The foam fractionation of nisin from its fermentation broth was studied.Two types of devices consisting of a rubber piston and a foam riser were developed to enhance foam drainage.The separation performance of these t...The foam fractionation of nisin from its fermentation broth was studied.Two types of devices consisting of a rubber piston and a foam riser were developed to enhance foam drainage.The separation performance of these two devices was investigated.Experimental results indicated that the second device could significantly reduce the liquid fraction of the foam leaving the column,εout,leading to a higher enrichment of the out-flow stream.As its mounting height increased from 0 to 15 cm,εout declined from 7.07‰ to 6.13 ‰ and the maximum nisin activity in the foamate could reach 39.6 IU/μL.The slight increase in nisin inactivation rate indicated the applicability of this method in the recovery and concentration of proteins.Finally,the mechanism of the process was primarily explained by invoking recent work on pneumatic foams.This research provides a basis for the design of multistage draining foam fractionator which could potentially be an effective separation equipment.展开更多
A thorough understanding of how proteins induce nanoparticle （NP） aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developi...A thorough understanding of how proteins induce nanoparticle （NP） aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developing nano-applications and formulation for drug delivery systems. In this study, we found that extraction of immunoglobulin G （IgG） from cow serum results in lower polystyrene NPs aggregation. Moreover, addition of isolated IgG or fibrinogen to fetal cow serum enhanced this aggregation, thus demonstrating that these factors are major drivers of NP aggregation in serum. Counter-intuitively, NP aggregation was inversely dependent on protein concentration; i.e., low protein concentrations induced large aggregates, whereas high protein concentrations induced small aggregates. Protein-induced NP aggregation and aggregate size were monitored by absorbance at 400 nm and dynamic light scattering, respectively. Here, we propose a mechanism behind the protein concentration dependent aggregation; this mechanism involves the effects of multiple protein interactions on the NP surface, surface area limitations, aggregation kinetics, and the influence of other serum proteins.展开更多
基金supported by Natural Science Foundation of Tianjin (Grant No. 08JCZDJC25200)Natural Science Research Program of Hebei Province (Grant No. Z2008310)
文摘The foam fractionation of nisin from its fermentation broth was studied.Two types of devices consisting of a rubber piston and a foam riser were developed to enhance foam drainage.The separation performance of these two devices was investigated.Experimental results indicated that the second device could significantly reduce the liquid fraction of the foam leaving the column,εout,leading to a higher enrichment of the out-flow stream.As its mounting height increased from 0 to 15 cm,εout declined from 7.07‰ to 6.13 ‰ and the maximum nisin activity in the foamate could reach 39.6 IU/μL.The slight increase in nisin inactivation rate indicated the applicability of this method in the recovery and concentration of proteins.Finally,the mechanism of the process was primarily explained by invoking recent work on pneumatic foams.This research provides a basis for the design of multistage draining foam fractionator which could potentially be an effective separation equipment.
文摘A thorough understanding of how proteins induce nanoparticle （NP） aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developing nano-applications and formulation for drug delivery systems. In this study, we found that extraction of immunoglobulin G （IgG） from cow serum results in lower polystyrene NPs aggregation. Moreover, addition of isolated IgG or fibrinogen to fetal cow serum enhanced this aggregation, thus demonstrating that these factors are major drivers of NP aggregation in serum. Counter-intuitively, NP aggregation was inversely dependent on protein concentration; i.e., low protein concentrations induced large aggregates, whereas high protein concentrations induced small aggregates. Protein-induced NP aggregation and aggregate size were monitored by absorbance at 400 nm and dynamic light scattering, respectively. Here, we propose a mechanism behind the protein concentration dependent aggregation; this mechanism involves the effects of multiple protein interactions on the NP surface, surface area limitations, aggregation kinetics, and the influence of other serum proteins.
