Mathematical modeling of salt-gradient ion-exchange simulated moving bed chromatography for protein separations

The salt-gradient operation mode used in ion-exchange simulated moving bed chromatography (SMBC) can improve the efficiency of protein separations. A detailed model that takes into account any kind of adsorption/ion-exchange equilibrium, salt gradient, size exclusion, mass transfer resistance, and port periodic switching mechanism, was developed to simulate the complex dynamics. The model predictions were verified by the experimental data on upward and downward gradients for protein separations reported in the literature. All design and operating parameters (number, configuration, length and diameter of columns, particle size, switching period, flow rates of feed, raffinate, desorbent and extract, protein concentrations in feed, different salt concentrations in desorbent and feed) can be chosen correctly by numerical simulation. This model can facilitate the design, operation, optimization, control and scale-up of salt-gradient ion-exchange SMBC for protein separations.

坛紫菜藻红蛋白的规模化制备

为了优化坛紫菜粗提工艺以减轻纯化的压力,研究了我国主要经济红藻之一坛紫菜藻红蛋白大规模制备方法。实验采用"溶胀+组织捣碎"法破碎坛紫菜叶状体细胞,对比了多次硫酸铵梯度盐析对破碎液中藻红蛋白的影响,并进一步用羟基磷灰石层析制备藻红蛋白,最后对所得蛋白做了光谱和电泳鉴定。结果表明,经过4次盐析,藻红蛋白吸收光谱纯度达到0.9(A564/A280),每次的最佳盐析浓度分别为15%、50%、10%和40%;7 kg阴干紫菜经过4次盐析和1次羟基磷灰石层析后可获得507.82 mg藻红蛋白(A564/A280>3.2),为进一步研究规模高效分离纯化藻红蛋白提供了参考。

竹叶天然抗菌肽的分离纯化与抗菌活性研究

利用PBS浸提、硫酸铵梯度盐析、弱阴离子交换色谱DEAE-A50,从竹叶中分离纯化出一种新的抗菌肽。该活性多肽经纯化后在SDS-PAGE上显示为两条带,分子量分别为49 888 Da和45 604 Da。此竹叶多肽对大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)以及枯草芽孢杆菌(Bacillus subtilis)表现出良好的抑菌活性。