Sweet potato #beta#-amylase immobilized on chitosan beads and its application in the semi-continuous production of maltose

摘要

The present study is concerned with the immobilization of #beta#-amylase from sweet potato tuberous roots on chitosan beads for the purpose of maltose production. Immobilized sweet potato #beta#-amylase on Chitopearl BCW 3505 beads exhibited an activity of 142 U/g carrier. The optimum temperature of the immobilized #beta#-amylase increased by 20 degC, and thermostability was improved by about 10 degC compared to free #beta#-amylase. The additional effects of two types of the immobilized pullulanases on maltose formation were also investigated. The addition of pullulanase from Bacillus brevis gave a higher yield of maltose compared to that from Klebsiella pneumoniae. A semi-continuous production of maltose from a highly concentrated substrate (Pine-Dex #1, potato starch hydrolyzate) solution (40%, w/v) with the immobilized sweet potato #beta#-amylase and Bacillus brevis pullulanase could be obtained at pH 6.0 and 60 degC for 14 days at a higher yield (70.9%) using a horizontal rotary column reactor.