Hiraoka Y.,Yuki Gosei Kogyo Co. |
Taniike T.,Japan Advanced Institute of Science and Technology |
Kusano M.,Yuki Gosei Kogyo Co. |
Ikoma Y.,Yuki Gosei Kogyo Co. |
Terano M.,Japan Advanced Institute of Science and Technology
Kobunshi Ronbunshu | Year: 2011
In this study, we clarified the effects of the preparation methods of TiC 4/Internal donor/MgCI 2 propylene polymerization catalysts on the structure of the active site and particle morphology, active sites nature and their dispersion in the particle. The morphology of the original catalyst and their produced polypropylene particles were studied by direct scanning electron microscopy and particle size distribution analysis. Stopped-flow polymerization technique in combination with crystallinity distribution analysis of the obtained polymers was used for kinetic analysis. It was shown that the polymer particle morphology and their fragmentation/growth were controlled by the spatial distribution of active Ti species in the catalyst particle, which was different among catalyst preparation methods. Even the polymer morphology directly depends on the type ofcatalyst particle. Even though the catalyst preparation method hardly affects the molecular structures of active sites, the ratio of two isospecific catalytic sites in the catalyst was dependent on the preparation method. © 2011 The Society Of Ploymer Science, Japan.
Hiraoka Y.,Japan Advanced Institute of Science and Technology |
Hiraoka Y.,Yuki Gosei Kogyo Co. |
Kim S.Y.,Japan Advanced Institute of Science and Technology |
Dashti A.,Japan Advanced Institute of Science and Technology |
And 2 more authors.
Macromolecular Reaction Engineering | Year: 2010
Though preparation procedures of heterogeneous Ziegler-Natta catalysts for propylene polymerization are sophisticated, it is uncertain whether the nature of the active sites is similar or different for different preparation procedures. In this study, the effects of preparation procedures on the nature of the active sites were investigated by stopped-flow polymerization in combination with microstructure analysis of polymers. Both basic and advanced types of catalysts showed the same two kinds of isospecific active site, which indicated little influence of the preparation method on the active site structure. On the contrary, the ratios of the two kinds of isospecific sites were not the same, resulting in variation of average polymer properties. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PubMed | Chulalongkorn University, Yuki Gosei Kogyo Co., Japan Advanced Institute of Science and Technology and Samsung
Type: Journal Article | Journal: Science and technology of advanced materials | Year: 2016
Horinouchi N.,Kyoto University |
Sakai T.,Kyoto University |
Kawano T.,Kyoto University |
Matsumoto S.,Yuki Gosei Kogyo Co. |
And 5 more authors.
Microbial Cell Factories | Year: 2012
Background: Reproduction and sustainability are important for future society, and bioprocesses are one technology that can be used to realize these concepts. However, there is still limited variation in bioprocesses and there are several challenges, especially in the operation of energy-requiring bioprocesses. As an example of a microbial platform for an energy-requiring bioprocess, we established a process that efficiently and enzymatically synthesizes 2′-deoxyribonucleoside from glucose, acetaldehyde, and a nucleobase. This method consists of the coupling reactions of the reversible nucleoside degradation pathway and energy generation through the yeast glycolytic pathway.Results: Using E. coli that co-express deoxyriboaldolase and phosphopentomutase, a high amount of 2′-deoxyribonucleoside was produced with efficient energy transfer under phosphate-limiting reaction conditions. Keeping the nucleobase concentration low and the mixture at a low reaction temperature increased the yield of 2′-deoxyribonucleoside relative to the amount of added nucleobase, indicating that energy was efficiently generated from glucose via the yeast glycolytic pathway under these reaction conditions. Using a one-pot reaction in which small amounts of adenine, adenosine, and acetone-dried yeast were fed into the reaction, 75 mM of 2′-deoxyinosine, the deaminated product of 2′-deoxyadenosine, was produced from glucose (600 mM), acetaldehyde (250 mM), adenine (70 mM), and adenosine (20 mM) with a high yield relative to the total base moiety input (83%). Moreover, a variety of natural dNSs were further synthesized by introducing a base-exchange reaction into the process.Conclusion: A critical common issue in energy-requiring bioprocess is fine control of phosphate concentration. We tried to resolve this problem, and provide the convenient recipe for establishment of energy-requiring bioprocesses. It is anticipated that the commercial demand for dNSs, which are primary metabolites that accumulate at very low levels in the metabolic pool, will grow. The development of an efficient production method for these compounds will have a great impact in both fields of applied microbiology and industry and will also serve as a good example of a microbial platform for energy-requiring bioprocesses. © 2012 Horinouchi et al.; licensee BioMed Central Ltd.