Improved elution of isoamylase adsorbed on raw starch and the preservation of purified enzyme

The isoamylase from Pseudomonas amyloderamosa can be recovered by adsorption—elution on raw starch. In this process, the elution of adsorbed isoamylase was significantly affected by elution design. When the raw starch-enzyme suspension was packed into a funnel-type glass filter instead of being stirred in a flask to elute the adsorbed isoamylase, the recovery was increased from 53.6% to about 81% and the concentration of isoamylase was also increased 42-fold in the eluted solution. The addition of 1% potassium sorbate into the eluted enzyme solution gave a retention of more than 80% of the recovered isoamylase activity in a 5-month storage at 4°C.