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Recovery of active medium-chain-length-poly-3-hydroxyalkanoate polymerase from inactive inclusion bodies using ion-exchange resin.

A novel process for the purification of active medium-chain-length-polyhydroxyalkanoate (mcl-PHA) polymerase was developed. This process is based on solubilization and activation of inactive polymerase inclusion bodies by incubation with ion-exchange resin. The mcl-PHA polymerase 1 from Pseudomonas oleovorans was overproduced from the Palk promoter. Most of the polymerase produced was sequestered in the cytoplasm as an inactive form in insoluble aggregates. By incubating the protein aggregates with S-Sepharose ion-exchange resin in the presence of dithiothreitol and glycerol, the mcl-PHA polymerase could be extracted in an active and soluble form with a final yield of about 5.2 mg/g of cell dry weight. The solubilized polymerase was able to catalyse the in vitro synthesis of mcl-PHA without any additional cell components, suggesting its potential application for production of biopolymer. The procedure used here may be of general value in solubilizing and activating purified inactive labile enzymes.

Acyltransferases↗

Adsorption characteristics of Cu(II) onto ion exchange resins 252H and 1500H: kinetics, isotherms and error analysis.

The adsorption of Copper(II) onto Amberjet 1500H and Ambersep 252H synthetic ion exchange resins have been studied. All the studies were conducted by a batch method to determine equilibrium and kinetic studies at the solution pH of 5.8 in the concentration ranges from 10 to 20mg/L. The experimental isotherm data were analyzed using the Freundlich, Langmuir, Redlich Perterson, Temkin, Dubinin-Radushkevich equations. Correlation co-efficient was determined for each isotherm analysis. Error functions have been used to determine the alternative single component parameters by non-linear regression due to the bias in using the correlation coefficient resulting from linearisation. From the error analysis the EABS error function provides the best parameters for the isotherm equation in this system. Adsorption kinetics data were tested using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second-order reaction. The initial sorption rate, pseudo-first-order, pseudo-second-order and intraparticle diffusion rate constants for different initial concentrations were evaluated and discussed.

Adsorption↗

Pseudohypoaldosteronism in a child with Down syndrome. Long-term management of salt loss by ion exchange resin administration.

At 4 weeks of age, an infant with Down syndrome developed severe dehydration and salt loss with the typical features of pseudohypoaldosteronism (PHA). Plasma renin activity, 11-deoxycorticosterone, corticosterone and aldosterone levels were all increased several-fold over the normal range for age, thus excluding an adrenal biosynthetic defect. Clinical condition, hyponatraemia and hyperkalaemia could be rapidly normalised by the ion exchange resin Resonium A administered first as enema and later orally (3 g/day). At that time, no further salt supplementation was necessary. At 18 months of age, Resonium A could be completely withdrawn with neither clinical deterioration nor electrolyte abnormalities. However at 3 1/2 years of age, plasma renin activity and aldosterone were still markedly elevated while precursor steroids were normal and the clinical condition satisfactory. No side effects were observed with the Resonium A therapy. The combination of trisomy 21 and PHA is very unusual. Similarly, the successful treatment of severe renal salt loss during infancy by sodium supplementation and concomitant potassium withdrawal via an oral ion exchange resin has not yet been described and warrants further therapeutic trials.

Aldosterone↗

Impact of a magnetic ion exchange resin on ozone demand and bromate formation during drinking water treatment.

The objective of this research was to examine the impact of a magnetic ion exchange resin (MIEX) on ozone demand and bromate formation in two different ozonated waters at bench scale. The first raw water had a high bromide ion concentration, a high ozone demand, and was highly colored. Based on experimental findings from the first water, the second water was selected as a model water in which more controlled experiments were performed. The waters were treated with the MIEX resin using jar test procedures to find the optimal MIEX dosage based upon the removal of ultraviolet (UV)-absorbing substances, dissolved organic carbon (DOC), and bromide. The optimal resin dosage was chosen for bulk MIEX treatment and subsequent ozonation in a semi-batch reactor. The ozone demand and formation of bromate were analyzed as a function of ozone dosage and dissolved ozone concentration for the MIEX pre-treated water, and compared to the results obtained by ozonating the water without MIEX pre-treatment. The results indicate that pre-treatment of the water with the MIEX resin significantly reduces total organic carbon, DOC, UV absorbance, color, and to some extent, bromide. MIEX pre-treatment of the water prior to ozonation substantially lowered the ozone demand and formation of bromate during subsequent ozonation.

Bromates↗