Microfluidic Multiple Chamber Chip Reactor Filled with Enzyme-Coated Magnetic Nanoparticles

In this chapter, a novel microfluidic device (MagneChip) is described which comprises microliter volume reaction chambers filled with magnetically fixed enzyme-coated magnetic nanoparticles (ecMNPs) and with an in-line UV detector. In the experiments, MNPs with phenylalanine ammonia-lyase (PAL)—an enzyme which catalyzes the deamination of l-phenylalanine (Phe) to (E)-cinnamate in many organisms—immobilized on the surface were applied as biocatalyst to study the characteristics of the MagneChip device. In the reaction chambers of this microfluidic device, the accurate in situ quantization of the entrapped MNPs was possible using a resonant coil magnetometer integrated below the chambers. Computational fluid dynamics (CFD) calculations were used to simulate the flow field in the chambers. The enzyme-catalyzed biotransformations could be performed in the chip with excellent reproducibility and of repeatability. The platform enabled fully automatic multiparameter measurements with a single biocatalyst loading of about 1 mg PAL-ecMNP in the chip. A study on the effect of particle size and arrangement on the catalytic activity revealed that the mass of ecMNPs fixed in the chamber is independent of the particle diameter. Decreasing the particle size resulted in increasing catalytic activity due to the increased area to volume ratio. A binary mixture of particles with two different particle sizes could increase the entrapped particle mass and further the catalytic activity compared to the best uniform packing. The platform enabled a study of biotransformation of l-phenylalanine and five unnatural substrates by consecutive reactions using same PAL-ecMNP loading. With the aid of the platform, we first demonstrated that PAL can catalyze the ammonia elimination from the noncyclic propargylglycine as substrate

Radioactive wastewater treatment using selective ion exchangers

It is well known that in the Hungarian PWR-type nuclear power plant Paks the radioactive waste waters are collected in common tanks. These water streams contain radioactive isotopes in ultra-low concentration and inactive compounds as major components (borate 1.7 g/dm3, sodium-nitrate 0.4 g/dm3, sodium-hydroxide 0.16 g/dmsupyy3/sup, and oxalate 0.25 g/dm3). These low salinity solutions were evaporated by adding sodium-hydroxide, until 400 g/dmsupyy3/sup salt content is reached. There is about 6000 m3 concentrated evaporator bottom residues in the tanks of the PWR. We have developed a complex technology for the selective separation of the long live radionuclides and for the partial recycle of boric acid from this evaporator bottom residue. A wastewater treatment system has been developed by using a cesium selective inorganic ion exchanger. The selective separation of cesium (137Cs, 134Cs) from high salt concentration and strongly alkaline evaporator bottom residue in Paks Nuclear Power Plant has a volume reduction factor about 1800-3500 at the value of the decontamination factor DF > 100, for the samples of four tanks of the Hungarian PWR Paks

NEW TECHNOLOGY SCHEME FOR HANDLING AND BURIAL FOR THE RADIOACTIVE EVAPORATOR BOTTOM OF THE PWR PAKS

At the Department of Chemical Technology we developed a complex technology for handling the radioactive evaporator bottom in Paks before burial. The basic concept of the technology is the primary selective separation of the long-lived radioisotopes and then the partial recovery of the boric acid content of the inactive solution. The selective separation is accomplished by using iom exchange and adsorption materials and reagents and the partial recovery of the boric acid content of the inactive solution. The selective separation is accomplished by using ion exchange and adsorption materials and reagents and the partial recovery of the boric acid is carried out by neutralisation with carbon dioxide combined with a purification step involving ammonium-ion exchange. The overall volume reduction factor is about 96

Electrospun Nanofibers for Entrapment of Biomolecules

This chapter focuses on nanofiber fabrication by electrospinning techniques for the effective immobilization of biomolecules (such as enzymes or active pharmaceutical ingredients—APIs). In this chapter, the development of precursor materials (from commercial polymer systems to systematically designed biopolymers), entrapment protocols, and precursor-nanofiber characterization methods are represented. The entrapment ability of poly(vinyl alcohol) and systematically modified polyaspartamide nanofibers was investigated for immobilization of two different lipases (from Candida antarctica and Pseudomonas fluorescens) and for formulation of the antibacterial and antiviral agent, rifampicin. The encapsulated biomolecules in electrospun polymer fibers could be promising nanomaterials for industrial biocatalysis to produce chiral compound or in the development of smart drug delivery systems

Electrospun polylactic acid and polyvinyl alcohol fibers as efficient and stable nanomaterials for immobilization of lipases

Electrospinning was applied to create easy-to-handle and high- surface-area membranes from continuous nanofibers of polyvinyl alcohol (PVA) or polylactic acid (PLA). Lipase PS from Burkholderia cepacia and Lipase B from Candida antarctica (CaLB) could be immobilized effectively by adsorption onto the fibrous material as well as by entrapment within the electrospun nanofibers. The biocatalytic performance of the resulting membrane biocatalysts was evaluated in the kinetic resolution of racemic 1-phenylethanol (rac-1) and 1-phenylethyl acetate (rac- 2). Fine dispersion of the enzymes in the polymer matrix and large surface area of the nanofibers resulted in an enormous increase in the activity of the membrane biocatalyst compared to the non-immobilized crude powder forms of the lipases. PLA as fiber-forming polymer for lipase immobilization performed better than PVA in all aspects. Recycling studies with the various forms of electrospun membrane biocatalysts in ten cycles of the acylation and hydrolysis reactions indicated excellent stability of this forms of immobilized lipases. PLA-entrapped lipases could preserve lipase activity and enantiomer selectivity much better than the PVA-entrapped forms. The electrospun membrane forms of CaLB showed high mechanical stability in the repeated acylations and hydrolyses than commercial forms of CaLB immobilized on polyacrylamide beads (Novozyme 435 and IMMCALB- T2-150). © 2016 Springer-Verlag Berlin Heidelber

Conservation of the Biocatalytic Activity of Whole Yeast Cells by Supported Sol – Gel Entrapment for Efficient Acyloin Condensation

In this study, an efficient and generally applicable 2nd generation sol – gel entrapment method was developed for immobilization of yeastcells. Cells of Lodderomyces elongisporus, Candida norvegica, Debaryomyces fabryi, Pichia carsonii strains in admixture with hollow silica microspheres support were immobilized in sol – gel matrix obtained from polycondensation of tetraethoxysilane. As biocatalysts in theselective acyloin condensation of benzaldehyde catalyzed by pyruvate decarboxylase of the yeast, the novel immobilized whole-cell preparations were compared to other states of the cells such as freshly harvested wet cell paste, lyophilized cells and sol – gel entrapped preparations without hollow silica microspheres support. Reusability and storability studies designated this novel 2nd generation sol – gel method as a promising alternative for solid formulation of whole-cells bypassing expensive and difficult downstream steps while providing easy-to-handle and stable biocatalysts with long-term preservation of the biocatalytic activity

Cellulóz alapú szálasanyagok módosítása alkalmazási lehetőségeik bővítése céljából = Modification of cellulosic fibers for extension of their application

A cellulóz a természetben megújuló értékes nyersanyag, sokféle új hasznos termék kiindulásául szolgálhat. PAMUTCELLULÓZ DUZZASZTÁSA: A duzzasztás után oldószercserével szárított minták BET felülete 6 mol dm-3 NaOH, ill. 3 mol dm-3 tetrametil-ammónium-hidroxid alkalmazásakor közel azonos, a kiindulási cellulózénak kb. 12-szerese. A kvaterner ammónium hidroxidok intrakrisztallitos duzzasztásra alkalmas koncentrációja - a vártnak megfelelően - a molekulatömeg növekedésével csökken. PAMUTCELLULÓZ KÉMIAI MÓDOSÍTÁSA a) Alkilezés (karboxi-metilezés, DS < 0,1): A karboxi-metilezési eljárást az alkalmazott vegyszerkoncentráció és reakcióhőmérséklet csökkentésével továbbfejlesztettük. A kismértékű karboxi-metilezés csökkenti a cellulóz termikus stabilitását; kalcium- és cinksók jelenléte további stabilitáscsökkenést okoz. A módosított pamutszövet - savas jellegénél fogva - 3-5 nagyságrenddel csökkenti a mikroorganizmusok számát. b) Ojtás: Nagyenergiájú sugárzást előzetesen, ill. a monomer jelenlétében alkalmazva különböző monomerekkel többféle cellulóz kopolimert állítottunk elő A megnőtt hidrofilitás és adszorpciós kapacitás pl. szennyvíztisztításra, csökkent hidrofilitás és polaritás szálerősítésű kompozitoknál a kompatibilitás növelésében lehet előnyös. ROSTKENDER KÍMÉLETES FINOMÍTÁSA: Ultrahang alkalmazásával a kenderrost átlagos átmérője csökkent, a lené nem változott, a len porozitása csökkent, a kenderé nőtt. | Cellulose as a renewable raw material can be used to obtain new products. SWELLING OF COTTON CELLULOSE: Samples swollen in 6 mol dm-3 NaOH, and 3 mol dm-3 tetramethylammonium hydroxide, respectively, were dried after solvent exchange in vacuum. Their BET surfaces were nearly the same; this value is twelve times larger than that of the original cellulose. As expected, quaternary ammonium hydroxides' concentrations for intracrystalline swelling of cellulose are decreasing as function of molecular mass. CHEMICAL MODIFICATION OF COTTON CELLULOSE: a) Alkylation (carboxymethylation, DS<0,1): A new carboxymethylation technology was developed by decreasing reagent concentrations and temperature. Slight carboxymethylation decreases the thermal stability of cellulose; calcium and zinc salts cause a further decrease. The modified cellulose decreases the number of microbes by 3-5 orders of magnitude due to its acidic character. b) Grafting: Cellulose copolimer samples were manufactured by direct and by preirradiation grafting methods using various monomers. Samples of improved hydrophylicity and sorption capacity can be used e. g. for waste water cleaning, while less hydrophyl and less polar products can be useful in fibre reinforced polymer composites due to better compatibility. MILD REFINEMENT OF INDUSTRIAL HEMP - SONICATION: Average fibre diameter of hemp decreased, that of flax didn't change; porosity of flax decreased, while that of hemp increased

Novel biomimetic nanocomposite for investigation of drug metabolism

In vitro mimicking of hepatic drug metabolism is a key issue in early-stage drug discovery. Synthetic metalloporphyrins show structural similarity with the heme type prosthetic group of cytochrome P450 as primary hepatic enzyme in oxidative drug biotransformation. Therefore, they can catalyze these oxidations. Concerning economical aspects and the poor stability of metalloporphyrin, their immobilization onto or into solid carriers can be promising solution. This study presents a novel immobilized metalloporphyrin nanocomposite system and its potential use as biomimetic catalysts. The developed two-step immobilization procedure consists of two main steps. First, the ionic binding of meso-tetra (parasulphonatophenyl) iron porphyrin onto functionalized magnetic nanoparticles is established, followed by embedding the nanoparticles into polylactic acid nanofibers by electrospinning technique. Due to the synergistic morphological and chemo-structural advantages of binding onto nanoparticles and embedding in polymeric matrices the biomimetic efficiency of metalloporphyrin can be remarkably enhanced, while substrate conversion value was tenfold larger than which could be achieved with classic human liver microsomal system