Breakage of unstable protein crystals in mechanical solid-liquid separation processes

机械固液分离过程中不稳定蛋白质晶体的破碎

• 批准号: 315011332
• 负责人: Professor Dr.-Ing. Hermann Nirschl
• 金额: --
• 依托单位: Arbeitsgruppe Verfahrenstechnische Maschinen (VM)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/315011332?language=en
• 关键词: Breakage; unstable; protein; crystals; mechanical

As part of the DFG priority program “Disperse, structural and phase changes of proteins and biological agglomerates in biotechnological processes (DiSP Biotech)”, the applicant is investigating the filtration and fracture behavior of mechanically labile protein crystals. The comprehensive analysis of biotechnological processes from cultivation to formulation on the micro to macro scale aims to better understand and optimize the entire process chain. Cornehl et al. showed that crystal size, shape and breakage have a strong influence on the filtration performance of lysozyme crystals. Both, protein expression and crystallization, affect crystal morphology and breakage behavior. Modifications and optimizations of the proteins or crystals have an effect on the subsequent process steps. Ultimately, it must be ensured that the target product passes the complete process chain successfully.The process functions (flux density function and compressive yield stress), which were determined by centrifugal filtration on a small scale in the first project phase, do not take any inhomogeneity of the filter cake into account. In the case of centrifugal filtration the maximum pressure is applied to the bottom of the filter cake, which leads to an inhomogeneous breakage behavior. Pressure stressed filter cakes show a shift in crystal size distribution towards smaller crystals. In addition to the compressive stress, shear stress also occurs in technical filtration processes, which results in crystal breakage and reduces the crystal size. The influence of shear stress on the cake structure and the process functions for protein crystals has to be clarified within the scope of this research project.The μCT analysis allows to investigate structural differences in the filter cake and to determine the crystal size distribution. Models for correcting and transferring process functions from a small-scale to larger filtration units do not exist for mechanically labile protein crystals. However, this is a prerequisite for the application of the process functions to calculate the filtration behavior on larger separation apparatuses. Hence, such a model has to be developed in this project. Supported by CFD simulations, the optimization of separation apparatuses under consideration of breakage mechanisms will be carried out. With 3D printing and rapid prototyping constructive improvements of the filtration apparatus can be realized and compared with regard to the filtration behavior and crystal breakage.

作为DFG优先项目“生物技术过程中蛋白质和生物聚集体的分散、结构和相变"的一部分，申请人正在研究机械不稳定蛋白质晶体的过滤和断裂行为。从微观到宏观的生物技术过程的全面分析旨在更好地了解和优化整个过程链。Cornehl等人表明，晶体大小、形状和破碎对溶菌酶晶体的过滤性能有很大影响。蛋白质表达和结晶都影响晶体形态和断裂行为。蛋白质或晶体的修饰和优化对后续工艺步骤有影响。最终，必须确保目标产品成功通过整个工艺链。在第一个项目阶段通过小规模离心过滤确定的工艺功能（通量密度功能和压缩屈服应力）没有考虑滤饼的任何不均匀性。在离心过滤的情况下，最大压力施加到滤饼的底部，这导致不均匀的破碎行为。压力应力滤饼显示出晶体尺寸分布向更小晶体的转变。除了压缩应力之外，剪切应力也发生在技术过滤过程中，这导致晶体破碎并减小晶体尺寸。在本研究项目的范围内，必须明确剪切应力对滤饼结构和蛋白质晶体工艺功能的影响。μCT分析可以研究滤饼的结构差异，并确定晶体粒度分布。对于机械不稳定的蛋白质晶体，不存在用于将过程功能从小规模过滤单元校正和转移到较大过滤单元的模型。然而，这是应用过程函数计算较大分离设备上过滤行为的先决条件。因此，在这个项目中必须开发这样一个模型。在CFD模拟的支持下，将进行考虑破碎机理的分离装置的优化。通过3D打印和快速成型，可以实现过滤装置的结构性改进，并在过滤行为和晶体破碎方面进行比较。