Evaluation of gluteraldehyde-modified chitosan as a matrix for hydrophobic interaction chromatography

Gluteraldehyde modified chitosan was investigated as matrix for hydrophobic interaction chromatography, by studying binding of six different enzymes/proteins to the matrix. In all cases, except one, there was a substantial increase in the binding of enzyme activity to chitosan after modification with gluteraldehyde. The binding was mediated by both electrostatic and hydrophobic interactions. Alkaline phosphatase was found to bind in the presence of 2.4 M (NH4)2SO4. It appears that in the presence of such a high salt concentration, binding was mostly due to hydrophobic interactions. 99% of the bound activity could be recovered after elution with 50% ethylene glycol. The eluted enzyme showed a 4.5-fold purification. Thus modified chitosan described here can be used for hydrophobic interaction chromatography as successfully illustrated with alkaline phosphatase.