraction (XRD), scan electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of immobilization efficiency, microstructure and mineral structure, the difference between geopolymer and cement on the performance of immobilizing heavy metals was discussed. The results of lead ion immobilization experiments showed that over 99.7% of heavy metal was captured by the geopolymer as the doping concentration of lead ion was less than 3%. Meanwhile, the compressive strength of the solidified product ranged from 40 MPa to 50 MPa. Furthermore, by using the same Pb2+ concentration, the geopolymer showed higher compressive strength and lower leaching concentration compared to the cement. Because lead ion participated in constitution of structure of geopolymer, or Pb2+ was adsorbed by the aluminium ions on the geopolymeric skeleton and held in geopolymer. However, cement mainly solidified lead ion by physical encapsulation and adsorption mechanism. Therefore, both from the compressive strength and leaching concentration and from the microstructure characterization as well as the mechanism of the geopolymerization reaction, the geopolymer has more advantages in immobilizing Pb2+ than the cement.

  1. Immobilization of iodine in concrete

    DOEpatents

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  2. A facile and effective immobilization of glucose oxidase on tannic acid modified CoFe2O4 magnetic nanoparticles.

    PubMed

    Altun, Seher; Çakıroğlu, Bekir; Özacar, Münteha; Özacar, Mahmut

    2015-12-01

    This article presents a study of glucose oxidase (GOx) immobilization by employing tannic acid (TA) modified-CoFe2O4 (CFO) magnetic nanoparticles which demonstrates novel aspect for enzyme immobilization. By using the strong protein and tannic acid binding, GOx immobilization was carried out via physical adsorption in a simpler way compared with the other immobilization methods which require various chemicals and complicated procedures which is difficult, expensive, time-consuming, and destructive to the enzyme structure. CFO was synthesized by hydrothermal synthesis and modified with TA to immobilize GOx. The immobilized GOx demonstrated maximum catalytic activity at pH 6.5 and 45 °C. The samples were characterized by vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential, and fourier transform infrared spectroscopy (FTIR), all of which confirm the surface modification of CFO and GOx immobilization. Also, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were performed to demonstrate the surface morphology and chemical structure of samples. According to the Lineweaver-Burk plot, GOx possessed lower affinity to glucose after immobilization, and the Michelis-Menten constant (KM) of immobilized and free GOx were found to be 50.05 mM and 28.00 mM, respectively. The immobilized GOx showed excellent reusability, and even after 8 consecutive activity assay runs, the immobilized GOx maintained ca. 60% of its initial activity.

  3. Silica-Immobilized Enzyme Reactors

    DTIC Science & Technology

    2007-08-01

    relief from the symptoms of inflammation and pain Silica-IMERs 10 and is the mode of action of drugs such as aspirin and ibuprofen .[61] Serotonin...supports and using the enantiomeric selectivity of the enzyme to resolve racemic mixtures.[100] Immobilization onto supports with various pore sizes and...activity (~37%) and used as a packed- bed IMER to catalyze the racemic resolution of (S)-ketoprofen from its constituent enantiomers . The optically pure (S

  4. Immobilized Enzymes for Automated Analyses.

    DTIC Science & Technology

    1979-12-01

    by others. Reaction velocity was found to increase with temperature at a rate of about 5%/’C. Three distinct types of immobilization processes were...trifunctional silane ........... 10 2 Linearity of protein assay ............................. 14 3 Reaction rate for native and oxygenated enzyme solu...in a clinical chemistry analyzer enables catalysis of the analyzer reactions with retention of active enzyme by the system for subsequent reuse. When a

  5. Photo induced surface heparin immobilization.

    PubMed

    Nakayama, Y; Matsuda, T

    1993-01-01

    This paper describes a novel method providing durable layering of heparin immobilized hydrogels on fabricated devices. The preparation method is based on photochemistry of a dithiocarbamate group that is dissociated into a highly reactive radical pair upon ultraviolet (UV) irradiation. By taking advantage of characteristics of the photo generated radicals, hydrogel formation and its fixation onto a substrate surface were attained. The immobilization of heparin onto poly(ethylene terephtalate) was demonstrated. First, a mixed aqueous solution containing a photoreactive water soluble poly(N,N-dimethylacrylamide-covinylbenzyl N,N-diethyldithiocarbamate) and heparin was coated on the substrate. Subsequent UV irradiation resulted in the simultaneous formation of a heparin immobilized hydrogel and its chemical fixation onto the substrate. No delamination was found after vigorous washing with water. Significant inhibition of platelet adhesion and markedly prolonged blood coagulation times were observed, which are apparently derived from the surface hydrogel, and from released and chemically fixed surface heparin. Thus, it is expected that the photochemical method developed here provides potent antithrombogenicity to artificial organs.

  6. Industrial applications of immobilized cells

    SciTech Connect

    Linko, P.; Linko, Y.Y.

    1984-01-01

    Although the application of the natural attraction of many microorganisms to surfaces has been applied in vinegar production since the early 1980s, and has long been utilized in waste water purification, the development of microbial cell immobilization techniques for special applications dates back only to the early 1960s. The immobilization may involve whole cells, cell fragments, or lysed cells. Whole cells may retain their metabolic activity with their complex multienzyme systems and cofactor regeneration mechanisms intact, or they may be killed in the process with only a few desired enzymes remaining active in the final biocatalyst. Cells may also be coimmobilized with an enzyme to carry out special reactions. Although relatively few industrial scale applications exist today, some are of very large scale. Current applications vary from relatively small scale steroid conversions to amino acid production and high fructose syrup manufacture. A vast number of potential applications are already known, and one of the most interesting applications may be in continuous fermentation such as ethanol production by immobilized living microorganisms. 373 references.

  7. Covalent immobilization of ascorbate oxidase onto polycarbonate strip for L-ascorbic acid detection.

    PubMed

    Kannoujia, Dileep Kumar; Kumar, Saroj; Nahar, Pradip

    2012-10-01

    Herein, a simple and rapid method is described for detection of L-ascorbic acid by ascorbate oxidase immobilized onto polycarbonate strip pre-activated by 1-fluoro-2-nitro-4-azidobenzene in photochemical reaction. Covalent attachment of ascorbate oxidase was confirmed by XPS studies. The immobilized-ascorbate oxidase shows higher pH, thermal and storage stability in comparison to free enzyme.

  8. Anticoagulation and antiplatelet effects of semax under conditions of acute and chronic immobilization stress.

    PubMed

    Grigorjeva, M E; Lyapina, L A

    2010-07-01

    The effects of semax on anticoagulant, fibrinolytic, and platelet components of the anticoagulation system were studied on albino rats under conditions of acute and chronic immobilization stress. Semax exhibited a protective antistress effect after repeated intranasal administration under conditions of hypercoagulation developing in response to immobilization stress of different degree. The effect manifested in stimulation of the anticoagulation system.

  9. Characterization of phase evolution during lead immobilization by synthetic hydroxyapatite

    SciTech Connect

    Mavropoulos, Elena; Rocha, Nilce C.C.; Soares, Gloria A. . E-mail: Gloria@ufrj.br

    2004-09-15

    Immobilization of toxic metals by calcium phosphates is a promising technology for treating contaminated soil, water and wastes. A detailed study on the mechanisms of lead immobilization by hydroxyapatite has been carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). For this, synthetic hydroxyapatite powder were submitted to a sorption process through exposure to an aqueous solution containing 917 mg L{sup -1} of lead for times that varied from 3 min to 54 h. The results obtained reinforce the hypothesis that hydroxypyromorphite formation is the end of a kinetic process in which the hydroxyapatite crystals are continuously dissolved and recrystallized in order to form more stable structures with higher lead content. Consequently, the use of calcium phosphates to immobilize lead ions seems to be technically viable.

  10. Immobilization of photosynthetic reaction centers on metal surfaces

    SciTech Connect

    Cotton, T.M.; Chumanov, G.; Gual, D.

    1993-12-31

    Membrane-bound proteins are ideal candidates for immobilization on surfaces because of their distinct hydrophobic and hydrophilic regions. Their interaction with a particular surface should depend upon its hydrophilicity. Variation of the surface properties is expected to result in changes in the orientation of an absorbed protein. In this study, two methods for immobilization of reaction centers from Rhodobacter sphaeroids on metal surfaces have been compared, including self-assembly or spontaneous adsorption and Langmuir-Blodgett transfer of monolayers from an air/water interface. The effect of the immobilization procedure on the structure of the protein complex has been determined from photochemical activity and optical measurements. The experimental variables which are critical for maintaining the structure and function of the protein in the adsorbed state will be discussed.

  11. Purification, immobilization, and characterization of nattokinase on PHB nanoparticles.

    PubMed

    Deepak, Venkataraman; Pandian, Suresh babu Ram Kumar; Kalishwaralal, Kalimuthu; Gurunathan, Sangiliyandi

    2009-12-01

    In this study, nattokinase was purified from Bacillus subtilis using ion exchange chromatography and immobilized upon polyhydroxybutyrate (PHB) nanoparticles. A novel strain isolated from industrial dairy waste was found to synthesize polyhydroxyalkanoates (PHA) and the strain was identified as Brevibacterium casei SRKP2. PHA granules were extracted from 48 h culture and the FT-IR analysis characterized them as PHB, a natural biopolymer from B. casei. Nanoprecipitation by solvent displacement technique was used to synthesize PHB nanoparticles. PHB nanoparticles were characterized using transmission electron microscopy and particle size ranged from 100-125 nm. Immobilization of nattokinase upon PHB nanoparticles resulted in a 20% increase in the enzyme activity. Immobilization also contributed to the enhanced stability of the enzyme. Moreover, the activity was completely retained on storage at 4 degrees C for 25 days. The method has proven to be highly simple and can be implemented to other enzymes also.

  12. Immobilized enzymes in blood plasma exchangers via radiation grafting

    NASA Astrophysics Data System (ADS)

    Gombotz, Wayne; Hoffman, Allan; Schmer, Gottfried; Uenoyama, Satoshi

    The enzyme asparaginase was immobilized onto a porous hollow polypropylene (PP) fiber blood plasma exchange device for the treatment of acute lymphocytic leukemia. The devices were first radiation grafted with polymethacrylic acid (poly(MAAc)). This introduces carboxyl groups onto the surface of the fibers. Several variables were studied in the grafting reaction including the effects of solvent type and monomer concentration. The carboxyl groups were activated with N-hydroxy succinimide (NHS) using carbodiimide chemistry. Asparaginase was then covalently immobilized on the activated surfaces. Quantitative relationships were found relating the percent graft to the amount of immobilized enzyme which was active. The enzyme reactor was tested both in vitro and in vivo using a sheep as an animal model.

  13. Immobilization of silver nanoparticles on silica microspheres

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Kai; Chen, Chia-Yin; Han, Jin-Lin; Chen, Chii-Chang; Jiang, Meng-Dan; Hsu, Jen-Sung; Chan, Chia-Hua; Hsieh, Kuo-Huang

    2010-01-01

    The silver nanoparticles (Ag NPs) have been immobilized onto silica microspheres through the adsorption and subsequent reduction of Ag+ ions on the surfaces of the silica microspheres. The neat silica microspheres that acted as the core materials were prepared through sol-gel processing; their surfaces were then functionalized using 3-mercaptopropyltrimethoxysilane (MPTMS). The major aims of this study were to immobilize differently sized Ag particles onto the silica microspheres and to understand the mechanism of formation of the Ag nano-coatings through the self-assembly/adsorption behavior of Ag NPs/Ag+ ions on the silica spheres. The obtained Ag NP/silica microsphere conglomerates were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). Their electromagnetic wave shielding effectiveness were also tested and studied. The average particle size of the obtained Ag NPs on the silica microsphere was found that could be controllable (from 2.9 to 51.5 nm) by adjusting the ratio of MPTMS/TEOS and the amount of AgNO3.

  14. Immobilization of Penaeus merguiensis alkaline phosphatase on gold nanorods for heavy metal detection.

    PubMed

    Homaei, Ahmad

    2017-02-01

    Biotechnology of enzyme has gained popularity due to the growing need for novel environmental technologies and the development of innovative mass-production. The work describes the original application of biosensors based on Penaeus merguiensis alkaline phosphatase (PM ALP) immobilized on gold nanorods (GNRs) to heavy metal determination. Penaeus merguiensis alkaline phosphatase (PM ALP) was immobilized on gold nanorods (GNRs) by ionic exchange and hydrophobic interactions. The optimum pH and temperature for maximum enzyme activity for the immobilized PM ALP are identified to be 11.0 and 60°C, respectively, for the hydrolysis of para-Nitrophenylphosphate (p-NPP). The kinetic studies confirm the Michaelis-Menten behavior and suggests overall slightly decrease in the performance of the immobilized enzyme with reference to the free enzyme. Km and Vmax values were 0.32µm and 54µm. min(-1) for free and 0.39µm and 48µmmin(-1) for immobilized enzymes, respectively. Similarly, the thermal stability, storage stability and stability at extreme pH of the enzyme is found to increase after the immobilization. The inhibitory effect heavy metal ions was studied on free and immobilized PM ALP. The bi-enzymatic biosensor were tested to study the influence of heavy metal ions and pesticides on the corresponding enzyme. The obtained high stability and lower decrease in catalytic efficiency suggested the great potential and feasibility of immobilized PM ALP nanobiocatalyst in efficient and apply the biosensor in total toxic metal content determination.

  15. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres

    PubMed Central

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A.; El-Toni, Ahmed M.; Almaary, Khalid S.; El-Tayeb, Mohamed A.; Elbadawi, Yahya B.; Antranikian, Garabed

    2016-01-01

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS–NH2 nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher Vmax, kcat and kcat/Km, than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media. PMID:26840303

  16. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres.

    PubMed

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A; El-Toni, Ahmed M; Almaary, Khalid S; El-Tayeb, Mohamed A; Elbadawi, Yahya B; Antranikian, Garabed

    2016-01-29

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS-NH₂ nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher V(max), k(cat) and k(cat)/K(m), than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media.

  17. Utilization of immobilized urease for waste water treatment

    NASA Technical Reports Server (NTRS)

    Husted, R. R.

    1974-01-01

    The feasibility of using immobilized urease for urea removal from waste water for space system applications is considered, specifically the elimination of the urea toxicity problem in a 30-day Orbiting Frog Otolith (OFO) flight experiment. Because urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, control of their concentrations within nontoxic limits was also determined. The results of this study led to the use of free urease in lieu of the immobilized urease for controlling urea concentrations. An ion exchange resin was used which reduced the NH3 level by 94% while reducing the sodium ion concentration only 10%.

  18. Analysis of alternatives for immobilized low activity waste disposal

    SciTech Connect

    Burbank, D.A.

    1997-10-28

    This report presents a study of alternative disposal system architectures and implementation strategies to provide onsite near-surface disposal capacity to receive the immobilized low-activity waste produced by the private vendors. The analysis shows that a flexible unit strategy that provides a suite of design solutions tailored to the characteristics of the immobilized low-activity waste will provide a disposal system that best meets the program goals of reducing the environmental, health, and safety impacts; meeting the schedule milestones; and minimizing the life-cycle cost of the program.

  19. Drop drying on surfaces determines chemical reactivity - the specific case of immobilization of oligonucleotides on microarrays

    PubMed Central

    2013-01-01

    Background Drop drying is a key factor in a wide range of technical applications, including spotted microarrays. The applied nL liquid volume provides specific reaction conditions for the immobilization of probe molecules to a chemically modified surface. Results We investigated the influence of nL and μL liquid drop volumes on the process of probe immobilization and compare the results obtained to the situation in liquid solution. In our data, we observe a strong relationship between drop drying effects on immobilization and surface chemistry. In this work, we present results on the immobilization of dye labeled 20mer oligonucleotides with and without an activating 5′-aminoheptyl linker onto a 2D epoxysilane and a 3D NHS activated hydrogel surface. Conclusions Our experiments identified two basic processes determining immobilization. First, the rate of drop drying that depends on the drop volume and the ambient relative humidity. Oligonucleotides in a dried spot react unspecifically with the surface and long reaction times are needed. 3D hydrogel surfaces allow for immobilization in a liquid environment under diffusive conditions. Here, oligonucleotide immobilization is much faster and a specific reaction with the reactive linker group is observed. Second, the effect of increasing probe concentration as a result of drop drying. On a 3D hydrogel, the increasing concentration of probe molecules in nL spotting volumes accelerates immobilization dramatically. In case of μL volumes, immobilization depends on whether the drop is allowed to dry completely. At non-drying conditions, very limited immobilization is observed due to the low oligonucleotide concentration used in microarray spotting solutions. The results of our study provide a general guideline for microarray assay development. They allow for the initial definition and further optimization of reaction conditions for the immobilization of oligonucleotides and other probe molecule classes to different

  20. Immobilization of the urease on eggshell membrane and its application in biosensor.

    PubMed

    D'Souza, S F; Kumar, Jitendra; Jha, Sandeep Kumar; Kubal, B S

    2013-03-01

    Eggshell membrane is a natural material, essentially made up of protein fibers having flexibility in the aqueous solution and possessing gas and water permeability. It is used as a biomembrane for immobilization of urease for the development of a potentiometric urea biosensor. Eggshell membrane was treated with polyethyleneimine (PEI) to impart polycation characteristics. Urease was immobilized on the PEI treated eggshell membrane through adsorption. SEM study was carried out to observe the changes in surface morphology after immobilization. FTIR study of membrane was carried out to observe the changes in IR spectra after immobilization of enzyme. Immobilized membrane was associated with ammonium ion selective electrode. Biosensor exhibited sigmoidal responses for the urea concentration range from 0.5 to 10mM. The response time of the biosensor was 120 s. A single membrane was reused for 270 reactions without loss of activity. The urease-eggshell membranes were stable for 2 months when stored in buffer even at room temperature.

  1. pH-dependent immobilization of urease on glutathione-capped gold nanoparticles.

    PubMed

    Garg, Seema; De, Arnab; Mozumdar, Subho

    2015-05-01

    Urease is a nickel-dependent metalloenzyme that catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. Although the enzyme serves a significant role in several detoxification and analytical processes, its usability is restricted due to high cost, availability in small amounts, instability, and a limited possibility of economic recovery from a reaction mixture. Hence, there is a need to develop an efficient, simple, and reliable immobilization strategy for the enzyme. In this study, the carboxyl terminated surface of glutathione-capped gold nanoparticles have been utilized as a solid support for the covalent attachment of urease. The immobilization has been carried out at different pH conditions so as to elucidate its effect on the immobilization efficiency and enzyme bioactivity. The binding of the enzyme has been quantitatively and qualitatively analyzed through techniques like ultraviolet-visible spectroscopy, intrinsic steady state fluorescence, and circular dichorism. The bioactivity of the immobilized enzyme was investigated with respect to the native enzyme under different thermal conditions. Recyclability and shelf life studies of the immobilized enzyme have also been carried out. Results reveal that the immobilization is most effective at pH of 7.4 followed by that in an acidic medium and is least in alkaline environment. The immobilized enzyme also exhibits enhance activity in comparison to the native form at physiological temperature. The immobilized urease (on gold glutathione nanoconjugates surface) can be effectively employed for biosensor fabrication, immunoassays and as an in vivo diagnostic tool in the future.

  2. Immobilization of α-amylase onto a calix[4]arene derivative: Evaluation of its enzymatic activity.

    PubMed

    Veesar, Irshad Ali; Solangi, Imam Bakhsh; Memon, Shahabuddin

    2015-06-01

    In order to enhance the cost-effectiveness practicability of enzymes in many industries such as pharmaceutical, food, medical and some other technological processes, there is great need to immobilize them onto a solid supports. In this study, a new and efficient immobilization of α-amylase from Saccharomyces cerevisiae has been developed by using the surface functionalization of calix[4]arene as support. A glutaraldehyde-containing amino group functionalized calix[4]arene was used to immobilize α-amylase covalently. In this procedure, imide bonds are formed between amino groups on the protein and aldehyde groups on the calix[4]arene surface. The surface modified support was characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM). The effect of various preparation conditions on the immobilized α-amylase process such as immobilization time, enzyme concentration, temperature and pH were investigated. The influence of pH and temperature on the activity of free and immobilized α-amylase was also studied using starch as substrate. The optimum reaction temperature and pH value for the enzymatic conversion catalyzed by the immobilized α-amylase were 25°C and 7, respectively. Compared to the free enzyme, the immobilized α-amylase retained 85% of its original activity and exhibited significant thermal stability than the free one and excellent durability.

  3. Synthesis and heavy metal immobilization behaviors of slag based geopolymer.

    PubMed

    Yunsheng, Zhang; Wei, Sun; Qianli, Chen; Lin, Chen

    2007-05-08

    In this paper, two aspects of studies are carried out: (1) synthesis of geopolymer by using slag and metakaolin; (2) immobilization behaviors of slag based geopolymer in a presence of Pb and Cu ions. As for the synthesis of slag based geopolymer, four different slag content (10%, 30%, 50%, 70%) and three types of curing regimes (standard curing, steam curing and autoclave curing) are investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The testing results showed that geopolymer mortar containing 50% slag that is synthesized at steam curing (80 degrees C for 8h), exhibits higher mechanical strengths. The compressive and flexural strengths of slag based geopolymer mortar are 75.2 MPa and 10.1 MPa, respectively. Additionally, Infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are used to characterize the microstructure of the slag based geopolymer paste. IR spectra show that the absorptive band at 1086 cm(-1) shifts to lower wave number around 1007 cm(-1), and some six-coordinated Als transforms into four-coordination during the synthesis of slag based geopolymer paste. The resulting slag based geopolymeric products are X-ray amorphous materials. SEM observation shows that it is possible to have geopolymeric gel and calcium silicate hydrate (C-S-H) gel forming simultaneously within slag based geopolymer paste. As for immobilization of heavy metals, the leaching tests are employed to investigate the immobilization behaviors of the slag based geopolymer mortar synthesized under the above optimum condition. The leaching tests show that slag based geopolymer mortar can effectively immobilize Cu and Pb heavy metal ions, and the immobilization efficiency reach 98.5% greater when heavy metals are incorporated in the slag geopolymeric matrix in the range of 0.1-0.3%. The Pb exhibits better immobilization efficiency than the Cu in the case of large dosages of heavy metals.

  4. Immobilization of alliinase on porous aluminum oxide.

    PubMed

    Milka, P; Krest, I; Keusgen, M

    2000-08-05

    Membrane filters prepared from porous aluminum oxide (Anopore) were investigated for their potential use as a durable support for enzymes. Alliinase (EC 4.4.1.4) was chosen as a model enzyme for immobilization experiments. To allow for smooth fixation, the enzyme was immobilized indirectly by sugar-lectin binding. Monomolecular layers of the lectin concanavalin A and alliinase were applied by self-assembling processes. As an anchor for these layers, the sugar, mannan, was covalently coupled to the membrane surface. This procedure exhibits several advantages: (i) enzyme immobilization can be carried out under smooth conditions; (ii) immobilization needs little time; and (iii) protein layers may be renewed.

  5. Influence of acetylcholinesterase immobilization on the photoluminescence properties of mesoporous silicon surface

    NASA Astrophysics Data System (ADS)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2014-07-01

    Acetylcholinesterase immobilized p-type porous silicon surface was prepared by covalent attachment. The immobilization procedure was based on support surface chemical oxidation, silanization, surface activation with cyanuric chloride and finally covalent attachment of free enzyme on the cyanuric chloride activated porous silicon surface. Different pore diameter of porous silicon samples were prepared by electrochemical etching in HF based electrolyte solution and appropriate sample was selected suitable for enzyme immobilization with maximum trapping ability. The surface modification was studied through field emission scanning electron microscope, EDS, FT-IR analysis, and photoluminescence measurement by utilizing the fluctuation in the photoluminescence of virgin and enzyme immobilized porous silicon surface. Porous silicon showed strong photoluminescence with maximum emission at 643 nm and immobilization of acetylcholinesterase on porous silicon surface cause considerable increment on the photoluminescence of porous silicon material while acetylcholinesterase free counterpart did not exhibit any fluorescence in the range of 635-670 nm. The activities of the free and immobilized enzymes were evaluated by spectrophotometric method by using neostigmine methylsulfate as standard enzyme inhibitor. The immobilized enzyme exhibited considerable response toward neostigmine methylsulfate in a dose dependent manner comparable with that of its free counterpart alongside enhanced stability, easy separation from the reaction media and significant saving of enzyme. It was believed that immobilized enzyme can be exploited in organic and biomolecule synthesis possessing technical and economical prestige over free enzyme and prominence of easy separation from the reaction mixture.

  6. Polydopamine-mediated immobilization of multiple bioactive molecules for the development of functional vascular graft materials.

    PubMed

    Lee, Yu Bin; Shin, Young Min; Lee, Ji-Hye; Jun, Indong; Kang, Jae Kyeong; Park, Jong-Chul; Shin, Heungsoo

    2012-11-01

    In this study, we introduced a simple method for polydopamine-mediated immobilization of dual bioactive factors for the preparation of functionalized vascular graft materials. Polydopamine was deposited on elastic and biodegradable poly(lactic acid-co-ɛ-caprolactone) (PLCL) films, and a cell adhesive RGD-containing peptide and basic fibroblast growth factor were subsequently immobilized by simple dipping. We used an enzyme-linked immunosorbent assay and fluorescamine assay to confirm that we had stably immobilized bioactive molecules on the polydopamine-coated PLCL film in a reaction time-dependent manner. When human umbilical vein endothelial cells (HUVEC) were cultured on the prepared substrates, the number of adherent cells and proliferation of HUVEC for up to 14 days were greatest on the film immobilized with dual factors. On the other hand, the film immobilized with RGD peptide exhibited the highest migration speed compared to the other groups. The expression of cluster of differentiation 31 and von Willebrand factor, which indicates maturation of endothelial cells, was highly stimulated in the dual factor-immobilized group, and passively adsorbed factors showed a negligible effect. The immobilization of bioactive molecules inspired by polydopamine was successful, and adhesion, migration, proliferation and differentiation of HUVEC were synergistically accelerated by the presence of multiple signaling factors. Collectively, our results have demonstrated that a simple coating with polydopamine enables the immobilization of multiple bioactive molecules for preparation of polymeric functionalized vascular graft materials.

  7. Ethanol production from concentrated food waste hydrolysates with yeast cells immobilized on corn stalk.

    PubMed

    Yan, Shoubao; Chen, Xiangsong; Wu, Jingyong; Wang, Pingchao

    2012-05-01

    The aim of the present study was to examine ethanol production from concentrated food waste hydrolysates using whole cells of S. cerevisiae immobilized on corn stalks. In order to improve cell immobilization efficiency, biological modification of the carrier was carried out by cellulase hydrolysis. The results show that proper modification of the carrier with cellulase hydrolysis was suitable for cell immobilization. The mechanism proposed, cellulase hydrolysis, not only increased the immobilized cell concentration, but also disrupted the sleek surface to become rough and porous, which enhanced ethanol production. In batch fermentation with an initial reducing sugar concentration of 202.64 ± 1.86 g/l, an optimal ethanol concentration of 87.91 ± 1.98 g/l was obtained using a modified corn stalk-immobilized cell system. The ethanol concentration produced by the immobilized cells was 6.9% higher than that produced by the free cells. Ethanol production in the 14th cycle repeated batch fermentation demonstrated the enhanced stability of the immobilized yeast cells. Under continuous fermentation in an immobilized cell reactor, the maximum ethanol concentration of 84.85 g/l, and the highest ethanol yield of 0.43 g/g (of reducing sugar) were achieved at hydraulic retention time (HRT) of 3.10 h, whereas the maximum volumetric ethanol productivity of 43.54 g/l/h was observed at a HRT of 1.55 h.

  8. Immobilization of pigeonpea (Cajanus cajan) urease on DEAE-cellulose paper strips for urea estimation.

    PubMed

    Reddy K, Ravi Charan; Srivastava, Punit K; Dey, Prakash M; Kayastha, Arvind M

    2004-06-01

    Pigeonpea ( Cajanus cajan ) urease was immobilized on 1 cmx1 cm DEAE-cellulose paper strips. The optimum immobilization (51% activity) was observed at 4 degrees C, with a protein concentration of 1.0 mg/strip. The apparent optimum pH shifted from 7.3 to 6.8. Immobilized urease showed an optimal stability temperature of 67 degrees C, compared with 47 degrees C for the soluble urease. Time-dependent kinetics of the thermal inactivation of the immobilized urease were examined and found to be monophasic as compared with the soluble enzyme, which was biphasic. The Michaelis constant ( K (m)) for the DEAE-cellulose-immobilized urease was found to be 4.75 mM, 1.5 times higher than the soluble enzyme. Immobilized strips stored at 4 degrees C showed an increased half-life ( t (1/2)=150 days). There was practically no leaching of the enzyme from the immobilized strips over a period of 2 weeks. These strips were used for estimating the urea content of blood samples; the results obtained matched well with those obtained in a clinical laboratory through an Autoanalyzer(R) (Zydus Co., Rome, Italy). The easy availability of pigeonpea urease, the ease of its immobilization on DEAE-cellulose strips and the significantly lower cost of urease described in the present study makes it a suitable product for future applications in diagnostics.

  9. Graphene immobilized enzyme/polyethersulfone mixed matrix membrane: Enhanced antibacterial, permeable and mechanical properties

    NASA Astrophysics Data System (ADS)

    Duan, Linlin; Wang, Yuanming; Zhang, Yatao; Liu, Jindun

    2015-11-01

    Enzyme immobilization has been developed to address lots of issues of free enzyme, such as instability, low activity and difficult to retain. In this study, graphene was used as an ideal carrier for lysozyme immobilization, including graphene oxide (GO) immobilized lysozyme (GO-Ly) and chemically reduced graphene oxide (CRGO) immobilized lysozyme (CRGO-Ly). Herein, lysozyme as a bio-antibacterial agent has excellent antibacterial performance and the products of its catalysis are safety and nontoxic. Then the immobilized lysozyme materials were blended into polyethersulfone (PES) casting solution to prepare PES ultrafiltration membrane via phase inversion method. GO and CRGO were characterized by Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectrum (UV), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and the immobilized lysozyme composites were observed by fluorescent microscopy. The results revealed that GO and CRGO were successfully synthesized and lysozyme was immobilized on their surfaces. The morphology, hydrophilicity, mechanical properties, separation properties and antibacterial activity of the hybrid membranes were characterized in detail. The hydrophilicity, water flux and mechanical strength of the hybrid membranes were significantly enhanced after adding the immobilized lysozyme. In the antibacterial experiment, the hybrid membranes exhibited an effective antibacterial performance against Escherichia coli (E. coli).

  10. Improved performance of α-amylase immobilized on poly(glycidyl methacrylate-co-ethylenedimethacrylate) beads.

    PubMed

    He, Tian; Tian, Yong-Le; Qi, Liang; Zhang, Jing; Zhang, Zhi-Qi

    2014-04-01

    α-Amylase was successfully immobilized onto poly(glycidyl methacrylate-co-ethylenedimethacrylate) (PGMA/EDMA) beads with high immobilization efficiency of 87.8%. PGMA/EDMA beads with a relatively uniform diameter of 2-3 μm were prepared by single-step swelling polymerization. After amination with ethanediamine and activation with glutaraldehyde, PGMA/EDMA beads showed commendable α-amylase immobilization capacity of 35.1 mg g(-1) carrier. Compared with free form, immobilized α-amylase had increasement of 12.94 mg mL(-1) for Km and 0.124 mmol mL(-1) min(-1) for Vmax, improved acid resistance (the optimal pH from 7 to 5), presented better thermal stability by retaining 61% activity than 40% at 90 °C, and displayed high operational reusability by retaining 58% of its initial activity after nine uses. Moreover, less than 10% of the free enzyme and more than 80% of the immobilized enzyme retained activity after 180 min pre-incubation at 50 °C. The easy modification, high immobilization efficiency and good properties of immobilized α-amylase in the present study indicate that PGMA/EDMA beads are suitable for α-amylase immobilization. The enhancement of acid resistance and thermo stability is doubtless of benefit for the industrial use of α-amylase.

  11. Tunable control of antibody immobilization using electric field

    PubMed Central

    Emaminejad, Sam; Javanmard, Mehdi; Gupta, Chaitanya; Chang, Shuai; Davis, Ronald W.; Howe, Roger T.

    2015-01-01

    The controlled immobilization of proteins on solid-state surfaces can play an important role in enhancing the sensitivity of both affinity-based biosensors and probe-free sensing platforms. Typical methods of controlling the orientation of probe proteins on a sensor surface involve surface chemistry-based techniques. Here, we present a method of tunably controlling the immobilization of proteins on a solid-state surface using electric field. We study the ability to orient molecules by immobilizing IgG molecules in microchannels while applying lateral fields. We use atomic force microscopy to both qualitatively and quantitatively study the orientation of antibodies on glass surfaces. We apply this ability for controlled orientation to enhance the performance of affinity-based assays. As a proof of concept, we use fluorescence detection to indirectly verify the modulation of the orientation of proteins bound to the surface. We studied the interaction of fluorescently tagged anti-IgG with surface immobilized IgG controlled by electric field. Our study demonstrates that the use of electric field can result in more than 100% enhancement in signal-to-noise ratio compared with normal physical adsorption. PMID:25650429

  12. Preparation of magnetite-fullerene nanocomposite with enzyme immobilization.

    PubMed

    Kalska-Szostko, B; Rogowska, M

    2012-09-01

    This study presents modification of magnetite nanoparticles and fullerene for biocompatibility. It show also specific fabrication of magnetite-carbon nanocomposite with immobilized biomolecule. The composites were created by joining individual components step-by-step manner (fullerene to magnetite and glucose oxidase or glucose oxidase to magnetite and fullerene). The resulting nanocomposites were characterized by infrared spectroscopy (IR) and transmission electron microscopy (TEM).

  13. Erosion depth of sand from an immobile gravel bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract This study was conducted to provide information on the depth of erosion of sand (D50 = 0.3, 0.9 mm) from immobile gravel (D50 = 36.1 mm) under steady uniform flows with bed shear stresses from 0.1 to 0.9 of that required to entrain the gravel. This situation, often encountered downstream o...

  14. Drug absorption in vitro model: filter-immobilized artificial membranes. 2. Studies of the permeability properties of lactones in Piper methysticum Forst.

    PubMed

    Avdeef, A; Strafford, M; Block, E; Balogh, M P; Chambliss, W; Khan, I

    2001-12-01

    The assessment of transport properties of 23 drug and natural product molecules was made using the in vitro model based on filter-immobilized artificial membranes (filter-IAM), assembled from phosphatidylcholine in dodecane, in buffer solutions at pH 7.4. Five of the compounds were lactones extracted from the roots of the kava-kava plant. Experiments were designed to test the effects of stirring (0-600 rpm) during assays and the effects of varying the assay times (2-15 h). The highly mobile kava lactones permeated in the order dihydromethisticin (40)>yangonin (37)>kavain (34)>methisticin (32)>desmethoxyyangonin (26), the numbers in parentheses being the measured effective permeabilities in units of 10(-6) cm/s. By comparison, commercial drugs ranked: phenazopyridine (35)>testosterone (19)>propranolol (13)>ketoconazole (6.3)>piroxicam (2.2)>caffeine (1.7)>metoprolol (0.8)>terbutaline (0.01). In addition to permeability measurements, membrane retention of compounds was determined. Yangonin, desmethoxyyangonin, ketoconazole, and phenazopyridine were more than 60% retained by the artificial membranes containing phospholipids. Stirring during assay significantly increased the observed permeabilities for highly mobile molecules, but had minimal impact on the poorly permeable molecules. The influence of hydrogen bonding was explored by determining permeabilities using filters coated with dodecane free of phospholipids. In the filter-IAM method, concentrations were determined by microtitre plate UV spectrophotometry and by LC-MS. Higher-throughput was achieved with direct UV by the use of 96-well microtitre plate formats and with LC-MS by the use of cassette dosing (five-in-one).

  15. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO₂ nanoparticles from aqueous media.

    PubMed

    Shaker, Medhat A; Yakout, Amr A

    2016-02-05

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51±3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, (1)H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r(2)) and non-linear Chi-square (χ(2)) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

  16. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO2 nanoparticles from aqueous media

    NASA Astrophysics Data System (ADS)

    Shaker, Medhat A.; Yakout, Amr A.

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51 ± 3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, 1H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r2) and non-linear Chi-square (χ2) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

  17. Immobilized lipid-bilayer materials

    DOEpatents

    Sasaki, Darryl Y.; Loy, Douglas A.; Yamanaka, Stacey A.

    2000-01-01

    A method for preparing encapsulated lipid-bilayer materials in a silica matrix comprising preparing a silica sol, mixing a lipid-bilayer material in the silica sol and allowing the mixture to gel to form the encapsulated lipid-bilayer material. The mild processing conditions allow quantitative entrapment of pre-formed lipid-bilayer materials without modification to the material's spectral characteristics. The method allows for the immobilization of lipid membranes to surfaces. The encapsulated lipid-bilayer materials perform as sensitive optical sensors for the detection of analytes such as heavy metal ions and can be used as drug delivery systems and as separation devices.

  18. Pineapple stem bromelain immobilized on different supports: catalytic properties in model wine.

    PubMed

    Ilaria, Benucci; Marco, Esti; Katia, Liburdi; Maria Vittoria, Garzillo Anna

    2012-01-01

    Bromelain from pineapple stem has been covalently immobilized on different supports to select the more efficient biocatalyst that should be applied toward unstable proteins in real white wine. In this preliminary study, catalytic properties of different immobilized bromelain forms were compared under wine-like conditions, against a synthetic substrate (Bz-Phe-Val-Arg-pNA).Covalent immobilization affected protease kinetic properties, even if all immobilized forms presented both a better substrate affinity and higher half-life (with the exception of a few procedures) with respect to the free enzyme. Stem bromelain was successfully immobilized on chitosan beads without glutaraldehyde thus yielding a food-safe and promising biocatalyst for unstable real wine future application.

  19. Optimization of catechol production by membrane-immobilized polyphenol oxidase: a modeling approach.

    PubMed

    Boshoff, A; Burton, M H; Burton, S G

    2003-07-05

    Although previous research has focused on phenol removal efficiencies using polyphenol oxidase in nonimmobilized and immobilized forms, there has been little consideration of the use of polyphenol oxidase in a biotransformation system for the production of catechols. In this study, polyphenol oxidase was successfully immobilized on various synthetic membranes and used to convert phenolic substrates to catechol products. A neural network model was developed and used to model the rates of substrate utilization and catechol production for both nonimmobilized and immobilized polyphenol oxidase. The results indicate that the biotransformation of the phenols to their corresponding catechols was strongly influenced by the immobilization support, resulting in differing yields of catechols. Hydrophilic membranes were found to be the most suitable immobilization supports for catechol production. The successful biocatalytic production of 3-methylcatechol, 4-methylcatechol, catechol, and 4-chlorocatechol is demonstrated.

  20. Immobilization of a Plant Lipase from Pachira aquatica in Alginate and Alginate/PVA Beads

    PubMed Central

    Bonine, Bárbara M.; Polizelli, Patricia Peres; Bonilla-Rodriguez, Gustavo O.

    2014-01-01

    This study reports the immobilization of a new lipase isolated from oleaginous seeds of Pachira aquatica, using beads of calcium alginate (Alg) and poly(vinyl alcohol) (PVA). We evaluated the morphology, number of cycles of reuse, optimum temperature, and temperature stability of both immobilization methods compared to the free enzyme. The immobilized enzymes were more stable than the free enzyme, keeping 60% of the original activity after 4 h at 50°C. The immobilized lipase was reused several times, with activity decreasing to approximately 50% after 5 cycles. Both the free and immobilized enzymes were found to be optimally active between 30 and 40°C. PMID:24818012

  1. Enhanced activity of immobilized dimethylmaleic anhydride-protected poly- and monoclonal antibodies.

    PubMed

    Hadas, E; Koppel, R; Schwartz, F; Raviv, O; Fleminger, G

    1990-06-27

    The effect of reversible protection of the free amino groups of poly- and monoclonal antibodies by dimethylmaleic anhydride on their binding activity following immobilization onto various carriers was studied. The treatment with dimethylmaleic anhydride resulted in a 1.6-1.8-fold increase in the activity of immobilized goat anti-mouse immunoglobulin antibody immobilized onto different epoxy containing carriers and a 3-10.7-fold increase in the activity of immobilized monoclonal antibodies specific for carboxypeptidase A. The increase in activity was most pronounced at low antigen to carrier loads and over a wide range of modifier to protein ratios. The application of reversible protection of antibodies may permit the development of highly active immobilized antibody preparations for use in immunoaffinity purification.

  2. Effect of consecutive cooling and immobilization on catecholamine metabolism in rat tissues

    NASA Technical Reports Server (NTRS)

    Matlina, E. S.; Waysman, S. M.; Zaydner, I. G.; Kogan, B. M.; Nozdracheva, L. V.

    1979-01-01

    The combined effect of two stressor stimuli--cooling and immobilization--acting successively on the sympathetic-adrenaline system was studied experimentally in rats that were cooled for 8 hours at 7 C on the first day and immobilized for 6 hours on the next day. The biochemical and histochemical methods used and the experimental technique involved are described in detail. The following conclusions were formulated: (1) the successive action of cooling and immobilization results in a stronger decrease in the adrenaline and noradrenaline content in the adrenal gland than that which could be due to a simple summation of the cooling and immobilization effects; (2) successive cooling and immobilization are followed by activation of catecholamine synthesis in the adrenal gland; and (3) 1-DOPA administration (45 mg/kg 3 times in 2 days) intraabdominally activated catecholamine synthesis in the adrenal glands in both the control and test animals.

  3. Immobilization of a Bacterial Cytochrome P450 Monooxygenase System on a Solid Support.

    PubMed

    Tan, Cheau Yuaan; Hirakawa, Hidehiko; Suzuki, Risa; Haga, Tomoaki; Iwata, Fumiya; Nagamune, Teruyuki

    2016-11-21

    Bacterial cytochrome P450s (P450s), which catalyze regio- and stereoselective oxidations of hydrocarbons with high turnover rates, are attractive biocatalysts for fine chemical production. Enzyme immobilization is needed for cost-effective industrial manufacturing. However, immobilization of P450s is difficult because electron-transfer proteins are involved in catalysis and anchoring these can prevent them from functioning as shuttle molecules for carrying electrons. We studied a heterotrimeric protein-mediated co-immobilization of a bacterial P450, and its electron-transfer protein and reductase. Fusion with subunits of a heterotrimeric Sulfolobus solfataricus proliferating cell nuclear antigen (PCNA) enabled immobilization of the three proteins on a solid support. The co-immobilized enzymes catalyzed monooxygenation because the electron-transfer protein fused to PCNA via a single peptide linker retained its electron-transport function.

  4. Fabrication of anticoagulation layer on titanium surface by sequential immobilization of poly (ethylene glycol) and albumin.

    PubMed

    Pan, Chang-Jiang; Hou, Yan-Hua; Zhang, Bin-Bin; Zhang, Lin-Cai

    2014-01-01

    This paper presents a simple method to sequentially immobilize poly (ethylene glycol) (PEG) and albumin on titanium surface to enhance the blood compatibility. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis indicated that PEG and albumin were successfully immobilized on the titanium surface. Water contact angle results showed a better hydrophilic surface after the immobilization. The immobilized PEG or albumin can not only obviously prevent platelet adhesion and activation but also prolong activated partial thromboplastin time (APTT), leading to the improved anticoagulation. Moreover, immobilization of albumin on PEG-modified surface can further improve the anticoagulation. The approach in the present study provides an effective and efficient method to improve the anticoagulation of blood-contact biomedical devices such as coronary stents.

  5. A Versatile Microarray Immobilization Strategy Based on a Biorthogonal Reaction Between Tetrazine and Trans-Cyclooctene.

    PubMed

    Wang, Ping; Gao, Liqian; Lei, Haipeng; Lee, Su Seong; Yao, Shao Q; Sun, Hongyan

    2017-01-01

    Given its increasing importance in transforming biomedical research in recent years, microarray technology has become highly popular as a powerful screening platform in detecting biomolecule interactions, discovering new inhibitors, and identifying biomarkers as well as diagnosing disease. The success of microarray technology in various biological applications is highly dependent on the accessibility, the functionality, and the density of the surface bound biomolecules. Therefore, compound immobilization represents a critical step for the successful implementation of microarray screening. Herein we describe a fast and site-specific microarray immobilization approach by using trans-cyclooctene-tetrazine ligation. This approach not only ensures fast immobilization and uniform display of biomolecules, but also allows the optimum orientation of biomolecules after immobilization. All these excellent properties facilitate subsequent interactions of the biomolecules and their interacting partners during the screening process. We envision that the immobilization strategy described here can find useful applications in many other microarray related studies.

  6. Immobilization of bacterial proteases on water-solved polymer by means of electron beam

    NASA Astrophysics Data System (ADS)

    Gonchar, A. M.; Auslender, V. L.

    1996-12-01

    Possibility of electron beam usage for proteases' immobilization on 1,4-polyalkylene oxide (1,4-PAO) was studied to obtain biologically active complex for multi-purpose usage. It is shown that immobilization of Bacillus Subtilis protease takes place due to free-radical linking of enzyme and carrier with formation of mycellium-like structures. Immobilization improves heat resistance of enzyme up to 60°C without substrate and up to 80°C in presence of substrate, widens range of pH activity in comparison with non-immobilized forms. Immobilized proteases do not contain peroxides or long-live radicals. Our results permitted to create technologies for production of medical and veterinary preparations, active components for wool washing agents and leather fabrication technology.

  7. Immobilization of Streptomyces thermotolerans 11432 on polyurethane foam to improve production of acetylisovaleryltylosin.

    PubMed

    Zhu, Hongji; Wang, Weihua; Liu, Jiaheng; Caiyin, Qinggele; Qiao, Jianjun

    2015-01-01

    In this study, polyurethane foam (PUF) was chemically treated to immobilize Streptomyces thermotolerans 11432 for semi-continuous production of acetylisovaleryltylosin (AIV). Based on experimental results, positive cross-linked PUF (PCPUF) was selected as the most effective carrier according to immobilized cell mass. The effect of adsorption time on immobilized mass was investigated. AIV concentration (33.54 mg/l) in batch fermentations with immobilized cells was higher than with free cells (20.34 mg/l). In repeated batch fermentations with immobilized S. thermotolerans 11432 using PCPUF cubes, high AIV concentrations and conversion rates were attained, ranging from 25.56 to 34.37 mg/l and 79.93 to 86.31 %, respectively. Significantly, this method provides a feasible strategy for efficient AIV production and offers the potential for large-scale production.

  8. Stabilization of α-amylase by using anionic surfactant during the immobilization process

    NASA Astrophysics Data System (ADS)

    El-Batal, A. I.; Atia, K. S.; Eid, M.

    2005-10-01

    This work describes the entrapment of α-amylase into butylacrylate-acrylic acid copolymer (BuA/AAc) using γ irradiation. The effect of an anionic surfactant (AOT), the reuse efficiency, and kinetic behavior of immobilized α-amylase were studied. Covering of α-amylase with bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) made the enzyme more stable than the uncovered form. The hydrolytic activity of the pre-coated immobilized α-amylase was increased below the critical micelle concentration (cmc) (10 mmol/L). The results showed an increase in the relative activity with increase in the degree of hydration. The pre-coated immobilized α-amylase showed a higher k/K and lower activation energy compared to the free and uncoated-immobilized preparation, respectively. The results suggest that the immobilization of α-amylase is a potentially useful approach for commercial starch hydrolysis in two-phase systems.

  9. Cellulases immobilization on chitosan-coated magnetic nanoparticles: application for Agave Atrovirens lignocellulosic biomass hydrolysis.

    PubMed

    Sánchez-Ramírez, Jaquelina; Martínez-Hernández, José L; Segura-Ceniceros, Patricia; López, Guillermo; Saade, Hened; Medina-Morales, Miguel A; Ramos-González, Rodolfo; Aguilar, Cristóbal N; Ilyina, Anna

    2017-01-01

    In the present study, Trichoderma reesei cellulase was covalently immobilized on chitosan-coated magnetic nanoparticles using glutaraldehyde as a coupling agent. The average diameter of magnetic nanoparticles before and after enzyme immobilization was about 8 and 10 nm, respectively. The immobilized enzyme retained about 37 % of its initial activity, and also showed better thermal and storage stability than free enzyme. Immobilized cellulase retained about 80 % of its activity after 15 cycles of carboxymethylcellulose hydrolysis and was easily separated with the application of an external magnetic field. However, in this reaction, K m was increased eight times. The immobilized enzyme was able to hydrolyze lignocellulosic material from Agave atrovirens leaves with yield close to the amount detected with free enzyme and it was re-used in vegetal material conversion up to four cycles with 50 % of activity decrease. This provides an opportunity to reduce the enzyme consumption during lignocellulosic material saccharification for bioethanol production.

  10. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

    PubMed

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-02-02

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness.

  11. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

    PubMed Central

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  12. Covalent attachment of cholesterol oxidase and horseradish peroxidase on perlite through silanization: activity, stability and co-immobilization.

    PubMed

    Torabi, Seyed-Fakhreddin; Khajeh, Khosro; Ghasempur, Salehe; Ghaemi, Nasser; Siadat, Seyed-Omid Ranaei

    2007-08-31

    In the present work, co-immobilization of cholesterol oxidase (COD) and horseradish peroxidase (POD) on perlite surface was attempted. The surface of perlite were activated by 3-aminopropyltriethoxysilane and covalently bonded with COD and POD via glutaraldehyde. Enzymes activities have been assayed by spectrophotometric technique. The stabilities of immobilized COD and POD to pH were higher than those of soluble enzymes and immobilization shifted optimum pH of enzymes to the lower pH. Heat inactivation studies showed improved thermostability of the immobilized COD for more than two times, but immobilized POD was less thermostable than soluble POD. Also activity recovery of immobilized COD was about 50% since for immobilized POD was 11%. The K(m) of immobilized enzymes was found slightly lower than that of soluble enzymes. Immobilized COD showed inhibition in its activity at high cholesterol concentration which was not reported for soluble COD before. Co-immobilized enzymes retained 65% of its initial activity after 20 consecutive reactor batch cycles.

  13. Effect of low-level helium-neon laser therapy on histological and ultrastructural features of immobilized rabbit articular cartilage.

    PubMed

    Bayat, Mohammad; Ansari, Enayatallah; Gholami, Narges; Bayat, Aghdas

    2007-05-25

    The present study investigates whether low-level helium-neon laser therapy can increase histological parameters of immobilized articular cartilage in rabbits or not. Twenty five rabbits were divided into three groups: the experiment group, which received low-level helium-neon laser therapy with 13J/cm(2) three times a week after immobilization of their right knees; the control group which did not receive laser therapy after immobilization of their knees; and the normal group which received neither immobilization nor laser therapy. Histological and electron microscopic examinations were performed at 4 and 7 weeks after immobilization. Depth of the chondrocyte filopodia in four-week immobilized experiment group, and depth of articular cartilage in seven-week immobilized experiment group were significantly higher than those of relevant control groups (exact Fisher test, p=0.001; student's t-test, p=0.031, respectively). The surfaces of articular cartilages of the experiment group were relatively smooth, while those of the control group were unsmooth. It is therefore concluded that low-level helium-neon laser therapy had significantly increased the depth of the chondrocyte filopodia in four-week immobilized femoral articular cartilage and the depth of articular cartilage in seven-week immobilized knee in comparison with control immobilized articular cartilage.

  14. Cascade catalysis in membranes with enzyme immobilization for multi-enzymatic conversion of CO2 to methanol.

    PubMed

    Luo, Jianquan; Meyer, Anne S; Mateiu, R V; Pinelo, Manuel

    2015-05-25

    Facile co-immobilization of enzymes is highly desirable for bioconversion methods involving multi-enzymatic cascade reactions. Here we show for the first time that three enzymes can be immobilized in flat-sheet polymeric membranes simultaneously or separately by simple pressure-driven filtration (i.e. by directing membrane fouling formation), without any addition of organic solvent. Such co-immobilization and sequential immobilization systems were examined for the production of methanol from CO2 with formate dehydrogenase (FDH), formaldehyde dehydrogenase (FaldDH) and alcohol dehydrogenase (ADH). Enzyme activity was fully retained by this non-covalent immobilization strategy. The two immobilization systems had similar catalytic efficiencies because the second reaction (formic acid→formaldehyde) catalyzed by FaldDH was found to be the cascade bottleneck (a threshold substrate concentration was required). Moreover, the trade-off between the mitigation of product inhibition and low substrate concentration for the adjacent enzymes probably made the co-immobilization meaningless. Thus, sequential immobilization could be used for multi-enzymatic cascade reactions, as it allowed the operational conditions for each single step to be optimized, not only during the enzyme immobilization but also during the reaction process, and the pressure-driven mass transfer (flow-through mode) could overcome the diffusion resistance between enzymes. This study not only offers a green and facile immobilization method for multi-enzymatic cascade systems, but also reveals the reaction bottleneck and provides possible solutions for the bioconversion of CO2 to methanol.

  15. 3D-Printed Small-Animal Immobilizer for Use in Preclinical Radiotherapy.

    PubMed

    McCarroll, Rachel E; Rubinstein, Ashley E; Kingsley, Charles V; Yang, Jinzhong; Yang, Peiying; Court, Laurence E

    2015-09-01

    We have designed a method for immobilizing the subjects of small-animal studies using a study group-specific 3D-printed immobilizer that significantly reduces interfraction rotational variation. A cone-beam CT scan acquired from a single specimen in a study group was used to create a 3D-printed immobilizer that can be used for all specimens in the same study group. 3D printing allows for the incorporation of study-specific features into the immobilizer design, including geometries suitable for use in MR and CT scanners, holders for fiducial markers, and anesthesia nose cones of various sizes. Using metrics of rotational setup variations, we compared the current setup in our small-animal irradiation system, a half-pipe bed, with the 3D-printed device. We also assessed translational displacement within the immobilizer. The printed design significantly reduced setup variation, with average reductions in rotational displacement of 76% ± 3% (1.57 to 0.37°) in pitch, 78% ± 3% (1.85 to 0.41°) in yaw, and 87% ± 3% (5.39 to 0.70°) in roll. Translational displacement within the printed immobilizer was less than 1.5 ± 0.3 mm. This method of immobilization allows for repeatable setup when using MR or CT scans for the purpose of radiotherapy, streamlines the workflow, and places little burden on the study subjects.

  16. Technetium Immobilization Forms Literature Survey

    SciTech Connect

    Westsik, Joseph H.; Cantrell, Kirk J.; Serne, R. Jeffrey; Qafoku, Nikolla

    2014-05-01

    Of the many radionuclides and contaminants in the tank wastes stored at the Hanford site, technetium-99 (99Tc) is one of the most challenging to effectively immobilize in a waste form for ultimate disposal. Within the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the Tc will partition between both the high-level waste (HLW) and low-activity waste (LAW) fractions of the tank waste. The HLW fraction will be converted to a glass waste form in the HLW vitrification facility and the LAW fraction will be converted to another glass waste form in the LAW vitrification facility. In both vitrification facilities, the Tc is incorporated into the glass waste form but a significant fraction of the Tc volatilizes at the high glass-melting temperatures and is captured in the off-gas treatment systems at both facilities. The aqueous off-gas condensate solution containing the volatilized Tc is recycled and is added to the LAW glass melter feed. This recycle process is effective in increasing the loading of Tc in the LAW glass but it also disproportionally increases the sulfur and halides in the LAW melter feed which increases both the amount of LAW glass and either the duration of the LAW vitrification mission or the required supplemental LAW treatment capacity.

  17. Leukocyte responses to immobilized patterns of CXCL8.

    PubMed

    Girrbach, Maria; Rink, Ina; Ladnorg, Tatjana; Azucena, Carlos; Heißler, Stefan; Haraszti, Tamás; Schepers, Ute; Schmitz, Katja

    2016-06-01

    The attachment of neutrophils to the endothelial surface and their migration towards the site of inflammation following chemokine gradients play an essential role in the innate immune response. Chemokines adhere to glycosaminoglycans on the endothelial surface to be detected by leukocytes and trigger their movement along surface- bound gradients in a process called haptotaxis. In assays to systematically study the response of leukocytes to surface-bound compounds both the spatial arrangement of the compound as well as the mode of immobilization need to be controlled. In this study microcontact printing was employed to create patterns of hydrophobic or functionalized thiols on gold-coated glass slides and CXCL8 was immobilized on the thiol coated areas using three different strategies. Human neutrophils adhered to the CXCL8-coated lines but not to the PEG-coated background. We could show that more cells adhered to CXCL8 adsorbed to hydrophobic octadecanethiol than on CXCL8 covalently bound to amino undecanethiol or CXCL8 specifically bound to immobilized heparin on aminothiol. Likewise general cell activity such as lamellipodia formation and random migration were most pronounced for CXCL8 adsorbed on a hydrophobic surface which may be attributed to the larger amounts of protein immobilized on this type of surface.

  18. Substrate specificity and enzyme recycling using chitosan immobilized laccase.

    PubMed

    Skoronski, Everton; Fernandes, Mylena; Magalhães, Maria de Lourdes Borba; da Silva, Gustavo Felippe; João, Jair Juarez; Soares, Carlos Henrique Lemos; Júnior, Agenor Fúrigo

    2014-10-17

    The immobilization of laccase (Aspergillus sp.) on chitosan by cross-linking and its application in bioconversion of phenolic compounds in batch reactors were studied. Investigation was performed using laccase immobilized via chemical cross-linking due to the higher enzymatic operational stability of this method as compared to immobilization via physical adsorption. To assess the influence of different substrate functional groups on the enzyme's catalytic efficiency, substrate specificity was investigated using chitosan-immobilized laccase and eighteen different phenol derivatives. It was observed that 4-nitrophenol was not oxidized, while 2,5-xylenol, 2,6-xylenol, 2,3,5-trimethylphenol, syringaldazine, 2,6-dimetoxyphenol and ethylphenol showed reaction yields up 90% at 40 °C. The kinetic of process, enzyme recyclability and operational stability were studied. In batch reactors, it was not possible to reuse the enzyme when it was applied to syringaldazne bioconversion. However, when the enzyme was applied to bioconversion of 2,6-DMP, the activity was stable for eight reaction batches.

  19. Surface and Interface Control on Photochemically Initiated Immobilization

    SciTech Connect

    Liu, Li; Engelhard, Mark H.; Yan, Mingdi

    2006-11-01

    Surface and interface properties are important in controlling the yield and efficiency of the photochemically initiated immobilization. Using a silane-functionalized perfluorophenylazide (PFPA-silane) as the photoactive crosslinker, the immobilization of polymers was studied by adjusting the density of the surface azido groups. Dilution of the photolinker resulted in a gradual decrease in the density of surface azido groups as well as the thickness of the immobilized film. When a non-photoactive silane was added to PFPA-silane, the film thickness decreased more rapidly, indicating that the additive competed with PFPA-silane and effectively reduced the density of the surface azido groups. The effect of surface topography was studied by adding a non-photoactive silane with either a shorter (n-propyltrimethoxysilane (PTMS)) or a longer spacer (n-octadecyltrimethoxysilane (ODTMS)). In most cases the long chain ODTMS shielded the surface azido groups resulting in more rapid decrease in film thickness as compared to PTMS treated under the same conditions. As the density of the surface azido groups decreased, the immobilized polymer changed from smooth films to patched structures, and eventually single polymer molecules.

  20. Immobilization of microalgae for biosorption and degradation of butyltin chlorides.

    PubMed

    Zhang, L; Huang, G; Yu, Y

    1998-07-01

    Since the discovery of their biocidal properties in the 1950s, organotin compounds have found a large spectrum of industrial applications such as wood and textile preservatives, fungicides and pesticides, and antifouling paint on ships and fishing equipment. The fate and environmental impact of butyltins have been the subjects of a large body of research in the last decades. Biosorption and degradation of butyltin compounds by immobilized microalgae chlorella were studied in this paper, aiming to find an alternative way to solve organotin pollution problem. Chlorella emersonii cells were entrapped in a calcium aginate matrix. The cell growth rates, respiratory rate and chlorophyll a content were studied and compared. Results showed that immobilized chlorella had increased respiratory and growth rates, and almost equal chlorophyll a content when compared with free cells. Cell leakage was slight during the 20-day experimental period Cell leakage from the matrix was unrelated to cell growth within the matrix. Immobilized chlorella was applied to deal with butytin contaminated aquatic solutions. Immobilized chlorella had increased degradation rates of tri-, di-, and mono-butyltin chlorides in aquatic solutions, and lower biological accumulation factors on cells, than free cells, which indicates a potential use for tackleing organotin polluted water body.

  1. Plutonium Immobilization Can Loading Equipment Review

    SciTech Connect

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.

    1998-05-01

    This report lists the operations required to complete the Can Loading steps on the Pu Immobilization Plant Flow Sheets and evaluates the equipment options to complete each operation. This report recommends the most appropriate equipment to support Plutonium Immobilization Can Loading operations.

  2. Immobilization of enzyme on chiral polyelectrolyte surface.

    PubMed

    Ding, Chao; Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

    2017-02-01

    Chiral D- and L-N-acryloyl aspartic acid (NAsp) polyelectrolyte (PE) surfaces with similar chemical compositions and physical properties but opposite chirality are designed for enzyme immobilization. Enzymes immobilized onto the chiral PE surfaces present high chiral preference, namely L-NAsp PE surface can keep most of the catalytic activity of the immobilized enzymes, however, for enzymes immobilized on D-NAsp PE surface a large decrease in catalytic activity occurred which was 11 times lower compared with L-NAsp PE surface. This phenomenon of chiral effect on enzymes immobilization can be explained by attenuated total reflectance (ATR) and circular dichroism (CD) results. The results exhibited that L-NAsp PE surface could preserve most of the secondary structures of immobilized enzymes while on D-NAsp PE surface with a large conformation alteration. These chiral surface induced differences after enzyme immobilization can be further used for logic operation. These results imply a novel strategy for the design of new enzymes immobilization materials based on the chiral effect and expand the applications of enzymes in biochips, chemical transformations and chiral biodevices.

  3. Helicopter immobilization of elk in southcentral Washington

    SciTech Connect

    McCorquodale, S.M.; Eberhardt, L.E. ); Petron, S.E. )

    1988-01-01

    Free-ranging elk are commonly immobilized for research or management by rifle-fired darts shot from a helicopter. Compounds used for this purpose have included succinylcholine chloride (succinylcholine), etorphine hydrochloride (etorphine), and xylazine hydrochloride (xylazine). To assess the efficacy of various immobilizing drugs used in helicopter applications, we darted 38 elk from a helicopter on the Arid Lands Ecology Reserve, Washington from 1983 to 1987. We used either succinylcholine, etorphine hydrochloride, or xylazine hydrochloride a primary immobilants. Unsuccessful immobilizations were most common in elk darted with succinylcholine. Yohimbine was used to reverse xylazine immobilizations. The use of xylazine and yohimbine provides an efficient, cost-effective alternative to etorphine, diprenorphine immobilization and reversal in elk while increasing handler safety. Etorphine appeared to be the best immobilant when extended pain-producing procedures (such as surgical telemetry implantation) are planned because it induced the longest and deepest anesthesia. When the potential to lose contact with darted animals exist, we believe succinylcholine may be the preferred immobilant because of rapid, spontaneous recovery.

  4. The effects of joint immobilization on articular cartilage of the knee in previously exercised rats

    PubMed Central

    Maldonado, Diogo Correa; da Silva, Marcelo Cavenaghi Pereira; Neto, Semaan El-Razi; Souza, Mônica Rodrigues; Souza, Romeu Rodrigues

    2013-01-01

    Studies have determined the effects of joint immobilization on the articular cartilage of sedentary animals, but we are not aware of any studies reporting the effects of joint immobilization in previously trained animals. The objective of the present study was to determine whether exercise could prevent degeneration of the articular cartilage that accompanies joint immobilization. We used light microscopy to study the thickness, cell density, nuclear size, and collagen density of articular cartilage of the femoral condyle of Wistar rats subjected to aerobic physical activity on an adapted treadmill five times per week. Four groups of Wistar rats were used: a control group (C), an immobilized group (I), an exercised group (E), and an exercised and then immobilized group (EI). The right knee joints from rats in groups I and EI were immobilized at 90 °C of flexion using a plastic cast for 8 weeks. Cartilage thickness decreased significantly in group I (mean, 120.14 ± 15.6 μm, P < 0.05), but not in group EI (mean, 174 ± 2.25), and increased significantly in group E (mean, 289.49 ± 9.15) compared with group C (mean, 239.20 ± 6.25). The same results were obtained for cell density, nuclear size, and collagen density (in all cases, P < 0.05). We concluded that exercise can prevent degenerative changes in femoral articular cartilage caused by immobilization of the knee joint. PMID:23480127

  5. Immobilized fluid membranes for gas separation

    SciTech Connect

    Liu, Wei; Canfield, Nathan L; Zhang, Jian; Li, Xiaohong Shari; Zhang, Jiguang

    2014-03-18

    Provided herein are immobilized liquid membranes for gas separation, methods of preparing such membranes and uses thereof. In one example, the immobilized membrane includes a porous metallic host matrix and an immobilized liquid fluid (such as a silicone oil) that is immobilized within one or more pores included within the porous metallic host matrix. The immobilized liquid membrane is capable of selective permeation of one type of molecule (such as oxygen) over another type of molecule (such as water). In some examples, the selective membrane is incorporated into a device to supply oxygen from ambient air to the device for electrochemical reactions, and at the same time, to block water penetration and electrolyte loss from the device.

  6. Immobilized Lactase in the Biochemistry Laboratory

    NASA Astrophysics Data System (ADS)

    Allison, Matthew J.; Bering, C. Larry

    1998-10-01

    Immobilized enzymes have many practical applications. They may be used in clinical, industrial, and biotechnological laboratories and in many clinical diagnostic kits. For educational purposes, use of immobilized enzymes can easily be taught at the undergraduate or even secondary level. We have developed an immobilized enzyme experiment that combines many practical techniques used in the biochemistry laboratory and fits within a three-hour time frame. In this experiment, lactase from over-the-counter tablets for patients with lactose intolerance is immobilized in polyacrylamide, which is then milled into small beads and placed into a chromatography column. A lactose solution is added to the column and the eluant is assayed using the glucose oxidase assay, available as a kit. We have determined the optimal conditions to give the greatest turnover of lactose while allowing the immobilized enzymes to be active for long periods at room temperature.

  7. Immobilization of whole cells using polymeric coatings

    SciTech Connect

    Lawton, C.W.; Klei, H.E.; Sunstrom, D.V.; Voronka, P.J.; Scott, C.D.

    1986-01-01

    A cell immobilization procedure was developed using latex coatings on solid particles. The method's widespread applicability has been demonstrated by successfully immobilizing Saccharomyces cerevisiae (ethanol production), Bacillus subtilis (tryptophan production). Penicillium chrysogenum (penicillin G production), and Escherichia coli (aspartic acid production). In contrast to other immobilization methods, this procedure produces a pellicular particle that is porous, allowing rapid substrate and gas transfer, has a hard core to avoid compression in large beds, and is dense to allow use in fluidized beds. The immobilization procedure was optimized with S. cerevisiae. Kinetic constants obtained were used to calculate effectiveness factors to show that there was minimal intraparticle diffusion resistance. Reactors utilizing the optimized particles were run for 300 hours to evaluate immobilized particle half-life which was 250 hours.

  8. Immobilization of indigenous holocellulase on iron oxide (Fe2O3) nanoparticles enhanced hydrolysis of alkali pretreated paddy straw.

    PubMed

    Kumar, Ajay; Singh, Surender; Tiwari, Rameshwar; Goel, Renu; Nain, Lata

    2017-03-01

    The holocellulase from Aspergillus niger SH3 was characterized and found to contain 125 proteins including cellulases (26), hemicellulases (21), chitinases (10), esterases (6), amylases (4) and hypothetical protein (32). The crude enzyme was immobilized on five different nanoparticles (NPs) via physical adsorption and covalent coupling methods. The enzyme-nanoparticle complexes (ENC) were screened for protein binding, enzymatic activities and immobilization efficiency. Magnetic enzyme-nanoparticle complexes (MENC) showed higher immobilization efficiency (60-80%) for most of the enzymes. MENC also showed better catalytic efficiencies in term of higher Vmax and lower Km than free enzyme. Saccharification yields from alkali treated paddy straw were higher (375.39mg/gds) for covalently immobilized MENC than free enzyme (339.99mg/gds). The immobilized enzyme was used for two cycles of saccharification with 55% enzyme recovery. Hence, this study for the first time demonstrated the immobilization of indigenous enzyme and its utilization for saccharification of paddy straw.

  9. Recent advances in covalent, site-specific protein immobilization

    PubMed Central

    Meldal, Morten; Schoffelen, Sanne

    2016-01-01

    The properties of biosensors, biomedical implants, and other materials based on immobilized proteins greatly depend on the method employed to couple the protein molecules to their solid support. Covalent, site-specific immobilization strategies are robust and can provide the level of control that is desired in this kind of application. Recent advances include the use of enzymes, such as sortase A, to couple proteins in a site-specific manner to materials such as microbeads, glass, and hydrogels. Also, self-labeling tags such as the SNAP-tag can be employed. Last but not least, chemical approaches based on bioorthogonal reactions, like the azide–alkyne cycloaddition, have proven to be powerful tools. The lack of comparative studies and quantitative analysis of these immobilization methods hampers the selection process of the optimal strategy for a given application. However, besides immobilization efficiency, the freedom in selecting the site of conjugation and the size of the conjugation tag and the researcher’s expertise regarding molecular biology and/or chemical techniques will be determining factors in this regard. PMID:27785356

  10. On-chip immobilization of planarians for in vivo imaging.

    PubMed

    Dexter, Joseph P; Tamme, Mary B; Lind, Christine H; Collins, Eva-Maria S

    2014-09-17

    Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra.

  11. On-chip immobilization of planarians for in vivo imaging

    PubMed Central

    Dexter, Joseph P.; Tamme, Mary B.; Lind, Christine H.; Collins, Eva-Maria S.

    2014-01-01

    Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra. PMID:25227263

  12. Targeted Cell Immobilization by Ultrasound Microbeam

    PubMed Central

    Lee, Jungwoo; Lee, Changyang; Kim, Hyung Ham; Jakob, Anette; Lemor, Robert; Teh, Shia-Yen; Lee, Abraham; Shung, K. Kirk

    2011-01-01

    Various techniques exerting mechanical stress on cells have been developed to investigate cellular responses to externally controlled stimuli. Fundamental mechanotransduction processes, how applied physical forces are converted into biochemical signals, have often been examined by transmitting such forces through cells and probing its pathway at cellular levels. In fact, many cellular biomechanics studies have been performed by trapping (or immobilizing) individual cells, either attached to solid substrates or suspended in liquid media. In that context, we demonstrated two-dimensional acoustic trapping, where a lipid droplet of 125 μm in diameter was directed transversely towards the focus (or the trap center) similar to that of optical tweezers. Under the influence of restoring forces created by a 30 MHz focused ultrasound beam, the trapped droplet behaved as if tethered to the focus by a linear spring. In order to apply this method to cellular manipulation in the Mie regime (cell diameter > wavelength), the availability of sound beams with its beamwidth approaching cell size is crucial. This can only be achieved at a frequency higher than 100 MHz. We define ultrasound beams in the frequency range from 100 MHz to a few GHz as ultrasound microbeams because the lateral beamwidth at the focus would be in the micron range (reviewer #1). Hence a zinc oxide (ZnO) transducer that was designed and fabricated to transmit a 200 MHz focused sound beam was employed to immobilize a 10 μm human leukemia cell (K-562) within the trap. The cell was laterally displaced with respect to the trap center by mechanically translating the transducer over the focal plane. Both lateral displacement and position trajectory of the trapped cell were probed in a two-dimensional space, indicating that the retracting motion of these cells was similar to that of the lipid droplets at 30 MHz. The potential of this tool for studying cellular adhesion between white blood cells and endothelial cells

  13. Ceramic Hosts for Fission Products Immobilization

    SciTech Connect

    Peter C Kong

    2010-07-01

    metal ions, Mg and Ca, in the ceramic host phases. The immobilization of rear earth (lanthanide series) fission products in these ceramic host phases will also be studied this year. Cerium oxide is chosen to represent the rear earth fission product for substitution studies in spinel, perovskite and zirconolite ceramic hosts. Cerium has +3 and +4 oxidation states and it can replace some of the trivalent or tetravalent host ions to produce the substitution ceramics such as MgAl2-xCexO4, CaTi1-xCexO3, CaZr1-xCexTi2O7 and CaZrTi2-xCexO7. X-ray diffraction analysis will be used to compare the crystalline structures of the pure ceramic hosts and the substitution phases. SEM-EDX analysis will be used to study the Ce distribution in the ceramic host phases. The range of cerium doping is planned to reach the full substitution of the trivalent or tetravalent ions, Al, Ti and Zr, in the ceramic host phases.

  14. Plutonium Immobilization Project Baseline Formulation

    SciTech Connect

    Ebbinghaus, B.

    1999-02-01

    A key milestone for the Immobilization Project (AOP Milestone 3.2a) in Fiscal Year 1998 (FY98) is the definition of the baseline composition or formulation for the plutonium ceramic form. The baseline formulation for the plutonium ceramic product must be finalized before the repository- and plant-related process specifications can be determined. The baseline formulation that is currently specified is given in Table 1.1. In addition to the baseline formulation specification, this report provides specifications for two alternative formulations, related compositional specifications (e.g., precursor compositions and mixing recipes), and other preliminary form and process specifications that are linked to the baseline formulation. The preliminary specifications, when finalized, are not expected to vary tremendously from the preliminary values given.

  15. Plutonium Immobilization Can Loading Concepts

    SciTech Connect

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.; Rogers, L.; Fiscus, J.; Dyches, G.

    1998-05-01

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses five can loading conceptual designs and the lists the advantages and disadvantages for each concept. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas. The can loading welder and cutter are very similar to the existing Savannah River Site (SRS) FB-Line bagless transfer welder and cutter and thus they are a low priority development item.

  16. Effect of Sulfonylureas Administered Centrally on the Blood Glucose Level in Immobilization Stress Model

    PubMed Central

    Sharma, Naveen; Sim, Yun-Beom; Park, Soo-Hyun; Lim, Su-Min; Kim, Sung-Su; Jung, Jun-Sub; Hong, Jae-Seung

    2015-01-01

    Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 µg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level. PMID:25954123

  17. Activity of Laccase Immobilized on TiO2-Montmorillonite Complexes

    PubMed Central

    Wang, Qingqing; Peng, Lin; Li, Guohui; Zhang, Ping; Li, Dawei; Huang, Fenglin; Wei, Qufu

    2013-01-01

    The TiO2-montmorillonite (TiO2-MMT) complex was prepared by blending TiO2 sol and MMT with certain ratio, and its properties as an enzyme immobilization support were investigated. The pristine MMT and TiO2-MMT calcined at 800 °C (TiO2-MMT800) were used for comparison to better understand the immobilization mechanism. The structures of the pristine MMT, TiO2-MMT, and TiO2-MMT800 were examined by HR-TEM, XRD and BET. SEM was employed to study different morphologies before and after laccase immobilization. Activity and kinetic parameters of the immobilized laccase were also determined. It was found that the TiO2 nanoparticles were successfully introduced into the MMT layer structure, and this intercalation enlarged the “d value” of two adjacent MMT layers and increased the surface area, while the calcination process led to a complete collapse of the MMT layers. SEM results showed that the clays were well coated with adsorbed enzymes. The study of laccase activity revealed that the optimum pH and temperature were pH = 3 and 60 °C, respectively. In addition, the storage stability for the immobilized laccase was satisfactory. The kinetic properties indicated that laccase immobilized on TiO2-MMT complexes had a good affinity to the substrate. It has been proved that TiO2-MMT complex is a good candidate for enzyme immobilization. PMID:23771020

  18. Antimicrobial Properties of Lysosomal Enzymes Immobilized on NH₂Functionalized Silica-Encapsulated Magnetite Nanoparticles.

    PubMed

    Bang, Seung Hyuck; Sekhon, Simranjeet Singh; Cho, Sung-Jin; Kim, So Jeong; Le, Thai-Hoang; Kim, Pil; Ahn, Ji-Young; Kim, Yang-Hoon; Min, Jiho

    2016-01-01

    The immobilization efficiency, antimicrobial activity and recovery of lysosomal enzymes on NH2 functionalized magnetite nanoparticles have been studied under various conditions. The immobi- lization efficiency depends upon the ratio of the amount of enzyme and magnetite and it shows an increase with magnetite concentration which is due to the presence of amine group at the magnetite surface that leads to a strong attraction. The optimized reaction time to immobilize the lysosomal enzymes on magnetite was determined by using a rolling method. The immobilization efficiency increases with reaction time and reached a plateau after 5 minutes and then remained constant for 10 minutes. However, after 30 minutes the immobilization efficiency decreased to 85%, which is due to the weaker electrostatic interactions between magnetite and detached lysosomal enzymes. The recovery and stability of immobilized lysosomal enzymes has also been studied. The antimicrobial activity was almost 100% but it decreased upon reuse and no activity was observed after its reuse for seven times. The storage stability of lysosomal enzymes as an antimicrobial agent was about 88%, which decreased to 53% after one day and all activity of immobilized lysosomal enzymes was maintained after five days. Thus, the lysosomal enzymes immobilized on magnetite nanoparticles could potentially be used as antimicrobial agents to remove bacteria.

  19. Enzymatic removal of flatulence-inducing sugars in chickpea milk using free and polyvinyl alcohol immobilized alpha-galactosidase from Aspergillus oryzae.

    PubMed

    Patil, Aravind Goud G; Kote, Naganagoud V; Mulimani, Veerappa

    2009-01-01

    The treatment of chickpea milk was carried out in batch, repeated batch and continuous reaction by soluble and polyvinyl alcohol (PVA) immobilized Aspergillus oryzae alpha-galactosidase for the removal of raffinose family oligosaccharides (RFOs). In the batch mode of treatment 96 and 92% of RFOs hydrolysis was observed by soluble and immobilized enzyme, respectively. In repeated batch experiments, immobilized enzyme showed 70% RFOs hydrolysis up to sixth cycle. Polyvinyl alcohol immobilized alpha-galactosidase in fluidized bed reactor showed highest reduction of 94% at a flow rate of 30 ml/h. The results obtained from the present study are very interesting for industrial use of PVA-immobilized enzyme.

  20. Application of Denatured, Electrophoretically Separated, and Immobilized Lysates of Herpes Simplex Virus-Infected Cells for Detection of Monoclonal Antibodies and for Studies of the Properties of Viral Proteins

    PubMed Central

    Braun, Daniel K.; Pereira, Lenore; Norrild, Bodil; Roizman, Bernard

    1983-01-01

    We report the use of herpes simplex virus type 1 (HSV-1)- and HSV-2-infected cell polypeptides (ICPs) separated by electrophoresis in polyacrylamide gels and transferred to nitrocellulose to (i) detect monoclonal antibodies to viral polypeptides and to (ii) study the properties of the proteins with the monoclonal antibodies. Our results were as follows. (i) When the antigens were electrophoretically separated in denaturing gels and then immobilized on nitrocellulose strips, we detected a greater diversity of monoclonal antibodies to viral proteins than when we used the technique of immune precipitation of soluble, nondenatured viral antigens. The primary advantage of the technique is in the detection of nonprecipitating antibody and of antibody to poorly soluble antigens not available for reaction in preparations cleared by high-speed centrifugation before immune reaction. (ii) Studies of the viral polypeptides reactive with three monoclonal antibodies indicated that the technique can be used to investigate several properties of the antigens. Specifically, monoclonal antibody to ICP 4 confirmed the accumulation of viral protein in the nucleus and the mapping of the gene in the S component. The results showed, however, that HSV-1 and HSV-2 ICP 4 do have common antigenic determinants. The reaction of a nonprecipitating monoclonal antibody with electrophoretically separated, immobilized polypeptides contained in cytoplasmic and nuclear fractions, those chemically deglycosylated, or those specified by specific HSV-1 x HSV-2 intertypic recombinants identified the antigens reactive with the second monoclonal antibody as various forms of glycoprotein gC. Of particular interest was a set of four antigens, 39,000 to 46,500 in apparent molecular weight, reactive with each of several monoclonal antibodies. These studies showed that two polypeptides partition in the cytoplasm and two in the nucleus and that all comap with the previously mapped ICPs 35 and 37 in the region of

  1. Application of granular activated carbon/MnFe₂O₄ composite immobilized on C. glutamicum MTCC 2745 to remove As(III) and As(V): Kinetic, mechanistic and thermodynamic studies.

    PubMed

    Podder, M S; Majumder, C B

    2016-01-15

    The main objective of the present study was to investigate the efficiency of Corynebacterium glutamicum MTCC 2745 immobilized on granular activated carbon/MnFe2O4 (GAC/MnFe2O4) composite to treat high concentration of arsenic bearing wastewater. Non-linear regression analysis was done for determining the best-fit kinetic model on the basis of three correlation coefficients and three error functions and also for predicting the parameters involved in kinetic models. The results showed that Fractal-like mixed 1,2 order model for As(III) and Brouser-Weron-Sototlongo as well as Fractal-like pseudo second order models for As(V) were proficient to provide realistic description of biosorption/bioaccumulation kinetic. Applicability of mechanistic models in the current study exhibited that the rate governing step in biosorption/bioaccumulation of both As(III) and As(V) was film diffusion rather than intraparticle diffusion. The evaluated thermodynamic parameters ΔG(0), ΔH(0) and ΔS(0) revealed that biosorption/bioaccumulation of both As(III) and As(V) was feasible, spontaneous and exothermic under studied conditions.

  2. Application of granular activated carbon/MnFe2O4 composite immobilized on C. glutamicum MTCC 2745 to remove As(III) and As(V): Kinetic, mechanistic and thermodynamic studies

    NASA Astrophysics Data System (ADS)

    Podder, M. S.; Majumder, C. B.

    2016-01-01

    The main objective of the present study was to investigate the efficiency of Corynebacterium glutamicum MTCC 2745 immobilized on granular activated carbon/MnFe2O4 (GAC/MnFe2O4) composite to treat high concentration of arsenic bearing wastewater. Non-linear regression analysis was done for determining the best-fit kinetic model on the basis of three correlation coefficients and three error functions and also for predicting the parameters involved in kinetic models. The results showed that Fractal-like mixed 1,2 order model for As(III) and Brouser-Weron-Sototlongo as well as Fractal-like pseudo second order models for As(V) were proficient to provide realistic description of biosorption/bioaccumulation kinetic. Applicability of mechanistic models in the current study exhibited that the rate governing step in biosorption/bioaccumulation of both As(III) and As(V) was film diffusion rather than intraparticle diffusion. The evaluated thermodynamic parameters ΔG0, ΔH0 and ΔS0 revealed that biosorption/bioaccumulation of both As(III) and As(V) was feasible, spontaneous and exothermic under studied conditions.

  3. Immobilization of Lipase from Pseudomonas fluorescens on Porous Polyurea and Its Application in Kinetic Resolution of Racemic 1-Phenylethanol.

    PubMed

    Han, Hui; Zhou, Yamei; Li, Shusheng; Wang, Yinping; Kong, Xiang Zheng

    2016-10-05

    A porous polyurea (PPU) was prepared through a simple protocol by reacting toluene diisocyanate with water in binary solvent of water-acetone. Its amine group was determined through spectrophotometric absorbance based on its iminization with p-nitrobenzaldehyde amines. PPU was then used as a novel polymer support for enzyme immobilization, through activation by glutaraldehyde followed by immobilization of an enzyme, lipase from Pseudomonas fluorescens (PFL), via covalent bonding with the amine groups of lipase molecules. Influences of glutaraldehyde and enzyme concentration and pH in the process were studied. The results revealed that the activity of the immobilized PFL reached a maximum at GA concentration of 0.17 mol/L and at pH 8. Immobilization rate of 60% or higher for PFL was obtained under optimized condition with an enzyme activity of 283 U/mg. The porous structure of PPU, prior to and after GA activation and PFL immobilization, was characterized. The activity of the immobilized PFL at different temperature and pH and its stability at 40 °C as well as its reusability were tested. The immobilized enzyme was finally used as enantioselective catalyst in kinetic resolution of racemic 1-phenylethanol (1-PEOH), and its performance compared with the free PFL. The results demonstrate that the enzyme activity and stability were greatly improved for the immobilized PFL, and highly pure enantiomers from racemic 1-PEOH were effectively achieved using the immobilized PFL. Noticeable deactivation of PFL in the resolution was observed by acetaldehyde in situ formed. In addition, the immobilized PFL was readily recovered from the reaction system for reuse. A total of 73% of the initial activity was retained after 5 repeated reuse cycles. This work provides a novel route to preparation of a polyurea porous material and its enzyme immobilization, leading to a novel type of immobilized enzyme for efficient kinetic resolution of racemic molecules.

  4. Development of a microfluidic "click chip" incorporating an immobilized Cu(I) catalyst.

    PubMed

    Li, Hairong; Whittenberg, Joseph J; Zhou, Haiying; Ranganathan, David; Desai, Amit V; Koziol, Jan; Zeng, Dexing; Kenis, Paul J A; Reichert, David E

    2015-01-01

    We have developed a microfluidic "click chip" incorporating an immobilized Cu(I) catalyst for click reactions. The microfluidic device was fabricated from polydimethylsiloxane (PDMS) bonded to glass and featured ~14,400 posts on the surface to improve catalyst immobilization. This design increased the immobilization efficiency and reduces the reagents' diffusion time to active catalyst site. The device also incorporates five reservoirs to increase the reaction volume with minimal hydrodynamic pressure drop across the device. A novel water-soluble tris-(benzyltriazolylmethyl)amine (TBTA) derivative capable of stabilizing Cu(I), ligand 2, was synthesized and successfully immobilized on the chip surface. The catalyst immobilized chip surface was characterized by X-ray photoelectron spectroscopy (XPS). The immobilization efficiency was evaluated via radiotracer methods: the immobilized Cu(I) was measured as 1136±272 nmol and the surface immobilized Cu(I) density was 81±20 nmol cm(-2). The active Cu(I)-ligand 2 could be regenerated up to five times without losing any catalyst efficiency. The "click" reaction of Flu568-azide and propargylamine was studied on chip for proof-of-principle. The on-chip reaction yields were ca. 82% with a 50 min reaction time or ca. 55% with a 15 min period at 37 °C, which was higher than those obtained in the conventional reaction. The on-chip "click" reaction involving a biomolecule, cyclo(RGDfK) peptide was also studied and demonstrated a conversion yield of ca. 98%. These encouraging results show promise on the application of the Cu(I) catalyst immobilized "click chip" for the development of biomolecule based imaging agents.

  5. Development of a microfluidic “click chip” incorporating an immobilized Cu(I) catalyst

    PubMed Central

    Li, Hairong; Whittenberg, Joseph J.; Zhou, Haiying; Ranganathan, David; Desai, Amit V.; Koziol, Jan; Zeng, Dexing; Kenis, Paul J. A.; Reichert, David E.

    2015-01-01

    We have developed a microfluidic “click chip” incorporating an immobilized Cu(I) catalyst for click reactions. The microfluidic device was fabricated from polydimethylsiloxane (PDMS) bonded to glass and featured ~14,400 posts on the surface to improve catalyst immobilization. This design increased the immobilization efficiency and reduces the reagents’ diffusion time to active catalyst site. The device also incorporates five reservoirs to increase the reaction volume with minimal hydrodynamic pressure drop across the device. A novel water-soluble tris-(benzyltriazolylmethyl)amine (TBTA) derivative capable of stabilizing Cu(I), ligand 2, was synthesized and successfully immobilized on the chip surface. The catalyst immobilized chip surface was characterized by X-ray photoelectron spectroscopy (XPS). The immobilization efficiency was evaluated via radiotracer methods: the immobilized Cu(I) was measured as 1136±272 nmol and the surface immobilized Cu(I) density was 81±20 nmol cm−2. The active Cu(I)-ligand 2 could be regenerated up to five times without losing any catalyst efficiency. The “click” reaction of Flu568-azide and propargylamine was studied on chip for proof-of-principle. The on-chip reaction yields were ca. 82% with a 50 min reaction time or ca. 55% with a 15 min period at 37 °C, which was higher than those obtained in the conventional reaction. The on-chip “click” reaction involving a biomolecule, cyclo(RGDfK) peptide was also studied and demonstrated a conversion yield of ca. 98%. These encouraging results show promise on the application of the Cu(I) catalyst immobilized “click chip” for the development of biomolecule based imaging agents. PMID:25598970

  6. Application of Klebsiella oxytoca immobilized cells on the treatment of cyanide wastewater.

    PubMed

    Chen, C Y; Kao, C M; Chen, S C

    2008-03-01

    Klebsiella oxytoca, isolated from cyanide-containing industrial wastewater, has been shown to be able to biodegrade cyanide to non-toxic end products. The technology of immobilized cells can be applied in biological treatment to enhance the efficiency and effectiveness of biodegradation. In this study, potassium cyanide was used as the target compound and both alginate and cellulose triacetate techniques were applied for the preparation of immobilized cells. Results from this study show that KCN can be utilized as the sole nitrogen source by K. oxytoca. The free suspension systems reveal that the cell viability was highly affected by initial KCN concentration and pH. Results show that immobilized cell systems could tolerate a higher level of KCN concentration and wider ranges of pH. In the batch experiments, the maximum KCN removal efficiencies using alginate and cellulose triacetate immobilized beads were 0.108 and 0.101mM h(-1) at pH 7, respectively. Results also indicate that immobilized system can support a higher biomass concentration. Complete KCN degradation was observed after the operation of four consecutive degradation experiments with the same batch of immobilized cells. This suggests that the activity of immobilized cells can be maintained and KCN can be used as the nitrogen source throughout KCN degradation experiments. The maximum KCN removal rates using alginate and cellulose triacetate immobilized beads in continuous-column system were 0.224 and 0.192mMh(-1) with initial KCN concentration of 3mM, respectively. Results indicate that the immobilized cells of K. oxytoca would be applicable to the treatment of cyanide-containing wastewaters.

  7. Experimental joint immobilization in guinea pigs. Effects on the knee joint

    NASA Technical Reports Server (NTRS)

    Marcondesdesouza, J. P.; Machado, F. F.; Sesso, A.; Valeri, V.

    1980-01-01

    In young and adult guinea pigs, the aftermath experimentally induced by the immobilization of the knee joint in hyperextended forced position was studied. Joint immobilization which varied from one to nine weeks was attained by plaster. Eighty knee joints were examined macro and microscopically. Findings included: (1) muscular hypotrophy and joint stiffness in all animals, directly proportional to the length of immobilization; (2) haemoarthrosis in the first week; (3) intra-articular fibrous tissue proliferation ending up with fibrous ankylosis; (4) hyaline articular cartilage erosions; (5) various degrees of destructive menisci changes. A tentative explanation of the fibrous tissue proliferation and of the cartilage changes is offered.

  8. Immobilization of urease on activated methoxypolyethyleneglycol-5000.

    PubMed

    Hamarat, S; Uslan, A H

    1996-05-01

    Urease (E.C 3.5.1.5) was covalently immobilized on activated methoxypolyethyleneglycol-5000 which is linear, uncharged, soluble in water and nonimmunogenic. mPEG is bound to the epsilon-NH2 groups of Lysin in urease. Previously different molar ratios of urease -Lys/activated-mPEG were searched for immobilization. Storage stabilities, molecular weights and the values of blocked amino groups were determined for each immobilized urease and the best conditions was found 1:3 urease-Lys/activated mPEG. Furthermore physical characterization, kinetic constants (Km, Vmax), heat and temperature stabilites were also determined.

  9. Immobilization of biomolecules on semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Joensson, U.; Malmqvist, M.; Nilsson, H.; Olofsson, G.; Roennberg, I.

    1983-09-01

    A reproducible, stable and functional introduction of reactive groups on oxide covered silicon surfaces used in chemically sensitive field effect transistors and optical methods based on light reflection is described. Biomolecules, such as antibodies, antigens and enzymes, were covalently attached to the surface modified silicon via a thiol disulfide exchange reaction. The immobilization technique eliminates the risk of crosslinking and homopolymerization, giving monolayer coverage in close contact with the surface. The technique was used for immobilized protein A and interaction of such surfaces with immunoglobulins. The result was evaluated by in situ ellipsometry, which gives the amount of immobilized and interacting material on the surfaces.

  10. Plutonium immobilization feed batching system concept report

    SciTech Connect

    Erickson, S.

    2000-07-19

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with high level waste glass for permanent storage. Feed batching is one of the first process steps involved with first stage plutonium immobilization. It will blend plutonium oxide powder before it is combined with other materials to make pucks. This report discusses the Plutonium Immobilization feed batching process preliminary concept, batch splitting concepts, and includes a process block diagram, concept descriptions, a preliminary equipment list, and feed batching development areas.

  11. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    NASA Astrophysics Data System (ADS)

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells.

  12. Corticospinal adaptations and strength maintenance in the immobilized arm following 3 weeks unilateral strength training.

    PubMed

    Pearce, A J; Hendy, A; Bowen, W A; Kidgell, D J

    2013-12-01

    Cross-education strength training has being shown to retain strength and muscle thickness in the immobilized contralateral limb. Corticospinal mechanisms have been proposed to underpin this phenomenon; however, no transcranial magnetic stimulation (TMS) data has yet been presented. This study used TMS to measure corticospinal responses following 3 weeks of unilateral arm training on the contralateral, immobilize arm. Participants (n = 28) were randomly divided into either immobilized strength training (Immob + train) immobilized no training (Immob) or control. Participants in the immobilized groups had their nondominant arm rested in a sling, 15 h/day for 3 weeks. The Immob + train group completed unilateral arm curl strength training, while the Immob and control groups did not undertake training. All participants were tested for corticospinal excitability, strength, and muscle thickness of both arms. Immobilization resulted in a group x time significant reduction in strength, muscle thickness and corticospinal excitability for the untrained limb of the Immob group. Conversely, no significant change in strength, muscle thickness, or corticospinal excitability occurred in the untrained limb of the Immob + train group. These results provide the first evidence of corticospinal mechanisms, assessed by TMS, underpinning the use of unilateral strength training to retain strength and muscle thickness following immobilization of the contralateral limb.

  13. Immobilization of modified papain with anhydride groups on activated cotton fabric.

    PubMed

    Xue, Yong; Nie, Huali; Zhu, Limin; Li, Shubai; Zhang, Haitao

    2010-01-01

    Papain (EC 3.4.22.2) has been chemically modified using two novel reagents including different anhydrides of 1,2,4-benzenetricarboxylic and pyromellitic acids. Then, the modified papain was immobilized on the activated cotton fabric by a two-step method. The number of free amino groups in the modified protein was investigated through the 2,4,6-trinitrobenzenesulfonic acid method. Energy dispersive spectrometer was used to characterize papain immobilization. Some parameters of both modified and native papain immobilized on cotton fabric, such as optimum temperature, optimum pH, and the stabilities for reservation in various detergents were studied and compared. The resultant papain had its optimum pH shifted from 6.0 to 9.0. Compared with immobilized native papain, the thermal stability and the resistance to alkali and washing detergent of immobilized modified enzyme were improved considerably. When the concentration of detergent was 20 mg/ml, the activity of the immobilized pyromellitic papain retained about 40% of its original activity, whereas the native papain was almost inhibited. This work demonstrated that the cotton fabric immobilized modified papain has potential applications in the functional textiles field.

  14. Stereospecificity of mushroom tyrosinase immobilized on a chiral and a nonchiral support.

    PubMed

    Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Canovas, Francisco; García-Ruiz, Pedro Antonio

    2007-05-30

    Mushroom tyrosinase was immobilized from an extract onto glass beads covered with the cross-linked totally cinnamoylated derivates of d-sorbitol (sorbitol cinnamate) and glycerine (glycerine cinnamate). The enzyme was immobilized onto the support by direct adsorption, and the quantity of immobilized tyrosinase was higher for sorbitol cinnamate, the support with the higher number of esterified hydroxyls per unit of monosacharide, than for glycerine cinnamate. The results obtained from the stereospecificity study of the monophenolase and diphenolase activity of immobilized mushroom tyrosinase are reported. The enantiomers L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-alpha-methyldopa, DL-alpha-methyldopa, L-isoprenaline, DL-isoprenaline, L-adrenaline, DL-adrenaline, L-noradrenaline, and D-noradrenaline were assayed with tyrosinase immobilized on a chiral support (sorbitol cinnamate), whereas L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-alpha-methyldopa, and DL-alpha-methyldopa were assayed with tyrosinase immobilized on a nonchiral support (glycerine cinnamate). The same Vmax(app) values for each series of enantiomers were obtained. However, the Km(app) values were different, the l isomers showing lower values than the dl isomers, whereas the highest Km(app) value was obtained with d isomers. No difference was observed in the stereospecificity of tyrosinase immobilized on a chiral (sorbitol cinnamate) or nonchiral (glycerine cinnamate) support.

  15. Stabilization of alpha-chymotrypsin by covalent immobilization on amine-functionalized superparamagnetic nanogel.

    PubMed

    Hong, Jun; Gong, Peijun; Xu, Dongmei; Dong, Li; Yao, Side

    2007-02-20

    Stabilization of alpha-chymotrypsin (CT) by covalent immobilization on the amine-functionalized magnetic nanogel was studied. The amino groups containing superparamagnetic nanogel was obtained by Hoffman degradation of the polyacrylamide (PAM)-coated Fe(3)O(4) nanoparticles prepared by facile photochemical in situ polymerization. CT was then covalently bound to the magnetic nanogel with reactive amino groups by using 1-ethyl-3-(3-dimethylaminepropyl) carbodiimide as coupling reagent. The binding capacity was determined to be 61mg enzyme/g nanogel by BCA protein assay. Specific activity of the immobilized CT was measured to be 0.93U/(mgmin), 59.3% as that of free CT. The obtained immobilized enzyme had better resistance to temperature and pH inactivation in comparison to free enzyme and thus widened the ranges of reaction pH and temperature. The immobilized enzyme exhibited good thermostability, storage stability and reusability. Kinetic parameters were determined for both the immobilized and free enzyme. The value of K(m) of the immobilized enzyme was larger than did the free form, whereas the V(max) was smaller for the immobilized enzyme.

  16. Covalent-bonded immobilization of lipase on poly(phenylene sulfide) dendrimers and their hydrolysis ability.

    PubMed

    Yemul, Omprakash; Imae, Toyoko

    2005-01-01

    Covalent-bonded immobilization of lipase from burkholderia cepacia onto two poly(phenylene sulfide) (PPS) dendrimers with different generations (two and three) was achieved using carbodiimide as a coupling reagent. The hydrolysis activity of olive oil to fatty acid was studied on enzyme-immobilized PPS dendrimers. Enzyme activity was proportional to the enzyme loading, and highest recovered activity was obtained at the medium enzyme loading for both G2 and G3 dendrimers. The immobilization improved the optimum pH and caused the temperature range to widen. Immobilization of enzyme has enhanced the thermal stability of enzyme activity in comparison with free enzyme. The immobilized enzyme as a biocatalyst for batch hydrolysis of olive oil retained 80 approximately 90% activity even after 20 times of recycling. This retention of activity after recycle is very valuable and powerful in enzyme technology. The present noteworthy and vital availability on enzyme reaction of the covalently bonded immobilized lipase on dendrimer came from the structure of dendrimer with a large number of functional terminal groups, which are easily available for immobilization of many lipases at the situation keeping reactive enzymes on the surface of dendrimer.

  17. Endothelial Cell Growth and Differentiation on Collagen-Immobilized Polycaprolactone Nanowire Surfaces.

    PubMed

    Leszczak, Victoria; Baskett, Dominique A; Popat, Ketul C

    2015-06-01

    The success of cardiovascular implants is associated with the development of an endothelium on material surface, critical to the prevention of intimal hyperplasia, calcification and thrombosis. A thorough understanding of the interaction between vascular endothelial cells and the biomaterial involved is essential in order to have a successful application which promotes healing and regeneration through integration with native tissue. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human microvascular endothelial cells (HMVECs). The nanowire surfaces were fabricated from polycaprolactone using a novel nanotemplating technique, and were immobilized with collagen utilizing an aminolysis method. The collagen immobilized nanowire surfaces were characterized using contact angle measurements, scanning electron microscopy and X-ray photoelectron spectroscopy. Human microvascular endothelial cells were used to evaluate the efficacy of the collagen immobilized nanowire surfaces to promote cell adhesion, proliferation, viability and differentiation. The results presented here indicate significantly higher cellular adhesion, proliferation and viability on nanowire and collagen immobilized surfaces as compared to the control surface. Further, HMVECs have a more elongated body and low shape factor on nanostructured surfaces. The differentiation potential of collagen immobilized nanowire surfaces was also evaluated by immunostaining and western blotting for key endothelial cell markers that are expressed when human microvascular endothelial cells are differentiated. Results indicate that expression of VE-cadherin is increased on collagen immobilized surfaces while the expression of von Willebrand factor is statistically similar on all surfaces.

  18. Evaluation of free and immobilized Aspergillus niger NRC1ami pectinase applicable in industrial processes.

    PubMed

    Esawy, Mona A; Gamal, Amira A; Kamel, Zeinat; Ismail, Abdel-Mohsen S; Abdel-Fattah, Ahmed F

    2013-02-15

    The Aspergillus niger NRC1ami pectinase was evaluated according to its hydrolysis efficiency of dry untreated orange peels (UOP), HCl-treated orange peels and NaOH-treated orange peels (HOP and NOP). Pectinase was entrapped in polyvinyl alcohol (PVA) sponge and the optimum pH and temperature of the free and immobilized enzymes were shifted from 4, 40 °C to 6, 50 °C respectively. The study of pH stability of free and immobilized pectinase showed that the immobilization process protected the enzyme strongly from severe alkaline pHs. The immobilization process improved the enzyme thermal stability to great instant. The unique feature of the immobilization process is its ability to solve the orange juice haze problem completely. Immobilized enzyme was reused 12 times in orange juice clarification with 9% activity loss from the original activity. Maximum reaction rate (V(max)) and Michaelis-Menten constant (K(m)) of the partially purified form were significantly changed after immobilization.

  19. Production of xanthan gum by free and immobilized cells of Xanthomonas campestris and Xanthomonas pelargonii.

    PubMed

    Niknezhad, Seyyed Vahid; Asadollahi, Mohammad Ali; Zamani, Akram; Biria, Davoud

    2016-01-01

    Production of xanthan gum using immobilized cells of Xanthomonas campestris and Xanthomonas pelargonii grown on glucose or hydrolyzed starch as carbon sources was investigated. Calcium alginate (CA) and calcium alginate-polyvinyl alcohol-boric acid (CA-PVA) beads were used for the immobilization of cells. Xanthan titers of 8.2 and 9.2g/L were obtained for X. campestris cells immobilized in CA-PVA beads using glucose and hydrolyzed starch, respectively, whereas those for X. pelargonii were 8 and 7.9 g/L, respectively. Immobilized cells in CA-PVA beads were successfully employed in three consecutive cycles for xanthan production without any noticeable degradation of the beads whereas the CA beads were broken after the first cycle. The results of this study suggested that immobilized cells are advantageous over the free cells for xanthan production. Also it was shown that the cells immobilized in CA-PVA beads are more efficient than cells immobilized in CA beads for xanthan production.

  20. Prostaglandin E2 Restores Cancellous Bone to Immobilized Limb and Adds Bone to Overloaded Limb in Right Hindlimb Immobilization Rats

    NASA Technical Reports Server (NTRS)

    Li, M.; Jee, W. S. S.; Ke, H. Z.; Liang, X. G.; Lin, B. Y.; Ma, Y. F.; Setterberg, R. B.

    1993-01-01

    The purpose of this study was to determine whether prostaglandin E2 (PGE2) can restore cancellous bone mass and architecture to osteopenic, continuously immobilized (IM), proximal tibial metaphysis (PTM) in female rats. The right hindlimb of three and one-half-month-old Sprague-Dawley female rats were immobilized by right hindlimb immobilization (RHLI) in which the right hindlimb was underloaded and the contralateral left limb was overloaded during ambulation. After 4 or 12 weeks of RHLI, the rats were treated with 3 or 6 mg PGE2/kg/day and RHLI for 8 or 16 weeks. Bone histomorphometry was performed on microradiographs of PTM. Immobilization (IM) induced a transient cancellous bone loss and decreased trabecular thickness, number and node density, and increased free end density that established a new steady state after 4 weeks of IM. Three or 6 mg PGE2/kg/d for 8 weeks beginning at 4 or 12 weeks of IM completely restored cancellous bone mass (+127 to +188 percent) and structure to the age-related control levels in spite of continuous IM. Another 8 weeks of treatment maintained bone mass and architecture at these levels. No differences in cancellous bone mass and architecture were found between the overloaded PTM or RHLI rats and the age-related controls. However, 3 and 6 mg/kg/d of PGE2 treatment started at 4 or 12 weeks for 8 weeks significantly increased cancellous bone mass in the overloaded PTM (+45 to +74% of untreated controls), and another 8 weeks of treatment maintained bone mass at these levels. Our findings indicate that daily 3 or 6 mg PGE2/kg/d treatment restores and maintains PTM cancellous bone mass in continuously immobilized (right) tibiae, and adds and maintains extra bone to slightly overloaded PTM cancellous bone in female rats.

  1. Novel functionalized fluorescent polymeric nanoparticles for immobilization of biomolecules

    NASA Astrophysics Data System (ADS)

    Jain, Swati; Chattopadhyay, Sruti; Jackeray, Richa; Abid, C. K. V. Zainul; Singh, Harpal

    2013-07-01

    Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable, monodisperse, spherical nano sized particles exhibiting high luminescence properties. Particles with 1% SLS (S1) showed good dispersion stability and fluorescence intensity and were chosen as ideal candidates for further immobilization studies. Steady state fluorescence studies showed 10 times higher fluorescence intensity of S1 nanoparticles than that of pyrene solution in solvent-toluene at the same concentration. Environmental factors such as pH, ionic strength and time were found to have no effect on fluorescence intensity of FPNPs. Surface β-di-ketone groups were utilized for the covalent immobilization of enzyme conjugated antibodies without any activation or pre-treatment of nanoparticles.Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable

  2. Simultaneous and sequential co-immobilization of glucose oxidase and catalase onto florisil.

    PubMed

    Ozyilmaz, Gul; Tukel, S Seyhan

    2007-06-01

    The co-immobilization of Aspergillus niger glucose oxidase (GOD) with bovine liver catalase (CAT) onto florisil (magnesium silicate-based porous carrier) was investigated to improve the catalytic efficiency of GOD against H2O2 inactivation. The effect of the amount of bound CAT on the GOD activity was also studied for 12 different initial combinations of GOD and CAT, using simultaneous and sequential coupling. The sequentially co-immobilized GOD-CAT showed a higher efficiency than the simultaneously co-immobilized GOD-CAT in terms of the GOD activity and economic costs. The highest activity was shown by the sequentially co-immobilized GOD-CAT when the initial amounts of GOD and CAT were 10 mg and 5 mg per gram of carrier. The optimum pH, buffer concentration, and temperature for GOD activity for the same co-immobilized GOD-CAT sample were then determined as pH 6.5, 50 mM, and 30 degrees C, respectively. When compared with the individually immobilized GOD, the catalytic activity of the co-immobilized GOD-CAT was 70% higher, plus the reusability was more than two-fold. The storage stability of the co-immobilized GOD-CAT was also found to be higher than that of the free form at both 5 degrees C and 25 degrees C. The increased GOD activity and reusability resulting from the co-immobilization process may have been due to CAT protecting GOD from inactivation by H2O2 and supplying additional O2 to the reaction system.

  3. Pigeonpea (Cajanus cajan L.) urease immobilized on glutaraldehyde-activated chitosan beads and its analytical applications.

    PubMed

    Kayastha, A M; Srivastava, P K

    2001-01-01

    Urease from pigeonpea (Cajanus cajan L.) was covalently linked to crab shell chitosan beads using glutaraldehyde. The optimum immobilization (64% activity) was observed at 4 degrees C, with a protein concentration of 0.24 mg/bead and 3% glutaraldehyde. The immobilized enzyme stored in 0.05 M Tris-acetate buffer, pH 7.3, at 4 degrees C had a t(1/2) of 110 d. There was practically no leaching of enzyme (<3%) from the immobilized beads in 30 d. The immobilized urease was used 10 times at an interval of 24 h between each use with 80% residual activity at the end of the period. The chitosan-immobilized urease showed a significantly higher Michaelis constant (8.3 mM) compared to that of the soluble urease (3.0 mM). Its apparent optimum pH also shifted from 7.3 to 8.5. Immobilized urease showed an optimal temperature of 77 degrees C, compared with 47 degrees C for the soluble urease. Time-dependent kinetics of the thermal denaturation of immobilized urease was studied and found to be monophasic in nature compared to biphasic in nature for soluble enzyme. This immobilized urease was used to analyze blood urea of some of the clinical samples from the clinical pathology laboratories. The results compared favorably with those obtained by the various chemical/biochemical methods employed in the clinical pathology laboratories. A column packed with immobilized urease beads was also prepared in a syringe for the regular and continuous monitoring of serum urea concentrations.

  4. Immobilization of laccase on SiO₂ nanocarriers improves its stability and reusability.

    PubMed

    Patel, Sanjay K S; Kalia, Vipin C; Choi, Joon-Ho; Haw, Jung-Rim; Kim, In-Won; Lee, Jung Kul

    2014-05-01

    Laccases have a broad range of industrial applications. In this study, we immobilized laccase on SiO2 nanoparticles to overcome problems associated with stability and reusability of the free enzyme. Among different reagents used to functionally activate the nanoparticles, glutaraldehyde was found to be the most effective for immobilization. Optimization of the immobilization pH, temperature, enzyme loading, and incubation period led to a maximum immobilization yield of 75.8% and an immobilization efficiency of 92.9%. The optimum pH and temperature for immobilized laccase were 3.5 and 45°C, respectively, which differed from the values of pH 3.0 and 40°C obtained for the free enzyme. Immobilized laccase retained high residual activities over a broad range of pH and temperature. The kinetic parameter Vmax was slightly reduced from 1,890 to 1,630 μmol/min/mg protein, and Km was increased from 29.3 to 45.6. The thermal stability of immobilized laccase was significantly higher than that of the free enzyme, with a half-life 11- and 18-fold higher at temperatures of 50°C and 60°C, respectively. In addition, residual activity was 82.6% after 10 cycles of use. Thus, laccase immobilized on SiO2 nanoparticles functionally activated with glutaraldehyde has broad pH and temperature ranges, thermostability, and high reusability compared with the free enzyme. It constitutes a notably efficient system for biotechnological applications.

  5. Nitrogenase activity of immobilized Azotobacter vinelandii.

    PubMed

    Seyhan, E; Kirwan, D J

    1979-02-01

    As part of a program to investigate the use of biological nitrogen fixation for fertilizer ammonia production, an investigation into the immobilization of the aerobic, nitrogen-fixing bacterium, Azotobacter vinelandii was undertaken. Immobilization was acaccomplished by adsorption onto an anionic exchange cellulose (Cellex E) with loadings as high as 10'' cells/g resin. Immobilized cell preparations were tested under both batch and continuous-flow conditions. Nitrogenase activities as high as 4200 nmol/min g resin were observed as measured by the acetylene reduction assay. Immobilized cells retained their activity for as long as 117 hr in a continuous-flow reactor. Activity loss appeared to be related to the development of a variant strain.

  6. Immobilization of Rocky Flats Graphite Fines Residue

    SciTech Connect

    Rudisill, T.S.

    1999-04-06

    The development of the immobilization process for graphite fines has proceeded through a series of experimental programs. The experimental procedures and results from each series of experiments are discussed in this report.

  7. Enzyme immobilization on reactive polymer films.

    PubMed

    Cordeiro, Ana L; Pompe, Tilo; Salchert, Katrin; Werner, Carsten

    2011-01-01

    Immobilized enzymes are currently used in many bioanalytical and biomedical applications. This protocol describes the use of thin films of maleic anhydride copolymers to covalently attach enzymes directly to solid supports at defined concentrations. The concentration and activity of the surface-bound enzymes can be tuned over a wide range by adjusting the concentration of enzyme used for immobilization and the physicochemical properties of the polymer platform, as demonstrated here for the proteolytic enzyme Subtilisin A. The versatile method presented allows for the immobilization of biomolecules containing primary amino groups to a broad variety of solid carriers, ranging from silicon oxide surfaces to standard polystyrene well plates and metallic surfaces. The approach can be used to investigate the effects of immobilized enzymes on cell adhesion, and on the catalysis of specific reactions.

  8. Silica-Immobilized Enzyme Reactors (Postprint)

    DTIC Science & Technology

    2007-09-01

    mode of action of drugs such as aspirin and ibuprofen .[61] Serotonin reuptake inhibitors and monoamine oxidase inhibitors can function as...immobilizing PGA onto chromatography supports and using the enantiomeric selectivity of the enzyme to resolve racemic mixtures.[100] Immobilization onto...column. J. Chroma- togr. B. Biomed. Sci. Appl. 2001, 753, 375–383. 37. Jadaud, P.; Wainer, I.W. The stereochemical resolution of the enantiomers of

  9. Immobilization Technologies in Probiotic Food Production

    PubMed Central

    Mitropoulou, Gregoria; Nedovic, Viktor; Goyal, Arun; Kourkoutas, Yiannis

    2013-01-01

    Various supports and immobilization/encapsulation techniques have been proposed and tested for application in functional food production. In the present review, the use of probiotic microorganisms for the production of novel foods is discussed, while the benefits and criteria of using probiotic cultures are analyzed. Subsequently, immobilization/encapsulation applications in the food industry aiming at the prolongation of cell viability are described together with an evaluation of their potential future impact, which is also highlighted and assessed. PMID:24288597

  10. Immobilization technologies in probiotic food production.

    PubMed

    Mitropoulou, Gregoria; Nedovic, Viktor; Goyal, Arun; Kourkoutas, Yiannis

    2013-01-01

    Various supports and immobilization/encapsulation techniques have been proposed and tested for application in functional food production. In the present review, the use of probiotic microorganisms for the production of novel foods is discussed, while the benefits and criteria of using probiotic cultures are analyzed. Subsequently, immobilization/encapsulation applications in the food industry aiming at the prolongation of cell viability are described together with an evaluation of their potential future impact, which is also highlighted and assessed.

  11. Histological and compositional responses of bone to immobilization and other experimental conditions

    NASA Technical Reports Server (NTRS)

    Brown, R. J.; Niklowitz, W. J.

    1985-01-01

    Histological techniques were utilized for evaluating progressive changes in tibial compact bone in adult male monkeys during chronic studies of immobilization-associated osteopenia. The animals were restrained in a semirecumbent position which reduces normally occurring stresses in the lower extremities and results in bone mass loss. The longest immobilization studies were of seven months duration. Losses of haversian bone tended to occur predominatly in the proximal tibia and were characterized by increased activation with excessive depth of penetration of osteoclastic activity. There was no apparent regulation of the size and orientation of resorption cavities. Rapid bone loss seen during 10 weeks of immobilization appeared to be due to unrestrained osteoclastic activity without controls and regulation which are characteristic of adaptive systems. The general pattern of loss persisted throughout 7 months of immobilization. Clear cut evidence of a formation phase in haversian bone was seen only after two months of reambulation.

  12. Herbaceous plants as filters: immobilization of particulates along urban street corridors.

    PubMed

    Weber, Frauke; Kowarik, Ingo; Säumel, Ina

    2014-03-01

    Among air pollutants, particulate matter (PM) is considered to be the most serious threat to human health. Plants provide ecosystem services in urban areas, including reducing levels of PM by providing a surface for deposition and immobilization. While previous studies have mostly addressed woody species, we focus on herbaceous roadside vegetation and assess the role of species traits such as leaf surface roughness or hairiness for the immobilization of PM. We found that PM deposition patterns on plant surfaces reflect site-specific traffic densities and that strong differences in particulate deposition are present among species. The amount of immobilized PM differed according to particle type and size and was related to specific plant species traits. Our study suggests that herbaceous vegetation immobilizes a significant amount of the air pollutants relevant to human health and that increasing biodiversity of roadside vegetation supports air filtration and thus healthier conditions along street corridors.

  13. Reversible immobilization of BSA on Cu-chelated PAMAM dendrimer modified iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Demir, M.; Şenel, M.; Baykal, A.

    2014-09-01

    In this study, polyamidoamine (PAMAM) dendrimer coated superparamagnetite nanoparticles were synthesized by growing of PAMAM on amino-silane coated iron oxide nanoparticles. The PAMAM modified superparamagnetite nanoparticles were used as reversible protein immobilization host materials. During the reversible immobilization studies the effect of different metal ions such as; Cu+2, Zn+2, Co+2, Ni+2 on immobilization efficiency of BSA were evaluated. The maximum BSA adsorption capacity of the PAMAM-MNP- Cu+2 beads was observed to be 52.84 mg/g (BSA/PAMAM-MNP) at pH 7.0. Various characteristics of immobilized BSA such as; effect of generation, effect of pH, BSA concentration, temperature, salt concentration and reusability of PAMAM-MNP were evaluated.

  14. Development of 170 MHz Electrodeless Quartz-Crystal Microbalance Immunosensor with Nonspecifically Immobilized Receptor Proteins

    NASA Astrophysics Data System (ADS)

    Ogi, Hirotsugu; Nagai, Hironao; Fukunishi, Yuji; Yanagida, Taiji; Hirao, Masahiko; Nishiyama, Masayoshi

    2010-07-01

    Staphylococcus aureus protein A (SPA) shows high nonspecific binding affinity on a naked quartz surface, and it can be used as the receptor protein for detecting immunoglobulin G (IgG), the most important immunoglobulin. The immunosensor ability, however, significantly depends on the immobilization procedure. In this work, the effect of the nonspecific immobilization procedure on the sensor sensitivity is studied using a home-built electrodeless quartz-crystal microbalance (QCM) biosensor. The pure-shear vibration of a 9.7-µm-thick AT-cut quartz plate is excited and detected in liquids by the line antenna located outside the flow channel. SPA molecules are immobilized on the quartz surfaces, and human IgG is injected to monitor the binding reaction between SPA and IgG. This study reveals that a long (nearly 24 h) immersion procedure is required for immobilizing SPA to achieve the tight biding with the quartz surfaces.

  15. Development of 170 MHz Electrodeless Quartz-Crystal Microbalance Immunosensor with Nonspecifically Immobilized Receptor Proteins

    NASA Astrophysics Data System (ADS)

    Hirotsugu Ogi,; Hironao Nagai,; Yuji Fukunishi,; Taiji Yanagida,; Masahiko Hirao,; Masayoshi Nishiyama,

    2010-07-01

    Staphylococcus aureus protein A (SPA) shows high nonspecific binding affinity on a naked quartz surface, and it can be used as the receptor protein for detecting immunoglobulin G (IgG), the most important immunoglobulin. The immunosensor ability, however, significantly depends on the immobilization procedure. In this work, the effect of the nonspecific immobilization procedure on the sensor sensitivity is studied using a home-built electrodeless quartz-crystal microbalance (QCM) biosensor. The pure-shear vibration of a 9.7-μm-thick AT-cut quartz plate is excited and detected in liquids by the line antenna located outside the flow channel. SPA molecules are immobilized on the quartz surfaces, and human IgG is injected to monitor the binding reaction between SPA and IgG. This study reveals that a long (nearly 24 h) immersion procedure is required for immobilizing SPA to achieve the tight biding with the quartz surfaces.

  16. Improved anticoagulation of titanium by sequential immobilization of oligo(ethylene glycol) and 2-methacryloyloxyethyl phosphorylcholine.

    PubMed

    Pan, Chang-Jiang; Hou, Yan-Hua; Liu, Heng-Quan; Ding, Hong-Yan; Dong, Yun-Xiao

    2013-12-01

    Titanium and its alloys have been widely used for blood-contacting biomedical devices; however, their blood compatibility needs to be improved. In this study, titanium surface was modified by sequential immobilization of oligo(ethylene glycol) (OEG) and 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve its anticoagulation. Water contact angle results showed an excellent hydrophilic surface after the immobilization. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) confirmed that OEG and MPC were successfully immobilized on titanium surface. Static platelet adhesion and APTT (activated partial thromboplastin time) experiments suggested that the anticoagulation of titanium was significantly enhanced by the immobilization of OEG and further by subsequent MPC grafting. The approach in the present study opens up a window of promising an effective and efficient method to improve the anticoagulation of blood-contact biomedical devices such as coronary stents.

  17. Cell immobilization on polymer by air atmospheric pressure plasma jet treatment

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Hwan; Kwon, Jae-Sung; Om, Ji-yeon; Kim, Yong-Hee; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-08-01

    The study of cell immobilization on delicate polymer by an air atmospheric pressure plasma jet (AAPPJ) is required for its medical application. The aim of this study was to evaluate whether AAPPJ treatment induce cell immobilization effect on delicate polymers without significant change of surface roughness by AAPPJ treatment. After surface roughness, dynamic contact angle, and chemical characteristics were investigated, the immobilization effect was evaluated with the mouse fibroblast L929 cell line. Surface roughness change was not observed (P > 0.05) in either delicate dental wax or polystyrene plate (PSP) as advancing and receding contact angles significantly decreased (P < 0.05), thanks to decreased hydrocarbon and formation of oxygen-related functional groups in treated PSP. Adherent L929 cells with elongated morphology were found in treated PSP along with the formation of immobilization markers vinculin and actin cytoskeleton. Increased PTK2 gene expression upregulated these markers on treated PSP.

  18. Immobilization of Fast Reactor First Cycle Raffinate

    SciTech Connect

    Langley, K. F.; Partridge, B. A.; Wise, M.

    2003-02-26

    This paper describes the results of work to bring forward the timing for the immobilization of first cycle raffinate from reprocessing fuel from the Dounreay Prototype Fast Reactor (PFR). First cycle raffinate is the liquor which contains > 99% of the fission products separated from spent fuel during reprocessing. Approximately 203 m3 of raffinate from the reprocessing of PFR fuel is held in four tanks at the UKAEA's site at Dounreay, Scotland. Two methods of immobilization of this high level waste (HLW) have been considered: vitrification and cementation. Vitrification is the standard industry practice for the immobilization of first cycle raffinate, and many papers have been presented on this technique elsewhere. However, cementation is potentially feasible for immobilizing first cycle raffinate because the heat output is an order of magnitude lower than typical HLW from commercial reprocessing operations such as that at the Sellafield site in Cumbria, England. In fact, it falls within the upper end of the UK definition of intermediate level waste (ILW). Although the decision on which immobilization technique will be employed has yet to be made, initial development work has been undertaken to identify a suitable cementation formulation using inactive simulant of the raffinate. An approach has been made to the waste disposal company Nirex to consider the disposability of the cemented product material. The paper concentrates on the process development work that is being undertaken on cementation to inform the decision making process for selection of the immobilization method.

  19. Surface cell immobilization within perfluoroalkoxy microchannels

    NASA Astrophysics Data System (ADS)

    Stojkovič, Gorazd; Krivec, Matic; Vesel, Alenka; Marinšek, Marjan; Žnidaršič-Plazl, Polona

    2014-11-01

    Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor® and Topas®.

  20. Immobilization induces a very rapid increase in osteoclast activity

    NASA Astrophysics Data System (ADS)

    Heer, Martina; Baecker, Natalie; Mika, Claudia; Boese, Andrea; Gerzer, Rupert

    2005-07-01

    We studied in a randomized, strictly controlled cross-over design, the effects of 6 days 6° head-down tilt bed rest (HDT) in eight male healthy subjects in our metabolic ward. The study consisted of two periods (phases) of 11 days each in order to allow for the test subjects being their own controls. Both study phases were identical with respect to environmental conditions, study protocol and diet. Two days before arriving in the metabolic ward the subjects started with a diet. The diet was continued in the metabolic ward. The metabolic ward period (1l days) was divided into three parts: 4 ambulatory days, 6 days either HDT or control and 1 recovery day. Continuous urine collection started on the first day in the metabolic ward to analyze calcium excretion and bone resorption markers. On the 2nd ambulatory day in the metabolic ward and on the 5th day in HDT or control blood was drawn to analyze serum calcium, parathyroid hormone, and bone formation markers. Urinary calcium excretion was, as early as the first day in immobilization, increased (p<0.01). CTX- and NTX-excretion stayed unchanged in the first 24 h in HDT compared to the control. But already on the 2nd day of immobilization, both bone resorption markers significantly increased. We conclude from these results—pronounced rise of bone resorption markers—that already 24 h of immobilization induce a significant rise in osteoclast activity in healthy subjects. Thus, it appears possible to use short-term bed rest studies as a first step for the development of countermeasures to immobilization.

  1. Ceramification: A plutonium immobilization process

    SciTech Connect

    Rask, W.C.; Phillips, A.G.

    1996-05-01

    This paper describes a low temperature technique for stabilizing and immobilizing actinide compounds using a combination process/storage vessel of stainless steel, in which measured amounts of actinide nitrate solutions and actinide oxides (and/or residues) are systematically treated to yield a solid article. The chemical ceramic process is based on a coating technology that produces rare earth oxide coatings for defense applications involving plutonium. The final product of this application is a solid, coherent actinide oxide with process-generated encapsulation that has long-term environmental stability. Actinide compounds can be stabilized as pure materials for ease of re-use or as intimate mixtures with additives such as rare earth oxides to increase their degree of proliferation resistance. Starting materials for the process can include nitrate solutions, powders, aggregates, sludges, incinerator ashes, and others. Agents such as cerium oxide or zirconium oxide may be added as powders or precursors to enhance the properties of the resulting solid product. Additives may be included to produce a final product suitable for use in nuclear fuel pellet production. The process is simple and reduces the time and expense for stabilizing plutonium compounds. It requires a very low equipment expenditure and can be readily implemented into existing gloveboxes. The process is easily conducted with less associated risk than proposed alternative technologies.

  2. Nanoscale dielectrophoretic spectroscopy of individual immobilized mammalian blood cells.

    PubMed

    Lynch, Brian P; Hilton, Al M; Simpson, Garth J

    2006-10-01

    Dielectrophoretic force microscopy (DEPFM) and spectroscopy have been performed on individual intact surface-immobilized mammalian red blood cells. Dielectrophoretic force spectra were obtained in situ in approximately 125 ms and could be acquired over a region comparable in dimension to the effective diameter of a scanning probe microscopy tip. Good agreement was observed between the measured dielectrophoretic spectra and predictions using a single-shell cell model. In addition to allowing for highly localized dielectric characterization, DEPFM provided a simple means for noncontact imaging of mammalian blood cells under aqueous conditions. These studies demonstrate the feasibility of using DEPFM to monitor localized changes in membrane capacitance in real time with high spatial resolution on immobilized cells, complementing previous studies of mobile whole cells and cell suspensions.

  3. The interaction of bioactive peptides with an immobilized phosphatidylcholine monolayer.

    PubMed Central

    Mozsolits, H; Lee, T H; Wirth, H J; Perlmutter, P; Aguilar, M I

    1999-01-01

    The interaction of three bioactive peptides, bombesin, beta-endorphin, and glucagon with a phosphatidylcholine monolayer that was immobilized to porous silica particles and packed into a stainless steel column cartridge, has been studied using dynamic elution techniques. This immobilized lipid monolayer provides a biophysical model system with which to study the binding of peptides to a lipid membrane. In particular, the influence of temperature and methanol concentration on the affinity of each peptide for the immobilized lipid surface was assessed. For all test peptides, nonlinear retention plots were observed at all temperatures that contrasted sharply with the simple linear plots observed for the small unstructured control molecules N-acetyltryptophanamide and diphenylalanine. An analysis of the thermodynamics of the interaction of peptides with the immobilized monolayer was also carried out. The results revealed that while the peptides interacted with the monolayer predominantly through hydrophobic interactions, the relative contribution of DeltaH(assoc)(O) and DeltaS(assoc)(O) to the overall free energy of association was dependent on the temperature and methanol concentration. In particular, it was evident that under most conditions, the binding of the peptides to the immobilized lipid monolayer was enthalpy-driven, i.e., mediated by nonclassical hydrophobic interactions. Significant band-broadening and asymmetric and split peaks were also observed for bombesin, beta-endorphin, and glucagon at different temperatures and methanol concentrations. These changes in affinity and peak shape are consistent with the formation of multiple conformational species during the interaction of these peptides with the lipid monolayer. In addition, the binding behavior of the three test peptides on an n-octylsilica surface that lacked the phospho headgroups of the phospholipid was significantly different from that observed with the immobilized phosphatidylcholine surface

  4. Calmodulin-mediated reversible immobilization of enzymes.

    PubMed

    Daunert, Sylvia; Bachas, Leonidas G; Schauer-Vukasinovic, Vesna; Gregory, Kalvin J; Schrift, G; Deo, Sapna

    2007-07-01

    This work demonstrates the use of the protein calmodulin, CaM, as an affinity tag for the reversible immobilization of enzymes on surfaces. Our strategy takes advantage of the of the reversible, calcium-mediated binding of CaM to its ligand phenothiazine and of the ability to produce fusion proteins between CaM and a variety of enzymes to reversibly immobilize enzymes in an oriented fashion to different surfaces. Specifically, we employed two different enzymes, organophosphorus hydrolase (OPH) and beta-lactamase and two different solid supports, a silica surface and cellulose membrane modified by covalently attaching a phenothiazine ligand, to demonstrate the versatility of our immobilization method. Fusion proteins between CaM-OPH and CaM-beta-lactamase were prepared by using genetic engineering strategies to introduce the calmodulin tail at the N-terminus of each of the two enzymes. In the presence of Ca(2+), CaM adopts a conformation that favors interaction between hydrophobic pockets in CaM and phenothiazine, while in the presence of a Ca(2+)-chelating agent such as EGTA, the interaction between CaM and phenothiazine is disrupted, thus allowing for removal of the CaM-fusion protein from the surface under mild conditions. CaM also acts as a spacer molecule, orienting the enzyme away from the surface and toward the solution, which minimizes enzyme interactions with the immobilization surface. Since the method is based on the highly selective binding of CaM to its phenothiazine ligand, and this is covalently immobilized on the surface, the method does not suffer from ligand leaching nor from interference from other proteins present in the cell extract. An additional advantage lies in that the support can be regenerated by passing through EGTA, and then reused for the immobilization of the same or, if desired, a different enzyme. Using a fusion protein approach for immobilization purposes avoids the use of harsh conditions in the immobilization and/or regeneration

  5. Biomolecular Stress-Sensitive Gauges: Surface-Mediated Immobilization of Mechanosensitive Membrane Protein

    DTIC Science & Technology

    2003-01-01

    Immobilization of Mechanosensitive Membrane Protein 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER...8-98) Prescribed by ANSI Std Z39-18 Biomolecular Stress-Sensitive Gauges: Surface-Mediated Immobilization of Mechanosensitive Membrane Protein...biomolecular gauges.1 Studies of a mechanosensitive protein of large conductance (MscL) had shown that a dramatic change in the protein conformation

  6. [Immobilization and skeletal system of the human body].

    PubMed

    Kisała, Aleksander; Pluskiewicz, Wojciech

    2015-01-01

    Shaping the process of evolution musculoskeletal and nervous systems in animals has allowed these organisms steady increase mobility and mastery of new environments to life. Movement is the essence of life and health. But health is not a permanent condition. Its absence often results in limited mobility of the body. The aim of this study is to assess the impact of immobilization on the state of the skeletal system and the evaluation of the effectiveness of various measures to reduce this impact.

  7. Catechol Removal from Aqueous Media Using Laccase Immobilized in Different Macro- and Microreactor Systems.

    PubMed

    Tušek, Ana Jurinjak; Šalić, Anita; Zelić, Bruno

    2017-01-23

    Laccase belongs to the group of enzymes that are capable to catalyze the oxidation of phenols. Since the water is only by-product in laccase-catalyzed phenol oxidations, it is ideally "green" enzyme with many possible applications in different industrial processes. To make the oxidation process more sustainable in terms of biocatalyst consumption, immobilization of the enzyme is implemented in to the processes. Additionally, when developing a process, choice of a reactor type plays a significant role in the total outcome.In this study, the use of immobilized laccase from Trametes versicolor for biocatalytic catechol oxidation was explored. Two different methods of immobilization were performed and compared using five different reactor types. In order to compare different systems used for catechol oxidation, biocatalyst turnover number and turnover frequency were calculated. With low consumption of the enzyme and good efficiency, obtained results go in favor of microreactors with enzyme covalently immobilized on the microchannel surface.

  8. Laboratory assessment of bioleaching of shallow eutrophic sediment by immobilized photosynthetic bacteria.

    PubMed

    Sun, Shiyong; Fan, Shenglan; Shen, Kexuan; Lin, Shen; Nie, Xiaoqin; Liu, Mingxue; Dong, Faqin; Li, Jian

    2016-12-07

    Eutrophic sediment is a serious problem in ecosystem restoration, especially in shallow lake ecosystems. We present a novel bioleaching approach to treat shallow eutrophic sediment with the objective of preventing the release of nitrate, phosphate, and organic compounds from the sediment to the water column, using porous mineral-immobilized photosynthetic bacteria (PSB). Bioactivity of bacteria was maintained during the immobilization process. Immobilized PSB beads were directly deposited on the sediment surface. The deposited PSB utilized pollutants diffused from the sediment as a nutritive matrix for growth. We evaluated the effects of light condition, temperature, initial pH, amount of PSB beads, and frequency of addition of PSB beads for contaminant removal efficiency during bioleaching operations. The presented study indicated that immobilized PSB beads using porous minerals as substrates have considerable application potential in bioremediation of shallow eutrophic lakes.

  9. Decolorization of direct dyes by immobilized turnip peroxidase in batch and continuous processes.

    PubMed

    Matto, Mahreen; Husain, Qayyum

    2009-03-01

    An inexpensive immobilized turnip peroxidase has been employed for the decolorization of some direct dyes in batch and continuous reactors. Wood shaving was investigated as an inexpensive material for the preparation of bioaffinity support. Concanavalin A-wood shaving bound turnip peroxidase exhibited 67% of the original enzyme activity. Both soluble and immobilized turnip peroxidase could effectively remove more than 50% color from dyes in the presence of metals/salt and 0.6mM 1-hydroxybenzotriazole, after 1h of incubation. The columns containing immobilized peroxidase could decolorize 64% direct red 23% and 50% mixture of direct dyes at 4 and 3 months of operation, respectively. Total organic carbon analysis of treated dye or mixture of dyes revealed that these results were quite comparable to the loss of color from solutions. Thus, this study showed that the immobilized enzyme could be efficiently used for the removal of synthetic dyes from industrial effluents.

  10. Laccase immobilized on mesoporous SiO2 and its use for degradation of chlorophenol pesticides

    NASA Astrophysics Data System (ADS)

    Yang, Yuxiang; Xu, Yong; Yang, Yiwen; Yang, Huan; Yuan, Hongmin; Huang, Yan; Liu, Xiangnong

    2016-10-01

    In this paper, mesoporous silica with large specific surface area was used to immobilize laccase by the glutaraldehyde cross-linking method, and after screening and optimization experiments, the best enzyme immobilization process conditions were found (25°C, pH 5.4, 4% glutaraldehyde and 0.2 g/L laccase, treatment time 6 h). After that, the removal and degradation ratio of 2,4-dichlorophenol (abbreviated as DCP) under different conditions were also studied. After the degradation process was performed for 6 h at 30°C, pH 5.4, and DCP initial concentration of 50 mg/L in the presence of 0.1 g of immobilized laccase, the removal ratio and the degradation ratio were 42.28 and 15.93%, respectively. Compared with free laccase, the reusability of immobilized laccase is significantly improved.

  11. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry.

    PubMed

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan

    2016-03-16

    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%.

  12. Denitrification of high nitrate wastewater in a cloth strip bioreactor with immobilized sludge.

    PubMed

    Nair, Rashmi R; D'Souza, Stanislaus F

    2012-11-01

    Denitrification of synthetic high nitrate wastewater containing 40,000 ppm NO(3) (9,032 ppm NO(3)-N) was achieved using immobilized activated sludge in a column reactor. Active anoxic sludge adsorbed onto Terry cloth was used in the denitrification of high nitrate wastewater. The operational stability of the immobilized sludge system was studied both in a batch reactor and in a continuous reactor. The immobilized sludge showed complete degradation of different concentrations of NO(3)-N (1,129, 1,693, 3,387, 6,774, and 9,032 ppm) in a batch process. The reactors were successfully run for 90 days without any loss in activity. The immobilized cell process has yielded promising results in attaining high denitrifying efficiency.

  13. Linear alkyl benzene sulphonate (LAS) degradation by immobilized Pseudomonas aeruginosa under low intensity ultrasound.

    PubMed

    Lijun, Xiang; Bochu, Wang; Zhimin, Li; Chuanren, Duan; Qinghong, Wang; Liu, Liu

    2005-01-15

    We studied the LAS degradation of immobilized Pseudomonas aeruginosa with low-intensity ultrasonic and the influence of original LAS concentration, pH, rotary velocity and different conditions of low-intensity ultrasonic irradiation on the degradation of LAS. In our experiment, the degradation rate of LAS was the main index. We found that low-intensity ultrasonic irradiation could improve the metabolism of microorganism cells and promote the LAS biodegradation of immobilized cells. In the experiment, 50 mg/l LAS were used to simulate wastewater, and low-intensity ultrasonic was considered. We found the influence was obvious, and the optimal degradation rate was acquired when the conditions of ultrasonic were frequency 24 kHz, power 8 W, stimulation time 5 s, intermissive time 30 s, and total time 10 min. The LAS degradation rate of immobilized cells with ultrasonic were respectively 40% and 9.5% higher than that of the suspending cells and immobilized cells without irradiation.

  14. Effect of immobilization stress on the level of macroergic phosphates in the blood of rats

    NASA Technical Reports Server (NTRS)

    Pudov, V. I.; Sosenkov, V. A.

    1980-01-01

    The effect of immobilization for 1, 2, and 24 hours, and of daily (for 2 hours for 7 days) immobilization on the blood nucleotide (ATP, ADP, AMP) level was studied on 79 male rats. A progressive reduction of the ATP content was most pronounced in immobilization for 24 hours. This was accompanied by an increase of lymphopenia and eosinopenia. A fall of the relative weight of the thymus and a weight gain of the adrenal glands was observed along with a reduction of ascorbic acid concentration in both of them. In case of daily immobilization for 2 hours, the ATP and ADP content on the 1st and 2nd day was below the normal level, and then showed a gradual increase, with complete normalization in 6-7 days, except for inorganic phosphorus the level of which remained lower than normal.

  15. [Optimization of the conditions of immobilization of enzymes in a photopolymeric membrane].

    PubMed

    Rebriev, A V; Starodub, N F; Masliuk, A F

    2002-01-01

    The residual activity of enzymes immobilized in the membrane on the basis on 1-vinyl-2-pyrrolidinone as photopolymerizable composition is studied. It is established, that under conditions of the immobilization at 20 degrees C the residual activity glucoseoxidase is about 35% from a initial level, horseredish peroxidase and urease from Jeack beans--42% and 20%, respectively. In case of an immobilization of beta-glucoseoxidase -50 degrees C it reaches almost 50% from a initial level. It was investigated the influence of different sources of UV-radiation and different substances on stability of the enzymes in the composition and in the immobilization matrix at storage. Dynamic of changes of enzyme activity at the photoimmobilization was characterized, and also the requirements for providing of its maximal storage was selected.

  16. Characterization of immobilization methods of antiviral antibodies in serum for electrochemical biosensors

    NASA Astrophysics Data System (ADS)

    Huy, Tran Quang; Hanh, Nguyen Thi Hong; Van Chung, Pham; Anh, Dang Duc; Nga, Phan Thi; Tuan, Mai Anh

    2011-06-01

    In this paper, we describes different methods to immobilize Japanese encephalitis virus (JEV) antibodies in human serum onto the interdigitated surface of a microelectrode sensor for optimizing electrochemical detection: (1) direct covalent binding to the silanized surface, (2) binding to the silanized surface via a cross-linker of glutaraldehyde (GA), (3) binding to glutaraldehyde/silanized surface via goat anti-human IgG polyclonal antibody and (4) binding to glutaraldehyde/silanized surface via protein A (PrA). Field emission scanning electron microscopy, Fourier transform infrared spectrometry, and fluorescence microscopy are used to verify the characteristics of antibodies on the interdigitated surface after the serum antibodies immobilization. The analyzed results indicate that the use of protein A is an effective choice for immobilization and orientation of antibodies in serum for electrochemical biosensors. This study provides an advantageous immobilization method of serum containing antiviral antibodies to develop electrochemical biosensors for preliminary screening of viruses in clinical samples from outbreaks.

  17. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry

    PubMed Central

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P.; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan

    2016-01-01

    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%. PMID:26999137

  18. Immobilization of a Pleurotus ostreatus Laccase Mixture on Perlite and Its Application to Dye Decolourisation

    PubMed Central

    Salatino, Piero; Sannia, Giovanni

    2014-01-01

    In the present study, a crude laccase preparation from Pleurotus ostreatus was successfully immobilized on perlite, a cheap porous silica material, and tested for Remazol Brilliant Blue R (RBBR) decolourisation in a fluidized bed recycle reactor. Results showed that RBBR decolourisation is mainly due to enzyme action despite the occurrence of dye adsorption-related enzyme inhibition. Fine tuning of immobilization conditions allowed balancing the immobilization yield and the resulting rate of decolourisation, with the adsorption capacity of the solid biocatalyst. In the continuous lab scale reactor, a maximum conversion degree of 56.1% was achieved at reactor space-time of 4.2 h. Stability and catalytic parameters of the immobilized laccases were also assessed in comparison with the soluble counterparts, revealing an increase in stability, despite a reduction of the catalytic performances. Both effects are most likely ascribable to the occurrence of multipoint attachment phenomena. PMID:24895564

  19. Covalent immobilization of protein onto a functionalized hydrogenated diamond-like carbon substrate.

    PubMed

    Biswas, Hari Shankar; Datta, Jagannath; Chowdhury, D P; Reddy, A V R; Ghosh, Uday Chand; Srivastava, Arvind Kumar; Ray, Nihar Ranjan

    2010-11-16

    Hydrogenated diamond-like carbon (HDLC) has an atomically smooth surface that can be deposited on high-surface area substrata and functionalized with reactive chemical groups, providing an ideal substrate for protein immobilization. A synthetic sequence is described involving deposition and hydrogenation of DLC followed by chemical functionalization. These functional groups are reacted with amines on proteins causing covalent immobilization on contact. Raman measurements confirm the presence of these surface functional groups, and Fourier transform infrared spectroscopy (FTIR) confirms covalent protein immobilization. Atomic force microscopy (AFM) of immobilized proteins is reproducible because proteins do not move as a result of interactions with the AFM probe-tip, thus providing an advantage over mica substrata typically used in AFM studies of protein. HDLC offers many of the same technical advantages as oxidized graphene but also allows for coating large surface areas of biomaterials relevant to the fabrication of medical/biosensor devices.

  20. STM characterization of DNA immobilized via Zr ion glue onto gold thiol SAMs

    NASA Astrophysics Data System (ADS)

    Pourbeyram, S.; Shervedani, R. K.; Sabzyan, H.

    2013-10-01

    In this paper layer-by-layer (LBL) assembly of calf thymus DNA (ct-DNA) onto gold-mercaptopropionic acid self-assembled monolayer via Zr(IV) ion glue, Au-MPA-Zr(IV)-ct-DNA SAM, is monitored by scanning tunneling microscopy (STM) technique. The STM images of Au-MPA-Zr(IV) template show well-organized arrays of rod-like peaks. ct-DNA has been immobilized on the Au-MPA-Zr(IV) surface in hilly forms, implying globular structure for the immobilized ct-DNA. This immobilization strategy offers a simple and fast method to prepare the Au-MPA-Zr(IV)-ct-DNA template with promising applications for immobilization and study of the other compounds.

  1. Assessment of the Behavior of Mesenchymal Stem Cells Immobilized in Biomimetic Alginate Microcapsules.

    PubMed

    Garate, Ane; Ciriza, Jesús; Casado, Javier G; Blazquez, Rebeca; Pedraz, José Luis; Orive, Gorka; Hernandez, Rosa Maria

    2015-11-02

    The combination of mesenchymal stem cells (MSCs) and biomimetic matrices for cell-based therapies has led to enormous advances, including the field of cell microencapsulation technology. In the present work, we have evaluated the potential of genetically modified MSCs from mice bone marrow, D1-MSCs, immobilized in alginate microcapsules with different RGD (Arg-Gly-Asp) densities. Results demonstrated that the microcapsules represent a suitable platform for D1-MSC encapsulation since cell immobilization into alginate matrices does not affect their main characteristics. The in vitro study showed a higher activity of D1-MSCs when they are immobilized in RGD-modified alginate microcapsules, obtaining the highest therapeutic factor secretion with low and intermediate densities of the bioactive molecule. In addition, the inclusion of RGD increased the differentiation potential of immobilized cells upon specific induction. However, subcutaneous implantation did not induce differentiation of D1-MSCs toward any lineage remaining at an undifferentiated state in vivo.

  2. Immobilization of a Pleurotus ostreatus laccase mixture on perlite and its application to dye decolourisation.

    PubMed

    Pezzella, Cinzia; Russo, Maria Elena; Marzocchella, Antonio; Salatino, Piero; Sannia, Giovanni

    2014-01-01

    In the present study, a crude laccase preparation from Pleurotus ostreatus was successfully immobilized on perlite, a cheap porous silica material, and tested for Remazol Brilliant Blue R (RBBR) decolourisation in a fluidized bed recycle reactor. Results showed that RBBR decolourisation is mainly due to enzyme action despite the occurrence of dye adsorption-related enzyme inhibition. Fine tuning of immobilization conditions allowed balancing the immobilization yield and the resulting rate of decolourisation, with the adsorption capacity of the solid biocatalyst. In the continuous lab scale reactor, a maximum conversion degree of 56.1% was achieved at reactor space-time of 4.2 h. Stability and catalytic parameters of the immobilized laccases were also assessed in comparison with the soluble counterparts, revealing an increase in stability, despite a reduction of the catalytic performances. Both effects are most likely ascribable to the occurrence of multipoint attachment phenomena.

  3. Kinetic analysis of dihydroxyacetone production from crude glycerol by immobilized cells of Gluconobacter oxydans MTCC 904.

    PubMed

    Dikshit, Pritam Kumar; Moholkar, Vijayanand S

    2016-09-01

    The present study has investigated kinetic features of bioconversion of biodiesel-derived crude glycerol to dihydroxyacetone with immobilized Gluconobacter oxydans cells using modified Haldane substrate-inhibition model. The results have been compared against free cells and pure glycerol. Relative variations in the kinetic parameters KS, KI, Vmax, n and X reveal that immobilized G. oxydans cells (on PU foam substrate) with crude glycerol as substrate give higher order of inhibition (n) and lower maximum reaction velocities (Vmax). These results are essentially implications of substrate transport restrictions across immobilization matrix, which causes retention of substrate in the matrix and reduction in fractional available substrate (X) for the cells. This causes reduction in both KS (substrate concentration at Vmax/2) and KI (inhibition constant) as compared to free cells. For immobilized cells, substrate concentration (Smax) corresponding to Vmax is practically same for both pure and crude glycerol as substrate.

  4. Water equivalent thickness analysis of immobilization devices for clinical implementation in proton therapy.

    PubMed

    Wroe, A J; Ghebremedhin, A; Gordon, I R; Schulte, R W; Slater, J D

    2014-10-01

    Immobilization devices can impact not only the inter- and intra-fraction motion of the patient, but also the range uncertainty of the treatment beam in proton therapy. In order to limit additional range uncertainty, the water equivalent thickness (WET) of the immobilization device needs to be well known and accurately reflected in the calculations by the treatment planning system (TPS). The method presented here focusses on the use of a nozzle-mounted variable range shifter and precision-machined polystyrene blocks of known WET to evaluate commercial immobilization devices prior to clinical implementation. CT studies were also completed to evaluate the internal uniformity of the immobilization devices under study. Mul- tiple inserts of the kVue platform (Qfix Systems, Avondale, PA) were evaluated as part of this study. The results indicate that the inserts are largely interchangeable across a given design type and that the measured WET values agree with those generated by the TPS with a maxi- mum difference less than 1 mm. The WET of the devices, as determined by the TPS, was not impacted by CT beam hardening normally experienced during clinical use. The reproduc- ibility of the WET method was also determined to be better than ±0.02 mm. In conclusion, the testing of immobilization prior to implementation in proton therapy is essential in order to ascertain their impact on the proton treatment and the methodology described here can also be applied to other immobilization systems.

  5. Chemical immobilization of antimicrobial peptides on biomaterial surfaces.

    PubMed

    Silva, Rafael R; Avelino, Karen Y P S; Ribeiro, Kalline L; Franco, Octavio L; Oliveira, Maria D L; Andrade, Cesar A S

    2016-01-01

    The hospital infections associated with surgical procedures and implants still represents a severe problem to modern society. Therefore, new strategies to combat bacterial infections mainly caused by microorganisms resistant to conventional antibiotics are extremely necessary. In this context, antimicrobial peptides have gained prominence due their biocompatibility, low toxicity and effectiveness. The immobilization of antimicrobial peptides (AMPs) onto a biomaterial surface is an excellent alternative to the development of new biodevices with microbicide properties. Herein, we describe reports related to physical-chemical characterization, in vitro/in vivo studies and clinical applicability. In this review, we focused on the AMPs mechanisms of action, different peptide immobilization strategies on solid surface and their microbicide effectiveness.

  6. Immobilization of phosphorus in cow manure during hydrothermal carbonization.

    PubMed

    Dai, Lichun; Tan, Furong; Wu, Bo; He, Mingxiong; Wang, Wenguo; Tang, Xiaoyu; Hu, Qichun; Zhang, Min

    2015-07-01

    The surplus of manure phosphorus (P) with increasing livestock production might pose a risk of P loss to the environment due to the high mobility of P in manure. Thus, there is an increasing need to mitigate P loss from manure. This study aimed to investigate the effect of hydrothermal carbonization (HTC) on the immobilization of P in cow manure. The results demonstrated that the P content in cow manure was increased substantially by ∼20% after HTC, while the water-extractable P (WEP) and Mehlich-3-extractable P (MEP) in manure was reduced significantly by >80% and 50%, respectively. The decrease in P solubility might result from the increased apatite P (increased by >85%) and decreased soluble Ca (decreased by ∼50%) after HTC. These results suggested that HTC could be an efficient strategy to immobilize P in cow manure, thereby potentially mitigating the P loss problem from cow manure.

  7. Active Acetylcholinesterase Immobilization on a Functionalized Silicon Surface.

    PubMed

    Khaldi, K; Sam, S; Gouget-Laemmel, A C; Henry de Villeneuve, C; Moraillon, A; Ozanam, F; Yang, J; Kermad, A; Ghellai, N; Gabouze, N

    2015-08-04

    In this work, we studied the attachment of active acetylcholinesterase (AChE) enzyme on a silicon substrate as a potential biomarker for the detection of organophosphorous (OP) pesticides. A multistep functionalization strategy was developed on a crystalline silicon surface: a carboxylic acid-terminated monolayer was grafted onto a hydrogen-terminated silicon surface by photochemical hydrosilylation, and then AChE was covalently attached through amide bonds using an activation EDC/NHS process. Each step of the modification was quantitatively characterized by ex-situ Fourier transform infrared spectroscopy in attenuated-total-reflection geometry (ATR-FTIR) and atomic force microscopy (AFM). The kinetics of enzyme immobilization was investigated using in situ real-time infrared spectroscopy. The enzymatic activity of immobilized acetylcholinesterase enzymes was determined with a colorimetric test. The surface concentration of active AChE was estimated to be Γ = 1.72 × 10(10) cm(-2).

  8. Hydrogen production from biodiesel byproduct by immobilized Enterobacter aerogenes.

    PubMed

    Han, Jinmi; Lee, Dohoon; Cho, Jinku; Lee, Jeewon; Kim, Sangyong

    2012-01-01

    The recent rapid growth of the biodiesel industry has generated a significant amount of glycerol as a byproduct. As a result, the price of glycerol is currently relatively low, making it an attractive starting material for the production of chemicals with higher values. Crude glycerol can be directly converted through microbial fermentation into various chemicals such as hydrogen. In this study, we optimized immobilization of a facultative hydrogen producing microorganism, Enterobacter aerogenes, with the goal of developing biocatalysts that was appropriate for the continuous hydrogen production from glycerol. Several carriers were tested and agar was found to be the most effective. In addition, it was clearly shown that variables such as the carrier content and cell loading should be controlled for the immobilization of biocatalysts with high hydrogen productivity, stability, and reusability. After optimization of these variables, we were able to obtain reusable biocatalysts that could directly convert the byproduct stream from biodiesel processes into hydrogen in continuous processes.

  9. Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: II. Heterotrophic conditions.

    PubMed

    Choix, Francisco J; de-Bashan, Luz E; Bashan, Yoav

    2012-10-10

    The effect of the bacterium Azospirillum brasilense jointly immobilized with Chlorella vulgaris or C. sorokiniana in alginate beads on total carbohydrates and starch was studied under dark and heterotrophic conditions for 144 h in synthetic growth medium supplemented with either d-glucose or Na-acetate as carbon sources. In all treatments, enhanced total carbohydrates and starch content per culture and per cell was obtained after 24h; only jointly immobilized C. vulgaris growing on d-glucose significantly increased total carbohydrates and starch content after 96 h. Enhanced accumulation of carbohydrate and starch under jointly immobilized conditions was variable with time of sampling and substrate used. Similar results occurred when the microalgae was immobilized alone. In both microalgae growing on either carbon sources, the bacterium promoted accumulation of carbohydrates and starch; when the microalgae were immobilized alone, they used the carbon sources for cell multiplication. In jointly immobilized conditions with Chlorella spp., affinity to carbon source and volumetric productivity and yield were higher than when Chlorella spp. were immobilized alone; however, the growth rate was higher in microalgae immobilized alone. This study demonstrates that under heterotrophic conditions, A. brasilense promotes the accumulation of carbohydrates in two strains Chlorella spp. under certain time-substrate combinations, producing mainly starch. As such, this bacterium is a biological factor that can change the composition of compounds in microalgae in dark, heterotrophic conditions.

  10. Cortical Reorganization after Hand Immobilization: The beta qEEG Spectral Coherence Evidences

    PubMed Central

    Fortuna, Marina; Teixeira, Silmar; Machado, Sérgio; Velasques, Bruna; Bittencourt, Juliana; Peressutti, Caroline; Budde, Henning; Cagy, Mauricio; Nardi, Antonio E.; Piedade, Roberto; Ribeiro, Pedro; Arias-Carrión, Oscar

    2013-01-01

    There is increasing evidence that hand immobilization is associated with various changes in the brain. Indeed, beta band coherence is strongly related to motor act and sensitive stimuli. In this study we investigate the electrophysiological and cortical changes that occur when subjects are submitted to hand immobilization. We hypothesized that beta coherence oscillations act as a mechanism underlying inter- and intra-hemispheric changes. As a methodology for our study fifteen healthy individuals between the ages of 20 and 30 years were subjected to a right index finger task before and after hand immobilization while their brain activity pattern was recorded using quantitative electroencephalography. This analysis revealed that hand immobilization caused changes in frontal, central and parietal areas of the brain. The main findings showed a lower beta-2 band in frontal regions and greater cortical activity in central and parietal areas. In summary, the coherence increased in the frontal, central and parietal cortex, due to hand immobilization and it adjusted the brains functioning, which had been disrupted by the procedure. Moreover, the brain adaptation upon hand immobilization of the subjects involved inter- and intra-hemispheric changes. PMID:24278213

  11. Removal of endocrine disrupting compounds from wastewater by microalgae co-immobilized in alginate beads.

    PubMed

    Solé, Alba; Matamoros, Víctor

    2016-12-01

    Microalgae systems have been found to be efficient for removing microcontaminants from wastewater effluents, but the effectiveness of immobilized microalgae for removing endocrine disrupting compounds (EDCs) has not yet been addressed. This paper assesses the effect of free and immobilized microalgae on removal efficiency for 6 EDCs by mixing them in 2.5 L reactors with treated wastewater. The experimental design also included control reactors without microalgae. After 10 days of incubation, 64 and 89% of the NH4-N and 90 and 96% of total phosphorous (TP) had been eliminated in the free microalgae and immobilized microalgae reactors, respectively, while the control reactors eliminated only 40% and 70% of the NH4-N and TP, respectively. Both the free and immobilized microalgae reactors were able to remove up to 80% of most of the studied EDCs within 10 days of incubation. Free microalgae were found to increase the kinetic removal rate for bisphenol A, 17-α-ethinylestradiol, and 4-octylphenol (25%, 159%, and 41%, respectively). Immobilizing the microalgae in alginate beads additionally enhanced the kinetic removal rate for bisphenol AF, bisphenol F, and 2,4-dichlorophenol. This study shows that the use of co-immobilized microalgae-based wastewater treatment systems increases the removal efficiency for nutrients and some EDCs from wastewater effluents.

  12. Immobilization of Arsenic by Vivianite Biomineralization

    NASA Astrophysics Data System (ADS)

    Kim, H.; Park, B.; Lee, I.; Roh, Y.

    2007-12-01

    Microbial metal reduction and biomineralization has the potential for immobilizing metals and radionuclides in subsurface environments. The objective of this study was to examine Fe reduction and biomineralization in the presence of arsenite or arsenate using metal-reducing bacteria, Shewanella sp. (Haejae-1), enriched from an intertidal flat sediment, South Korea. The bacteria was able to use glucose as an electron donor and Fe(III)-citrate as an electron acceptor in the presence of arsenite or arsenate using phosphate buffered saline medium. The reduction of Fe(III)-citrate in the presence of arsenite or arsenate resulted in the precipitation of white µm-sized crystalline minerals. XRD analysis of the white precipitate after 14-day incubation identified the mineral phase as vivianite. SEM with EDX analysis of the vivianite precipitated by the metal reducing bacteria confirmed the presence of Fe, As, O, and P. This study indicates that formation of sparingly soluble vivianite precipitates, mediated by the metal -reducing bacteria, may sequester iron, phosphate, and arsenic into more stable and less toxic forms. The formation of phosphate minerals has frequently been observed in sedimentary environments under high biological productivity, where organic matter serves as a source of phosphate to sediment pore water through bacterial degradation. Therefore, formation of sparingly soluble iron precipitates, mediated by the metal- reducing bacteria, may sequester iron, phosphate, and other metals into more stable and less toxic forms in subsurface environments.

  13. The study of the influence of temperature and initial glucose concentration on the fermentation process in the presence of Saccharomyces cerevisiae yeast strain immobilized on starch gels by reversed-flow gas chromatography.

    PubMed

    Lainioti, G Ch; Kapolos, J; Koliadima, A; Karaiskakis, G

    2012-01-01

    The technique of reversed-flow gas chromatography (RFGC) was employed for the determination of the alcoholic fermentation phases and of kinetic parameters for free and immobilized cell systems, at different initial glucose concentrations and temperature values. In addition to this, due to its considerable advantages over other techniques, RFGC was used for the characterization of a new biocatalyst, yeast cells immobilized on starch gel, and especially wheat starch gel. Immobilization of wine yeast Saccharomyces cerevisiae AXAZ-1 was accomplished on wheat and corn starch gels in order to prepare new biocatalysts with great interest for the fermentation industry. The RFGC led with great accuracy, resulting from a literature review, to the determination of reaction rate constants and activation energies at each phase of the fermentation processes. A maximum value of rate constants was observed at initial glucose concentration of 205 g/L, where a higher number of yeast cells was observed. The increase of glucose concentrations had a negative influence on the growth of AXAZ-1 cells and rate constants were decreased. The decrease of fermentation temperature caused a substantial reduction in the viability of immobilized cells as well as in rate constant values. Activation energies of corn starch gel presented lower values than those of wheat starch gel. However, the two supports showed higher catalytic efficiency than free cell systems, proving that starch gels may act as a promoter of the catalytic activity of the yeast cells involved in the fermentation process.

  14. Catalysis of rice straw hydrolysis by the combination of immobilized cellulase from Aspergillus niger on β-cyclodextrin-Fe3O4 nanoparticles and ionic liquid.

    PubMed

    Huang, Po-Jung; Chang, Ken-Lin; Hsieh, Jung-Feng; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11 U g immobilized cellulase(-1) at an ionic liquid concentration of 200 mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739 g h(-1) L(-1). One of the advantages of immobilized cellulase is high reusability--it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15 g L(-1)). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase.

  15. Catalysis of Rice Straw Hydrolysis by the Combination of Immobilized Cellulase from Aspergillus niger on β-Cyclodextrin-Fe3O4 Nanoparticles and Ionic Liquid

    PubMed Central

    Huang, Po-Jung; Chang, Ken-Lin; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11 U g immobilized cellulase−1 at an ionic liquid concentration of 200 mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739 g h−1 L−1. One of the advantages of immobilized cellulase is high reusability—it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15 g L−1). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase. PMID:25874210

  16. Immobilized redox mediator on metal-oxides nanoparticles and its catalytic effect in a reductive decolorization process.

    PubMed

    Alvarez, L H; Perez-Cruz, M A; Rangel-Mendez, J R; Cervantes, F J

    2010-12-15

    Different metal-oxides nanoparticles (MONP) including α-Al(2)O(3), ZnO and Al(OH)(3), were utilized as adsorbents to immobilize anthraquinone-2,6-disulfonate (AQDS). Immobilized AQDS was subsequently tested as a solid-phase redox mediator (RMs) for the reductive decolorization of the azo dye, reactive red 2 (RR2), by anaerobic sludge. The highest adsorption capacity of AQDS was achieved on Al(OH)(3) nanoparticles, which was ∼0.16 mmol g(-1) at pH 4. Immobilized AQDS increased up to 7.5-fold the rate of decolorization of RR2 by anaerobic sludge as compared with sludge incubations lacking AQDS. Sterile controls including immobilized AQDS did not show significant (<3.5%) RR2 decolorization, suggesting that physical-chemical processes (e.g. adsorption or chemical reduction) were not responsible for the enhanced decolorization achieved. Immobilization of AQDS on MONP was very stable under the applied experimental conditions and spectrophotometric screening did not detect any detachment of AQDS during the reductive decolorization of RR2, confirming that immobilized AQDS served as an effective RMs. The present study constitutes the first demonstration that immobilized quinones on MONP can serve as effective RMs in the reductive decolorization of an azo dye. The immobilizing technique developed could be applied in anaerobic wastewater treatment systems to accelerate the redox biotransformation of recalcitrant pollutants.

  17. [Oligonucleotide derivatives in the nucleic acid hybridization analysis. I. Covalent immobilization of oligonucleotide probes onto the nylon].

    PubMed

    Dmitrienko, E V; Pyshnaia, I A; Pyshnyĭ, D V

    2010-01-01

    The features of UV-induced immobilization of oligonucleotides on a nylon membranes and the effectiveness of enzymatic labeling of immobilized probes at heterophase detection of nucleic acids are studied. Short terminal oligothymidilate (up to 10 nt) sequences are suggested to attach to the probe via a flexible ethylene glycol based linker. The presence of such fragment enhances the intensity of immobilization and reduces UV-dependent degradation of the targeted (sequence-specific) part of the probe by reducing the dose needed for the immobilization of DNA. The optimum dose of UV-irradiation is determined to be ~0.4 J/cm(2) at the wavelength 254 nm. This dose provides high level of hybridization signal for immobilized probes with various nucleotide composition of the sequence specific moiety. The amide groups of the polyamide are shown to play the key role in the photoinduced immobilization of nucleic acids, whereas the primary amino groups in the structure of PA is not the center responsible for the covalent binding of DNA by UV-irradiation, as previously believed. Various additives in the soaking solution during the membrane of UV-dependent immobilization of probes are shown to influence its effectiveness. The use of alternative to UV-irradiation system of radical generation are shown to provide the immobilization of oligonucleotides onto the nylon membrane.

  18. Accumulation of uranium by immobilized persimmon tannin

    SciTech Connect

    Sakaguchi, Takashi; Nakajima, Akira )

    1994-01-01

    We have discovered that the extracted juice of unripe astringent persimmon fruit, designated as kakishibu or shibuol, has an extremely high affinity for uranium. To develop efficient adsorbents for uranium, we tried to immobilize kakishibu (persimmon tannin) with various aldehydes and mineral acids. Persimmon tannin immobilized with glutaraldehyde can accumulate 1.71 g (14 mEq U) of uranium per gram of the adsorbent. The uranium accumulating capacity of this adsorbent is several times greater than that of commercially available chelating resins (2-3 mEq/g). Immobilized persimmon tannin has the most favorable features for uranium recovery; high selective adsorption ability, rapid adsorption rate, and applicability in both column and batch systems. The uranium retained on immobilized persimmon tannin can be quantitatively and easily eluted with a very dilute acid, and the adsorbent can thus be easily recycled in the adsorption-desorption process. Immobilized persimmon tannin also has a high affinity for thorium. 23 refs., 13 figs., 7 tabs.

  19. Immobilization of DNAzyme as a thermostable biocatalyst.

    PubMed

    Ito, Yoshihiro; Hasuda, Hirokazu

    2004-04-05

    Deoxyribozyme (DNAzyme) carrying peroxidase activity was immobilized on two types of particles and the enzymatic activity was measured. The DNA recognizing porphyrin were prepared according to Travascio et al. ([1998] Chem Biol 5:505-517) and the interactions with hemin were investigated by ultraviolet absorbance and circular dichroism spectroscopies. The DNA interacted with hemin and significant conformational change was induced by the interaction. Therefore, the end of this DNA was modified with a thiol group and it was immobilized on thiol-containing polysaccharide beads or on gold particles. The DNA immobilized on the gold particle showed activity catalyzing the peroxidation reaction. No significant reduction of activity was observed even after immobilization. The immobilized DNAzyme could be repeatedly utilized without significant loss of activity. In addition, heat treatment did not reduce the activity, although a protein enzyme, horseradish peroxidase, lost its activity after the heat treatment. The repertoire of DNAzyme is still currently limited. However, in the future the utilization of DNAzyme in the field of biotechnology will be important with the increase of discoveries of new functional DNAzymes.

  20. Biomolecule immobilization techniques for bioactive paper fabrication.

    PubMed

    Kong, Fanzhi; Hu, Yim Fun

    2012-04-01

    Research into paper-based sensors or functional materials that can perform analytical functions with active recognition capabilities is rapidly expanding, and significant research effort has been made into the design and fabrication of bioactive paper at the biosensor level to detect potential health hazards. A key step in the fabrication of bioactive paper is the design of the experimental and operational procedures for the immobilization of biomolecules such as antibodies, enzymes, phages, cells, proteins, synthetic polymers and DNA aptamers on a suitably prepared paper membrane. The immobilization methods are concisely categorized into physical absorption, bioactive ink entrapment, bioaffinity attachment and covalent chemical bonding immobilization. Each method has individual immobilization characteristics. Although every biomolecule-paper combination has to be optimized before use, the bioactive ink entrapment method is the most commonly used approach owing to its general applicability and biocompatibility. Currently, there are four common applications of bioactive paper: (1) paper-based bioassay or paper-based analytical devices for sample conditioning; (2) counterfeiting and countertempering in the packaging and construction industries; (3) pathogen detection for food and water quality monitoring; and (4) deactivation of pathogenic bacteria using antimicrobial paper. This article reviews and compares the different biomolecule immobilization techniques and discusses current trends. Current, emerging and future applications of bioactive paper are also discussed.

  1. Active-site structure, binding and redox activity of the heme–thiolate enzyme CYP2D6 immobilized on coated Ag electrodes: a surface-enhanced resonance Raman scattering study

    PubMed Central

    Bonifacio, Alois; Millo, Diego; Keizers, Peter H. J.; Boegschoten, Roald; Commandeur, Jan N. M.; Vermeulen, Nico P. E.; Gooijer, Cees

    2007-01-01

    Surface-enhance resonance Raman scattering spectra of the heme–thiolate enzyme cytochrome P450 2D6 (CYP2D6) adsorbed on Ag electrodes coated with 11-mercaptoundecanoic acid (MUA) were obtained in various experimental conditions. An analysis of these spectra, and a comparison between them and the RR spectra of CYP2D6 in solution, indicated that the enzyme’s active site retained its nature of six-coordinated low-spin heme upon immobilization. Moreover, the spectral changes detected in the presence of dextromethorphan (a CYP2D6 substrate) and imidazole (an exogenous heme axial ligand) indicated that the immobilized enzyme also preserved its ability to reversibly bind a substrate and form a heme–imidazole complex. The reversibility of these processes could be easily verified by flowing alternately solutions of the various compounds and the buffer through a home-built spectroelectrochemical flow cell which contained a sample of immobilized protein, without the need to disassemble the cell between consecutive spectral data acquisitions. Despite immobilized CYP2D6 being effectively reduced by a sodium dithionite solution, electrochemical reduction via the Ag electrode was not able to completely reduce the enzyme, and led to its extensive inactivation. This behavior indicated that although the enzyme’s ability to exchange electrons is not altered by immobilization per se, MUA-coated electrodes are not suited to perform direct electrochemistry of CYP2D6. Electronic supplementary material The online version of this article (doi:10.1007/s00775-007-0303-1) contains supplementary material, which is available to authorized users. PMID:17899220

  2. The effect of mineral carrier composition on phosphate-accumulating bacteria immobilization.

    PubMed

    Hrenovic, J; Ivankovic, T; Tibljas, D

    2009-07-30

    The goal of this study was to determine the dynamics and yield of immobilization of the phosphate-accumulating bacterium Acinetobacter junii on mineral carriers. As mineral carriers natural clinoptilolite tuff from Turkey (T) and Serbia (S) and natural bentonite (TER), in original and magnesium (Mg)-exchanged form were used. The key feature which determined the extent of immobilization of A. junii was the type of carrier; the immobilization yield decreased in order T>TER>S. The number of immobilized cells was significantly higher for the Mg-exchanged carriers when compared to their original counterparts (95 and 75 x 10(8)CFU g(-1) for T, 74 and 58 x 10(8)CFU g(-1) for TER, 19 and 6 x 10(8)CFU g(-1) for S). The Mg-exchanged T and S displayed a prolonged biofilm growth up to 24h, while the original counterparts reached the mature biofilm after 12h of incubation. Both forms of TER reached the mature biofilm after 24h of incubation, due to swelling property of the material. The number of immobilized cells correlated significantly negatively with particle size of the carrier, indicating that particle size is another important feature which determined the extent of immobilization. The Mg-exchange of original carriers resulted in significant increase of the zeta potential. When all of the materials were compared, the increase of the zeta potential of carriers correlated negatively with the number of immobilized cells, suggesting that the zeta potential of material is not a crucial factor which determined the immobilization of cells.

  3. pH dependent immobilization of Urease on glutathione capped gold nanoparticles.

    PubMed

    Garg, Seema; De, Arnab; Mozumdar, Subho

    2014-09-08

    Urease is a nickel-dependent metallonzyme that catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. Although the enzyme serves a significant role in several detoxification and analytical processes, its usability is restricted due to high cost, availability in small amounts, instability and a limited possibility of economic recovery from a reaction mixture. Hence, there is a need to develop an efficient, simple and reliable immobilization strategy for the enzyme. In this work, the carboxyl terminated surface of glutathione capped gold nanoparticles have been utilized as a solid support for the covalent attachment of Urease. The immobilization has been carried out at different pH conditions so as to elucidate its effect on the immobilization efficiency and enzyme bio-activity. The binding of the enzyme has been quantitatively and qualitatively analyzed through techniques like UV-Vis spectroscopy, intrinsic steady state fluorescence and Circular Dichorism. The bio-activity of the immobilized enzyme was investigated with respect to the native enzyme under different thermal conditions. Recyclability and shelf life studies of the immobilized enzyme have also been carried out. Results reveal that the immobilization is most effective at pH of 7.4 followed by that in an acidic medium and is least in alkaline environment. The immobilized enzyme also exhibits enhance activity in comparison to the native form at physiological temperature. The immobilized urease (on gold glutathione nano-conjugates surface) can be effectively employed for biosensor fabrication, immunoassays and as an in vivo diagnostic tool in the future.

  4. Airline Chair-rest Deconditioning: Induction of Immobilization Thromboemboli?

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Rehrer, N. J.; Mohler, S. R.; Quach, D. T.; Evans, D. G.; Dalton, Bonnie P. (Technical Monitor)

    2002-01-01

    Air passenger miles will likely double by year 2020. The altered and restrictive environment in an airliner cabin can influence hematological homeostasis in passengers and crew. Flight-related deep various thromboemboli (DVT) have been associated with at least 577 deaths on 42 of 120 airlines from 1977 to 1984 (25 deaths/million departures), whereas many such cases go unreported. However, there are four major factors that could influence formation of possible flight-induced DVT: sleeping accomodations (via sitting immobilization), travelers' medical history (via tissue injury), cabin environmental factors (via lower partial pressure of oxygen and lower relative humidity), and the more encompassing chair-rest deconditioning (C-RD) syndrome. There is ample evidence that recent injury and surgery (especially in deconditioned hospitalized patients) facilitate thrombophlebitis and formation of DVT that may be exacerbated by the immobilization of prolonged air travel. In the healthy flying population immobilization factors associated with prolonged (> 5 hr) C-RID such as total body dehydration, hypovolemia and increased blood viscosity, and reduced various blood flow (pooling) in the legs may facilitate formation of DVT. However, data from at least four case-controlled epidemiological studies did not confirm a direct causative relationship between air travel and DART, but factors such as history of vascular thromboemboli, various insufficiency, chronic heart failure, obesity, immobile standing position, more than 3 pregnancies, infectious disease, long-distance travel, muscular trauma and violent physical effort were significantly more frequent in DVT patients than in controls. Thus, there is no clear, direct evidence yet that prolonged sitting in airliner seats, or prolonged experimental chair-rest- or bed- rest-deconditioning treatments cause deep various thromboemboli in healthy people.

  5. Chemoenzymatic Reversible Immobilization and Labeling of Proteins without Prior Purification

    PubMed Central

    Rashidian, Mohammad; Song, James M.; Pricer, Rachel E.; Distefano, Mark D.

    2012-01-01

    Site-specific chemical modification of proteins is important for many applications in biology and biotechnology. Recently, our laboratory and others have exploited the high specificity of the enzyme protein farnesyltransferase (PFTase) to site-specifically modify proteins through the use of alternative substrates that incorporate bioorthogonal functionality including azides and alkynes. In this study, we evaluate two aldehyde-containing molecules as substrates for PFTase and as reactants in both oxime and hydrazone formation. Using green fluorescent protein (GFP) as a model system, we demonstrate that the purified protein can be enzymatically modified with either analogue to yield aldehyde-functionalized proteins. Oxime or hydrazone formation was then employed to immobilize, fluorescently label or PEGylate the resulting aldehyde-containing proteins. Immobilization via hydrazone formation was also shown to be reversible via transoximization with a fluorescent alkoxyamine. After characterizing this labeling strategy using pure protein, the specificity of the enzymatic process was used to selectively label GFP present in crude E. coli extract followed by capture of the aldehyde-modified protein using hydrazide-agarose. Subsequent incubation of the immobilized protein using a fluorescently labeled or PEGylated alkoxyamine resulted in the release of pure GFP containing the desired site-specific covalent modifications. This procedure was also employed to produce PEGylated glucose-dependent insulinotropic polypeptide (GIP), a protein with potential therapeutic activity for diabetes. Given the specificity of the PFTase-catalyzed reaction coupled with the ability to introduce a CAAX-box recognition sequence onto almost any protein, this method shows great potential as a general approach for the selective immobilization and labeling of recombinant proteins present in crude cellular extract without prior purification. Beyond generating site-specifically modified proteins

  6. Chemoenzymatic reversible immobilization and labeling of proteins without prior purification.

    PubMed

    Rashidian, Mohammad; Song, James M; Pricer, Rachel E; Distefano, Mark D

    2012-05-23

    Site-specific chemical modification of proteins is important for many applications in biology and biotechnology. Recently, our laboratory and others have exploited the high specificity of the enzyme protein farnesyltransferase (PFTase) to site-specifically modify proteins through the use of alternative substrates that incorporate bioorthogonal functionality including azides and alkynes. In this study, we evaluate two aldehyde-containing molecules as substrates for PFTase and as reactants in both oxime and hydrazone formation. Using green fluorescent protein (GFP) as a model system, we demonstrate that the purified protein can be enzymatically modified with either analogue to yield aldehyde-functionalized proteins. Oxime or hydrazone formation was then employed to immobilize, fluorescently label, or PEGylate the resulting aldehyde-containing proteins. Immobilization via hydrazone formation was also shown to be reversible via transoximization with a fluorescent alkoxyamine. After characterizing this labeling strategy using pure protein, the specificity of the enzymatic process was used to selectively label GFP present in crude E. coli extract followed by capture of the aldehyde-modified protein using hydrazide-agarose. Subsequent incubation of the immobilized protein using a fluorescently labeled or PEGylated alkoxyamine resulted in the release of pure GFP containing the desired site-specific covalent modifications. This procedure was also employed to produce PEGylated glucose-dependent insulinotropic polypeptide (GIP), a protein with potential therapeutic activity for diabetes. Given the specificity of the PFTase-catalyzed reaction coupled with the ability to introduce a CAAX-box recognition sequence onto almost any protein, this method shows great potential as a general approach for selective immobilization and labeling of recombinant proteins present in crude cellular extract without prior purification. Beyond generating site-specifically modified proteins, this

  7. Characterization of a new stationary phase based on microwave immobilized polybutadiene on titanium oxide-modified silica.

    PubMed

    Morais, Lais S R; Jardim, Isabel C S F

    2005-05-06

    Titanium oxide-modified silica was prepared by reaction of silica with titanium tetrabutoxide and then was used as support in the preparation of stationary phases with self-immobilized polybutadiene (PBD) and PBD immobilized through microwave radiation. Chromatographic performance of the stationary phases was evaluated in terms of the efficiency (plates/m), asymmetry (A(s)), retention factor (k) and resolution (R(s)) of two standard sample mixtures, one of then containing the basic compound N,N-dimethylaniline. A microwave irradiation of 30 min at 520 W gave the best efficiency (86,500 N m(-1)), greater than that of a 6-day self immobilized phase (69,500 N m(-1)). Self-immobilized stationary phases prepared with bare silica were also studied for comparison. These resulted in lower chromatographic performance, 43,800 N m(-1), when compared to the self-immobilized phase prepared with titanized silica.

  8. Possible role of NO modulators in protective effect of trazodone and citalopram (antidepressants) in acute immobilization stress in mice.

    PubMed

    Kumar, Anil; Garg, Ruchika; Gaur, Vaibhav; Kumar, Puneet

    2010-11-01

    Stress is an aversive stimulus which disturbs physiological homeostasis and is reflected on a variety of biological systems. The present study was designed to investigate the nitric oxide mechanism in neuroprotective effect of trazodone and citalopram against acute immobilization-induced behavioral and biochemical alteration in mice. Mice were immobilized for a 6 h. Acute immobilization stress caused anxiety, hyperalgesia, impaired locomotor activity and oxidative damage. Pretreatment with trazodone and citalopram significantly reversed immobilized stress-induced behavioral and biochemical alterations. L-arginine, pretreatment with trazodone or citalopram significantly reversed their protective effects. However, L-NAME or methylene blue pretreatment with trazodone or citalopram significantly potentiated their protective effects alone. Results suggest the involvement of nitric oxide pathways in the protective effect of trazodone and citalopram against immobilization stress induced behavioral and biochemical alterations.

  9. Illusory movements prevent cortical disruption caused by immobilization.

    PubMed

    Roll, R; Kavounoudias, A; Albert, F; Legré, R; Gay, A; Fabre, B; Roll, J P

    2012-08-01

    Enforced limb disuse strongly disrupts the cortical networks that are involved in sensorimotor activities. This disruption causes a cortical reorganization that may be functionally maladaptive. In this study, we used functional magnetic resonance imaging (fMRI) to investigate whether it is possible to prevent this reorganization by compensating for the lack of actual kinesthetic perception with illusory movements induced by "neuromimetic" proprio-tactile feedback that is artificially delivered during immobilization. Sixteen healthy volunteers were equipped for five days with full-hand ortheses that prevented them from performing finger and hand movements but allowed for kinesthetic and tactile sensations. Eight participants received a twice-daily proprio-tactile treatment consisting of the perception of kinesthetic sensations resembling those felt during actual movements generated by miniature vibrators set in the ortheses at the finger and wrist levels. Eight untreated participants received no stimulation. The effects of hand immobilization and treatment were assessed by fMRI during a calibrated voluntary hand movement task and hand tactile stimulation before cast placement and immediately after cast removal. We found that the sensorimotor network was preserved in subjects who underwent this treatment during hand immobilization, while the sensorimotor network of untreated subjects was significantly altered. These findings suggest that sensory feedback and associated movement perception may counteract disuse-induced cortical plastic changes through recruitment of a large part of the cortical network used for actual performed movement. The possibility of guiding cortical plasticity with proprioceptive augmented feedback is potentially relevant for rehabilitation efforts.

  10. Potential Applications of Carbohydrases Immobilization in the Food Industry

    PubMed Central

    Contesini, Fabiano Jares; de Alencar Figueira, Joelise; Kawaguti, Haroldo Yukio; de Barros Fernandes, Pedro Carlos; de Oliveira Carvalho, Patrícia; Nascimento, Maria da Graça; Sato, Hélia Harumi

    2013-01-01

    Carbohydrases find a wide application in industrial processes and products, mainly in the food industry. With these enzymes, it is possible to obtain different types of sugar syrups (viz. glucose, fructose and inverted sugar syrups), prebiotics (viz. galactooligossacharides and fructooligossacharides) and isomaltulose, which is an interesting sweetener substitute for sucrose to improve the sensory properties of juices and wines and to reduce lactose in milk. The most important carbohydrases to accomplish these goals are of microbial origin and include amylases (α-amylases and glucoamylases), invertases, inulinases, galactosidases, glucosidases, fructosyltransferases, pectinases and glucosyltransferases. Yet, for all these processes to be cost-effective for industrial application, a very efficient, simple and cheap immobilization technique is required. Immobilization techniques can involve adsorption, entrapment or covalent bonding of the enzyme into an insoluble support, or carrier-free methods, usually based on the formation of cross-linked enzyme aggregates (CLEAs). They include a broad variety of supports, such as magnetic materials, gums, gels, synthetic polymers and ionic resins. All these techniques present advantages and disadvantages and several parameters must be considered. In this work, the most recent and important studies on the immobilization of carbohydrases with potential application in the food industry are reviewed. PMID:23344046

  11. Properties of immobile hydrogen confined in microporous carbon

    DOE PAGES

    Bahadur, Jitendra; Bhabha Atomic Research Centre; Contescu, Cristian I.; ...

    2017-03-06

    The mobility of H2 confined in microporous carbon was studied as a function of temperature and pressure using inelastic neutron scattering, and the translational and rotational motion of H2 molecules has been probed. At low loading, rotation of H2 molecules adsorbed in the smallest carbon pores (~6 ) is severely hindered, suggesting that the interaction between H2 and the host matrix is anisotropic. At higher loading, H2 molecules behave as nearly free rotor, implying lower anisotropic interactions with adsorption sites. At supercritical temperatures where bulk H2 is a gas, the inelastic spectrum of confined H2 provides evidence of a significantmore » fraction of immobile, solid-like hydrogen. The onset temperature for molecular mobility depends strongly on the loaded amount. The fraction of immobile molecules increases with pressure and attains a plateau at high pressures. Surprisingly, immobile H2 is present even at temperatures as high as ~110 K. This research at ORNL s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. Department of Energy. This research was supported in part by the ORNL Postdoctoral Research Associates Program, administered jointly by the ORNL and the Oak Ridge Institute for Science and Education. CIC and NCG acknowledge support from the Materials Science and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy.« less

  12. Continuous alcohol fermentation in an immobilized cell rotating disk reactor

    SciTech Connect

    Del Borghi, M.; Converti, A.; Parisi, F.; Ferraiolo, G.

    1985-01-01

    The increasing interest in alcohol fermentation over these last years because of the energy crisis has been demonstrated by an increase in scientific research. After a brief analysis of the main results of the literature in the field of alcohol fermentation reactors, the use of a new type of immobilized cell reactor (the rotating biological surface (RBS) reactor) was studied. As is well known, the RBS reactor is a form of fixed-film reactor and can be described as a dynamic trickling filter. The experimental apparatus employed a spongy material to trap the yeast cells on the disks. The results of fermentations carried out in the RBS reactor working in batch, in continuous with cell support, and in continuous without cell support have been presented in order to compare the different productivities and to assess the performance of the RBS immobilized cell reactor. An ethanol productivity of 7.1 g/L h was achieved in the RBS-ICR at a dilution rate of 0.3 h/sup -1/, 2.5 times higher than the maximum productivity obtained in the RBS reactor without support at a lower dilution rate. The adoption of a spongy material as a cell immobilizer, combined with the use of the RBS reactor, enhances the particular advantages of both systems.

  13. Tailoring immobilization of immunoglobulin by excimer laser for biosensor applications.

    PubMed

    Sima, Felix; Axente, Emanuel; Ristoscu, Carmen; Mihailescu, Ion N; Kononenko, Taras V; Nagovitsin, Ilya A; Chudinova, Galina; Konov, Vitaly I; Socol, Marcela; Enculescu, Ionut; Sima, Livia E; Petrescu, Stefana M

    2011-02-01

    The sheltered transfer and immobilization of rabbit anti-human antiserum immunoglobulin G (IgG) by matrix-assisted pulsed laser evaporation (MAPLE) are reported. The iced targets submitted to laser irradiation consisted of 0.2-2 mg/mL IgG blended or not with lipid (L-α-phosphatidylcholine dipalmitoyl) dissolved in distilled water-based saline buffer. Thin IgG coatings were obtained at room temperature onto glass, fused silica, or silicon substrates. Ten thousand subsequent laser pulses of 0.33, 0.5, or 0.67 J/cm(2) fluence were applied for the synthesis of each sample. Morphology and composition of the thin films were studied by optical, scanning, and atomic force microscopy and Fourier transformed infrared spectrometry. Optical labeling methods such as spectrofluorimetry and fluorescence microscopy were selected to verify the biosensor transduction principle because of their high sensitivity for detecting low amounts of antigen (IgG). Protein immobilization to the substrate surface was demonstrated for all obtained structures after immersion in the donkey anti-rabbit secondary antibody solution. The IgG transfer and immobilization onto substrates were improved by addition of lipid to MAPLE solutions.

  14. Controlling enzymatic activity by immobilization on graphene oxide.

    PubMed

    Bolibok, Paulina; Wiśniewski, Marek; Roszek, Katarzyna; Terzyk, Artur P

    2017-04-01

    In this study, graphene oxide (GO) has been applied as a matrix for enzyme immobilization. The protein adsorption capacity of GO is much higher than of other large surface area carbonaceous materials. Its structure and physicochemical properties are reported beneficial also for enzymatic activity modifications. The experimental proof was done here that GO-based biocatalytic systems with immobilized catalase are modifiable in terms of catalyzed reaction kinetic constants. It was found that activity and stability of catalase, considered here as model enzyme, closely depend on enzyme/GO ratio. The changes in kinetic parameters can be related to secondary structure alterations. The correlation between enzyme/GO ratio and kinetic and structure parameters is reported for the first time and enables the conscious control of biocatalytic processes and their extended applications. The biological activity of obtained biocatalytic systems was confirmed in vitro by the use of functional test. The addition of immobilized catalase improved the cells' viability after they were exposed to hydrogen peroxide and tert-butyl-hydroperoxide used as source of reactive oxygen species.

  15. Potential applications of carbohydrases immobilization in the food industry.

    PubMed

    Contesini, Fabiano Jares; de Alencar Figueira, Joelise; Kawaguti, Haroldo Yukio; de Barros Fernandes, Pedro Carlos; de Oliveira Carvalho, Patrícia; da Graça Nascimento, Maria; Sato, Hélia Harumi

    2013-01-11

    Carbohydrases find a wide application in industrial processes and products, mainly in the food industry. With these enzymes, it is possible to obtain different types of sugar syrups (viz. glucose, fructose and inverted sugar syrups), prebiotics (viz. galactooligossacharides and fructooligossacharides) and isomaltulose, which is an interesting sweetener substitute for sucrose to improve the sensory properties of juices and wines and to reduce lactose in milk. The most important carbohydrases to accomplish these goals are of microbial origin and include amylases (α-amylases and glucoamylases), invertases, inulinases, galactosidases, glucosidases, fructosyltransferases, pectinases and glucosyltransferases. Yet, for all these processes to be cost-effective for industrial application, a very efficient, simple and cheap immobilization technique is required. Immobilization techniques can involve adsorption, entrapment or covalent bonding of the enzyme into an insoluble support, or carrier-free methods, usually based on the formation of cross-linked enzyme aggregates (CLEAs). They include a broad variety of supports, such as magnetic materials, gums, gels, synthetic polymers and ionic resins. All these techniques present advantages and disadvantages and several parameters must be considered. In this work, the most recent and important studies on the immobilization of carbohydrases with potential application in the food industry are reviewed.

  16. Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization

    NASA Technical Reports Server (NTRS)

    Tucker, K. R.; Seider, M. J.; Booth, F. W.

    1981-01-01

    Noting that protein synthesis declines in the gastrocnemius 6 hr after immobilization, the study sought to detect an increase of protein synthesis when the limb was freed, and to examine the effects of exercise on the rate of increase. Rats were used as subjects, with their hind legs in plaster of Paris in plantar flexion to eliminate strain on the gastrocnemius. Periods of immobilization were varied and samples of blood from the muscle were taken to track protein synthesis rates for different groups in immobilization and exercise regimens (running and weightlifting). Synthesis rates declined 3.6% during time in the cast, then increased 6.3%/day after the casts were removed. Both running and weightlifting were found to increase the fractional rate of protein formation in the gastrocnemius muscle when compared with contralateral muscles that were not exercised and were used as controls, suggesting that the mechanism controlling protein synthesis in skeletal muscles is rapidly responsive to changes in muscular contractile activity.

  17. [The combined action of drinking mineral water and low-intensity electromagnetic radiation under the immobilization stress conditions (an experimental study)].

    PubMed

    Korolev, Yu N; Bobrovnitsky, I P; Geniatulina, M S; Mikhailik, L V; Nikulina, L A; Bobkova, A S; Yakovlev, M Yu

    2015-01-01

    The present study carried out on white male rats in experiments with the use of biochemical, radioimmunological, and electron- microscopic methods. It was shown that the combined treatment with potable mineral water (MV) and low-intensity electromagnetic radiation (LIEMR) of ultrahigh frequency (power density less than 1 pW/cm2, the frequency about 1000 MHz) facilitated the activation of metabolic and intracellular regenerative processes in the liver and testes. One of the advantages of the combined application of MV and LIEMR over the single-factor treatment manifested itself as the weakening of stress reactions, the increase in the frequency of the plastic processes, and the more harmonious development of different forms of intracellular regeneration. The results of the study provide a deeper insight ino the mechanisms underlying the combined actions of drinking mineral water and low-intensity electromagnetic radiation; also, they justify the application of these factors for the protection of the reproductive system and the entire body from stress-induced disorders.

  18. Immobilization of denatured DNA to macroporous supports: I. Efficiency of different coupling procedures.

    PubMed

    Bünemann, H; Westhoff, P; Herrmann, R G

    1982-11-25

    Methods commonly used for covalent immobilization of single stranded DNA have been applied to several solid supports (Sephadex G-25 and Cellex 410) as well as to a number of macroporous materials (Sepharose C1-6B, C1-2B; Sephacryl S-500 and S-1000). Coupling efficiencies and stability of covalently bound DNA are compared for both classes of materials. The yields of the immobilization reaction for sonicated DNA are only 10-40% for G-25 and Cellex 410 in contrast to 60-80% for C1-6B and S-500. Under optimal conditions, up to 0.5 mg of DNA can be coupled initially per g of wet macroporous material. The immobilized DNAs are lost from the supports in a biphasic manner, with about 10-20% loss per day during the first 2-3 days at 45 degrees C, followed by only about 1% loss per day at the same temperature thereafter. The influence of the coupling procedure on the generation of mismatch effects has been studied in 2.4 M tetraethylammonium chloride solution for the hybrid formation between immobilized and mobile DNA. The degree of mismatch ranged from 0-3% and depended on the method of immobilization. The unspecific absorption of DNA on macroporous materials is sufficiently low to allow efficient hybrid selection. No size limitations have been observed when plastid mRNAs are selected by cloned fragments of plastid DNA immobilized to macroporous Sephacryl S-500.

  19. Wheat Bran Enhances the Cytotoxicity of Immobilized Alcaligenes aquatilis F8 against Microcystis aeruginosa

    PubMed Central

    Sun, Pengfei; Lin, Hui; Wang, Guan; Zhang, Ximing; Zhang, Qichun; Zhao, Yuhua

    2015-01-01

    Algicidal bacteria offer a promising option for killing cyanobacteria. Therefore, a new Alcaligenes aquatilis strain F8 was isolated to control Microcystis aeruginosa in this study. The algicidal activity of strain F8 was dependent on the cell density of M. aeruginosa, and the maximal algicidal rate of the free bacterium reached 88.45% within 72 h. With a view to its application to the control of M. aeruginosa in the natural environment, strain F8 was immobilized in sodium alginate beads, but immobilization of the strain decreased its algicidal rate compared to that of the free bacterium. However, addition of wheat bran to the sodium alginate matrix used to immobilize strain F8 not only eliminated the adverse effects of immobilization on the bacteria but also resulted in an 8.83% higher algicidal rate of the immobilized than free bacteria. Exclusion and recovery methods were used to identify key ingredients of wheat bran and gain insight into the mechanism underlying the observed enhancement of algicidal activity. This analysis indicated that certain factors in wheat bran, including vitamins B1, B2, B9, and E were responsible for promoting bacterial growth and thereby improving the algicidal rate of immobilized strain F8. Our findings indicate that wheat bran is able to improve the algicidal efficiency of A. aquatilis strain F8 for killing M. aeruginosa and is a good source of not only carbon and nitrogen but also vitamins for bacteria. PMID:26295573

  20. The removal of thermo-tolerant coliform bacteria by immobilized waste stabilization pond algae.

    PubMed

    Pearson, H W; Marcon, A E; Melo, H N

    2011-01-01

    This study investigated the potential of laboratory- scale columns of immobilized micro-algae to disinfect effluents using thermo-tolerant coliforms (TTC) as a model system. Cells of a Chlorella species isolated from a waste stabilization pond complex in Northeast Brazil were immobilized in calcium alginate, packed into glass columns and incubated in contact with TTC suspensions for up to 24 hours. Five to six log removals of TTC were achieved in 6 hours and 11 log removals in 12 hours contact time. The results were similar under artificial light and shaded sunlight. However little or no TTC removal occurred in the light in columns of alginate beads without immobilized algae present or when the immobilized algae were incubated in the dark suggesting that the presence of both algae and light were necessary for TTC decay. There was a positive correlation between K(b) values for TTC and increasing pH in the effluent from the immobilized algal columns within the range pH 7.2 and 8.9. The potential of immobilized algal technology for wastewater disinfection may warrant further investigation.

  1. Immobilization of Microbes for Bioremediation of Crude Oil Polluted Environments: A Mini Review

    PubMed Central

    Bayat, Zeynab; Hassanshahian, Mehdi; Cappello, Simone

    2015-01-01

    Petroleum hydrocarbons are the most common environmental pollutants in the world and oil spills pose a great hazard to terrestrial and marine ecosystems. Oil pollution may arise either accidentally or operationally whenever oil is produced, transported, stored and processed or used at sea or on land. Oil spills are a major menace to the environment as they severely damage the surrounding ecosystems. To improve the survival and retention of the bioremediation agents in the contaminated sites, bacterial cells must be immobilized. Immobilized cells are widely tested for a variety of applications. There are many types of support and immobilization techniques that can be selected based on the sort of application. In this review article, we have discussed the potential of immobilized microbial cells to degrade petroleum hydrocarbons. In some studies, enhanced degradation with immobilized cells as compared to free living bacterial cells for the treatment of oil contaminated areas have been shown. It was demonstrated that immobilized cell to be effective and is better, faster, and can be occurred for a longer period PMID:26668662

  2. Immobilized heparin and its anti-coagulation effect on polysulfone membrane surface.

    PubMed

    Ren, Xiaoshuai; Xu, Ling; Xu, Jianxia; Zhu, Peizhi; Zuo, Li; Wei, Shicheng

    2013-01-01

    Polysulfone has been widely used as hemodialysis membrane material because of its excellent physiochemical performance. There is still a need to further improve its anti-coagulation property in clinical practice. In this work, we covalently immobilized heparin onto polysulfone membrane to improve its anti-coagulation performance. Low temperature plasma technique with environmentally friendly nitrogen as the gas source, as well as N-ethyl-N'-[3-dimethylaminopropy] carbodiimide hydrochloride/hydroxy-2,5-dioxopyrolidine-3-sulfonicacid sodium chemistry were utilized to immobilize heparin onto the surface of polysulfone membrane. X-ray photoelectron spectroscopy, attenuated total reflectance Fourier-transform infrared spectroscopy, as well as water contact angle results confirmed successful binding of heparin to the membrane surface. Only slight permeability differences were observed between the immobilized surface and the unmodified surface, while the polysulfone membrane had become more hydrophilic after immobilization. The blood coagulation time was greatly prolonged after modification and less platelets adhesion was observed on the heparin immobilized surface. Also, compared with heparin injection doses in clinical, the heparinized process in our work consumed less heparin. Our study suggests that the immobilized heparin has local anti-coagulation effect, while reducing the doses.

  3. Recovery of skeletal muscle after 3 mo of hindlimb immobilization in rats

    NASA Technical Reports Server (NTRS)

    Booth, F. W.; Seider, M. J.

    1979-01-01

    During immobilization, skeletal muscle undergoes decreases in size and strength with concomitant atrophic and degenerative changes in slow-twitch muscle fibers. Currently there are no objective data in slow-twitch muscle demonstrating recovery of biochemical or physiological indices following termination of immobilization. The purpose of this study was to determine whether the soleus, a slow-twitch muscle, could recover normal biochemical or physiological levels following termination of immobilization. Adenosine triphosphate, glycogen, and protein concentration (mg/g wet wt) all significantly decreased following 90 days of hindlimb immobilization, but these three values returned to control levels by the 60th recovery day. Similarly, soleus muscle wet weight and protein content (mg protein/muscle) returned to control levels by the 14th recovery day. In contrast, maximal isometric tension did not return to normal until the 120th day. These results indicate that following muscular atrophy, which was achieved through 90 days of hindlimb immobilization, several biochemical and physiological values in skeletal muscle are recovered at various times after the end of immobilization.

  4. Influence of silica-derived nano-supporters on cellobiase after immobilization.

    PubMed

    Wang, Peng; Hu, Xiaoke; Cook, Sean; Hwang, Huey-Min

    2009-07-01

    Core shell magnetite nanoparticle (CSMN) was successfully synthesized with diameter around 125 nm according to the determination with scanning electronic microscopy. SBA-15 with diameter around 31 nm was synthesized in our previous work as another supporter for immobilized degradation enzymes. The aim of this study was to investigate the influence of silica-derived nano-supporters on cellobiase after immobilization. With covalent method, glutaraldehyde was introduced to immobilize cellobiase. The immobilized enzyme efficiency, specific activity, and its characterization, including optimum pH, pH stability, optimum temperature for enzyme reaction, and enzyme thermal stability were investigated. Results show that the method of enzyme immobilization on both nano-supporters could improve cellobiase stability under low pH and high temperature conditions compared with the free enzyme. In the aspect of immobilization efficiency, SBA had higher amount of bounded protein than that of CSMN, but had lower specific enzyme activity than CSMN, assumably due to the change in silica surface properties caused by process of supporter synthesis.

  5. Enzyme-immobilized nanofiltration membrane to mitigate biofouling based on quorum quenching.

    PubMed

    Kim, Jae-Hyuk; Choi, Dong-Chan; Yeon, Kyung-Min; Kim, Sang-Ryong; Lee, Chung-Hak

    2011-02-15

    Recently, enzymatic quorum quenching (in the form of a free enzyme or an immobilized form on a bead) was successfully applied to a submerged membrane bioreactor with a microfiltration membrane for wastewater treatment as a novel approach to control membrane biofouling. In this study, a quorum quenching enzyme (acylase) was directly immobilized onto a nanofiltration membrane to mitigate biofouling in a nanofiltration process. In a flow cell experiment, the acylase-immobilized membrane with quorum quenching activity prohibited the formation of mushroom-shaped mature biofilm due to the reduced secretion of extracellular polymeric substances (EPS). The acylase-immobilized membrane maintained more than 90% of its initial enzyme activity for more than 20 iterative cycles of reaction and washing procedure. In the lab-scale continuous crossflow nanofiltration system operated at a constant pressure of 2 bar, the flux with the acylase-immobilized nanofiltration (NF) membrane was maintained at more than 90% of its initial flux after a 38-h operation, whereas that with the raw NF membrane decreased to 60% accompanied with severe biofouling. The quorum quenching activity of the acylase-immobilized membrane was also confirmed by visualizing the spatial distribution of cells and polysaccharides on the surface of each membrane using confocal laser scanning microscopy (CLSM) image analysis technique.

  6. Immobilized Bioluminescent Reagents in Flow Injection Analysis.

    NASA Astrophysics Data System (ADS)

    Nabi, Abdul

    Available from UMI in association with The British Library. Bioluminescent reactions exhibits two important characteristics from an analytical viewpoint; they are selective and highly sensitive. Furthermore, bioluminescent emissions are easily measured with a simple flow-through detector based on a photomultiplier tube and the rapid and reproducible mixing of sample and expensive reagent is best achieved by a flow injection manifold. The two most important bioluminescent systems are the enzyme (luciferase)/substrate (luciferin) combinations extracted from fireflies (Photinus pyralis) and marine bacteria (Virio harveyi) which requires ATP and NAD(P)H respectively as cofactors. Reactions that generate or consume these cofactors can also be coupled to the bioluminescent reaction to provide assays for a wide range of clinically important species. A flow injection manifold for the study of bioluminescent reactions is described, as are procedures for the extraction, purification and immobilization of firefly and bacterial luciferase and oxidoreductase. Results are presented for the determination of ATP using firefly system and the determination of other enzymes and substrates participating in ATP-converting reactions e.g. creatine kinase, ATP-sulphurylase, pyruvate kinase, creatine phosphate, pyrophosphate and phophoenolypyruvate. Similarly results are presented for the determination of NAD(P)H, FMN, FMNH_2 and several dehydrogenases which produce NAD(P)H and their substrates, e.g. alcohol, L-lactate, L-malate, L-glutamate, Glucose-6-phosphate and primary bile acid.

  7. Interactions among osteoblastic cells, Staphylococcus aureus and chitosan-immobilized titanium implants in a post-operative co-culture system: An in vitro study.

    PubMed

    Ghimire, Niranjan; Foss, Berit L; Sun, Yuyu; Deng, Ying

    2015-10-21

    Biomaterial-related infections (BRIs) have become a major challenge in the field of orthopedic implants. In this study, we delved into the problem of BRI and attempted to reduce the possibility of BRI incidence via surface modification of titanium (Ti) with chitosan (SA-CS-Ti). To comprehensively evaluate the anti-infection potential of SA-CS-Ti, we first constructed a post-operative infection (POI) model with varying concentrations of bacteria (10(2) CFU/sample and 10(4) CFU/sample) and a constant number of SaOS-2 cells (10(5) /sample). Then, we biologically characterized the interactions between the SaOS-2 cells, bacteria, and different Ti implants using the POI model. The results from the osteoblastic cell and bacterial attachment tests demonstrated that the SA-CS-Ti surfaces exhibit superior osteogenic behavior relative to other Ti surfaces studied while showing significant anti-infective activities in the POI model with a low infection ratio (bacteria: cell ratio of 0.001:1) 30 minutes after infection. Additionally, the SA-CS-Ti surfaces showed significantly reduced (p<0.05) bacteria proliferation compared to the control Ti surfaces (UN-Ti), demonstrating their anti-fouling property. The significantly increased (p<0.05) sensitivity of S. aureus adhered to the SA-CS-Ti surfaces against cefazolin (1 mg/L treatment) and gentamicin (10 mg/L and 100 mg/L treatment) in the co-culture system augmented potential of SA-CS-Ti to be used as orthopedic implants. This article is protected by copyright. All rights reserved.

  8. Immobilization of the α-amylase of Bacillus amyloliquifaciens TSWK1-1 for the improved biocatalytic properties and solvent tolerance.

    PubMed

    Kikani, B A; Pandey, S; Singh, S P

    2013-05-01

    The α-amylase of Bacillus amyloliquifaciens TSWK1-1 (GenBank Number, GQ121033) was immobilized by various methods, including ionic binding with DEAE cellulose, covalent coupling with gelatin and entrapment in polyacrylamide and agar. The immobilization of the purified enzyme was most effective with the DEAE cellulose followed by gelatin, agar and polyacrylamide. The K m increased, while V max decreased upon immobilization on various supports. The temperature and pH profiles broadened, while thermostability and pH stability enhanced after immobilization. The immobilized enzyme exhibited greater activity in various non-ionic surfactants, such as Tween-20, Tween-80 and Triton X-100 and ionic surfactant, SDS. Similarly, the enhanced stability of the immobilized α-amylase in various organic solvents was among the attractive features of the study. The reusability of the immobilized enzyme in terms of operational stability was assessed. The DEAE cellulose immobilized α-amylase retained its initial activity even after 20 consequent cycles. The DEAE cellulose immobilized enzyme hydrolyzed starch with 27 % of efficiency. In summary, the immobilization of B. amyloliquifaciens TSWK1-1 α-amylase with DEAE cellulose appeared most suitable for the improved biocatalytic properties and stability.

  9. Studies with an immobilized metal affinity chromatography cassette system involving binuclear triazacyclononane-derived ligands: automation of batch adsorption measurements with tagged recombinant proteins.

    PubMed

    Petzold, Martin; Coghlan, Campbell J; Hearn, Milton T W

    2014-07-18

    This study describes the determination of the adsorption isotherms and binding kinetics of tagged recombinant proteins using a recently developed IMAC cassette system and employing automated robotic liquid handling procedures for IMAC resin screening. These results confirm that these new IMAC resins, generated from a variety of different metal-charged binuclear 1,4,7-triaza-cyclononane (tacn) ligands, interact with recombinant proteins containing a novel N-terminal metal binding tag, NT1A, with static binding capacities similar to those obtained with conventional hexa-His tagged proteins, but with significantly increased association constants. In addition, higher kinetic binding rates were observed with these new IMAC systems, an attribute that can be positively exploited to increase process productivity. The results from this investigation demonstrate that enhancements in binding capacities and affinities were achieved with these new IMAC resins and chosen NT1A tagged protein. Further, differences in the binding performances of the bis(tacn) xylenyl-bridged ligands were consistent with the distance between the metal binding centres of the two tacn moieties, the flexibility of the ligand and the potential contribution from the aromatic ring of the xylenyl group to undergo π/π stacking interactions with the tagged proteins.

  10. Structure-activity relationships on the study of β-galactosidase folding/unfolding due to interactions with immobilization additives: Triton X-100 and ethanol.

    PubMed

    Soto, Dayana; Escobar, Sindy; Guzmán, Fanny; Cárdenas, Constanza; Bernal, Claudia; Mesa, Monica

    2017-03-01

    Improving the enzyme stability is a challenge for allowing their practical application. The surfactants are stabilizing agents, however, there are still questions about their influence on enzyme properties. The structure-activity/stability relationship for β-galactosidase from Bacillus circulans is studied here by Circular Dichroism and activity measurements, as a function of temperature and pH. The tendency of preserving the β-sheet and α-helix structures at temperatures below 65°C and different pH is the result of the balance between the large- and short-range effects, respecting to the active site. This information is fundamental for explaining the structural changes of this enzyme in the presence of Triton X-100 surfactant and ethanol. The enzyme thermal stabilization in the presence of this surfactant responds to the rearrangement of the secondary structure for having optimal activity/stability. The effect of ethanol is more related with changes in the dielectric properties of the aqueous solution than with protein structural transformations. These results contribute to understand the effects of surfactant-enzyme interactions on the enzyme behavior, from the structural point of view and to rationalize the surfactant-based stabilizing strategies for β-galactosidades.

  11. Ellipsometric studies on deposition of complement from human serum to IgG and IgA immobilized on hydrophobic silicon

    NASA Astrophysics Data System (ADS)

    Tengvall, Pentti; Askendal, Agneta; Lundstroem, Ingemar

    1999-01-01

    Human immunoglobulin G (IgG) and colostrum immunoglobulin A (IgA) were absorbed to hydrophobic silicon and the deposition of complement (C) was studied by ellipsometry- antibody techniques after incubation at 37 degree(s)C in human serum for up to 1 hour. In parallel experiments soluble iC3b, C4d and Bb were detected by ELISA-techniques. IgG coated surfaces rapidly activated the classical pathway and caused deposition of anti-C3c, antiproperdin, and during short serum incubation times also of anti-C1q and anti-IgG. The IgA-coated surfaces activated the alternative pathway and displayed a lag phase in the complement protein deposition. Anti-IgG, Clq, -C4, -factor H and -factor B were not deposited into IgA-surfaces at any time. Ellipsometry and antibody techniques offer a convenient and rapid means to display activation of the complement system by solid light-reflecting surfaces and facilitate a time-resolved determination of the activation pathway(s).

  12. Immobilized cell technologies for the dairy industry.

    PubMed

    Champagne, C P; Lacroix, C; Sodini-Gallot, I

    1994-01-01

    The potential applications of immobilized cell technology (ICT) to the dairy industry are examined. Immobilization modifies the physiology of cells, and the consequences of ICT on lactose as well as citrate metabolism are reviewed. Immobilization also affects the sensitivity of lactic acid bacteria (LAB) to salt and penicillin. ICT can be used to produce starters for the dairy industry, and aspects of biomass production in beads, continuous cell release from beads, and continuous fermentations with filtration cell recycle are examined. Potential applications of ICT to the dairy industry include acidification of raw milk prior to ultrafiltration, inhibition of psychrotrophic bacteria in raw milk, yogurt production, cheese manufacture, and cream fermentations. Impacts of yeast, bacterial, or bacteriophage contaminations in ICT processes as well as their control are discussed.

  13. Coupled reactions of immobilized enzymes and immobilized substrates: clinical application as exemplified by amylase assay.

    PubMed

    Barabino, R C; Gray, D N; Keyes, M H

    1978-08-01

    We described a partitioned enzyme-sensor system, which incorporates an immoblized substrate and three or more discrete immobilized enzymes. This instrument measures alpha-amylase activity by passing the solution containing alpha-amylase over a column packed with immobilized starch. The resulting oligosaccharides are successively exposed to a column or columns containing immobolized glucose oxidase, catalase, glucoamylase or maltase, and glucose oxidase. The resulting hydrogen peroxide is detected by a three-electrode amperometric cell. All immobilized reagents were immobilized on a particulate, porous alumina to allow rapid and constant flow rate. With use of less than optimum immobilized reagents, alpha-amylase activity has been measured from about 5 to 200 kU/liter with a 50 microliter sample size. Lack of sensitivity is predominantly attributable to the low activity and low stability of immobilized maltase and glucoamylase. We believe that a clinical test using this system is feasible and desirable because the immobilized reagent system should allow for testing of alpha-amylase with excellent precision, convenience to the operator, and low cost.

  14. Combined of ultrasound irradiation with high hydrostatic pressure (US/HHP) as a new method to improve immobilization of dextranase onto alginate gel.

    PubMed

    Bashari, Mohanad; Abbas, Shabbar; Xu, Xueming; Jin, Zhengyu

    2014-07-01

    In this research work, dextranase was immobilized onto calcium alginate beads by the combination of ultrasonic irradiation and high hydrostatic pressure (US/HHP) treatments. Effects of US/HHP treatments on loading efficiency and immobilization yield of dextranase enzyme onto calcium alginate beads were investigated. Furthermore, the activities of immobilized enzymes prepared with and without US/HHP treatments and that prepared with ultrasonic irradiation (US) and high hydrostatic pressure (HHP), as a function of pH, temperature, recyclability and enzyme kinetic parameters, were compared with that for free enzyme. The maximum loading efficiency and the immobilization yield were observed when the immobilized dextranase was prepared with US (40 W at 25 kHz for 15 min) combined with HHP (400 MPa for 15 min), under which the loading efficiency and the immobilization yield increased by 88.92% and 80.86%, respectively, compared to immobilized enzymes prepared without US/HHP treatment. On the other hand, immobilized enzyme prepared with US/HHP treatment showed Vmax, KM, catalytic and specificity constants values higher than that for the immobilized enzyme prepared with HHP treatment, indicated that, this new US/HHP method improved the catalytic kinetics activity of immobilized dextranase at all the reaction conditions studied. Compared to immobilized enzyme prepared either with US or HHP, the immobilized enzymes prepared with US/HHP method exhibited a higher: pH optimum, optimal reaction temperature, thermal stability and recyclability, and lower activation energy, which, illustrating the effectiveness of the US/HHP method. These results indicated that, the combination of US and HHP treatments could be an effective method for improving the immobilization of enzymes in polymers.

  15. Green biosynthesis of floxuridine by immobilized microorganisms.

    PubMed

    Rivero, Cintia W; Britos, Claudia N; Lozano, Mario E; Sinisterra, Jose V; Trelles, Jorge A

    2012-06-01

    This work describes an efficient, simple, and green bioprocess for obtaining 5-halogenated pyrimidine nucleosides from thymidine by transglycosylation using whole cells. Biosynthesis of 5-fluoro-2'-deoxyuridine (floxuridine) was achieved by free and immobilized Aeromonas salmonicida ATCC 27013 with an 80% and 65% conversion occurring in 1 h, respectively. The immobilized biocatalyst was stable for more than 4 months in storage conditions (4 °C) and could be reused at least 30 times without loss of its activity. This microorganism was able to biosynthesize 2.0 mg L(-1) min(-1) (60%) of 5-chloro-2'-deoxyuridine in 3 h. These halogenated pyrimidine 2'-deoxynucleosides are used as antitumoral agents.

  16. Plutonium Immobilization Can Loading Conceptual Design

    SciTech Connect

    Kriikku, E.

    1999-05-13

    'The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses the Plutonium Immobilization can loading conceptual design and includes a process block diagram, process description, preliminary equipment specifications, and several can loading issues. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.'

  17. Immobilization of L-arabinitol dehydrogenase on aldehyde-functionalized silicon oxide nanoparticles for L-xylulose production.

    PubMed

    Singh, Raushan Kumar; Tiwari, Manish Kumar; Singh, Ranjitha; Haw, Jung-Rim; Lee, Jung-Kul

    2014-02-01

    L-Xylulose is a potential starting material for therapeutics. However, its translation into clinical practice has been hampered by its inherently low bioavailability. In addition, the high cost associated with the production of L-xylulose is a major factor hindering its rapid deployment beyond the laboratory. In the current study, L-arabinitol 4-dehydrogenase from Hypocrea jecorina (HjLAD), which catalyzes the conversion of L-arabinitol into L-xylulose, was immobilized onto various carriers, and the immobilized enzymes were characterized. HjLAD covalently immobilized onto silicon oxide nanoparticles showed the highest immobilization efficiency (94.7 %). This report presents a comparative characterization of free and immobilized HjLAD, including its thermostability and kinetic parameters. The thermostability of HjLAD immobilized on silicon oxide nanoparticles was more than 14.2-fold higher than free HjLAD; the t1/2 of HjLAD at 25 °C was enhanced from 190 min (free) to 45 h (immobilized). In addition, the immobilized HjLAD retained 94 % of its initial activity after 10 cycles. When the immobilized HjLAD was used to catalyze the biotransformation of L-arabinitol to L-xylulose, 66 % conversion and a productivity of 7.9 g · h(-1) · L(-1) were achieved. The enhanced thermostability and reusability of HjLAD suggest that immobilization of HjLAD onto silicon oxide nanoparticles has the potential for use in the industrial production of rare sugars.

  18. The building of free-form customized immobilizers.

    PubMed

    Buscher, M

    1990-03-01

    Unusual immobilization problems occur in radiation therapy. A solution using styrofoam sheet and blocks, mylar sheet and urethane foaming chemicals is suggested here. The technique is extremely versatile and produces a light weight and reliable immobilizer.

  19. Immobilization of Mn(II) via Homogeneous and Heterogeneous Oxidation

    NASA Astrophysics Data System (ADS)

    Kang, N.; Jeong, H. Y.; Park, M.; Kim, K. H.; Lee, S.; Choi, H. J.

    2015-12-01

    This study investigated the immobilization of Mn(II) via homogeneous and heterogeneous oxidation by air. A series of kinetic experiments were performed with stirred batch reactors equipped with air spargers. The reactions were initiated by adding Mn(II) stock solutions to pH-buffered solutions amended with dissolved Fe(II), Fe oxyhydroxides, or Mn oxides. Under experimental conditions, the homogeneous oxidation of Mn(II) itself was minimal over pH 6.5-8.5. However, when dissolved Fe(II) was present, the immobilization of Mn occurred, with the extent becoming greater at higher pH. By Mn-K edge XAS analysis, the Mn removal at pH 6.5 was due to the oxidation of labile Mn(II) into insoluble Mn(III) solids, which was catalyzed by the homogeneous oxidation of Fe(II). On the other hand, Mn(II) at pH 7.0-8.5 remained largely unoxidized; instead, it was immobilized by forming co-precipitates with Fe(III) oxyhydroxides. Goethite, HFO, Mn2O3, and MnO2 were added to mediate the heterogeneous oxidation of Mn(II). In the presence of goethite and HFO, dissolved Mn was initially quickly decreased, and later gradually decreased. In both batches, the initial removal was due to the surface complexation of Mn(II) with Fe oxyhydroxides. On the other hand, the later removal in goethite-amend batches resulted from the formation of co-precipitates with Fe(III) oxyhydroxides, whereas the later removal in HFO-amended batches was due to the heterogeneous oxidation of Mn(II) into Mn(III) solids. When Mn2O3 and MnO2 were used as heterogeneous catalysts, XAS analysis did not provide mechanistic insight into Mn removal. Nonetheless, Mn2O3 was found to immobilize Mn(II) under oxic conditions. Notably, MnO2 was far more effectively immobilize Mn(II) under both oxic and anoxic conditions, pointing to its superior oxidative capability. Acknowledgement: Financial support was provided by "R&D Project on Environmental Management of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003).

  20. Validation of new bite block-type head-immobilization devices for radiotherapy in dogs.

    PubMed

    Maruo, Takuya; Nakamura, Shiori; Fukuyama, Yasuhiro; Kawarai, Shinpei

    2013-01-01

    An ideal head-immobilization method provides a high level of accuracy and reproducibility in the immobilization. Various head-immobilization methods for radiotherapy have been published and are excellent in terms of accuracy; however, these methods are complicated to use, and labor intensive. The present study describes two new bite block-type head-immobilization devices designed for higher stability and lower vertical variation. The device designed in our previous study (the bite block-type head-immobilization device; Device A) was modified by making a groove on the top the horizontal plate (Device B) for a stable ventral-dorsal position, or beneath the horizontal plate (Device C) for a stable dorsal-ventral position. The three devices were objectively compared with respect to setup time, and accuracy of the computed tomography scan images by two authors independently. Five male healthy beagles were used in this study. For each device, the setup time and the variation in the coordinates were measured five times for each dog. The mean setup times for Devices A, B, and C were 3.3, 1.5, and 2.4 min, respectively, showing the groove modifications were able to reduce the setup time (in device B, by at least 50%). Moreover, three-dimensional analysis of the computed tomography images revealed that the measurement variability of Device A (1.6 ± 1.0 mm) was significantly higher than that of Device C (0.7 ± 0.4 mm; P < 0.001). Collectively, our results show that use of a bite block-type head-immobilization device with a groove improves the setup time and head-immobilization accuracy.

  1. Immobilized acclimated biomass-powdered activated carbon for the bioregeneration of granular activated carbon loaded with phenol and o-cresol.

    PubMed

    Toh, Run-Hong; Lim, Poh-Eng; Seng, Chye-Eng; Adnan, Rohana

    2013-09-01

    The objectives of the study are to use immobilized acclimated biomass and immobilized biomass-powdered activated carbon (PAC) as a novel approach in the bioregeneration of granular activated carbon (GAC) loaded with phenol and o-cresol, respectively, and to compare the efficiency and rate of the bioregeneration of the phenolic compound-loaded GAC using immobilized and suspended biomasses under varying GAC dosages. Bioregeneration of GAC loaded with phenol and o-cresol, respectively, was conducted in batch system using the sequential adsorption and biodegradation approach. The results showed that the bioregeneration efficiency of GAC loaded with phenol or o-cresol was basically the same irrespective of whether the immobilized or suspended biomass was used. Nonetheless, the duration for bioregeneration was longer under immobilized biomass. The beneficial effect of immobilized PAC-biomass for bioregeneration is the enhancement of the removal rate of the phenolic compounds via adsorption and the shortening of the bioregeneration duration.

  2. Short-Term Limb Immobilization Affects Cognitive Motor Processes

    ERIC Educational Resources Information Center

    Toussaint, Lucette; Meugnot, Aurore

    2013-01-01

    We examined the effects of a brief period of limb immobilization on the cognitive level of action control. A splint placed on the participants' left hand was used as a means of immobilization. We used a hand mental rotation task to investigate the immobilization-induced effects on motor imagery performance (Experiments 1 and 2) and a number mental…

  3. Metal immobilization in soils using synthetic zeolites.

    PubMed

    Oste, Leonard A; Lexmond, Theo M; Van Riemsdijk, Willem H

    2002-01-01

    In situ immobilization of heavy metals in contaminated soils is a technique to improve soil quality. Synthetic zeolites are potentially useful additives to bind heavy metals. This study selected the most effective zeolite in cadmium and zinc binding out of six synthetic zeolites (mordenite-type, faujasite-type, zeolite X, zeolite P, and two zeolites A) and one natural zeolite (clinoptilolite). Zeolite A appeared to have the highest binding capacity between pH 5 and 6.5 and was stable above pH 5.5. The second objective of this study was to investigate the effects of zeolite addition on the dissolved organic matter (DOM) concentration. Since zeolites increase soil pH and bind Ca, their application might lead to dispersion of organic matter. In a batch experiment, the DOM concentration increased by a factor of 5 when the pH increased from 6 to 8 as a result of zeolite A addition. A strong increase in DOM was also found in the leachate of soil columns, particularly in the beginning of the experiment. This resulted in higher metal leaching caused by metal-DOM complexes. In contrast, the free ionic concentration of Cd and Zn strongly decreased after the addition of zeolites, which might explain the reduction in metal uptake observed in plant growth experiments. Pretreatment of zeolites with acid (to prevent a pH increase) or Ca (to coagulate organic matter) suppressed the dispersion of organic matter, but also decreased the metal binding capacity of the zeolites due to competition of protons or Ca.

  4. Enzyme Engineering for In Situ Immobilization.

    PubMed

    Rehm, Fabian B H; Chen, Shuxiong; Rehm, Bernd H A

    2016-10-14

    Enzymes are used as biocatalysts in a vast range of industrial applications. Immobilization of enzymes to solid supports or their self-assembly into insoluble particles enhances their applicability by strongly improving properties such as stability in changing environments, re-usability and applicability in continuous biocatalytic processes. The possibility of co-immobilizing various functionally related enzymes involved in multistep synthesis, conversion or degradation reactions enables the design of multifunctional biocatalyst with enhanced performance compared to their soluble counterparts. This review provides a brief overview of up-to-date in vitro immobilization strategies while focusing on recent advances in enzyme engineering towards in situ self-assembly into insoluble particles. In situ self-assembly approaches include the bioengineering of bacteria to abundantly form enzymatically active inclusion bodies such as enzyme inclusions or enzyme-coated polyhydroxyalkanoate granules. These one-step production strategies for immobilized enzymes avoid prefabrication of the carrier as well as chemical cross-linking or attachment to a support material while the controlled oriented display strongly enhances the fraction of accessible catalytic sites and hence functional enzymes.

  5. Immobilization of invertase on krill chitin

    SciTech Connect

    Synowiecki, J.; Sikorski, Z.E.; Naczk, M.

    1981-01-01

    By simple adsorption or covalent binding, enzymes were immobilized on chitin isolated from the shells of edible shellfish. It is reported that the best results were obtained by immoblizing diastase on krill chitin by adsorption at pH 6.7 and an ionic strength of 0.05.

  6. Immobilization of Enzymes in Polymer Supports.

    ERIC Educational Resources Information Center

    Conlon, Hugh D.; Walt, David R.

    1986-01-01

    Two experiments in which an enzyme is immobilized onto a polymeric support are described. The experiments (which also demonstrate two different polymer preparations) involve: (1) entrapping an enzyme in an acrylamide polymer; and (2) reacting the amino groups on the enzyme's (esterase) lysine residues with an activated polymer. (JN)

  7. Sand transport over an immobile gravel substrate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted in a laboratory flume channel to evaluate the effects of increasing amounts of sand with an immobile gravel fraction on the sand transport rate and configuration of the sand bed. Knowledge of the movement of sand in gravel beds is important for the management of streams a...

  8. Plutonium Immobilization Can Loading Preliminary Specifications

    SciTech Connect

    Kriikku, E.

    1998-11-25

    This report discusses the Plutonium Immobilization can loading preliminary equipment specifications and includes a process block diagram, process description, equipment list, preliminary equipment specifications, plan and elevation sketches, and some commercial catalogs. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.

  9. Immobilization: A Revolution in Traditional Brewing

    NASA Astrophysics Data System (ADS)

    Virkajärvi, Ilkka; Linko, Matti

    In nature many micro-organisms tend to bind to solid surfaces. This tendency has long been utilized in a number of processes, for example in producing vinegar and acetic acid in bioreactors filled with wood shavings. Acetobacteria are attached to the surface of these shavings. In modern technical language: they are immobilized. Also yeast cells can be immobilized. In the brewing industry this has been the basis for maintaining efficient, continuous fermentation in bioreactors with very high yeast concentrations. The most dramatic change in brewing over recent years has been the replacement of traditional lagering of several weeks by a continuous process in which the residence time is only about 2h. Continuous primary fermentation is used on a commercial scale in New Zealand. In this process, instead of a carrier, yeast is retained in reactors by returning it partly after separation. In many pilot scale experiments the primary fermentation is shortened from about 1week to 1-2days using immobilized yeast reactors. When using certain genetically modified yeast strains no secondary fermentation is needed, and the total fermentation time in immobilized yeast reactors can therefore be shortened to only 2days.

  10. Immobilization of antibacterial chlorhexidine on stainless steel using crosslinking polydopamine film: Towards infection resistant medical devices.

    PubMed

    Mohd Daud, Nurizzati; Saeful Bahri, Ihda Fithriyana; Nik Malek, Nik Ahmad Nizam; Hermawan, Hendra; Saidin, Syafiqah

    2016-09-01

    Chlorhexidine (CHX) is known for its high antibacterial substantivity and is suitable for use to bio-inert medical devices due to its long-term antibacterial efficacy. However, CHX molecules require a crosslinking film to be stably immobilized on bio-inert metal surfaces. Therefore, polydopamine (PDA) was utilized in this study to immobilize CHX on the surface of 316L type stainless steel (SS316L). The SS316L disks were pre-treated, modified with PDA film and immobilized with different concentrations of CHX (10mM-50mM). The disks were then subjected to various surface characterization analyses (ATR-FTIR, XPS, ToF-SIMS, SEM and contact angle measurement) and tested for their cytocompatibility with human skin fibroblast (HSF) cells and antibacterial activity against Escherichia coli and Staphylococcus aureus. The results demonstrated the formation of a thin PDA film on the SS316L surface, which acted as a crosslinking medium between the metal and CHX. CHX was immobilized via a reduction process that covalently linked the CHX molecules with the functional group of PDA. The immobilization of CHX increased the hydrophobicity of the disk surfaces. Despite this property, a low concentration of CHX optimized the viability of HSF cells without disrupting the morphology of adherent cells. The immobilized disks also demonstrated high antibacterial efficacy against both bacteria, even at a low concentration of CHX. This study demonstrates a strong beneficial effect of the crosslinked PDA film in immobilizing CHX on bio-inert metal, and these materials are applicable in medical devices. Specifically, the coating will restrain bacterial proliferation without suffocating nearby tissues.

  11. Covalent immobilization of glucose oxidase onto new modified acrylonitrile copolymer/silica gel hybrid supports.

    PubMed

    Godjevargova, Tzonka; Nenkova, Ruska; Dimova, Nedyalka

    2005-08-12

    New polymer/silica gel hybrid supports were prepared by coating high surface area of silica gel with modified acrylonitrile copolymer. The concentrations of the modifying agent (NaOH) and the modified polymer were varied. GOD was covalently immobilized on these hybrid supports and the relative activity and the amount of bound protein were determined. The highest relative activity and sufficient amount of bound protein of the immobilized GOD were achieved in 10% NaOH and 2% solution of modified acrylonitrile copolymer. The influence of glutaraldehyde concentration and the storage time on enzyme efficiency were examined. Glutaraldehyde concentration of 0.5% is optimal for the immobilized GOD. It was shown that the covalently bound enzyme (using 0.5% glutaraldehyde) had higher relative activity than the activity of the adsorbed enzyme. Covalently immobilized GOD with 0.5% glutaraldehyde was more stable for four months in comparison with the one immobilized on pure silica gel, hybrid support with 10% glutaraldehyde and the free enzyme. The effect of the pore size on the enzyme efficiency was studied on four types of silica gel with different pore size. Silica with large pores (CPC-Silica carrier, 375 A) presented higher relative activity than those with smaller pore size (Silica gel with 4, 40 and 100 A). The amount of bound protein was also reduced with decreasing the pore size. The effect of particle size was studied and it was found out that the smaller the particle size was, the greater the activity and the amount of immobilized enzyme were. The obtained results proved that these new polymer/silica gel hybrid supports were suitable for GOD immobilization.

  12. Evaluation of p-cresol degradation with polyphenol oxidase (PPO) immobilized in various matrices.

    PubMed

    Edalli, Vijayalakshmi A; Mulla, Sikandar I; Eqani, Syed Ali Musstjab Akber Shah; Mahadevan, Gurumurthy D; Sharma, Rohit; Shouche, Yogesh; Kamanavalli, Chandrappa M

    2016-12-01

    p-Cresol is an environmental pollutant due to its vast use, toxicity and persistence, nevertheless, its degradation in an enzyme is unclear. In this study, we used Pleurotus sp. isolate VLECK02 polyphenol oxidase (PPO) for the determination of p-cresol degradation. On the basis of UV, FT-IR and chromatographic (HPLC and GC-MS) analysis, 4-methylcatechol was identified as the main metabolite of p-cresol catabolism. In addition, batch and semi-continuous degradation of p-cresol (10 and 20 mM) were studied and compared by free and immobilized PPO in different matrices like sodium alginate (SA), sodium alginate-polyvinyl alcohol (SA-PVA) and sodium alginate-polyvinyl alcohol-silver nanoparticles (SA-PVA-AgNPs). The experimental data showed that an enzyme (PPO) immobilized in SA-PVA-AgNPs was completely degraded p-cresol at initial concentrations of 10 and 20 mM within 30 h. These results suggest that the enzyme immobilized in SA-PVA-AgNPs has achieved higher degradation rates at a given time than free PPO and PPO immobilized in SA-PVA and SA. The SA-PVA-AgNPs and SA-PVA immobilized enzyme could be reused for more than 12 and 8 cycles, respectively, without losing any degradation capacity. Moreover, the immobilized PPO showed higher tolerance to various temperatures and pH than free PPO. Hence, immobilized PPO could be useful for the bioremediation of environment contaminated with phenolic compounds like p-cresol.

  13. TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

    PubMed

    Ispirli Doğaç, Yasemin; Deveci, Ilyas; Teke, Mustafa; Mercimek, Bedrettin

    2014-09-01

    The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity.

  14. Optimizing immobilized enzyme performance in cell-free environments to produce liquid fuels.

    SciTech Connect

    Kumar, Sanat

    2015-02-05

    The overall goal of this project was to optimize enzyme performance for the production of bio-diesel fuel. Enzyme immobilization has attracted much attention as a means to increase productivity. Mesorporous silica materials have been known to be best suited for immobilizing enzymes. A major challenge is to ensure that the enzymatic activity is retained after immobilization. Two major factors which drive enzymatic deactivation are protein-surface and inter-protein interactions. Previously, we studied protein stability inside pores and how to optimize protein-surface interactions to minimize protein denaturation. In this work we studied eh effect of surface curvature and chemistry on inter-protein interactions. Our goal was to find suitable immobilization supports which minimize these inter-protein interactions. Our studies carried out in the frame work of Hydrophobic-Polar (HP) model showed that enzymes immobilized inside hydrophobic pores of optimal sizes are best suited to minimize these inter-protein interactions. Besides, this study is also of biological importance to understand the role of chaperonins in protein disaggregation. Both of these aspects profited immensely with collaborations with our experimental colleague, Prof. Georges Belfort (RPI), who performed the experimental analog of our theoretical works.

  15. Effects of RGD immobilization on light-induced cell sheet detachment from TiO2 nanodots films.

    PubMed

    Cheng, Kui; Wang, Tiantian; Yu, Mengliu; Wan, Hongping; Lin, Jun; Weng, Wenjian; Wang, Huiming

    2016-06-01

    Light-induced cell detachment is reported to be a safe and effective cell sheet harvest method. In the present study, the effects of arginine-glycine-aspartic acid (RGD) immobilization on cell growth, cell sheet construction and cell harvest through light illumination are investigated. RGD was first immobilized on TiO2 nanodots films through simple physical adsorption, and then mouse pre-osteoblastic MC3T3-E1 cells were seeded on the films. It was found that RGD immobilization promoted cell adhesion and proliferation. It was also observed that cells cultured on RGD immobilized films showed relatively high level of pan-cadherin. Cells harvested with ultraviolet illumination (365 nm) showed good viability on both RGD immobilized and unmodified TiO2 nanodot films. Single cell detachment assay showed that cells detached more quickly on RGD immobilized TiO2 nanodot films. That could be ascribed to the RGD release after UV365 illumination. The current study demonstrated that RGD immobilization could effectively improve both the cellular responses and light-induced cell harvest.

  16. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    PubMed

    Wang, Chanchan; Sauvageau, Dominic; Elias, Anastasia

    2016-01-20

    A rapid, efficient technique for the attachment of bacteriophages (phages) onto polyhydroxyalkanoate (PHA) surfaces has been developed and compared to three reported methods for phage immobilization. Polymer surfaces were modified to facilitate phage attachment using (1) plasma treatment alone, (2) plasma treatment followed by activation by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS), (3) plasma-initiated acrylic acid grafting, or (4) plasma-initiated acrylic acid grafting with activation by EDC and sulfo-NHS. The impact of each method on the surface chemistry of PHA was investigated using contact angle analysis and X-ray photoelectron spectroscopy. Each of the four treatments was shown to result in both increased hydrophilicity and in the modification of the surface functional groups. Modified surfaces were immersed in suspensions of phage T4 for immobilization. The highest level of phage binding was observed for the surfaces modified by plasma treatment alone. The change in chemical bond states observed for surfaces that underwent plasma treatment is suspected to be the cause of the increased binding of active phages. Plasma-treated surfaces were further analyzed through phage-staining and fluorescence microscopy to assess the surface density of immobilized phages and their capacity to capture hosts. The infective capability of attached phages was confirmed by exposing the phage-immobilized surfaces to the host bacteria Escherichia coli in both plaque and infection dynamic assays. Plasma-treated surfaces with immobilized phages displayed higher infectivity than surfaces treated with other methods; in fact, the equivalent initial multiplicity of infection was 2 orders of magnitude greater than with other methods. Control samples - prepared by immersing polymer surfaces in phage suspensions (without prior plasma treatment) - did not show any bacterial growth inhibition, suggesting they did not bind

  17. Antibody immobilization using pneumatic spray: comparison with the avidin-biotin bridge immobilization method.

    PubMed

    Figueroa, Jhon; Magaña, Sonia; Lim, Daniel V; Schlaf, Rudy

    2012-12-14

    The formation of a thin antibody film on a glass surface using pneumatic spray was investigated as a potential immobilization technique for capturing pathogenic targets. Goat-Escherichia coli O157:H7 IgG films were made by pneumatic spray and compared against the avidin-biotin bridge immobilized films by assaying with green fluorescent protein (GFP) transformed E. coli O157:H7 cells and fluorescent reporter antibodies. Functionality, stability, and immobilization of the films were tested. The pneumatic spray films had lower fluorescence intensity values than the avidin-biotin bridge films but resulted in similar detection for E. coli O157:H7 at 10(5)-10(7)cells/ml sample concentrations with no detection of non-E. coli O157:H7 strains. Both methods also resulted in similar percent capture efficiencies. The results demonstrated that immobilization of antibody via pneumatic spray did not render the antibody non-functional and produced stable antibody films. The amount of time necessary for immobilization of the antibody was reduced significantly from 24h for the avidin-biotin bridge to 7 min using the pneumatic spray technique, with additional benefits of greatly reduced use of materials and chemicals. The pneumatic spray technique promises to be an alternative for the immobilization of antibodies on glass slides for capturing pathogenic targets and use in biosensor type devices.

  18. Enhancement of Peroxidase Stability Against Oxidative Self-Inactivation by Co-immobilization with a Redox-Active Protein in Mesoporous Silicon and Silica Microparticles.

    PubMed

    Sahare, P; Ayala, M; Vazquez-Duhalt, R; Pal, U; Loni, A; Canham, L T; Osorio, I; Agarwal, V

    2016-12-01

    The study of the stability enhancement of a peroxidase immobilized onto mesoporous silicon/silica microparticles is presented. Peroxidases tend to get inactivated in the presence of hydrogen peroxide, their essential co-substrate, following an auto-inactivation mechanism. In order to minimize this inactivation, a second protein was co-immobilized to act as an electron acceptor and thus increase the stability against self-oxidation of peroxidase. Two heme proteins were immobilized into the microparticles: a fungal commercial peroxidase and cytochrome c from equine heart. Two types of biocatalysts were prepared: one with only covalently immobilized peroxidase (one-protein system) and another based on covalent co-immobilization of peroxidase and cytochrome c (two-protein system), both immobilized by using carbodiimide chemistry. The amount of immobilized protein was estimated spectrophotometrically, and the characterization of the biocatalyst support matrix was performed using Brunauer-Emmett-Teller (BET), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared (FTIR) analyses. Stability studies show that co-immobilization with the two-protein system enhances the oxidative stability of peroxidase almost four times with respect to the one-protein system. Thermal stability analysis shows that the immobilization of peroxidase in derivatized porous silicon microparticles does not protect the protein from thermal denaturation, whereas biogenic silica microparticles confer significant thermal stabilization.

  19. Impact of Solvent pH on Direct Immobilization of Lysosome-Related Cell Organelle Extracts on TiO₂ for Melanin Treatment.

    PubMed

    Bang, Seung Hyuck; Kim, Pil; Oh, Suk-Jung; Kim, Yang-Hoon; Min, Jiho

    2015-05-01

    Techniques for immobilizing effective enzymes on nanoparticles for stabilization of the activity of free enzymes have been developing as a pharmaceutical field. In this study, we examined the effect of three different pH conditions of phosphate buffer, as a dissolving solvent for lysosomal enzymes, on the direct immobilization of lysosomal enzymes extracted from Hen's egg white and Saccharomyces cerevisiae. Titanium(IV) oxide (TiO2) nanoparticles, which are extensively used in many research fields, were used in this study. The lysosomal enzymes immobilized on TiO2 under each pH condition were evaluated to maintain the specific activity of lysosomal enzymes, so that we can determine the degree of melanin treatment in lysosomal enzymes immobilized on TiO2. We found that the immobilization efficiency and melanin treatment activity in both lysosomal enzymes extracted from Hen's egg white and S. cerevisiae were the highest in an acidic condition of phosphate buffer (pH 4). However, the immobilization efficiency and melanin treatment activity were inversely proportional to the increase in pH under alkaline conditions. In addition, enhanced immobilization efficiency was shown in TiO2 pretreated with a divalent, positively charged ion, Ca(2+), and the melanin treatment activity of immobilized lysosomal enzymes on TiO2 pretreated with Ca(2+) was also increased. Therefore, this result suggests that the immobilization efficiency and melanin treatment activity of lysosomal enzymes can be enhanced according to the pH conditions of the dissolving solvent.

  20. Highly efficient immobilization of beta-lactoglobulin in functionalized mesoporous nanoparticles: a simple and useful approach for enhancement of protein stability.

    PubMed

    Falahati, Mojtaba; Saboury, Ali Akbar; Shafiee, Abbas; Sorkhabadi, Seyed Mahdi Rezayat; Kachooei, Ehsan; Ma'mani, Leila; Haertlé, Thomas

    2012-05-01

    The immobilization of β-lactoglobulin-B (BLG-B) onto the amine-functionalized KIT-6 [n-PrNH(2)-KIT-6], which has average pore diameter around 6.5 nm, was studied. [n-PrNH(2)-KIT-6] proved to be highly effective agent for BLG-B adsorption. UV-visible spectroscopy studies demonstrated that the immobilized BLG-B was less prone to thermally induced aggregation than the free protein. Circular dichroism (CD) spectra of free and immobilized BLG-B were recorded and significant differences in both the backbone and aromatic regions of the spectra were observed upon thermic stress. The obtained results showed that structural elements of the immobilized BLG-B are kept strongly together, making the protein more resistant to heat denaturation. The melting temperatures of the free and immobilized BLG-B were measured by far-UV CD, which showed 19 °C higher heat resistance of the immobilized BLG-B compared with its free form. Acrylamide quenching of fluorescence of free and immobilized forms of BLG-B as a function of temperature revealed that the immobilized BLG-B was more resistant to Trp quenching. Therefore immobilization of BLG-B onto [n-PrNH(2)-KIT-6] is accompanied by favorable structural stability of BLG-B in the confined space.

  1. Enhancement of Peroxidase Stability Against Oxidative Self-Inactivation by Co-immobilization with a Redox-Active Protein in Mesoporous Silicon and Silica Microparticles

    NASA Astrophysics Data System (ADS)

    Sahare, P.; Ayala, M.; Vazquez-Duhalt, R.; Pal, U.; Loni, A.; Canham, L. T.; Osorio, I.; Agarwal, V.

    2016-09-01

    The study of the stability enhancement of a peroxidase immobilized onto mesoporous silicon/silica microparticles is presented. Peroxidases tend to get inactivated in the presence of hydrogen peroxide, their essential co-substrate, following an auto-inactivation mechanism. In order to minimize this inactivation, a second protein was co-immobilized to act as an electron acceptor and thus increase the stability against self-oxidation of peroxidase. Two heme proteins were immobilized into the microparticles: a fungal commercial peroxidase and cytochrome c from equine heart. Two types of biocatalysts were prepared: one with only covalently immobilized peroxidase (one-protein system) and another based on covalent co-immobilization of peroxidase and cytochrome c (two-protein system), both immobilized by using carbodiimide chemistry. The amount of immobilized protein was estimated spectrophotometrically, and the characterization of the biocatalyst support matrix was performed using Brunauer-Emmett-Teller (BET), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared (FTIR) analyses. Stability studies show that co-immobilization with the two-protein system enhances the oxidative stability of peroxidase almost four times with respect to the one-protein system. Thermal stability analysis shows that the immobilization of peroxidase in derivatized porous silicon microparticles does not protect the protein from thermal denaturation, whereas biogenic silica microparticles confer significant thermal stabilization.

  2. Strength of interactions between immobilized dye molecules and sol-gel matrices.

    PubMed

    Ismail, Fanya; Schoenleber, Monika; Mansour, Rolan; Bastani, Behnam; Fielden, Peter; Goddard, Nicholas J

    2011-02-21

    In this paper we present a new theory to re-examine the immobilization technique of dye doped sol-gel films, define the strength and types of possible bonds between the immobilized molecule and sol-gel glass, and show that the immobilized molecule is not free inside the pores as was previously thought. Immobilizing three different pH sensitive dyes with different size and functional groups inside the same sol-gel films revealed important information about the nature of the interaction between the doped molecule and the sol-gel matrix. The samples were characterized by means of ultraviolet-visible spectrophotometer (UV-VIS), thermal gravimetric analysis (TGA), mercury porosimetry (MP), nuclear magnetic resonance spectroscopy ((29)Si NMR) and field-emission environmental scanning electron microscopy (ESEM-FEG). It was found that the doped molecule itself has a great effect on the strength and types of the bonds. A number of factors were identified, such as number and types of the functional groups, overall charge, size, pK(a) and number of the silanol groups which surround the immobilized molecule. These results were confirmed by the successful immobilization of bromocresol green (BCG) after a completely polymerized sol-gel was made. The sol-gel consisted of 50% tetraethoxysilane (TEOS) and 50% methyltriethoxysilane (MTEOS) (w/w). Moreover, the effect of the immobilized molecule on the structure of the sol-gel was studied by means of a leaky waveguide (LW) mode for doped films made before and after polymerization of the sol-gel.

  3. The impact of immobile zones on the transport and retention of nanoparticles in porous media

    NASA Astrophysics Data System (ADS)

    Molnar, Ian L.; Gerhard, Jason I.; Willson, Clinton S.; O'Carroll, Denis M.

    2015-11-01

    Nanoparticle transport and retention within porous media is treated by conceptualizing the porous media as a series of independent collectors (e.g., Colloid Filtration Theory). This conceptualization assumes that flow phenomena near grain-grain contacts, such as immobile zones (areas of low flow), exert a negligible influence on nanoparticle transport and assumes that retention and release of particles depends only on surface chemistry. This study investigated the impact of immobile zones on nanoparticle transport and retention by employing synchrotron X-ray computed microtomography (SXCMT) to examine pore-scale silver nanoparticle distributions during transport through three sand columns: uniform iron oxide, uniform quartz, and well-graded quartz. Extended tailing was observed during the elution phase of all experiments suggesting that hydraulic retention in immobile zones, not detachment from grains, was the source of tailing. A numerical simulation of fluid flow through an SXCMT data set predicted the presence of immobile zones near grain-grain contacts. SXCMT-determined silver nanoparticle concentrations observed that significantly lower nanoparticle concentrations existed near grain-grain contacts throughout the duration of all experiments. In addition, the SXCMT-determined pore-scale concentration gradients were found to be independent of surface chemistry and grain size distribution, suggesting that immobile zones limit the diffusive transport of nanoparticles toward the collectors. These results suggest that the well-known overprediction of nanoparticle retention by traditional CFT may be due to ignoring the influences of grain-grain contacts and immobile zones. As such, accurate prediction of nanoparticle transport requires consideration of immobile zones and their influence on both hydraulic and surface retention.

  4. Mussel-inspired immobilization of vascular endothelial growth factor (VEGF) for enhanced endothelialization of vascular grafts.

    PubMed

    Shin, Young Min; Lee, Yu Bin; Kim, Seok Joo; Kang, Jae Kyeong; Park, Jong-Chul; Jang, Wonhee; Shin, Heungsoo

    2012-07-09

    Most polymeric vascular prosthetic materials have low patency rate for replacement of small diameter vessels (<5 mm), mainly due to failure to generate healthy endothelium. In this study, we present polydopamine-mediated immobilization of growth factors on the surface of polymeric materials as a versatile tool to modify surface characteristics of vascular grafts potentially for accelerated endothelialization. Polydopamine was deposited on the surface of biocompatible poly(L-lactide-co-ε-caprolactone) (PLCL) elastomer, on which vascular endothelial growth factor (VEGF) was subsequently immobilized by simple dipping. Surface characteristics and composition were investigated by using scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Immobilization of VEGF on the polydopamine-deposited PLCL films was effective (19.8 ± 0.4 and 197.4 ± 19.7 ng/cm(2) for DPv20 and DPv200 films, respectively), and biotin-mediated labeling of immobilized VEGF revealed that the fluorescence intensity increased as a function of the concentration of VEGF solution. The effect of VEGF on adhesion of HUVECs was marginal, which may have been masked by polydopamine layer that also enhanced cell adhesion. However, VEGF-immobilized substrate significantly enhanced proliferation of HUVECs for over 7 days of in vitro culture and also improved their migration. In addition, immobilized VEGF supported robust cell to cell interactions with strong expression of CD 31 marker. The same process was effective for immobilization of basic fibroblast growth factor, demonstrating the robustness of polydopamine layer for secondary ligation of growth factors as a simple and novel surface modification strategy for vascular graft materials.

  5. Immobilizer-assisted management of metal-contaminated agricultural soils for safer food production.

    PubMed

    Kim, Kwon-Rae; Kim, Jeong-Gyu; Park, Jeong-Sik; Kim, Min-Suk; Owens, Gary; Youn, Gyu-Hoon; Lee, Jin-Su

    2012-07-15

    Production of food crops on metal contaminated agricultural soils is of concern because consumers are potentially exposed to hazardous metals via dietary intake of such crops or crop derived products. Therefore, the current study was conducted to develop management protocols for crop cultivation to allow safer food production. Metal uptake, as influenced by pH change-induced immobilizing agents (dolomite, steel slag, and agricultural lime) and sorption agents (zeolite and compost), was monitored in three common plants representative of leafy (Chinese cabbage), root (spring onion) and fruit (red pepper) vegetables, in a field experiment. The efficiency of the immobilizing agents was assessed by their ability to decrease the phytoavailability of metals (Cd, Pb, and Zn). The fruit vegetable (red pepper) showed the least accumulation of Cd (0.16-0.29 mgkg(-1) DW) and Pb (0.2-0.9 mgkg(-1) DW) in edible parts regardless of treatment, indicating selection of low metal accumulating crops was a reasonable strategy for safer food production. However, safer food production was more likely to be achievable by combining crop selection with immobilizing agent amendment of soils. Among the immobilizing agents, pH change-induced immobilizers were more effective than sorption agents, showing decreases in Cd and Pb concentrations in each plant well below standard limits. The efficiency of pH change-induced immobilizers was also comparable to reductions obtained by 'clean soil cover' where the total metal concentrations of the plow layer was reduced via capping the surface with uncontaminated soil, implying that pH change-induced immobilizers can be practically applied to metal contaminated agricultural soils for safer food production.

  6. Electrostatic protein immobilization using charged polyacrylamide gels and cationic detergent microfluidic Western blotting.

    PubMed

    Kim, Dohyun; Karns, Kelly; Tia, Samuel Q; He, Mei; Herr, Amy E

    2012-03-06

    We report a novel protein immobilization matrix for fully integrated microfluidic Western blotting (WB). The electrostatic immobilization gel (EIG) enables immobilization of all proteins sized using cetyl trimethylammonium bromide polyacrylamide gel electrophoresis (CTAB-PAGE), for subsequent electrophoretic probing with detection affinity reagents (e.g., labeled antibodies). The "pan-analyte" capture strategy introduced here uses polyacrylamide gel grafted with concentrated point charges (zwitterionic macromolecules), in contrast to existing microfluidic WB strategies that rely on a sandwich immunoassay format for analyte immobilization and detection. Sandwich approaches limit analyte immobilization to capture of only a priori known targets. A charge interaction mechanism study supports the hypothesis that electrostatic interaction plays a major role in analyte immobilization on the EIG. We note that protein capture efficiency depends on both the concentration of copolymerized charges and ionic strength of the gel buffer. We demonstrate pan-analyte immobilization of sized CTAB-laden model proteins (protein G, ovalbumin, bovine serum albumin, β-galactosidase, lactoferrin) on the EIG with initial capture efficiencies ranging from 21 to 100%. Target proteins fixed on the EIG (protein G, lactoferrin) are detected using antibody probes with signal-to-noise ratios of 34 to 275. The approach advances protein immunoblotting performance through 200× reduction on sample consumption, 12× reduction in assay duration, and automated assay operation, compared to slab-gel WB. Using the microfluidic WB assay, assessment of lactoferrin in human tear fluid is demonstrated with a goal of advancing toward nonbiopsy-based diagnosis of Sjögren's Syndrome, an autoimmune disease.

  7. Engineering cholesterol-based fibers for antibody immobilization and cell capture

    NASA Astrophysics Data System (ADS)

    Cohn, Celine

    abilities of the CSS fibers were compared to that of hydrophobic polycaprolactone (PCL) fibers and hydrophilic plasma-treated PCL fibers. Electrospun CSS fibers were found to immobilize equivalent amounts of protein as hydrophobically immobilized proteins. However, these proteins captured 6 times more cells, indicative of retained protein function. The second key concept was the design and fabrication of a hybridized lipid fiber. Lipid fibers provide improved protein function but fabrication difficulties have limited their adoption. Thus, we sought to fabricate a lipid-polymer hybrid that is easily fabricated while maintaining protein function. The hybrid fiber consists of a PCL backbone with conjugated CSS. The hybrid lipid fibers showed improved protein function. In addition, higher lipid concentrations were directly correlated to higher cell capture efficiencies. The third key concept was on the development of dually functionalized lipid fibers and understanding the resulting cell capture efficiencies. Many platforms are unable to simultaneously search for heterogeneous populations of CTCs -- the ability to dually functionalize cell-capturing platforms would address this technological weakness. Studies indicated that dually functionalizing the lipid fibers did not compromise the platforms' abilities to capture the cells of interest. Such dually functionalized fibers allow for a single cell-capture platform to successfully detect heterogeneous populations of CTCs. The body of work encompassed herein describes the use of lipid fibers for antibody immobilization and cell capture. Data from various projects indicate that the use of cholesterol-based fibers produced from electrospun CSS are well suited for protein immobilization. The CSS fibers are able to immobilize equivalent amounts of protein as compared to other immobilization techniques. However, the benefit of these fibers is illustrated by the strong cell-capturing efficiencies, indicating that the immobilized

  8. Properties of cellulase immobilized on agarose gel with spacer

    SciTech Connect

    Chim-anage, P.; Kashiwagi, Y.; Magae, Y.; Ohta, T.; Sasaki, T.

    1986-12-01

    Cellulase produced by fungus Trichoderma viride was immobilized on agarose beads (Sepharose 4B) activated by cyanogen bromide and also on activated agarose beads that contained spacer arm (activated Ch-Sepharose 4B and Affi-Gel 15). The CMCase activity retained by immobilized cellulase on activated Sepharose containing the spacer tended to be higher than that immobilized without spacer, although the extent of protein immobilization was lower. Also, the higher substrate specificity for cellulase immobilized on beads with spacer was obtained for cellobiose, acid-swollen cellulose, or cellulose powder. The hydrolysis product from their substrates was mainly glucose. 10 references.

  9. in situ Calcite Precipitation for Contaminant Immobilization

    SciTech Connect

    Yoshiko Fujita; Robert W. Smith

    2009-08-01

    in situ Calcite Precipitation for Contaminant Immobilization Yoshiko Fujita (Yoshiko.fujita@inl.gov) (Idaho National Laboratory, Idaho Falls, Idaho, USA) Robert W. Smith (University of Idaho-Idaho Falls, Idaho Falls, Idaho, USA) Subsurface radionuclide and trace metal contaminants throughout the U.S. Department of Energy (DOE) complex pose one of DOE’s greatest challenges for long-term stewardship. One promising stabilization mechanism for divalent trace ions, such as the short-lived radionuclide strontium-90, is co-precipitation in calcite. Calcite, a common mineral in the arid western U.S., can form solid solutions with trace metals. The rate of trace metal incorporation is susceptible to manipulation using either abiotic or biotic means. We have previously demonstrated that increasing the calcite precipitation rate by stimulating the activity of urea hydrolyzing microorganisms can result in significantly enhanced Sr uptake. Urea hydrolysis causes the acceleration of calcium carbonate precipitation (and trace metal co-precipitation) by increasing pH and alkalinity, and also by liberating the reactive cations from the aquifer matrix via exchange reactions involving the ammonium ion derived from urea: H2NCONH2 + 3H2O ? 2NH4+ + HCO3- + OH- urea hydrolysis >X:2Ca + 2NH4+ ? 2>X:NH4 + Ca2+ ion exchange Ca2+ + HCO3- + OH- ? CaCO3(s) + H2O calcite precipitation where >X: is a cation exchange site on the aquifer matrix. This contaminant immobilization approach has several attractive features. Urea hydrolysis is catalyzed by the urease enzyme, which is produced by many indigenous subsurface microorganisms. Addition of foreign microbes is unnecessary. In turn the involvement of the native microbes and the consequent in situ generation of reactive components in the aqueous phase (e.g., carbonate and Ca or Sr) can allow dissemination of the reaction over a larger volume and/or farther away from an amendment injection point, as compared to direct addition of the reactants at

  10. A selective molecularly imprinted polymer for immobilization of acetylcholinesterase (AChE): an active enzyme targeted and efficient method.

    PubMed

    Demirci, Gökhan; Doğaç, Yasemin İspirli; Teke, Mustafa

    2015-11-01

    In the present study, we immobilized acetylcholinesterase (AChE) enzyme