In recent years the quest for longevity and an improved quality of life has ventured into the realm of natural therapeutics, resulting in a wider acceptance of plant-based medicine in the Western world. This increased...
Rhodococcus erythropolis LSSE8-1 is a newly isolated biodesulfurizaion strain from the soil of Chishui gas field, Guizhou Province, China. The analysis of its metabo-lism product shows that the strain is a kind of bio...
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Rhodococcus erythropolis LSSE8-1 is a newly isolated biodesulfurizaion strain from the soil of Chishui gas field, Guizhou Province, China. The analysis of its metabo-lism product shows that the strain is a kind of biocatalyst able to oxidize dibenzothiophene (DBT) to 2-hydroxydi- phenyl (HBP), and therefore the sulfur in DBT is selectively removed. By using DBTO2 (dibenzothiophene 5,5-dioxide) as substrate, both DBT and HBP are found in the culture, which shows that the reaction from DBT to DBTO2 is re-versible in the cell. While using 0.5 mmol/L DBT as control, 0.01—0.4 mmol/L DBTO2 shows poisonous effect to the cell, which will explain why there is no DBTO2 accumulation in the process of biodesulfurization. After treatment by lysozme, the plasmid DNA of the strain is isolated by alkaline method to be used as the template of PCR reaction. Three dsz gene fragments of 1.3, 1.0 and 1.2 kb respectively were amplified. Each fragment is ligate with PGEM-T vector, and cloned into E. coli. DH5. The clone DNA is sequenced and the result shows that dsz related genes are highly conservative. The identities of dszA and dszB with respect to IGTS8 are 100%, and the identity of dszC with that of IGTS8 is 99%.
Much attention has in recent years been paid to fine applications of polymer particles, e.g., carrier for enzyme, separation media for protein, DNA and cell, and carrier for drug in Drug Delivery System (DDS). Control...
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Much attention has in recent years been paid to fine applications of polymer particles, e.g., carrier for enzyme, separation media for protein, DNA and cell, and carrier for drug in Drug Delivery System (DDS). Control of polymer particle size is especially important in such fine applications. For instance, when the particles are used as a carrier of anti-cancer agents, the locations of particles containing anti-cancer agents also depend on the size of the particles. In this paper, various techniques of controlling polymer particle size are described, with emphasis on Shirasu Porous Glass (SPG) membrane emulsification, as carried out in our research group.
Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA) spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4 nanoparticles ...
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Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA) spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4 nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide (BPO) to form oil in water suspension with the presence of poly(viny) pyrrolidone) (PVP-K30) as a stabilizer. Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets. Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and properties of magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magnetic microspheres obtained have very small size (about 4-7μm) in diameter with narrow size distribution and super-paramagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure for the magnetite dispersed in polymer microspheres. FT-IR spectroscopy indicates extensive oxirane groups existed on the surface of magnetic PSt-DVB-GMA microspheres.
A nondestructive desulfurization microorganism has been isolated. The metabolism product analyses show that the strain can be a kind of biocatalyst to oxidize dibenzothiophene (DBT) into 2-hydroxydiphenyl (HBP), there...
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A nondestructive desulfurization microorganism has been isolated. The metabolism product analyses show that the strain can be a kind of biocatalyst to oxidize dibenzothiophene (DBT) into 2-hydroxydiphenyl (HBP), therefore the sulfur in DBT is removed selectively. The 16SrRNA information, cell wall analysis, physical, biochemical properties and morphological properties suggest that the isolated strain is Rhodococcus erythropolis. The strain can grow in the basal salts medium (BSM) that DBT concentration is no more than 10 mmol/L, and the optimal DBT concentration for growth is 1 mmol/L, however, the optimal DBT concentration for desulfurization is 0.5 mmol/L. The further research shows that the strain can also desulfur some other organosulfur-containing compounds such as thianaphthene, phenyl sulfide and 4,6-dimethyldiben- zothiophene (4,6-DMDBT).
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