Reaction-integrated separation of isomaltose by ad- and desorption on zeolite

• Published in: Chemical engineering and processing Vol. 48; no. 4; pp. 852 - 858
• Main Authors: Holtkamp, M., Erhardt, F.A., Jördening, H.-J., Scholl, S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2009; Elsevier
• Subjects: Adsorption; Applied sciences; Chemical engineering; Exact sciences and technology; Isomaltose; Process intensification; Reaction-integrated adsorption; Temperature swing desorption; Zeolite; Process intensification; Reaction-integrated adsorption; Zeolite; Temperature swing desorption; Isomaltose; Packed bed; Adsorption capacity; Desorption; Countercurrent flow; Design; Continuous process; Adsorption; Batchwise
• ISSN: 0255-2701; 1873-3204
• DOI: 10.1016/j.cep.2008.11.001

This paper describes studies carried out into downstream processing for an enzymatic system producing isomaltose by glucosyltransfer, in which the isomaltose appears as an intermediate in a consecutive reaction chain. To avoid these consecutive reactions, reaction-integrated separation by adsorption was established. A specific β-zeolite was investigated as a selective adsorbent for the product isomaltose, and the influence of eluent and temperature on the desorption process was researched. As eluent, 50% (v/v) ethanol and pure water were compared. Using 50% ethanol the amount of desorbed isomaltose is about 23% higher than in pure water. In both cases desorption takes place over a period of more than 50 h and at a temperature of 70 °C. Residual moisture on zeolite significantly decreases adsorption capacity. In batch experiments, the half-life of zeolite stored in water is about 50 h, but for a continuous flow in a packed bed column, the half-life decreases to 7 h. Based on these findings, a design for downstream processing is proposed using a counter-current flow temperature swing displacement desorption sequence. Here, product concentration can be increased by multiple usage of the desorption liquid.