Jump to ContentJump to Main Navigation
Bioseparations Science and Engineering$
Users without a subscription are not able to see the full content.

Roger G. Harrison, Paul W. Todd, Scott R. Rudge, and Demetri P. Petrides

Print publication date: 2015

Print ISBN-13: 9780195391817

Published to Oxford Scholarship Online: November 2020

DOI: 10.1093/oso/9780195391817.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (oxford.universitypressscholarship.com). (c) Copyright Oxford University Press, 2021. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 24 October 2021



(p.362) 9 Crystallization
Bioseparations Science and Engineering

Roger G. Harrison

Paul W. Todd

Scott R. Rudge

Demetri P. Petrides

Oxford University Press

Crystallization is the process of producing crystals from a homogeneous phase. For biochemicals, the homogeneous phase from which crystals are obtained is always a solution. Crystallization is similar to precipitation in that solid particles are obtained from a solution. However, precipitates have poorly defined morphology, while in crystals the constituent molecules are arranged in three-dimensional arrays called space lattices. In comparison to crystallization, precipitation occurs at much higher levels of supersaturation and rates of nucleation but lower solubilities. These and other differences between crystallization and precipitation are highlighted in Table 9.1. Because of these differences and because the theory of crystallization that has been developed is different from that for precipitation, crystallization is considered separately from precipitation. Crystallization is capable of producing bioproducts at very high purity (say, 99.9%) and is considered to be both a polishing step and a purification step. Polishing refers to a process needed to put the bioproduct in its final form for use. For some bioproducts, such as antibiotics, this final form must be crystalline, and sometimes it is even necessary that a specific crystal form be obtained. In some instances, the purification that can be achieved by crystallization is so significant that other more expensive purification steps such as chromatography can be avoided. There are actually two very different applications of crystallization in biotechnology and bioproduct engineering: crystallization for polishing and purification, and crystallization for crystallography. In the latter case, the goal is a small number of crystals with good size (0.2–0.9 mm) and internal quality. Although it has become common to crystallize proteins for characterization of their three-dimensional structure by x-ray diffraction, this is performed only at small scale in the laboratory, and the knowledge about how to crystallize proteins at large scale in a production process is less developed. However, many antibiotics and other small biomolecules are routinely crystallized in production scale processes. This chapter is oriented toward the use of crystallization in processes that can be scaled up.

Keywords:   Reynolds number, crystallization, mixing, mother liquor, population balances

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .