Qingdao Lan - Academia.edu (original) (raw)

Papers by Qingdao Lan

Research paper thumbnail of Review for "Which model? Comparing fermentation kinetic expressions for cream cheese production

Research paper thumbnail of Nickel nanoparticles synthesized by a modified polyol method for the purification of histidine-tagged single-domain antibody ToxA5.1

Journal of Materials Research, 2012

Nickel nanoparticles (NNPs) synthesized by a modified polyol method using ethylene glycol as a re... more Nickel nanoparticles (NNPs) synthesized by a modified polyol method using ethylene glycol as a reducing agent, palladium chloride as a nucleating agent, and polyvinylpyrrolidone (PVP) as a protective agent were investigated as a potential magnetic adsorbent for the purification of hexahistidine-tagged (His6-tagged) recombinant proteins. The synthesis resulted in nanoparticles having an average diameter of 68 6 28 nm. The x-ray diffraction pattern confirmed the presence of nickel metal, as well as the presence of unreacted nickel (II) hydroxide Ni(OH) 2. Magnetic characterization showed that a magnetization saturation of 39.3 electromagnetic unit (emu)/g at 20,000 Oersted (Oe) was reached rapidly and that the material exhibited ferromagnetic behavior. Protein purification results showed that the synthesized NNPs were highly selective for binding to a His6-tagged recombinant protein single-domain antibody ToxA5.1. In addition, NNPs were used for four adsorption cycles without significant binding capacity losses. These particles have shown great potential such as being easily synthesized, cost-effective, and highly selective magnetic adsorbents for the purification of His6-tagged recombinant proteins.

Research paper thumbnail of A modified Langmuir model for the prediction of the effects of ionic strength on the equilibrium characteristics of protein adsorption onto ion exchange/affinity adsorbents

Chemical Engineering Journal, 2001

An empirical model modified from the Langmuir isotherm model to account for the effects of ionic ... more An empirical model modified from the Langmuir isotherm model to account for the effects of ionic strength on the equilibrium characteristics of protein adsorption onto ion exchange/affinity adsorbents has been proposed and tested against experimental and literature data. The equilibrium isotherms for BSA adsorption onto a polystyrenic anion exchanger, Diaion HPA25, were established for five different NaCl concentrations at 25 • C, pH 7.0. The apparent Langmuir parameters in the new model (q m and K d), which replace the Langmuir parameters (q m and K d) in the original Langmuir model, were determined by non-linear curve fitting. The proposed model has been shown to be applicable to various protein/adsorbent systems.

Research paper thumbnail of Continuous protein recovery using a liquid-solid circulating fluidized bed ion exchange system: Modelling and experimental studies

The Canadian Journal of Chemical Engineering, 2000

I on exchange has long been established as a useful method for protein separation. It is an essen... more I on exchange has long been established as a useful method for protein separation. It is an essential component in many protein purification processes. In the fields of pharmaceutical and food industries, many valuable proteins are produced in large-scale with low initial protein ...

Research paper thumbnail of A new kinetic model of protein adsorption on suspended anion-exchange resin particles

Biotechnology and Bioengineering, 1999

The kinetics of adsorption of bovine serum albumin on an anion-exchange resin were measured in a ... more The kinetics of adsorption of bovine serum albumin on an anion-exchange resin were measured in a batch system using a flow cell and ultraviolet absorbance, as a function of initial liquid-phase protein concentration and solid-to-liquid phase ratio. A new mathematical model for adsorption kinetics is presented that fits the experimental data to give a highly linear relationship with time, following a short transient period. Numerical integration of the differential form of the new composite nonlinear (CNL) kinetic model, containing three independent parameters, is shown to describe the dynamics of batch adsorption much better than alternative lumped parameter models. Although the new model is phenomenological rather than mechanistic, its principal parameter is shown to be a direct linear function of a physically measurable quantity. This study demonstrates that the model can accurately simulate protein concentration-time profiles using parameter estimates derived from correlations over a wide range of initial protein concentrations and phase ratios. The new CNL model is shown to be considerably superior to the Langmuir and solid-film linear kinetic models in this regard, having the additional advantage that an equilibrium isotherm for the system is not required.

Research paper thumbnail of Continuous protein recovery with a liquid–solid circulating fluidized-bed ion exchanger

AIChE Journal, 2002

... Qingdao Lan, Amarjeet S. Bassi, Jing-Xu Jesse Zhu, and Argyrios Margaritis Dept. ... Continuo... more ... Qingdao Lan, Amarjeet S. Bassi, Jing-Xu Jesse Zhu, and Argyrios Margaritis Dept. ... Continuous ion exchange using different fluidized-bed Ž systems has been extensively investigated Turner and Church, 1963; Higgins, 1969; Slater and Prud'homme, 1972; Porter, 1975; Himsley ...

Research paper thumbnail of Continuous protein recovery from whey using liquid-solid circulating fluidized bed ion-exchange extraction

Biotechnology and Bioengineering, 2002

A liquid-solid circulating fluidized bed (LSCFB) continuous ion-exchange extraction system has be... more A liquid-solid circulating fluidized bed (LSCFB) continuous ion-exchange extraction system has been investigated for total protein recovery from whey solutions under various operating conditions. The effectiveness of a dynamic seal was evaluated between the riser and the downcomer, and the best conditions for the establishment of this seal were established. Start-up studies indicated that the system is robust and stable. Under optimal conditions, a productivity of 8.2 g of total protein removed per hour per kilogram of resin was achieved with a protein removal efficiency of 78.4%. However, higher overall protein recovery of up to 90% was also achieved under other conditions, with lower protein concentration in the effluent and a lower overall productivity.

Research paper thumbnail of Review for "Which model? Comparing fermentation kinetic expressions for cream cheese production

Research paper thumbnail of Nickel nanoparticles synthesized by a modified polyol method for the purification of histidine-tagged single-domain antibody ToxA5.1

Journal of Materials Research, 2012

Nickel nanoparticles (NNPs) synthesized by a modified polyol method using ethylene glycol as a re... more Nickel nanoparticles (NNPs) synthesized by a modified polyol method using ethylene glycol as a reducing agent, palladium chloride as a nucleating agent, and polyvinylpyrrolidone (PVP) as a protective agent were investigated as a potential magnetic adsorbent for the purification of hexahistidine-tagged (His6-tagged) recombinant proteins. The synthesis resulted in nanoparticles having an average diameter of 68 6 28 nm. The x-ray diffraction pattern confirmed the presence of nickel metal, as well as the presence of unreacted nickel (II) hydroxide Ni(OH) 2. Magnetic characterization showed that a magnetization saturation of 39.3 electromagnetic unit (emu)/g at 20,000 Oersted (Oe) was reached rapidly and that the material exhibited ferromagnetic behavior. Protein purification results showed that the synthesized NNPs were highly selective for binding to a His6-tagged recombinant protein single-domain antibody ToxA5.1. In addition, NNPs were used for four adsorption cycles without significant binding capacity losses. These particles have shown great potential such as being easily synthesized, cost-effective, and highly selective magnetic adsorbents for the purification of His6-tagged recombinant proteins.

Research paper thumbnail of A modified Langmuir model for the prediction of the effects of ionic strength on the equilibrium characteristics of protein adsorption onto ion exchange/affinity adsorbents

Chemical Engineering Journal, 2001

An empirical model modified from the Langmuir isotherm model to account for the effects of ionic ... more An empirical model modified from the Langmuir isotherm model to account for the effects of ionic strength on the equilibrium characteristics of protein adsorption onto ion exchange/affinity adsorbents has been proposed and tested against experimental and literature data. The equilibrium isotherms for BSA adsorption onto a polystyrenic anion exchanger, Diaion HPA25, were established for five different NaCl concentrations at 25 • C, pH 7.0. The apparent Langmuir parameters in the new model (q m and K d), which replace the Langmuir parameters (q m and K d) in the original Langmuir model, were determined by non-linear curve fitting. The proposed model has been shown to be applicable to various protein/adsorbent systems.

Research paper thumbnail of Continuous protein recovery using a liquid-solid circulating fluidized bed ion exchange system: Modelling and experimental studies

The Canadian Journal of Chemical Engineering, 2000

I on exchange has long been established as a useful method for protein separation. It is an essen... more I on exchange has long been established as a useful method for protein separation. It is an essential component in many protein purification processes. In the fields of pharmaceutical and food industries, many valuable proteins are produced in large-scale with low initial protein ...

Research paper thumbnail of A new kinetic model of protein adsorption on suspended anion-exchange resin particles

Biotechnology and Bioengineering, 1999

The kinetics of adsorption of bovine serum albumin on an anion-exchange resin were measured in a ... more The kinetics of adsorption of bovine serum albumin on an anion-exchange resin were measured in a batch system using a flow cell and ultraviolet absorbance, as a function of initial liquid-phase protein concentration and solid-to-liquid phase ratio. A new mathematical model for adsorption kinetics is presented that fits the experimental data to give a highly linear relationship with time, following a short transient period. Numerical integration of the differential form of the new composite nonlinear (CNL) kinetic model, containing three independent parameters, is shown to describe the dynamics of batch adsorption much better than alternative lumped parameter models. Although the new model is phenomenological rather than mechanistic, its principal parameter is shown to be a direct linear function of a physically measurable quantity. This study demonstrates that the model can accurately simulate protein concentration-time profiles using parameter estimates derived from correlations over a wide range of initial protein concentrations and phase ratios. The new CNL model is shown to be considerably superior to the Langmuir and solid-film linear kinetic models in this regard, having the additional advantage that an equilibrium isotherm for the system is not required.

Research paper thumbnail of Continuous protein recovery with a liquid–solid circulating fluidized-bed ion exchanger

AIChE Journal, 2002

... Qingdao Lan, Amarjeet S. Bassi, Jing-Xu Jesse Zhu, and Argyrios Margaritis Dept. ... Continuo... more ... Qingdao Lan, Amarjeet S. Bassi, Jing-Xu Jesse Zhu, and Argyrios Margaritis Dept. ... Continuous ion exchange using different fluidized-bed Ž systems has been extensively investigated Turner and Church, 1963; Higgins, 1969; Slater and Prud'homme, 1972; Porter, 1975; Himsley ...

Research paper thumbnail of Continuous protein recovery from whey using liquid-solid circulating fluidized bed ion-exchange extraction

Biotechnology and Bioengineering, 2002

A liquid-solid circulating fluidized bed (LSCFB) continuous ion-exchange extraction system has be... more A liquid-solid circulating fluidized bed (LSCFB) continuous ion-exchange extraction system has been investigated for total protein recovery from whey solutions under various operating conditions. The effectiveness of a dynamic seal was evaluated between the riser and the downcomer, and the best conditions for the establishment of this seal were established. Start-up studies indicated that the system is robust and stable. Under optimal conditions, a productivity of 8.2 g of total protein removed per hour per kilogram of resin was achieved with a protein removal efficiency of 78.4%. However, higher overall protein recovery of up to 90% was also achieved under other conditions, with lower protein concentration in the effluent and a lower overall productivity.