http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Naiqiang Yan (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Cadaverine Production by Heterologous Expression of Klebsiella oxytoca Lysine Decarboxylase
Naiqiang Li,Howard Chou,Lijun Yu,Yan Xu 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.6
Cadaverine, as a biogenic amine, is an importantplatform chemical for the production of industrial polymers,such as polyamides, polyurethanes, and nylon. Previousefforts focused on the bio-based production of cadaverineusing two lysine decarboxylases of Escherichia coli CadAand LdcC. In this study, we report the biotransformation ofcadaverine using a lysine decarboxylase from Klebsiellaoxytoca. Codon optimization of the gene encoding thisenzyme was carried on for the heterologous expression inE. coli, which led to a system that converted more than24% lysine-HCl to cadaverine compared to the same systemexpressing CadA. The system was further optimized byusing three different inducible promoters to control theexpression of lysine decarboxylase gene of K. oxytoca inE. coli. The final optimized system converted lysine-HClto cadaverine at a conversion rate of 0.133%/min/g. Whenthe optimized system described above is coupled to anindustrial process, the combined process has the potentialto produce cadaverine with high conversion efficiency(46%) from sugar.
-
Design of Co3O4/CeO2–Co3O4 hierarchical binary oxides for the catalytic oxidation of dibromomethane
Jian Mei,Jiangkun Xie,Yaning Sun,Zan Qu,Naiqiang Yan 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.73 No.-
Developing the catalysts that can efficiently degrade brominated volatile organic compounds (Br-VOCs)is a priority due to the low activity, the low product selectivity, and the low resistance to Br-poisoning. Inthis work, Co3O4/CeO2–Co3O4 hierarchical binary oxides were designed as a high-performance catalystfor the catalytic oxidation of dibromomethane (CH2Br2) as a model pollutant for Br-VOCs. The surface ofcarbon spheres was coated with a layer of CeO2 nanoparticles, and core-shell CSs@CeO2 were theprecursors of Co3O4/CeO2–Co3O4 hierarchical binary oxides. Co3O4/CeO2–Co3O4(HS) had a hierarchicalporous structure, there was a strong interaction between Co3O4 and CeO2 Co3O4/CeO2–Co3O4(HS)showed an excellent catalytic activity, and its T90 value was only 321 C. Meanwhile, Co3O4/CeO2–Co3O4(HS) showed good stability for at least 30 h. Co3O4 provided the active sites for CH2Br2 oxidation,and the hierarchical porous structure and high specific surface area were conducive to the adsorption ofCH2Br2 molecules. Meanwhile, CeO2 promoted the oxygen mobility of the composite and the oxidationperformance of Co3O4. CH2Br2 molecularfirstly adsorbed on Co3O4/CeO2–Co3O4(HS) surface, anddissociated to form the intermediates (i.e., formate species, and methoxy species), which werefinallyoxidized to CO and CO2, and Br species were removed in the form of HBr and Br2.
-
Jian Mei,Zan Qu,Songjian Zhao,Xiaofang Hu,Haomiao Xu,Naiqiang Yan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-
Co3O4 catalysts modified with Mn and Ti, prepared by co-precipitation method, were used for catalytic oxidation of dibromomethane (CH2Br2), a model molecule for brominated volatile organic compounds (BVOCs). Addition of Ti or Ti + Mn distorted the crystal structure and led to the formation of a Co–O–Ti solid solution. The addition of Mn further enhanced the surface acidity and redox ability of the catalysts. Co–Mn–Ti exhibited the highest activity with a T90 of approximately 234 °C and the highest selectivity to CO2 at low temperatures. Additionally, Co–Mn–Ti showed good stability for at least 30 h at 500 ppm CH2Br2, 0 or 2 vol% H2O, 0 or 500 ppm p-xylene (PX), and 10% O2 at a gas hourly space velocity of 60,000 h−1, and the final products were COx, Br2, and HBr, without the formation of other Br-containing organic byproducts. This high catalytic activity was attributed to its high specific area, high surface acidity, and strong redox property. Furthermore, the synergetic effect of Co, Mn, and Ti made it superior for CH2Br2 oxidation. A plausible reaction mechanism for CH2Br2 oxidation over Co–Mn–Ti catalysts was proposed based on the analysis of the products and in situ diffuse-reflectance infrared Fourier transform spectroscopy results.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
