Ion Exchange frederick j. Dechow 1.0 INTRODUCTION In 1850 Thompson reported the first ion exchange applications which used naturally occurring clays. However, ion exchange resins have only been used in biochemical and fermentation product recovery since the 1930s / In these early studies, biochemicals such as adenosine triphos phate, 4 alcohols, 5I alkaloids, 6) amino acids, 7 growth regulators, 3I hor- mones,penicillin[ol and vitamin B12 i were purified using ion exchange resins Ion exchange applications intensified following the work of Moore and Stein, [2 which showed that very complex mixtures of biochemicals, in this case amino acids and amino acid residues could be isolated from each other using the ion exchange resin as a column chromatographic separator. In biotechnology applications today, ion exchangers are important in preparing water of the necessary quality to enhance the desired microorganism activity during fermentation. Downstream of the fermentation, ion exchange resins may be used to convert, isolate, purify or concentrate the desired product or by-products. This chapter discusses ion exchange resins and their use in commercial fermentation and protein purification operations 382Ion Exchange Frederick J. Dechow 1.0 INTRODUCTION In 1850 Thompson['] reported the first ion exchange applications which used naturally occurring clays. However, ion exchange resins have only been used in biochemical and fermentation product recovery since the 1930'~.[~1[~] In these early studies, biochemicals such as adenosine triphos￾phate,i4] alcohols,[5] alkaloids,[6] amino acids,['] growth regulators,[*] hor￾mone~,[~] penicillin[10] and vitamin B12["1 were purified using ion exchange resins. Ion exchange applications intensified following the work of Moore and Stein,[12] which showed that very complex mixtures of biochemicals, in this case, amino acids and amino acid residues could be isolated from each other using the ion exchange resin as a column chromatographic separator. In biotechnology applications today, ion exchangers are important in preparing water of the necessary quality to enhance the desired microorganism activity during fermentation. Downstream of the fermentation, ion exchange resins may be used to convert, isolate, purify or concentrate the desired product or by-products. This chapter discusses ion exchange resins and their use in commercial fermentation and protein purification operations. 382