Shukla R, Balakrishnan M, Agarwal G P
Agricultural Bioprocess Laboratory, University of Illinois at Urbana-Champaign 61801, USA.
Bioseparation. 2000;9(1):7-19. doi: 10.1023/a:1008194300403.
This work investigates the fractionation of similar molecular weight proteins bovine serum albumin (69 kD) and bovine hemoglobin (67 kD) by ultrafiltration. Three different membranes, viz. regenerated cellulose, poly(sulfone) and surface modified poly(acrylonitrile), each with a nominal molecular cutoff rating of 100 kD, were examined. The experiments were conducted in dead end, crossflow and vortex flow filtration modes and the separation was studied as a function of feed pH and ionic strength. Under similar system hydrodynamics, the surface modified poly(acrylonitrile) membrane displayed the highest resolution with minimum membrane fouling. The separation could be improved further by operating at low applied pressure (40 kPa) and high mass transfer (> 20 x 10(-6) m/s) in a vortex flow module. Under these conditions, the highest separation factor of 40 was obtained at the pI of hemoglobin.
本研究通过超滤对分子量相近的蛋白质——牛血清白蛋白（69 kD）和牛血红蛋白（67 kD）进行分级分离。考察了三种不同的膜，即再生纤维素膜、聚砜膜和表面改性聚丙烯腈膜，其截留分子量均标称100 kD。实验在死端过滤、错流过滤和旋流过滤模式下进行，并研究了分离效果随进料pH值和离子强度的变化。在相似的系统流体力学条件下，表面改性聚丙烯腈膜表现出最高的分辨率，且膜污染最小。在旋流过滤模块中，通过在低施加压力（40 kPa）和高传质速率（> 20×10⁻⁶ m/s）下操作，分离效果可进一步提高。在此条件下，在血红蛋白的等电点处获得了最高40的分离因子。
