Immobilization of lactase to Perloza cellulose resins : a thesis was presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University

A bead cellulose matrix, Perloza, was chemically modified by two attachment chemistries to prepare inexpensive resins for immobilization of lactase. A commercial product, the base-activated matrix Eupergit C was studied for comparison. Three types of Perloza (Perloza 100 MT, Perloza 200 MT, Perloza 500 TM) were activated by epichlorohydrin (ECH) to achieve different activation levels. The best result for lactase immobilization was gained at low activation level (activated at 2% NaOH) for two attachment chemistries. The first attachment chemistry studied was that lactase immobilized directly to ECH activated Perloza. The second chemistry again used ECH activation and followed by attachment of the 6-amino caproic acid (ACA) spacer arm and then the lactase. In the first chemistry, Perloza 100-ECH-Lactase obtained the highest activity 11.4 NLU/g (wet resin) over Perloza 200-ECH-Lactase and Perloza 500-ECH-Lactase (40 hours immobilization). In the second chemistry, Perloza 200-ECH-ACA-Lactase retained the highest activity 30.9 NLU/L (wet resin) over Perloza 100-ECH-ACA-Lactase and Perloza 500-ECH-ACA-Lactase. Overall the best results were obtained for the ECH-ACA resins. This best of these results showed about 3 times better immobilization than without ACA spacer arm. The activity of immobilized lactase on Eupergit C obtained was 124~131.3 NLU/g (wet resin) for 24 hours immobilization. Although this result is about four times greater than Perloza, Perloza is a much cheaper matrix. In the storage stability studies, both Perloza and Eupergit C immobilized lactase showed a sharp drop in activity initially within 1 day, then activity loss leveled out. Perloza 200-ECH-ACA-Lactase retained 82% of its original activity after 9 days storage. However, Eupergit-Lactase only retained 39% of its original activity after the same storage period. This result indicated that Perloza 200-ECH-ACA-Lactase may possess much better storage stability than that of Eupergit-Lactase. Studies on the inter-relationships between pH. temperature and Perloza immobilized lactase using the substrate (ONPG) indicated that maximum hydrolysis was attained at pH 6.5-7.2 and over a temperature range of 30-42°C. No shift in the pH and temperature optima in comparison to free enzyme was observed as a result of the process of immobilization of lactase on Perloza for both attachment chemistries. The pH-activity curve of Eupergit-Lactase shifted towards more acidic pH values in the pH optimum in comparison to free lactase. The temperature optimum of Eupergit-Lactase shifted towards higher temperature compared to free lactase. This study showed that Perloza has potential for the large scale use as a matrix of lactase immobilization

Fabrication of Switches on Polymer-Based by Hot Embossing

In MEMS technology, most of the devices are fabricated on glass or silicon substrate. However, this research presents a novel manufacture method that is derived from conventional hot embossing technology to fabricate the electrostatic switches on polymer material. The procedures of fabrication involve the metal deposition, photolithography, electroplating, hot embossing and hot embed techniques. The fundamental concept of the hot embed technology is that the temperature should be increased above Tg of polymer, and the polymer becomes plastic and viscous and could be molded. According to the fundamental concept, the metal layer on the silicon/glass substrate could be embedded into polymer material during the hot embossing process. Afterward, the metal layer is bonded together with the polymer after removing the substrate in the de-embossing step. Finally, the electrostatic switch is fabricated on polymethylmethacrylate(PMMA) material to demonstrate the novel method.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Coulomb energy of axially deformed nucleus

We previously proposed a formula for calculating the Coulomb energy of spherical nucleus with Wood-Saxon charge distribution. In this work, the analytical formula is extended for description of the Coulomb energy of nucleus with beta2 deformation.Comment: 2 figure

Shifts in Redox Formal Potentials Accompanying the Incorporation of Cationic Complexes in Perfluoro Polycarboxylate and Polysulfonate Coatings on Graphite Electrodes

The formal potentials of several redox couples incorporated in coatings of a perfluoropolycarboxylate on graphite electrodes were measured and compared with the formal potentials of the same couples in homogeneous solution. The differences observed agreed with those calculated from the Nernst equation with the independently measured incorporationcoefficients for both halves of the redox couples. The dependences of the shifts in formal potentials on the nature of theincorporating complex ion, the ionic strength, and the temperature were determined and indicated that the incorporationequilibrium is governed by electrostatic and hydrophobic interactions that act in opposite directions. The incorporation ofmost cations examined was driven by large increases in entropy which overcame the usually unfavorable enthalpy changes

The Design and Fabrication of Platform Device for Dna Amplification

Thermalcycler were extensively used machine for amplify DNA sample. One of the major problems in the working time was that it spent most of time for cooling and heating. In order to improve the efficient, this study presented a novel method for amplify DNA sample. For this concept, the DNA sample in the silicon chamber which was pushed by a beam through three temperature regions around a center and then the DNA segments could be amplified rapidly after 30 cycles. The polymerase chain reaction platform was composed of thin-film heaters, copper plates, DC powers, and temperature controllers. The photolithography and bulk etching technologies were utilized to construct the thin-film heater and DNA reaction chambers. Finally, 1 pound gL 100bp DNA segment of E. coli K12 was amplified successfully within 36 minutes on this PCR platform.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions