More and more biomolecules are being produced by the biotechnology industry for applications ranging from medicine and food to engineering materials. Liquid chromatography plays a center-stage role in a typical downst...More and more biomolecules are being produced by the biotechnology industry for applications ranging from medicine and food to engineering materials. Liquid chromatography plays a center-stage role in a typical downstream process producing biomolecules such as recombinant proteins. Rigid gigaporous media are porous particles possessing large transecting through-pores with a pore-to-particle diameter ratio of dpore/dparticle〉 0.01. They allow convective flow in the large through-pores, while the smaller diffusion-pores （typically several hundred angstroms in size） supply the needed surface areas. Because of the transecting gigapores, a portion of the mobile phase flows through the pores in addition to fluid flow in the interstitial spaces between the particles in a packed-bed column. This considerably lowers the operating column pressure drop. This lower pressure drop makes axial-direction scale-up of chromatographic columns possible to avoid pancake columns that invariably degrade separation resolution. The large gigapores also make the binding sites on the diffusion pore surfaces more accessible, thus increasing the loading capacity of large protein molecules that can be hindered sterically if only diffusion pores are present. This work discusses the development of rigid gigaporous media and their potential impact on the design of multi-stage downstream process from the angle of multi-scale analysis.展开更多
On the basis of analysis the governing process of downstream water level gates AVIO and AVIS, a mathematical model for simulation of dynamic operation process of hydraulically automated irrigation canals instalIed wit...On the basis of analysis the governing process of downstream water level gates AVIO and AVIS, a mathematical model for simulation of dynamic operation process of hydraulically automated irrigation canals instalIed with AVIO and AVIS gates is presented, the main point of this rnathematical model is firstly applying a set of unsteady flow equations （St. Venant equations here） and treating the condition of gate movement as its dynamic boundary, and then deeoupling this interaction of gate movement with the change of canal flow. In this process, it is necessary to give the gateg open-loop transfer function whose input is water level deviation and output is gate discharge. The result of this simulation for a practical reach has shown it has satisfactory accuracy.展开更多
Bromelain is the denomination given to the group of endoproteases obtained from members of Bromeliacea family. These enzymes have a wide range of proven applications and have been an object of study for worldwide rese...Bromelain is the denomination given to the group of endoproteases obtained from members of Bromeliacea family. These enzymes have a wide range of proven applications and have been an object of study for worldwide researchers for decades. Over the years, several different downstream processes were studied in order to determine which technique would be worthwhile to be implemented in Brazil and provide the national market with such product. The objective of the present study is to relate the main studies in Brazil that has proven that bromelain purification can be cost-effective, in addition to the well-known benefits owned by such enzymes, and highlight the applications that create their market potential in the Brazilian market.展开更多
This study of renaturation by dilution and size exclusion chromatogra phy (SEC) addition of urea to improve yield as well as the initial and final pro tein concentrations showed that although urea decreased the rate o...This study of renaturation by dilution and size exclusion chromatogra phy (SEC) addition of urea to improve yield as well as the initial and final pro tein concentrations showed that although urea decreased the rate of lysozyme ref o lding, it could suppress protein aggregation to sustain the pathway of correct r efolding at high protein concentration; and that there existed an optimum urea c oncentration in renaturation buffer. Under the above conditions, lysozyme was su ccessfully refolded from initial concentration of up to 40 mg/mL by dilution and 100 mg/mL by SEC, with the yield of the former being more than 40% and that of the latter being 34.8%. Especially, under the condition of 30 min interval time, i.e. τ>2(t_R2 -t_R1 ), the efficiency was increased by 25% and the renaturation buffe r could be recycled for SEC refolding in continuous operation of downstream proc ess.展开更多
文摘More and more biomolecules are being produced by the biotechnology industry for applications ranging from medicine and food to engineering materials. Liquid chromatography plays a center-stage role in a typical downstream process producing biomolecules such as recombinant proteins. Rigid gigaporous media are porous particles possessing large transecting through-pores with a pore-to-particle diameter ratio of dpore/dparticle〉 0.01. They allow convective flow in the large through-pores, while the smaller diffusion-pores （typically several hundred angstroms in size） supply the needed surface areas. Because of the transecting gigapores, a portion of the mobile phase flows through the pores in addition to fluid flow in the interstitial spaces between the particles in a packed-bed column. This considerably lowers the operating column pressure drop. This lower pressure drop makes axial-direction scale-up of chromatographic columns possible to avoid pancake columns that invariably degrade separation resolution. The large gigapores also make the binding sites on the diffusion pore surfaces more accessible, thus increasing the loading capacity of large protein molecules that can be hindered sterically if only diffusion pores are present. This work discusses the development of rigid gigaporous media and their potential impact on the design of multi-stage downstream process from the angle of multi-scale analysis.
基金Supported by the 863 Programof China (2001AA242111)
文摘On the basis of analysis the governing process of downstream water level gates AVIO and AVIS, a mathematical model for simulation of dynamic operation process of hydraulically automated irrigation canals instalIed with AVIO and AVIS gates is presented, the main point of this rnathematical model is firstly applying a set of unsteady flow equations （St. Venant equations here） and treating the condition of gate movement as its dynamic boundary, and then deeoupling this interaction of gate movement with the change of canal flow. In this process, it is necessary to give the gateg open-loop transfer function whose input is water level deviation and output is gate discharge. The result of this simulation for a practical reach has shown it has satisfactory accuracy.
文摘Bromelain is the denomination given to the group of endoproteases obtained from members of Bromeliacea family. These enzymes have a wide range of proven applications and have been an object of study for worldwide researchers for decades. Over the years, several different downstream processes were studied in order to determine which technique would be worthwhile to be implemented in Brazil and provide the national market with such product. The objective of the present study is to relate the main studies in Brazil that has proven that bromelain purification can be cost-effective, in addition to the well-known benefits owned by such enzymes, and highlight the applications that create their market potential in the Brazilian market.
文摘This study of renaturation by dilution and size exclusion chromatogra phy (SEC) addition of urea to improve yield as well as the initial and final pro tein concentrations showed that although urea decreased the rate of lysozyme ref o lding, it could suppress protein aggregation to sustain the pathway of correct r efolding at high protein concentration; and that there existed an optimum urea c oncentration in renaturation buffer. Under the above conditions, lysozyme was su ccessfully refolded from initial concentration of up to 40 mg/mL by dilution and 100 mg/mL by SEC, with the yield of the former being more than 40% and that of the latter being 34.8%. Especially, under the condition of 30 min interval time, i.e. τ>2(t_R2 -t_R1 ), the efficiency was increased by 25% and the renaturation buffe r could be recycled for SEC refolding in continuous operation of downstream proc ess.
