摘要
To improve protein separation and purification directly from a fermentation broth, a novel membrane filtration-cum-chromatography device configuration having a relatively impermeable coated zone near the hollow fiber module outlet has been developed. The integrated membrane filtration-cum-chromatography unit packed with chromatographic beads on the shell side of the hollow fiber unit enjoys the advantages of both membrane filtration and chromatography; it allows one to load the chromatographic media directly from the fermentation broth or lysate and separate the adsorbed proteins through the subsequent elution step in a cyclic process. Interfacial polymerization was carried out to coat the bottom section of the hollow fiber membrane while leaving the rest of the hollow fiber membrane unaffected. Myoglobin (Mb), bovine serum albumin (BSA) and α-lactalbumin (α-LA) were used as model proteins in binary mixtures. Separation behaviors of binary protein mixtures were studied in devices using either an ultrafiltration (UF) membrane or a microfiltration (MF) membrane. Experimental results show that the breakthrough time and the protein loading capacities were dramatically improved after coating in both UF and MF modules. For a synthetic yeast fermentation broth feed, the Mb and α-LA elution profiles for the four consecutive cyclic runs were almost superimposable. Due to the lower transmembrane flux in this device plus the periodical washing-elution during the chromatographic separation, fouling was not a problem as it is in conventional microfiltration. A mathematical model describing the hydrodynamic and protein loading behaviors of the integrated device using UF membrane with a coated zone was developed. The simulation results for the breakthrough agree well with the experimental breakthrough curves. The optimal length of the coated zone was obtained from the simulation. A theoretical analysis of the protein mass transfer was performed using a diffusion-convection model considering the feed-side concentration polarization and the permeate-side concentration gradient formed by the adsorption. The permeate-side adsorption can enhance the observed protein transmission through the membrane considerably at low permeate flux. But the enhancement effect can be neglected at higher permeate flux when convection dominates the total mass transfer process or the proteins are very highly rejected by the membrane.
摘要译文
为了改进从发酵液蛋白的分离和纯化，直接，已经开发了具有邻近中空纤维组件出口的相对不透水涂覆区的新的膜过滤暨色谱设备配置。填充在中空纤维单元的壳侧色谱珠的集成膜过滤暨色谱单元都享有膜过滤和层析的优点;它允许一个直接从发酵液或裂解物装载的色谱介质，并通过在一个循环过程的后续洗脱步骤中分离的被吸附的蛋白质。界面聚合进行涂覆的中空纤维膜的底部，同时使中空纤维膜未受影响的其余部分。肌红蛋白（MB），牛血清白蛋白（BSA），α乳白蛋白（α-LA）用作在二元混合物模型的蛋白质。二元蛋白混合物的分离行为进行了研究，使用任一个超滤（UF）膜或微滤（MF）膜的设备。实验结果表明，穿透时间和蛋白装载能力都超滤和MF模块涂布后显着改善。对于人工合成酵母发酵液的饲料，为连续四个循环运行的MB和α-LA洗脱曲线几乎重叠。由于在该装置中加上在色谱分离过程中的周期性清洗，洗脱下跨膜通量，结垢不是问题，因为它是在常规微滤。开发利用描述UF膜涂层区域集成器件的流体动力学和蛋白质装载行为的数学模型。仿真结果为突破同意与实验突破曲线。从模拟中获得的涂层区的最佳长度。使用的扩散对流模型考虑进料侧的浓度极化和通过吸附形成的渗透侧的浓度梯度进行了蛋白质质量转移的理论分析。渗透物侧的吸附可通过该膜在低渗透通量提高观察蛋白质传输相当。但增强效果可以在更高的渗透通量可以忽略时对流占主导地位的总传质过程或蛋白通过该膜非常高度拒绝。
Xu, Yanke. Studies on improved integrated membrane-based chromatographic process for bioseparation[D]. US: New Jersey Institute of Technology, 2004