Fundamental Bioengineering

13Purification of Bio-Products

Sunil Nath

Summary

The objective of all recovery processes (described in Chapter 12) is to obtain the desired purity and yield for a product, and techniques for purification are aimed to remove impurities closely related to the properties of the product. Column chromatography processes constitute the workhorse for purification of biochemical products at an analytical and even a preparative scale. The name originates from the first applications of the technique a century ago when solutions of dyes or vegetable pigments were resolved into bands of various colors by passing them through a column of fine particles (the solid or stationary phase). Molecular sieves, gels, or nonionic resins may be readily used as the stationary phase in column chromatographic processes. The column is packed with beads of solids and a feed solution (the mobile phase) is made to flow through the column and eluted with a suitable solvent, typically water for fermentation products. The separation media selectively slows certain solute components in the feed solution, while other components rapidly move down the column. This leads to a separation as the solutes are transported through the column, and the purity of the respective solutes gets enhanced. Ultimately, the feed components appear (“elute”) at different times at the outlet of the chromatography column and can be collected separately. This chapter attempts to summarize aspects of the application of chromatographic ...