Different Methods Of Purification Research Articles

Purification and drying methods of sericin from Bombyx mori cocoons

Different methods of purification and drying of sericin were evaluated to obtain a material free of contaminating residues through the development of safer and sustainable environmental technology. Samples purified using different proportions of alcohol solvents and by freezing/thawing were compared, while drying was performed by lyophilisation and atomisation in a spray. No significant statistical differences were observed in the yield of the purification process compared with the evaluated methods. Thus, the freezing/thawing method has economic and environmental advantages over other methods. Drying by spraying and lyophilisation produced particles exhibiting different properties in terms of structure: β-sheets, random sheets, and β-turns. In general, these particles are amorphous. The particles obtained by spray drying were more luminous, soluble, and spherical. Thus, purification by freezing/thawing and drying by spray can be considered appropriate methodologies for obtaining contaminant-free sericin through sustainable environmental technology.

<b>Bacteriocin-like inhibitory substance in aquaculture: a classic method of protein precipitation for a new aplicability

Techniques to decrease losses from bacterial diseases are always important to improve the fish production. The use of antagonistic substances (bacteriocins) has been proven to be a viable option. The aim of this study was to evaluate different methods of purification for bacteriocin like inhibitory substances (BLIS). For the purification process, we isolated and used two Gram-positive bacilli that produce antagonistic substances for pathogens in aquaculture. Tests for detection of interfering factors were also performed. After the confirmation that the antagonistic action was due the BLIS activity, we carried out the purification methods. The methods tested were: cell free supernatant, acid extraction and ammonium sulfate precipitation at two concentrations (20 and 50%). Salmonella Tiphy CFP/IAL1472 and Aeromonas hydrophila (isolated in a tilapia production environment) were used as indicators of the efficiency of extracts in controlling pathogenic potentials. A mmonium sulfate precipitation at 50% was the most appropriate for purifying the antagonistic substance for both indicators. The extracts of the two isolates remained active for 22 days at 25oC. These are promising results regarding the water and fish health without the use of antibiotics, in this manner being a safer environmental practice.

Comparison and Analysis of Different Methods for Purification of Autoimmune Antibody Reactive with Single Stranded DNA: A Pilot Study

Comparison and Analysis of Different Methods for Purification of Autoimmune Antibody Reactive with Single Stranded DNA: A Pilot Study

Quantitative comparison of structure and dynamics of elastin following three isolation schemes by 13C solid state NMR and MALDI mass spectrometry

Methods for isolating elastin from fat, collagen, and muscle, commonly used in the design of artificial elastin based biomaterials, rely on exposing tissue to harsh pH levels and temperatures that usually denature many proteins. At present, a quantitative measurement of the modifications to elastin following isolation from other extracellular matrix constituents has not been reported. Using magic angle spinning 13C NMR spectroscopy and relaxation methodologies, we have measured the modification in structure and dynamics following three known purification protocols. Our experimental data reveal that the 13C spectra of the hydrated samples appear remarkably similar across the various purification methods. Subtle differences in the half maximum widths were observed in the backbone carbonyl suggesting possible structural heterogeneity across the different methods of purification. Additionally, small differences in the relative signal intensities were observed between purified samples. Lyophilizing the samples results in a reduction of backbone motion and reveals additional differences across the purification methods studied. These differences were most notable in the alanine motifs indicating possible changes in cross-linking or structural rigidity. The measured correlation times of glycine and proline moieties are observed to also vary considerably across the different purification methods, which may be related to peptide bond cleavage. Lastly, the relative concentration of desmosine cross-links in the samples quantified by MALDI mass spectrometry is reported.

English

 Abstract— Our nature and natural resources are the real teachers of our engineers. In wastewater engineering, one of the most sophisticated methods of wastewater treatment is the tertiary treatment or biological treatment. Methods such as biodisc, biofiltration and activated sludge use tiny organisms to remove organic and inorganic pollutants from wastewater. Other higher levels of organisms, such as plants, have been also used for polluted water purification. In phytoremediation, with its different methods of purification, plants are used to remove pollutants from wastewater. Other organisms such as algae, shellfish and fish can be also applied for wastewater treatment. In this paper, the results of the research on using organisms to remove pollutants such as heavy metals from different kinds of wastewaters are presented. The researches were either based on the measurements on nature, or pilot studies in the laboratory. We used water hyacinth to remove nitrate, phosphate, BOD5 and COD from municipal wastewater. The common reed and some other aquatic plants were used for the purification of wastewaters discharged from oil industries and gas purification factories. The concentrations of metals were measured in tissues of organisms exposed to polluted waters in nature; organisms such as algae, fish, shellfish, plants and worms. High concentrations of metals were observed in the organism tissues, suggesting they are favorable for wastewater treatment. The results suggest that a combination of methods would be the most appropriate and in most cases economic method for the treatment of different types of wastewater.

English

The increase in energy demand coupled with the depletion of fossil fuels has increased the need for renewable and sustainable energy sources. Butter waste effluent was identified as a possible feedstock for biodiesel. The effects of the temperature, alcohol to oil molar ratio, catalyst concentration and the reaction time were investigated to determine the optimal reaction conditions of the transesterification reaction. The optimal reaction conditions according to the results were 50°C, 6:1 alcohol to oil molar ratio, 1.0 to 1.2 wt% catalyst loads and a reaction time of 60 to 90 min. Different methods of purification were investigated in an attempt to decrease waste of a biodiesel plant, including the dry washing agents, Magnesol ® D-SOL TM and Purolite ® PD-206. The Magnesol ® D-SOL TM was found to be the optimum method for lowering the water content and the acid value of the fuel. The biodiesel was tested according to the SANS 1935:2011 standard and did not meet the requirements of the standard with regard to flash point, sulphur content, carbon residue, oxidation stability, free glycerol, total glycerol and cold filter plugging point. In order for the biodiesel to be suitable for commercial use, it should be blended with mineral diesel.

Analysis of prospects of pervaporation polymer membranes for biogas treatment

Markets of renewable energy are growing rapidly, and one of the main areas of this development is the application of biogas as an alternative energy source. One of the arguments in favor of biogas is the necessity to resolve the environmental problems, arising from the disposal of wastes at the present level. However, the application of biogas requires its profound purification from carbon oxide (CO), carbon dioxide (CO2), hydrogen (H2), hydrogen sulfide (H2S), which are its invariable components. Nowadays we know and apply different methods of purification, but the most of them require phase changes. The phase transitions lead to the significant energy losses during the division. However, the most promising area of the purification is the application of membrane technologies, in particular the pervaporation. The polymer membranes with different monomers and of different morphology and geometry are especially widely used for the purification of gases. The article concerns the analysis of prospects of the application of polymer membranes made of different polymers, their properties and ways of improvement, which in turn affect the purification of biogas

Isolation of Candida rugosa lipase isoforms

Convenient source of lipases for science and industry is yeast Candida rugosa. Crude preparation of Candida rugosa lipase (CRL) consists of several extracellular lipases. Isoenzyme profile depends on the culture or fermentation conditions. All isoforms are coded by lip pseudogene family; they are monomers of 534 amino acids and molecular weight of about 60 kDa. They share the same catalytic mechanism and interfacial mode of activation. Isoenzymes differ in isoelectric points, post-translational modifications, substrate specificity and hydrophobicity. The presence of different lipase isoforms and other substances (i. e. inhibitors) in crude preparation leads to lack of their productivity in biocatalytic reactions. Purification of specific isoform improves its overall performance and stability. This paper provides an overview of different methods for purification of CRL isoenzymes up to date, their advantages and disadvantages.

Study on Hot Processing Maps and Flow Instability of 1235 Al Alloy Treated by Different Methods of Purification

Based on the theory of processing map proposed by PRASAD, the power dissipation maps, the hot deformation instability maps and the hot processing maps of 1235 Al alloys treated by different methods of purification were built, and the effects of purification and deformation conditions at elevated-temperature on hot workability of 1235 Al alloy were analyzed. At the same time the optimum processing region and flow instability region were determined. The results show that the hot processing map of 1235 Al alloy has two instability zones in the temperature range of 300-500°C and in the strain rate ranging from 0.01s-1to 10.0s-1up to a true strain of 0.7, that is, one zone lying in the range of lower temperature and higher strain rate, the other zone in the range of higher temperature and mid strain rate. The purification effect has significant impact on hot workability of the alloy. It is found that the optimum processing region of 1235 Al alloy treated by high-efficient purification treatment is present in the range of higher temperature and lower strain rate zone, and its power dissipation efficiency is about 46%; while the optimum processing region of 1235 Al alloys treated by conventional refining treatment is present in the range of mid-temperature and lower strain rate zone or in the range of higher temperature and strain rate zone, and its power dissipation efficiency is about 23-29%. The results of observation of the deformation microstructure of 1235 Al alloy are in accordance with that of the hot processing maps of the alloy, thus showing that the calculation results of the hot processing maps are reliable.

Ácido Poliláctico (PLA): Propiedades y Aplicaciones

The polilactic acid (PLA), is a thermoplastic biopolymer which precursor molecule is the lactic acid. Due to its biodegradability, barrier properties and biocompatibility; this biopolymer had found industrial and medicals applications since it presents a wide range of unusual properties, from the amorphous to the crystalline state. These properties could be manipulate with blends between D(-) and L(+) isomers, molecular weight and copolymerization. This article is a review of polilactic acid its polymerizations forms, physicals and mechanicals interesting properties, biodegradability and reabsorption mechanisms and applications in different fields. Besides, it tried about the biotechnological production process of its precursor molecule, emphasizing the research in news substrates, new producers microorganism and different methods of purification.

Evaluation of Taenia saginata metacestodes antigenic fractions for the diagnosis of human neurocysticercosis

The application of Taenia saginata metacestodes as heterologous antigen is an important alternative for neurocysticercosis (NC) serodiagnosis. The cross-reaction with Echinococcus granulosus infection occurs with homologous and heterologous antigens, and could be avoid using different methods of purification. […] Evaluation of Taenia saginata metacestodes antigenic fractions for the diagnosis of human neurocysticercosis (abstract). Thesis. Uberlândia, 2008

Investigation of multicomponent fluoride optical materials in the UV spectral region: I. Single crystals of Ca1−x R xF2+x (R = Sc, Y, La, Yb, Lu) solid solutions

Crystalline materials that are transparent in the vacuum UV spectral region and currently used have been reviewed. Transmission of crystals of solid solutions with the fluorite structure Ca1−xRxF2+x (R = Sc, Y, La, Yb, Lu) in the UV and vacuum UV spectral regions has been investigated. It is shown that application of different methods of purification of fluorides from some impurities can significantly improve the optical quality of fluoride multicomponent crystals in the short-wavelength spectral region.

Purification and characterization of proteasomes from Saccharomyces cerevisiae.

The proteasome plays a central role in eukaryotic cells since it is responsible for the degradation of specific proteins involved in a large range of cellular processes. Analysis of proteasome mechanisms of action, or in vitro reconstitution, or dissection of the complex biological pathways in which it partakes, requires a reliable source of pure active proteasome. Although the biologically relevant form of the proteasome is usually considered to be the 26S proteasome, this unit describes different methods for purification and study of both 26S and 20S proteasomes from Saccharomyces cerevisiae cells.

Reduced‐Scale Large‐Zone Analytical Gel‐Filtration Chromatography for Measurement of Protein Association Equilibria

The proteasome plays a central role in eukaryotic cells since it is responsible for the degradation of specific proteins involved in a large range of cellular processes. Analysis of proteasome mechanisms of action, or in vitro reconstitution, or dissection of the complex biological pathways in which it partakes, requires a reliable source of pure active proteasome. Although the biologically relevant form of the proteasome is usually considered to be the 26S proteasome, this unit describes different methods for purification and study of both 26S and 20S proteasomes from Saccharomyces cerevisiae cells.

Reversible Phosphorylation of the C-terminal Domain of RNA Polymerase II

Reversible Phosphorylation of the C-terminal Domain of RNA Polymerase II

Preparation and characterization of conjugates of recombinant CD4 and deglycosylated ricin A chain using different cross-linkers

In a previous study, we have demonstrated that conjugates containing soluble, recombinant human CD4 (rCD4) and the deglycosylated form of ricin A chain (dgA) (rCD4-dgA) effectively kill a human T cell line infected with the human immunodeficiency virus (HIV) in vitro. In contrast, such conjugates are 100-1000-fold less toxic to uninfected cells. In order to use a rCD4-dgA conjugate effectively in vivo, it was important to demonstrate that (1) it binds to and kills HIV-infected, but not uninfected, human cells, (2) it is stable in the circulation, and (3) it has an optimal therapeutic index (toxicity to animals versus toxicity to target cells). A major factor affecting the efficacy of such conjugates in vitro and in vivo is the nature of the cross-linker between the ligand (rCD4) and the toxin (dgA). In this report, we have prepared rCD4-dgA conjugates using three different cross-linkers. Different methods of purification have been compared by determining the optimal yield, purity, and retention of biological activity (i.e., binding to gp120 and dgA chain activity). The structure of these conjugates as well as their cytotoxicity to target cells in vitro has been analyzed. Finally, we have compared their pharmacokinetics, tissue localization, and toxicity in mice.

Photoconductivity of degassed ethers as a function of their purity

The pulse d.c. photoconductivity (PC) of the vacuum-degassed ethers tetrahydrofuran (THF), ethyl ether (Et 2O) and 1,4-dioxane was investigated. It was found that after a light pulse of duration 1 ms in degassed THF or Et 2O the photocurrent rises. A monophotonic ionic photodissociation is responsible for the charge generation since the photosignals were proportional to the amount of absorbed light. The photocurrent signals decreased exponentially with first-order rate constants which decreased linearly with the decreasing voltage applied between the platinum electrodes. This might indicate that the fairly stable photoproduced ions disappear mainly in the electrode discharge reactions. The bulk recombination, which is probably preceded by a monomolecular or pseudomonomolecular rearrangement (since this is a process also well described by an exponential equation) did not exceed about 10% of the total ion consumption under the conditions used. After examining different methods of purification of the ethers studied it was found that the phenomenon was caused by electron acceptor impurities, which were mainly the products of the oxidation of ethers. In the case of 1,4-dioxane the PC signals were hardly detectable, since the lower polarity of this solvent did not favour ionic dissociation of the ion pairs which are probably also produced. An improved method of purification of these ethers is proposed.

Effects of different methods of purification on aggregation of scrapie infectivity.

High levels of scrapie infectivity were found in detergent-insoluble residues of hamster brain purified by either repeated pelleting in 10% NaCl or by separation in Nycodenz gradients. Titres determined by the method of incubation interval assay were 100-fold higher than titres measured by endpoint dilution assay. The protein profiles and end-labelled RNA examined by one-dimensional polyacrylamide gel electrophoresis were not different from samples prepared from uninfected brain. Preparations produced by repeated pelleting were treated with RNase A and/or 7 M-urea with no loss of scrapie infectivity. However, the infectivity of samples prepared by gradient centrifugation in Nycodenz were reduced by 2 to 3 log10 LD50 by treatment with RNase A alone but not in combination with SDS. These results suggest that the scrapie agent may be aggregated by methods of purification employing pelleting in high concentrations of salt, or by adding polycations to disaggregated samples.

Purification of spin-labelled DNA by hydroxyapatite chromatography

Electron paramagnetic resonance (EPR) spectroscopy is widely used for studying the structure and conformation of RNA and proteins, but it is a relatively new method for investigation of DNA. On the basis of the few articles availablel-s, it can be concluded that the EPR spectra of spin-labelled DNA are only weakly immobilized1s4. This limits the application of the method when studying the fine structural and conformational changes in DNA molecules. Our experience in spin-labelling of DNA with alkylating spin-labels shows that in many cases the “weakly immobilized”1*4 EPR spectrum may be due to the presence of unbound spin probe in the measured DNA preparation. It should be also that conventional method for separation of DNA and low-molecular-weight substances do not give satisfactory results when applied to the purification of spin-labelled DNA from the unbound spin-label. In the present study we compare the efficiency of different methods for purification of spin-labelled DNA from low-molecular-weight spin-labelled compounds.

The biological and physico-chemical characteristics of meningococcus polysaccharide group C prepared by two different methods of purification

We wished to evaluate the physico-chemical and biological characteristics of meningococcus polysaccharide group C prepared by two different methods of purification: cold phenol alone and cold phenol with the addition of two extractions with a chloroform- n -butanol mixture. With the latter method we obtained a polysaccharide less pyrogenic than that obtained with the procedure using only cold phenol. The physico-chemical characteristics of the polysaccharides obtained by the different procedures were identical.